Water Management and Irrigation Assessment and...
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1 This project is funded by The European Commission A project implemented by HTSPE Limited European Commission Water Management and Irrigation Assessment and Development Final Report Project No. 2013/315545 - Version 1
Transcript of Water Management and Irrigation Assessment and...
1
This project is funded by The European Commission
A project implemented by HTSPE Limited
European Commission
Water Management and Irrigation Assessment and Development
Final Report
Project No. 2013/315545 - Version 1
2
HTSPE Limited
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This publication has been produced with the assistance of the European Union. The contents of this
publication are the sole responsibility of HTSPE Limited and can in no way be taken to reflect the
views of the European Union.
(5013027)
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Trinidad and Tobago European Union
CONSULTANCY SERVICES
FWC BENEFICIARIES 2009 LOT 1: Rural development
Europe Aid/127054/C/SER/multi Contract no. 2013/315545
Final Report
WATER MANAGEMENT AND IRRIGATION ASSESSMENT AND DEVELOPMENT
OF THE FELICITY SITE, CENTRAL TRINIDAD
September 2013
CONTENTS
1. INTRODUCTION ........................................................................................................... 19
2. OBJECTIVES OF THE PROJECT ................................................................................ 21
3. OVERVIEW OF THE NATIONAL SUGAR ADAPTATION STRATEGY (NAS) ............ 22
3.1 The National Sugar Adaptation Strategy (NAS) ..................................................... 22
3.2 Caroni (1975) Limited ............................................................................................. 22
3.3 Assistance from the EU .......................................................................................... 23
4. RELEVANT PROJECTS AND PROGRAMMES ........................................................... 24
4.1 Caparo River Basin Flood Mitigation and Water Supply Project ............................ 24
4.2 Caroni Green Initiative (CGI) .................................................................................. 25
4.3 Agricultural Incentive Programme (AIP) ................................................................. 25
5. STAKEHOLDERS ......................................................................................................... 26
5.1 Introduction ............................................................................................................. 26
5.2 Recipient Stakeholders ........................................................................................... 26
5.3 Supporting Stakeholders ........................................................................................ 26
5.4 Stakeholder Contact ............................................................................................... 27
6. EXISTING SITUATION IN THE FELICITY AGRICULTURAL AREA ........................... 28
6.1 Caroni (1975) Ltd. Lands ........................................................................................ 28
6.2 Land lying fallow .................................................................................................... 28
6.3 Drainage, Flooding and Irrigation ........................................................................... 28
6.4 Transfer to Non Subsidised Agriculture .................................................................. 29
6.5 Needs Assessment ................................................................................................. 29
6.6 Institutional Arrangements for Water Resources Management .............................. 30
7. CONSULTATIONS WITH FAMERS, FARMERS ASSOCIATIONS ............................. 31
7.1 The Felicity Project Area ........................................................................................ 31
7.2 International Experiences with Water User Associations (WUAs) .......................... 32
8. CHARACTERISTICS OF THE FELICITY PROJECT AREA ........................................ 34
8.1 Introduction ............................................................................................................. 34
8.2 Morphology ............................................................................................................. 34
8.3 Geology .................................................................................................................. 34
8.4 Soils ........................................................................................................................ 34
8.5 Socio-Economical Aspects ..................................................................................... 35
9. CLIMATE AND CLIMATE CHANGE ............................................................................ 36
9.1 Climate of Trinidad ................................................................................................. 36
9.1.1 Rainfall ............................................................................................................ 36
9.1.2 Evaporation and evapo-transpiration .............................................................. 37
9.1.3 Wind ................................................................................................................ 38
9.2 Climate Change ...................................................................................................... 39
9.2.1 Change in temperature .................................................................................... 39
9.2.2 Change in precipitation .................................................................................... 40
9.2.3 Sea level rise ................................................................................................... 40
9.2.4 Impacts and mitigation measures .................................................................... 40
10. HYDROGEOLOGY .................................................................................................... 42
10.1 Introduction ............................................................................................................. 42
10.2 Aquifers in Central Trinidad .................................................................................... 42
10.3 Potential of Groundwater in the Project Area ......................................................... 42
11. WATER QUALITY ..................................................................................................... 44
11.1 Ground Water Quality ............................................................................................. 44
11.2 Surface Water Quality and Salt Water Intrusion ..................................................... 45
11.3 Test Results on Water from the Felicity Project Area ............................................. 45
11.3.1 Pesticides ........................................................................................................ 45
11.3.2 General chemical/physical parameters ........................................................... 45
11.3.3 Sodium Adsorption Ratio (SAR) Values ........................................................... 46
11.3.4 Conclusions ..................................................................................................... 47
12. ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES .............................. 49
12.1 Introduction ............................................................................................................. 49
12.2 Positive Impact on the Socio-Economic Situation .................................................. 49
12.3 Strategic Environmental Assessment and Environmental Sustainability Plan ........ 49
12.4 Impacts on Water and from Water .......................................................................... 50
12.5 Impacts on Soil ....................................................................................................... 50
12.6 Impacts on Flora and Fauna (biodiversity) ............................................................. 51
12.7 Impacts on Landscape ........................................................................................... 51
12.8 Impacts on Human health ....................................................................................... 51
12.8.1 Pesticides and fertilisers .................................................................................. 51
12.8.2 Re-use of irrigation water and use of untreated wastewater ........................... 52
12.8.3 Waterborne diseases ...................................................................................... 53
13. IRRIGATION SECTOR STUDY ................................................................................. 54
13.1 Water resources in the former sugar growing areas .............................................. 54
13.2 Current, future and potential agricultural water resource needs ............................. 56
13.2.1 National situation irrigated areas ..................................................................... 56
13.2.2 Former Sugar Growing Areas – potential irrigation demand ........................... 57
13.2.3 Irrigation water requirements – approach ........................................................ 58
13.2.4 Calculated irrigation water needs for the Felicity Pilot Area ............................ 58
13.2.5 Future and potential water needs .................................................................... 60
13.3 Irrigation Sector Study – Concluding Remarks ....................................................... 63
14. OPTIONS FOR IRRIGATION .................................................................................... 66
14.1 Introduction ............................................................................................................. 66
14.2 Possible irrigation water resources ......................................................................... 66
14.3 Irrigation system in the Felicity Area – assumptions .............................................. 73
14.3.1 Irrigation efficiency .......................................................................................... 73
14.3.2 Irrigation ponds ................................................................................................ 73
14.3.3 Water metering ................................................................................................ 76
14.4 Selection of preferred option .................................................................................. 76
15. SELECTED OPTION ................................................................................................. 81
15.1 Selected water resource option .............................................................................. 81
15.2 Recommendations with selected water resource ................................................... 81
15.3 Considerations with selected water resource ......................................................... 82
15.4 Potential Environmental Impacts and Mitigation Measures .................................... 83
16. DESIGN AND FEASIBILITY STUDY. ....................................................................... 84
16.1 Introduction ............................................................................................................. 84
16.2 Water supply options - technical details ................................................................. 84
16.3 Pumps, pipes and ponds ........................................................................................ 86
16.3.1 Lay-out and nomenclature ............................................................................... 86
16.4 Water distribution – organisation and management ............................................... 91
16.4.1 General ............................................................................................................ 91
16.4.2 Irrigation .......................................................................................................... 91
16.4.3 Drainage: (ground) water and salinity control .................................................. 93
16.5 Design .................................................................................................................... 96
16.5.1 System layout .................................................................................................. 96
16.5.2 Pipe system design ......................................................................................... 96
16.6 Tender documents and contracts ........................................................................... 97
16.7 Operation and maintenance ................................................................................... 97
16.7.1 Cost of operation and maintenance ................................................................ 97
16.8 Recommendations related to design issues ........................................................... 98
16.9 Zoning ..................................................................................................................... 98
16.9.1 Economic Feasibility, Cost for Water, Farmers Involvement ........................... 98
16.9.2 Economic Feasibility ........................................................................................ 98
16.9.3 Cost of Water .................................................................................................. 99
16.9.4 Farmers Involvement ..................................................................................... 100
16.10 Funding of the Implementation of the Felicity Irrigation Project ........................ 100
17. CONCLUSIONS AND RECOMMENDATIONS ....................................................... 101
REFERENCES ................................................................................................................... 103
ANNEXES ........................................................................................................................... 105
LIST OF ANNEXES
ANNEX 1: Map of the Felicity Project Area
ANNEX 2: Activities of supporting stakeholders
ANNEX 3, Farmers consultations, rapid appraisal
ANNEX 4: Drainage and flooding
ANNEX 5: International experiences with water users associations
ANNEX 6: Characteristics of aquifers and well fields in the Central Sands and Limestone
ANNEX 7: Water quality in the Caparo River
ANNEX 8: Test results of water samples from Project Area
ANNEX 9: Guidelines for interpretation of water quality for irrigation
ANNEX 10: Irrigation water requirements
ANNEX 11: Design
ANNEX 12: Assignments of consultants, meetings and fieldwork, persons met
ANNEX 13: Terms of reference
ANNEX 14: Work plan and time frame
LIST OF FIGURES
Figure 1: Felicity Project Area, Ravine Sable Sand Pits and proposed location of Mamoral
Dam (source: Environmental Impact Assessment Study, Mamoral Dam and Reservoir
Project, NIDCO) .................................................................................................................... 11
Figure 9.1: Piarco Daily High and Low Temperature ............................................................ 37
Figure 9.2: Rainfall distribution over the months, Couva-Tabaquite-Talparo ........................ 38
Figure 9.3: Trinidad Isohyetal Map ....................................................................................... 38
Figure 9.4: Relative Humidity ................................................................................................ 39
Figure 9.5: Wind Speed ........................................................................................................ 40
Figure 13.1: Felicity Scheme Irrigation Requirements, 2013 and 2050 (mm/month) ............ 61
Figure 14.1: Caparo River, daily discharge at Todds Road, 2001 ........................................ 68
Figure 14.2: Ravine Sable Sand Pits .................................................................................... 69
Figure 14.3: Simulation water requirements WASA and Felicity Irrigation at Ravine Sable
Sand Pits, 2013 ..................................................................................................................... 72
Figure 14.4: Simulation water requirements WASA and Felicity Irrigation at Ravine Sable
Sand Pits, 2050 ..................................................................................................................... 72
Figure 14.5: Dynamic water level on-plot pond during the year, situation 2013 ................... 75
Figure 14.6: Dynamic water level on-plot pond during the year, situation 2050 ................... 75
Figure 16.1: Location of the Felicity project area .................................................................. 84
Figure 16.2: Large Buffer Ponds on Caparo River, map ....................................................... 86
Figure 16.3: Large Buffer Ponds on Chandernagore River, map ......................................... 87
Figure 16.4: Simulation water level at Ravine Sable Sand Pits - 2013 ................................. 90
Figure 16.5: Simulation water level at Ravine Sable Sand Pits - 2050 ................................. 90
LIST OF TABLES
Table 1: Climate change, impacts and mitigation measures ................................................ 15
Table 2: Evaluation matrix of options (dry season) for irrigation water resources ................ 17
Table 11.2: Test results of water samples from the Project Area ........................................ 48
Table 11.3: SAR-values of water samples taken in the Project Area ................................... 49
Table 11.4: Water quality matrix related to irrigation for samples taken in the Project Area. 50
Table 13.1: Water Availability per Watershed Based on 1999 WRMS ................................. 56
Table 13.2: Irrigation water volume for Felicity Pilot irrigation scheme, 2013 ....................... 59
Table 13.3: Crop Water Use Parameters - Climate Change adjusted .................................. 61
Table 13.4: Climate Change Adjusted Reference Crop Evapotranspiration for 2050 ........... 62
Table 13.5: Irrigation water volume for Felicity Pilot irrigation scheme – 2050 ..................... 62
Table 14.1: Irrigation water requirement (including losses) .................................................. 74
Table 14.2: Evaluation matrix of options (dry season) – irrigation water resources ............. 77
Table 15.1: Potential impacts & mitigation measures related to preferred options for source
water and conveyance .......................................................................................................... 83
Table 16.1: Preliminary Make up of Secondary Units. .......................................................... 87
Table 16.2: Capacity LBP and pumps .................................................................................. 87
Table 16.3: Preliminary set-up of supply and distribution systems ....................................... 88
Table 16.4: Filling of On-Farm Ponds ................................................................................... 92
ABBREVIATIONS
AIP Agricultural Incentive Programme CARDI Caribbean Agricultural Research and Development Institute CARICOM Caribbean Community CARIRI Caribbean Industrial Research Unit CACC County Agricultural Consultative Committee CGI Caroni Green Initiative EMA Environmental Management Authority EU European Union FAO Food and Agriculture Organisation GDP Gross Domestic Product GIS Geographic Information System GoRTT Government of the Republic of Trinidad and Tobago MFP Ministry of Food Production MPD Ministry of Planning and Development MPHE Ministry of Planning, Housing, and Environment NAS National Sugar Adaptation Strategy NEP National Environmental Policy N S M G National Strategic Management Group RSSP Ravine Sable Sand Pits SP Sugar Protocol T&T Trinidad and Tobago TTWS Trinidad and Tobago Water Services UWI University of the West Indies VSEP Voluntary Separation of Employment Programme WRA Water Resources Agency WASA Water and Sewerage Authority WRMS Water Resources Management Strategy WTO World Trade Organization a.s.l. above sea level aq. aquifer b.g.l. below ground level EC electrical conductivity igpm imperial galon per minute mg/l milligrams per litre m
3/d cubic metre per day
m3/hr cubic metre per hour
mm millimetre m
3/s cubic metre per second
μs micro-Siemens
msl mean sea level msy maximum sustained yield s drawdown T-value Transmissivity-value Q yield Q/s Specific Capacity Conversions
1 ft = 0.305 m 1 gallon UK = 4.55 litres
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EXECUTIVE SUMMARY
The Felicity Irrigation Project
The EU-financed project ‘Water Management and Irrigation Assessment and Development on the
Felicity Site, Central Trinidad’, also referred as the ‘Felicity Irrigation Project’, is a project initiated in
the context of the National Adaptation Strategy (NAS). The Project has been implemented in
conjunction with the Ministry of Food Production (MFP), and the Water and Sewerage Authority
(WASA/WRA)). The Project Area consists of 1300 acres in the former sugar lands of Caroni Ltd and is
presented in Annex1, and in Figure 1.
For the Project data were collected in the field of irrigation, hydrology, hydrogeology, meteorology,
soils, and water quality. Also environmental, socio-economic, and policy data were incorporated.
Satellite imagery was used, fieldtrips undertaken, water samples taken and analysed, and Lidar data
(derived digital elevation model/DEM) interpreted. The Project has been carried out in the period mid-
May till mid-September 2013.
Figure 1: Felicity Project Area, Ravine Sable Sand Pits and proposed location of Mamoral Dam (source: Environmental Impact Assessment Study, Mamoral Dam and Reservoir Project, NIDCO)
Objectives of the Project
The general objective of the assistance o f t h e E U to the Government of Trinidad and Tobago
i s to mitigate the adverse effects of restructuring their sugar sector. The global objective of the
Project was to identify options for irrigated agriculture for the Felicity Agricultural site in Central
Trinidad. A preferred option was to be recommended and designs for irrigation and drainage
infrastructure prepared, including contract and tender documents.
The irrigation study, presented in current report, will serve as an approach as to the way forward for
other sites identified within these former sugar growing areas. Is the first phase of three phases and
includes a feasibility study with design and tender documents. The second phase will be the
implementation of the proposed option for irrigation, and the third phase will be to duplicate the design
at other former Caroni sugar lands. In other words: the objective is to develop a feasible and viable
Caparo River Ravine Sable Sand Pits
Felicity Project Area
Proposed Mamoral Dam
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plan for irrigated agriculture for the Felicity Project site and to use this plan as a model for other areas
in Trinidad.
Stakeholders
The identified primary recipient stakeholders in the project are:
Ex Caroni employees having a lease on 2-acres of land and working their own land. Secondary recipient stakeholders in the Project Area are:
Ex Caroni employees having a lease on 2-acres of land, not working on their land.
Farm labourers, hired to work in the Felicity agricultural area.
Entrepreneurs who deliver agricultural inputs like farm tools, fertilizer and agro-chemicals, but also entrepreneurs who offer mechanised tilling, using their own tractor and equipment and labour for a fee.
Entrepreneur farmers who sublease the agricultural land leases from ex Caroni employees to put together larger scale farming enterprises.
Supporting stakeholders in the Felicity Irrigation Project are the ministries and authorities that have a relation with agriculture and water resources management (chapter 5 in main report).
Needs Assessment, Water User Associations (WUAs)
For the needs assessment concerning the Felicity Project Area information was gathered during
meetings, field visits, and consultations, including the rapid appraisal that was conducted in the
Project Area (chapter 7, Annex 3). The needs in the Felicity Project Area, as expressed by the
stakeholders, including the recipient stakeholders, are as follows:
more water;
irrigation water;
better lease conditions;
better infrastructure
better security;
a famers association;
additional training;
market system;
store houses, cooling facilities.
In many places word wide not all people pay their water bills. The same applies for payment for
irrigation services. In general, and also in the Felicity Project Area, famers indicated their willingness
to pay for a proper irrigation system, but they would like to see first that the service is working well
before starting to pay. Famers associations, or water user associations (WUAs) have not been
established yet in the Felicity Project Area. WUAs are often formed by groups of farmers, who have
shared interests in the demand for and the management of irrigation water. WUAs can be large or
small, and may be formally constituted (as an NGO), or by informal arrangement. Before a farmer’s
association is established certain aspects need to be studied, such as: objectives of the WUAs, areas
of responsibility, and structure of the organisation (chapter 7).
Potential Positive Impact on the Socio-Economic Situation
Turning the former sugar lands of Caroni (1975) Ltd. in cultivated and irrigated farm lands, will have a
positive influence on the regional socio-economic situation. The arrangement to use the property for
agriculture shall generate positive economic returns, resulting in increased rural income and creation
of employment. When the irrigated farm lands prove to be profitable workers will be attracted to these
areas. These farmers will then produce and supply a wide range of fresh agricultural products, which
will most likely adjust prices downward. Consumers may benefit from healthier agricultural products at
lower prices. Also the issue of food security will be enhanced.
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Environmental Considerations and Climate Change
Due to irrigation practises several components of the physical and human environment may be
affected, whether this is negative or positive. A strong positive impact is expected from the
introduction of irrigation on the socio-economic situation. Potential negative environmental impacts of
irrigation systems may be caused by agricultural runoff on surrounding rivers and downstream users,
affecting water, soil, flora and fauna (biodiversity), landscape, and human health (pesticides
&fertilisers, re-use of waste water).
In the design of the preferred option for irrigation services in the Felicity Project Area, climate change
as an outside effect, has been taken into account. For Trinidad and Tobago, climate change experts
believe that in the future longer, drier summers, shorter and more intense rainy seasons, and a
potential increase in sea level will occur. Because of expected higher frequency and intensity of
tropical storms, more flooding in low lying areas is expected.
In brief, the Caribbean region global climate change (GCC) is expected to result in:
a more hostile regional climate;
rise of temperature of about 0.2 °C per decade;
higher frequency and intensity of tropical storms and hurricanes;
more severe droughts;
rising sea level. Climate change results in environmental and socio-economic impacts, which partly can be mitigated by specific measures. Major impacts and mitigations measures related to agriculture are presented in Table 1. Table 1: Climate change, impacts and mitigation measures
Climate Change Impacts of climate Change Mitigation Measures
Rise of temperature More intense rainfall, higher frequency and intensity of tropical storms and hurricanes More severe droughts Rising sea levels
Lower crop production Higher frequency of floods; more severe floods Soil erosion, hardening of soils Coastal erosion, salt water intrusion, flooding
Development of crops that can grow under higher temperatures, proper water management Good drainage systems, proper water basin management, reforestation, soil conservation Soil conservation, planting trees, wind breakers, crop rotation, mulching, proper water management Protection of coasts by wetlands, mangrove forests, dikes, producing salt tolerant crops
Possible Irrigation Water Sources
The consultants have identified four possible sources for dry season irrigation water supply:
1. The Caparo River in the project area;
2. Groundwater abstracted in or close to the project area;
3. Upstream reservoirs and conveyance of water to the project area:
a. Large existing, flooded mining pits east of the project area, adjacent to the Caparo River;: the
Ravine Sable Sand Pits (RSSP)
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b. The Caparo River dam (Mamoral), formerly only planned for flood protection, now under
consideration as multi-functional reservoir;
c. Abels Clay Pit, now still being mined under a current license.
4. Treated wastewater re-use and drainage water re-use:
a. Conveying treated wastewater from outside the project area directly to the project area;
b. Within the project area, by collecting the outflow /drainage and re-using it by mixing it with the
selected irrigation water source(s) – closed loop
Combinations of more than one of the above water sources can (and have to) be considered.
Evaluation of options for Irrigation Water Sources
To evaluate the options and to come to the most optimal mix of water resources an evaluation matrix
of the different options has been prepared, Table 2. In this table a list of different criteria is set against
the various sources for irrigation water. The matrix provides an overview of advantages and
disadvantages of the different possible water resources. An analysis and evaluation of options, and a
selection of a feasible solution, can only take place based on an overall view of combinations of
resources. It is necessary to use those resources in such a way that the most positive characteristics
are combined in an optimal mix.
Another important consideration that may not be clear from the matrix is that it is recommended to
work as much as possible with the infrastructure that is already in place. Making large changes will be
expensive, and disruptive to farmers who are already working the land, and even partly irrigating the
land. By adapting, improving and adding to their present practices the transition to the new system
can be expected to be much easier, as the acceptance will be much higher. It is imperative to involve
the farmers and other beneficiary stakeholders during all steps of the decision making process.
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Table 2: Evaluation matrix of options (dry season) for irrigation water resources
Resource
Criterion
weight
Caparo
River
Ground
water1
Sand
pits,
pipes
Mamoral
Reservoir,
pipes
Sand pits
Caparo,
River
Mamoral
Reservoir,
Caparo
River
Water availability2 2x ++ 0 ++++ ++++ ++++ ++++
Other claimants 1x + + - - - - - - - -
Water quality 1x - - ++ ++ ++ ++
Salt water intrusion 1x o - - ++ ++ ++ ++
Robustness 1x - + o o o o
O&M costs 1x - o - - - -
Environmental
impact 1x - - ++ ++ ++ ++
Conveyance losses
(primary system) 1x + + ++ ++ - - - -
Obstacles for
construction 1x + o - - - - - -
Cost 1x o + - - - - - - - -
Total3 + o +++++ +++++ ++ ++
Key: - - negative; - somewhat negative; o neutral, no effect; + somewhat positive; ++ positive.
Based on the description of the various identified water resources the following can be concluded:
1. Non-viable resources
- Groundwater is not considered a promising source for irrigation water in the Felicity area. The
consultants will not consider groundwater in the mix, for now.
2. Inside the Felicity project area
- Ponds are already constructed on many plots, and are easily and cheaply constructed. The
concept is clear, though the farmers feel that the capacity is too small and the ponds take too
much arable land, especially when they are dry. The study suggests that ponds do have an
essential function in safeguarding irrigation in the Felicity Area, both during the rainy season to
bridge dry spells and as buffers to store and distribute irrigation water during the dry season. The
criticism of the farmers can be countered if a single pond is used for one plot and if the ponds are
replenished from an outside source during the dry season. The land loss, at about 5%, is
acceptable considering the advantages of irrigation and increased water security. The total
capacity of the ponds is 1 Mm3 for the entire Felicity area. The consultants recommend using the
ponds (individual or for groups of plots), and construction of ponds for each of the plots that are
to be irrigated. This is in line with the policy of the Ministry of Food Production.
1 Groundwater has a total score of 0 because it can be neglected. Water availability cannot be
negative. 2 4 ++++ can be awarded as this criterion has twice the weight
3 Total: simply add all +, - and o, valued at 1, -1 and 0.
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- Directly linked to the above it follows that an infrastructure needs to be constructed that can
replenish the ponds. A network of rigid (preferably buried) pipes, a network of irrigation channels,
or a combination of the two will be required, to carry the water from the intake location to the
ponds. This system can be operated on a rotational, non continuous basis, given the fact that the
ponds hold a buffer of at least 6 weeks of irrigation water. The consultants prefer a system of
(buried) pipes, especially since this proves to be the preferred method used in other areas.
- A method to measure the amount of irrigation water used by an individual farmer is needed.
Outside the Felicity project area
When considering the above, possible sources of water to supply the ponds are to be identified.
Looking at the matrix of Table 2 there are two viable options, described below.
The Caparo River, but only after rainfall has created enough run-off to flush the accumulated
pollutants and dilute any that are being added to it. For this four things are needed:
1. A weir or weirs are to be constructed in the Caparo River, and possibly basins need to be
constructed to allow pumping. Such basins hold relatively small amounts of water;
2. Large ponds to fill quickly, along the river (buffer of peak flow);
3. A number of large capacity pumps to quickly fill the large ponds when a suitable discharge peak
occurs. The pumps have to be big because the suitable discharge peaks last only a few days at
maximum.
4. This needs a knowledgeable and adequate management, to decide when to operate the pumps.
The operator may get a warning based on rainfall upstream, from one of the rainfall stations in or
near the head of the basin, or through the meteorological services division. An operations
procedure cannot be given as this depends on the actual irrigation water requirement, which will
be different based on actual rainfall and water use.
The drawbacks of using the Caparo River as resource are twofold:
1. The cost of the pumps and the complexity of operation;
2. The residual level of pollution, and the unreliable, irregular and intermittent flow.
A clear advantage is that all needed infrastructure can be built within the project boundaries, so it
is easily controlled and managed by a farmers representative body. Building the infrastructure is
relatively simple and straightforward, but expensive.
The Mamoral reservoir and the Ravine Sable Sand Pits. Both sources would have the same
advantages and disadvantages, and can and even should be operated as one system. At this
moment it is not certain that the Mamoral dam will be built. The Ravine Sable Sand Pits appear to
have enough water for both the Felicity irrigation requirement as well as to cover the WASA demand
for domestic water supply.
For the sake of this discussion it is assumed that water can be made available from the Ravine Sable
Sand Pits. If the Mamoral Dam is built a means to convey the water to the Sand Pits needs to be
decided upon (pipe, or by releasing it in the Caparo River bed). Also, an inlet and cross dam needs to
be constructed in the Caparo River next to the sand pits divert the river water in a controlled manner
into the sand pits. It is assumed that such works will be constructed as a part of the flood control and
mitigation measures currently being studied by the Caparo River Basin project; they will be
considered only in a qualitative manner by the Felicity irrigation project.
While the active storage of the Ravine Sable Sand Pits is not sufficient to cover all the requirements
of the Felicity area, it will also collect runoff during rain in the dry season, increasing the total water
yield. In combination with optimal use of the ponds in the Felicity area the water from the Ravine
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Sable Sand Pits is expected to cover the irrigation water requirements for the Felicity area (NIDCO,
2013).
A method to convey the water from the sand pits to the Felicity irrigation intake is needed. There are
two options:
1. Use the Caparo River as conduit by pumping the water from the sand pit back into the river. This
appears to be a very elegant solution: the entire infrastructure to utilise the water of the Caparo
River during the rainy season is the same as for the dry season. However, the cost of pumping
for this option is significant.
2. Build a pipeline, estimated length up to 10km, and use the Ravine Sable Sand Pits as buffer.
Using the Caparo River as conduit:
Advantages
- The entire infrastructure at the Felicity area can be used both in the dry and rainy season,
although the buffer (intake basins) capacity may have to be increased to avoid loss of water
through spillage and a number of large pumps are needed;
- The required ecological flow will add to the irrigation water volume available at the intakes at the
Felicity area.
- Implementation and construction time are relatively short (easily within one dry season).
Disadvantages:
- Cost for pumps, electricity grid, transformers.
- Losses, mostly from legal and illegal abstraction from the Caparo River between the sand pits
and the Felicity inlet, are expected to be higher than for a pipeline
- The water will collect polluted effluent, decreasing the water quality on its way to the Felicity
Area.
- Operation of the pump at the RSSP has to be coordinated with the pumping at the Felicity
intake(s), taking into consideration the travel time through the river
- Leakage beyond the Felicity inlets may occur if not all released water is pumped. However, a
limited ‘ecological flow’ is required anyway.
Building a pipeline as conduit:
Advantages
- Losses are expected to be low.
- Water quality will not be decreased by lateral inflows
- The system will deliver water at pressure to the Felicity area, facilitating easy distribution in the
secondary system. It will be possible to construct a fully pressurised system delivering the water
to the ponds, with relatively small pumps as the system can convey water 24/7 (with ‘smart’
operation and management);
- This system could possibly be implemented without the ponds, though management of a system
without ponds is very complex and the buffer will be cancelled, significantly increasing the
required dry season flow from the RSSP reservoir. Preliminary calculations (NIDCO, 2013) show
that this is not feasible. Management of this system and both investment and O&M costs will be
higher, due to irregular demand. This approach is deemed not viable by the consultants.
Disadvantages:
18
- Costs are significant, but may in the end be lower than using the Caparo River bed as conduit,
due to the huge difference in required pump capacity. Also, pumps need to be replaced while the
pipeline is probably good for more than 50 years.
- Implementation and construction will be time-consuming. A detailed survey of the right of way is
required, followed by a detailed design. Access to land and the actual right of way has to be
purchased where this is not government owned. A project like this will require tendering
procedures that are much more demanding and time-consuming than for the construction of a
simple pump unit.
Conclusions
The consultants concluded that there are two viable options to provide irrigation water to the Felicity
Pilot area. Both include the individual ponds and a system to replenish these ponds.
Option 1: Source water from the Ravine Sable Sand Pits, possibly in combination with the Mamoral
Dam Reservoir, conveyed to the Felicity Pilot Area using the Caparo River. This will include intake
works and a large number of big pumps on the Caparo River within the project area. During the rainy
season the natural flow of the Caparo River can be utilized to replenish the ponds. During the dry
season water can be released (pumped) from the Ravine Sable Sand Pits into the Caparo River bed.
Option 2: Source water from the Ravine Sable Sand Pits, possibly in combination with the Mamoral
Dam Reservoir, conveyed to the Felicity Pilot Area using a pipeline. This will mean that the intake
works in the Caparo River may not be needed, and water is available at the intake to be distributed to
the ponds under pressure. This option has the advantage of offering 24/7 supply, resulting in relatively
small flow rates (maximum 170-175 l/s) which can be handled with small pumps and a pipe diameter
of about 50 cm (20 inch).
Closed loop system: Adding the closed loop re-use system to either of the above options will reduce
the required amount of ‘fresh’ irrigation water. The effects of applying this interesting concept will have
to be modelled; a rough estimate can probably and possibly be done quickly. Introduction of the
closed loop system has a clear and negative effect on leaching requirements. It is recommended to
implement this only after an additional study into the effects on the soil salinity and the economics.
See also Chapter 16 on salinity and risks of salinisation.
The consultants suggest that Option 1 and Option 2 are considered as Phase 1 and Phase 2. It is
recommended to start with Option 1 for a limited number of plots (100-120) in the Felicity area, and
then start the preparations for building the pipeline. The process of detailed survey, detailed design,
tendering, possibly expropriation and compensation (along the right of way), construction and delivery
can then take place without delaying the introduction in the Felicity Area.
19
1. INTRODUCTION
Following a World Trade Organisation (WTO) ruling, the EU announced that it would phase out the
Sugar Protocol, under which African, Caribbean and Pacific sugar producing former colonies received
preferential prices. To facilitate this, the EU would provide funds to those Sugar Protocol countries
that choose to diversify away from the sugar business within a structured framework, the EU-
approved National Sugar Adaptation Strategy (NAS, submitted 2007). These developments made
Trinidad and Tobago to initiate in 2003 a strategy to restructure its sugar industry.
The general objective of the assistance of the EU in the sugar sector, is to mitigate adverse effects
caused by the changed situation, based on the decision o f t h e EU Council of Ministers to phase
out the Sugar Protocol (2005). Since 2008 the EU has been supporting the Government of Trinidad
and Tobago (GORTT) with restructuring former sugar lands, focusing on infrastructure, diversification
of agricultural lands, and reintegration of former employees of Caroni (1975) Ltd, the country’s state
owned sugar manufacturing company.
The Felicity Irrigation Project
The EU-financed project ‘Water Management and Irrigation Assessment and Development on the
Felicity Site, Central Trinidad’, often referred to in current report as the ‘Felicity Irrigation Project’, or
‘the Project’, is a project initiated in the context of the National Adaptation Strategy. The Project has
been implemented in conjunction with the Ministry of Food Production (MFP), and the Water and
Sewerage Authority (WASA). The Project area consists of 1300 acres in the former sugar lands of
Caroni Ltd, The location has been indicated as the Felicity Site, and is presented in Annex1, Figure
1.1, and in Photograph 1.1.
In the Inception Report for the Project a 15 steps Approach and Methodology (based on the Terms of
Reference, Annex 13) was presented, on which a Work Plan (Annex 14) was built with 25 activities
that would lead to the fulfilment of the assignment.
For the Project data were collected in the field of irrigation, hydrology, hydrogeology, meteorology,
soils, and water quality. Also environmental, socio-economic, and policy data were incorporated.
Satellite imagery was used, fieldtrips undertaken, water samples taken and analysed, and Lidar data
(derived digital elevation model/DEM) interpreted.
The Project has been carried out in the period mid-May till mid-September 2013 by a HTSPE / EPRD
Consulting Team, comprising of Drs. Frank de Zanger (Team Leader, Water Resources Management
Expert), Ir. Bob Pengel (Water Resources Development Expert), Ir. Frank van Berkom (Hydrologist)
and Mr. Luis Arturo Celis Velasco Msc (Hydrologist).
20
Photograph 1.1: The Felicity Project Area
21
2. OBJECTIVES OF THE PROJECT
The general objective of the assistance o f t h e E U to the Government of Trinidad and Tobago
i s to mitigate the adverse effects of restructuring their sugar sector.
The global objective of the Project was to identify options for irrigated agriculture for the Felicity
Agricultural site in Central Trinidad. A preferred option was to be recommend and designs for
irrigation and drainage infrastructure prepared, including contract and tender documents.
The specific objectives of the Project were:
Assess the present situation with respect to irrigation and drainage development at the
Felicity site and assess ongoing water resource projects in the former sugar lands.
Review the existing institutional arrangements for water resources development and
management.
Identify a range of options for the development of sustainable water management (irrigation
and drainage) in the Felicity area, with recommendations for a preferred option.
Prepare design and contract documents for the implementation of the preferred option,
including irrigation, water supply & delivery, wastewater treatment & water reuse (if relevant)
at the Felicity site.
In the ToR the expected results have been formulated as follows: ‘Detailed designs which would allow
for implementation of a communal large scale irrigation system at Felicity, encompassing
approximately 1300 acres, which will serve as an approach as to the way forward for other sites
identified within these former sugar growing areas.’
The irrigation study, presented in current report, is the first phase of three phases and includes a
feasibility study with design and tender documents. The second phase will be the implementation of
the proposed option for irrigation, and the third phase will be to duplicate the design at other former
Caroni sugar lands. In other words: the objective is to develop a feasible and viable plan for irrigated
agriculture for the Felicity Project site and to use this plan as a model for other areas in Trinidad.
22
3. OVERVIEW OF THE NATIONAL SUGAR ADAPTATION STRATEGY (NAS)
3.1 The National Sugar Adaptation Strategy (NAS)
The Government of the Republic of Trinidad and Tobago (GORTT) has been restructuring the
sugar sector since 2003. On March 5th 2007, the National Sugar Adaptation Strategy ( N A S ) was
submitted to the European Union (EU), as a response to the decision by the EU Council of
Ministers (November 24th, 2005) to end the support to the sugar industry (EU Regulation
266/2006). The NAS is a sector policy document that was developed in the context of Vision 2020, a
wider national development agenda, and was based on the Government’s policy to dissociate
from sugar and to end subsidies to the sugar industry.
In 2006 the European Union facilitated the preparation of the National Sugar Adaptation Strategy.
It was funded under the Accompanying Measures for Sugar Protocol Countries (AMSP). The NAS
was a consequence of the decision and actions of the Government of Trinidad and Tobago t o
reform the sugar sector in 2003. Caroni (1975) Limited, the country’s state owned sugar
manufacturing company closed down farming sugarcane and manufacturing s u g a r i n 2 0 0 3 .
A new entity called the Sugar Manufacturing Company Limited was formed, which continued to
produce raw sugar from cane supplied by private farmers from 2003 until 2007. In 2007 all production
of raw sugar ceased.
The NAS is based on the principle that any future activity in the sector should be private sector
and based on sustainable business models. The NAS outlined three strategic objectives:
options for continued sugarcane farming, which would include the exploration of alternative
uses for sugarcane;
diversification into other food crops;
minimisation of socio-economic and environmental impacts.
The Cabinet of the GORTT has overall responsibility for the implementation of the National Sugar
Adaptation Strategy. A technical sub-committee, coordinated by the Ministry of Agriculture Land and
Marine Resources (MALMR), was established in 2006 for the oversight and coordination of the NAS.
In addition, several government ministries hold direct responsibility for implementing elements of the
NAS, including: The Ministry of Finance, The Ministry of Trade and Industry, The Ministry of
Agriculture, Land and Marine Resources, The Ministry of Energy and Energy Industries, The
Ministry of Public Utilities and the Environment, and The Ministry of Social Development.
While several institutions were responsible to faci l i tate the reform, including support for
agriculture, housing, industrial estates, training & entrepreneurship, there was no common
organization charged with a bid to influence policy decisions on the reform. To solve the institutional
overlap, the National Strategic Management Group ( N S M G ) was created in 2008, acting under
the purview of the Office of the Prime Minister as Project Coordination Unit, and taking up
responsibility for the successful management and implementation of the National Sugar Adaptation
Strategy.
3.2 Caroni (1975) Limited
Caroni (1975) Ltd. is the former state owned sugar company for Trinidad and Tobago, which was
nationalized from the Tate and Lyle Sugar Company. The company had ac t i v i t i es in cane
cutting, cultivation, processing (2 sugar mills, 1 distillery), transportation, administration and non-
sugar operations. Caroni (1975) Ltd. played a major role in the economic and political life of the
country. Caroni’s historical and financial evolution i n f l u e n c e d a large c e n t r a l area in
Trinidad. Several towns and villages relied on the company for growth, nutrition and economic
activities, including the country’s second city of San Fernando and the towns Couva and
Chaguanas. The company provided support to private farmers and diversified into several agricultural
activities, including citrus orchards, rice cultivation, cattle breeding, and aquaculture. Despite
23
substantial property holdings, Caroni (1975) Ltd. was independently not profitable and the sugar
industry required substantial subsidies from the state. The Government of Trinidad and Tobago
decided to close Caroni (1975) Ltd. in 2003, and developed a National Sugar Adaptation Strategy
(NAS, chapter 3.1), that provided support to displaced workers and provided land for agricultural,
residential, and industrial development.
The impact, caused by the sudden elimination of the sugar industry w a s
c o n s i d e r a b l e . The most significant socio-economic impact of the government’s decision to
reform the sugar industry was the laying of of almost 10,000 employees f r o m the state-owned
sugar enterprise. In 2003, employees of Caroni (1975) Ltd. were offered compensation in the
form of a Comprehensive Voluntary Separation Package (VSEP). This opportunity provided
alternatives for ex Caroni workers by assisting them and their dependents in the transition from
employee to owner, lessee, investor or entrepreneur. Also two acre plots of agricultural land and
residential lots were included in the separation package. In addition, employees were encouraged
to take free training in their area of choice. According to reports to a ministerial committee in
November 2006, 82% of the former employees ( 7,248) accepted the lease of 2-acre agricultural
and housing plots. A Caroni Agricultural Lands Project Team (CALP) has developed infrastructural
works on several estates where these plots were located.
3.3 Assistance from the EU
The general objective of the assistance o f t h e E U in the sugar sector is to mitigate the
adverse effects of the restructuring activities in the former sugar lands. The EU Council of Ministers
decided to phase out the Sugar Protocol starting in 2006, while supporting the GORTT in the
realization of the priorities stated i n the country’s National Development Plan.
In this framework, the EU strategy supports two of the Strategic Objectives of the NAS:
Promoting economic diversification at former sugar dependent areas (exit strategies for sugar
farmers and sugarcane workers, who choose to leave the industry; improving the
environment for economic diversification).
Addressing broader impacts related to social, environmental, community and area-based
issues (maintaining environmental stability; providing sustainable social and economic
support related to the socio-economic effects of transitioning out of the sugar industry).
Since May 2008, an In ter -Min is ter ia l Commit tee, moni tors the implementation of the
National Sugar Adaptation Strategy. Regular reports are submitted to the EU Delegation on the
progress of the implementation of annual financing agreements.
24
4. RELEVANT PROJECTS AND PROGRAMMES
A project that has definitely implications, and provides possibilities, for the ‘Felicity Irrigation Project’ is
the ongoing ‘Caparo River Basin Flood Mitigation and Water Supply Project’. The ‘Caroni Green
Initiative’ by Caroni (1975) Limited is an important programme that is directly related to the
management of the former Caroni sugar lands and thus of concern for current ‘Felicity Irrigation
Project’. Furthermore, there is the ‘Agricultural Green Initiative’, an incentive programme launched by
the Ministry of Food Production, that in broader context might be of importance for the Felicity former
sugar lands.
4.1 Caparo River Basin Flood Mitigation and Water Supply Project
An important project being carried out east of the Project area is the Feasibility Study and Conceptual
Design for the Caparo River Basin Flood Mitigation and Water Supply Project (Royal Haskoning DHV,
Deltares, Client NIDCO). This Caparo Water Basin Study includes the management of large former
sand mining pits (Ravine Sable Pits), which have filled with water after a heavy flood in the Caparo
River. Although the water level dropped at first for about 5-6 meters, after that the water level
stabilised more or less. The reason for the stabilisation is probably the ‘natural’ lining of the pits by
fine silt and some clay. Of course the idea was born that the pits could be used to catch future floods
of the Caparo River, but also to store water. The water could then be used for water supply, but also
for agriculture, making it an excellent example of an Integrated Water Resources Project. The volume
of water that could be stored in these pits is estimated at 1.6 - 1.7 million m3. In the future a
connection is foreseen between the sand pits and the Caparo River, so that water can be taken in
during rain but in fact as required. Also a dam (Mamoral dam) is planned a few km’s upstream of the
sand pits, which would complement the function of the sand pits (Figure 1.1).
Figure 1.1: Felicity Project Area, Ravine Sable Sand Pits and proposed location of Mamoral Dam (source: Environmental Impact Assessment Study, Mamoral Dam and Reservoir Project, NIDCO)
Ravine Sable Sand Pits
Proposed Mamoral Dam
Dam
Felicity Project Area
Caparo River
25
Ravine Sable Sand Pits
The Ravine Sable Sand Pits, with their large storage of water of good quality, taken upstream from
the Caparo River, could play a major role in providing irrigation water for the Felicity Site and other
irrigated lands in the former Caroni sugar areas. It’s possible role in one of the options for the
provision of irrigation water is explained in the chapter on preferred options
In fact one large sand pit had filled with water. The pit has a depth of about 27 m below ground level
(b.g.l) and the water level in the beginning of August was approximately 20 m b.g.l. The pit had filled
with about 7 m of water, which level is more or less stable. The ground level around the sand pit –
also the level of Caparo River – is approx. 30 above sea level (a.s.l.), the water level in the pit is about
20 m a.s.l. and the Felicity Project Area has a level of about 8 m a.s.l. If water for irrigation would be
used from the sand pit, then (with levels as described) the water need to be pumped 10 m high and
could be transported from a level of 30 m a.s.l. to 8 m a.s.l. Although the distance from the sand pit to
the Project Area is about 10 km, gravity will help to transport the water.
