Ground Water Artificial Recharge in Spate Areas · 2017-08-07 · Ground Water Artificial Recharge...
Transcript of Ground Water Artificial Recharge in Spate Areas · 2017-08-07 · Ground Water Artificial Recharge...
Ground Water Artificial Recharge in Spate Areas
(case study Wadi Ahwar in Yemen,)
Dr. Abdulla Noaman
Dr. Sharafaddin A. Saleh
INTRODUCTION
This report responds to the TOR and the data collection and analyses the results of which
were used in creating certain thematic groundwater maps reflecting the groundwater
conditions in the Ahwar Delta. The report also presents data collection activities and
details of the required monitoring system.
Figure 1. Location Image of Delta Ahwar in Yemen
The study area has been witnessing groundwater irrigation development besides spate
irrigation with flood water. Agricultural development in Ahwar has started within the
framework of the GOY sustainable agricultural development perspective Year of
Agriculture (1984) which situates irrigation based agriculture at the heart of agricultural
development strategy in Yemen. After the year 1990, Agricultural development in Delta
Ahwar was has been escalated since the construction in 1990 of the Fuad and Hanad weirs
as well as through the increase of agricultural productivity through the expansion of
groundwater irrigated agriculture. To that effect extensive shallow tube wells (STWs) were
drilled and equipped in Delta Ahwar area.
Study Area
Delta Ahwar is located about 200km east of Aden. Ahwar, Al Hanad and Al Mabrak along
the coast of the Arabian Sea are major villages in the delta; the study area is also
considered as the flood plain delta of wadi Ahwar
Figure 2. Image showing Wadi Ahwar main drainage system and delta on the Arabian Sea
Ahwar Delta and main villages showing high resolution Images dates
4.0 CONJUNCTIVE USE OF SURFACE AND GROUNDWATER
In the Ahwar Delta, rain, and consequently peak runoff, which contributes to a significant
part of the total discharge of the wadis, occur during a particular season of the year. This
however, usually responds to smallest water demand. The water development problem
therefore is how to transfer water from the high supply season to the high demand season.
The most obvious and the most common solution would be storing surface water behind
dams. However, despite the fact that underground storage of water may be a valuable
alternative to surface storage systems, it is not always systematically considered when
planning water resources development. Surface reservoirs have many drawbacks, such as
loss of water by evaporation, sedimentation, the negative healthy impact on the human
environment and the high cost of water conveyance associated with surface water storage.
Conjunctive use of surface and groundwater consists of harmoniously combining the use of
both sources of water in order to minimize the undesirable physical, environmental and
economical effects of each solution and to optimize the water demand/supply balance.
Usually conjunctive use of surface and groundwater is considered within a wadi and delta
basin management program, in the same basin.
Assuming that the mixed solution is part of the national policy, several issues need to be
carefully studied before selecting the different options and elaborating a program of
conjunctive use of surface and groundwater:
• Underground storage availability to be determined,
• Production capacity of the aquifer(s) in term of potential discharge,
• Natural recharge of the aquifer(s)
• induced natural recharge of the aquifer(s)
• Potential for artificial recharge of the aquifer(s)
• Comparative economic and environmental benefits derived from the various possible
options.
5.0 UNDERGROUND STORAGE AVAILABILITY AND PRODUCTION
CAPACITY OF THE AQUIFER
In order to use the underground reservoir to store a significant volume of water, and use it
at a later stage, it is necessary to ascertain the potential storage capacity of the groundwater
reservoir as well as its suitability for being recharged by surface water and the water
recovery efficiency The groundwater reservoir should present sufficient free space between
the ground surface and the water table to accommodate and retain the water to be
recharged, for the period during which water is not needed. This condition requires
accurate hydro geological investigations including geological mapping, geophysics and
reconnaissance drilling, in order to determine the configuration and the storage capacity of
the underground reservoir.
The suitability of an aquifer for recharging may be estimated from the following
parameters:
• Surface material has to be highly permeable so as to allow water to percolate easily;
• The unsaturated zone should present a high vertical permeability, and vertical flow of
water should not be restrained by less permeable clayey layers;
• Depth to water level should not be less than 5 to 15 m, generally; the depth to water
table is rather deep in most of the delta for the application of this technique
• Aquifer transmissivity should be high enough to allow water to move rapidly from the
mound created under the recharge basin but should not be too high (as in karstic
channels) so that water cannot be recovered.
An adequate transmissivity of the aquifer material is also a good indicator of the aquifer
capacity to produce high well discharge and therefore easily to return the water stored.
6.0 NATURAL AND INDUCED RECHARGE OF THE AQUIFER
Natural recharge of the aquifer occur from the surface runoff and the deep percolation of
flood flows, as well as infiltration from adjacent water bodies, whether natural or artificial
such as reservoirs, lakes, and to a modest extent from irrigation water return, especially in
the case of shallow aquifers. To that effect should the average annual amount of recharge
be of the same order of magnitude as the water demand, there would not be the need for
any additional human intervention through the process of artificial recharge through the
modification of the natural course of surface water or the diversion of any surplus water
from an adjacent source.
Induced natural recharge occurs when intensive exploitation of groundwater close to a
river results in an important depression of the groundwater level and in a water inflow
from the river. This phenomenon is well known in temperate climate where rivers flow all
year long; but it may also occur in semi-arid climates where a depression of the
piezometric level of an aquifer underlying a temporary wadi deposits creates the empty
space in the aquifer which facilitates its recharge during floods.
6.1 Artificial Recharge
Artificial recharge of aquifers can be achieved using three different methods, namely
surface spreading, watershed management (water harvesting) subsurface dams and
recharge wells.
Surface spreading
Artificial recharge by the spreading method consists of increasing the surface area of
infiltration by releasing water from the source to the surface of a basin, pond, pit or
channel. This is certainly the most efficient and most cost-effective method for aquifer
recharge. However, only free (unconfined) aquifers can be recharged by the spreading
method, which also requires large surface areas to accommodate the recharge scheme,
allowing water to evaporate if percolation in the ground is slow.
Surface spreading usually needs two structures: the diversion structure and the infiltration
scheme.
Diversion structures are the same as those used for spate irrigation. The traditional
methods, based on centuries of experience, are well adapted to the conditions of arid land
wadis. They consist of the construction of earthen bunds (ogmas) and deflectors across the
wadi to divert the flow into the fields. But large spates usually destroy the ogmas and
reduce irrigation of the fields. Furthermore, the very high sediment content of spate water
tends to fill the diversion canals, which have to be cleaned regularly. So, although the
ogmas are relatively inexpensive to rebuild, the overall cost of seasonal maintenance and
repair of the scheme is high.
Several techniques have been tested with the objective of achieving a better control and
regulation of spate and reducing sediment transport in the canals. Due to the hydrological
characteristics of wadis, it soon became evident that it is not economic to provide diversion
weirs which will control the probable maximum flood. Thus, the tendency nowadays is to
build diversion structures with a canal head regulator, sediment excluder and a spillway on
one flank and a fusible dyke across the wadi. Unfortunately, present design and feasibility
studies are often hampered by lack of adequate data on spate runoff. These techniques
were developed with the intention of improving the spate irrigation systems, but the results
can apply to the diversion structures needed for artificial recharge by surface spreading.
The infiltration scheme may consist of basins, channels or pits depending on the local
topography and on land use. The most common system consists of a number of basins
each one having an area ranging from 0.1 to 10 ha according to space availability. Each
basin must have its own water supply and drainage so that each basin can be flooded, dried
and cleaned according to its best schedule. Basins should never be in series, because in
such a system, they cannot be dried and cleaned individually. Often the first basins are
used as pre-sedimentation facilities.