A fieldtrip was undertaken to the sand mining pits on August 3rd
and discussions were held on site
with the Team Leader of the Caparo River Basin Project, other team members and a representative of
the MFP.
4.2 Caroni Green Initiative (CGI)
A programme relevant for the agricultural development of the Felicity Irrigation Project is the ‘Caroni
Green Initiative’ (CGI), a business model developed by the GORTT and Caroni (1975) Limited. This
shared value business model for food production will bring former Caroni lands under sustainable and
profitable cultivation. The available land covers a total of 5.800 acres, comprising mainly the 2-acre
agricultural plots leased to former Caroni workers, as part of the Voluntary Separation of Employment
Programme (VSEP). The Caroni Green Initiative promotes to bring the idle Caroni farm lands under
cultivation, with the objective of an increase in the domestic food supply. Herewith is the CGI
supporting T&T’s economic diversification. The CGI is a business framework that is supported by the
Government, but does not rely on specific subsidies. At the national level the Caroni Green Initiative
will assist the GoRTT to achieve its objectives for the agricultural sector. Reference is made to
chapter 7, which deals with farmer involvement in the operation and management of the irrigated
agricultural lands.
4.3 Agricultural Incentive Programme (AIP)
The Ministry of Food Production launched in 2011 the revised ‘Agricultural Incentive Programme’, a
programme designed to support the agricultural sectors in T&T. The intention is to improve the
efficiency and productivity of the agricultural sector and to conserve the environment. The incentives
are meant to support farmers to continue and expand their agricultural production and to encourage
the new generation to enter the agricultural sector. The incentives offered are: financial support for
vehicles, water for agriculture, land preparation, machinery & equipment, soil conservation, crops,
protected agricultural systems, guaranteed prices, integrated pest management, post-harvest &
marketing, livestock, agro processing, new farmers (youth in agriculture), security, soil amelioration,
waste management, marine fisheries, and aquaculture.
Concerning investment, the National Food Production Action Plan 2012-2015 outlines the investment
opportunities in the agricultural sector.
26
5. STAKEHOLDERS
5.1 Introduction
The involvement of stakeholders is essential in agricultural programmes and projects. Farmers working in the Felicity area are the most important (recipient) stakeholders. If they are to accept ownership of the project, then they have to be heard and be involved. The setting up of farmers/water users associations has been envisaged, as this social engineering phenomenon is critical to the economic viability and sustainability of the project (chapter 7) It is important to clearly define the recipient stakeholder or ‘farmer’ in the Felicity area. Not everybody who has been allotted a 2-acre agricultural plot is a farmer. However, all these persons have a lease. Some will cultivate the land themselves; other lessees would their land be managed by experienced famers or agricultural entrepreneurs. All of these contributors should be regarded as recipient stakeholders. Subsistence farming is clearly not the objective of the GoRTT, and also does not seem to be the intention of the owners / lessees of the agricultural plots. The second important group of stakeholders are the institutions, which are involved in the National Sugar Adaptation Strategy. These ‘supporting stakeholders’ are involved in the transition process of former sugar workers into other work or livelihoods. Most of the supporting stakeholders are government institution or are organisations clearly linked to the Government of T&T.
5.2 Recipient Stakeholders
The primary recipient stakeholders in the project are:
Ex Caroni employees having a lease on 2-acres of land and working their own land. Secondary recipient stakeholders in the project area are:
Ex Caroni employees having a lease on 2-acres of land, not working on their land.
Farm labourers, hired to work in the Felicity agricultural area.
Entrepreneurs who deliver agricultural inputs like farm tools, fertilizer and agro-chemicals, but also entrepreneurs who offer mechanised tilling, using their own tractor and equipment and labour for a fee.
Entrepreneur farmers who sublease the agricultural land leases from ex Caroni employees to put together larger scale farming enterprises.
5.3 Supporting Stakeholders
Supporting stakeholders in the Felicity Irrigation Project are:
Ministry of Food Production (MFP) - Engineering Division and Agricultural Planning Division.
Water Resources Agency (WRA) as a division of the Water and Sewerage Authority (WASA).
Drainage Division of the Ministry of Environment and Water Resources.
Environmental Policy and Planning Division of the Ministry of Environment and Water Resources.
Environmental Management Authority (EMA).
Caroni (1975) Limited
Water and Waste Water Sector Advisory Committee under the Ministry of Science, Technology and Tertiary Education, which has been mandated to develop Occupational Standards for that sector
National Infrastructure Development Company (NIDCO), responsible for executing flood mitigation and water management projects within various watersheds across Trinidad.
While not mentioned in the ToR and not directly involved in the study, the following additional supporting stakeholders are important for creating an environment that is conducive to successful agricultural entrepreneurship in the Felicity Area and in the former sugar lands in general. These organisations support farmer entrepreneurs by supplying information, extension services, contract farming, knowledge transfer, guaranteed minimum prices, and agricultural credit. Incentives (subsidies) on agricultural inputs are available. Additional supporting stakeholders:
Extension Training and Information Service of the Ministry of Food Production (MFP).
27
National Agricultural Marketing and Development Corporation (NAMDEVCO).
Agricultural Society of Trinidad and Tobago (ASTT)
Trinidad and Tobago AgriBusiness Association (TTABA).
Agricultural Development Bank. The activities of the supporting stakeholders are outlined in Annex 2.
5.4 Stakeholder Contact
Weekly progress meetings were held at the Engineering Division of the Ministry of Food Production in
Centeno, with representatives of the Ministry of Food Production (MFP, Engineering Division &
Agricultural Planning Division), the Water Resources Agency (WRA), the Water and Sewerage
Authority (WASA), and the Drainage Division of the Ministry of Environment and Water Resources.
Farmers in the Felicity Project Area and lessees of the former sugar lands in the Project Area have
been interviewed. Famers were interviewed, working 5-6 km’s East of the Project Area and members
of the last functioning County Agricultural Consultative Committee (CACC) in the region. Also farmers
working in the Felicity Project Area were consulted. A rapid appraisal was carried out, which gave
interesting results. The results are discussed in chapter 7 and presented in Annex 3.
The following institutes and organisations have been visited and consulted:
Extension Training and Information Service Division, Ministry of Food Production, MFP. County Caroni Engineering Division, Chaguanas, Ministry of Food Production, MFP. Environmental Management Authority, EMA. Drainage Division, Ministry of the Environment and Water Resources (NIDCO). Caroni (1975) Limited. Caribbean Agricultural Research and Development Institute, CARDI. Caribbean Industrial Research Institute, CARIRI. Trinidad and Tobago Meteorological Service Division. Town and Country Planning Division, Ministry of Planning and Sustainable Development. Project Office of Royal Haskoning/DHV, concerning Caparo River Basin Study. County Agricultural Consultative Committee, meeting with farmers 5-6 kms East of project
area; Organised by County Caroni Engineering Division, Chaguanas, Ministry of Food Production, MFP.
Meeting and interviews with lessees in the Felicity Project Area.
. A full list of meetings held, fieldwork carried out, and persons met (including details on addresses, tel.
numbers and e-mail addresses) is presented in Annex 12.
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6. EXISTING SITUATION IN THE FELICITY AGRICULTURAL AREA
6.1 Caroni (1975) Ltd. Lands
Of the 76,608 acres of available Caroni (1975) Ltd. lands, 27% (20,319 acres) have been allocated for
sub-division into 2-acre lots for ex-Caroni workers, as a part of the Voluntary Separation, Employment
Packages (VSEP). The Felicity Project area consists of 1300 acres in these former sugar lands. The
location has been indicated as the Felicity Project Area, and is presented in Annex1, Figure 1.1, and
in Photograph 1.1. The Site is a low lying flat area, which slopes gently to the coast, where mangrove
swamps protect the area against the sea at the west side. The government has constructed drainage
channels and provided infrastructure like roads and bridges.
6.2 Land lying fallow
Presently, only about 10% of the area is under cultivation. The reason is that many leases have been
given to persons, who worked for the Caroni Ltd, but were no farmers. Several of them have
attempted farming but failed, because of lack of experience, others never started any activity on their
leased lands. More factors have been cited as obstacles to mobilizing the two-acre agricultural plots
into production, like: long distance of the plots from tenant’s residences, legal restrictions imposed on
the use of the land, and lack of interest of land holders in agriculture. Some beneficiaries were
discouraged after learning that the ownership arrangement with the 2-acre plots is leasehold rather
than freehold, as they thought when they were signing the VSEP. A considerable area is lying fallow
at the Felicity site, but an even larger area outside the Project Area is uncultivated, resulting in a huge
loss of production and revenues. Government policy is clearly to increase agricultural production to
obtain food security.
6.3 Drainage, Flooding and Irrigation
Drainage is well managed in the Project Area. A grid of drainage channels has been constructed,
which drain the land under gravity. The land is not water logged in the wet season and there are no
reports of flooding in the Felicity Project Area. Maintenance is sufficient; once per year the MFP is
cleaning the channels. Because of the well-functioning drainage system, there is no high risk for
salinisation of the soil. The low salinity figures in the existing irrigation ponds (chapter 11.3) confirm
this. Annex 4 provides more information on drainage and flooding in the Project Area and the region.
At present there is no proper irrigation and waste water (re-use) system in the Felicity Project Area.
This is one of the reasons that a large percentage of the land is uncultivated. Farmers need sufficient
water also in the dry season to increase crop production. Unfortunately, access to water for
agricultural purposes has to face competition from domestic, industrial and service sectors, especially
during the periods of drought. This is why a major objective of the Project is to identify options for the
development of a sustainable irrigation and drainage system, with recommendations for a preferred
option.
Irrigation is practised in the Project Area during the dry season, but in a rather primitive way. Farmers
block the rivers with wooden planks and let the river water level rise. Then river water is pumped in
drainage channels, which are sometimes blocked as well. From there the water is pumped through
hoses and spray-pipes to irrigate the land. There is no system in place to re-use irrigation water. The
existing irrigation ponds are not functioning properly at present. Famers told (chapters 6.4 and 7) that
the volume is not large enough (20x20x4.5m). Once the pond is full, it is pumped empty in one day.
Filling the ponds occurs by rain and by pumping of river water. However most ponds are not located
near the river and lack proper water inlets. The soils in the area consist of heavy clay. When the
ponds are dry there is no replenishment from groundwater, although the ponds reach into the
groundwater. This also implies that leakage from the ponds, when filled with water, into the
groundwater is minimal. Crops that are grown by the farmers at present in the Felicity Agricultural
Area are: hot pepper, cucumber, eggplant, cassava, eddoes, occra, corn (limited), pumpkin, and
caralli.
29
6.4 Transfer to Non Subsidised Agriculture
Most vegetables in Trinidad and Tobago are imported. Generally consumers don’t trust local crops,
because in newspapers and magazines is reported that for local produce pesticides and fertilizers are
extensively used and may not be safe to eat. Although in the Felicity Area farmers are practising
Integrated Pest Management, using as much as possible non persistent pesticides, the public is not
aware of it and prefers to buy imported vegetables. It all means a loss of entrepreneurial
opportunities, loss of capacity for national self-sufficiency, and increased vulnerability to food scarcity.
Importation of large amounts of food has increased food prices. This has triggered inflation and is a
burden for the citizens of Trinidad and Tobago in the low income group. However, it also provides
chances for the agricultural sector in T&T, because if food production can be generated in a
sustainable manner and with good marketing, then there is a vast internal market (T&T), profits can
be satisfactory and no subsidies are required..
One of the roles of the Ministry of Food Production (MFP) is to carry out agricultural research, to
develop technology, and to increase agricultural production (MFP Strategic Plan 2010-2015). Vision
2020 states development and modernising farm and agri-food systems to ensure sustained growth
and development in a dynamic environment. The agri-food system must be rapidly transformed into
an efficient and productive sector that is dynamic and competitive and provides food and nutrition
security.
6.5 Needs Assessment
For the needs assessment concerning the Felicity Project Area information was gathered during
meetings, field visits, and consultations, including the rapid appraisal that was conducted in the
project area on August 12th 2013 (chapter 7, Annex 3).
The needs in the Felicity Project Area, as expressed by the stakeholders, including the recipient
stakeholders, are as follows: more water, irrigation water, better lease conditions, better infrastructure,
better security, a famers association, additional training, market system, store houses, and cooling
facilities.
More water
More water is needed for agricultural development in the area. The required volume of additional
water needed could not be revealed. It depends on too many factors. To be able to make a good
living as farmer in the Felicity Area, more water is needed.
Irrigation water
When is expressed that more water is required, it is evident that especially more water is needed in
the dry season. Consequently, irrigation water is needed. It could not be stated how much irrigation
water is required, but in principle the volumes needed to be able to cultivate the land the whole year
round.
Better lease conditions
Lessees clearly expressed that the right to lease the 2-acre plots of the ex-Caroni lands, which is 30
years, is too short. Farmers hope to hand over their cultivated lands to their children or grandchildren
and for that reason would like to have a lease period of 99 years. Preferably, they even would like to
buy the land. A farmer should feel attached to their land; this is a worldwide phenomenon.
Better infrastructure
The government established infrastructure in the Felicity Project Area, like drainage channels, roads
and bridges. However, the famers would like the infrastructure to be improved. Roads need
improvement and proper maintenance; bridges should be repaired (there are holes in it). Drainage
canals are being cleaned each year, but with an irrigation system in place, this might not be sufficient.
30
Better security
Farmers complained that crops are stolen from their fields. The idea is that a gate system might help.
A famers association
The need is felt for a farmer’s association of local famers with a flat and direct organisation structure,
to manage in cooperation an irrigation system and possible to combine efforts for transportation,
storage and marketing.
Additional training
Especially, there is a request for additional and continued training in Integrated Pest Management
(IPM). Farmers are familiar with IPM and buy as much as possible non persistent ‘safe’ pesticides, but
they realise that IPM is evolving and they would like stay informed.
Market system
If the irrigation system in the Felicity Project Area demonstrates to be successful and the concept is
duplicated to other areas in Central Trinidad, then a large market for crops may emerge. A proper
market system should then be in place to be able to pack and transport the produce in a proper
manner and to sell it for a good and compatible price. Even export should be considered.
Store houses, cooling facilities
Related to a market system for packing, transport, and strategic pricing, are store houses and cooling
facilities, where crops may be stored temporarily. A question to be answered then is where these
store houses and cooling buildings should be constructed; near the farm lands or near harbours or air
fields. Probably, the Extension Training and Information Service of the Ministry of Food Production
could facilitate such training.
6.6 Institutional Arrangements for Water Resources Management
The Water and Sewerage Authority (WASA) was established by an Act of Parliament in 1965 to
manage the water and sewerage sector of Trinidad and Tobago. The Water Resources Agency
(WRA) was appended to WASA as a division in March 1976 and is responsible for the management
and control of the Nation’s water resources, including agriculture. An description of WASA’s and
WRA’s objectives and tasks are presented in Annex 2.
31
7. CONSULTATIONS WITH FAMERS, FARMERS ASSOCIATIONS
7.1 The Felicity Project Area
Farmers in the Felicity Project Area and nearby in the region have been consulted about their farming
practises and about the existence of and aspirations for farmers/water users associations.
Famers consultation
On July 9th. farmers were visited living 5-6 kms east of the Project Area in a region where formerly
tobacco was grown (Depot Road). These farmers are members of the last functioning farmers
association in the region, the County Agricultural Consultative Committee (CACC). The CACC, in
which a group of farmers is represented, meets monthly. It is a farmer’s forum; not a legal entity, set
up as a means of communication between farmers and the Ministry of Food Production. There were
plans to set up a RACC, or Regional Agricultural Consultative Committee, to act as a ‘layer’ between
the CACC’s and the Ministry. However, this was never implemented. A short report of the consultation
is provided in Annex 3.
Rapid Appraisal
On August 12th the County Caroni Engineering Division (Chaguanas) of the Ministry of Food
Production organised a consultation meeting with eight famers, who work in the Felicity Project Area,
The intention was to obtain through a rapid appraisal insight in what the famers do, what their wishes
are, and what problems they face. A rapid appraisal is a data collection method, aimed at supplying
information in a timely and cost-effective manner. It provides rapid information especially at the
project or program level. It is a quick, low-cost way to gather the views and feedback of beneficiaries
and stakeholders. In Annex 3. the results of the rapid appraisal are presented.
Highlights from the questions and remarks, and from the discussions held with the farmers are
presented below.
Famers Associations
There is a need for a farmer’s association, but it should be an association of directly involved farmers
in the area, and not a ‘distant’ organisation. In the association the famers could make agreements and
decisions concerning the management of an irrigation system, transport, marketing etc.
Willingness to Pay
If a reliable irrigation system would be installed and maintained by the government, then some
farmers are prepared to pay an affordable fee for the investment. But only when all farmers actually
pay. If irrigation water can be delivered at their plot(s) and the system is reliable, then most farmers
are prepared to pay for the water. But only if all farmers pay.
Leases
In the Project Area work both ex-Caroni workers, who have one or more leases on their name, and
farmers who have no lease themselves. One farmer had 4 leases on his name (one himself, 2 of
sons, 1 of deceased family member) and managed 20 leases of 2-acre plots from other lessees. The
farmers who have one or more leases on their name are not interested in subletting the lease,
because they are interested in farming. However, it is known that other persons who have a lease on
their name, and are no farmers, are interested in subletting. The lessees were not satisfied with the
lease conditions, because the leases are only granted for 30 years. They would like to have a lease of
99 years and preferably they would like to buy the land. Both reasons were mentioned also to
safeguard their farming business for their children/family.
32
Crops
Crops that are grown by the farmers are: hot pepper, cucumber, eggplant, cassava, eddoes, occra,
corn (limited), pumpkin, and caralli. Additional crops that the farmers would like to grow are: sweet
potatoes, tomatoes, water melon.
Attitude to Farming
The eight consulted persons were all farmers, worked all full time as farmer and like to do that. All
farmers have the opinion that they can earn a good living with farming in the Felicity Area. They are
optimistic about the future, especially if they can carry out irrigated farming. There is a fair trust that
prices for crops will be good and stable.
Integrated Pest Management (IPM)
The farmers are familiar with Integrated Pest Management (IPM) and do practise IPM. They buy as
much as possible ‘safe’ pesticides, the pesticides that are not persistent. They want to use IPM also
to market their crops and get the confidence of the consumer.
Irrigation
All famers would like to practise irrigated farming. It is most wanted in the area.
Incentives / Subsidies
Some farmers made use of government incentives (subsidies) to buy equipment and a tractor. Other
famers are not officially registered as a farmer and therefore cannot make use of the offered
incentives. This is felt as a problem.
Assistance Needed
Assistance needed to be a successful farmer: good roads and bridges/infrastructure, irrigation system water security, training (a.o. continued training in Integrated Pest Management), tractor pool. Wishes / Aspirations of Farmers
Wishes and inspirations of farmers: irrigation system, expansion of area to cultivate (there should be a first preference for ex-Caroni workers to lease/buy land that has not been distributed yet), excess roads, good bridges, tractor pool. Problems famers face:
Problems that farmers face are; lack of water, security, crops are stolen, a gate system might help. Complaints
A complaint of the farmers was: there is a lease tax of TTD 200 per year, which is not felt as high, but
not all farmers pay the tax.
Crop Insurance
None of the farmers have crop insurance. The premium is too high.
7.2 International Experiences with Water User Associations (WUAs)
In many places word wide not all people pay their water bills. The same applies for payment for
irrigation services. In general, people are willing to pay for a proper service but they would like to see
the service working efficiently before starting to pay.
33
Water User Associations (WUAs) are often formed by groups of farmers, who have shared interests in
the demand for and the management of irrigation water. WUAs can be large or small, and may be
formally constituted (as an NGO), or by informal arrangement.
Objectives of WUAs might be:
- To discuss the allocation of scarce water resources between different users (drinking water
supply, industrial, or irrigation) within a given area.
- To raise awareness of the actual water availability and the validity of claims of other water
users, in order to arrive at a just water sharing between different groups of users.
- To advise the organisation in charge of the actual distribution of water.
- To assist the member-farmers in the management of the water sources and the distribution of
available water.
Areas of responsibility:
- WUAs should not be too big, but also not too small; where possible to include a logical local
government level.
- Only to be set up where there is competition for water resources.
- In an area where people/farmers still feel a degree of community.
- Area to be selected, based on existing infrastructure and practical considerations.
Structure of organisation:
- Advisory body.
- Chaired by an elected chairman, not necessarily a government official.
- Members to be selected should represent a certain number of farmers. Irrigated agriculture
members to be elected with votes weight based on land area.
- Meeting regularly.
- Training of new members to be organised on a regular basis.
- Support from the government on technical issues when required.
In Annex 5 some international experiences on Water User Associations are presented from India,
South Africa, Egypt, and Palestine.
34
8. CHARACTERISTICS OF THE FELICITY PROJECT AREA
8.1 Introduction
In Chapter 8 relevant physical and some socio-economic characteristics of the Felicity Project Area
are presented. Subjects are described like: morphology, geology, soils, and socio-economic aspects.
Hydrogeology, meteorology, and environmental aspects are presented in separate chapters.
8.2 Morphology
The Project Area is located in central west Trinidad along a low-lying coast. The site is rather flat, has
a level of 6-8 m above sea level (a.s.l.) and is sloping gently to the coast. West of the Project Area
there are mangrove swamps, which is presently military area. These mangrove swamps are important
for the Felicity Site and other agricultural areas along the west coast, because they constitute a good
natural barrier against storms and high waters from the sea.
8.3 Geology
Geologically, Trinidad forms the eastward extension of the South American mainland of Venezuela.
Ninety nine percent of the land area consist of sedimentary and metamorphic rocks. The oldest
identifiable rocks are of Jurassic Age. Almost every stage of the Cretaceous and Tertiary Period is
present. More than three quarters of the island is occupied by strata of Tertiary Age, which contain
practically all the known petroleum reserves of the island. These strata are outcropping, or are
covered by a thin layer of Quaternary sediments. The area has been tectonically active since
Oligocene time, resulting in a complex geological framework (de Verteuil et al, 2001). The tectonic
setup of the island consists of three up thrust ranges of mountains and hills, separated by two deep
sedimentary basins.
Relevant to the Project area, located in the central western part of Trinidad, are the Central Sands.
The main aquifers in the Central Sand consist of blanket-sands, and are differentiated in:
Sum Sum Sand;
Mahaica Sand;
Durham Sand.
The Central Sands are located on the southern limb of the Caroni Syncline. They outcrop at irregular
intervals in a band extending diagonally from Claxton Bay in a north-easterly trend towards the
Cumuto area, and dip in a north-westerly direction towards the Gulf of Paria. The entire region is
heavily faulted. The faults tend to be cemented and are relatively impervious. The sands are divided
into a series of isolated pockets, which are generally not hydraulically interconnected.
8.4 Soils
The soils in the project area can be described as brown/reddish and grey clays with a salinity of 0.1-
1% and low acidity. EC-values range from 0.24-2.24 μs Sand percentage is about 45%, silt 5%, and
clay 50% (plots 67,163,194, Soil Laboratory-LWDD, Min. of Agriculture). These soils are mainly heavy
clays, that hold excessive moisture when wet and get very hard when dry. During an interview with
farmers on July 9th, it was explained that in the dry season their soils were kept wet, to avoid getting
the soils hard as concrete. Maintaining sufficient moisture retention, favourable for optimal crop
growth, is a challenge when working with these soils. The use of lime to improve soil fertility is a usual
practise in the Caroni area, but it can be costly since the soils have a tendency to keep high acidity
levels.
A major problem encountered in many irrigation projects is soil salinisation, particularly when drainage
is poor. Salinisation can be defined as a situation of nutrient imbalance (excess of salts), which
causes damage to the soil structure, like crusting and compaction, reducing the infiltration of water.
Also, salts in soil or water may reduce water availability to crops to such extent, that yields are
35
affected. To prevent soil salinisation good quality irrigation water is to be used and proper drainage is
crucial. Suitable irrigation water contributes to the nutrient balance and stabilises the soil structure.
Farming in the Felicity Project Area will generate a large volume of organic waste, which may be
utilised for the production of organic manure. This may provide abundant supply of alternative
fertilisers for the farms proposed for the Caroni (1975) Limited property. Using organic manure to
remediate soils will improve soil pH and increase fertility, while improving the structure and texture of
the soils. The latter phenomenon will help to reduce soil salinisation. It is a sustainable and
environmentally friendly practice that forms the basis for organic farming.
8.5 Socio-Economical Aspects
It is evident that at present in the Felicity Project Area there are hardly any economic activities. Only
about 10% of the land is being cultivated and thus the market of produce from the area is very small.
This situation could change dramatically if the Felicity Irrigation Project, as proposed in current report,
will be implemented. The area with its clayey soils and with sufficient irrigation water in the dry season
could produce crops during the whole year, thus increasing the farmer’s income.
For locally produced crops there is an image problem in Trinidad and Tobago. From reports in
newspapers and magazines, consumers got the opinion that agricultural produce from T&T would not
be healthy to eat. If this would change for the better, starting with the production of irrigated crops in
the Felicity Area under sustainable agriculture practices, then still a social marketing campaign would
be required to promote the awareness of the availability in T&T of new and healthy crops for an
affordable price.
Further economic aspects related to the implementation of the Felicity Irrigation Project are provided
in the chapter presenting design and feasibility.
36
9. CLIMATE AND CLIMATE CHANGE
9.1 Climate of Trinidad
The climate of Trinidad is tropical with two major seasons: a dry season from January to May and a
wet season from June to December. During this wet season a short, dryer interim period is often
recognized, called the ‘petit careme4’. The average annual temperature is 26
oC. Diurnal fluctuations
are small. The humidity is high, averaging 50 - 85 percent, especially during periods of high
precipitation. Evapo-transpiration rate is high, and average sunshine is 6-8 hours daily.
Figure 9.1: Piarco Daily High and Low Temperature
Source: TT Meteorological Services Dept. The daily average low (blue) and high (red) temperature
with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th
percentile).
Inter‐annual variability in the Southern Caribbean climate is influenced strongly the El Nino Southern
Oscillation (ENSO). El Niño episodes bring warmer and drier than average conditions between June
and August and La Niña episodes bring colder and wetter conditions at this time. Trinidad and
Tobago lie on the southern margins of the Atlantic Hurricane belt and normally escape the passage of
cyclones and hurricanes, with some notable exceptions (C. McSweeney, 2008).
9.1.1 Rainfall
Precipitation in Trinidad is influenced by the prevailing North East trade winds. Since the mountains
run at an angle with the prevailing winds, this results in a rain shadow effect where rainfall decreases
from the east coast to the west coast and increases with elevation. On average, Trinidad receives
2,200 mm of rainfall annually with 70% to 80% during the wet season, from June to December. This
means that even during the dry season occasional rainfall occurs, see Figure 9.2.
The 75-year mean annual rainfall Isohyetal map (Figure 9.3) shows that the highest rainfall intensity
occurs on the southern slopes of the Northern Range and in the north Caroni Basin with a maximum
4 Typically 14-18 days, end of September – early October (source: TT Meteorological Services Dept.)
37
depth of 3,800 mm. The west coast of Trinidad is in a rain shadow, resulting in a mean annual rainfall
of less than 1700 mm.
Figure 9.2: Rainfall distribution over the months, Couva-Tabaquite-Talparo5
Source: TT Meteorological Services Dept.
In the Felicity Project Area rainfall is between 1600 to 1800 mm per year (Figure 9.3). This means that
there is a net surplus of rainfall each year. If drainage conditions are indeed adequate this means that
the building up of salt in agricultural areas is not to be expected.
Figure 9.3: Trinidad Isohyetal Map
Source: (WASA, 2008-21).
Typically, the 1:4 year monthly rainfall (dry) is about 75% of the average rainfall (MFPLMA, 2011).
9.1.2 Evaporation and evapo-transpiration
Evaporation is usually high during the dry season, between April and June, due to high temperatures
and relatively low humidity, and it declines from July to December.
Evapo-transpiration is defined as the amount of water that is lost to the air by evaporation from water
bodies and transpiration from plants. The evapo-transpiration rate is high and varies from about 34%
5 Source of data: CRU CL 2.0 which is described in New, M., Lister, D., Hulme, M. and Makin, I., 2002: A high-
resolution data set of surface climate over global land areas. Climate Research 21:1-25 and Aquastat.
38
of the total rainfall in the wet season to about 70% in the dry season (Smith, 1965). Based on
previous reports the average annual evapo-transpiration for Trinidad ranges from 850 mm to 1000
mm6.
Figure 9.4: Relative Humidity
Source: TT Meteorological Services Dept. The average daily high (blue) and low (brown) relative humidity with
percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).
9.1.3 Wind
Over the course of the year typical wind speeds vary from 0 m/s to 7 m/s (calm to moderate breeze),
rarely exceeding 9 m/s (fresh breeze, Figure 9.5).
The highest average wind speed of 4 m/s (gentle breeze) occurs around May 5, at which time the
average daily maximum wind speed is 7 m/s (moderate breeze).
The lowest average wind speed of 2 m/s (light breeze) occurs around August 18, at which time the
average daily maximum wind speed is 5 m/s (gentle breeze).
6 State of the Water Resources, WRA, 2005
39
Figure 9.5: Wind Speed
Source: TT Meteorological Services Dept. The average daily minimum (red), maximum (green), and average
(black) wind speed with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th
percentile).
9.2 Climate Change
For Trinidad and Tobago, climate change experts believe that in the future longer, drier dry seasons,
shorter and more intense rainy seasons, and a potential increase in sea level will occur. Because of
expected higher frequency and intensity of tropical storms, more flooding in low lying areas is
expected.
In brief, the Caribbean region global climate change (GCC) is expected to result in (CCCC, 2009):
a more hostile regional climate;
rise of temperature of about 0.2 °C per decade;
higher frequency and intensity of tropical storms and hurricanes;
more severe droughts;
rising of sea level. There are several scenarios that predict the climate change for the Caribbean area and Trinidad and
Tobago.
9.2.1 Change in temperature
Temperature observations
Mean annual temperature in Trinidad and Tobago has increased by around 0.6°C since 1960, an
average rate of 0.13°C per decade (period of 48 years). There are insufficient daily data to identify
trends in daily temperature extremes (C. McSweeney, 2008).
According to Vanessa Hyacinth-Ash (Piarco, 2011), the temperature showed an increase of 2.5°C
over a forty year period (period 1971-2010). This means a temperature rise of 0.63°C per decade.
Concerning observations, there is not a good resemblance in temperature rise per decade among
both sources. However, the periods were partly different, resp. 1960-2008 and 1971-2010. The latest
40
period, 1971-2010 (Vanessa Hyacinth-Ash, 2011) shows the highest rise of mean annual temperature,
namely 0.63°C per decade (2.5°C o v e r a p e r i o d o f f o r t y y e a r s ) .
Temperature projections
Temperature data for Piarco, in the period 1971-2010, suggest average annual temperature rises of
maximum and minimum temperatures of 0.04894°C and 0.04551°C, which would be per decade
respectively 0.49 and 0.46°C (Jones, 2013). The rise of temperature in the region will be about 0.2°C
per decade, according to CGC (Caribbean Global Climate Change).
C. McSweeney (2008) provides a projection for the mean annual temperature for Trinidad and
Tobago. The range of projections by the 2090s, under any one emissions scenario, is around 1‐2°C.
Consequently, a temperature rise of 0.12°C – 0.24°C per decade is expected over a period of 82
years (2008-2090).The projected rate of warming is similar throughout the year.
The range of 0.12°C – 0.24°C per decade, as mean annual temperature rise, is quite large. To select
a figure – as the rise of mean annual temperature till 2050 – for the various scenarios for irrigation
development, the higher figure of 0.24°C has been selected. The reason is, that Hyacinth-Ash (2011)
comes with a evidently higher observation of temperature rise per decade than McSweeney. The
figure of temperature rise of 0.24°C per decade is quite close to the figure of 0.20°C per decade from
CGC.
9.2.2 Change in precipitation
Precipitation observations
There has been a small decline in rainfall and in number of rainy days over a forty years period.
Mean rainfall has decreased fractionally since 1960, but it is not a statistically significant trend. The
largest changes are in the wet season, where, on average, rainfall has decreased by 6.1 mm per
month (2.6%) per decade. For drainage analysis extreme daily rainfall data are required, however,
there are insufficient daily data to identify trends in daily rainfall extremes (C. McSweeney, 2008).
Precipitation projections
Projections of mean annual rainfall from different models are broadly consistent in indicating
decreases in rainfall for Trinidad and Tobago. Annual projections vary between ‐61% and +23% by
the 2090s, with median values of ‐13 to ‐21%. The proportion of total rainfall during heavy showers
decreases in most model projections, changing by ‐20% to +7% (2090s). Maximum 5‐day rainfalls
tend to decrease in model projections, changing by ‐29 to +20mm by (2090s, C. McSweeney, 2008).
Model simulations show wide disagreements in projected changes in the amplitude of future El Niño
events, contributing to uncertainty in future climate variability in projections for the region.
9.2.3 Sea level rise
The Caribbean islands are vulnerable to sea‐level rise. Sea‐level in the region is projected by climate
models to rise by the following levels by the 2090s (relative to 1980‐1999 sea‐level):
0.13 - 0.43 m (SRES B1);
0.16 - 0.53 m (SRES A1B);
0.18 – 0.56 m (SRES A2).
9.2.4 Impacts and mitigation measures
Major climate change phenomena which are relevant for T&T are: rise of temperature, more intense
rainfall, higher frequency and intensity of tropical storms and hurricanes, more severe droughts, and
rising sea levels. These climate change occurrences will have a certain impact. Relevant to
agriculture these impacts may be: lower crop production, more severe floods, higher frequency of
floods, soil erosion, coastal erosion, and salt water intrusion. These impacts of climate change
occurrences can be mitigated to a certain extent by mitigation measures. Several mitigation measures
41
which are relevant to agriculture, together with the most prominent climate change occurrences and
their impacts, are summarised in Table 9.1.
Table 9.1: Climate change, impacts and mitigation measures
Climate Change Impacts of climate Change Mitigation Measures
Rise of temperature More intense rainfall, higher frequency and intensity of tropical storms and hurricanes More severe droughts Rising sea levels
Lower crop production Higher frequency of floods; more severe floods Soil erosion, hardening of soils Coastal erosion, salt water intrusion, flooding
Development of crops that can grow under higher temperatures, proper water management Good drainage systems, proper water basin management, reforestation, soil conservation Soil conservation, planting trees, wind breakers, crop rotation, mulching, proper water management Protection of coasts by wetlands, mangrove forests, dikes, producing salt tolerant crops
42
10. HYDROGEOLOGY
10.1 Introduction
In Chapter 10 the hydrogeological aspects of the Felicity Project Area are presented. In Chapter 10
’Irrigation Water Requirements’, the hydrological characteristics of the area are provided, linked with
the subject of irrigation options for the Project Area.
Before 1981 60% of the total municipal water supply was provided by groundwater. After large
surface water plants were constructed, such as the Caroni-Arena Pump Storage Complex and the
North Oropuche Scheme, groundwater has accounted only for about 25% of the total water supply of
Trinidad. Few parameters are known of the aquifers in Trinidad and Tobago. Original pumping test
data of the tests performed were lost during a fire in the WRA office 1973.
Sufficient and accurate aquifer parameters are required to develop a groundwater model for an
aquifer and to obtain reliable output. No groundwater modelling has been applied for the aquifers of
Trinidad and Tobago so far. Methods used to estimate groundwater potentials for Trinidad and
Tobago are:
water balances (water storage/balance equation)
Maximum Sustained Yield (MSY) method.
10.2 Aquifers in Central Trinidad
In Central Trinidad the major aquifers are the Central Sand aquifers, consisting of blanket-sands.
They are differentiated in:
Sum Sum Sand;
Mahaica Sand;
Durham Sand. The Central Sands are located on the southern limb of the Caroni Syncline. They outcrop at irregular
intervals in a band extending diagonally from Claxton Bay in a north-easterly trend towards the
Cumuto area, and dip in a north-westerly direction towards the Gulf of Paria. The entire region is
heavily faulted. The faults tend to be cemented and are relatively impervious. The sands are divided
into a series of isolated pockets, which are generally not hydraulically interconnected. The division
between the Sum Sum and the Mahaica Sands is marked by a large structural shift.
General aquifer characteristics of the Central Sands (Talparo Formation) are:
aquifers consisting of fine to very fine marine sands;
the Sum Sum/Mahaica Sands and Durham Sands are separated by the Caparo clay Member of the Talaro Formation (300 m thick);
Age of Formation: Pleistocene;
aquifers are confined. The major source of recharge is direct infiltration by rainfall into the pervious valley soils, and
streambed infiltration.
10.3 Potential of Groundwater in the Project Area
The project area is situated in the western part of ‘The Central Sands'. The major source of recharge
is direct infiltration by rainfall into the pervious valley soils, and streambed infiltration.
Annex 6 presents the characteristics of the aquifers and the well fields in the region of the Project
Area. Nearest well field is the Carlsen Field Wellfield in the Sum Sum Sands, south-east and
approximately 3 kms from the Project Area. The lithology for the Sum Sum Sands is: fine to very fine
sand, some silts and clays. The average Specific Capacity is 163 m3/day/m, Transmissivity (T) is 225
m2/day, and hydraulic conductivity (K) is 5 m/day, indicating that this aquifer has a rather low
43
permeability. The data on lithology coincides with data from wells near the Project Area. The Carlsen
Field Wellfield is over pumped and water levels are declining.
There are only a few data available on hydrogeology and groundwater related to the Project Area. On
the Hydrogeological Map of Trinidad (plate 255) is indicated that the area has a ‘marginal well yield
production potential of 20-100 igpm’, which is equal to a yield of 5.5-27.3 m3/hr. From the few
boreholes near the Project Area, only 2 logs provide data on pumping tests. The nearest by borehole
SDH478, just north of the Project Area, is not a production well and there are no pumping test data
available. The description of the lithology at that particular site would be worthwhile, however so far
the log could not be traced, Two boreholes, borehole 1635Cg (north-east, approx. 2.5 km from the
centre of the Project Area) and borehole 1637Cf (Carlsen Field Wellfield, approx. 2 kms from the
centre of the Project Area) provide pumping test data. The pumping tests were carried out for 6-8
hours with airlifting.
Borehole 1635Cg, the most representative production borehole for the Project Area (depth 45.8 m),
was drilled in a sequence of clay and sand. The static water level was 2.10 m b.g.l. and the pumping
level was 7.93 m b.g.l. Discharge was 8.19 m3/hr. The Specific Capacity is: Q/s = 33.6 m
3/day/m. The
lithology for borehole 1637Cf in Carlsen Field Wellfield (depth 33.6 m) is described as ‘reddish yellow
sand’. The static water level was 2.44 m b.g.l and the pumping water level 6.1 m b.g.l. Discharge was
3.54 m3/hr. The calculated Specific Capacity, Q/s = 23.3 m
3/day/m. The low figures of the Specific
Capacities for the 2 boreholes, resp. 33.6 m3/day/m and 23.3 m
3/day/m and the low discharges of the
2 boreholes of 3.54 m3/hr and 8.19 m
3/hr coincide quite well with the potential yield of 5.5-27.3 m
3/hr,
as indicated on the Hydrogeological Map of Trinidad (plate 255).
Another phenomenon, straight from farming practise in the Project Area – and brought forward during
the rapid appraisal (chapter 7) – is that once existing irrigation ponds are pumped empty, they are not
filling up from groundwater. It confirms the low permeability of the clayey soils in the Project Area,
since the irrigation ponds (depth 4.5 m) have been dug into the groundwater.
Conclusion
Realising that the Carlsen Field Wellfield (used for drinking water) just south-east from the Project
Area is over pumped and water levels are declining, and the permeability is generally low in the
Central Sands, the conclusion is that groundwater as a source for irrigation water should not be a first
option. Another reason is that salt water intrusion could be generated, which would be detrimental for
the quality of the groundwater in the Project Area, but could also be a risk for the drinking water
production in Carlsen Field Wellfield. Moreover, test results of a nearby borehole indicated a water
quality that was not adequate for irrigation (chapter 11.1).
Consequently, the potential for groundwater abstraction in the Project Area, in the shallow aquifers, is
low. There are no data on deep boreholes or deep aquifers in the project area, but these would not be
relevant, because abstraction of deep groundwater is expensive and not advised, because of a
serious risk of salt water intrusion. Pumping limited amounts of groundwater for irrigation, as an
additional or back up source for irrigation water might be a possibility, but in that case a proper
hydrogeological investigation should be carried out in the area to identify the fresh-saltwater interface
and the maximum yields that boreholes could be pumped.
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11. WATER QUALITY
11.1 Ground Water Quality
Parameters related to agriculture and specifically to irrigation are: pH, TDS, Electrical Conductivity,
Chloride, Ammonium, Phosphate, Sulphate, and the parameters Calcium, Magnesium and Sodium.
Especially levels of Nitrate, Ammonium, Phosphate, Potassium and Sulphate will give an indication
about the effect of fertilizer use on the quality of ground water.
Generally, water from the Sum Sum, Mahaica and Durham Well Fields have a high iron content (Las
Lomas, 11 mg/l) (Water Resources Strategy, 1999). Existing ground water quality data could be
obtained from two production boreholes near the project area, borehole 1635Cg north-east
(approx.2.5 km) of the Project Area, and borehole 1637Cf in Carlsen Field Wellfield south-east
(approx.2km) of the Project Area. The test results of the most representative sample (borehole
1635Cg) is presented in Table 11.1. No existing groundwater quality data are available on pesticides.
Table 11.1: Groundwater quality near the Project Area
Sample
parameter
description units/parameters results
WHO
standard
taken: 26-Jul-2010 Colour Hazen Units 19 < 15
ref: 420/22/00/1007ALES Turbidity N.T.U 5 < 5
Sample location: Aleson Readymix Ltd (well #1) pH
6.2 6.5 - 8.5
Electrical Conductivity μmho/cm 5850
Total Hardness CaCO3 mg/l 2000
Calcium Ca
2+ mg/l 447
Magnesium Mg
2+ mg/l 212
Chloride Cl
- mg/l 1005 < 250
Total Iron Fe
3+ mg/l 20 < 0.3
Source: WRA,#1940Cg/1635Cg
Generally, for irrigation water the following advisory levels for Electrical Conductivity are defined:
< 1,000 μmho/cm: unrestricted use;
1,000 - 2,000 μmho/cm: restrictions on several types of vegetables.
A guideline value of approximately 1,500 μmho/cm is generally used for potable water.
It is evident that the pumped water from borehole 1635Cg would not be suitable for drinking water, but
even for irrigation water – with its high EC-value – the quality is not adequate. The sample was not
compliant with WHO guidelines for potable water for Total Iron, Colour and Chloride and the Total
Coliform count was 500, indicating that the water was bacteriologically unsafe. As expected, the test
results of water from borehole 1637Cf in Carlsen Field Wellfield indicated that the quality of the water
was adequate for potable water (μmho/cm 800; Cl- 100 mg/l, Total Coliform count 3) and thus also for
irrigation water. Electrical Conductivity of tested water from borehole 1635Cg was 5,850 μmho/cm,
which indicates that the water is unsuitable for most vegetables.
An indication of salt water intrusion in groundwater in the Project Area could not be obtained, because
there are no boreholes in the project area itself of which data could be attained. However, the water in
borehole 1635Cg, north-east of the Project Area, has a rather high salt content (EC 5,850 μmho/cm),
which might indicate saltwater intrusion in groundwater. A proper hydrogeological study should reveal
whether the area suffers of saltwater intrusion.
45
11.2 Surface Water Quality and Salt Water Intrusion
Incoming brackish water from the coastal zone – influenced by the tides with a range of 1.5-2m – west
of the Project Area and carried along in the Caparo River and Chandernagore River, may affect the
quality of surface water and groundwater. To investigate this possible phenomenon, available surface
water quality data from the Caparo River were examined (Annex 7). The time on which the
measurements were taken have not been recorded, so it is not possible to search for a correlation
with tidal fluctuations. The bulk of data is available from October 2005 till September 2008. The
sample location was east of the Felicity Project Area (Todd’s Bridge). No analyses on Chloride
content had been carried out, but amongst other parameters on Total Dissolved Solids (TDS) and
Electrical Conductivity. Two measurements were carried out during dry season (March 1991 and April
2009) and 15 measurements during the wet season (October, November, 2005, 2007, 2008).
Generally, water with TDS-values of 0-1,000 mg/l is regarded as fresh and water with values of 1,000-
10,000 mg/l as brackish. TDS values ranged from 362-533 mg/l, and even the 2 figures from the dry
seasons reached no higher than values of resp. 215 and 320 mg/l. The available lab tests indicate that
the Caparao River water at the sample point was fresh; no indication of salt water intrusion.
Electrical conductivity ranged from 124 to 673 μmho/cm during the wet season and the measurement
on 20-3-1991 gave a value of 470 μmho/cm. The average value during the wet season was 513
μmho/cm. The average for 2005 was 265 μmho/cm (3 measurements), for 2007 563 μmho/cm (12
measurements) and for September 2008 (1 measurement) the value was 410 μmho/cm. From 2005
till 2008 an up-going trend can be seen in Electrical Conductivity.
Generally, for irrigation water the following advisory levels for Electrical Conductivity are set:
< 1,000 μmho/cm: unrestricted use
1,000 - 2,000 μmho/cm: restrictions on several types of vegetables The conclusion can be drawn that the analysed water from the Caparo River would be suitable for
irrigation and would have no restrictions. At the same time the results indicate no saltwater intrusion
from sea in the tested water from the Caparo River at the sample location east of the Project Area.
11.3 Test Results on Water from the Felicity Project Area
To obtain knowledge on water quality in the Project Area 3 water samples were taken from existing
irrigation ponds (nos: 19, 116, and 240; map ‘Felicity Irrigation Ponds, Phases 1 & 2) and 2 water
samples from incoming waters from the Caparo River and the Chandernagore River. The complete
test results of the water samples from the Project Area are presented in Annex 8. Guidelines for the
interpretation of water quality for irrigation is shown in Annex 9 (FAO, 1904).
11.3.1 Pesticides
In the water samples none of the 50 analysed persistent and non-persistent could be detected. No
pesticides were found in the water from the Caparo River and the Chandernagore River and none in
the water samples that were taken in three irrigation ponds in the Project Area.
11.3.2 General chemical/physical parameters
Five samples were analysed on the following chemical/physical parameters: pH, TDS, Electrical
Conductivity, Chloride, Sodium, Calcium, Magnesium, Ammonia, Phosphate, Sulphate, and on a
range of 50 Pesticides. The test results of water samples on the chemical/physical parameters are
presented in Table 11.2.
46
Table 11.2: Test results of water samples from the Project Area Sample Values
Sample number A1639/13 A1640/13
A1641/13 A1642/13 A1643/13
Parameters Analysed
Caparo River North of Plot 275
Pond on Plot 240 Felicity #2
Chandernagore River
Pond on Plot 116 Felicity 1
Pond on Plot 19 Felicity 2
pH 7.24 6.77 6.44 8.29 7.97
Electrical Conductivity, μS/cm (μmho/cm)
280.00 1072.00 52.40 5890.00 257.00
Total Dissolved Solids, mg/l
735.00 651.50 227.00 4292.50 257.00
Ammoniacal Nitrogen (as NH3-N) mg/l
2.34 0.78 1.38 0.55 0.74
Total Phosphates, mg/l
1.38 0.08 3.73 < 0.05 1.62
Chlorides, mg/l 31.55 0.88 me/l
183.56 5.18 me/l
46.41 1.3 me/l 692.79 19.54
me/l
17.45 0.49
me/l
Sulphates, mg/l 0.12 0.73 0.15 4.82 0.12
Calcium, mg/l 47.34 1.31 me/l
38.13 1.90 me/l
46.04 2.30 me/l
57.80 2.88
me/l
29.95 1.49
me/l
Magnesium, mg/l 11.02 0.91 me/l
25.43 2.09 me/l
10.26 0.84 me/l
211.34 17.38
me/l
10.08 0.83
me/l
Sodium, mg/l 26.19 1.14 me/l
115.14 5.01 me/l
28.63 1.25 me/l
759.27 33.02
me/l
45.09 1.96
me/l
11.3.3 Sodium Adsorption Ratio (SAR) Values
SAR-values were computed to obtain an indication of the suitability of the water in the Project Area for
irrigation purposes. High SAR-values reflect a high concentration of dissolved solids and indicate a
tendency of water to replace adsorbed calcium and magnesium with sodium, which damages soil
structure. The computed SAR-values are presented in Table 11.3.
The water classification for irrigation, based on SAR-values is:
Na SAR = ---------------- milli-equivalents per litre (me/l) (Ca + Mg)/2 < 10 excellent 10-18 good 18-26 fair >26 poor
47
TABLE 11.3: SAR-VALUES OF WATER SAMPLES TAKEN IN THE PROJECT AREA
Caparo River North of Plot 275
Pond on Plot 240 Felicity #2
Chandernagore River
Pond on Plot 116 Felicity 1
Pond on Plot 19 Felicity 2
Sodium me/l
1.14 5.01 1.25 33.02 1.96
Calcium me/l
1.31 1.90 2.30 2.88 1.49
Magnesium me/l
0.91 2.09 0.84 17.38 0.83
SAR-value 1.0 2.5 0.8 3.3 1.7
11.3.4 Conclusions
Using the guidelines for the interpretation of water quality for irrigation (Annex 9, FAO, 1904), together
with computed SAR-values, and generally accepted values for TDS and Electrical Conductivity,
conclusions could be drawn for the analysed samples.
Table 11.4 presents a matrix of water quality aspects for the water samples taken in the Project Area.
None of the water samples showed detectable concentrations of pesticides (detection limit 0.02 μg/l).
The water from the Chandernagore River has the best quality, followed by the pond on plot 19. The
water from the Caparo River follows next. The irrigation pond on plot 240 has a mediocre water
quality for irrigation and the water quality in the pond on plot 116 scores negative for values of
Electrical Conductivity, Total Dissolved Solids, and Chlorides. Computing SAR-values, taking into
account the concentrations of Sodium (Na+), Calcium (Ca2+
) and Magnesium (Mg2+
), the values for all
samples appear to be good. It is not easy to indicate why the water from the pond on plot 116 has
evidently the lowest quality. Possibly the pond has not been refreshed by pumped irrigation water and
has been under evaporation for a long time, while the other ponds might have been refreshed. All the
ponds can be used to store irrigation water, because they are going to be filled and discharged on a
regular basis. In the future more, regularly, and also in the dry season, water quality tests should be
carried out in the Felicity Project Area; certainly when this irrigated agricultural land serves as a Pilot
Area.
Total Dissolved solids (TDS)
Fresh water: TDS-values of 0-1,000 mg/l
Brackish water : TDS-values 1,000-10,000 mg/l
Electrical Conductivity (EC)
Advisory levels for irrigation water:
< 700 μmho/cm: unrestricted use 700 – 3000 μmho/cm: slight to moderate restriction on use > 3000 μmho/cm: severe restriction on use
48
TABLE 11.4: WATER QUALITY MATRIX RELATED TO IRRIGATION FOR SAMPLES TAKEN IN
THE PROJECT AREA
, Caparo River North of Plot 275
Pond on Plot 240 Felicity #2
Chandernagore River
Pond on Plot 116 Felicity 1
Pond on Plot 19 Felicity 2
pH + + + + +
Electrical
Conductivity
+ _ + _ _ +
TDS _ _ + _ _ +
Chloride + _ + _ _ +
Sodium + _ + _ _ +
Ammonia + + + + +
Phosphate + + + + +
Sulphate + + + + +
SAR-value + + + + +
Pesticides + + + + +
49
12. ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES
12.1 Introduction
Environmental management in Trinidad and Tobago is controlled by the National Environmental
Policy (NEP), developed and updated under the National Environmental Management Act of 2000.
The Act provides a rational and comprehensive framework for environmental management and
ensures that the natural resources of the country are used for social and economic development,
while protecting human health and supporting sustainable development.
Due to irrigation practises several components of the physical and human environment may be
affected, whether this is negative or positive. A strong positive impact is expected from the
introduction of irrigation on the socio-economic situation. Potential negative environmental impacts of
irrigation systems may be caused by agricultural runoff on surrounding rivers and downstream users,
affecting water, soil, flora and fauna (biodiversity), landscape, and human health (pesticides
&fertilisers, re-use of waste water).
Also from outside there are effects on cultivated land, of which the major impact is climate change.
These aspects are presented and clarified in next chapters. Environmental impacts that are found to
originate from the proposed source for the irrigation scheme are further elaborated on in the chapter
on design of the system. First a brief overview is provided of the Strategic Environmental Assessment
(SEA) of the Implementation of the National Sugar Adaptation Strategy, that was prepared in 2009
(Niras).
12.2 Positive Impact on the Socio-Economic Situation
Turning the former sugar lands of Caroni (1975) Ltd. in cultivated and irrigated farm lands, will have a
positive influence on the regional socio-economic situation. The arrangement to use the property for
agriculture shall generate positive economic returns, resulting in increased rural income and creation
of employment. When the irrigated farm lands prove to be profitable, than workers will be attracted to
these areas. These farmers will then produce and supply a wide range of fresh agricultural products,
which will most likely adjust prices downward. Consumers will benefit from healthier agricultural
products at lower prices. Also the issue of food security will be enhanced.
12.3 Strategic Environmental Assessment and Environmental Sustainability Plan
The objective of the EC supported Strategic Environmental Assessment (SEA) of the National
Adaptation Strategy (NAS) was to examine the environmental, social and economic impacts of
planned activities on the development of the former Caroni Ltd. properties. The SEA addresses
herewith the agricultural diversification from cane production to alternate agricultural uses. The SEA
focuses on the planned use of 76,000 acres, formerly used for cane production. The SEA brought its
recommendations within the existing planning, policy and objectives of the Government of Trinidad
and Tobago (GoRTT), specifically the country-wide strategic initiative Vision 2020. The importance of
the SEA for the Felicity Irrigation Project is the series of plans for Caroni (1975) Ltd. currently under
development. These include development of agricultural activities on 13 mega farms, but also on
14,000 acres of ‘2 acre plot’ leases.
An Environmental Sustainability Plan was development and implemented in 2012 by the GORTT for
lands formerly owned by Caroni (1975) Ltd., which were earmarked for agricultural, residential and
industrial development. The objective of the Environmental Sustainability Plan was the development
of these lands in an environmentally sustainable manner by all stakeholders, ensuring that the needs
of the present are met without compromising the welfare of future generations. It is from this detailed
examination of the planned alternatives for the Caroni lands, that mitigation and enhancement
measures were generated The following were the recommendations:
50
Recommendations for agricultural development:
Conduct biodiversity surveys of all Caroni Ltd. properties for future baseline references.
Formation of farmer's cooperatives with development of management rules.
Soil remediation and water management schemes implemented in all mega farms and on all
2-acre plots, with at least 40% under organic cultivation.
Development of a joint sustainable agri-business degree program at the University of West
Indies (UWI) and the University of Trinidad and Tobago (UTT).
Increase domestic food production and consumption rate with local branding, with minimal
agro chemical usage.
Implementation of a Social Marketing campaign for local produce.
12.4 Impacts on Water and from Water
Irrigation may have a variety of impacts on water. If irrigation water with a load of fertilisers and
pesticides is discharged on surface water, it may have a negative impact on these waters (disturbing
aquatic systems), but also on areas reached by these surface waters. For example in the greater
Project Area the mangroves west of it, might in such a case be negatively affected. Enclosed
systems, because of limited contact with the surroundings, generally have minor impacts on the
natural environment. Small reservoirs can improve the availability of irrigation water, however they
may also - depending on the subsoil and the quality of the irrigation water - cause contamination of
groundwater. In addition, small reservoirs are liable to deteriorate the quality and the nutrient balance
in irrigation water as a result of warming and eutrophication. It all depends on the actual situation
(Niras 2009, MoP, 1999-6). At present the Caparo River is already heavily polluted by domestic waste
waters, farm chemicals and industrial effluents. In case the preferred options for irrigation are
implemented in the Felicity Project Area, then more water of better quality will be transported to the
Project Area and the environmental situation concerning impacts from incoming waters will improve.
Reservoirs, open water conveyance and distribution systems for irrigation will lead to water losses by
evaporation and will have a slight influence on the microclimate. Because the best option for the water
source for irrigation water in the Project Area is surface water from the Caparo River, the protection of
the Caparo River watershed is important. Closed loop systems, if included in the design of the
irrigation works, will reduce the required amount of ‘fresh’ irrigation water.
Water quality aspects and test results of water samples taken in the Felicity Project Area are
presented in chapter 11.
12.5 Impacts on Soil
Impacts on soils vary in nature, however related to irrigation development there is a specific set of
potential impacts that can be identified. Table 12-1 presents the potential impacts from irrigation
activities on soils and their mitigation measures.
Table 12.1: Potential impacts on soils from irrigation activities, mitigation measures
Potential Impacts Mitigation Measures
Erosion of embankments of channels and reservoirs Sedimentation of channels Damage of soil structure, soil erosion by water and wind Damage to soil fertility and over fertilisation, pollution
Stabilising embankments, ground covering plants with dense root systems Flushing of channels, cleaning Soil conservation, crop rotation, mixed cropping, mulching, improvement of soil structure and nutrition by organic manure and compost Balanced use of fertilisers, Integrated Pest Management
51
Salinisation Impact of construction activities, spilling of materials (cement, oil), compaction Production of organic waste
Proper drainage Proper environmental management and monitoring Proper waste disposal and composting
12.6 Impacts on Flora and Fauna (biodiversity)
When irrigation is introduced, certain species of flora and fauna may disappear, while its management
may favour other species. A reduction in dry biotopes is set against the replacement by aquatic
biotopes. Increases and decreases in the presence of particular species may have both positive and
negative consequences for man and nature, but because most of the area was, and will be, under
cultivation the impact is negligible. It must be realised that the Project Area is not a nature reserve
and has been under extensive cultivation for sugar cane already for a long time. It is even felt that
prolonged cultivation of the a mono-crop sugarcane – combined with spraying of (at that time)
persistent pesticides – has resulted in extensive loss of biodiversity within the area. There are reports
of the re-appearance of some animals and plant species into the area since the closure of the sugar
lands. The renewed agricultural activities developed on the 2-acre plots should have a positive impact
on biodiversity, if a sustainable approach is maintained.
12.7 Impacts on Landscape
The nature of the landscape in the Project Area will not change significantly and ‘nature’ as such has
never been a characteristic of the Felicity area. It was and is an area under extensive cultivation with
all characteristics of that, like a quite monotone cultivated landscape with little space for trees or wild
plants.
12.8 Impacts on Human health
Irrigation schemes may create health risks. The main health risk is caused by the use of pesticides
and to a lesser degree by overdoses of fertilisers, re-use of irrigation water and use of untreated
waste water, and water borne diseases.
12.8.1 Pesticides and fertilisers
Although irrigated agriculture is not necessarily a type of cultivation that gives higher risks than other
types of farming, the risk of the use of pesticides must be taken into account. Pesticides may have
toxicological, and carcinogenic properties, as well as effects on, and risks for, the balance of nature.
Active ingredients are accordingly assigned to toxicity classes. The FAO Code of Conduct, adopted in
1985, contains recommendations on the registration, distribution and use of pesticides. Numerous
pesticides involving comparatively high risks have been taken off the market and restrictions are
imposed on their use.
Organo-chlorine Pesticides
Heptachlor and Lindane are both broad-spectrum organo-chlorine insecticides. Lindane
slowly degrades by soil micro-organisms.
Heptachlor persists for prolonged periods in the environment. It is converted to the more toxic
heptachlorepoxide in the soil, in plants and in mammals. Heptachlorepoxide undergoes bio-
concentration in many species and accumulates in the food chain. Generally, since 1975 the
use and the production volume of heptachlor have declined, because of a registration
suspension notice by the EPA (1976) for all food crop and home use. However, use of
52
heptachlor for termite control and non-field crops continues.
DDT and its derivatives are persistent organo-chlorine insecticides. They are stable under
most environmental conditions and are resistant to complete breakdown. In their different
isomeric forms they are rather insoluble in water, but soluble in organic solvents. Its use has
been restricted or prohibited for ecological reasons in many countries, also because of the
increasing resistance of pests to this type of pesticides. DDT is still used in the public health
sector in several tropical countries.
In particular, use of persistent, broad-spectrum agents is internationally banned. Preference should be
given to pesticides with low toxicity, a selective action and low persistence. The ‘dirty dozen’ comprise
the following fifteen active ingredients which should be proscribed in view of the substantial risks
attached to them:
Insecticides: Chlorinated hydrocarbons: aldrin, chlordane, DDT, dieldrin, endrin, HCH-mixed
isomers, heptachlor, lindane, camphechlor; Carbamates: aldicarb (proprietary name: Temik);
Organophosphates: parathion (E 605); Other insecticides: dibromochloropropane (DBCP),
chlordimeform, penta-chlorophenol (PCP).
Herbicides: 2,4,5-T (proprietary name: Weedone)
Another risk of the use of pesticides is the unsound disposal of leftovers and empty packaging
materials. Pesticides should be used within the framework of integrated plant protection methods
(IPM).
Mitigation measures Mitigation measures related to the use of pesticides and fertilisers are:
Use biodegradable substances to control pests and diseases.
Employ cropping systems that encourage low fertilizer usage.
Use natural fertilizers to complement the use of organic manure.
Provide practical alternatives to the use of chemicals.
Adapt integrated farming systems that are designed to control pests and diseases.
Ensure that biological control methods are available, accessible and affordable to farmers.
Train farmers in Integrated Pest Management.
Provide training on water management, quality and conservation awareness.
Use biological control measures and Integrated Pest Management practices.
Reinforce the use of proper protective gear.
Encourage farmers to form cooperatives to obtain easier access to training and support.
12.8.2 Re-use of irrigation water and use of untreated wastewater
The use of wastewater in irrigation water poses risks to both farmers and consumers. However, if a number of rules and guidelines are followed, even untreated wastewater can be used to produce horticulture crops. In general irrigation water is a mix of treated wastewater and surface water, which may in itself be polluted with sewage. For a successful application of irrigation water, which includes a proportion of wastewater, the
following topics need to be addressed:
Often is stated that (treated) wastewater may not be applied in agriculture, however in
practice irrigation water is commonly polluted with sewage in various degrees. A good
approach would be to prepare guidelines which clearly indicate, for each quality class of
irrigation water, which crops can be irrigated and which precautionary measures field workers
need to take. Both to protect themselves and to prevent contamination of crops.
53
There needs to be agreement on the level of treatment of wastewaters before discharging it
into surface water or directly into an irrigation conveyance system. This is similar to existing
guidelines on wastewater discharge and surface water pollution (Ministry of the Environment).
It is important that consumers have faith in the authorities and in their competence to enforce
standards, ensuring healthy, uncontaminated food. In practice this may be a problem in
Trinidad, as illustrated by the public conviction that food crops contain excessive and harmful
levels of agro-chemicals.
12.8.3 Waterborne diseases
Waterborne diseases, particularly schistosomiasis and onchocercosis, may occur as a health risk in
irrigation systems by stagnant water. Depending on how it is transmitted (via human excretion),
schistosomiasis may well occur in areas being irrigated for the first time. Irrigated farming can also
promote the spread of hookworms and eelworms. Malaria, which often spreads in areas where large
irrigation schemes are being realised, can constitute a problem in small-scale projects using open
reservoirs and water conveyance systems. Because irrigation has so far not widely been introduced in
Trinidad and Tobago, waterborne diseases related to this type of agriculture is not common. It is
advised to monitor a possible spreading of waterborne diseases in areas where irrigation is being
introduced.
54
13. IRRIGATION SECTOR STUDY
Given the current status of irrigated agriculture in the country where the present irrigated area is small
(approx 5,000 ha7) and the corresponding water allocation to the sector also small (less than 5 % of
the Public Water Supply) the result is that agriculture in Trinidad and Tobago is practised essentially
under rain fed conditions. The implications of a rain fed system of agriculture is that the sector will
continue to be under-developed with the majority of arable land fallow during the first 6 months of the
year and tree crop production at a subsistence level. Provision of sustainable irrigation and drainage
projects would allow for maximum use of the land (reference: ToR).
Generally, the introduction of irrigation provides more reliable yields and incomes, though it also
entails a significant investment and needs ongoing operation and maintenance (O&M). While the
O&M costs are usually translated into fees to be paid by the beneficiaries, e.g. the farmers, the initial
investment is often paid for by the government or by a multi-lateral financing agency. Surprisingly this
is also often the case in developed and rich countries such as the USA or France.
Irrigation generally covers the following components:
- provision of a water supply through storage in reservoirs, use of river water and/or tapping of
groundwater;
- conveyance and distribution of irrigation water by open channels or pipelines;
- field application systems of irrigation water by means of sprinkling, drip irrigation flooding, basins,
border strips, and rills;
- drainage by means of open or concealed systems.
Irrigation is typically thought of as being applied in arid or semi-arid areas, but most of the worlds’
irrigation takes place in areas that have relatively large amounts of rainfall, only the rainfall is
unevenly distributed in place and/or time. This is the case in Trinidad, where irrigation is primarily
applied during the dry season, typically the months from January through May/June. An interesting
conclusion of the calculation of crop water requirements is that even during the rainy season a clear
need for irrigation water exists, which will become more pronounced due to effects of climate change
(see calculations later in this chapter).
In this Chapter an overview of available information and knowledge is presented, providing an
understanding of the irrigation sector for the former sugar growing areas, located on the low areas in
the west of Trinidad. Within the scope of this study, which is limited in time and manpower, the scope
of this overview is necessarily linked to the available time and available data, as it was not possible to
plan more than very limited number of site visits and even the collection of relevant documents and
reports.
13.1 Water resources in the former sugar growing areas
This assessment is done as a desk study and is based on the information made available to the team.
The conclusion based on this information is that not very much can be added to the conclusions
drawn in the (MOP-1999-6) study and the (WASA, 2004-21) Water and Wastewater Master Plan and
Policy. If irrigated agriculture is to be expanded at the rate that was planned in 1999 (e.g. to more
than 100,000 ha for Trinidad) the available surface water resources will not be sufficient to meet the
full potential irrigation requirements. For specific potential irrigation areas the type of crops and
especially the water requirements of these crops need to be matched with available irrigation water
resources, taking into account competing water requirements for domestic water supply and possibly
industry.
7 In other publications areas as small as 3,000 ha are mentioned (MOP-1999-6 and WASA 2004-21)
55
The calculation for the irrigation water requirements for the Felicity pilot area will show that the
provision of optimal irrigation water supply is only possible for limited parts of the former sugar lands
and has to be linked to specific sources8. Use of individual ponds on the land of the farmers is an
option that does not rely entirely on the availability of surface water in the rivers, but the amount of
water that can be stored without an undue claim on arable area is not sufficient to bridge the entire
dry season. This was rather strongly stated during stakeholder meetings with farmers of the Felicity
Pilot Area (Chapter 7). However, the ponds are an important storage reservoir, if built and used
correctly.
One main source of surface water for both water supply and irrigation in the former sugar growing
areas is the Caroni River. The hydrology of this river has been extensively studied and is again being
studied by the ongoing Caroni River Basin Drainage Study (Royal HaskoningDHV, Deltares, for
NIDCO). Another very relevant study is the Feasibility Study and Conceptual Design for the Caparo
River Basin Flood Mitigation and Water Supply Project (in short: Caparo River Basin Study) by the
same consortium, as this concerns the river that may be used as a source of surface water for the
Felicity pilot site. The results of these studies will be available sometime during the course of next
year (2014). It is recommended to use the final results of these studies to fine-tune the design for the
Felicity pilot area, and to refer to these studies when deciding to implement other irrigation schemes
based on the Felicity pilot design.
Meanwhile a very constructive dialogue and cooperation was established, in which the consultants
could discuss the irrigation water requirements of the Felicity Area with the Caparo River Basin Study
consultants and even at a workshop at Ministry level, to match overall water availability in the Caparo
Basin with demand from various stakeholders (mainly WASA). More details on the (preliminary)
results are given in Chapter 14, Options.
A comprehensive overview of the overall surface water availability, matched with projected irrigated
agricultural demands has been made in the study (MOP-1999-1B). The full annex was not available to
the consultants during the study. Table 13.1 shows the results of that study, indicating that at that time
and with the then used projections it was demonstrated that water resources would be insufficient in a
large proportion of the watersheds, including the Caparo River watershed.
8 The fact that it is very difficult to ensure adequate supply of irrigation water to the Felicity project
area shows that even in a basin with a supposedly relative abundant supply of surface water, irrigation is a challenge. For other areas, both inside and outside the Caparo Basin, the challenges are even larger.
56
Table 13.1: Water Availability per Watershed Based on 1999 WRMS
Source: (MOP-1999-1B)
13.2 Current, future and potential agricultural water resource needs
13.2.1 National situation irrigated areas
Reference is made to the report “The Development of Water and Waste Water Master Plan and
Policy for Trinidad, Chapter 21: Water Supply and Related Infrastructure Needs (WASA, 2008):
Irrigated agriculture is not presently a major water user in Trinidad or Tobago. The total current area
of irrigated agricultural land in Trinidad is estimated at about 3,050 ha9, with an estimated total water
demand of about 12 MCM10
per year.
Irrigation in Trinidad involves small diversions from creeks and streams with built works by private
individuals. Gravity flow irrigation can be found on a small scale on the Aripo, Guanapo, and San
Juan Rivers, while the larger irrigation systems are on the Caroni and South Oropouche Rivers.
The largest irrigation system is the Caroni system. This system diverts water from the Caroni River to
service the surrounding rice fields. Other irrigation systems are small-scale and are located in St
George, Nariva/Mayaro, St Andrew/St David, Victoria, and St Patrick. The main sources of irrigation
water for the Caroni River Basin are San Juan, St Joseph and Caroni rivers.
Agriculture in Trinidad is mainly rain-fed since there is negligible irrigation infrastructure. Access to
water for agriculture purposes has to face extreme competition from the domestic, industrial and
service sectors, especially during the periods of drought.
Since there is no information available on the existing or proposed national/regional drainage or
irrigation infrastructure from WASA or Drainage Division, GENIVAR had difficulty to analysis the water
available for each farming location and to propose alternative water supply strategies (WASA, 2008-
21).
9 This figure comes up every time, it is also mentioned in the 1999 DHV study for the Ministry of Planning. A new
inventory is obviously needed. Note: hectares, not acres. 10
This translates to about 400 mm per year; it is not clear if this is net requirement and if it is only for the dry season.
57
13.2.2 Former Sugar Growing Areas – potential irrigation demand
The situation in the former sugar growing areas was well described in the Strategic Environmental
Assessment (SEA) of the Implementation of the National Sugar Adaptation Strategy for Trinidad &
Tobago (NIRAS 2009). Relevant parts of this report are quoted below.
As described in Chapter 3 the Caroni (1975) Ltd. enterprise was liquidated and the lands were to be
distributed and developed. There are three main alternatives for the Caroni (1975) Ltd. properties:
Agricultural, residential and industrial development. For the purpose of this study only the agricultural
lands are considered.
The agricultural lands are to be developed either as mega-farms which are commercial entities, or as
2 acre plots provided to 7000 former Caroni (1975) Ltd. Workers. These are currently underutilized
and are being considered for development as cooperatives in which the title holder would be able to
lease his land to a cooperative in return for a portion of the profits. The cooperative plans for the 2
acre plots are still under development (NIRAS 2009, Chapter 3.2).
Agriculture continues to be a principal development alternative proposed for the former sugarcane
lands at Caroni (1975) Limited. Of the 76,608 acres of available lands, 27% (20,319 acres) are
allocated for sub-division into two acre lots for former sugar workers as a part of their Voluntary
Separation, Employment Packages (VSEP). While estimated at approximately 7000 farmers, Caroni
workers will be recipients of these two-acre plots, and the precise number of beneficiaries remains to
be finalized.
Approximately 2,263 acres of land are allocated for the development of 13 commercial (mega) farms.
The lot sizes for this category of farms range between 100 acres and 267 acres. There are plans to
formalise the occupancy of several informal agricultural land settlers (squatters), who are currently
occupying 6% (4,222 acres), into legal land holders. It is not clear as to what arrangements are in
place to deal with some 11,109 acres (15%) that collectively grow citrus/tree crops, rice, livestock,
pasture and aquaculture under the former Caroni 1975 management structure. The future
arrangements of existing tenants, currently occupying 16 % (11,861 acres) need to be ratified as well.
A total of 16,703 acres (24 %) of the Caroni land are identified as residual lands since the closure of
the sugar industry and could be earmarked for meaningful alternative developmental activities (NIRAS
2009, Chapter 3.2).
To summarise the above: any consideration for irrigated agriculture is to aim at the mega farms (2129
acres) and the 2-acre plots (7305 total developed by 2009 (NIRAS 2009, Chapter 3.2)). As the mega
farms are flexible in the choice of crops it is not simple to estimate possible irrigation water
requirements. However, the methodology presented in this report can be used once the crops and
cropping patterns are known.
For the 14,610 acre in 2-acre plots it is assumed that a mix of vegetable crops will be planted during
the dry season (as well as in the rainy season), but this will depend on the availability of a reliable
source of irrigation water for the specific area. Another assumption that needs to be made is that the
farmers will use the irrigation water in an efficient manner. How this is to be achieved is explained in
Chapter 16, Design.
Irrigated rice is already established (in the lower Caroni basin), and described in (MoP 1999-6). No
evidence of plans for extension of the rice growing area was encountered, as the Ministry seems
acutely aware of the limited availability of water resources for irrigation.
13.2.3 Irrigation water requirements – approach
A comprehensive study into the irrigation water requirements as part of the overall national Water
Resources Management Strategy was carried out by (MOP 1999-6). The method used in this study is
explained in detail in Annex 10, Irrigation Water Requirement; it is based on the normal approach
described in (FAO, 1977) and applied worldwide.
58
13.2.4 Calculated irrigation water needs for the Felicity Pilot Area
Applying the theory outlined in Annex 10, the following steps are taken to calculate the gross volume
of irrigation water required for the Felicity Pilot irrigation scheme.
1. Determine reference crop evapotranspiration, ETh (Table 18.2) (a)
2. Apply crop coefficient: Vegetable kc of 0.73 to be used for the Felicity Pilot area.(b)
3. Calculate crop evapotranspiration (mm) per month for January-June
4. Calculate effective precipitation (Table 18.4). (c)
5. Estimate the irrigation efficiency at scheme level: 65-70% (75% for tertiary/field application, 90%
for the secondary distribution system) (d)
6. Calculate the net irrigation requirement IR per month (mm)
7. Add leaching requirement or ensure that this is covered in the irrigation losses + rainfall11
8. Calculate net irrigated area (gross area less 5% for infrastructure)
655 2 acre plots = 530 ha – 26 ha (on farm ponds) = 504 ha
9. Calculate the volume of irrigation water requirement per month for the entire area Vscheme
10. Estimate losses for the conveyance from the source of irrigation water to the Felicity Pilot
Scheme intake/distribution works (pipe: 5%; river: range from 10-20% depending on illegal water
abstraction upstream.
11. Calculate the total required volume of irrigation water Vprimary
12. Repeat 3 to 11 for the selected values for climate change scenario 2050 (Table 13.3, Table
13.4).
The results of the calculation for 2013 are shown in Table 13.2. An explanation of the parameters and
the datasets used is given below the table.
Table 13.2: Irrigation water volume for Felicity Pilot irrigation scheme, 2013
Parameters / datasets used for the 2013 scenario
1975-1995 meteorological data from Piarco. Average monthly values, corrected for temperature trend to 2013 based on (MOP 1999-6)
11
For the Felicity area it is assumed that the leaching requirement is met by the rainfall surplus and the losses at tertiary level; this is under the condition that drainage is good / adequate. See also the Chapter on Flooding and Drainage and Chapter 15 (Design).
Month
January 3.9 0.73 2.8 87.7 15.2 72.6 541.7 601.8 570.2
February 4.5 0.73 3.3 91.0 11.6 79.4 592.8 658.6 624.0
March 4.9 0.73 3.6 111.6 6.9 104.7 781.9 868.8 823.1
April 5.1 0.73 3.7 111.5 7.2 104.3 778.9 865.4 819.8
May 4.9 0.73 3.6 109.9 24.9 85.0 634.3 704.7 667.7
June 4.1 0.73 3.0 90.8 61.1 29.7 221.5 246.1 233.1
July 4.2 0.73 3.1 94.2 69.8 24.4 182.4 202.7 192.0
August 4.2 0.73 3.1 93.5 69.6 23.9 178.4 198.2 187.8
September 4.2 0.73 3.1 90.0 52.9 37.1 277.3 308.2 291.9
October 4.0 0.73 2.9 86.6 45.9 40.7 303.8 337.5 319.8
November 3.7 0.73 2.7 76.2 58.3 17.9 133.3 148.2 140.4
December 3.6 0.73 2.6 76.5 32.3 44.2 329.7 366.3 347.1
Dry Season 512 446 3329 3699 3505
Total 1120 456 664 4956 5507 5217
ETh
(mm/d)
kc
ETc
(mm/d)
P e
(month)
IR
(mm/m)
V primary
Pipes
(1000 m3
/ month)
ETc
(month)
V scheme
(1000 m3
/ month)
V primary
Caparo
(1000 m3
/ month)
59
1971-2010 rainfall data Piarco, 75% monthly rainfall (MFPLMA, 2011); reduced by 10% for Felicity area based on the isohyetal map of Trinidad (WASA, 2008-21); adjusted for climate change outlook (only wet season, 6.1mm decrease monthly average rainfall per decade (Table 18.2)).
Vscheme: efficiency tertiary at 75%, secondary at 90%
Correction T (temperature, max and min): average of 1975-1995 is 1985; difference with 2013 is 28 years. This means that the average of 1975-1995 is to be corrected with: 0.672 °C (28 years x 0.024 °C).
Correction Pe: The midpoint of 1971-2010 is 1990; the difference with 2013 is 23 years. An estimate of the factor between average and 75% rain is 0.74 for June-December. This means that the Pe of 1971-2010 is to be corrected with -10.4 mm for each month of the wet season (here taken as June-December)
12.
Vprimary: efficiency primary conveyance at 95% (pipe) or 90%-80% (Caparo River).
Parameters explained
ETh Reference Evapotranspiration (based on Tmin, Tmax, relative humidity (average), wind, sunshine, all as monthly values, see Table 18.2); mm/day.
kc Crop coefficient: ratio of given crop to ETh, taken as 0.73 for vegetables.
ETp Potential Crop Evapotranspiration kc x ETh, mm/d and mm/month
Pe Effective precipitation, mm/month
IR Irrigation Requirement, mm/month
LR Irrigation Requirement, mm/month
Vscheme Irrigation Volume for net irrigated area of the Felicity Area, including tertiary and secondary efficiency (75% and 90% respectively for spray pipes and piped conveyance)
Vprimary Irrigation Volume for net irrigated area of the Felicity Area including conveyance losses primary system efficiency (95% pipeline, 90%-80% Caparo River)
The resulting irrigation water requirement for the Felicity Area for 2013 is presented in Table 13.2 and
Figure 13.1.
13.2.5 Future and potential water needs
Climate change effects are not taken into account in the calculation presented in Chapter 13.2.4. In
general the parameters that determine ETh are subject to change due to projected climate change,
especially the temperature, and this means that the ETh is expected to become higher in the future.
Likewise it is expected that the rainfall during the dry season will stay the same, while the monthly
average rainfall volumes will decrease. The Pe, the effective rainfall available for the crops will thus
decrease during the rainy season. This effect is considerable, and higher than the effect of rising
temperatures on crop evapotranspiration.
As the GoRTT has not decided on a policy regarding which of the IPCC scenarios and which
downscaling values to use the consultants have selected a likely set of climate change outlooks for
selected parameters.
The consultants advise to use the following figures (Table 13.3) as best figures to work with:
Temperature: increase of on average 0.24°C per decade. Precipitation: decrease only during wet
seasons of on average 6.1 mm per month per decade. The precipitation for the dry season is not
12
This is based on the assumption that the recommended trend based on the selected climate change scenario (see Chapter 9.2) started already in 1971, the start of the rainfall data series used in this study. However, in : MFPLMA, 2011 the trend for average yearly rainfall data appears to be flat. If the correction is not applied this will result in a significant reduction (10%) of the calculated water requirement.
60
expected to change significantly (McSweeney, 2008). Note that this decrease is a decrease of the
average. No guidance on wind, humidity and sunshine was available, so for the 2050 scenario these
are kept the same (Table 18.2). For more details see Chapter 9, Climate and Climate Change.
The resulting irrigation water requirement for the Felicity Area for 2050 is presented in Table 13.5 and
Figure 13.1.
Figure 13.1: Felicity Scheme Irrigation Requirements, 2013 and 2050 (mm/month)
Table 13.2: Crop Water Use Parameters - Climate Change adjusted
Year
Parameter
2050
Maximum Temperature (oC) +0,24° per decade
Minimum Temp (oC) +0,24° per decade
Mean Rel. Humidity (%) no guidance
Mean Wind velocity (km/day) no guidance
Sunshine hours (h)
Precipitation (mm) dry season
no guidance
no change expected
Precipitation (mm) rainy season 6.1 mm decrease per decade per month
0.0
20.0
40.0
60.0
80.0
100.0
120.0
Sch
em
e Ir
riga
tio
n R
eq
uir
em
en
t (m
m/m
on
th)
2013 irrigation
2050 irrigation
61
Table 13.3: Climate Change Adjusted Reference Crop Evapotranspiration for 2050
Table 13.4: Irrigation water volume for Felicity Pilot irrigation scheme – 2050
Parameters / datasets used for the 2050 scenario
1975-1995 meteorological data from Piarco. Average monthly values, corrected for temperature trend to 2050 based on (MOP 1999-6) (Table 13.4).
1971-2010 rainfall data Piarco, 75% monthly rainfall (MFPLMA, 2011); reduced by 10% for Felicity area based on the isohyetal map of Trinidad (WASA, 2008-21); adjusted for climate change outlook (only wet season, 6.1mm decrease monthly average rainfall per decade (Table 18.2)).
Vscheme: efficiency tertiary at 75%, secondary at 90%
Maximum
Temp
Minimum
Temp
Sunshine
hours
ETh
(oC) (
oC) (h) (mm/day)
January 31.2 22.0 78.6 112.9 7.7 3.8
February 32.0 22.1 74.4 128.4 8.1 4.4
March 32.8 22.7 70.8 151.1 7.8 4.9
April 33.4 23.4 69.8 150.9 7.7 5.0
May 33.2 24.3 73.4 151.1 7.4 4.8
June 32.3 24.5 78.5 128.8 6.0 4.1
July 32.5 24.4 80.0 108.9 6.5 4.1
August 32.8 24.5 81.8 90.0 6.5 4.1
September 33.3 24.2 79.9 89.5 6.5 4.2
October 33.1 24.2 79.1 86.7 6.3 3.9
November 32.4 23.8 79.7 87.6 6.4 3.6
December 31.7 23.0 76.6 98.2 6.7 3.5
Year 32.5 23.6 76.9 115.3 7.0 1531
Month
Mean Rel.
Humidity
(%)
Mean
Wind
velocity
(km/day)
Month
January 4.0 0.73 2.9 89.8 15.2 74.6 557.1 619.0 586.4
February 4.6 0.73 3.4 93.1 11.6 81.5 608.2 675.8 640.3
March 5.0 0.73 3.7 114.1 6.9 107.2 800.5 889.4 842.6
April 5.2 0.73 3.8 113.9 7.2 106.7 796.7 885.2 838.6
May 5.0 0.73 3.7 112.3 25.0 87.3 651.7 724.1 686.0
June 4.2 0.73 3.1 92.8 44.6 48.2 360.0 400.0 379.0
July 4.3 0.73 3.1 96.3 53.2 43.1 321.5 357.3 338.5
August 4.3 0.73 3.1 95.5 53.1 42.4 316.8 352.0 333.5
September 4.3 0.73 3.1 91.9 36.3 55.6 415.3 461.5 437.2
October 4.1 0.73 3.0 88.4 29.3 59.1 441.1 490.1 464.3
November 3.8 0.73 2.8 78.0 41.8 36.2 270.6 300.6 284.8
December 3.7 0.73 2.7 78.2 15.7 62.5 466.5 518.4 491.1
Dry Season 523 457 3414 3794 3594
Total 1144 340 804 6006 6673 6322
ETh
(mm/d)
kc
ETc
(mm/d)
P e
(month)
IR
(mm/m)
V primary
Pipes
(1000 m3
/ month)
ETc
(month)
V scheme
(1000 m3
/ month)
V primary
Caparo
(1000 m3
/ month)
62
Correction T (temperature, max and min): average of 1975-1995 is 1985; difference with 2013 is 28 years. This means that the average of 1975-1995 is to be corrected with: 0.672 °C (28 years x 0.024 °C).
Correction Pe: The midpoint of 1971-2010 is 1990; the difference with 2013 is 23 years. An estimate of the factor between average and 75% rain is 0.74 for June-December. This means that the Pe of 1971-2010 is to be corrected with -10.4 mm for each month of the wet season (here taken as June-December).
Vprimary: efficiency primary conveyance at 95% (pipe) or 90%-80% (Caparo River).
Other possible future increases
An extension of the irrigated area will of course mean that more irrigation water is needed. It is
strongly recommended to dimension the main infrastructure that conveys the water to the project area
(primary system) as large as practically and economically feasible. In fact it should be considered to
dimension this infrastructure based on a relatively optimistic estimate of the (future) water resources
available for irrigated agriculture.
Changes in crops: as indicated earlier in this chapter it is assumed that crops will only become more
water-efficient, and it is also assumed that irrigated rice cultivation or aquaculture will not be
introduced. The effect of any change of crops will thus be neutral or mean less consumption of
irrigation water.
13.3 Irrigation Sector Study – Concluding Remarks
1. Alternative preliminary layouts of the scheme are generally prepared, including size and shape of
commanded areas, water level and flow control, and location and size of required engineering
works. This approach has also been followed in the Felicity Pilot area, though the overall plots
and layout of the land was given. Several alternatives for supplying the required irrigation water
were evaluated (Chapter 14, Options).
2. In formulating the project, a thorough study of the engineering alternatives is required in order that
the most appropriate technical, managerial and economical solution is achieved.
3. Land ownership, natural boundaries, land slope and land preparation including land levelling must
be reviewed in relation to the scheme layout. For Felicity it is assumed this has been done
correctly, as the lay-out of roads, plots and drains was in place when the consultants arrived.
Feasibility of land consolidation, where needed, should usually be considered from the legal,
technical, economic and particularly sociological point of view, though in the Felicity case this is
probably not very relevant; only limited legal issues (access to the land for building irrigation
infrastructure) need to be addressed.
4. Accurate evaluation of future project operation and water scheduling (for replication of the pilot
design in other areas of the former sugar growing lands) cannot be made unless pilot projects are
operational. No scheme functions perfectly the day it becomes operational. Allowance should be
made in the planning and design to account for changes in cropping pattern and intensity, at the
same time avoiding any excessive over-dimensioning. Refinements of irrigation scheduling to
match crop irrigation needs should he made after the project has been in operation for some
years.