In the vicinity of urban areas, pits may have been dug in ancient paths of wadis in order to
extract construction material (gravel, sand). The depth of these pits may range from 2 to 3
m up to 30 to 40 m. Pits may also be excavated for the specific purpose of artificial
recharge. Aquifer recharge simply consists of diverting water from the main channel to the
pit. Even with a deep pit, it may be advisable to have a smaller settling pit between the
main channel and the larger recharge pit. Both recharge and settling pits should be fenced
and have a suitable inlet so that the inflowing water does not erode the walls of the pits.
Other techniques may also be identified with the surface spreading method: spate
irrigation, check dams, underground dams and sand dams.
Spate irrigation is a well known traditional technique in the area consisting of watering
terraced fields which flank the wadi, by diverting flood flows into them. Although the
primary objective of spate irrigation is not aquifer recharge, this technique usually
contributes significantly to increasing the infiltration of water into the underlying
groundwater reservoirs. The storage of excess water into the aquifer and its subsequent
retrieval alleviates some of the risks inherent to runoff based irrigation in arid zones.
Check dams are small structures built across wadis with a view to slowing down the
velocity of water, allowing it to percolate into the alluvial aquifer. When the wadi usually
flows into a narrow channel surrounded by plains located a few meters above the bottom of
the channel, check dams may be built in the channel, raised 1 to 2 meters above the ground
level of the plain and extended laterally by two wings crossing most of the stream bed. The
flood is then forced to pass through artificial meanders over a long path and large area and
to slow the flood velocities to enable the surface water to percolate and thus facilitating the
infiltration of water. However due to high silt load in runoff/flood water, check dams will
be subject to silt deposit and requires frequent desilting works.
Underground dams apply in shallow depth alluvial deposits to prevent groundwater
(underflow of the wadi) from flowing away immediately after it is stored in the aquifer.
They consist of digging a 1 to 1.5 m wide trench across the valley, down to the bedrock
and/or clayey impervious layer and then filling the trench either with loose impervious
material (clay) or by building a wall made of local bricks. Underground dams may be
complemented by sand dams consisting of raising the dam above ground by 1 or 2 meters
so that the solid transport (usually sand and gravel) of the floods can accumulate behind
the surface dam and thus increase the storage capacity of the alluvium. This technique may
not be suitable for a recharge system to the Ahwar area due to the depth of water which is
more than 40 meters in most of Ahwar Delta, detailed Hydrogeological and geophysical
sounding surveys should be conducted to determining the possible suitability of an
underground dam.
6.2 Watershed management and water harvesting
Watershed management offers an effective method to intercept dispersed runoff. Many
techniques of water conservation have been developed along hill slopes with the intention
of preventing soil erosion and reducing surface runoff, then increasing the infiltration in
the ground, thus recharging the aquifers. Traditional terraced agriculture is certainly one of
the most common water harvesting methods in arid areas and particularly in Ahwar upper
catchments. Where the terraces are well maintained, they effectively control runoff and
improve aquifer recharge but, once allowed to fall into disuse, they progressively lead to
gully erosion, collapse of the retaining walls, destruction of the whole system and severe
modification of the hydrological regime. Therefore, whatever the economic virtues of such
terraces, it should be recognized that their abandonment on a large scale can upset the
hydrological conditions within a basin for a considerable period of time.
Because of the siltation problems in the surface reservoirs resulting from soil erosion in the
upper catchment, large program of soil and water conservation as well as forestation
should be taken in several places of the Ahwar Catchment. Although the primary objective
of the watershed management is to limit the soil erosion and therefore to reduce sediment
accumulation in the surface reservoirs downstream, the effect of these practices may
become significant on the aquifer recharge when large areas are included in the programs.
Ahwar groundwater monitoring data both water level and water quality, should be stored
within a Groundwater Database system. The system should be based on web technology
and is available through.
Allocation and use data is obtained through the Database which is an electronic database
for water license details. Both databases are managed locally at district level, with respect
to the collection and entering of water monitoring, allocation and use data.
7.0 GROUNDWATER MANAGEMENT:
Management of the groundwater resource of the Ahwar Delta should aim at maintaining a
long term sustainable resource. Coastal aquifers prone to salt water intrusion, such as those
of the Ahwar Delta, remain capable of yielding a sustainable source of freshwater if
protective and flexible management practices are implemented. Protective management
requirements for the Ahwar Delta should include:
Construction and maintenance of the proposed subsurface dams of artificial
recharge scheme, with respect to replenishment encouragement and the
development of recharge pits, to ensure the long term sustainability of irrigation
based farming operations in the Delta;
Development of a groundwater management model for the Ahwar basin to assist in
evaluating the long-term water management strategies, consideration of the long
term protection of the groundwater system from saltwater intrusion, with
maintenance and continuation of water level and water quality monitoring.
Saltwater intrusion of the groundwater resources of Ahwar Delta could be a serious
problem in the coming few years, particularly after an extended drought period, which may
result in extreme reductions in groundwater levels below sea level due to excessive use.
Excessive demand placed upon the groundwater resources within the Delta has resulted in
water level declines and degradation of water quality in some areas of the Delta. The water
overdraft situation will finally be recognized after a severe drought, the implementation of
an artificial groundwater recharge scheme. Management of the water resources within the
Delta will significantly protect the aquifer, since the implementation of present irrigation
scheme, with the proposed underground system could be considered as one of conjunctive
use of both surface and groundwater.
Developing hydrological Monitoring system
Water-levels in piezometers, soil temperature, and several climatic parameters should
monitor automatically in the Ahwar Delta.
A monitoring network concept consisting of a number of groundwater monitoring wells
and a surface water station was conceived and evaluated to assess its overall effectiveness
at achieving the specific monitoring objectives, and to (1) identify potential opportunities
to streamline monitoring activities while still maintaining an effective monitoring program,
and (2) identify data gaps that may require the addition of additional monitoring points.
It should be indicated here that there are a variety of ground-water resource problems that
involve the Delta groundwater and affect detecting or predicting changes in the ground-
water environment... Any design for a monitoring system must combine techniques that
integrate stochastic ground-water flow and salinity transport /intrusion with optimization
for controlling and managing groundwater – surface water
Groundwater Levels fluctuations
Groundwater levels drop to more than 80 meters below ground surface in some parts of the
study area. However, several cones of depression occur in various parts of the study area,
whereby no accurate well elevations are available. To that effect, the Consultant prepared,
a tentative water table elevations contour map based on elevation readings measured by
hand held GPS. The contour elevation forms a close circle around the pumping wells in
farms. Despite the fact that this SWLE contour map is not reliable due to the lack of
accurate topographical survey, yet, it was observed that pH variation is directly related to
the depth to water level and water level depletion cones. Figure 5 represents a pH contours
map reflecting the actual depleted cone in the area, where one can observe that the main
groundwater flow direction is from North to South, but the flow direction has been
disturbed to receive water from all sides around the depleted cones.
Depth to water in the study area ranges from 10 below the surface along the sea coast in
the south to a maximum estimated at more than 80 meters below ground surface for some
parts of the depleted aquifer, Figure 6. In the Northern part of the delta area depth to water
is greater than 60 meters and is limited to some depleted cones as shown in the map below.
Reliable information describing the configuration of the water table in the Delta is needed
to help resolve a variety of water-resource issues including evaluation of aquifer
susceptibility to contamination, effects from storm water, evaluation of injection systems
for groundwater recharge, well drilling, and monitoring. Such a map would also serve as a
baseline to identify changes in water levels resulting from natural or human-induced
causes.
:.
Figure 6. Delta Ahwar depth of water table contour map
Abstraction
Estimation of annual abstraction of ground water by pumping were calculated at 24Mm3/yr
by applying the following two methods:
Total well discharge:
Based on the results of the well inventory, the total discharge of the wells in the delta was
estimated at 3143 l/sec., while the estimated total volume of abstracted water was 24 Mm,3
assuming that the number of pumping hours is 12 hr/day and number of operating days is
180 days.