5. For the estimate of the overall water availability for irrigated agriculture it is not feasible to go
beyond the studies done by DHV in 1999 at this stage. The projected increase in irrigated
agriculture has not been realised; it even appears that the total area under irrigation is lower than
in the 1980’s. It is recommended to reconsider the aim of increasing the area under irrigation to a
realistic target figure set for only 5 years ahead, and to consider options for irrigation on a case by
case basis, matching available water resources with demand for the potential irrigation schemes,
and taking into account the capacity of the agricultural extension service and the availability of
63
budget for implementation of infrastructure works. Individual schemes need to be identified, which
means that it is not possible to indicate a target area at this stage. Further study is recommended.
6. The need for irrigation water during the wet season means that the natural flow of the rivers
becomes an important factor; infrastructure to utilise water from these streams will have to be
included in the mix of water resources for irrigation.
7. Climate change will increase the dependence on irrigation, slightly during the dry season but
more significantly during the wet season.
8. It is normally recommended to take the social aspects of water management into account when
designing an irrigation scheme layout. The layout will influence and can facilitate the functioning
of water user associations. In the Felicity Pilot area the plot lay-out and main infrastructure is
already given; this limits the freedom for the design.
9. The hydrology of the Caparo River has been extensively studied and is being studied by the
ongoing Feasibility Study and Conceptual Design for the Caparo River Basin Flood Mitigation and
Water Supply Project (in short: Caparo River Basin Study), as this concerns the river that may be
used as source of surface water for the Felicity pilot site. The results of these studies will be
available sometime early next year or during the course of next year (2014). It is recommended to
use the final results of these studies to fine-tune the design for the Felicity pilot area, and to refer
to these studies when deciding to implement other irrigation schemes based on the Felicity pilot
design.
10. For the effective precipitation a decision has to be made on whether to use 1:4, 1:5 or 1:10 year
confidence values, e.g. the expected minimum rainfall in 75%, 80% or 90% of the cases. In the
years that this rainfall limit is not reached crop yield reductions caused by sub-optimal availability
of irrigation water may occur. In this study the available 1:4 or 75% precipitation dataset (1971-
2010, Piarco, monthly values) has been used. Higher confidence values will result in (even)
higher irrigation requirements, and 1:4 or 1:5 are commonly accepted in irrigation design practice.
11. While the subject of this chapter is irrigation, the consultants want to stress irrigation cannot be
seen separately from drainage and leaching. In the long run, if not already from the beginning,
irrigation requires drainage. For Felicity the field application losses that are included in the design
irrigation water requirement together with the (average) rainfall surplus during the rainy season
deliver enough water of reasonable to good quality to remove any accumulated salt from the soil;
however, this flux needs to be evacuated. The risk of salinisation and eventually (hard to reverse)
damage to the soil is certainly present if re-use of drainage water is considered, if too much
irrigation water is applied (over-irrigation, water logging, and often salinisation), or if the (local)
drainage situation is inadequate, but also when under-irrigation is practised (salinity build-up).
Climate change, with lower rainfall during the rainy season, will also increase this risk. It is
strongly recommended to establish a 5-yearly audit of the drainage and salinity situation in the
project area, and to establish a monitoring network in the irrigated area. Preventing soil
salinisation is relatively easy and inexpensive; regeneration of a salinised soil is very costly and
time-consuming.
64
14. OPTIONS FOR IRRIGATION
14.1 Introduction
For successful introduction of irrigation in the Felicity Pilot area a relatively large quantity of irrigation
water is required (Table 14.1, some 700 mm during the dry season, up to 1000 mm over the entire
year for the 2013 situation). The quality of this water has to meet a set of criteria regarding the
presence of (human) sewage and other pollutants, and salinity.
In this Chapter the various options, or water resources, are identified. The description of the various
options is sometimes qualitative, but where possible quantitative. The reader is referred to previous
chapters in this report when relevant.
The process to identify the most promising solution is done in two stages. First the identified potential
irrigation water resources are evaluated against the following criteria:
- suitability for providing sufficient water in the dry season and during the rainy season;
- suitability for appropriate water quality in the dry season and during the rainy season;
- risk of salt water intrusion and soil salinisation (see also Chapter 11.2, 12.5 and 16).
- environmental impact of irrigation water on the project area and downstream.
In the second stage the preferred options are evaluated taking into consideration factors like: Water
availability, other claims on the water, conveyance losses (primary system ), water quality, land loss
for infrastructure, salt water intrusion (groundwater), cost, robustness, O&M costs and environmental
impact (Table 14.2).
Complicating the search for possible water resources is the competition with (domestic) water supply
(WASA), and possibly industrial use. It is recommended to develop and follow a very clear policy
which outlines the distribution of water in times of water scarcity. While under almost all
circumstances the provision of drinking water will always take precedence over agricultural water use,
the domestic supply sector should shoulder a reasonable part of the effort to save water, by reducing
water use (and wastage) and possibly by introducing rationing. Cutting off the entire supply to
agriculture from a shared water supply should only take place under exceptional circumstances.
Management of such shared resources should be aimed at optimising the dual use of the resource.
14.2 Possible irrigation water resources
The consultants have identified four possible sources for dry season irrigation water supply:
1. The Caparo River13
in the project area;
2. Groundwater abstracted in or close to the project area;
3. Upstream reservoirs and conveyance of water to the project area:
a. Large existing, flooded mining pits east of the project area, adjacent to the Caparo River;: the
Ravine Sable Sand Pits (RSSP)
b. The Caparo River dam (Mamoral), formerly only planned for flood protection, now under
consideration as multi-functional reservoir;
c. Abels Clay Pit, now still being mined under a current license.
4. Treated wastewater re-use and drainage water re-use:
a. Conveying treated wastewater from outside the project area directly to the project area;
b. Within the project area, by collecting the outflow /drainage and re-using it by mixing it with the
selected irrigation water source(s) – closed loop
Combinations of more than one of the above water sources can (and have to) be considered.
13
Another river borders the Felicity project area in the south, the Chandarnagore River. However, from information received by the consultants in discussions it is doubtful that this river can contribute in any significant way to the irrigation water requirement. If this option is to be included a further study of the potential discharge of the Chandarnagore River is needed.
65
1. Caparo River
Rainy season (supplementary irrigation)
During the rainy season there is generally enough water in the Caparo River to cover the irrigation
water requirements. Crop water demand is mostly – but not completely and not dependably14
– met
by rainfall. Because of the relatively large discharge in the Caparo River during the rainy season the
water quality is relatively good as pollutant loads are much diluted. In general it can be stated that the
irrigation water requirement for the Felicity Area can be met using the water in the Caparo River at the
point where it enters the project area. This amount has to be clearly claimed in a water abstraction
license / water abstraction licenses, to prevent later developments upstream from endangering the
irrigation in the Felicity area.
The remaining challenge is to ensure that occasional prolonged dry spells, especially those linked to
the ‘petit careme’, are bridged. The hydrologic records of the Caparo River show that even during the
rainy season the flow can quickly decrease to very low volumes after just a few dry and sunny days,
see Figure 14.1. Some sort of water storage is needed to protect the crops from suffering damage
due to lack of water.
Illustrating the need for access to irrigation water during the rainy season was the observation by the
consultants that the farmers were taking water from the Caparo River in July 2013. They were using
low-lift low pressure pumps and spray-pipes – apparently additional irrigation was still required,
though it may also be that the farmers used the system for efficient fertiliser application.
Dry season (“full” irrigation)
Problems arise when large volumes of irrigation water of adequate quality are required during the dry
season. During this season the discharge of the Caparo River is almost always as low as to be
negligible, the flow is unreliable and the water quality is (very) poor, due to the disposal of (untreated)
domestic and other wastewater into the river. In effect, unless it rains, the entire flow of the Caparo
River can be considered wastewater. This means that the Caparo River under natural flow conditions
is not very suitable as source of irrigation water during the dry season (see Figure 14.1 for an
example of a typical year). Only in the absence of other viable alternatives the Caparo River should
be considered as a source for irrigation; and then only after rainfall has diluted the pollution. Additional
measures to prevent contamination of crops have to be taken.
14
See Chapter 13: Irrigation Sector Study for the former sugar growing area – irrigation water requirement.
66
Figure 14.1: Caparo River, daily discharge at Todds Road, 2001
(Source: NIDCO, 2013, Royal HaskoningDHV Caparo River Basin Project based on data from Water
Resources Agency, WASA)
2. Groundwater
The availability of groundwater in the project area is limited because of low permeability (quantitative
analysis: see Chapter 10.3 ‘Potential of Groundwater in the Project Area’). Furthermore, there is a risk
for saltwater intrusion in the project area, as it is situated near the brackish wetlands to the west
(Chapter 10.3). To abstract additional water from the nearby Carlsen Field Wells is no option,
because the well field is already overexploited.
Groundwater could be considered as a temporary additional water resource for emergency use.
However, first a hydrogeological study would be required; certainly related to the risk for saltwater
intrusion in the area. This option is not promising.
3. Use of upstream reservoirs
a. Large sand mining pits, (Ravine Sable) adjacent to the Caparo River
About 7 km due east of the project area is a group of large mining pits, known as the Ravine Sable
Sand Pits (RSSP, Figure 14.2). One of these is filled with water since a major flood in 2010 breached
the separation dam (actually an old railway dike) between the Caparo River and the pit. Another pit is
right next to it, connected at high levels, and easily connected at lower levels. Their combined volume
at full capacity is estimated at 3.0 million m3. The possibility to use these pits for flood management
and water supply is studied15
. A connection with a gated structure between the Caparo River and the
pits is being considered, to enable diversion of river water into the pits for storage and flood
management when required.
15
Feasibility Study and Conceptual Design for the Caparo River Basin Flood Mitigation and Water Supply Project, Royal HaskoningDHV, for NIDCO
67
Figure 14.2: Ravine Sable Sand Pits
(Source: NIDCO 2013)
(Source: GoogleMaps)
A clear advantage of using the RSSP as source for irrigation is the water quality. The source of the
water, the Caparo River, is still upstream of most populated area, the large city of Chaguanas. Also,
the storage will mostly fill during the rainy season when any remaining upstream pollution is diluted to
the maximum level.
There are two options to transport the water from the pits to the project area:
1. Pumping it back into the Caparo River
2. Building a dedicated pipeline
Considerations:
- The sand deposit is in an impermeable or very local aquifer as there is no connection with the two
rivers16
. Ravine Sable to the north-east and Caparo River to the south-west, with both rivers
within just 200 to 500 m from the sand pits. This means that there is probably none or little water
stored in the local aquifer, and that pumping this aquifer is no viable option.
b. The Caparo River (Mamoral) multi-functional dam
In addition to the mining pits a dam is planned on the Caparo River, a few kilometres upstream of the
sand pits17
. The reservoir this dam creates could also be taken into consideration as another potential
irrigation water reservoir. The dam is designed as multi-purpose reservoir, combining flood mitigation
and storage. If the dam is built the operation for water storage needs to be in combination with the
operation and management of the storage capacity of the sand mining pits.
Considerations for the Mamoral multi-functional reservoir and the Ravine Sable Sand Pits:
- The sand pits are considered for both flood mitigation and water supply; however, for effective
flood mitigation the projected Mamoral dam on the Caparo River upstream from the sand pits is
still needed. This would form another large storage reservoir (up to 2.8 Mm3). If this project gets
approval11
the management and allocation of water from both the sand pits and the dam reservoir
will need to be handled by one organisation, as one combined system.
- The combination of flood management (which needs emergency storage capacity) and water
storage for water supply / agriculture are often at odds. Careful management of the water level in
the pits (and possibly the Mamoral dam) is required. Dual use will normally mean that the
reservoirs will not be filled to capacity at the end of the rainy season.
16
Information from discussions with the consultants of the Caparo River Basin Project. 17
At a high-level workshop (attended by the Minister) at the Ministry of Environment on August 27 a consensus was reached that the advantages of building the Mamoral Dam may not offset the disadvantages. Studies also show that the production of the RSSP alone is quite large (estimate August 30: 12.7Mm
3/y) and construction of
the Mamoral Dam may not add much as the reservoirs are in series, not far from each other.
68
- A minimum base flow in the Caparo River will be required (environment), even though the Caparo
River now often runs dry in the dry season. This will also compete with the other water uses.
c. Abel’s Clay Pit
- Close to the Caparo River, only a few kilometres upstream of the Felicity area, a clay pit is
exploited. This pit could be a very useful reservoir, with a capacity of 1.75 Mm3. (NIDCO, 2013).
As the pit is still mined under a current license this is an option for future consideration.
4. Treated wastewater re-use
a. Directly by bringing treated wastewater from outside the project area
At this moment there are no treatment plants in the area that can deliver treated wastewater to the
Felicity irrigation area. This option needs to be kept open, to be considered for implementation if and
when a large treatment plant will be build, e.g. in Chaguanas Town, which is just upstream from the
project area. The application of treated wastewater should be considered as a source for irrigation
water when a reliable flow becomes available18
.
b. Within the project area, closed loop concept
With introduction of irrigation water, by definition increased drainage losses will result.
Drainage losses from one system may add to the available supplies for other downstream users - or
may be re-used in the same system. Overall efficiencies can thus be higher than efficiencies for
individual irrigation schemes without use of these drainage losses. The return flow is defined as the
percentage of the gross irrigation requirements which will return to the surface water system. For most
schemes a return percentage of 30 per cent is used, for sprinkler irrigation and the relatively efficient
irrigation at the Caroni (1975) Ltd Rice Farm a value of 20 per cent is used. This means that it is
assumed that for the Felicity Area system 20 per cent of the gross irrigation requirement will return to
the system (adapted from DHV-6, 1999).
The re-use drainage water is markedly more saline than the original irrigation water. This is caused by
concentration of the original salt content; the plants do not take up the salt, which is leached away into
the drains. The salt content is thus expected to be multiplied by 5 (1/20%) as all salt is expected to be
leached out. In addition excess fertiliser and excess pesticides will end up in the drainage water.
Introducing the ‘closed loop’ system means that this drainage flow can be collected at the
downstream part of the project area, and pumped back to the irrigation water inlet, to be mixed back
with the ‘fresh’ irrigation water.
This approach has a number of advantages:
1. It reduces the net irrigation water requirement (the ‘fresh’ irrigation water volume);
2. Any fertiliser that was washed out will be re-applied, reducing the need for new fertiliser and
saving money;
3. Pesticides will not spread further downstream of the project area.
Disadvantages are:
1. The infrastructure of the irrigation and drainage system may have to be adjusted, as the
concept of closed loop re-use was not a boundary condition for the design of the present
drainage system. Some kind of reservoir at the downstream end of the drainage system is
required;
18
Due to time constraints the consultants did not consider the option of utilising treated industrial effluent from the facilities at Point Lisas Industrial Estate. This is a concept that can be examined since the Point Fortin Desalination Plant currently supplies approximately 100,000 m³/day to these industries and the effluent released from the operations at the facilities can be considered as a source of irrigation water upon treatment.
69
2. Pumping means operation and maintenance of a pump or a set of pumps, and the
construction of a pipeline.
3. Pesticides could build up in the soil and possibly the crops by continuous recycling.
4. Due to the increased salinity of the mixed irrigation water an increased irrigation application is
needed, partly negating the advantage of lowering the fresh irrigation water volume (e.g. the
‘leaching requirement’).
5. The soil needs to be closely monitored for signs of salinisation, as the risk of salinisation
increases with application of a more saline mix of irrigation water.
In fact, closed loop re-use is an option that can be applied to any combination of other sources. The
effect of this option will thus be evaluated in combination with the selected option(s). Implementation
of this option can be decided separately, as a ‘module’ to the selected design option, although it will
have effects on the volume of ‘fresh’ irrigation water that is needed; the volume of re-use water cannot
simply be subtracted from the amount of needed ‘fresh’ irrigation water.
A closed loop system cannot reduce the total amount of salt that eventually leaves the project area,
as it is not possible for this salt to accumulate indefinitely. The salt balance should equal zero over a
year or, in exceptional cases, possibly a few years. The main gain in applying the closed loop system
is that it gives the possibility to choose when to discharge / leach the salt and evacuate it out of the
irrigation system. This can be timed to coincide with a period of sustained rainfall and high
discharges, to dilute the pollutant and salt load of the drainage (and eventually river) water.
5. A combination of possible water sources
A total irrigation volume of about 715 mm19
is needed for the dry season months of January up to and
including May. This translates into a volume of 3.6 Mm3. The maximum flow
20 under optimal
management of the on-plot ponds will then be 170-175 l/s. The only source of water for this kind of
volume is the Ravine Sable Sand Pits reservoir.
The estimated average production of this reservoir is about 400 l/s (NIDCO, 2013, Royal
HaskoningDHV). A preliminary optimization shows that the requirements for irrigation at Felicity and
the stated requirements for WASA can be met during the entire year (only 2 days with 5 l/s deficit),
see Figure 14.3 (2013) and Figure 14.4 (2050).
Figure 14.3: Simulation water requirements WASA and Felicity Irrigation at Ravine Sable Sand
Pits, 2013
19
Including all losses in the primary, secondary and tertiary system, including climate change expected for 2050. For 2013 the amounts are 695 mm and 3.6 Mm
3, see Chapter 13 and Annex 10.
20 Taking only 5% losses in the primary system, the conveyance to the Felicity Area.
70
Figure 14.4: Simulation water requirements WASA and Felicity Irrigation at Ravine Sable Sand
Pits, 2050
For the projected situation in 2050 this is different, though the type of optimization cannot easily be
compared with the design criterion of 1:4 year21
.
Assumptions made for the simulation
The Caparo River flow series received from WRA is only 15 years. This is not a continuous series, it is
1989 to 2007 but 1994, 1996, 1997 and 1999 are excluded due to missing data. The resulting 15 year
series is applied as a continuous series.
The discharge diverted from the Caparo River to the RSSP is variable.
Statistically speaking this analysis cannot be assigned to a certain return period; however, it gives a
very good idea on the overall availability of water for WASA and agriculture / irrigation in the Felicity
area.
Rainfall, evaporation and deep losses into and from the RSSP are included in the calculation, based
on a variable surface area of the RSSP as function of the water level (area-elevation curve).
The maximum level is taken at 30 m +MSL, which is the result of optimisation of the water
requirements. Much higher does not really add to the water availability. From the ‘bottom’ to the 26m
+MSL excellent Elevation-Area-Capacity relations are available (LiDAR based); above that level the
relations are extrapolated, these will be determined more accurately using GIS. The volume can still
be adjusted by further excavation / sand mining.
In addition the Felicity water demand has been allowed to range from 90-100%, because otherwise
deficits would start to add up at the end of the dry season22
.
Flood detention in the RSSP will be in the layer from 30 to 32 m +MSL; this water needs to be
released as quickly as possible after a flood event but this is not important for WASA and the Felicity
21
The optimisation of the operation of the RSSP (preliminary) was done by applying the flow records of the Caparo River for 15 years, and this shows that the 2013 Felicity irrigation requirement and the stated WASA requirement can be met. 22
This means that buffering in the on-plot ponds in the dry season should be actively pursued, and the simulation should be run again with ranges from 90%-110% to allow buffer replenishment.
71
irrigation area. The flood mitigation analysis, linked with the effects of river channel widening, will be
modelled and simulated later using Sobek (Hydrodynamic model).
While this analysis is preliminary, the consultants of Royal HaskoningDHV are confident that the
results give a good representation of the actual situation.
Please note: the results are preliminary; they have to be reported to and agreed with NIDCO/DrainDiv (planned
for 8 October), and limited adjustments may be made, like the maximum level of the RSSP, or limitations in the
volume of the RSSP when modifications of the RSSP are included in the simulation.
With thanks to NIDCO and the consultants of Royal HaskoningDHV, for an example in inter-project cooperation.
14.3 Irrigation system in the Felicity Area – assumptions
14.3.1 Irrigation efficiency
The evaluation of the options in this chapter is based on the prior assumption that irrigation in the
Felicity Area will be based on low-lift low-pressure pumps, rigid distribution pipes and flexible ‘spray
pipes’. The irrigation efficiency of the secondary system (e.g. to get the water from where it enters the
Felicity area to the farmer plots) is taken at 90%23
, which is based on pipes. The irrigation efficiency at
tertiary level is taken at 75%. By considering 25% primary losses it is assumed that leaching
requirements are met.
14.3.2 Irrigation ponds
Small on-site irrigation ponds have been constructed on a number of plots in the Felicity Area. The
dimensions are 20x20m with a depth of 4.5m, the maximum stored volume24
is about 1700-1800 m3.
This means that a pond takes up 5% of the gross area of one plot18
. If the water of a pond is used for
one plot only, and if the pond is full at the start of the dry season, a total gross irrigation depth of
about 200mm is available. This is not insignificant25, as it will cover four to six weeks of dry season
irrigation water requirement, see Table 14.1.
Unlike the pond used for irrigation and domestic water supply at Depot Road, there is no
inflow/recharge of groundwater in the ponds in the Felicity Area. This means that the supply of water
has to come either from direct rainfall (thus creating a buffer, which is very useful in the rainy season
to bridge dry spells) or from another source. The relatively heavy clays, which prevent direct
contribution from groundwater, have the advantage that they prevent leakage losses. However,
losses from direct evaporation from the pond surface should be considered when calculating the
available irrigation water. Ponds are not a source of irrigation water, although at the start of the dry
season a surplus from rainfall may well have accumulated.
For the ponds to be useful during the dry season there needs to be a system to replenish them from a
water source other than rainfall. Also, a pond has to be constructed at every plot, or larger ponds are
to be constructed that service a number of plots. Construction of larger ponds has the clear
advantage that the system to replenish the ponds can be much simpler. The disadvantage is that
individual farmers cannot control or see exactly who uses how much of the water, possibly leading to
disputes and water wastage (‘tragedy of the commons’). Unless a very clear mechanism to control the
use of pond water can be devised, set up and enforced (metering the outflow?) it is recommended to
build ponds on all individual plots, unless adjacent plots are farmed by one farmer or cooperative.
23
Based on experience, good practice and FAO, 1984 24
From new information received during the last days of the project the dimensions of the on-farm ponds are such that the actual water held is lower, and the land used is more – according to one source up to 9% of the plot area 25
Reports from farmers that a pond holds only enough water for one irrigation should be checked; possibly they overirrigate the crop, or most probably, the water from one pond is used for several plots.
72
Table 14.1: Irrigation water requirement (including losses)
Vscheme (1000 m3 / month) (mm/month) Flow (litre/s)
Month 2013 2050 2013 2050 2013 2050
January 544.9 560.5 113.1 116.4 170 170
February 596.3 611.9 123.8 127.0 170 170
March 786.6 805.3 163.3 167.2 170 170
April 783.6 801.5 162.7 166.4 170 170
May 638.1 655.7 132.5 136.1 170 170
June 222.8 362.2 46.3 75.2 170/85 170/135
July 183.5 323.5 38.1 67.2 85 135
August 179.5 318.7 37.3 66.2 85 135
September 279.0 417.8 57.9 86.7 110 135
October 305.6 443.8 63.4 92.1 110 170
November 134.1 272.2 27.8 56.5 110 170
December 331.7 469.3 68.9 97.4 110 170
Dry season
3350 3435 695 713
Total 4986 6042 1035 1255
(Source: see Chapter 13 and Annex 10, Irrigation; Flow is at the Ravine Sable Sand Pits)
The ponds are thus essential for buffering irrigation water: to bridge dry spells in the rainy season,
and to ensure that the farmers have an ‘insurance’ if the outside water supply is cut. Figure 14.5 and
Figure 14.6 show examples of how the water levels in the ponds fluctuate during the year. It is clearly
shown how the level is allowed to gradually drop during the dry season, to recover again during the
rainy season. At the end of the rainy season the ponds should all be filled to capacity. Different ponds
will have different filling dates, and may even have different volumes delivered.
Figure 14.5: Dynamic water level on-plot pond during the year, situation 2013
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 5 10 15 20 25 30 35 40 45 50
Po
nd
leve
l mm
week
Pond level - 2013
depth ponds refill
dry season 6000 mm filltotal 13400 mm fill
73
Figure 14.6: Dynamic water level on-plot pond during the year, situation 2050
If the Ravine Sable Sand Pit is selected as primary water resource for the Felicity Area and if the full
irrigation water requirement can be sourced from there, it is recommended to install a pressurised
pipe system for distribution of the irrigation water at the secondary level (within the Felicity area).
It would appear that in this case no ponds are needed, freeing up another 5% of irrigable land (for
which irrigation water needs to be brought in). However, the disadvantage is that the management of
this system is much more complex and the robustness is much lower, with less responsibility for the
farmers and much more for the GoRTT. Even more important: the 1 Mm3 of storage within the Felicity
Area is absolutely essential26
. In the opinion of the consultants leaving out the on-farm ponds is not
viable.
14.3.3 Water metering
As the supply of irrigation water is limited, it should be applied correctly. Any wastage should be
avoided. Training and instruction of the farmers is an essential part of any water conservation effort.
However, experience worldwide shows that farmers will start using water economically only if it has a
price, like any other farm input.
This means that some way of metering or measuring the water use of the farmer needs to be
implemented. If water is delivered by a fine network of pipes, water meters can be installed at
individual off-takes. Another method is to check the level of the ponds before filling them, and thus
calculating the water delivered to the farmer. If electrical pump units are used, the electricity use is a
good indicator for the pump hours, which then give a good approximation of the volume of water
used.
Finally, the preferred option: the system of valves to fill the on-farm ponds is operated by a person
who sets the inlet valves at a set time of the day, say 9am, at such a level that 0.5, 1, 1.5 or 2 meter
of additional water is supplied to the pond in 24 hours. This setting, together with the level in the pond
and the electricity meter reading, is recorded (smartphone).
26
Smaller ponds are possible and explored in the Design Annex. This means that a larger area of Large Buffer Ponds is required.
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 5 10 15 20 25 30 35 40 45 50
Po
nd
leve
l mm
week
Pond level - 2050
depth ponds refill
dry season 6000 mm filltotal 16161 mm fill
74
14.4 Selection of preferred option
To evaluate the options and to come to the most optimal mix of water resources an evaluation matrix
of the different options is made, Table 14.2. In this table a list of different criteria is tested, and while it
is difficult to assign weight (as importance) to the different criteria, the matrix still gives a good
overview of advantages and disadvantages of the different possible water resources.
Some criteria can be seen as absolute requirements: the fact that only very small volumes appear to
be available from groundwater means that this will still not be a viable proposition. Likewise, the high
scores for the Sand Pit reservoir and the Mamoral Dam Reservoir will be completely useless if no
water from these two sources is allocated to irrigated agriculture, or if the Mamoral Dam is not built.
The Caparo River scores low, while this is the only form of irrigation water presently used by the
farmers in the Felicity area.
An analysis and evaluation of options, and a selection of a feasible solution, can thus only take place
based on an overall view of combinations of resources. It is necessary to use those resources in such
a way that the most positive characteristics are combined in an optimal mix.
Another important consideration that may not be clear from the matrix is that it is recommended to
work as much as possible with the infrastructure that is already in place. Making large changes will be
expensive, and disruptive to farmers who are already working the land, and even irrigating the land.
By adapting, improving and adding to their present practices the transition to the new system can be
expected to be much easier, as the acceptance will be much higher. Still, it is imperative to involve the
farmers and other beneficiary stakeholders during all steps of the decision making process.
75
Table 14.2: Evaluation matrix of options (dry season) – irrigation water resources
Resource
Criterion
weight
Caparo
River
Ground
water27
Sand pits,
pipes
Mamoral28
Reservoir,
pipes
Sand pits
Caparo,
River
Mamoral22
Reservoir,
Caparo
River
Water availability29
2x ++ 0 ++++ ++++ ++++ ++++
Other claimants 1x + + - - - - - - - -
Water quality 1x - - ++ ++ ++ ++
Salt water intrusion 1x o - - ++ ++ ++ ++
Robustness 1x - + o o o o
O&M costs30
1x - o - - - -
Environmental impact 1x - - ++ ++ ++ ++
Conveyance losses
(primary system31
) 1x + + ++ ++ - - - -
Obstacles for
construction 1x + o - - - - - -
Cost32
1x o + - - - - - - - -
Total33
+ o +++++ +++++ ++ ++
Key: - - negative; - somewhat negative; o neutral, no effect; + somewhat positive; ++ positive.
Based on the description of the various identified water resources the following can be concluded:
3. Non-viable resources
- Groundwater is not considered a promising source for irrigation water in the Felicity area. The
consultants will not consider groundwater in the mix, for now.
4. Inside the Felicity project area
- Ponds are already constructed on many plots, and are easily and cheaply constructed. The
concept is clear, though the farmers feel that the capacity is too small and the ponds take too
much arable land, especially when they are dry. The study suggests that ponds do have an
essential function in safeguarding irrigation in the Felicity Area, both during the rainy season to
bridge dry spells and as buffers to store and distribute irrigation water during the dry season. The
criticism of the farmers can be countered if a single pond is used for one plot and if the ponds are
27
Groundwater has a total score of 0 because it can be neglected. Water availability cannot be negative. 28
It is uncertain if the Mamoral dam will be built; it will certainly not be built within the near future 29
4 ++++ can be awarded as this criterion has twice the weight 30
O&M costs will directly influence user fees, if the O&M is to be paid by the beneficiaries. This is the usual approach in small-scale irrigation projects. 31
The primary system is the infrastructure that takes the water to the Felicity area. The secondary system distributes it to individual farmers or groups of farmers, while the tertiary system is where the farmer or group of farmers apply the water to the crops, including the on-field infrastructure. 32
Using the Caparo River means installing large pumps and the requisite electrical system; this is more expensive than initially expected. 33
Total: simply add all +, - and o, valued at 1, -1 and 0.
76
replenished from an outside source during the dry season. The land loss, at about 5%, is
acceptable considering the advantages of irrigation and increased water security. The total
capacity of the ponds is 1 Mm3 for the entire Felicity area. The consultants recommend using the
ponds (individual or for groups of plots), and construction of ponds for each of the plots that are
to be irrigated. This is in line with the policy of the Ministry of Food Production34
.
- Directly linked to the above it follows that an infrastructure needs to be constructed that can
replenish the ponds. A network of rigid (preferably buried) pipes, a network of irrigation channels,
or a combination of the two will be required, to carry the water from the intake location to the
ponds. This system can be operated on a rotational, non continuous basis, given the fact that the
ponds hold a buffer of at least 6 weeks of irrigation water. The consultants prefer a system of
(buried) pipes, especially since this proves to be the preferred method used in other areas
(Orange Grove 2-acre plot area).
- A method to measure the amount of irrigation water used by an individual farmer is needed.
5. Outside the Felicity project area
When considering the above, possible sources of water to supply the ponds are to be identified.
Looking at the matrix of Table 14.2 there are two viable options, described below.
The Caparo River, but only after rainfall has created enough run-off to flush the accumulated
pollutants and dilute any that are being added to it. For this four things are needed:
1. A weir or weirs are to be constructed in the Caparo River, and possibly basins need to be
constructed to allow pumping. Such basins hold relatively small amounts of water;
2. Large ponds to fill quickly, along the river (buffer of peak flow);
3. A number of large capacity pumps to quickly fill the large ponds when a suitable discharge peak
occurs. The pumps have to be big because the suitable discharge peaks last only a few days at
maximum.
4. This needs a knowledgeable and adequate management, to decide when to operate the pumps.
The operator may get a warning based on rainfall upstream, from one of the rainfall stations in or
near the head of the basin, or through the meteorological services division. An operations
procedure cannot be given as this depends on the actual irrigation water requirement, which will
be different based on actual rainfall and water use.
The drawbacks of using the Caparo River as resource are twofold:
3. The cost of the pumps and the complexity of operation;
4. The residual level of pollution, and the unreliable, irregular and intermittent flow.
A clear advantage is that all needed infrastructure can be built within the project boundaries, so it
is easily controlled and managed by a farmers representative body (Water User Group?).
Building the infrastructure is relatively simple and straightforward, but expensive.
The Mamoral reservoir and the Ravine Sable Sand Pits. Both sources would have the same
advantages and disadvantages, and can and even should be operated as one system. At this
moment it is not certain that the Mamoral dam will be built. The Ravine Sable Sand Pits appear to
have enough water for both the Felicity irrigation requirement as well as to cover the WASA demand
for domestic water supply (Figure 14.3).
34
In discussions during the last days of the project it emerged that the on-farm ponds may hold less water and take up more land. An alternative with smaller ponds has been investigated; see Design Annex.
77
For the sake of this discussion it is assumed that water can be made available from the Ravine Sable
Sand Pits. If the Mamoral Dam is built a means to convey the water to the Sand Pits needs to be
decided upon (pipe, or by releasing it in the Caparo River bed). Also, an inlet and cross dam needs to
be constructed in the Caparo River next to the sand pits divert the river water in a controlled manner
into the sand pits. It is assumed that such works will be constructed as a part of the flood control and
mitigation measures currently being studied by the Caparo River Basin project; they will be
considered only in a qualitative manner by the Felicity irrigation project.
While the active storage of the Ravine Sable Sand Pits is not sufficient to cover all the requirements
of the Felicity area, it will also collect runoff during rain in the dry season, increasing the total water
yield. In combination with optimal use of the ponds in the Felicity area the water from the Ravine
Sable Sand Pits is expected to cover the irrigation water requirements for the Felicity area (NIDCO,
2013; Figure 14.3).
A method to convey the water from the sand pits to the Felicity irrigation intake is needed. There are
two options:
3. Use the Caparo River as conduit by pumping the water from the sand pit back into the river. This
appears to be a very elegant solution: the entire infrastructure to utilise the water of the Caparo
River during the rainy season is the same as for the dry season. However, the cost of pumping
for this option is significant.
4. Build a pipeline, estimated length up to 10km, and use the Ravine Sable Sand Pits as buffer.
Using the Caparo River as conduit:
Advantages
- The entire infrastructure at the Felicity area can be used both in the dry and rainy season,
although the buffer (intake basins) capacity may have to be increased to avoid loss of water
through spillage35
and a number of large pumps are needed;
- The required ecological flow will add to the irrigation water volume available at the intakes at the
Felicity area.
- Implementation and construction time are relatively short (easily within one dry season).
Disadvantages:
- Cost for pumps, electricity grid, transformers.
- Losses, mostly from legal and illegal abstraction from the Caparo River between the sand pits
and the Felicity inlet, are expected to be higher than for a pipeline
- The water will collect polluted effluent, decreasing the water quality on its way to the Felicity
Area.
- Operation of the pump at the RSSP has to be coordinated with the pumping at the Felicity
intake(s), taking into consideration the travel time through the river
- Leakage beyond the Felicity inlets may occur if not all released water is pumped29
. However, a
limited ‘ecological flow’ is required anyway.
Building a pipeline as conduit:
Advantages
- Losses are expected to be low.
- Water quality will not be decreased by lateral inflows
35
If the closed-loop system is implemented this water can then be re-used, making spillage less problematic
78
- The system will deliver water at pressure to the Felicity area, facilitating easy distribution in the
secondary system. It will be possible to construct a fully pressurised system delivering the water
to the ponds, with relatively small pumps as the system can convey water 24/7 (with ‘smart’
operation and management);
- This system could possibly be implemented without the ponds, though management of a system
without ponds is very complex and the buffer will be cancelled, significantly increasing the
required dry season flow from the RSSP reservoir. Preliminary calculations (NIDCO, 2013) show
that this is not feasible. Management of this system and both investment and O&M costs will be
higher, due to irregular demand. This approach is deemed not viable by the consultants.
Disadvantages:
- Costs are significant, but may in the end be lower than using the Caparo River bed as conduit,
due to the huge difference in required pump capacity. Also, pumps need to be replaced while the
pipeline is probably good for more than 50 years.
- Implementation and construction will be time-consuming. A detailed survey of the right of way is
required, followed by a detailed design. Access to land and the actual right of way has to be
purchased where this is not government owned. A project like this will require tendering
procedures that are much more demanding and time-consuming than for the construction of a
simple pump unit.
79
15. SELECTED OPTION
15.1 Selected water resource option
The consultants concluded that there are two viable options to provide irrigation water to the Felicity
Pilot area. Both include the individual ponds and a system to replenish these ponds.
Option 1: Source water from the Ravine Sable Sand Pits, possibly in combination with the Mamoral
Dam Reservoir, conveyed to the Felicity Pilot Area using the Caparo River. This will include intake
works and a large number of big pumps on the Caparo River within the project area. During the rainy
season the natural flow of the Caparo River can be utilized to replenish the ponds. During the dry
season water can be released (pumped) from the Ravine Sable Sand Pits into the Caparo River bed.
Option 2: Source water from the Ravine Sable Sand Pits, possibly in combination with the Mamoral
Dam Reservoir, conveyed to the Felicity Pilot Area using a pipeline. This will mean that the intake
works in the Caparo River may not be needed, and water is available at the intake to be distributed to
the ponds under pressure. This option has the advantage of offering 24/7 supply, resulting in relatively
small flow rates (maximum 170-175 l/s) which can be handled with small pumps and a pipe diameter
of about 50 cm (20 inch).
Closed loop system: Adding the closed loop re-use system to either of the above options will reduce
the required amount of ‘fresh’ irrigation water. The effects of applying this interesting concept will have
to be modelled; a rough estimate can probably and possibly be done quickly. Introduction of the
closed loop system has a clear and negative effect on leaching requirements. It is recommended to
implement this only after an additional study into the effects on the soil salinity and the economics.
See also Chapter 16 on salinity and risks of salinisation.
The consultants suggest that Option 1 and Option 2 are considered as Phase 1 and Phase 2. It is
recommended to start with Option 1 for a limited number of plots (100-120) in the Felicity area, and
then start the preparations for building the pipeline. The process of detailed survey, detailed design,
tendering, possibly expropriation and compensation (along the right of way), construction and delivery
can then take place without delaying the introduction in the Felicity Area.
15.2 Recommendations with selected water resource
- Ponds need to be constructed for each plot, as a buffer and to bridge protracted dry spells during
the rainy season. An infrastructure to replenish the ponds is required. The ponds need to be
refilled from an external irrigation water source about once six weeks during the dry season, once
every two months during the rainy season. A fee could be collected for the filling, to be organised
through a communal organisation / WUA.
- The water volume available for irrigation or other purposes in the Mamoral Reservoir – Ravine
Sable Sand Pits is not a straightforward function of the active storage. During the dry season
there is still rainfall and thus replenishment of both the reservoir and/or the sand pits. On the other
hand there are losses due to direct open surface evaporation. The Caparo River Basin project
has made preliminary model estimates which indicate that the requirements of both the Felicity
irrigation requirements and WASA for domestic use can (just) be met. The final results of such
modelling should be evaluated and used to adjust (if necessary) the results of the Felicity area
irrigation design.
- The amount of water to be abstracted for the Felicity irrigation area has to be clearly claimed in a
water abstraction license / water abstraction licenses, to prevent later developments upstream
from endangering irrigation in the Felicity area.
- It is recommended to develop and follow a very clear policy which outlines the allocation of water
under circumstances of water scarcity. While under almost all circumstances the provision of
drinking water will always take precedence over agricultural water use, the domestic supply sector
80
should shoulder a reasonable part of the effort to save water, by reducing water use (and
wastage) and possibly by introducing rationing. Cutting off the entire supply to agriculture from a
shared water supply should only take place under exceptional circumstances. Management of
such shared resources should be aimed at optimising the dual use of the resource.
- At this moment there are no treatment plants in the area that can deliver treated wastewater to
the Felicity irrigation area. If and when a large treatment plant will be build, e.g. in Chaguanas
Town, which is just upstream from the project area, a connection (pipe or otherwise) to convey
this water to the Felicity irrigation area should be considered.
15.3 Considerations with selected water resource
- Ponds take up about 5% of the plots (400 m2 out of 8000 m
2)36
. The land lost is thus not really
excessive. They hold the equivalent of up to 200 mm irrigation, or up to 6 weeks of irrigation water
requirement in the dry season, and enough to bridge a dry spell in the rainy season. If applied to
only one plot and if the water is not wasted, but applied correctly, the ponds are actually very
effective. Disadvantage: the farmers have to use their own (or communally owned) pump.
Advantage: they do not depend totally on an outside source that can be cut by accident, or on
purpose (water allocated for domestic water use). And the farmers maintain and pay for fuel for
their own pump, increasing ‘ownership’ and responsibility and minimising the dependence on the
GoRTT.
- Of the identified external water sources only the Ravine Sable Sand Pits and possibly the
Mamoral Reservoir can supply the required water during the dry season. It is not certain if the
Mamoral reservoir will be built, and the competition for the water will be strong. The total available
water availability for agriculture in the Caparo Basin is expected to just cover the requirements for
Felicity. Implementation of further irrigation schemes in the basin will need additional buffering. In
this case the Large Buffer Ponds (reserved areas in Felicity) need to be constructed and filled
during the rainy season, and Large Buffer Ponds are also needed in the new irrigated area.
Alternatively another cropping pattern can be adopted, for instance by only irrigating half of each
2-acre plot during the dry season.
- Irrigation during the rainy season is also needed, and this need is expected to increase due to
climate change.
- Construction of larger ponds has the clear advantage that the system to replenish the ponds can
be much simpler. The disadvantage is that individual farmers cannot control or see exactly who
uses how much of the water, possibly leading to disputes and water wastage (‘tragedy of the
commons’). Unless a very clear mechanism to control the use of pond water can be devised, set
up and enforced (metering the outflow?) it is recommended to build ponds on all individual plots,
unless adjacent plots are farmed by one farmer or cooperative
15.4 Potential Environmental Impacts and Mitigation Measures
The environmental impacts and mitigation measures concerning the construction & operation of the
works related to the preferred options are presented in Table 15.1. The potential environmental
impacts and mitigation measures related to the irrigation practices themselves in the Felicity Project
Area have been presented and explained in Chapter 12.
36
Discussions in the last days of the project revealed that the land taken by the ponds may be up to 9% of the plots. The option of smaller plots has been studied and adopted for Phase 1 (see Design Annex) at the Design Wrap Up meeting on Monday 9 September 2013.
81
Table 15.1: Potential impacts & mitigation measures related to preferred options for source water and
conveyance
Preferred options for source water and conveyance
Potential Negative Impacts
Mitigation Measures
Potential Positive Impacts
source: Ravine Sable Sand Pits, conveyance by Caparo River
increased erosion of embankments of the Caparo River
stabilisation of embankments, proper environmental management and monitoring
improved quality of river
water downstream by
discharging water from
sand pits in Caparo River,
better control on required
ecological flow source: Ravine Sable Sand Pits, conveyance by pipeline
temporary impact of activities during the construction phase, spilling of materials (cement, diesel, oil), soil compaction
proper environmental management and monitoring
82
16. DESIGN AND FEASIBILITY STUDY.
16.1 Introduction
This chapter deals mainly with the civil engineering design of the Felicity irrigation scheme, for the
location see Figure 16.1. In addition the input for the feasibility study is prepared.
The present water supply and irrigation and a summary of the future water supply options and
constraints are presented (see also Chapter 13, 14 and 15) and the technical consequences of the
choices are indicated.
Chapter 16.4, Water distribution – organisation and management will deal with the water balance (see
also Chapter 13) with the emphasis on drainage, salinity, leaching requirement. Also water
management in the field in relation to design is discussed: filling times, rotation schedules and
capacities of ponds, operating times, and guidelines on capacities and energy use of pumps and on
diameters and pressures in pipes and appurtenant installations.
Note: As decisions on design boundary conditions and options were taken up to the last days of the project, and
some relevant information also became available only during the last days, these have been used in the ‘final’
design as detailed in the Design Annex. At relevant locations in the text of this chapter footnotes have been
added.
Figure 16.1: Location of the Felicity project area
16.2 Water supply options - technical details
Typical for irrigation is that water (rainfall, river flow) is at wrong location at the wrong time. It involves
(on-field) storage of water and/or transport of a source (river, reservoir) to an agricultural area.
In the case of Felicity it means that, for the dry season, the nearby Caparo River is now used for
irrigation purposes. A major issue is that most of that water, of reasonable to good quality, passes
through the river in the wet season, whereas in the dry season the flow becomes very peaky, and the
base flow (actually non-existent) is of very low quality. This water has to be captured and stored if it is
to be used efficiently.