Irrigated areas and farms count:
The groundwater irrigated area is estimated at 1930 herewith a total irrigation requirements
of estimated at 23.16 Mm3 (assuming the irrigation water requirement by ha is 12 000 m3
for a cropping intensity of around 150%). This is almost the same volume estimated by the
first method.
Groundwater modeling scheme for the target zone
Increasing and often competing demands between agricultural and municipal sectors on
the ground-water resources are creating a need for improved scientific information and
analysis techniques to better understand and manage ground-water systems. Numerical
simulation models became important tools for the assessment of ground-water flow
systems and ground-water development strategies. Commonly, these models are used to
test specific water-resource management plans, or, in a trial and-error approach, to select a
single plan from a few alternative plans that best meets management goals and constraints.
The main objective of ground-water flow models is to provide a quantitative and
qualitative assessment of ground-water resources in the water supply well field... The
model is a valuable tool for (1) estimating ground-water recharge, discharge, and storage at
spatial scales; (2) assessing the cumulative effects of existing and proposed water resource
uses and developments; and (3) evaluating the cumulative effects on water resource of
various water management options. Because of the complex nature of ground-water
systems, however, and the large number of engineering, legal, and economic factors that
often affect ground-water development and management, the process of selecting a best
operating procedure or policy can be extremely difficult. To address this difficulty, ground-
water simulation models have been linked with optimization-modeling techniques to
determine best (or optimal) management strategies from among many possible strategies.
Optimization models explicitly account for water-resource management objectives and
constraints, and have been referred to as management models. The use of combined
simulation-optimization models greatly enhances the utility of simulation models alone by
directly incorporating management goals and constraints into the modeling process. In the
simulation-optimization approach the modeler specifies the desired attributes of the
hydrologic and water-resource management systems (such as maximum allowable ground-
water level declines and safe yields ) and the model determines, from a set of several
possible strategies, a single management strategy that best meets the desired attributes. In
some cases, however, the model may determine that none of the possible strategies are able
to meet the specific set of management goals and constraints. Such outcomes, while often
not desirable, can be useful for identifying the hydrologic, hydro geologic, and
management variables that limit water-resource development and management options.
Because of their usefulness for evaluating complex hydro geologic and water-resource
management systems, simulation-optimization models have been developed to assess
various types of local ground-water management problems, such as
Ground-water-level declines and aquifer-storage depletions
Conjunctive use of ground-water resources
Ground-water contamination
Simulation optimization models should be applied to the important ground-water
productive aquifers as High-yielding sandstone and alluvial aquifers which are important
source of water in Ahwar area. Processing ModFlow of United States Geological Survey
could be as a useful tool to simulate the conditions of groundwater /water quality in the
study area. The groundwater flow models should be constructed for the detailed study for
this project and be calibrated in steady state conditions by matching the static water table
with the modeled water level. The model should be calibrated in transient flow by
matching the measured draw down (due to abstraction from the well fields) with the
modeled draw down.
A groundwater model should be applied to investigate the groundwater level fluctuations
and fresh-seawater relations in an unconfined coastal aquifer which could be form as a
result of land reclamation. The aquifer could be subject to appropriate open boundaries.
Groundwater level fluctuations at the site should be measured at least on weekly basis at a
number of observation standpipes. Hydraulic conductivity values for the site should be
estimated from a tidal influence constant hydrogeological parameters should be applied
throughout the aquifer.
The results obtained could verify whether the aquifer is homogenous or non homogenous.
The simulated head values should generally fit with the observed groundwater levels. The
simulated and observed groundwater flows radiate to the groundwater decline at the centre
of aquifer from the shorelines where the saturated thickness is the smallest. The model
should also able to estimate the increase in aquifer salinity due to abstraction.