On-farm ponds
The original plan for the 2-acre plots assumes storage in the field: each farm plot has a 1600 m3
pond37
to collect (rain) water. When filled it is good for 200 mm irrigation, including field losses, or
about 6 weeks in the dry season. Storage of direct rainfall in the ponds is not enough to fill the ponds,
let alone carry the crop through the dry season. The Caparo River is the next source of water to fill the
37
Possibly smaller, based on discussions during the last days of the project. See Design Annex.
83
ponds. The ponds allow a scheme wide storage of about 1M m3 when full, well short of the
approximately 3.5M m3 required for the dry season. Three full (re-)fillings would be required to secure
a full crop; this is not possible without additional measures (Chapter 13).
Large buffer ponds
Inter-seasonal storage is needed to provide the required water. Large buffer ponds (LBPs) were
envisaged to store the river water during the wet season and to capture the occasional peak flow in
the dry season, and release the water to the OPs as required. Approximately 68 acres were reserved
for this purpose in the design for Felicity, yielding a storage capacity of 1.1M m3, also with 4.5 m live
storage depth38
. With large pumps the peak flows of the Caparo River in the dry season could be
effectively stored, and a fully irrigated crop can possibly be secured. However, the peaky behaviour of
the flows allows (very) short pump opportunity times (POT), leading to high capacity pumps and pipes
between the river and he LBPs. More pumping intake points and higher weirs at the pump intakes,
thus creating a buffer in the river, may extend the POT, but the effect of this measure is limited.
Ravine Sable Sand Pits
An adequate inter-seasonal buffer is available when making use of the Ravines Sable Sand Pits
(RSSP) (see Chapter 13). Water will be released from the RSSP either through a pipe (a relatively
constant flow) straight into the distribution network of the Felicity irrigation scheme, or through the
Caparo river itself (in short bursts as to limit inefficiencies and opportunity of tampering with the flow)
into LBPs as to minimize the capacity requirement of the secondary distribution network (pumps and
pipes).
The latest (preliminary) modelling results show that in principle all competing claims can be met, with
difficulty probably also for the design situation in 2050 (Chapter 14, 1:4 year).
Using the combination of the Caparo River with LBPs would have the advantage that it can be
implemented quickly, although the water supply from the RSSP would at least partly depend on
(large) pumps. A serious drawback is that for filling the LBPs (1.1M m3) it requires large pumps (and
piping), both at the RSSP and at the Felicity intake. Even if the POT is increased, the pumps required
to fill the LBPs would have a high capacity and would be seriously underused (idle most of the time).
This means that the pipe option with a constant small flow is by far preferred from a technical point of
view. However, the construction of the pipe may prove to be a challenge and it may take several
years before such a pipe will be built, depriving the Felicity irrigation scheme of irrigation during that
time.
It is therefore proposed to adopt a phased strategy: start with a small section of the Felicity scheme at
the head of the project area. For the first 2-3 years 4 LBPs could be constructed at the head of the
distribution system while the pipe project is further developed and then constructed in close
coordination with WASA. The pumps used to take the water from the Caparo River at the temporary
LBPs could then be moved to the RSSP. Some LBPs could also be maintained to ease water
management bottlenecks in the Felicity irrigation scheme. They can also be used and even extended
to support the development of nearby schemes, such as Edinburgh irrigation scheme, or even as fish
ponds with an emergency water supply function. As the reservation for LBPs is still on the map, a full
development of the LBPs, partly to support irrigation in other regions, remains possible. The extension
of the POT would have to be further investigated. A lot of flexibility is created with this phased
approach.
16.3 Pumps, pipes and ponds
16.3.1 Lay-out and nomenclature
38
The design is adjusted based on newer information – see the Design Annex.
84
The layout of the system is determined by the present layout of Felicity irrigation scheme, and follows
to some extent the standard layouts of other developments within the MoFP39
. The most striking
elements are the main, primary supply system and the secondary distribution system. Basically the
secondary distribution system is the same, regardless of the selected primary supply system: all flows
and ponds, pipes and valves will have the same capacities and dimensions.
Large Buffer Ponds are located on the reserved areas and named starting from upstream going
downstream on the Caparo River, with L indicating the left bank and R the right bank. LL are ponds
on the Chandernagore River (Figure 16.2, Figure 16.3).
Figure 16.2: Large Buffer Ponds on Caparo River, map
Figure 16.3: Large Buffer Ponds on Chandernagore River, map
39
The consultants have studied design drawings of the Orange Grove 2-acre area
85
Table 16.1: Preliminary Make up of Secondary Units.
Table 16.2: Capacity LBP and pumps
Area in plot units (2 acre); V in m3, Qfill in m
3/s)
Table 16.3: Preliminary set-up of supply and distribution systems40
Primary supply
through pipeline
Primary supply
through river
River regime first,
pipe regime later.
Main supply system
Ravine Sable Sand Pits (RSSP) Managed for flood attenuation, agricultural and domestic supply
Flood attenuation Infrastructure for gravity inflow and outflow, see study Royal HaskoningDHV
(NIDCO, 2013b)
40
Following discussions during the last days of the project the design could be more focused as a number of choices have been made. For these details see the Design Annex.
Preliminary make
up secondary units
Nr. of plots
in Unit
Secondary
size (ha)
1L 274 302 29 22.4
1R 126 193 68 52.5
2L 249 273 25 19.3
2R 1 125 125 96.4
3L 194 248 55 42.4
3LL 273 353 81 62.5
3R 1 77 77 59.4
4L 78 161 84 64.8
4LL 162 272 111 85.6
Total 655 505.3
No. of plot (first -
last in SU)
Preliminary
make up
secondary AreaLBP V LBP Qfill
1L 3.0 97,440 0.23
1R 3.5 113,680 0.26
2L 2.0 64,960 0.15
2R 4.5 146,160 0.34
3L 3.0 97,440 0.23
3LL 2.5 81,200 0.19
3R 3.0 97,440 0.23
4L 6.0 194,880 0.45
4LL 5.0 162,400 0.38
Total 32.5 1,055,600 2.44
Tfill (days) 5
86
Primary supply
through pipeline
Primary supply
through river
River regime first,
pipe regime later.
Pump(s) (for agriculture) Relatively small flow of
212 l/s (=175 + 20%).
Δh in RSSP is variable:
WLhi – WLlo < 15m
(see Figure 16.4 and
Figure 16.5)
Large pumps to
simulate peaky
character of Caparo
River in dry season.
Δh <15 m. Large flows
be better not pumped
when Δh > 7.5 m; this
has impacts for
availability water in dry
season, to be resolved.
Large pumps to
simulate peaky
character in dry season
(for 100 – 250 ha first)
Δh <15 m. Large flows
be better not pumped
when Δh < 7.5 m
Relatively small flow of
212 l/s (=175 + 20%)
WLhi – WLlo < 15m with
sometimes high energy
requirements.
Pipe line 212 l/s (=175 + 20%) NA 212 l/s (=175 + 20%)
River41
No works Limited re-sectioning No works
Pump intakes at Felicity NA 7-10 3, possibly to be
removed later
Peak flow pumps (capture
peaks from river)
NA If POT can be extended
to 5 days, between 0.1
and 0.5 m3/s. If POT
only 1.5 days: between
0.35 and 1.75 m3/s.
Only for first SUs LBP
and pumps to be
installed: 3 pumps with
capacity below 0.3 m3/s
LBP (for peak storage) NA App. 24 ha has been
reserved. With 4.5 m
storage: 1.1 M m3 live
storage, could be filled
several times per year
Only a limited area,
possibly 3-4 ha) at the
head of the Felicity
irrigation scheme to be
established, possibly
later rendered defunct
Buffer pumps (to pump water
from the LBP into the secondary
distribution system)
NA 7- 10 pumps with
capacities
commensurate with SU
requirements
3 pumps with
capacities
commensurate with
relevant SU
requirements
Distribution system
Pipe lines (SU) Σ QSU = 200 l/s (167 + 20%).
Valves One on each SU (up to 125 ha); approximately 10 secondary pipelines. To
be securly built in manholes where they can be locked.
Pipe lines (TU) Σ QTU = 187 l/s (156 + 20%).
Valves One on each TU (up to 18 ha); approximately 35 tertiary pipelines. To be
securly built in manholes where they can be locked.
41
Inlet works at the RSSP to be constructed following the Caparo River Basin Study recommendations for flood mitigation and water supply – not considered here.
87
Primary supply
through pipeline
Primary supply
through river
River regime first,
pipe regime later.
On Farm Ponds Total V = 655 @ 1600 – 1800 = max 1.2 Mm3.
Standard pond filling is 2000 mm (800 m3)/turn. Assume a filling time of 12
hrs: 800/12 = 67 m3/hr = 18.5 l/s; longer filling times are possible: 48 hrs
would require 4.6 l/s. Larger fillings can be allowed but require more time
(and more supervision: spilling should be prevented).
Valves One on each pond (except where plots/ponds are consolidated, possibly
fewer valves can be installed). Max 655 units, possibly as few as 100. These
valves are stepwise adjustable (seeXX) and lockable, yet accessible for O&M
staff.
Private pumps and on-field
irrigation systems
Under farmers control and responsibility.
Miscellaneous items
Electricity for pumps
Main system It is assumed that for the electrification for the pumps at RSSP a co-
operation with WASA can be arranged. High voltage.
Alternatively diesel pumps can also be considered42
.
Secondary system For possibly a booster
pump in network, a
(high voltage) electricity
connection may be
necessary (to be
investigated)
For numerous buffer
pumps a (high voltage)
electricity network to be
installed.
Dependent on
development path:
temporarily (high
voltage) network, or a
permanent electricity
network, for expansion
of irrigation to other
schemes (to be
investigated).
On-farm ponds For hundreds of small pumps, low voltage (110 – 230 V) an electricity
distribution network needs to be built.
Water meters On a number of strategic locations (e.g. at each tertiary pipeline) water
meters to be placed.
In Figure 16.4 and Figure 16.5 the simulated water levels for the RSSP over a 15 year period are
presented under the combined purposes of flood attenuation, domestic water abstraction (3.3M m3)
and irrigation for the Felicity irrigation scheme (4M to 6M m3). Water level is shown to vary from 30 m
+MSL (above the low water level of the Caparo River) to 15 m +MSL43
below the low water level of
the Caparo River. This posed a serious challenge for pumping for irrigation: the cost of pumping goes
up at such lift heights.
42
Diesel pumps at relatively high capacity are available with the Ministry; see also the Design Annex. 43 Note: the water level is actually in mm above MSL – the maximum level is at 30 m above MSL. Source:
Caparo River Basin Study, Royal HaskoningDHV – preliminary findings. As the source is not available the y-axis
legend cannot be corrected.
88
Figure 16.4: Simulation water level at Ravine Sable Sand Pits - 2013
Note: the water level is actually in mm above MSL – the maximum level is at 30 m above MSL. Source: Caparo
River Basin Study, Royal HaskoningDHV – preliminary findings.
Figure 16.5: Simulation water level at Ravine Sable Sand Pits - 2050
Note: the water level is actually in mm above MSL – the maximum level is at 30 m above MSL. Source: Caparo
River Basin Study, Royal HaskoningDHV – preliminary findings.
In Table 16.3 a maximum primary conveyance (design) capacity of 212 l/s is proposed; in Figure 16.4
and Figure 16.5 lower flows (maximum of 165 l/s) have been used in the simulation44
. In 3 out of 4
years more water is available. The proposed pumps can accommodate larger flows, furthermore there
is water over and above the maximum filling level of RSSP (for flood attenuation), which was not
regarded in the simulation. These flows can be accommodated by the spare capacity in the pipeline
and the ponds (LBP’s), and can be used to further increase the water security in the Felicity area.
44
Reference: email exchange with acting team leader of Caparo River Basin Project
89
16.4 Water distribution – organisation and management
16.4.1 General
Irrigation systems should be designed in such a way as to make the organisation and management as
well as the operation and maintenance as simple and as straightforward as possible. A very good
term for this is ‘robustness’. A robust system can work under many different circumstances and will
not be sensitive to mistakes in operation. Robustness of a system is a function of both the technical
design and the way it is operated – and these two aspects need to be considered in parallel.
Other considerations are:
1. where does the responsibility of the irrigation organisation stop and the responsibility of the
farmer start
2. how to avoid losses due to characteristics of the distribution network
3. what happens when a part of the system is out of order for some reason
4. how to avoid water wastage
By preserving the concept of on-farm ponds the first three considerations are clearly addressed; the
ponds are the responsibility of the farmer, filling the ponds is relatively straightforward and if somehow
the system to replenish the ponds fails for several days or even a few weeks the ponds hold enough
water to bridge this period.
For consideration 4 a clear way of measuring and then pricing water is needed. Filling the ponds with
set discharges during set times means that the delivered volume of water for each farmer is known.
While the price for the normal amount of irrigation water can be part of the lease payment, any excess
water use should be priced at a level that will deter wastage.
16.4.2 Irrigation
Scheduling – filling of on-farm ponds
Irrigation scheduling usually takes place at the field (soil) level, by shifting the flow of irrigation from
one farmer to the next. In the Felicity irrigation scheme the scheduling point is the on-farm pond. The
consultants propose to install filling pipes to the ponds, equipped with valves which allow for set
volumes of fill: 2 meter water level (800 m3), 1 meter (400 m
3) or 0.5 meter (200 m
3). The setting of
the valves should be done by someone appointed as manager of the secondary distribution system.
Every day at a set time he/she sets the valves of a specific number of ponds to the levels that he/she
determines, based on the conditions in the field. In this manner all ponds are filled on a rotation basis.
For setting of valve, time and flow see Table 16.4. Depending on the setting of the valves more or
fewer ponds can be serviced. The calculated flow at the tertiary level, to fill the pond, is 150 l/s. This
translates into 32.5 meter over 24 hours, expressed in meters pond level45
.
Example: If the valves are set every 24 hour, on a certain day all ponds will receive 2 meter, 16 ponds
can be filled by opening 16 valves at the 2 meter setting (plus one at the 0.5 m setting). Alternatively,
32 ponds can be filled with 1 m (plus one at 0.5 m). And of course any combination is possible as long
as the total adds up to 32.5 meter over 24 hours. The manager has to have a good idea on the level
of the ponds in different areas of the scheme, and should prepare a schedule for all valve settings for
that day.
Details for the pond filling have to be determined once the design is final.
If operation is difficult on a certain day the valves can be set for 48 hours, but at half the level setting.
45
For smaller ponds different flows and times are needed.
90
Table 16.4: Filling of On-Farm Ponds
0.5 m 1.0 m 2.0 m Depth (m) Volume (m3)
48 h
4.6 0.5 200
24 h
4.6 9.3 1.0 400
12 h 4.6 9.3 18.5 2.0 800
For equal distribution of the water the manager should open valves in at least two different branch
pipes, and preferably more. If all water demand is concentrated along one branch the pressure
distribution among the valves will vary significantly more resulting in uneven distribution of water.
Should a farmer need water before his/her turn a request can be filed with the manager and his/her
pond can be scheduled with the next shift. The manager should ensure that the water is evenly
distributed, as the total amount for Felicity is limited. Giving too much water to too many farmers early
in the dry season may mean that some farmers may not get enough later in the dry season, when
ponds are drawn down too fast.
Having a manager to set the valves has additional advantages. The manager can record the water
levels in the ponds (staff gauges are required) and the electricity consumption of the farmer’s
irrigation pump. The manager can also read the water meters that are installed at selected valves, for
calibration and cross-checking. The consultants recommend the use of a smartphone or tablet to
enter the data on the spot and to take photographs for later verification, especially in order to resolve
disputes. All valves, electricity meters and staff gauges need to be clearly labelled with the plot
number.
Large Buffer Ponds
A limited number of Large Buffer Ponds may have to be incorporated into the final irrigation system
for Felicity, to facilitate overflow and possibly to buffer water made available over and above the
normal allowance for Felicity – this may happen during peak flows and after the RSSP has buffered a
flood peak. Extra flow may also be routed directly into the system, by increasing the number of ponds
/ total daily ‘pond depth’ to be distributed. However, it is recommended to use LBPs to even out large
imbalances in water availability, e.g. if enough water is available during the rainy season it can be
buffered in the LBPs and then applied to help bridge an unusually dry period of the dry season.
Operation of the LBPs adds a layer of complexity to the task of the irrigation manager. An operation
procedure or manual is needed to facilitate the decision to use the LBPs, and how much of the stored
buffer to add to the system. The infrastructure to use the LBPs needs to be included in the design
(pumps to pump the water from the LBP into the secondary distribution system, overflow valve and fill
valve to fill the LBP when excess water is available at the RSSP.
16.4.3 Drainage: (ground) water and salinity control
The main objective of drainage is to evacuate excess water from the land to ensure maximum
production on the field:
prevention of waterlogging: puddles on the field (hamper farm operations, may also cause
damage to crops) and water levels that are too high (hamper optimum crop production
because roots are not well aerated);
prevention of (secondary) salinisation, which is the addition of salt to the field/system salt
balance because of capillary rise from excessively high ground water levels, after (over)
irrigation with (almost always) saline water.
91
Drainage has two flows to be considered: surface run-off, particularly under heavy rain showers, on
heavy soils, like in Felicity, and sub-surface drainage, in case of high ground water levels,
exacerbated by (over-)irrigation and, in (semi-)arid areas, with the threat of salinisation. Generally
surface run-off needs to be evacuated rapidly, as many crops cannot stand wet feet. With the help of
a drainage module the drainage system can be designed. In irrigated areas with heavy rain showers
and on heavy soils the drainage module may be quite high (well in excess of 2 l/s/ha). For the Felicity
area the drainage module is yet to be determined.
The other flow, sub-surface drainage, aims more at ground water level control, and indirectly at
salinity control. Drain spacing is an important parameter in sub-surface drainage. In Felicity the
present drain distance is about 250 m. For heavy soils such as in Felicity this may be on the high
side. This needs to be investigated.
Present status
Little is known about the actual drainage status of the Felicity irrigation scheme. However, there does
not seem to be a water logging problem, but under more vulnerable crops with increased irrigation
this might just become an issue. There do not seem to be floods that damage the crops but changed
agricultural practices with more vulnerable crops may change that. Salinity is a problem that occurs
mainly in (semi-) arid climates (which Trinidad is not), especially when the land is irrigated (which the
Felicity irrigation scheme is not yet). In the Felicity irrigation scheme it appears that there is a
drainage surplus (in the wet season and over the year on average), though the salinity found during
testing seems to indicate salt accumulated in the deeper subsoil. Further investigations are required.
Increase in ground water level
In irrigation schemes there is almost always the risk of rising ground water levels; only in those cases
where the drainage basis remains low and a new equilibrium can be formed with a ground water level
well below the root zone, one could consider to ignore drainage. Considering the proximity of swamps
downstream and the structure of the soil (relatively heavy clay) high ground water levels are a
concern.
Salinity in the future
Salinisation is a problem that occurs mainly in (semi-) arid climates, especially when the land is
irrigated. Even without (hazardously) increased ground water levels salinisation remains a threat.
Irrigation water always carries salts and if there is no proper mechanism of evacuation of these salts
through drainage water (percolation and possibly additional leaching water) these salts will build up in
the soil. If low quality water is used (re-use of drainage water – closed loop system) and/or if under-
irrigation is conducted, salinity problems may occur.
For a salt balance in equilibrium there must always be a net flux out of the root zone, more importantly
so if low quality water is used for irrigation. Over the year(s) there must be equilibrium, but dynamic
salt management, with varying levels of soil (water) salinity over the seasons, or even over the years,
is possible. One could think of leaching mainly in the rainy season, or of some form of “rotational”
leaching over a number of years.
In the Felicity irrigation scheme there appears to be a drainage surplus, and only in the dry season
there might be a risk of temporary salinity. This depends on factors such as the fraction of surface
run-off, actual infiltration (effective rainfall), and crop evapotranspiration. The very long time of
sugarcane cultivation may have caused an accumulation of salt in the deeper subsoil. This needs to
be investigated in much more detail.
In the long term conditions may change and salinity may become a concern; at the same time in 40
years from now desalination of (irrigation) water will have become cheaper, crops have been
developed (or found) to withstand higher salinity levels, greenhouses have replaced open field
agriculture, etc., and many of the problems we face now may have become manageable.
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In Annex 11 the physical relationships between water quality, water quantity, soil salinity and leaching
requirement will be quantified and boundary values will be presented: at this moment there are,
however, insufficient data on soil texture and water quality (salinity) available and it will remain a
theoretical exercise.
Use of water from blocked drains
At the moment some farmers tend to (support the idea to) block drains in the dry season. This would
avoid the need for a pond in-field, land which the farmers would rather use for crops. There are three
topics that require consideration: water quality and water quantity, and hampered drainage.
- Water quality. Part of this water is not drainage water as such, but surface run-off: rain water (at
the end of the wet season) and possibly irrigation water. Even some sub-surface flow may be
captured, although this is bound to be minimal: the drain water level has (temporarily) become the
local drainage basis and there is little head left in the field to drive the flow: there is a risk of water
logging in the field. The water must be of reasonable quality, certainly at the beginning of the dry
season (=end of wet season). Over the season it may deteriorate, and can perhaps only be used
after mixing: however the salt concentration may be lowered, preventing local damage to a crop,
the salt load is not reduced and the salinisation (in the dry season) continues. The risks are (still)
low, and dynamic salt management might control this process.
- Water quantity. For the store to be effective the drain has to be “full” for as long as possible and
refills are necessary; in some locations drainage inflow from higher fields may help, but the extent
of such inflows is unsure. In all fields the side where the drain is located is the short side (60-70 m
long). The average drain has a width of reportedly 6-10 m (top width) with a depth of 2 m (in
heavy clay, 3 m will more likely) and side slopes of 1:1, hence the bed width is 4 m. This means
that the volume of a drain reach is 6*2*60 between 700 – 1000 m3 assuming water level equal to
field level (at the lowest point), an unwanted situation: certainly in the vicinity of the drain
waterlogging conditions will prevail. This volume has to be shared by two farmers: < 500 m3/drain
reach. Drains upstream are smaller than drainage down-stream, so upstream farmers would have
less storage than downstream farmers. In all it is not a very promising prospect.
- Hampered drainage. The principle of a drain is to evacuate water: blocking it is counterintuitive.
Yet water level control in drains is widely practised in delta areas around the world. The (short
term) full ponding of drains described here goes further than water level control. In the vicinity of
the drain water logging conditions may prevail for prolonged periods. Furthermore it is always
unclear when a blockade has to be installed (preferably before the last rain of the wet season) or
lifted (preferably before the occasional rain shower in/at the end of the dry season. As year round
cropping is practised, there will always be different conditions on different fields, different
interests, it will be difficult to please all the stakeholders. Some form of (dry season) water level
control is possible, but it requires well designed and organisation-sanctioned infrastructure and
should be incorporated in the O&M plans of the Felicity irrigation scheme.
Re-use of drainage water – closed loop system
Another water saving measure is he re-use of water from an otherwise unhampered drainage system.
This would amount to pumping the drainage water from the main drains, back to the head of the
system and mix it with fresh irrigation water: the salt concentration gets reduced, the salt load not. If
this would be implemented full time (also in the wet season) it might lead to salinisation even in the
tropical circumstances prevailing in Trinidad as the scheme (soil and ground water) would act as a
cul-de-sac (some ground water flow out of the area will reduce the salt load of the system, but too
slow). However, temporary (dry season) closed loop re-use seems possible from a water and salt
balance perspective, provided that in the wet season the salt balance is indeed restored to zero;
considering the current solid drainage surplus this should not be a problem. A consistent monitoring of
drainage water salinity and soil water salinity is essential: over the years the dry season will probably
93
get longer and the drainage surplus smaller: by 2050 the conditions in West – Central Trinidad may
be more like a semi-arid climate (with salinity risks) (Design Annex) than the present topical conditions
(without salinity risk). At some point in time the re-use of water may become risky and unwanted.
There are however technical complications. Drainage water is well below the ground level and has to
be pumped all the way back to the head of the system, this requires infrastructure and energy. The
most likely choice of the supply system is a pressurised pipe, and mixing the effluent will be
technically highly difficult, read expensive. It is probably a better idea to pass the water on to
Edinburgh and other downstream areas and re-use the water from drains with some water level
control (see above). Of course in the system pumping may also be allowed at checks structures. Also
here a good monitoring system is essential: the further downstream the water gets the more salts and
other particles it carries and, considering the climate shift, more critical water management conditions
may arise.
16.5 Design
16.5.1 System layout
From a hydraulic point of view it would best if the ponds that receive water (between 17 and 20 at a
time) would be evenly distributed over the pipe network. This would enable the designer to precisely
design a system, through varying dimensions of main, secondary and tertiary pipes, with minimal
pressure differences between extreme locations so that all ponds would receive 2 m (or any other
predefined filling, see 16.4.2) per filling, and at the same time minimise the outlay for infrastructure
and energy requirements. It is not wise to design with such a rigid condition; a more imbalanced water
distribution will most certainly occur. This means that higher pressures will be required in major parts
of the system than strictly necessary. To minimise variations pressure regulators will be incorporated
in the system, at yet to be determined places. In case LBPs are used the pressure in the (sub-
)systems can be better controlled. However, as argued earlier, the use of LBPs will introduce other
technical challenges.
The main supply (the primary system), the pipeline between RSSP and Felicity, will be placed parallel
to the Caparo River, probably on the right bank of the river (and/or in the Caparo River itself). The
pipe will have a capacity of 212 l/s, and will have a Ø 500 mm. The lower order secondary pipes will
carry flows of up to 100 l/s (less if agreeable) at Ø 300 mm. The filler / tertiary pipelines carry equal or
somewhat smaller flows, also at Ø 300 mm. The objective is to keep differential pressures within 0.5
atm. (5 m of water pressure) on a tertiary/filler pipeline, and within 1.0 atm on a secondary supply pipe
line.
Apart from pipes for irrigation there is also a need for drainage and for transport infrastructure. The
field/tertiary drains are already indicated on the pre design map, but the secondary and outfall drains
are not. Presumably the outfall is the Caparo River itself, and the secondary drains will be parallel to
the secondary roads in the system. Furthermore roads are planned in between the fields (tertiary
roads). These roads will be unsurfaced, with a minimum width of 4 m, with a shoulder of 0.5 m on
each side. The secondary roads will be (semi-)surfaced. Along the secondary roads the larger
secondary drains will be located.
16.5.2 Pipe system design
The supply and distribution system is completely based on pipes. Even in the event of the use of
LBPs, the distribution network will be based on pressurised pipes.
The flow formulae used in the design are explained in Annex 11. May it suffice to state that flow is
turbulent, and that the standard flow formulae are used.
The pipes in the system will be of PVC and will be buried. Some sections of the main supply pipeline
may be of other material, if so required: one could think of vulnerable crossings, uncovered sections
with valves and other special installations.
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For all the pumps in the supply (main) system, between one and three, and the distribution
(secondary) system, possible a booster pump and a number of (temporary) LBP pumps, the design
criteria and the actual design criterions will be explained.
Special infrastructure like pressure regulators, buffer tanks against water hammer, maintenance
valves and air valves will be specified.
All coefficients used in the design that control inflow and outflow losses, acceleration losses and
pressure losses over pipelines will be presented in Annex 11. Of one typical filler line (tertiary) and of
one distributor (secondary) a complete design will be presented.
16.6 Tender documents and contracts
These has to be discussed and based on workshops with the client.
16.7 Operation and maintenance
At this stage only guidelines for O&M can be prepared. For all infrastructure elements precise
operational rules will be devised (like for the valves described in 16.4.2).
For pumps and other electro-mechanical infrastructure the original manuals will be part of the O&M
documentation (stored at the respective pump houses and other work sites of the O&M engineering
staff). To ensure the project objectives are met specific instructions aimed at a correct distribution will
be part of the O&M manual. In principle a pressurised system like proposed in Felicity is “simple” to
operate: it is a modular flow system and whenever a valve is opened water comes out. However, it is
not a domestic water distribution system, it has a smaller over-capacity than such systems, and fewer
‘customers’, potentially concentrating demand in localised parts of the system. This means that some
central control is required to allow the large volumes required in an agricultural environment to arrive
at the destination without upsetting other parts of the system.
Specific care is required to ensure a trouble free operation of the system, water hammer being one of
the specific issues in a pressurised system.
A complete list of infrastructure elements will be part of Annex 11.
16.7.1 Cost of operation and maintenance
In the cost estimate of O&M the standard maintenance costs of equipment will be the basis of the
calculations. For electro-mechanical equipment generally 1% of the investment costs is used; for
concrete structures 0.5% of the investment cost. Earthworks require 1% of the investment cost.
However, in a pumped system there is also a high cost for energy; this will be estimated in Annex 11.
Careful operation can save a lot on energy (e.g. limiting pumping when the water levels in the RSSP
are low and pumping as much as possible when the Caparo River – RSSP are high. The differential
head between RSSP and the Felicity, approximately 20 m, reduces the energy bill considerably. The
use of the on-farm ponds has a huge positive impact on investments and pumping charges. The use
of (all) LBPs would have an equally large but negative impact on the O&M costs.
All in all the O&M costs will be considerable.
16.8 Recommendations related to design issues
Drainage requires additional investigations:
- with the help of rainfall data and water balance data at field level the drainage module for surface
drainage can be established;
- for sub-surface drainage the drain spacing (related to drain depth) deserves more attention. Soil
parameters like hydraulic conductivity, thickness of soil layers, and chemical make-up of the soil
(CEC, clay type) are important.
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16.9 Zoning
A visit to the Town and Country Planning Division of the Ministry of Planning and Sustainable
Development on August 20th brought light on the question whether zoning regulations are applicable
for irrigation projects. It appears that there are no specific regulations for zoning related to agricultural
projects, including irrigation development. For construction activities there is for example a margin to
be followed if a building is planned near a river side, but for agriculture there are in that respect no
regulations. However, there is controlling regulation, namely the Town and Country Planning Act
3501. This Act is being followed up by the Planning and Facilitation of Development Bill, which is now
in parliament. The Bill requires for irrigation developments (which normally includes infrastructure) a
plan to be submitted for verification to the Town and Country Planning Division. The Planning Division
will then react in writing whether there are objections or not to the plan and will refer to WRA, the
Drainage Division and the MFP. If the Felicity Irrigation (Pilot) Project is being duplicated to other
areas in the former sugar lands, then new sites need again verification by the Town and Country
Planning Division.
16.9.1 Economic Feasibility, Cost for Water, Farmers Involvement
16.9.2 Economic Feasibility
If the Irrigation Project, as proposed in current report, will be implemented, the Felicity Area with its
clayey soils – and with sufficient irrigation water in the dry season – could produce crops in all
seasons. It is highest on the wish-list of the farmers in the region: more water and sufficient water in
the dry season, so that the former sugar lands can produce crops the whole year round. For the
farmers is applicable the statement: ‘water availability is income security’.
In the scope of this compact Felicity Irrigation Project, with all its aspects from social to technical, it
would not be possible to present a full economic analysis of the introduction of irrigation practises in
the former Caroni sugar lands. However, there are several economical statements to bring forward,
as well as information on the usefulness of famers associations, and the introduction of cost for water.
Most vegetables for sale in Trinidad and Tobago are imported from Venezuela and the USA against
high prices and consequently vegetables in T&T in supermarkets and groceries are expensive. If the
Felicity Project Area would produce vegetables, grown on a sustainable basis – using non persistent
pesticides and only fertilisers if required – and selling for a price just lower than imported crops, then a
big agricultural market might develop. If the Felicity Irrigation Project is successful and being
duplicated to other former sugar lands, then a vast internal market for vegetables could develop. If the
production is large enough then even export might be an option.
Besides the famers themselves, also the Government of Trinidad and Tobago could assist in
developing the agricultural sector and obtaining the food security that is at present high on the political
agenda.
Possibilities of assistance from the government side are:
- Implementing fiscal and other incentives to allow farmers and the private sector to invest in
agriculture and food production in the region
- Develop infrastructure and logistics to support post-harvest handling, transportation, distribution
and marketing of food, based on the needs of a local market as well as of an international market
(export).
- Develop and implement measures to promote investment in the processing of agricultural
products, to add value and variety.
The benefits of implementing the Felicity Irrigation Project would be considerable: - Improved consumption and demand for local produce.
96
- Increased status of the agricultural sector.
- Increased food security.
- Decreased carbon footprint for imported foods.
- Increased environmental sustainability and possibly demand for organic foods.
- Increased economic diversification.
Funding of the initial investment for the Felicity Irrigation Project, as a pilot project, seems to be
secured. Recurring operation and maintenance (O&M) costs should be borne by the famers as
agricultural entrepreneurs.
16.9.3 Cost of Water
Sooner or later a price has to be paid for water, whether this is for drinking water, industrial water or
irrigation water. This is a worldwide phenomenon that is required to obtain sustainability. So far no
fees are paid for irrigation water by farmers in T&T. Initiating and promoting irrigated agriculture in
Trinidad and Tobago, it would not be wise to introduce payment for irrigation water at present. Still, in
the future a strategy has to be developed to introduce payment for irrigation water in T&T. The
willingness to pay by famers in the Project Area was brought forward during the rapid appraisal
session (chapter 7). The outcome was that the famers are prepared to pay for irrigation water, if first
there would be proof of a proper functioning irrigation system and increased income as a result of the
irrigation system.
The question then is how cost for water could be organised. A flat rate is an option and if all
connections would have water meters real cost could be charged. Another option – as a flat rate –
would be to include the cost for water in the fee for the lease. A separate study on the willingness to
pay in the Trinidadian context should be carried out before an introduction of ‘cost for water’ would be
introduced.
16.9.4 Farmers Involvement
An important aspect in operating irrigation schemes is that of training and management. Introduction
of irrigation systems usually comes with technically more sophisticated farming practices. To make it
all possible farmers should be well organised. They have to run their irrigation system, they have to
farm their lands, they have to organise packaging and transport and they have to find the market.
Also, it might be required to introduce more temperature tolerant varieties of crops, if the projected
rise of temperature in coming decades will occur. Famers associations would help to carry out these
activities efficiently and would offer the benefit from economies of scale. It also would create an
environment that is helpful for farmers to add value to certain commodities.
16.10 Funding of the Implementation of the Felicity Irrigation Project
The European Union is granting the republic of Trinidad and Tobago a fund for the National
Adaptation Strategy for Sugar (NAS) through the Accompanying Measures for Sugar Protocol
Countries. This occurs under the Multiannual Indicative Programmes 2007-2010 and 2011-2013. The
grant funding in total for these two programmes was approximately 75m Euros. The Multiannual
Indicative Programme 2007-2010 has been completed now and the funds have been spent. The
grants under the 2011- 2013 Programme (approx. 31.7m Euros) are being disbursed directly to the
treasury of the government of Trinidad and Tobago. The implementation of the Felicity Irrigation
Project is sought to be financed from the 2011-2013 Multiannual Indicative Programme by a request
from the Ministry of Food Production, via the Public Sector Investment Programme (PSIP), from the
treasury.
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17. CONCLUSIONS AND RECOMMENDATIONS
Positive Impact on the socio-economic situation
Turning the former sugar lands of Caroni (1975) Ltd. in cultivated and irrigated farm lands, will have a
positive influence on the regional socio-economic situation. The arrangement to use the property for
agriculture shall generate positive economic returns, resulting in increased rural income and creation
of employment. When the irrigated farm lands prove to be profitable, than workers will be attracted to
these areas. Farmers will produce a wide range of fresh agricultural products, which most likely will
adjust prices downward. Consumers will benefit from healthier agricultural products at lower prices.
Also the issue of food security will be enhanced.
Negative environmental impacts & mitigation measures
Potential negative environmental impacts of irrigation systems may be caused by agricultural runoff
on surrounding rivers and downstream users, affecting water, soil, flora and fauna (biodiversity),
landscape, and human health (pesticides &fertilisers, re-use of waste water). In the design of the
preferred option for irrigation services in the Felicity Project Area, climate change as an outside effect,
has been taken into account. For Trinidad and Tobago it is expected that in the future longer, drier
summers, shorter and more intense rainy seasons, and a potential increase in sea level will occur.
Because of expected higher frequency and intensity of tropical storms, more flooding in low lying
areas is foreseen. Most negative environmental impacts can be diminished by specific mitigation
measures.
Options for irrigation water
Four sources: The consultants have identified four possible sources for dry season irrigation water
supply:
1. The Caparo River in the project area.
2. Groundwater abstracted in or close to the project area.
3. Upstream reservoirs and conveyance of water to the Project Area:
Large existing, flooded mining pits east of the Project Area, adjacent to the Caparo
River, the Ravine Sable Sand Pits (RSSP).
The Caparo River dam (Mamoral), formerly only planned for flood protection, now
under consideration as multi-functional reservoir.
Abels Clay Pit, now still being mined under a current license.
4. Treated wastewater re-use and drainage water re-use:
Conveying treated wastewater from outside the project area directly to the project
area.
Within the project area, by collecting the outflow /drainage and re-using it by mixing it
with the selected irrigation water source(s) – closed loop.
Combinations of more than one of the above water sources can (and have to) be considered.
The consultants concluded that there are two viable options to provide irrigation water to the Felicity
Pilot area. Both include the individual ponds and a system to replenish these ponds.
Option 1: Source water from the Ravine Sable Sand Pits, possibly in combination with the Mamoral
Dam Reservoir, conveyed to the Felicity Pilot Area using the Caparo River. This will include intake
works and a large number of big pumps on the Caparo River within the project area. During the rainy
season the natural flow of the Caparo River can be utilized to replenish the ponds. During the dry
season water can be released (pumped) from the Ravine Sable Sand Pits into the Caparo River bed.
Option 2: Source water from the Ravine Sable Sand Pits, possibly in combination with the Mamoral
Dam Reservoir, conveyed to the Felicity Pilot Area using a pipeline. This will mean that the intake
98
works in the Caparo River may not be needed, and water is available at the intake to be distributed to
the ponds under pressure. This option has the advantage of offering 24/7 supply, resulting in relatively
small flow rates (maximum 170-175 l/s) which can be handled with small pumps and a pipe diameter
of about 50 cm (20 inch).
Closed loop system: Adding the closed loop re-use system to either of the above options will reduce
the required amount of ‘fresh’ irrigation water. The effects of applying this interesting concept will have
to be modelled; a rough estimate can probably and possibly be done quickly. Introduction of the
closed loop system has a clear and negative effect on leaching requirements. It is recommended to
implement this only after an additional study into the effects on the soil salinity and the economics.
Phases: The consultants suggest that Option 1 and Option 2 are considered as Phase 1 and Phase
2. It is recommended to start with Option 1 for a limited number of plots (100-120) in the Felicity area,
and then start the preparations for building the pipeline. The process of detailed survey, detailed
design, tendering, possibly expropriation and compensation (along the right of way), construction and
delivery can then take place without delaying the introduction in the Felicity Area.
Recommendations
The following recommendations can be made:
Develop and follow a clear policy which outlines the allocation of water under circumstances
of water scarcity. Cutting off the entire supply to agriculture from a shared water supply
should only take place under exceptional circumstances. Management of shared resources
should be aimed at optimising the dual use of the resource.
Construct a conveyance system for water to the Felicity irrigation area if and when a
treatment plant will be build (e.g. in Chaguanas Town), which is upstream from the Project
Area.
Carry out a study on introduction of farmers associations and willingness to pay for irrigation
water.
Provide organic manure, as alternative fertilisers, to the Caroni (1975) Ltd. farms from the
large volumes of organic waste to be generated in the Felicity area when under irrigation.
Conduct a sensitivity analysis of crop water requirements under the projected climate change.
Carry out an economic analysis and market study for the future Felicity irrigation area.
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ANNEXES
102
ANNEX 1 MAP OF FELICITY PROJECT AREA
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ANNEX 2: ACTIVITIES OF SUPPORTING STAKEHOLDERS
17.1.1 The Water and Sewerage Authority (WASA)
The Water and Sewerage Authority (WASA) was established by an Act of Parliament in 1965 to
manage the water and sewerage sector of Trinidad and Tobago. An essential component of WASA’s
mandate is the delivery of a safe, reliable and efficient water supply to satisfy the demand of all
sectors of the economy, including agriculture.
The vision of WASA can be described as follows:
Being a customer service business.
Delivering consistent, reliable, water of good quality, and wastewater services.
Achieving sustainable financial self-sufficiency.
Enabling employees to be motivated and well trained, providing a platform for future growth.
Improving the organization's impact on the environment and pursue water security for T&T.
Water Pollution Rules 2001 (amended 2006) WASA facilities the water and wastewater treatment plants to discharge effluents into the
environment, and as such apply for source registration of these facilities and permits. To date, the
Water and Sewerage Authority has identified 66 facilities that require source registration and has
submitted all applications for these facilities.
The Water Pollution Rules were enacted in March 2007 and was designed to protect the freshwater
systems. It prohibits any person or organization from releasing water pollutants that exceed the
permissible level and that may cause harm to human health and the environment. Any person or
organization involved in any activity that releases a water pollutant into the environment must register
as a Source and subsequently apply for a Permit to discharge into the environment. Exceptions
include: releases from normal operation of motor vehicles used for transportation, releases from
domestic households such as laundry, kitchen, shower etc., and discharges of sewage into sewerage
facilities.
17.1.2 Water Resources Agency (WRA)
The Water Resources Agency (WRA) was appended to WASA as a division in March 1976 and is
responsible for the management and control of the Nation’s water resources, including agriculture.
Integrated Water Resources Management, requires collaboration with a range of stakeholders to be
able to make decisions in a sustainability manner. Key stakeholders of WRA are: Environmental
Management Authority (EMA), Ministry of Works and Transport Drainage Division, Ministry of Food
Production, Land and Marine Resources (MFPLMA), Ministry of Public Utilities, Office of Disaster
Preparedness and Management (ODPM), and the Meteorological Services of Trinidad and Tobago
(MET).
WRA’s mission is to manage the country’s water resources effectively and promote conservation of
these resources in a cost effective and integrated manner to support socio economic growth.
WRA’s functions are to manage the country’s water resources in a sustainable manner, using the
Integrated Water Resources Management (IWRM) approach. To promote development, conservation
and protection of water resources.
WRA’s objectives are:
Undertake water resources monitoring and assessment with respect to quantity and quality.
Undertake water allocation, regulation and licensing of water abstraction.
Undertake water resources planning, investigations and development.
Promote and coordinate the implementation of IWRM.
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Develop and maintain a National Water Resources database and information system.
Monitoring and Assessment
The Agency’s data collection system comprises a monitoring network of gauges, which measures and reports rainfall, stream flow, groundwater, evaporation and water quality at strategically located sites throughout Trinidad and Tobago. The data provide information on trends in the quality and quantity of surface and groundwater resources and are required for social and economic development and protection of the environmental.
For planning and management purposes, such as industrial development and agricultural projects,
the collection of reliable data is a basic activity conducted by the WRA. Both mechanical and real-time
automated equipment are utilized for data capture. The use of telemetry has allowed WRA to provide
organizations such as, the Meteorological Services of Trinidad and Tobago (MET) and the Office of
Disaster Preparedness and Management (ODPM), with early warning information on extreme events.
Abstraction licenses
WRA issues water abstraction licenses, which are legal contracts granting a water use right, which is
a right to use water abstracted from a surface or groundwater source. This license does not confer
ownership of the water, nor does it guarantee the quality of the water or the required volume of water
to be abstracted. It provides for re-allocation of water in circumstances of emergency, at times of
scarcity, and in cases of competing applications. Also, it assures that no license will be granted that
may reduce the volume of previous allocations. The license to permit abstraction of surface and
groundwater consists of the following requirements and restrictions:
Limits the volume of water to be abstracted on a monthly basis.
Limits the use to which water can be produced.
Limits the duration and validity of the permit.
Specifies the method for measurement of volumes of water to be abstracted.
Restricts the source(s) from which abstractions may be made.
Expires at the end of year in which it is granted.
Requires renewal at the end of a calendar year.
Requires compliance with the terms and conditions under which the license is issued.
Specifies that violation of the terms and conditions of a license gives rise to an offence.
Requires approval of the Ministry of Works, Drainage Division for the construction of any
proposed structure in or on the banks of rivers for the diversion of flows.
Above restrictions and requirements are relevant for the development of irrigation schemes.
Extension Training & Information Services (ETIS/MFP)
The Extension, Training and Information Services Division (ETIS) is an arm of the Ministry of Food
Production with the mandate to provide information in aspects of agriculture and related issues, with
the aim of assisting farmers in increasing efficiency in production and hence increasing profitability.
The Division continues to seek ways to improve the delivery of service to their clientele who are
spread throughout the various counties on the island.
Vision
To be the premier learning agency for agricultural development and growth.
Mission
To promote the empowerment of our clients through an extension service, which is client oriented and
responsive to changing needs and circumstances.
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Function
To provide farmers, potential farmers, communities, youth and other interested persons, with
information on aspects of agriculture and related issues. To support the regional based extension
service by providing multimedia learning resources and conducting staff training. The eventual aim is
to increase efficiency of agricultural production, leading to increased profitability of enterprises and
improved livelihoods of clients. Staff also participates in exhibitions, field days and other activities as
requested.
Services
On-farm demonstration, trials, farmer field schools.
Provision of audio, visual, publications and printed materials.
Training courses at the Ministry's Offices and within communities.
National Agricultural Marketing and Development Corporation (NAMDEVCO)
The National Agricultural Marketing and Development Corporation (NAMDEVCO) is a statutory body
created by Act of Parliament No. 16 of 1991, with a mandate ‘to create, facilitate and maintain an
environment conducive to the efficient marketing of agricultural produce and food products through
the provision of marketing services and the stimulation of business investment in the agro-industrial
sector of Trinidad and Tobago’.
Vision
Leading Trinidad and Tobago in agricultural marketing and agribusiness solutions, that will contribute
to the social and economic well-being of all our stakeholders.
Mission
Committed to the growth and sustainability of Trinidad and Tobago’s agricultural sector by offering
agribusiness and marketing solutions, through commercial partnerships and linkages with key
stakeholders, in order to produce high quality and value-added food products at fair and competitive
prices, to targeted markets.
Agricultural Society of Trinidad and Tobago (ASTT)
Founded in 1839, the Agricultural Society of Trinidad and Tobago (ASTT) is the only national
organisation representing farmers. As a Statutory Body within the Ministry of Food Production, Land
and Marine Affairs, the ASTT represents every sector of Agriculture.
The ASTT is managed by a committee comprising representatives of all spheres of agriculture,
elected at an Annual General Meeting. Its mandate is not only functioning as an advocacy body, but
also to assist and encourage the development and advancement of all sectors of agriculture.
Over the years, the ASTT has formed alliances with other agencies and organizations, both nationally
and internationally with the main objective of strengthening the agricultural sector.
Vision
To position the ASTT as the flagship for agricultural development in Trinidad and Tobago.
To reposition the agriculture sector as the engine of growth in the national economy.
To achieve food security for all our people by making local foods available and affordable.
Mission
To represent and advocate the interest of all branches in the agricultural sector and to consider,
encourage and advance the growth and development of agriculture in Trinidad and Tobago.
Trinidad and Tobago Agri-Business Association (TTABA)
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The Trinidad and Tobago Agri-Business Association (TTABA) was established in May 2006 by private
sector agri-business stakeholders with government support, to accelerate national economic and
social development through the sustainable expansion of the agri-business sector.
As a ‘for development not for profit company’ TTABA is not owned by private shareholders, but by its
current 33 member associations, drawn from every level of the agri-business sector. TTABA cannot
disburse dividends or profits to individual members, but must reinvest its profits to further its objective
of leading the development and expansion of the agri-business sector in Trinidad and Tobago.
Vision
To be the acknowledged leader of an innovative, competitive, sustainable and social expanding agri-
business sector and one of the main drivers of economic and social development in Trinidad and
Tobago
Mission
To lead the sustainable expansion of the agribusiness sector in Trinidad and Tobago, through the
development of strategic agricultural industries and the provision of innovative agribusiness services
along the value-chain.
Services
The core business is the provision of technical services for the development of selected agricultural
commodity/industry value-chains, and the provision of high quality agro-processing services.
The strategy is to develop agro-industry value-chains and provide agro-processing services to support
3 critical pillars of national development: health/nutrition/security, bio-energy security, and
environmental security.
Agricultural Development Bank
The Agricultural Development Bank has had its roots firmly entrenched in the annals of the history of
Trinidad and Tobago. The Bank’s history dates back to the 1800s when the ‘Agricultural Bank’ was
established as a mortgage lending institution in the wake of a disastrous hurricane. Its immediate
objective was to assist plantation owners to replant their estates. Thereafter, it continued to operate
on a small scale due to restricted legislation and limited financial resources.
Today, the Agricultural Development Bank has truly come of age. It has developed from an agency of
colonial administration into undoubtedly a national institution, providing the major source of funding for
the agricultural, agro-industrial and rural sectors in Trinidad and Tobago. It has developed into a very
important Development Financial Institution (DFI), with a major role to play in the growth of the
national economy.
Vision
To be the first choice for complete financial and support solutions to transform agriculture into a
dynamic, sustainable and competitive sector, which promotes socio-economic development.
Mission
To facilitate sustainable socio-economic development of the agribusiness and rural sectors through
strategic partnerships with our stakeholders, delivering cutting-edge financial products and services to
satisfy our internal and external customers, utilizing a team and customer-focused approach.
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ANNEX 3: Farmers consultations, rapid appraisal,
Consultation with farmers, living 5-6 kms east of the Project Area, in a region where formerly
tobacco was grown (Depot Road), July 9th
2013
At Depot Road an area of 72 acres is served by a water pumping station that extracts its water from a
pond. Most farmers own 3 acres, some have an area of 5 acres. In the nineties the farmers ceased to
grow tobacco, because it was not profitable anymore. The FAO stepped in in 2010 with a project to
facilitate the change from tobacco to crops. The shift to crops and vegetables had not been a major
problem. At present sweet potatoes, hot peppers, sorrel and corn are grown. The farmers can
continue crowing crops in the dry season, because the pond never falls dry. This pond, which in fact
is a small reservoir of about 1 ½ acres, has a dam and has a spring as its source. It was constructed
for tobacco production, using pipes to distribute the water to the land. The MFP provided 3 pumps for
the reservoir, which are operated by the famers. The famers do not pay for the water distribution and
even not for the diesel for the pumps. Some farmers were prepared to pay for diesel but others not,
with the result that after a while nobody contributed anymore. The pumps are operated in the dry
season, but also in the wet season during dry intervals. The water is also used as a source of drinking
and household water. One of the reasons to irrigate is to prevent the soil to harden. Farmers said that
the soil could become hard as concrete. The present system used for irrigation is drip irrigation
through plastic hoses (‘spray pipes’). The price of this material is 180 TTD for about 90 m of hose,
which is considered acceptable by the farmers. In this area farmers do not operate wells or use
groundwater. The farmers hire labourers to plough their land, which costs about TTD 200 per acre.
They expressed the will to get subsidised (‘incentives’) for that by the government and found it more
important than the incentives for vehicles. The farmers told that there is a lack of agricultural workers
in the region. Young people tend to leave for the towns and prefer to work in other kind of businesses.
RAPID APPRAISAL
Consultation with farmers working in the Felicity Project Area, August 12th
2013
On August 12th the County Caroni Extension Office (Chaguanas) of the Ministry of Food Production
organised a consultation meeting with 8 famers who work in the Felicity Project Area. The intention
was to obtain insight in what the famers do, what their wishes are, and what problems they face.
The information was gathered with the help of the followings questions and remarks, which were
brought forward to the farmers:
Are you an ex Caroni worker?
Are you a farmer?
Full-time farmer?
Are you interested in subletting the lease?
What crops do you grow?
What crops would you like to grow?
Do you think you could earn good money with your crops?
Are you happy with the lease conditions?
Do you need assistance to be a successful farmer?
What type of assistance would you like to get?
Do you know about IPM: Integrated Pest Management?
Do you practise IPM?
Do you make use of Incentives (subsidies)?
Do you need assistance in registering as a farmer to get incentives?
Do you have crop insurance?
Would you like to make use of an irrigation system?
Would you pay for the investment?
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Would you pay for irrigation water?
What are the problem that you face?
Do you have wishes?
Results
The following information could be gathered from the questions and remarks, and from the
discussions held with the farmers:
In the Project Area work both ex-Caroni workers, who have one or more leases on their name, and
farmers who have no lease themselves. One farmer had 4 leases on his name (one himself, 2 of
sons, 1 of deceased family member) and managed several leases of 2-acre plots from other lessees.
The 8 consulted persons were all farmers, worked all full time as farmer and like to do that.
The farmers who have one or more leases on their name are not interested in subletting the lease,
because they are interested in farming. However, it is known that other persons who have a lease on
their name, and are no farmers, are interested in subletting.
Crops that are grown by the farmers are: hot pepper, cucumber, egg plant, cassava, eddoes, occra,
corn (limited), pumpkin, and caralli.
Additional crops that the farmers would like to grow are: sweet potatoes, tomatoes, water melon.
All farmers have the opinion that they can earn a good living with farming in the Felicity Area. They
are optimistic about the future, especially if they can carry out irrigated farming. There is a fair trust
that prices for crops will be good and stable.
The lessees were not satisfied with the lease conditions, because the leases are only granted for 30
years. They would like to have a lease of 99 years and preferably they would like to buy the land.
Both reasons were mentioned also to safeguard their farming business for their children/family.
Assistance to be a successful farmer was felt necessary for:
Good roads and bridges / infrastructure
Irrigation system
Water security
Training, a.o. in continued training in Integrated Pest Management
Tractor pool
The farmers are familiar about Integrated Pest Management (IPM) and do practise IPM. They buy as
much as possible ‘safe’ pesticides, the pesticides that are not persistent. They want to use IPM also
to market their crops and get the confidence of the consumer.
Some farmers made use of government incentives (subsidies) to buy equipment and a tractor. Other
famers are not officially registered as a farmer and therefore cannot make use of the offered
incentives. This is felt as a problem.
None of the farmers have a crop insurance. The premium is too high.
All the famers would like to practise irrigated farming. It is most wanted in the area.
If a reliable irrigation system would be installed and maintained by the government, then some
farmers are prepared to pay an affordable fee for the investment. But only when all farmers actually
pay.
If irrigation water can be delivered at their plot(s) and the system is reliable, then most farmers are
prepared to pay for the water. But only if all farmers pay.
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There is a need for a farmers association, but it should be an association of directly involved farmers
in the area, and not a ‘distant’ organisation. In the association the famers could make agreements and
decisions concerning the management of an irrigation system, transport, marketing etc.
Problems that the famers face are:
A lack of water
Security, crops are stolen, a gate system might help
Complaint of the farmers: there is a lease tax of TTD 200 per year, which is not felt as high, but not all
farmers pay the tax.
Wishes of the farmers are:
Irrigation system
Expansion of area to cultivate; there should be a first preference for ex-Caroni workers to
lease/buy land which has not been distributed yet
Excess roads, good bridges
Tractor pool
There was one senior farmer who has clear ideas about the setting up of an irrigation system in the
Project Area. He would like to discuss such a system with irrigation engineers and is prepared to
make drawings to explain his views.
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ANNEX 4: INTERNATIONAL EXPERIENCES WITH WATER USER ASSOCIATIONS
SOUTH AFRICA
After: Empowerment of the poor through agricultural water user associations. Draft Policy Document, Department of Water Affairs and Forestry for the Management of Water Resources, Pretoria, South Africa, 13-02-2002.
Water User Associations and Cooperative Governance
Poverty often goes hand in hand with a range of problems that prevent the poor from contacting those
government officials who could provide much needed support. One aspect of these problems is the
complexity of the support structures that government provides. There are a variety of government
departments, each with their own mandates, which have a range of support programmes for the poor.
To the uninitiated, it may not always be clear that support is available, how support can be accessed,
or how various programmes work together to provide support from a range of angles. In some cases,
despite the best intentions, support systems may be contradictory or difficult to implement in an
integrated fashion. In addition, it may often be the case that support from one department is
ineffective unless it is tied to support from another department. The use of effective systems of
cooperative governance is therefore a key element in poverty alleviation. As a result, it is important to
address this issue within the context of WUA policy.
The first question that needs to be resolved in this regard is the question how WUAs can access the
support of a range of government departments at once, generating a ‘virtuous circle’ of development.
Users may decide to allow their WUA to perform a range of different functions, not all of which are
necessarily related to the management of water. This means that the activities of a WUA may be
relevant to more than one government department. Also, the success of a WUA may require support
from a range of different government departments. For example, a WUA that has been established for
irrigation purposes could require the following kinds of assistance:
from the Department of Water Affairs and Forestry for the management of water resources
from the Department Land Affairs to increase the security of land tenure amongst farmers;
from the Department of Agriculture for the provision of extension support and advice in increasing production;
from the Land Bank for a production loan;
from the National Agricultural Marketing Council to receive advice on products and marketing;
from the Department of Public Works for the establishment of community assets such as storage facilities;
from the Department of Trade and Industry for training in managing a business ad facilitating market access.
It can be seen from this example that WUAs hold a lot of potential with regard to the pursuit of
cooperative governance. However, it is important that the mechanisms for cooperation among
government departments be clear and unambiguous if the system is to serve WUA members
adequately. Currently a policy proposal has been submitted to Cabinet that suggests that henceforth,
all proposals that relate to agricultural water use be submitted to the Provincial Irrigation Action
Committees (IACs) for approval. It also suggests that the membership of IACs be broadened to
include all government departments that initiate projects that are related to agricultural water use.
This includes the Department of Public Works and the Department of Health.
Alongside IACs, increasing emphasis is currently being placed on the role of local government in
integrating the deliverables of the various line departments into local development plans. In terms of
the Integrated Sustainable Rural Development Strategy (ISRDS), it is expected that any services
required of government departments by community institutions will be obtained through the mediation
111
of district councils. Thus District Councils are available to WUAs and other localized water
management institutions for the submission of development proposals.
Where there is lack of clarity with respect to the institutional vehicles for cooperation, it is likely that
the relevant Catchment Management Agency will, through the implementation of its catchment
management strategy, facilitate liaison between departments on project proposals.
A second question relating to cooperative governance relates to the fact that WUAs are not the only
institutions that manage water for the benefit of their members. As a result of the initiatives of a range
of government departments aimed at the provision of specific support at community level,
communities have the choice between a range of institutions through which they can achieve their
aims. Examples of these are Communal Property Associations, Community Production Centres,
Trusts, Sect. 21 companies and the Water User Associations treated in this document. In line with the
principles of cooperative governance each ministry needs to ensure that no one institutional format
excludes a community from the provision of support by another line department. What is required to
facilitate this is the development of a memorandum of understanding between relevant government
departments that enables each community structure to access support from all government
departments if the activities of that community structure fall within the mandate of the department in
question.
This also requires a policy decision to be made within the Department of Water Affairs and Forestry in
relation to the conditions under which it is prepared to provide its grants and subsidies to local level
community organisations other than WUAs. It could be argued that if an organisation other than a
WUA is using water for the benefit of its members, it should be treated as a WUA in principle, as it
could have opted to register as a WUA under the National Water Act.
A third matter falling under the broad heading of cooperative governance is the opportunity presented
by WUAs to contribute to the reconstruction of communities that were fragmented and divided by
apartheid. If well established, WUAs are likely to achieve the purpose of the Act such as redressing
imbalances created in the past , promoting equitable access to water and facilitating social and
economic development (section 2, NWA). All these are a means to reconstruction and development.
Not only is promoting social cohesion a fundamental goal of the Integrated Sustainable Rural
Development Strategy, it is also mentioned by community facilitators as a precondition for sustainable
institutional development in poor rural areas. The creation of strong local level institutions such as
WUAs which can bring different groups together in a common vision therefore presents a social
challenge that goes beyond the strict confines of water management and contributes to rural
integration in a broad sense. The establishment of strong WUAs is a function of the quality of the
public consultation process that has brought the WUA into being.
Lastly, WUAs are an important institution through which the National and Provincial Departments of
Agriculture can implement their programme of irrigation management transfer (IMT) which transfers
the management of government initiated irrigation schemes to the users. Close cooperation is
required between the two departments to ensure the achievement of agricultural and water related
objectives, as well as the smooth transition to user-managed institutions.
Functions of WUAs This section is intended to clarify the functions of a WUA. In doing so, it also intends to provide some
clarity on the question how WUAs should be delineated from and link in to umbrella structures of
water resource management.
A number of issues are important in considering the differences between various tiers of water
management, namely:
1. The function that the institution has been established to perform. Four key functions of water institutions can be identified, namely:
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Operational functions, related to the management of a service;
Bulk supply functions, related to the management of a bulk water supply system
Resource management functions, related to the management of the resource;
Representation functions, related to the representation of stakeholder needs at higher institutions of water management
2. The functions mentioned above each require a certain nature and frequency of the communication between members or sub-aggregate units.
3. The commonality of vision and purpose amongst members or sub-aggregate units.
Of these, the key issue in distinguishing between various tiers of water management institution is the
functions that they are intended to perform. However, this is also strongly related to the commonality
of vision of members of base WUAs. Thus WUAs may for instance be formed as a result of an
attempt to overcome poverty. Cultural bonds may equally foster mutual ties out of which such an
institution can be built, and such natural social cohesion forms a strong basis upon which to form an
institution. The social fragmentation generated by the past may act to destabilise institutions if
communities which do not see eye to eye are forced to cooperate within the context of one institution.
The pursuit of social cohesion, it is argued, belongs to a long term rather than a short term strategy. In
terms of WUA policy this means that while base-level institutions may be formed on the basis of a
self-defined group, one task of umbrella bodies will be to foster cooperation among these base
institutions over the long term.
A natural unit for base-level WUAs is an institution that has been established to manage a water
service. In addition, individuals who can interact with each other on a day to day basis may form a
more natural unit for a base-level WUA than structures in which communication is limited by
geographical reach. This is because they can reach each other on foot and can communicate verbally
to each other. Furthermore, a WUA has natural strength if there is a commonality of vision based on
the shared views of its members.
A natural unit for umbrella structure is an institution devoted to the management of macro-
infrastructure common to numerous smaller WUAs, or to the allocation of the resource along a stretch
of river. Policy already exists which makes provision for such a structure in the form of the envisaged
catchment management committee. In other words, an umbrella structure manages a common
resource. At this higher level of operation, daily communication is usually no longer possible. This will
in most cases, be compensated by regular meetings between groups making use of a system.
This argument suggests that there is a natural distinction between the functions of ‘base’ water user
associations operating at a local level and that of a catchment management committee which should
operate at a somewhat higher level. The catchment management committee is made up of elected
members from all the water user associations in their area of jurisdiction. CMC act as conduits for
issues from the local level to the CMA. The differentiation between the two levels is based on the
nature of the functions that need to be carried out at each level. As a statutory body, the catchment
management committee may enter into legal transactions when the need arises. Thus representation
becomes a key ancillary function of this first aggregate level of water management institution.
Furthermore, by virtue of their management of the resource, catchment management committees
have the ability to intervene in a system in the interests of equity - for instance on behalf of tail end
users. This provides a point of entry for the Department of Water Affairs and Forestry - or the CMA -
with respect to the promotion of equitable access to water both during the establishment and during
the operation of primary WUAs. This would be done within the context of each local catchment
management strategy, which should also spell out the roles and relationships of the different
institutions in the water management area. Ideally, catchment management strategies should have
developmental chapters setting out the overall equity goals of the water management area.
Another unanswered question is how WUAs will link into the Integrated Sustainable Rural
Development Strategy (ISRDS), which operates from District offices in response to requests
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submitted by local authorities on the basis of community development visioning processes. Given that
the ISRDS seeks to integrate the rural upliftment strategies of a range of government programmes for
poverty alleviation, it impacts on the establishment of those WUAs which will contribute to the
empowerment of small scale farmers.
INDIA
After: Water Users Association for Sustainable Water Management, Experiences from the Irrigation Sector, Tamil Nadu, India. C. Chandrasekaran, P.T. Umashankar, V. Duraiswaminathan, R. Jayakumar, UNESCO New New Delhi Office, 2002.
Strategy
The strategy for organising farmers was drawn from thc cxperience gained by CWR in organising W A
Sin four tanks under a project assisted by the Ford Foundation, India. The approach gavc importance
to working directly with farmers and gave priority to their concerns rather than implcmcnting a
preconceived action plan. Farmers were asked to identify their own priorities and concerns, which
were an integral part of the implementation process. After about two months of intensive village
contacts, the first farmers’ meeting was organised. Fifty scvcn farmers attended the meeting as
representatives of the ten villages. The farmers resolved to form a WUA for thc entire command and
to accept turnover as the ultimate aim of the association. As a first major step towards the formation
of the NK channel WUA, an advisory committee was to be constituted with at least two (not more than
four members) from each of the ten villages. There after farmers in each village met to select their
representatives and the advisory committee was formed. The committee divided itself into several
adhoc committees for such purposes as mobilising resources, organising farmers support, and
women’s participation. Farmers were involved in motivating others to join the WUA through regular
visits and meetings in every village and hamlet.
The advisory committee was treated as a general body in order to select the office bearers of the EC
of the WUA. The office bearers consist of a president, two vice presidents, a secretary, two joint
secretaries, and a treasurer. Additionally, the general body unanimously selected twelve EC
members. Women have 30 percent representation in the EC. The channel level WUA helped organise
village level or branch WUAs. They are called the Branch WUAs on the channel. The latter ensure full
participation from each village. They help in the collection of subscriptions, development of leadership
and quick administrative response. Apart from these, women farmers formed a separate WUA. The
entire branch WAS, as well as women WAS, are affiliated with NK Channel WUA.
One advantage of the NK Channel command is the existence of a strong tail-end WUA, the
Vagaikulam Land Holder Association, which has been hnctioning since 1945. Being among the most
deprived, the tail-end farmers of Vagaikulam as elsewhere are keen to get water. The Vagaikulam
WUA developed the capability to work collectively to ensure the availability of water. It supported any
organisation that could bring order to the entire system and become the approach as well as the
principal motivator for the creation of a functional WUA for the NK Channel as a whole. Women in
WAS. A notable feature o f the NK Channel experiment i s the importance given to the role of women
in agriculture and irrigation. Women play a vital role in all phases of irrigated farming, as marginal and
small farmers constitute the majority of the farming community. The initial impetus for women’s
participation came from the Vagaikulam Farmers Association, which had women members in the
WUA. In order to motivate women, weekly meetings were organised using women leaders and
women’s groups. Even male farmers, particularly key farmers, were persuaded to commit themselves
to including women in the WAS. A committee of four women and one man wasspecifically constituted
for women development and for integrating women into the turnover process.
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Advantages of the WUA formation to solve environmental issuesThe formation of WUAs has brought
down some of the environmental problems. For example, the water logging and salinity problems
were experienced during pre-WUA period in 40 percent of the surveyed schemes. These problems
were more pronounced in both tank and canal irrigation schemes. The p o s t - W A period showed
improved situation due to (a) controlled and regulated supply of water in the canal due to the
application of effective water distribution system and (b) canal improvement works. Nearly 50% o f the
schemes have experienced slightly poor quality of groundwater below theiayacuts (command area).
Four out of six schemes that have yielded below normal level of crop productivity during pre-WUA
period have indicated just normal yields during the post-WUA period, Same number o f schemes has
shown above normal level of yield from normal level of yield after WUA formation. Farmers perception
i s that it happened due to (a) application of right quantity of water at right time, the consequence of
proper distribution pattern, (b) reduced water logging condition, (c) awareness about soil, water and
crop management aspects. Their awareness was judged by asking them about the requirement of
training on the above aspects. 83%, 90% and 93% of the farmers do not want training on water, crop
and soil management respectively. However 85% of the farmers want training on WUA management
especially on how to raise the resources and how to deal with the Government departments
EGYPT
After: The role of water users’ associations in reforming irrigation. Nile Water Sector, MWRI, Ministry of Water Resources and Irrigation, case # 110, Abdelfattah Metawie, 2002.
Water resources Egypt’s water resources are severely constrained, at less than 1000m3 per person. This calls for
increasing the water use efficiency by improving irrigation management practice, as the agriculture
sector is the main user of water resources. Much of the irrigation infrastructure is elderly and in need
of rehabilitation. The irrigation improvement program (IIP) is one of the large-scale projects to help
Egypt in the 21st century in order to sustain its ambitious development plan. The program involves a
combination of technical changes and infrastructure investment, together with institutional and
organisational changes in the way irrigation water is managed. Of key importance, Water Users’
Associations playing a major role in decision making and the operation and maintenance of the
pumps and mesqas by themselves, with minimal assistance from the Irrigation Advisory Service (IAS)
staff. The fundamental change introduced by the irrigation improvement is to replace individual farmer
pumping at multiple points along the mesqa (irrigation ditches) by collective single point pumping. In
addition to the above primary aims, there are many other aspects to the project, including intensive
training for water users, the IAS, and all levels of personnel involved to the top of the ministry; special
studies and seminars, workshops to help the execution of such a program.
Lessons learned
− The new programme has been built of the experience if earlier irrigation programmes; there is a
body of knowledge that has been tested and piloted which provides underlying strength to the new
reforms.
− In order to increase the efficiency as well as the performance of the system, users’ participation in
the management is a must since their decisions and ideas have a great impact on the operators and
the modernization process of the systems would assure the sustainability of the system.
− Increased crop production and achievement of real water savings in the system is dependent on the
awareness and understanding of both users, and operators and managers of the system.
− Increasing the capacity of users, operators and managers require intensive training. Now in Egypt
the new generation has accepted the concept of users’ participation in the management and the
MWRI has legalized the formation of water users’ association.
115
Water users associations (WUA) The idea of water users association is broadly accepted now in many of the areas where the Irrigation
Improvement Project (IIP) is to be implemented. The idea needs understanding and support from both
sides of the equation of the supply and the demand whether they are decision-makers, planners,
managers and operators in the supply side and users in the demand side. Developing mechanisms
for reaching agreements should occur through dialogue. The experience of forming WUAs has helped
to create a new generation of engineers, technicians, and users, who have become experts in
building the trust between both parties. The on-going challenge is to ensure the continuation of mutual
understanding on all levels of the irrigation system, so that areas where meeting the demands of
users for reaching the potential production as well as defining areas where real water saving could
become reality with less cost can be located.
Investment in people as well as in infrastructure Changes in the software of the system where the rules and roles of operation can be modified are
harder than changes in the hardware of the system such as adding structures. But the impact of
changing the rules and roles is greater where it involves investments in the people by increasing their
awareness of their system, their capacity to run the system within its constraints and limitations.
Acceptance as well as appreciation of the users is greatly dependent on the performance of the
management in meeting the demands of the users with the least costs involved in operating the
system as well as keeping in right shape through maintenance. A seven-phase process has been
developed in the IIP areas for building sustainable Water Users Associations. The seven phases for
building sustainable water user associations are presented at regular intervals in almost all
documents and reports pertaining to IIP. Most descriptions of the seven-phase process (7PP) state
the targeted goals and the way these goals have to be achieved (how it is done), and the steps are
summarised in Table 1. The ultimate goal of the process is to increase total farm income by saving
labour, time spent on irrigation, to ensure good water control for increased production possibilities,
and more equitable distribution of water. Monitoring and evaluation should of course be a continuous
effort and be part of each phase. Apart from special evaluations on the project’s impact, which could
be done in a separate phase, there should be continuous regular monitoring of WUAs and mesqa
progress to feed back into the learning process.
Conditions for effective WUAs One of the most important activities in building sustainable WUAs is system of process documentation
for learning from experience how to improve the process. There are a number of conditions which
help develop effective WUAs. Clear policy guidelines and continuous strong, Egypt: the role of Water
Users’ Associations in reforming irrigation Case #110 9,support from the MWRI and senior officials in
implementation of the new legislation and, developing the appropriate organizational mechanisms for
the IAS Irrigation Improvement, Projects is essential. Other conditions include strong IAS leadership,
and regular meetings, contacts and special training of WUA leaders. The time involved should be
recognised: communication and training support focused on creating understanding and building
linkages with stakeholders should begin in new project areas several weeks before, Phase I activities
and communication support should continue throughout the seven phases. Building strong linkages
and working relationships with district engineers, staff of the MOA, local banks, cooperatives, schools
and influential local legal begins with phase I, "entry" and must continue through all phases into the
future. The investment in time and effort means that it is essential that the benefits of the new
technology and the WUA organization must continue exceed the costs involved if strong and
sustainable WUAs are to be.
After: Assessment Indicators for Water Users’ Associations in Egypt. E-Water, Official Publication of the European Water Association (EWA), Abdel Hakim M. Hassabou, Inas K. El-Gafy, 2007.
116
The analysis, Institutional Aspects • Meetings are not registered and there are no organized files for the WUAs in Kemry canal. WUAs of Mantout and Bustan canals register meetings and keep records for all the activities of the associations in organized files. • Board members are elected. One or all of them can be replaced if their performance is not successful. • In the old land, they have good relation with the IAS officers. In the new land, there is no IAS in the area. The agricultural extension agent meets regularly the IAS officers and also the officers of the Bustan Development Project.
Management and Financial • Managing the activities of the WUA is the responsibility of the board members, sometimes with the help of other members. • Members are informed with all the activities of the board. • In the old and new lands, the woman has the right to participate as a member in the WUA, if she owns the holding. In the old land, she appoints her father, husband or son to replace her in the activities of the association. In the new lands, a woman member appoints another member of the WUU to replace her in the meetings and voting.
Maintenance • The pump breaks down 2-3 times a year except in Mohamed Refat Villag. The pump breaks down 2-3 times a month because the spare parts are not the originals and they do not have a special mechanic for maintenance. They often do the maintenance. • In most cases the average time needed to fix breakout is 2-3 days.
Water use and the Environment • There is a continuous flow of water in the canals and mesqas in Mantout and Bustan canals and a rotation system in Kemry canal. In the new lands water is not available in the mesqas one day a week. • In the old land, traditional system of irrigation is followed, while in the new lands modern systems of irrigation are applied. • Underground water is used if there is a shortage in the Nile water. The problem is the low quality of this water, which causes the salinity of the soil and the decrease in yield.
Socio-Economic Impacts • The costs of O& M of the mesqa and the lifting pump are paid by the members of the WUAs either per hour or per feddan. In WUUs each member pays LE 5-10 per feddan a year, according to the rules of the union and each group of 4 holders is responsible for O&M of their own pump. Usually, farmers pay their (shares) spare parts in the costs. In the new lands each holder pays LE 85/ feddan/ year for the electricity consumption. • Each WUA or WUU has a bank account and a fund for emergency cases except in Sharkia associations. • The cost and the time of the irrigation period have decreased after the improvement of the mesqas and the establishment of water user associations. • All type of farmers in the old and new lands were not accepting the idea of joining a WUA or a WUU, until they visited successful WUAs or WUUs in other areas and after having had a lot of discussions with mesqa improvement agents. • In general, the crop yield has been increased, except in Ahmed Ramy village. In Ahmed Ramy village they cannot say that crops' yields have increased because of the shortage in water during the critical time of plant growth. • Conflicts between members are solved by discussions and convincing.
117
PALESTINE
After: Emergency Capacity Building Project to the Palestinian Water Authority. Technical, Planning and Advisory Team in the Water and Sanitation Sector (TPAT) of the
Water Sector Reform Agenda for Palestine, B. Pengel,17-06-2013.
Water User Associations in Palestine
are primarily seen as within the responsibility of the Ministry of Agriculture (MoA). WUAs are often
formed by groups of farmers who have a shared interest in irrigation supplies for cost and water
sharing, and to coordinate demand with the irrigation water supplier. WUAs can be large or small, and
may be formally constituted (as an NGO) or by informal arrangement. In Gaza for example, many
small informal groups of cooperating farmers exist due to the sharing of wells, where cost-sharing is
not uncommon to avoid disadvantaging farmers further from the well. This approach would be
appropriate for re-use water supplies where a group of farmers may share an off-take, organise the
water distribution and cooperate over the division of costs. These groups could provide focal points
for the operator of the re-use water conveyance system on issues covering water demand and
scheduling, billing, complaints, etc. The PWA has limited experience through a project in Gaza; a
Memorandum of Understanding on the application of treated wastewater has been signed. The MoU
describes the cooperation between the involved ministries and agencies in Gaza to facilitate the
Austrian Project, which is carrying out a pilot on treated wastewater re-use in Gaza. This MoU also
mentions the establishment of Water User Organisations as an important requirement. The PWA in
Ramallah has contacts with the MoA on possible pilots in the Jordan Valley (source: Ahmed Hindi).
While the original TPAT planning mentioned ‘the establishment of Water User Organisations’ the
study up to now showed that this is far too ambitious; the objective has been adjusted to developing
and discussing an overall institutional framework including stakeholder representatives at several
levels, from farmer cooperatives to possibly governorate level water user councils. The experience up
to now also indicated that not just water user associations at farmer level (for joint management of
agricultural inputs including groundwater or re-use water) are needed, but that higher level
organisations at district / governorate level are to represent other water users (industry, domestic,
municipal etc.), with the explicit objective to be a competent partner for the PWA when discussing and
implementing water allocation issues between different uses. While actual influence of these higher
level water user organisations on the water allocation may be limited, they can act as a conduit for
two-way communication on water resources management issues and information.
118
ANNEX 5: DRAINAGE AND FLOODING
1 Drainage and Flooding
In this Chapter an overview of available information and knowledge is presented, providing an
overview of the drainage and flooding situation for the former sugar growing areas, located on the low
areas in the west of Trinidad. Within the scope of this study, which was very limited in time and
manpower, the output is necessarily linked to the available time and available data, as there was no
scope for more than very limited site visits and even the collection of relevant documents and reports.
17.2 Flooding
Flooding was kept at a minimum at Caroni (1975) Limited; there was a permanent crew of workers
which was actively engaged in cleaning the drains, especially after harvesting of the sugarcane. Each
worker had to patrol sugarcane fields looking for pollutants. With the closure of the sugar industry the
routine patrols have stopped and some areas have become a dumping ground, which has contributed
to an increase in the incidence of flooding as drainage channels are blocked (NIRAS 2009, Chapter
5).
After floods in the early years of this century, which caused serious problems in Chaguanas, part of
the flow from the Caparo River now is diverted through the Honda River bifurcation, significantly
reducing or even completely preventing flooding in Chaguanas. The Honda River joins the Caparo
River again just upstream of the Felicity Pilot area.
According to several resource persons the risk of flooding in the Felicity pilot area is limited; if in the
future problems arise another link from the Honda River to a river further to the south (the
Chandernagore River) is also possible, using an existing channel, which will need to be widened.
Figure 1: Flood prone areas in Trinidad and Tobago
Source: MoP 1999
119
While the Terms of Reference for the Felicity Project ask for a study of flooding in the former sugar
growing areas, a full study is well outside the scope of this relatively small project. Meanwhile the
Caparo River Basin Project and the Caroni River Basin Project are being carried out by Royal
Haskoning DHV for NIDCO. These studies presently mobilize much larger resources. It is
recommended to wait for the results of these studies. Also, the main subject for the Caparo River
Basin Project is to devise a flood management and mitigation strategy for the Caparo Basin.
Assuming that this is successful, flooding in the Felicity area should be something of the past.
17.3 Drainage
17.3.1 Leaching and salt accumulation
Drainage is essential for successful irrigation; without proper drainage rapidly rising groundwater
levels may lead to waterlogging and eventually to soil salinisation. In the early years of a scheme,
when ground water levels and salinity build-up in the soil(-water) are still low, drainage could be
ignored but, unless a stable permanent natural drainage pattern develops, artificial drainage is
required.
To avoid salt accumulation in the root zone and related crop damage, a leaching requirement must be
determined. Even if the field application losses of irrigation initially suffice to off-set the salinization
risk, in the long term salinity may still develop. In particular when low quality water is used or
(temporary) under-irrigation occurs additional water will have to be added to the irrigation gift.
Dynamic salt management, leaching during off-peak water use periods or non-cropping periods, is
another viable option and has an added benefit: it reduces peak water demand and design capacity of
the distribution system. Natural rainfall will also contribute to leaching, as the leaching requirement
consists of a yearly total amount of water and a maximum allowable level of soil salinity. Timing and
depth of leaching will depend mainly on type of crop, soil, climate, irrigation practices, rainfall and
rainfall distribution and irrigation water quality.
17.3.2 Salt water intrusion
In general the elevation of the Felicity pilot area is high enough above the mean sea level and even
above the mean flood level to prevent any salinisation of the groundwater. Salt water intrusion in the
groundwater is not to be expected as the groundwater flow is towards the sea due to the clear rainfall
surplus, and there is no well abstraction in the area. The permeability of the subsoil is also rather
limited. The abstractions at the Carlsson well field, about 3-5 km to the east of the project area, might
in theory cause such deep coning that seawater could start flowing into the groundwater aquifers;
large scale abstraction for irrigation obviously increases such risk, but is not now considered. It is
recommended to study the groundwater flow processes in more detail, and to install measurement
wells on the seaward side of the project area, to monitor groundwater level and groundwater quality.
This could possibly be done with automatic loggers.
Salt water intrusion through the main rivers and drainage channels may present a possible problem.
This is certainly the case for the Caroni and Canupia rivers, which have been dredged to a level
where a salt tongue can reach up to the highway at times when discharge is low. For the Felicity area
this may possibly be a problem in limited seaward part of the area, when taking water from drains and
rivers for irrigation. The risk is expected to be very small, though. A weir under the last bridge over the
Caparo River will effectively block seawater intrusion.
17.3.3 Soil drainage
Internal drainage in the Felicity area may be a challenge. A surface drainage system is in place, but
the soils are heavy and in some places the groundwater is relatively close to the surface. Over-
irrigation may cause groundwater to rise to close to the surface, leading to water-logging, and into the
zone of capillary rise, where subsequent evaporation will result in the deposit of salt, damaging the
crops. Care should be taken to limit the irrigation water application to the amount needed for the crop
120
and for adequate leaching: over-irrigation is in the long run as serious a threat as under-irrigation,
unless additional (and in fact unnecessary) drainage capacity is installed. The groundwater level
should be monitored on a regular basis - at least yearly, after the dry season irrigation period. If there
are any indications of rising groundwater or salinisation due to capillary rise to the surface, the
drainage situation needs to be improved, possibly by installing sub-surface drainage.
121
ANNEX 6: CHARACTERISTICS OF AQUIFERS AND WELL FIELDS IN THE CENTRAL SANDS AND LIMESTONE
Annex 6a: Aquifers characteristics of the Central Sands and Limestone
aquifer
unconfined/confined
lithology recharge
area
(ha)
total
thickness
(m)/ total
permeable
zone (m)
specific
capacity
(m3/day/m)
average
specific
capacity
(m3/day/m)
transmissivity
(T)(m2/day)
(estimated)
hydraulic
conductivity(K)
(m/day)
Sum Sum Sand: confined (sub-
aquifers S1-S5):
Unseparated Sum Sum
Upper Sum Sum
Lower Sum Sum (pump test carried out in
Carlsen Well Field)
fine to very fine sand,
some silts and clays
S1 & S2:
375
S3: 132
S4: 445
S5: 182
30-100/30-
100
25-70/25-70
10-90/10-90
55/130/275/2
0/336
163 225
970 (lit.12)
5
22 (similar to
Sum Sum-
Mahaica
Sands)
Sum Sum - Mahaica Sand:
confined (sub-aquifers M1, M2)
(pump test carried out in Las
Lomas Well Field)
fine to very fine
sands, some silts
and clays
M1: 728
(incl.sub-
crops)
M2: 1012
40/40
90(max)/90
60/396/185/
335/17/26-
389 (lit.23)
199 275
1,290 (lit.12)
7
22 (storage
coefficient
0.0003; lit.12)
Durham Sand: confined
(sub-aquifers D1-D7)
fine to very fine
sands, some silts
and clays
D1 & D2: 55
D3: 26
D4: 210
D5-D7: 625
15-75/15-75
15-125/15-
125
20-160/20-
160
20-160/20-
160
124/81 103 140
3
Guaracara Limestone limestone - - - - - -
122
(fossilerous)
Source: Water Resources Management Strategy, 1999
Annex 6b: Characteristics of well fields in the Central Sands and Limestone
aquifer
well field numbe
r of
wells
yield 1995
(m3/year)
yield
1995
(m3/day)
long term
water level trend
bal. yield
per aquifer
De Verteuil
1968(m3/yr
)
safe yield
per aquifer
Dillon
1969(m3/yr
)
safe yield
per
aquifer
WRA
1994
(m3/yr)
Sum Sum Sand:
unseparated Sum Sum
Upper Sum Sum
Lower Sum Sum
1. Carlsen Field
2. Freeport/California (1)
Private wells:
Sub-total:
5
4
10
19
3.98x106
*2.64x106
1.71x106
8.33x106
10,904
*7,229
4,680
22,813
declining:1986-91
upward:1991-94
declining:1994-95
equal: 1986-91
upward: 1991-93
declining:1993-95
**
6.64x106 3.65x10
6
Sum Sum-Mahaica Sand
1. Las Lomas
upper aquifer
lower aquifer 2. Waller Field
Private wells:
Sub-total:
5
-
3
8
3.12x106
*0.53x106
0.02x106
3.67x106
8,548
*1,451
54
10,053
equal: 1991-95
equal: 1991-95
**
11.62x106 4.38x10
6
Durham Sand
Freeport Todd’s
2
*2.19x106
*6,000
equal: 1986-91
upward: 1991-91
6.47x106 2.01x10
6
123
Private wells:
Sub-total:
3
5
0.04x106
2.19x106
12
6,012
declining:1993-95 **
Caroni Surface gravels Private wells 3 0.14x106 370 ** - -
Central Shallow Gravels Private wells 3 0.01x106 32 ** - -
Guaracara Limestone Guaracara; Private wells: 1 0.01x106 35 ** - -
Sub-totals public wells (WASA)
Private wells
16
23
12.40x106
1.89x106
34,132
5,315
TOTAL 39 14.30x106 39,315 (10.0x10
6)
Source: Water Resources Management Strategy, 1999
124
ANNEX 7: WATER QUALITY IN THE CAPARO RIVER Water and Sewerage Authority , Water Resources Agency, water quality, river Caparo, location: north 1,158,770, east 681,735
Period Specific
Conductivity pH
Colour (Hazen Units)
Temperature (OC)
Phosphate (mg/l)
Free Ammonia
(mg/l)
Organic Nitrogen
(mg/l)
Nitrate (mg/l)
TDS (mg/l)
DO (mg/l)
Iron (mg/l)
Sulphate (mg/l)
Turbidity
20-03-1991 470 7.8 70
0.02 0.26
320
1.5 71 15
13-10-2005 123.8 7.4
2.9
1
4.83 0.83 46 15-11-2005 270 7.3
0.89
5.86 2.68
378
09-10-2005 402 7.5
5.8
190
27-10-2007 624 7.7 150 25.3
0.35
533 6.34 4 109 30
27-10-2007 533 7.6 400 25.3
0.33
430 5.83 3.9 85 48
27-10-2007 441 7.5 500 25.1
0.33
362 5.62 6.4 77 57
15-11-2007 640 7.7 60 26.1
0.22
502 6.13 2.9 85 16
15-11-2007 577 7.9 70 27.4
0.23
434 6.18 3.8 84 27
15-11-2007
7.8 50
0.23
440
3.3 83 35
20-11-2007
7.9 60 24.5
0.25
513
3.57 99 26
20-11-2007 567 7.9 100 25.7
0.21
460 5.67 4.3 87 38
20-11-2007 567 7.9 500 25.8
0.46
457 5.67 17.45 86 592
22-11-2007 673 7.9 50 25
0.09
516 6.39 0.6 100 9
22-11-2007 618 7.9 60 26.4
0.09
463 6.14 1.34 83 18
22-11-2007 605 7.7 500 26.4
0.04
462 4.51 13.6 86 116
26-11-2007 490 7.8 400 26.4
0.11
380 6.04 12.84 75 101
27-11-2007
7.6 150
0.18
380
6.95 71 44
27-11-2007 419.8 7.6 500 29
0.17
353 5.01 5.11 67 226
09-09-2008 410 8
32 1.17
4.86 0.04 46 94.9
30-04-2009
7.6
27 1.11 0.3 5.85 2.05 215 1.7 0.49 0.01
125
ANNEX 8: Test results of water samples from project area
Annex 8 Test results of water samples from project area.pdf
126
ANNEX 9: GUIDELINES FOR INTERPRETATION OF WATER QUALITY FOR
IRRIGATION
Guidelines for Interpretations of Water Quality for Irrigation1
Potential Irrigation Problem Units
Degree of Restriction on Use
None Slight to Moderate
Severe
Salinity(affects crop water availability)2
ECw dS/m < 0.7 0.7 – 3.0 > 3.0
(or)
TDS mg/l < 450
450 – 2000 > 2000
Infiltration(affects infiltration rate of water into the soil. Evaluate using ECw and SAR together)3
SAR = 0 – 3 and ECw = > 0.7 0.7 – 0.2 < 0.2
= 3 – 6 = > 1.2 1.2 – 0.3 < 0.3
= 6 – 12 = > 1.9 1.9 – 0.5 < 0.5
= 12 – 20 = > 2.9 2.9 – 1.3 < 1.3
= 20 – 40 = > 5.0 5.0 – 2.9 < 2.9
Specific Ion Toxicity (affects sensitive crops)
Sodium (Na)4
surface irrigation SAR < 3 3 – 9 > 9
sprinkler irrigation me/l < 3 > 3
Chloride (Cl)4
surface irrigation me/l < 4 4 – 10 > 10
sprinkler irrigation me/l < 3 > 3
Boron (B)5 mg/l < 0.7 0.7 – 3.0 > 3.0
Trace Elements (see Table 21)
Miscellaneous Effects (affects susceptible crops)
Nitrogen (NO3 - N)6 mg/l < 5 5 – 30 > 30
Bicarbonate (HCO3)
(overhead sprinkling only) me/l < 1.5 1.5 – 8.5 > 8.5
pH Normal Range 6.5 – 8.4
Source:.S. Ayers, D.W. Westcot, 1989/1994, 29 Rev.1, Water Quality For Agriculture, FAO Irrigation and Drainage Paper.