Vertical salinity anomalies should be clarify the salinity stratification status and salt water
intrusion, high salinity water at the bottom water column and low salinity at the surface.
And to simulate the groundwater major vertical density differences related to distribution
of water temperature vertical variation. The groundwater scenarios and other simulation
works for AHWAR area should be seated in cooperation with modular and other study
team members at the detail design stage to serve the general model scheme for the targeted
zone is detailed in the Model Scheme ( Annex I)
8.0 GROUNDWATER BALANCE
After the understanding the groundwater flow pattern in Ahwar area, water balance could
be calculated taking into account all identified groundwater sources. AHWAR Delta
consists of the flood plain of Wadi Ahwar. The plain consists for the most part of alluvial
fan areas which, are mainly developed for groundwater agriculture, near the foothills in the
east rain fed agriculture and some hills runoff agriculture take place. Spate irrigation can
be found along upper streambed of the Wadi, groundwater irrigation mainly concentrated
at the center of. Ahwar plain. Except for some runoff from hill slopes in the foothills, no
runoff is generated in Ahwar Delta. The Delta is considered a runoff absorbing area. The
flow seeps down to the wadi courses in AHWAR area causing direct recharge to the
aquifer, the annual average wadi flow of (65.8 Mm3) causing direct recharge to the delta
aquifer system. The estimated amount of annual recharge through wadi flow is presented in
the runoff water balance sheet.
Despite of upstream spate irrigation, large surface flow is still available at wadi Ahwar
delta. While groundwater natural inflows to the basin are increasing gradually with
groundwater slope and the slope increases together with drawdown and /or abstraction
from the basin, the inflows then were calculated as percentages from the actual abstraction,
more abstraction means more irrigation and more return flow. The total abstraction was
calculated at 24 Mm3 according to the analyzed results of the surveys conducted by the
project. .
The annual rainfall in the area varies between 60 mm along the coast and 100 mm at the
edge of the foothills. The average rainfall is in the order of 80mm. The direct recharge
from rainfall was estimated to 5% of the average rainfall or 0.6 MCM of direct recharge
over the study area. This amount was not considered in the water budget.
The groundwater loss by evaporation is considered equal to 9.7 Mm3. This is based on
Kazgiprovodkhoz Institute (1990) evaluation.
Irrigation return flow coefficients, is the ratio between the quantities of water returned
from the cultivated area to the groundwater system and the amount of abstraction is
considered equal to 25% of the total amount of irrigation water diverted through spate
irrigation.
Groundwater level elevations in AHWAR area have dropped down in many places forming
depleted cones. The groundwater flow pattern has been changed and lateral flow has
occurred. Based on the depleted cones, this lateral flow was calculated at 3 % of the total
annual abstraction. This figure was driven from Darcy’s law. Groundwater approximate
gradient and aquifer permeability estimated at 6m/d, based on pumping tests results, and
assuming an average saturated thickness of 30 m of the aquifer in the north and 15m in the
south.
The detailed groundwater budget for the period 1999 to 2007 is provided in table 9.1
below.
The ground water yearly deficit is about 15 Mm3 annually, the deficit is accumulated
yearly, and increasing water abstraction will lead to more groundwater depletion and will
invite seawater intrusion.