1 Adapted from University of California Committee of Consultants 1974.
2 ECw means electrical conductivity, a measure of the water salinity, reported in deciSiemens per metre at 25°C
(dS/m) or in units millimhos per centimetre (mmho/cm). Both are equiva-lent. TDS means total dissolved solids, reported in milligrams per litre (mg/l). 3 SAR means sodium adsorption ratio. SAR is sometimes reported by the symbol RNa. See Figure1 for the SAR
calculation procedure. At a given SAR, infiltration rate increases as watersalinity increases. Evaluate the potential infiltration problem by SAR as modified by ECw.Adapted from Rhoades 1977, and Oster and Schroer 1979. 4 For surface irrigation, most tree crops and woody plants are sensitive to sodium and chlor-ide; use the values
shown. Most annual crops are not sensitive; use the salinity tolerance tables (Tables 4 and 5). For chloride tolerance of selected fruit crops, see Table 14. With overhead sprinkler irrigation and low humidity (< 30 percent),
127
sodium and chloride may be absorbed through the leaves of sensitive crops. For crop sensitivity to absorption, see Tables 18, 19 and 20. 5 For boron tolerances, see Tables 16 and 17.
6 NO3 -N means nitrate nitrogen reported in terms of elemental nitrogen (NH4 -N and Organic-N should be
included when wastewater is being tested).
128
ANNEX 10: IRRIGATION WATER REQUIREMENTS
Irrigation water requirements – approach
A comprehensive study into the irrigation water requirements as part of the overall national
Water Resources Management Strategy was carried out by (MOP 1999-6). The method used
in this study is quoted in detail in the box below; it is the normal approach described in (FAO,
1977) and applied worldwide.
The crop irrigation water requirements consist of the potential crop evapotranspiration, ETp, minus the
effective rainfall, Pe.
The potential crop evapotranspiration, ETp, is the volume of water required to meet the crops’ potential
evapotranspiration during a specific time period, under a given cropping pattern and in a specific
climate. The ETp is based on the reference crop evapotranspiration, which can be calculated
according to the FAO Modified Penman Method or the Penman Monteith approach. Research at the
field station of the University of the West Indies reveals that the Penman Monteith approach performs
better under the local conditions prevailing in Trinidad and Tobago (Simon, 1995). In this report the
Penman Monteith approach will be used for the calculation of the reference crop evapotranspiration,
ETh.
To determine the potential crop evapotranspiration, ETp, the reference crop evapotranspiration value is
multiplied by a crop coefficient, kc. (see Section 4.2.2) Hence ETp = kc ETh.
Subsequently the crop irrigation water requirement is determined by reducing the calculated ETp value
by the effective part of the precipitation, Pe. The effective precipitation is that part of the total
precipitation on the cropped area, during a specific time period, which is available to meet
evapotranspiration in the cropped area.
Finally the Irrigation Water Requirements will be determined based on the efficiency of the irrigation
system. In an ‘average’ irrigation system more water is delivered from the water source than is
consumed (i.e. evapotranspired) by the irrigated crops. Most of the un-consumed part of the delivered
irrigation water returns to the groundwater or to the downstream surface water system.
To calculate the volume of irrigation water required to be delivered to the scheme, the crop irrigation
water requirements, ETp-Pe, is divided by the overall (or project) irrigation water-use ratio or efficiency
which quantifies the fraction of the irrigation water evapotranspired by the crops.
The consultants’ team of DHV used the CRIWAR simulation model to calculate the crop water
requirements (Bos et al, 1996).
In the study (MOP, 1999-6) the objective was to obtain values for national water resources
management evaluation. In this study a lot of interesting and useful work was done. Irrigation
requirements were calculated in the usual manner following the next four steps:
a. Calculate the ETh or reference evapotranspiration using the Penman Monteith formula,
based on average monthly values for temperature, humidity, wind and sunshine /
radiation (Piarco Airport record);
b. Select and apply the crop coefficients kc for the crop or crop mixture in the irrigation
scheme and calculate the crop evapotranspiration or ETp
c. Estimate the effective rainfall based on average monthly rainfall values
d. Estimate the irrigation efficiency
a. Reference Crop Evapotranspiration
129
Climatic data are measured at meteorological stations which are listed in Table 18.1.
Recordings, made by various departments, are collected by WRA and published in their
yearly Climatic Reports.
Table 18.1: Hydro-meteorological Stations
Name Number Measuring Agency Elevation (m)
Hollis Reservoir 2.3 WASA 152.4
Navet Reservoir 3.8 WASA 121.9
Penal Demonstration 7.7 WASA 12.2
Centeno 9.24 Ministry of Agriculture 15.2
UWI 9.6 UWI
WRA 9.63 Meteorological Department
Piarco Airport 9.32 Meteorological Department 11.0
Crown Point 15.1 Meteorological Department 7.6
Source: WRA Climatic Reports
The Hollis and Navet observation stations are located at the reservoir sites at higher
elevations. Since most of the irrigated areas are in the lowlands, these stations are of less
relevance for the determination of water demands for irrigated agriculture. The data obtained
at the Penal station have too many gaps (for the period 1975-1995 complete data sets are
only available for 7 years). The same counts for the observations at Centeno. The
observation stations at UWI and WRA were just recently started. Only the observation
stations at the Piarco and Crown Point Airports have long- term data available on humidity,
temperature, wind speed and sunshine hours. For this reason the Reference Crop
Evapotranspiration is determined based on the data from Piarco Airport (see Table 18.2).
Table 18.2: Reference Crop Evapotranspiration, data Piarco Airport (1975-1995)
Month Maximum
Temp
(oC)
Minimum
Temp
(oC)
Mean Rel.
Humidity
(%)
Mean Wind
velocity
(km/day)
Sunshine
hours
(h)
ETh
(mm/day)
January 29.6 20.4 78.6 112.9 7.69 3.8
February 30.4 20.5 74.4 128.4 8.08 4.4
March 31.2 21.1 70.8 151.1 7.80 4.9
April 31.8 21.8 69.8 150.9 7.69 5.0
May 31.6 22.7 73.4 151.1 7.43 4.8
June 30.7 22.9 78.5 128.8 5.99 4.1
July 30.9 22.8 80.0 108.9 6.45 4.1
August 31.2 22.9 81.8 90.0 6.49 4.1
September 31.7 22.6 79.9 89.5 6.47 4.2
October 31.5 22.6 79.1 86.7 6.33 3.9
November 30.8 22.2 79.7 87.6 6.42 3.6
December 30.1 21.4 76.6 98.2 6.72 3.5
Year 31.0 22.0 76.9 115.3 6.96 1531
Co-ordinates of Piarco Airport are10.37 N.L; 61.21 W.L
The number of climatic observation stations is small, and it is questionable whether they can
be considered representative of the whole country. Initiatives to address this situation have
already been taken by the Meteorological Department, which has recently installed five
telemetric stations (one at WRA).
130
b. Crop coefficients for the area
In most of the irrigated areas the main crop is vegetables, compromising a large variety of
vegetables, the main vegetables being cabbage, pumpkin, tomatoes, melongene (eggplant)
and cucumber (see Figure 18.1).
Figure 18.1: Green Vegetables Area cultivated in St George
Source: CSO, 1996
The crop coefficients (kc) are determined for the main stages of crop development (FAO,
1977):
Period 1: Initial growth (nursery);
Period 2: Crop development;
Period 3: Mid season;
Period 4: Late season
In areas without flooding during the wet season, vegetables can be grown on a continuous
basis throughout the year, with different planting dates and harvesting. For this situation an
overall crop coefficient (kc) can be adopted. The determination of the overall crop coefficient
is based on the kc values of the 5 main vegetables (see Table 4.4). If other vegetable crops
are added to this mix the effect on the overall kc will be so small it can be safely ignored.
Table 18.3: Overall Crop Coefficients (kc) for continuous vegetable growing
Stage crop
development
Crop
Period 1
(days)
kc
Period 2
(days)
kc
Period 3
(days)
kc
Period 4
(days)
kc
avg
kc
Cabbage 20 0.4 30 0.68 20 0.95 10 0.8 0.69
Pumpkin 30 0.4 40 0.68 45 0.95 30 0.6 0.69
Tomatoes 30 0.4 40 0.73 45 1.05 30 0.6 0.73
Melongene (eggplant) 30 0.4 45 0.68 40 0.95 20 0.8 0.72
Cucumber 25 0.4 35 0.65 50 0.9 20 0.7 0.71
Sources: MOP 1999-6 (using WS Atkins 1993, Agristudio 1994, FAO 1979, FAO 1977)
0,0
20,0
40,0
60,0
80,0
100,0
120,0
are
a (
ha)
vegetables
dry season
wet season
131
The average of the 5 weighted average kc values is used as the overall crop coefficient: 0.71;
the maximum is 0.73. While the (MOP 1999-6) study used the average vegetable kc of 0.71,
it is proposed to use the maximum value of 0.73 for the Felicity Pilot area.
If other crops, e.g. tubers, are irrigated, the resulting kc will be significantly different; this is
also true if large areas are used to cultivate one single (vegetable) crop.
c. Effective precipitation
To determine the effective precipitation several approaches can be used and each of these
approaches has its advantages and disadvantages. The (MOP, 1999-6) study used the
CRIWAR model for an approach which is generally applicable.
Effective precipitation is that part of the total precipitation that replaces, or potentially
reduces, a corresponding net quantity of required irrigation water. To calculate the effective
precipitation, the model uses a semi empirical method developed by the U.S. Department of
Agriculture. This method is combined in the model with an improved estimate of the effect of
the net irrigation application depth on effective precipitation.
Three major factors are considered to influence the effectiveness of precipitation:
1. Mean Cumulative Monthly Precipitation. In areas with light precipitation during the
growing season losses to deep percolation to the groundwater and surface run-off will
usually be low. Consequently the effectiveness of precipitation in areas with light
precipitation will be high.
2. Mean Cumulative Evapotranspiration. When the evapotranspiration rate is high, the soil
water will be rapidly depleted. As a consequence, a large amount of water can be stored
in the soil profile again before it reaches field capacity. Thus, the higher the
evapotranspiration rate, the higher the effectiveness of precipitation.
3. Irrigation application depth. For most irrigation areas, the depth of water application per
irrigation turn is assumed to equal the readily available soil water that can be stored in
the root zone. The capacity of the soil profile to store water for crop use depends on the
soil type and the effective rooting depth. A high storage capacity within the root zone
(which is equal to the application depth) indicates a relatively high effectiveness of
precipitation.
In CRIWAR, the effective precipitation is calculated on a monthly basis by an empirical
expression, which reads as follows:
Pe = f ( 1.253 P0.824
- 2.935 ) x 100.001ETp
where
Pe = effective precipitation per month (mm)
P = total precipitation per month (mm)
ETp = total crop evapotranspiration per month (mm)
f = a correction factor which depends on the irrigation application depth per turn
The factor f equals 1.0 if the irrigation water application depth (Da) is 75 mm per turn. For other
application depths, the value of f equals:
f = 0.133 + 0.201 ln Da if Da < 75 mm/turn
and
132
f = 0.946 + 7.3 x 10-4
x Da if Da > 75 mm/turn
If the use of these equations results in an effective precipitation that exceeds either ETp or P,
CRIWAR reduces the Pe value to the lowest of these two. When the mean total rainfall per
month is less than 12.5 mm, CRIWAR assumes all precipitation to be 100 per cent effective.
In the (MOP 1999-6) study average monthly rainfall data were used to determine the
effective precipitation. These results are useful for long-term water management planning at
the national level.
In the Felicity pilot study the requirement is different. The objective is to determine the crop
water requirements based on the farmers requirement. The farmer will not accept a yield
reduction every other year, which will happen if monthly averages are used to dimension the
system. In fact the farmer would like to see that there is always sufficient water. This may
prove uneconomical, however. A commonly accepted approach is to ensure that only once
every four or five years the water supply will not cover the entire irrigation water need and
crop yield reduction may occur. In other words, in 75%-80% of the cases the supply will be
adequate. This means that step c (calculate effective rainfall) needs to be different from the
approach of (MOP, 1999-6).
In this study a probability of 75% is assumed46; this means that only once every four years
the crop may show yield reduction from a limited supply of water. Rainfall data from
(MFPLMA, 2011) were used, see Table 4.9. The table also shows the rainfall adjusted for
2013, using the selected climate change outlook / trend for rainfall, see 13.2.5. The
difference is in the rainy season months, when the predicted decline in (average, monthly)
rainfall is 6.1 mm per decade.
Adjustment for local conditions
To use the Piarco rainfall data for the Felicity Pilot area a correction on the rainfall statistics is
made; a problem here is that only a yearly rainfall isohyetal map is available (Figure 18.2)
whereas there may be a different statistical relation for the dry season than for the wet
season. Another possible approach is to use the shorter time-series of two rainfall stations
operated by the Water Resources Agency at Flanagin Town and Mamoral. However, these
stations are a distance to the east, inland and on higher ground. For this reason a correction
using the isohyetal map of Trinidad (Figure 18.2) has been selected as the best approach
considering the available datasets, resulting in a 10% lower rainfall figure (2000mm/y vs
1600mm/y) to be applied for the months of the dry season.
The resulting effective rainfall for the Felicity Area is presented in Table 18.4 and Figure
18.3.
46 80% or 90% is also possible, but needs further statistical analysis of the rainfall dataset
133
Figure 18.2: Trinidad Isohyetal Map
Source: (WASA, 2008-21).
Table 18.4: Precipitation in mm (1971 – 2010)
Series 1971-2010 Adjusted 20133
month average 75% Flc1 Pe
2 75% Flc
1 Pe
January 75.4 31.7 28.5 15.1 31.7 28.5 15.1
February 48.1 24.0 21.6 11.6 24.0 21.6 11.6
March 37.3 14.1 12.7 6.9 14.1 12.7 6.9
April 54.8 14.7 13.2 7.2 14.7 13.2 7.2
May 116.1 51.0 45.9 24.9 51.0 45.9 24.9
June 240.7 177.6 159.8 71.4 167.2 141.1 61.1
July 254.0 201.1 181.0 80.0 190.7 162.3 69.8
August 259.4 201.0 180.9 79.8 190.6 162.2 69.6
September 189.7 154.1 138.7 63.1 143.7 120.0 52.9
October 209.3 135.9 122.3 56.2 125.5 103.6 45.9
November 233.0 176.2 158.6 68.6 165.8 139.9 58.3
December 157.0 101.6 91.4 42.6 91.2 72.7 32.3
Total 1874
Source: MFPLMA, 2011 (average and 75%); own calculations 1 Adjusted for difference between Piarco and Felicity using isohyet map;
2 Calculated using CRIWAS (3.0).
3 Corrected for trend in climate change to 2013 of 6.1 mm decrease per decade (Chapter 9.2). The 75% rainfall is about 74%
lower than the average rainfall, so the rainfall figures for 1971-2010 were adjusted by subtracting 10.4 mm (28 year x 0.61mm
x 74%) from both the 75% rainfall and the 75% effective rainfall monthly figures47
.
47
This is based on the assumption that the recommended trend based on the selected climate change scenario
(see Chapter ....) started already in 1971, the start of the rainfall data series used in this study. However, in :
134
Figure 18.3: Effective Rainfall Felicity Area for 2013 and 2050
Use of decade data
One more way to improve accuracy is to use decade (10 day) data for both the determination
of the Reference Crop Evapotranspiration and for the effective precipitation. While this is
recommended when designing rotation schedules for irrigation management, this level of
accuracy is not generally used for design purposes. Also, the assumptions related to the
cropping pattern and planting dates need to be known much more accurately. It is not clear if
such levels of irrigation management are required or desirable within the Trinidad context.
d. Irrigation Efficiency
Irrigation efficiency is defined as the ratio between the net and gross irrigation requirements.
Once the crop irrigation water requirements (net) have been determined, the irrigation
requirements (gross) can be obtained by taking into consideration conveyance losses
(including seepage and evaporation), distribution (or operational) losses and field losses
(including losses due to deep percolation through the root zone to groundwater and field
runoff)48.
Return flow, closed loop system
Irrigation efficiencies can be established for various levels, such as the field, system, or
regional (river basin) level. This distinction is important for water resources development
studies, where drainage losses from one system may add to the available supplies for other
downstream users (re-use of drainage water). Regional efficiencies can be much higher than
efficiencies for individual irrigation schemes. An example is the irrigated system of the Nile
Delta in Egypt. The overall system efficiency in the delta is about 90 per cent, although the
efficiency of individual schemes can be as low as 50 per cent. This phenomenon of re-use is
taken into account in the (MOP, 1999-6) study. The return flow is defined as the percentage
of the gross irrigation requirements which will return to the surface water system. For most
MFPLMA, 2011 the trend for average yearly rainfall data appears to be flat. If the correction is not applied this will result in a significant reduction (10%) of the calculated water requirement. 48
A detailed study on irrigation efficiency is recommended to establish the irrigation losses / efficiency based on the local situation and conditions. Another approach is to actually consider the Felicity area as a pilot and to monitor the actual losses; this knowledge can then be adapted and applied to other areas in Trinidad.
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
0 1 2 3 4 5 6 7 8 9 10 11 12
eff
ect
ive
rai
nfa
ll (m
m/m
on
th)
month
effective rainfall Pe
Pe 2013
Pe 2050
135
schemes a return percentage of 30 per cent is used, for sprinkler irrigation and the relatively
efficient irrigation at the former Caroni (1975) Ltd Rice Farm lands a value of 20 per cent is
used. This means that it is assumed that in most of the areas 30 per cent of the gross
irrigation requirement will return to the system.
There is a serious downside to this approach: salinisation. This strongly depends on the
water quality, and although initially it may seem to be a benign problem, in the end it requires
specific measures: e.g. expansive drainage systems have been built in Iraq, Pakistan, Egypt,
and large parts of Central Asia with the sole purpose of salinity control / land reclamation; in
parts of the Unites States drainage is no longer allowed for reasons of saline effluent,
effectively rendering irrigation impossible.
For the design of a single irrigation scheme the return flow cannot be taken into
consideration, unless the return flow is re-used again by pumping it back to the inlet of the
scheme and mixing it with the ‘fresh’ irrigation water supply. This method, also known locally
as ‘closed loop re-use’ and applied on a pilot scale on a farm close to the Felicity pilot area49,
will be considered as an option for the full Felicity area with the selected approach (see
Chapter 14). For now the closed loop re-use is seen as an option to reduce the total
requirement of irrigation water. In the design options it is considered as an alternate,
additional water resource, to be added to reach the overall irrigation water requirement
estimated in this chapter.
Irrigation efficiencies for rice, vegetable cultivation and citrus are discussed below.
Rice
The only irrigated area with double rice cropping is at the Rice Farm managed by Caroni
(1975) Ltd., which is located in the lower part of the Caroni basin. Irrigation water for this
farm is pumped from different streams. The rice is grown on heavy clay soils (with restricted
internal drainage), which can be assumed to have small infiltration losses (low infiltration
rates, low deep percolation losses). Adjacent to the Rice Farm is the Caroni swamp,
percolation losses to the swamp are most probably not high (high groundwater table). Given
this situation an overall irrigation efficiency of 65 per cent is assumed for the Rice Farm:
about 20 % is lost in the conveyance system and another 20 per cent is lost during the field
application (so irrigation efficiency is 0.8 x 0.8).
Vegetables
Vegetables are generally grown on beds. To irrigate the crops ‘spray pipes’ or ‘spray hoses’
are now widely applied, mostly replacing the older ‘furrow-splash’ method. These flexible pvc
pipes are rolled out in the field and stay there until they need to be replaced or until tilling
takes place. The spray pipes deliver water to the crops directly and by filling the furrows in
between, acting as miniature sprinklers. They are connected with rigid pvc pipes through
couplings; the rigid pipe delivers the water to the field. Only low pressure is needed, saving
construction costs and energy. See box below and the pictures in Figure 18.4 and Figure
18.5.
49
The farm, known as Mr. Roop’s Farm, is run on a basis of environmentally friendly and holistic farming. In fact, the term ‘closed loop’ is misleading, in fact this 3-acre plot can better be termed ‘self-contained’. While the full concept will be difficult to replicate on a wider basis, aspects of his approach can be applied. The regulation that tree crops are not allowed in the Felicity Area also precludes successful adoption of main elements of Mr. Roop’s farming system.
136
Box: commercial supplier praising the advantages of spray pipes
1. It is a water-saving system for spraying irrigation water that requires only low
water pressure, which really helps save electricity and water.
2. It sprays evenly. This helps improve the germination rate of seeds and the
survival rate of seedlings.
3. It has two functions: One is it sprays evenly. The other is to inject the liquid
fertilizer into the tube, mix with the water. This helps establish the evenness of
topdressing.
4. After using solid fertilizer, the spraying irrigation helps dissolve fertilize effectively
seep into the soil and easily reach the root zone without washing out.
5. It helps maintain the looseness of soil (note: important according to Trinidad
farmers).
6. The crops are planted in rows which are extremely suitable for using our spray
tubes which spray can cover a width of 7 meter.
7. It is the most suitable equipment for irrigating sandy soil
8. Spraying irrigation in late afternoon reduces the survival rate of moths and other
harmful insects, and thus reduces the amount of pesticide that is required
In addition: it is readily available in Trinidad, accepted and used by the farmers,
and economical – the price of the tubes were not seen as a problem.
137
Figure 18.4: Spray pipes / tube – fitting and pipes in vegetable field in Felicity area.
Figure 18.5: Spray pipes / tubes application in a vegetable field (China)
The use of overhead sprinkler systems is discouraged in Trinidad, because of relatively high
water losses. “Evaporation losses from the spray are small and generally below 2 percent.
Losses due to wind drift may be considerable at higher wind speeds and can reach 15% at
5m/s. Strong winds also result in a poor water distribution pattern. Overhead sprinkler
irrigation should not normally be used when wind speeds are higher than 5m/s” (FAO,
1977p64). Farmers in Trinidad also mention the labour intensity of overhead sprinkler
systems as these typically have to be moved every few hours.
In the dry season irrigation is applied every 2-3 days. In some areas water is pumped directly
from the streams, and in other areas a conveyance system (e.g. Aranguez) is used.
Vegetables are usually grown on well drained soils, which suggest that percolation losses
may be higher. On the other hand operational losses might be smaller since the irrigation
technique described above is efficient, and losses will only occur in the furrows around the
beds and in the conveyance system to the fields. The overall efficiency is assessed at 67 per
138
cent: assuming a field application (tertiary) efficiency of about 75 per cent and a conveyance
(secondary) efficiency of about 90 per cent.
For the Felicity area, assuming that spray pipes will be applied, the overall scheme efficiency
is estimated at 65-70%, while the on-farm application efficiency is estimated at 75%.This is
not taking into account any losses in the conveyance system from the source of the irrigation
water to the Felicity Pilot Scheme intake; these will depend on the conveyance option that is
selected and implemented.
e. Additional considerations
Local rainfall figures are not used because the time series are not long enough. In the future
these local rainfall figures may be used as input.
Local meteorological data are not used. For now the only reliable long-term dataset for non-
rainfall meteorological data is available from the Piarco Airport Meteorological Station only.
As this is not very far (relatively) and at roughly the same elevation as the Felicity Pilot site,
this assumption is considered acceptable.
Wind can vary greatly at short distances, being influenced by the elevation of land and wind
shielding by large crops, trees and bushes, as well as by build-up areas. As detailed
information is not available at the time of this study and as this is mostly useful in determining
localized irrigation schedules, the effect of wind variability is ignored.
Local variability in effective rainfall and evapo-transpiration: these are often caused by local
variations in wind, see above.
Soil differences translate into different rates of infiltration, which can strongly influence field
application efficiencies. As the preferred method of irrigation is the use of spray pipes and as
the soils of the Felicity Pilot area are relatively heavy (50% clay, 50% sand/silt mix), while the
typical irrigation gift is relatively small, it can safely be assumed that deep percolation losses
are limited and soil differences do not translate into large infiltration differences.
Supplemental irrigation: In fact all irrigation in Trinidad can be described as ‘supplemental
irrigation’ as even in the dry season there is a contribution from rainfall. However, the term is
often associated with irrigation during the rainy season. The availability of irrigation water will
give extra security for the farmers to plant at dates that are more optimal, related to expected
harvest dates and prices; it also reduces the probability of crop yield reduction if the ‘petite
careme’ dry interval during the rainy season (end of September, early October, typically 15-
18 days) is particularly dry and pronounced. Interestingly the calculations based on the 75%
effective rainfall show that even in the rainy season there is a clear need for irrigation, a need
that gets more pronounced if climate change outlooks are considered (see 13.2.4 and
13.2.5).
Variability in crop factors: In Table 18.3 crop coefficients are given. In fact the crop
coefficients depend on variety, planting date, local and micro-climate, and also on the
availability of other growth factors such as sunlight, fertility, temperature and soil. Pests and
diseases can radically reduce crop development, lowering ETh. For the calculation of the
irrigation water requirement it is assumed that crop growth is unimpeded and all
circumstances are optimal.
Soil salinity: ETh can be affected by soil salinity since the soil water uptake by the plant can
be drastically reduced due to higher osmotic potential of the saline groundwater. Poor crop
139
growth may be due to adverse physical characteristics of some saline soils. Some salts
cause toxicity and affect growth. The relative extent to which each of these factors affects
ETh cannot be distinguished (FAO, 1977). For the Felicity Pilot area we will not consider soil
salinity in the calculation of ETh.
In Trinidad and at the Felicity Pilot area location the average yearly rainfall exceeds the
average yearly evaporation. If there is any accumulation of salt during the dry season
irrigation it can be assumed that this is leached out during the rainy season. An adequate
drainage system needs to be in place to ensure the proper evacuation of the leaching and
normal drainage water. The decrease of overall rainfall due to climate change may have to
be considered, and the increase in salinity during (relatively) dry years should be monitored.
Crop yield reduction: while the calculations are done for a crop that is fully supplied with all
inputs and water, the effect of a (temporary) reduction in the availability of water in the root
zone on crop yield is very dependent on the stage of crop growth. Crops are very sensitive to
water stress during specific growth stages, such as germination and establishment, flowering
and seed development. Conversely, during the crop ripening stage and often during the
vegetative stage a temporary lack of water will result in a delay in growth, or in a small
overall yield reduction. For some crops the reduction of the water application in the
harvesting stage has a positive effect on the quality (FA), 1977).
Crop selection / cropping pattern: It is obvious that the actual cropping pattern in the Felicity
Pilot area will determine the crop water requirements. As the cropping pattern is free
(restrictions are on tree crops only) an overall estimate of the ETh is the only practical way to
design the irrigation system. However, with the assumptions made and the use of the highest
of the average vegetable kc values there is enough flexibility to adopt other crops, too. Crops
that require very high amounts of irrigation water, such as rice and aquaculture, may not be
possible (and should be prohibited) in the Felicity Pilot area.
Drought resistant crops: In the Trinidad context, with a relatively short dry season in which
still significant rainfall occurs, the combination of drought resistant crops and irrigation is not
practical or economical. If irrigation water is relatively scarce crops that can withstand brief
periods of water stress without significant yield reduction can be selected. In general the
investment for irrigation infrastructure, both at scheme level and on the field, will only be
justified if relatively high-value crops can be grown. In general drought-resistant crops are
also lower value and lower yielding. Efforts at regional crop research centres to develop high-
yield high value crops that can handle water stress better should be closely watched;
promising crops should be tested in Trinidad and then promoted by the Ministry of Food
Production – extension service.
140
ANNEX 10: DESIGN
141
1. SCENARIOS WATER SOURCE FELICITY
Following discussions in the week of 02-06 September between the design team and the
consultants the possible scenario’s had to be revisited, mainly due to better understanding of
costs. The main costs appear to be pumps with high discharges and the pipeline to convey
the water from the RSSP to Felicity.
Unfortunately an estimate of the benefits for the introduction of irrigation at Felicity is not
available due to the limited time available and ambitious planning for the project.
The infrastructure within the Felicity area, to convey the water from the primary source to the
various blocks (laterals / secondary), and the offtakes to the ponds (tertiary) remain the same
regardless of the selected water resource option. This has been elaborated and the costs
have been estimated using the best available unit costs.
The use of on-farm ponds of standard dimensions (20x20 m, 4 m effective depth) was also
part of the standard lay-out. Smaller ponds have been proposed and are now used in the
design50. The dimensions of the smaller ponds are 17.5x17.5, without embankment (or only a
small rise to prevent unwanted drainage and siltation.
1.1 Scenario 1: Pipeline from RSSP to Felicity.
Availability of water is sufficient, at least for now; the RSSP (Ravine Sable Sand Pits) will act
as buffer during both the dry and rainy season. A relatively low maximum flow (200l/s) is
needed.
Requirements:
- Regulator to divert water from Caparo River into RSSP (part of Caparo River Basin Study
recommendations for flood mitigation – not costed in Felicity project)
- Submersible pump at RSSP, head +20m, intake protection – stilling well, pump house,
generator or electrical mains. Capacity /design flow in dry season is 170 l/s. Operation
24/7 (during peak demand). Detailed design will only be possible once a decision on the
implementation of the RSSP is made, which may be several years in the future. A study
should be made on the feasibility of a pump on a floating raft; the intake will then always
be at the optimum level, siltation will not be a problem, and any type of pump can be
used, as suction head is not a problem. The joints to allow free floating of the platform
should be designed with care.
- Pipeline to connect RSSP with Felicity head works. HDPE, Ø600mm, 11.5 km (along old
railway, Caparo River to Honda bifurcation, Honda River, Caparo River
- (Booster) pump to pressurise the secondary pipe system again
50
Based on decisions made during a final Design meeting on 09/09/2013
142
Figure 1.1: Alignment of the RSSP to Felicity pipeline
Considerations:
- The pipe will be expensive
- A booster pump at the head of the distribution system is needed, or the pump (into the
pipe) has to be dimensioned to facilitate flow over 11.5 km with 20 m + the initial pump
pressure; without these interventions there is not enough to pressure in the Felicity
secondary system.
1.2 Scenario 2: Using the Caparo River from the RSSP to Felicity
This scenario was thought to be second choice for reasons of water loss and water quality
issues, and especially because of expected large pump capacity, to take advantage of very
brief and high peaks in the river. However, as the pipeline option may be rather expensive
the consultants revisited some of the assumptions.
The core of this option is using the Large Buffer Ponds which are reserved in the lay-out of
the Felicity area. These ponds cover an area of 23.6 hectares; net area is perhaps 25% less,
at 18 ha. If a live storage depth of 4 meters is realised, they can hold 0.72 Mm3. This can be
pushed with a live storage of 4.5m (and higher embankments) to 0.81 Mm3. The ponds are to
be interconnected to allow for more flexible and efficient use of the water stored, and to
optimise the combined storage of the ponds. A detailed calculation of volume and
dimensions is given in the discussion on Phase 1, in Table 1.4.
Requirements:
- RSSP for buffering in both the dry and rainy season
- Regulator to divert water from Caparo River into RSSP (part of Caparo River Basin
Study recommendations for flood mitigation – not costed in Felicity project)
- Submersible pump at RSSP, head +20m, intake protection – stilling well, pump house,
generator or electrical mains. Capacity /design flow in dry season is 5x180=900 l/s.
(considering 10% losses and no water theft). Operation during 2 days continuously out
of 10 during peak demand time (week 1-24).
- Pump into the Caparo River at RSSP location
- Divert from Honda River to Chandernagore River (20% of flow); a diversion work is
required;
143
- Pump at Chandernagore River (one pump, capacity 1x170 l/s). Pump into the 2 Large
Buffer Ponds (LBPs) LLBP 3 and LLBP 4.
- Pump at Caparo River (four pumps, capacity 1x170 l/s). Pump into the Large Buffer
Ponds (LBPs) R1, R2 and R3 and LBP L1, L2, L3 and L4.
Interconnecting pipes between the LBPs (between L1-L4, and R1-R3, and LLBP3 and 4), to
allow for flow in both ways. Considerations:
- The design of the main pipe distribution system in the Felicity Area should allow
interconnection between the ponds and 5 pumps using large pipes, to minimise head
losses and head differences over the system, regardless of which pump supplies the
main;
- When there is water in the river(s) all pumps should run to fill the ponds, one of them to
fill / pressurise the main pipe system of Felicity. Each of the pumps may be used for this.
- All pumps at the LBPs can be used
o to pump from the river into the Felicity distribution system (Z = 6m, P = 50 m, Δh =
10-15 m))
o to pump from the river into the LBPs (Z = 3 m, Δh = 10-15m)
o to pump from the LBPs into the Felicity distribution system (Z=<1m, Δh = 5-10 m, P
= 50m)
- The pumps should be standardized in order to deliver the required flow and head into
the Felicity distribution system
- Sets of ponds (on both sides of the Caparo River) will be serviced by one pump
- Pumps will be situated on the river, raised (1 meter) to safeguard them from flooding
- An oblique weir will be installed at the pump site, to create a buffer while still allowing
large volumes of water to pass during a flood. The weir will contain connector pipe/pipes
if two ponds on different sides of the river are to be serviced by one pump.
- A standard design for the oblique weir can be adapted to the required dimensions. The
dimensions of the Caparo River are not known to the consultants at this stage. Design
instructions are available in http://content.alterra.wur.nl/Internet/webdocs/ilri-
publicaties/publicaties/Pub20/pub20-h.annex3.pdf.
1.3 Option with Scenario 2
- Setting up / increasing the water level in the Caparo River and creating a larger buffer
- Use earth from the cut of the LBPs to build an embankment along the Caparo River
- Increase the level of the oblique weirs
- Increase the cross-section of the Caparo River to ensure sufficient capacity during floods
- Drain outfalls into the Caparo River need to be fitted with flap / no-return gates
- Ensure that the bridges / roads will not be flooded.
1.4 Closed loop – drainage re-use
While the disadvantages of the closed loop system (as asked for in the Terms of Reference)
are made clear at several locations in this report, the simplest way to realise ‘closed loop re-
use’ is to pump water from the Caparo River at the last bridge of the Felicity Area. A cross-
weir is proposed here to facilitate Phase 1 (see following text). With the pump that fills the
LBPs drainage water can (and will be, in Phase 1) be re-introduced into the system.
If a cleaning/treatment phase is to be included a reed bed is proposed. However, this takes
up land, and the water has to be pumped into the reed bed, and out of it again, into the LBP.
144
Use of drainage water introduces (increased) risks of soil salinisation. Leaching of the soil
needs to take place at least once each season, preferably during the rainy season, and the
saline drainage water has to be evacuated from the Felicity area.
1.5 Phase 1: Develop 20% of the Felicity site first
Because water availability is a constraint (any work on the RSSP and works to deliver water
from the RSSP to Felicity will take more than one and possibly several years to complete)
the consultants propose to start with a ‘pilot in a pilot’. An area of 20% of the full project area
has been selected based on the following criteria:
- Abutting the Caparo River
- Sufficient area for Large Buffer Ponds
- On-farm ponds already installed in a relatively large proportion of plots
- Access to be relatively easy
Based on the above criteria the north-west corner of the Felicity project area was selected,
encompassing parts of both Felicity 1 (plots 1-77, two plot numbers missing) and Felicity 2
(plots 1-60), for a total of 135 plots, or almost exactly 20% of the 653 plots of the Felicity
project area.
1.5.1 On-farm ponds
On-farm ponds are used in the south of Trinidad to enable limited irrigated agriculture in the
dry season, and have been adopted by the Ministry of Food Production. If implemented
properly they can store a significant amount of water, but not enough to last the full dry
season in the Felicity Area. Considerations on the on-farm ponds:
- Construction appears to be somewhat expensive at TT$ 30,000 each (very roughly
costed at TT$ 20 per m3 cut).
- The buffer function of the on-farm ponds is essential to make the design and operation
flexible. Without the ponds the capacities for the distribution system and the pumps need
to be significantly larger (and more expensive) because of the fluctuations in demand for
water. With the ponds a constant delivery of water can be achieved. Monitoring of water
use is also easier.
- The required size of the ponds is open for discussion; in fact smaller ponds will also work,
as long as they can store at least 2 weeks of water demand in the dry season (ensuring
water availability). In the design we worked with a net volume of 1600 m3. In discussions
we understood that this may be (significantly) lower.
- The design needs to be optimised to store as much water as possible on as small a
footprint as possible. The current design has low embankments around the pond, which
take additional land without increasing the storage by much. A pond without
embankments takes much less land and can also benefit from local drainage into the
pond. Flooding should be prevented by creating an overflow / spill into the drains.
- Smaller sized ponds mean reductions in the tertiary lines, but also mean that the ‘refill’ of
the pond has to be more frequent. 2 weeks return time is considered the practical lower
limit for operation.
- This means that on-farm ponds with a capacity of about 600 m3 may be sufficient. A
different design can be made to accommodate that amount of water. Losses due to
evaporation and leakage will be lower. It is recommended to look at experiences with
storage of water used in greenhouses – intensive horticulture in the Netherlands is
145
obliged to recycle water and buffer rainwater, and land is very scarce in these areas.
Lining there is done using sturdy geo-textiles/plastics.
- In the design a pond is considered to be constructed in cut only, 4 m deep, to be filled up
to 3.5 meter. Side slopes are assumed at 1:151. The average area of the pond can then
be kept at 172 m2. Overall area will be 17.5x17.5 m or a little below 4% of the plot size52.
- Smaller on-farm ponds mean larger Large Buffer Ponds. With the on-farm ponds reduced
to one-third of the volume (0.39 M m3) a LBP storage of about 0.61 M m3 is required. This
is possible on the reserved land within the Felicity project area and can be fitted in the
proposed design. In this annex calculations are shown which will enable Phase 1; the
calculated storage for Phase 1 is different as the full dry season requirement needs to be
buffered in this pilot phase.
- On-farm ponds take away land, not just in the dry season but also in the rainy season.
This has to be taken into consideration too. If a pond takes away 4% of the land this
means that during the rainy season 4% of the land cannot be used, which otherwise
would yield a crop. Thus the net ‘gain’ of irrigated land during the dry season is only
(100%-7/5*pond area percentage-pond area percentage). For 4% the effective loss is a
little less than 10% of dry season acreage. If the area of the pond is higher this factor is
also higher.
The operation of a system with smaller ponds as described above means that the operation
of the system gets much more intensive. Filling of the ponds will have to be scheduled up to
3 times as often, meaning that up to 3 times as many valves need to be opened on one
single day. Also, the buffering is much less, so flows into the ponds will be higher, as the
drawdown during the dry season in the on-farm ponds is much less. This will be buffered by
extra capacity in the LBPs (Phase 1 design), so the dimensioning of the primary system will
not change. The secondary system needs to be dimensioned to manage these higher
maximum flows (up to 210 l/s for the secondary system). For a simulated operation of a small
on-field pond see Figure 1.2 and Figure 1.2
51
A solution for the reported erosion needs to be found – experience indicated that lining the sides by smearing with mud will reduce leakage and stabilise the sides. This was explained during the field visit to Mr. Roop’s Farm (Mr. Ramgopaul Roop, [email protected]), on 23 August 2013. 52
Actually on average 13.1 m, if square, with an additional 2x2.25m to account for the slope.
146
Figure 1.2: Simulated operation of a small pond – example - 2013
Figure 1.2: Simulated operation of a small pond – example - 2050
1.5.2 Design of Large Buffer Ponds
To compensate for the flow (at secondary level) of 32.9 l/s over 5 months (20% of 162 l/s), a
volume of 0.427 Mm3 needs to be stored / available; if smaller ponds are implemented the
volume will be 0.557 Mm3.
0
500
1000
1500
2000
2500
3000
3500
4000
0 5 10 15 20 25 30 35 40 45 50
Po
nd
leve
l mm
week
Pond level - 2013
depth ponds refill
dry season 18000 mm filltotal 30519 mm fill
0
500
1000
1500
2000
2500
3000
3500
4000
0 5 10 15 20 25 30 35 40 45 50
Po
nd
leve
l mm
week
Pond level - 2050
depth ponds refill
dry season 19000 mm filltotal 36832 mm fill
147
Table 1.1: Large Buffer Ponds in Felicity Area – reserved area
Area (ha) perimeter (m) Area (ha) perimeter (m)
LBP L1 2.584 989 LBP R2 2.882 845
LBP L2 1.298 498 LBP R3 1.857 657
LBP L3 2.176 733 LBP LL3 1.912 601
LBP L4 3.676 793 LBP LL4 4.721 1013
LBP R1 2.545 707 total area 23.651 6836
Close to or adjacent to the ‘Felicity Pilot’ there are 4 reservations for Large Buffer / Retention
Ponds. Naming them from upstream to downstream along the Caparo River these are the
ponds indicated in blue in Table 19.1. These ponds will have a total (gross) area of about
10.7 ha.
However, the area that the embankments take in has to be considered. It is proposed to
make the LBPs with cut & fill, to create embankments from part of the cut. A typical
embankment design is shown in Figure 19.2. Considerations are given in Table 19.2.