The safe yield of the groundwater system is estimated at 18.66 Mm3
Table 2.3 Groundwater budget Wadi Ahwar *)
Year Runoff Irrigation
from Irrigation
to ground
water
Wadi loss
to ground
water
Lateral
inflow
Total IN
(4+5+6)
Abstrac-
Tion
Evapora-
tion
total OUT
(8+9)
Yearly balanc
e
(7-10)
1 2 3 4 5 6 7 8 9 10 11
1999 101.12 56.01 14.00 11.79 0.72 26.51 24.00 9.70 33.70 -7.19
2000 50.50 39.54 9.88 5.54 0.72 16.14 24.00 9.70 33.70 -17.56
2001 76.97 58.82 14.71 8.36 0.72 23.79 24.00 9.70 33.70 -9.91
2002 53.57 38.10 9.53 5.87 0.72 16.11 24.00 9.70 33.70 -17.59
2003 1.16 1.10 0.28 0.06 0.72 1.05 24.00 9.70 33.70 -32.65
2004 14.29 10.46 2.62 1.49 0.72 4.83 24.00 9.70 33.70 -28.87
2005 41.72 36.30 9.08 4.30 0.72 14.10 24.00 9.70 33.70 -19.60
2006 188.15 90.74 22.69 22.40 0.72 45.81 24.00 9.70 33.70 12.11
2007 64.65 47.78 11.95 6.98 0.72 19.64 24.00 9.70 33.70 -14.06
averages 10.52 7.42 18.66 33.70 -15.04
*) values in columns 2 – 11 in Million Cubic Meters (MCM)
9.0 GROUNDWATER MONITORING
9.1 Monitoring Approach
addressing monitoring frequency requirements with respect to saltwater intrusion and the
movement of salinity from the southern direction, addressing the effects of elevated iron
concentration in groundwater and the effect upon irrigation efficiency and pumping
efficiency,
The monitoring network for the Delta groundwater management unit consists of a number
of observation bores/one observation well/50km2, with a proposed bi-annual to monthly
monitoring frequency and includes two automatic data loggers.
A number of observation bores within the Delta should be specifically constructed to
locate the fresh/salt water interface and monitor the movement of the saltwater wedge.
These particular observation bores have continuously slotted casing which enables
monitoring to consist of conductivity readings recorded at 1 m intervals from the water
level to the base of the bore. The groundwater monitoring network within the Delta should
be adequate for the detection of seawater intrusion or a marked rise in the water table, and
observation bores should continue to be measured for water level, major ions, pH, and
conductivity and salinity movements.
Monitoring of water levels and complete water quality (including nutrients) is essential to
the management facilitating integration between surface water and groundwater resources,
and enabling swift management response to changes in water quality.
9.2 Groundwater monitoring network
Eight monitoring well sites were selected to reflect the actual groundwater movement,
abstraction and water quality variations, 5wells were selected along the groundwater path
from the Delta recharging point in the north to the discharging point in the south to
represent the actual ground water conditions, two wells were selected to be close to the
coast to track the water quality variation and the possible seawater intrusion, Figure 7.
Figure 7 Location of Monitoring Wells
Two other wells were selected in the eastern part of the Delta to monitor the groundwater
depletion between the pumping wells.
References
1. Ministry of Agriculture and Irrigation. “Wadi Ahwar, feasibility study”
Hydrosult INC, 2006, Ministry of Agriculture and Irrigation.
2. Ministry of Agriculture and Irrigation Integrated Rural Development project
for Middle Plateaus. “Feasibility Study for A gricultural Development in
Aryan Governorate (draft final report” March 2006.
3. Ministry of Agriculture and Irrigation General Directorate of Irrigation.
“Updating the Feasibility Study and Detailed Design, Delta Aryan Dams
project, Final Report Phase 1”, August 2004.
4. Ministry of Agriculture and Irrigation, Irrigation Improvement Project.
“Quarterly Progress January – March 2006, PIU – Tuban March 2006.
5. Ministry of Agriculture and Irrigation, Irrigation Improvement Project.
“Accumulative Report – July – June 2006, June 2006.
6. Ministry of Agriculture and Irrigation, Irrigation Improvement Project,
Project Management Unit. “Agricultural Development Component (Wadi
Zabid and Wadi Tuban) Quarterly Report January – March 2006” ,
Agronomy Consultant March 2006.
7. Ministry of Agriculture and Irrigation, Irrigation Improvement Project,
Project Management Unit. “Agricultural Development Component (Wadi
Zabid and Wadi Tuban) Quarterly Report April – June 2006, Agronomy
Consultant June 2006.
8. Ministry of Agriculture and Irrigation, Wadi Hadramout improvement
project March 2008