Figure 1.3: Typical Large Buffer Pond embankment / design
Table 1.2: Dimensions of Large Buffer Pond Embankment
width area
top width 1.50 1.50 4.50
height 3.00
outside slope 1: 1.50 4.50 6.75
inside slope 1: 1.00 3.00 4.50
bottom width 9.00 15.75
Calculations show that the area of the embankment takes away a significant amount of land,
which has to be compensated by deepening the pond. A maximum height of the
embankment of 3 meter is assumed, with 0.5 meter of freeboard. At maximum storage the
water will be at 2.5 m above ground level.
Pond losses (sum of rainfall, evaporation and leakage losses, 1:4 year) over the months of
January until and including May (week 22) are 670 mm.
Eight different options have been calculated:
1. No extra area, no compensation for evaporation. It is assumed that the evaporation
during the dry season can be compensated by pumping the scarce flow peaks during
the dry season from the Caparo. The resulting pond area will be cut to the depth that
outside slope 2:3
bottom width 9 m
top width 1.5 m
inside slope 1:1
height 3 m
148
allows for storage of the volume of irrigation water for the 135 ponds in Phase 1.See
Table 1.9 and Table 1.10.
2. No extra area, compensation for evaporation. In this scenario the evaporation losses
are compensated by increasing the storage depth. The resulting pond area will be cut
to the depth that allows for storage of the volume of irrigation water for the 135 ponds
in Phase 1. See Table 1.5 and Table 1.6.
3. Extra area by adding ponds no. 74, 75 and 76 to LBP R3, no compensation for
evaporation (see Table 19.5). It is assumed that the evaporation during the dry
season can be compensated by pumping the scarce flow peaks during the dry
season from the Caparo. The resulting pond area will be cut to the depth that allows
for storage of the volume of irrigation water for the 135 ponds in Phase 1. Extra area
will be added to decrease the required cut. See Table 1.11 and Table 1.12
4. Extra area by adding ponds no. 74, 75 and 76 to LBP R3, compensation for
evaporation. As 3, but with compensation for pond losses.Table 1.7 and Table 1.8.
For each of these options a further option was considered: using smaller on-field ponds. This
means that a total of 8 possibilities were calculated and evaluated. An overview of the results
of the calculations is shown in Table 1.4.
Table 1.3: Add 3 plots to LBP R3
perimeter Area Phase 1
(m) (ha)
LBP L3 733 2.18
LBP L4 793 3.68
LBP R2 845 2.88
LBP R3 657 1.86
LBP R3 additional 307 2.44
total 7143 13.03
Without more accurate prices for earthworks and compacting it is not possible to do an
accurate estimate. However, as an indication the amount of cut has been calculated and an
indicative price of TT$ 30 per m3 has been applied, to cover all cut / fill and transport of
various volumes.
During a final meeting on 9/9/2013 decisions were made on:
- The application of smaller ponds
- The compensation of pond losses
- The possibility of using additional area (adding plots to the LBP area)
This means that Table 1.8 shows the estimated amounts of earthworks and the estimated
cost for constructing the LBPs for Phase 1.
Table 1.4: overview of different options – estimated cost for earthworks
cost est. (M TT$) depth cut (m)
on-farm ponds 1600 m3 600 m3 1600 m3 600 m3
pond losses not counted no extra plots 6.9 10.9 2.8 4.5
compensate pond losses no extra plots 8.6 12.4 3.5 5.1
pond losses not counted extra plots 5.5 9.3 1.8 3.0
compensate pond losses extra plots 7.4 11.3 2.4 3.7
149
Table 1.5: Pond losses compensated, no extra plots, ‘normal’ ponds
Table 1.6: Pond losses compensated, no extra plots, small ponds
Table 1.7: Pond losses compensated, extra plots, ‘normal’ ponds
Table 1.8: Pond losses compensated, extra plots, small ponds – PREFERRED OPTION
Calculation embankment width area Unit cost Total
(m) (m) (m2) (TT/m3) (M TT/m3)
top width 1.50 1.50 4.50 cut/fil l 44.9 30 1.3
height 3.00 compacting 44.9 0 0.0
outside slope 1: 1.50 4.50 6.75 cut/remove 220.1 30 6.6
inside slope 1: 1.00 3.00 4.50 topsoil 21.2 30 0.6
bottom width 9.00 15.75 topsoil transport 21.2 0 0.0
topsoil removal 0.20 m realised volume 427.9
depth below level 3.50 m required volume 426.9
LBP R3 additional 0 cost estimate M TT$ 8.6 8.6
Pond losses dry season 0.67 m unit cost 1m3 TT$ 30.0
1=yes 0=no
(1000 m3)
Earthworks volumes
Calculation embankment width area Unit cost Total
(m) (m) (m2) (TT/m3) (M TT/m3)
top width 1.50 1.50 4.50 cut/fil l 44.9 30 1.3
height 3.00 compacting 44.9 0 0.0
outside slope 1: 1.50 4.50 6.75 cut/remove 348.6 30 10.5
inside slope 1: 1.00 3.00 4.50 topsoil 21.2 30 0.6
bottom width 9.00 15.75 topsoil transport 21.2 0 0.0
topsoil removal 0.20 m realised volume 556.3
depth below level 5.10 m required volume 556.9
LBP R3 additional 0 cost estimate M TT$ 12.4 12.4
Pond losses dry season 0.67 m unit cost 1m3 TT$ 30.0
1=yes 0=no
(1000 m3)
Earthworks volumes
Calculation embankment width area Unit cost Total
(m) (m) (m2) (TT/m3) (M TT/m3)
top width 1.50 1.50 4.50 cut/fil l 49.7 30 1.5
height 3.00 compacting 49.7 0 0.0
outside slope 1: 1.50 4.50 6.75 cut/remove 169.4 30 5.1
inside slope 1: 1.00 3.00 4.50 topsoil 26.1 30 0.8
bottom width 9.00 15.75 topsoil transport 26.1 0 0.0
topsoil removal 0.20 m realised volume 425.9
depth below level 2.35 m required volume 426.9
LBP R3 additional 1 cost estimate M TT$ 7.4 7.4
Pond losses dry season 0.67 m unit cost 1m3 TT$ 30.0
1=yes 0=no
(1000 m3)
Earthworks volumes
Calculation embankment width area Unit cost Total
(m) (m) (m2) (TT/m3) (M TT/m3)
top width 1.50 1.50 4.50 cut/fil l 49.7 30 1.5
height 3.00 compacting 49.7 0 0.0
outside slope 1: 1.50 4.50 6.75 cut/remove 306.9 30 9.2
inside slope 1: 1.00 3.00 4.50 topsoil 26.1 30 0.8
bottom width 9.00 15.75 topsoil transport 26.1 0 0.0
topsoil removal 0.20 m realised volume 563.5
depth below level 3.70 m required volume 556.9
LBP R3 additional 1 cost estimate M TT$ 11.5 11.5
Pond losses dry season 0.67 m unit cost 1m3 TT$ 30.0
1=yes 0=no
(1000 m3)
Earthworks volumes
150
Table 1.9: Pond losses not compensated, no extra plots, ‘normal’ ponds
Table 1.10: Pond losses not compensated, no extra plots, small ponds
Table 1.11: Pond losses not compensated, extra plots, ‘normal’ ponds
Table 1.12: Pond losses not compensated, extra plots, small ponds
An alternative that has not been calculated is: not to increase the area of the LBPs but to
decrease the area of the irrigated land.
Calculation embankment width area Unit cost Total
(m) (m) (m2) (TT/m3) (M TT/m3)
top width 1.50 1.50 4.50 cut/fil l 44.9 30 1.3
height 3.00 compacting 44.9 0 0.0
outside slope 1: 1.50 4.50 6.75 cut/remove 163.9 30 4.9
inside slope 1: 1.00 3.00 4.50 topsoil 21.2 30 0.6
bottom width 9.00 15.75 topsoil transport 21.2 0 0.0
topsoil removal 0.20 m realised volume 425.5
depth below level 2.80 m required volume 426.9
LBP R3 additional 0 cost estimate M TT$ 6.9 6.9
Pond losses dry season 0 m unit cost 1m3 TT$ 30.0
1=yes 0=no
(1000 m3)
Earthworks volumes
Calculation embankment width area Unit cost Total
(m) (m) (m2) (TT/m3) (M TT/m3)
top width 1.50 1.50 4.50 cut/fil l 44.9 30 1.3
height 3.00 compacting 44.9 0 0.0
outside slope 1: 1.50 4.50 6.75 cut/remove 300.4 30 9.0
inside slope 1: 1.00 3.00 4.50 topsoil 21.2 30 0.6
bottom width 9.00 15.75 topsoil transport 21.2 0 0.0
topsoil removal 0.20 m realised volume 561.9
depth below level 4.50 m required volume 556.9
LBP R3 additional 0 cost estimate M TT$ 11.0 11.0
Pond losses dry season 0 m unit cost 1m3 TT$ 30.0
1=yes 0=no
(1000 m3)
Earthworks volumes
Calculation embankment width area Unit cost Total
(m) (m) (m2) (TT/m3) (M TT/m3)
top width 1.50 1.50 4.50 cut/fil l 49.7 30 1.5
height 3.00 compacting 49.7 0 0.0
outside slope 1: 1.50 4.50 6.75 cut/remove 113.3 30 3.4
inside slope 1: 1.00 3.00 4.50 topsoil 26.1 30 0.8
bottom width 9.00 15.75 topsoil transport 26.1 0 0.0
topsoil removal 0.20 m realised volume 438.1
depth below level 1.80 m required volume 426.9
LBP R3 additional 1 cost estimate M TT$ 5.7 5.7
Pond losses dry season 0 m unit cost 1m3 TT$ 30.0
1=yes 0=no
(1000 m3)
Earthworks volumes
Calculation embankment width area Unit cost Total
(m) (m) (m2) (TT/m3) (M TT/m3)
top width 1.50 1.50 4.50 cut/fil l 49.7 30 1.5
height 3.00 compacting 49.7 0 0.0
outside slope 1: 1.50 4.50 6.75 cut/remove 235.6 30 7.1
inside slope 1: 1.00 3.00 4.50 topsoil 26.1 30 0.8
bottom width 9.00 15.75 topsoil transport 26.1 0 0.0
topsoil removal 0.20 m realised volume 560.4
depth below level 3.00 m required volume 556.9
LBP R3 additional 1 cost estimate M TT$ 9.3 9.3
Pond losses dry season 0 m unit cost 1m3 TT$ 30.0
1=yes 0=no
(1000 m3)
Earthworks volumes
151
The feasibility of adding plots to the LBPS needs to be investigated. Further optimisation by
adding plots to other LBPS can also be considered.
1.5.3 Pumps and cross weirs
For considerations on the pumps and cross weirs see 1.2: (Scenario 2: Using the Caparo
River from the RSSP to Felicity. Detailed design of cross weirs is not possible due to time
constraints and lack of information.
1.5.4 Irrigation management / scheduling
By reducing the maximum flow used to fill the on-farm ponds a significant saving in
investment can be realised (the tertiary pipes can be smaller). The meeting decided that for
Phase 1 separate pipes to the ponds and valve manifolds along the roads are to be
implemented. At a later stage it is possible to install telemetry. It is proposed to run Phase 1
as a pilot for at least three years and evaluate before extending to the full area.
152
2. SECONDARY SYSTEM
2.1 General
A major concern in the distribution system is the ease of operation and the energy use, of
which the latter is for only a minor part determined by the distribution system. Under all three
options presented here the energy use is the same.
2.2 Lay-out and operation
The secondary system is oriented along the Caparo River, where 7 (out of 9) LBPs are
located, with a connecting balancing pipeline, or the (future) RSSP pipeline. From the
(RSSP) pipe line the laterals branch off, all with the same capacity of 61 l/s (3 full flow shares
to fill a pond53 with 2 m of water in 12 hrs = 55.5/0.90 = 61 l/s per lateral). On any one lateral
there will never be more than three ponds being filled at the same time. Depending on the
design there will be 8-10 laterals taking off of the main pipe, but there will never be more than
10 on-farm ponds taking full flow: the capacity of the main system is 200 l/s:
10* 18.5 /(ep*es) = 185/(0.95 * 0.90) = 195 l/s ≈ 200 l/s
The sub laterals’ and pond supply pipes’ designs depend on the options in the secondary
system (see para 3.3).
Ease of operation is typified by the effort the farmers and the O&M staff have to exert to
operate the system. A (semi-)central operation is proposed for the system so that the
individual farmers cannot tamper with the supply and the system will be used in a
responsible way: a government appointed or, preferably, a WUA appointed operator will
open and close the valves in a predetermined manner. There is flexibility in the system in
terms of flows per pond (100%, 50% 25% of full supply flow), which allows for varying fillings
(0.5, 1.0 and 2.0, m per filling) and over varying delivery periods (T = 6 hrs, 12 hrs, 24 hrs
and 48 hrs, although preliminarily, in phase I, one delivery period is chosen: 6-8hrs per day,
5 days a week; once the entire scheme is implemented this can be easily fitted in into the
then prevailing water scheduling arrangements).
For the distribution system the actual operation concentrates on the opening and closing of
the valves, i.e. setting and locking the valves, safeguarding the valves against tampering,
and ensuring the accessibility of the infrastructure.
The accessibility turned out to be the most pressing issue. All on-farm ponds are located
near the drain: to ensure short spilling lines to the drain in case of overtopping and spilling or
worse; and presumably also to allow for easy supply from the same drain.
The best location for sub-laterals, branching off from the laterals, would be along the
(existing) farm roads, where an operator could easily access all the valves to the ponds. It
would also mean that the supply pipes to the pond would have to be almost 100 m from the
sub-lateral, adding to the vulnerability and cost of the system.
A better option would be to have the sub-laterals along the drains, one on each side;
however there are no good maintenance/access roads along the drains (at most only on one
side) so for the operator it will be cumbersome to operate all the gate valves. Even if a
maintenance road is available that leaves the other side of the drain where an equal number
of gate valves is located, out of reach. A possibility here is to have the connecting pipes
53
Standard size pond; if smaller ponds are adopted more ponds need to be filled at the same time along the same lateral branch.
153
cross the drain: this increases the vulnerability of the system (pipes would be in the open)
and complicates mechanised maintenance of the drains. Another option is to connect all the
ponds directly to the lateral, and provide each pond with its own supply, adding significantly
to the length of (small diameter) pipes, but making operation very easy: on the main road,
straight on the laterals are the manifolds with all the pond pipes grouped together.
Disadvantage is (like in the case of sub laterals along the roads access, or half the ponds in
case one maintenance track along the drain) that the operator never needs to get near to the
ponds anymore, which deprives the organisation of an important monitoring tool in water use,
efficiency and status of the pond. Regular checks on all ponds need to be scheduled by the
operator, and reporting on levels should be done at least weekly.
The pipes that fill the pump are fitted with a valve with three stops. The pipe downstream of
the valve will extend from the (sub-)lateral and near the pond rise from the soil to a height of
max. water level + 0.5 m.
2.3 Options of secondary system – Works description and BoQ
For three options the design has been detailed and the BoQ has been determined. All pipes
are buried: main pipes, laterals, sub-laterals and pond supply pipes in trenches: Width of the
trench is 3 * Ø (min. 50 cm), Depth is Ø + 1.0 m.
For option 1, the preliminarily selected option, a more detailed BoQ a has been prepared.
Three laterals, Ø300 (12”) B3-1, B3-2 and B3-3, make up the backbone of the Block 3,
selected for the Phase I development. The laterals are placed under the road drains, or on
the field of the farmers where the drain is of a larger order.
Any valves for sub-laterals (options 2 and 3) or manifolds (option 1) are placed on the
farmers land, unless unallocated land is available. All such infrastructure will be protected by
lockable protection boxes, iron wiring, or concrete rings, soundly fixed with concrete steel
and anchors in the soil.
Option 1
Each tank is supplied through its own pipeline. On the laterals are 4 and 6 pipe manifolds
that supply the pond supply lines. The manifolds connect through a Tee to the lateral.
Option 2
Three laterals: Lat 3-1, Lat B3-2 and Lat 3-3. The ponds are connected to sub-laterals on
each side to the drain by a supply pipe of approximately 15 m.
Option 3
As option 2, but with connected laterals to increase robustness; this may reduce pressure
differences in a block, if between blocks (final delineation not yet decided upon) also
connected laterals are implemented this may de stabilise pressure variations: to be further
investigated.
The design assumes pond filling flows of 18.5 l/s; if, as discussed, smaller tanks are placed
in the field smaller flows may be used as well. This may allow smaller pond supply pipes, and
in some cases also smaller laterals. However, many more tanks will need to be filled at any
one time, even though more water is supplied throught the main pipe, the laterals have a
combined capacity more than enough to handle such flows.
154
Figure 3: Map phase I, option1
155
Lateral and MF-code
No of supply lines
Distribution of distances and diameters over supply pipes, per manifold Length supply lines (Opt 1) Sub-laterals (Opt 2)
up 100 m: Ø 100 up 250 m: Ø 125 over 250 m: Ø150 Ø 100 (4") Ø 125 (5") Ø150 (6") Ø 100 (4") Ø 125 (5") Ø150 (6")
Lat 3-1 (m) (m) (m) (m) (m) (m) (m) (m) (m) (m) (m) (m) (m) (m)
MF3-1-1 4 20 120 220 320
20 340 320
320
MF3-1-2 6 40 130 200 270 340 410
40 330 1020
410
MF3-1-3 7 20 90 160 230 300 370 440
110 390 1110
440
MF3-1-4 7 20 90 160 230 300 370 440
110 390 740
370
MF3-1-5 4 20 110 200 290
20 310 290
290
MF3-1-6 4 20 110 200 290
20 310 290
290
MF3-1-7 6 20 90 160 230 300 370
110 390 670
370
MF3-1-8 7 20 90 160 230 300 370 440
110 390 1110
440
MF3-1-9 7 20 90 160 230 300 370 440
110 390 1110
440
MF3-1-10 8 20 80 140 130 190 250 320 360 100 710 680
360
Lat 3-2
Ø 100 (4") Ø 125 (5") Ø150 (6") Ø 100 (4") Ø 125 (5") Ø150 (6")
MF3-2-154
7 20 20 90 120 140 210 270
130 470 270
210
MF3-2-2 5 20 50 110 170 220
70 500
220
MF3-2-3 5 20 50 110 170 220
70 500
220
MF3-2-4 5 20 50 110 170 220
70 500 0 220
MF3-2-5 6 30 75 130 105 280 360
105 235 640
360
MF3-2-6 5 30 75 130 105 280
105 235 280
280
MF3-2-7 6 20 2 80 85 120 150
22 285
80
Lat 3-3
Ø 100 (4") Ø 125 (5") Ø150 (6") Ø 100 (4") Ø 125 (5") Ø150 (6")
MF3-3-1 5 20 50 110 170 220
70 500 0 220
MF3-3-2 6 20 50 110 170 220 270
70 500 270
270
MF3-3-3 6 20 50 110 170 220 270
70 500 270
270
MF3-3-4 8 20 20 80 140 200 260 320 380 120 340 960
380
MF3-3-5 8 60 120 180 240 300 360 420 480 60 540 1560
480
13255
Totals (m) 962 5,105 4,320 - 960 2,250
54
extra-long individual supply line under option 2 (and 3) required for plot 77 55
assuming compensation for adjusted ponds
156
Table 9: Bill of quantities and preliminary cost estimate Phase I – Felicity irrigation project
L P Cost L P Cost L P Cost
Main Supply (Balancing) Pipe (per 19 ft) TT$ (per 19 ft) TT$ (per 19 ft) TT$
Q=185 l/s ; Ø = (400); 1150 2400 476,585 1150 2400 476,585 1150 2400 476,585
Laterals
B3-1, Q=61.05 l /s ; Ø=125 850 550 80,726 850 550 80,726 850 550 80,726
B3-2, Q=61.05 l /s ; Ø=225 (300) 1500 2000 518,027 1500 2000 518,027 1500 2000 518,027
B3-3, Q=61.05 l /s ; Ø=150 650 700 78,567 650 700 78,567 650 700 78,567
ConLatera l B3-1-2, Q=61.05 l /s ; Ø=150 20 550 1,899
ConLatera l B3-2-3, Q=61.05 l /s ; Ø=150 700 550 66,480
Pond supply lines/Sublaterals
Q=18.5 l /s ; L<100 m; Ø=100 1712 400 118,248 1980 400 136,759 1980 400 136,759
Q=18.5 l /s ; 100 m <L <250 100 m; Ø=125 9055 550 859,969 960 550 91,173 960 550 91,173
Q=18.5 l /s ; L > 250 100 m; Ø=150 11960 700 1,445,642 5980 700 722,821 5980 700 722,821
Total pipes 26,877 3,577,765 13,070 2,104,659 13,790 2,173,038
Installation: labour, eng. (50% of purchase price) 1,788,882 1,052,329 1,086,519
Earth works TT$/m3 TT$/m3 TT$/m3
Trenching Main Pipe B = 0.6, D = 1.9 1,150 45.6 52,440 1,150 45.6 52,440 1,150 45.6 52,440
Trenching Latera ls B = 0.6, D = 1.8 3,000 32.4 97,200 3,000 32.4 97,200 3,720 32.4 120,528
Trenching Sub-Latera ls B= .5, D = 1.7 120 25.5 3,060 6,940 25.5 176,970 6,940 25.5 176,970
Trenching Pond Pipes B=0.6, D=1.8 22,727 5.4 122,726 1,980 5.4 10,692 1,980 5.4 10,692
Appendages
Manifolds 300 Y 14 3048 42,665
Elbow 90 28 121 3,381
Pipe 14 4945 69,230
T 150 16 53 846
T100 23 48 1,111
Elbow 90 117 199 23,277
7 300 Total MF 20073 140,510 NA NA
150 Y 30 2032 60,950
Elbow 45 60 81 4,830
Pipe 30 3297 98,900
T 150 45 35 1,587
T100 48 32 1,546
Elbow 90 279 133 37,005
15 150 Total MF 13382 204,817
Valves Supl . Pipes 4" 43 960 41,280 132 960 126,720 132 960 126,720
5" 54 1075 58,050
6" 35 1285 44,975
SubLats 5" 1 1075 1,075 1 1075 1,075 1 1075 1,075
6" 1 1285 1,285 1 1285 1,285 2 1285 2,570
8" 1 1820 1,820 1 1820 1,820 2 1820 3,640
Tees 132 800 105,600 132 800 105,600
Protection boxes MFs 22 2000 44,000
Protecion boxes Valves 132 500 66,000 132 500 66,000
Bends (incl conc. Foudations) 120 300 36,000 264 1000 264,000 264 1000 264,000
Tees (s teel / i ron) 28 1000 28,000 264 1000 264,000 23 1000 23,000
Tees (PVC) 132 250 33,000 132 250 33,000
Pressure regulators (each S-latera l ) 22 2000 44,000 22 2000 44,000 22 2000 44,000
Concrete works
Manholes for Manifolds (Tees) 242 5000 1,210,000 14 2000 28,000 14 2000 28,000
Manholes for Pond va lves 0 2000 - 132 2000 264,000 132 2000 264,000
Total Appendages 2,131,239 1,536,802 1,322,235
Miscellaneous
Buffer tanks against water hammer
Additional Pressure regulators (latera ls ) 10% 749,788.54 469,379.02 458,179.26
Water meters
Grand total Distribution system 8,247,674 5,163,169 5,039,972
Option 1: separate pond supply pipelinesOption 2: sub laterals Option 3: sublaterals, connected lateralsDescription Item
157
3. WATER QUALITY AND SALINITY
In general salinity issues are limited to (semi-)arid regions; however, in sub-humid regions
salinity can also occur. These are generally related to local salinity sources such as sea
water intrusion, a geological origin, pollution, etc.
In Trinidad there seems to be salinity problem in a wide area in West-Central-Trinidad, and
the origin of the salinity has not been established. A specific case seems to have been
identified in the Felicity irrigation scheme, where water quality samples have been taken from
two rivers (Caparo River and Chandernagore River) and three ponds. The water quality was
fair (see Chapter 11.3), however, one pond showed very different results.
It is unclear how a 4 m deep pond could have turned saline. Possible causes of this low
quality water were not apparent and a number of mechanisms was evaluated.
Concentrating through evaporation
Over the dry season the evaporation is higher than precipitation and salinity levels in a pond
of water may increase. Over the wet season the opposite process takes place and salinity
levels will drop, even some spilling may occur and salts may be flushed out. A (long term)
annual increase of salinity will require an external source of salts.
There are several possible external sources of salt. Salinity through salt intrusion from the
sea, shallow geological deposits and salinity build-up through agricultural practices are all
possible sources.
Sea water intrusion seems unlikely in the case of the Felicity irrigation scheme as the area
has an elevation of 8 to 12 m above MSL, and the ground water is approximately 4 to 8 m
above MSL, with overall a steady drainage flow.
Geological salt at a shallow depth is possible. In a shallow layer it would have been picked
up by rivers a long time ago, cutting through the layer in the erosion process, but at the time
there were no agriculturalists (or engineers) to worry about such a process or even detect it:
water (slightly saline) washed into the sea.
Agricultural practices could also be a source though the process is not very obvious. Under normal
conditions there is a solid surplus of precipitation in Trinidad over drainage. A natural leaching
process is expected. However in C-Trinidad the surplus is not very high. Furthermore in the clayey
soils of C-Trinidad the leaching fraction of precipitation may be relatively small: there is quite some
overland flow under natural conditions and (natural) leaching may not have been as much as thought
likely. As rainfall does not add salt to the soil water mix, a slow, long term leaching process may have
taken place; in the heavy clays of C. Trinidad, however, an unnoticeable process. The long term
cultivation of sugarcane (200 years) may have changed that. More infiltration may have occurred
because of more roughness on the field, and a stronger leaching process might have occurred.
However, sugar cane transpires a lot more than the previous natural vegetation (adapted to the
relatively low infiltration/leaching faction), and drainage-cum-leaching may have slowed down or
even come to a standstill. The application of fertiliser, organic or chemical, may have added to the
salt load in the soil. When drainage-cum-leaching was reduced to a trickle, salinity may have
accumulated in the lower layers of the root zone or just below. An analogous process was described
in detail in Saudi Arabia (a real arid climate) under irrigated date palms over a 30 year period
(Reference: Evaluation and Development Study of the Irrigation Water Distribution System in Al-
Hassa Area”, 2003).
158
This is still a hypothesis and, together with the shallow geologic saline deposits, deserves
more study. The real issue is to ascertain whether indeed salinity is a widespread problem as
being claimed by certain people in the field, or indeed that the saline pond is a freak incident
with merely local implications.
Salinity in the future
For the long term however agricultural practices may certainly play a role in salinity
development. The precipitation surplus will further reduce, Pe will reduce, if not relatively it
will reduce in absolute numbers, and (irrigation) water quality may deteriorate.
Under normal circumstances there is a fraction of the water that infiltrates into the soil
(precipitation and irrigation water). Irrigation water carries salt, even if only very small
amounts, rainfall is free of salts.
where,
R* = balance of leaching and recharge from ground water
Ii = volume of irrigation water
Pe = effective precipitation (infiltrating precipitation)
An equilibrium, important to stave off salinity damage to crop and soil (SAR), is reached if the
salt balance is zero. This can be achieved when the leaching requirement (LR) is fulfilled.
The LR is described by the following relation:
LREC
EC EC
w
e w
5
LR = leaching requirement
ECw = electric conductivity irrigation water
ECg = (allowable) ECe at an accepted yield loss level
Reference is made to FAO Publications 29 (Water quality for agriculture) and 61 Agricultural
drainage and water management in (semi-) arid areas).
159
4. METHOD OF PIPE DESIGN
4.1 Operation and design
In the secondary system an important criterion is to limit pressure difference in a pipeline: if
the pressure difference is too high large deviations between the first and last lateral, sub-
lateral of supply line may occur. In the laterals, long or short, the maximum head difference
between first and last branching off sub-lateral, is put at 15 m water pressure (150,000 Pa).
This explains why some laterals have a smaller diameter than other while the discharge is
equal.
In sub-laterals and supply lines the maximum head differential is limited to 5 m water
pressure. In spite of the design it is accepted that larger differences will occur and these will
be compensated at the lateral where the sub-lateral or supply line branches off. Pressure
regulators will be installed at those points. For pressure regulators to work excess pressure
is required and the operating pressure of the system at the head of the lateral is as follows
(Table 1.10).
Table 10: Make up of pressure in laterals
5 m Pressure at nozzle supply pipe at tank
5 m Head loss over supply line or sub lateral
15 m Head loss over lateral
20 m Additional head available for pressure balancing in laterals
45 – 50 m Total head available at head of lateral
15 m Head loss over main pipe / balancing pipe in secondary system
60 – 65 m Total head required at head of main pipe – balancing pipe
The pressure losses have been (preliminarily) determined through applying the general flow
formulae, but for ease of quick reference the head losses as shown in Figure 4 have been
used. Losses in appendages have not been included yet but are of a lower oreder than these
pipe losses; yet these have to be determined. For the balancing pipe, the pipe that allows
different pumps (and ponds) to convey water to different parts of the system, while npt
effecting the pressure distribution over the system too much, the flows and pressure losses
have been compiled in Table 10. In the ideal situation, at each lateral flow is being diverted
from the pipe into a lateral. The worst case is being presented here: full flow from the supply
of the RSSP enters he system, and flow is being diverted at each lateral. The impact of the
use of the smaller pipes (1’ or Ø300 vs. 1’4” or Ø400) is obvious. In the smaller pipe a much
larger head loss will occur (12.5 m) than in the larger pipe (27.5 m). This means that more
energy will be wasted and that the pump will require a larger capacity to allow such a flow.
Careful optimisation will allow lower investment costs and lower energy costs. This requires
further investigation.
160
Table 11: Head losses in balancing (transport) pipe.
RD (m)
Q Ø400 (1’4”) Ø300 (1’)
(l/s) (m3/hr) (gipm) Δh/100m Δh (m) Δh/100m Δh (m)
0
600 200 720 2632 0.85 5.1 1.95 11.7
1200 180 648 2368 0.60 3.6 1.30 7.8
1800 140 504 1842 0.30 1.8 0.70 4.2
2800 100 360 1316 0.15 1.5 0.35 3.5
3000 60 216 789 0.08 0.2 0.03 0.1
12.2 27.3
161
Figure 4: Head losses (m water pressure) per 100 m pipe
162
ANNEX 12: ASSIGNMENTS CONSULTANTS, MEETINGS AND FIELDWORK, PERSONS
MET
Assignments Consultants
Name
Position Period 2013
Frank de Zanger
Team Leader, Water Resources Management Expert
June 9 – September 13
Bob Pengel
Water Resources Development Expert
June 23 – July 13 July 29 – September 13
Frank van Berkom
Hydrologist August 21 – September 10
Luis Celis
Hydrologist June 16 – June 30
Meetings and fieldwork
Date Meetings, Fieldtrips Location & Details
11-6-2013 EU Delegation Level 2, Sagicor Financial Centre, 16 Queen’s Park West, Port of Spain, tel. 622 6628 / 622 0591 / 622 0615
14-6-2013 Environmental Management Authority (EMA)
8 Elizabeth Street, St. Clair, Port of Spain, tel. 628 8042
17-6-2013 County Caroni Extension Office, Chaguanas, Ministry of Food Production (MFP)
LP 525 Old Southern Main Road, Chase Village, Chaguanas, tel. 672-0878, 627 2865; [email protected]
17-6-2013 Fieldtrip
Felicity Project Area
18-6-2013 Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
18-6-2013 Caroni (1975) Limited Brechin Castle, Couva, tel. 636 2346/9912, 679 2255
20-6-2013 Caribbean Agricultural Research and Development Institute (CARDI)
Frederick Hardy Building, University of the West Indies, St. Augustine Campus, St. Augustine
21-6-2013 Drainage Division, Ministry of the Environment and Water Resources
NIDCO Building, 5th floor, Melbourne Street, Port
of Spain. Tel. 623 3158/379 6996
26-6-2013 Weekly progress meeting. Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
26-6-2013 Fieldtrip
Felicity Project Area
3-7-2013 Weekly progress meeting. Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
9-7-2013 Meeting with farmers 5-6 kms east of project area (Depot Road Irrigation Scheme): County Agricultural Consultative Committee. Organised by County Caroni Extension Office, Chaguanas, Ministry of Food Production (MFP)
LP 525 Old Southern Main Road, Chase Village, Chaguanas, tel. 672-0878, 627 2865; [email protected]
163
10-7-2013 Weekly progress meeting. Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
10-7-2013 Fieldtrip, guided by Drainage Division of Ministry of Environment and Water Resources
Irrigation / drainage system North of Felicity
Project Area
11-7-2013 Meeting at Project Office of Royal Haskoning/DHV, conc. Caparo River Basin Study
36A Carlton Avenue, St. James, Port of Spain, tel. 868 628 5767
17-7-2013 Weekly progress meeting. Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
24-7-2013 Weekly progress meeting. Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
31-7-2013 Weekly progress meeting. Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
3-8-2013
Field trip to sand mining pits/sinks East of the Felicity Project Area with Mr. Johan Mathijssen, Team Leader of the Caparo Water Basin Study, HaskoningDHV-Deltares.
Field trip to mining pits/sinks East of the Felicity Project Area
7-8-2013 Weekly progress meeting. Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
7-8-2013 Meeting at the Trinidad and Tobago Meteorological Service Division
Piarco
12-8-2013 Taking water samples in the project area with technicians of CARIRI laboratory and officials from MFP
Felicity Project Area
12-8-2012 Rapid appraisal; consultation with farmers working in the Felicity Project Area
Felicity Project Area
14-8-2013 Weekly progress meeting. Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
20-8-2013 Meeting at the Town and Country Planning Division, Ministry of Planning and Sustainable Development
Twin Towers, Port of Spain
23-8-2013 Introduction meeting at Agricultural Extension Office, Introducing Mr. Frank van Berkom
Mausica Road, Centeno
23-8-2013 Sugar Cane Feed Lots Pokhar Road, Longdenvill, Chaguanas mob.1-868-365-1103,email: [email protected] [email protected]
23-8-2013 Mr. Roop’s Demonstration Farm Usire Road, Freeport ph. (868) 367-8655, fax: (868) 671-9179 email: [email protected]
27-8-2013 Workshop Caparo River Basin Study (Drainage Division, NIDCO)
Tower D, International Water Front Complex, Wrighton Road, Port of Spain
28-8-2013 Presentation of options for irrigation, progress meeting.
Mausica Road, Centeno
164
Extension Training and Information Service Division, Ministry of Food Production (MFP)
29-8-2013 Meeting with engineers on design of irrigation scheme
Mausica Road, Centeno
3-9-2013 Meeting with engineers on design of irrigation scheme
Mausica Road, Centeno
6-9-2013 Presentation of the draft Final Report and discussion of the results, comments. Extension Training and Information Service Division, Ministry of Food Production (MFP)
Mausica Road, Centeno
6-9-2013 Meeting with engineers on design of irrigation scheme
Mausica Road, Centeno
9-9-2013 Last meeting on design of irrigation scheme
Mausica Road, Centeno
PERSONS MET
EU Delegation Level 2, Sagicor Financial Centre, 16 Queen’s Park West, Port of Spain, tel. 622 6628 / 622 0591 / 622 0615
Kathrin Renner [email protected] EU Delegation
International Aid Officer / Attaché
Solomon Ioannou
[email protected] EU Delegation
Programme Officer
Environmental Management Authority (EMA) 8 Elizabeth Street, St. Clair, Port of Spain. Tel. 628 8042
Christiaan Harragin 628 8042 /4308 [email protected],tt
EMA Senior Technical Specialist
Xio Mara Chin
EMA
Water Resources Agency, WASA 179-181 Eastern Main Road, Barataria
Anthony Chadee 678 1282 [email protected]
Water Resources Agency, WASA
Deputy General Manager
Sara-Jade Govia 466 7475 [email protected]
Water Resources Agency, WASA
Environmental Specialist
Philmore Williams 686 1899 [email protected]
Water Resources Agency, WASA
Senior Hydrologist
David Samm Water Resources Agency, WASA
Senior Hydrologist
County Caroni Extension Office, Ministry of Food Production (MFP) LP 525 Old Southern Main Road, Chase Village, Chaguanas. Tel. 672-0878, 627 2865; [email protected]
Mala Powdhar [email protected] Engineering Division MFP, Irrigation & Drainage
Agricultural Engineer II
Joel Ramadoo 642 0363, 646 0267 [email protected]
Engineering Division MFP
Engineer I
Garth Roach County Caroni Agriculture Assistant II
165
Office
Ivan Dadd 487 9824 County Caroni Office
Agriculture Assistant I
Ministry of Food Production (MFP) Extension Training & Information Service Division, Mausica Road, Centeno; Port of Spain
Ann Marie Dardaine
717 4151 [email protected]
Engineering Division MFP
Director
Frankie Balkissoon 472 1707 642 0267 / 0363 [email protected]
Engineering Division MFP, Irrigation & Drainage
Deputy Director
Yvonne Davidson McKenzie
622 1221 ext. 2140/ 622 5953 [email protected]
Agricultural Planning Division (APD) MFP
Planning Officer III
Beena Persad 798 3224 [email protected]
Agricultural Planning Division (APD) MFP
Planning Officer I
Mala Powdhar [email protected] Engineering Division MFP, Irrigation & Drainage
Agricultural Engineer II
Candace Maharaj 714 3272 [email protected]
Fisheries Division MFP Junior Civil Engineer
Candice Gray-Bernard
721 5544 [email protected]
Fisheries Division MFP Senior Civil Engineer
Cavelle Motilal 772 8607 / 642 0267 [email protected]
Engineering Division MFP
Engineer
Caroni (1975) Limited Brechin Castle, Couva. Tel. 636 2346/9912, 679 2255
Deosarran Jagroo 681 4845 Caroni (1975) Ltd. Chief Executive Officer
Johnny Ribiero 789 5097 Caroni (1975) Ltd. Felicity farmer contacts
Michelle Gittens 705 9313 Caroni (1975) Ltd. Project Manager
Russel Boland 794 4358 Caroni (1975) Ltd. Lands Leader / Mgr.
Royal Haskoning / DHV - Deltares 36A Carlton Avenue, St. James, Port of Spain, tel. 868 628 5767 Johan Mathijssen
868 468 2615 [email protected]
Team Leader / Project Manager
Caribbean Agricultural Research and Development Institute, CARDI Frederick Hardy Building, University of the West Indies, St. Augustine Campus, St. Augustine
Norman Gibson 645 1205-7, [email protected] www.cardi.org
CARDI Scientific Officer
Caribbean Industrial Research Institute, CARIRI University of the West Indies, St. Augustine Campus, St. Augustine
Gaitri Jeethan mob. 4915558 [email protected]
CARIRI Chemist Analytical Chemistry
166
Caribbean Agribusiness Association Department of Agricultural Economics, Rm.l09, University of the West Indies, St. Augustine Campus, St. Augustine
Ramgopaul Roop
mob. 1-868-365-1103, Email: [email protected] [email protected]
Department of Agricultural Economics
Regional Administrator
Dinal Enterprises, Agricultural Consultants & Contractors
Main Road Longdenville, Chaguanas, Trinidad
Roopnarine Siewnarine
Ph. (868) 367-8655 Fax: (868) 671-9179 email: [email protected]
Farmer, consultant
Trinidad and Tobago Meteorological Service Division Piarco, airport area
Kenneth Kerr mob. 4624790 [email protected]
Climatologist
Town and Country Planning Division, Ministry of Planning and Sustainable Development Independence Square, Twin Towers, Port of Spain
Clyde Watche
Town and Country Planning Division
Director
Kerry Pariag
Town and Country Planning Division
Planning Engineer
Drainage Division, Ministry of the Environment and Water Resources NIDCO Building, 5
th floor, Melbourne Street, Port of Spain. Tel. 623 3158/379 6996
Shamshad Mohammed
Drainage Division, Ministry of the Environment and Water Resources
Director
Ramdaht Baboolal 468 0481 [email protected]
Drainage Division, Ministry of the Environment and Water Resources
David Persaud Drainage Division, Environmental Policy and Planning, Ministry of the Environment and Water Resources
Manager
Drainage Division, Ministry of the Environment and Water Resources Chaguanas
Sahedee Ramoutar
Drainage Division, Ministry of the Environment and Water Resources
Work Forman I
167
ANNEX 13: TERMS OF REFERENCE
Annex 13 Terms of Reference
168
ANNEX 14: WORK PLAN AND TIME FRAME
Consultants: F: Frank de Zanger B: Bob Pengel L: Luis Celis V: Frank van Berkom
Project Activities, 2013 June July August September
wk1 wk2 wk3 wk4 wk5 wk6 wk7 wk8 wk9 wk10 wk11 wk2 wk13 wk14
On mission F F F F F F F F F F F F F F
On mission B B B B B B B B B B
On mission L L V V V
Reporting F F F F F F F F F F F F F F
Liaison with Delegation of the EU F F F F F F F F F F F F F F
1
Meetings with the EU Delegation and
representatives of GoRTT, WASA, MFLMA and
other identified agencies to obtain feedback
F
FL
FL
2
Data collection on hydrology, meteorology,
irrigation, aerial photography, socio-economy,
legislation, policy, environment
F LF
BFL BF BF
F
F
BF BF
3
Submission of Inception Report with Work
Plan
X
4 Comments on Inception Report X
5
Revision by Consultants
X
FBL
6 Approval of Inception Report X
7
Overview/description of the National Sugar
Adaptation Strategy (NAS) and its institutional
and legislative framework
FL
FB
8
Identification of precise project area. Field visits FL
FBL
9
Identification and description of stakeholders in
the project area. Field visits
FBL
10
Meetings with stakeholders in the project area and
obtaining their feedback. Field visits
FBL BF
11
Study on set up of water users associations. Field
visits
BF
169
12
Assessment of the existing situation for irrigation
and drainage, including water and wastewater
systems, in the project area. Field visits
FL
BFL
13
Review of existing institutional arrangements for
water resources development and management.
Field visits
BF
14
Needs assessment in the project area. Field visits.
BF
15 Irrigation Sector Study
15a Assessment of drainage and flooding B
15b
Estimation of current, future and potential
agricultural water resource needs
B
15c
Hydrological,watershed study to determine water
availability
BF
F
F
15d
Aerial photographs / satellite image interpretation
15e
Identification of trends and projects proposed on
the short, medium and long-term, taking into
account external factors, including influence of
other sectoral policies
BF
F
F
15f
Potential environmental impacts of irrigation
system (agricultural runoff) on surrounding rivers,
other drainage features, and downstream users
(domestic, industrial, ecosystem water demands)
F
F
F
15g
Formulation of mitigation measures to deal with
changing catchment characteristics
F
F
15h
Identification of various options for the
development of sustainable water management
(irrigation/drainage) in the Felicity area. Field
visits
BF
BF
15i
Defining a preferred option for irrigation and
drainage of agricultural lands in the Felicity area
(1300 acres), serving as a model for the rest of the
country. Field visits
BF
16 Feasibility Study and Preliminary Design
170
16a Water supply (abstraction) and delivery BF BF
16b Water storage and head works B B VB VB VB
16c Distribution system to farmers B VB VB VB
16d Drainage works B VB VB VB
16e
Waste water treatment facilities (with closed loop
system) and reuse options, if required
B VB VB VB
16f
Economic analysis providing guidance to the
economic feasibility of the project and potential
for funding by regional/international lending
agencies
BF BF
16g Proposal for cost for water BF
16h Addressing environmental issues F
16i
Farmers involvement in the operation and
management of the project
B
17 Preparation of contract and tender documents V V V
18
Formulation of conclusions and recommendations
FBV FB F
19 Organising a stakeholder workshop FB
20 Revision of draft Final Report FB
21 Submission of Draft Final Report X
22
Comments on Draft Final Report by the EU
Delegation, including comments by
representatives of the GoRTT and other
stakeholders
X
23
Revision by the Consultants
X
FB
X
FB
24
Submission of Final Report
X
25 Approval of Final Report
