Adding a green-blue dimension to water evaluation and
planning
SEI WEAP Training Workshop 14th Dec 2004
Johan Rockström
The water sector approach
LANDSEA
110,000 km3/yr
40,000 km3/yr
Q & Q
Three decades of knowledge for Policy
KNOWLEDGE BUILDING
L’vovich 1974,79
Falkenmark, 1976
Bodyko, 1984
Shiklomanov, 1993, 1997, 2000
Gleick, 1993
UN CFWA, 1997 (SEI)
WWV, 2000
WWAP, ongoing
INTERNATIONAL AGENDA
Mar del Plata 1977
Drinking water decade 1981-1990
WCED 1987
Dublin 1992
UNCED 1992
2nd WWF 2000
WSSD 2002
WCD 2002
POLICY IMPLICATIONS
Water for Society
Sector approach to water (Dom, Ind, Irri)
Water Econ good
IWRM GWP
WSSD IWRM plans
Water for Environment
Water and Society
Sector focus
• Resource: Focus on Stable Runoff in perennial rivers, accessible groundwater and lakes
• Withdrawal: (Still not focus on use) Focus on Sectors – industry, municipal and “agriculture” (de facto large scale conventional irrigation schemes)
Freshwater assessment – the human link
Humans and Water Resources“the looming global freshwater crisis”
110,000 km3 yr-1
40,000 km3 yr-1
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1850 1900 1950 2000 2050
Wit
hd
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3 yr
-1)
Agriculture
Industry
Municipal
Total
Ceiling: 12,500 km3 yr-1
Agriculture: 69 %
Industry 23 %
Municipalities 8 %
World “freshwater” resources
Projected Blue Water Scarcity 2025 IWMI Podium analysis (de Fraiture, et al, 2000)
Water resource advancements
• Advancements in realistic withdrawals (Postel, stable and storm runoff)
• Advancements in Actual use of water – Withdrawals, Consumptive use, Efficiency (irrigation “use” goes down from over 2500 km3/yr to 1800 km3/yr) (Seckler, Shiklomanov, and others)
• Advancement of IWRM concept, planning tools (GWP Toolbox, WaterNet, CapNet….)
• Water Security, Transboundary waters – Water wars (Aaron Wolf, world map of transboundary waters – no war has started due to water….)
• Water demand management (GWP, Think tanks, NGOs)• Hydrosolidarity (Upstream/downstream sharing of finite water
(Jan Lundqvist)• Water and Sanitation
Environmental Water FlowsGetting water for nature into the water for
food and people picture
Jackie King
Smakhtin
J F M A M J J A S O N D
Ave
Dis
char
ge
High
Low EFR for river
Sustainable use focus Water for storage
J F M A M J J A S O N D
Ave
Dis
char
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LowAve
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char
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High
Low EFR for river
Sustainable use focus Water for storage
Natural
J F M A M J J A S O N D
Ave
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Low
Natural
J F M A M J J A S O N D
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LowAve
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Water supply focus
J F M A M J J A S O N D
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LowAve
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Water supply focus
J F M A M J J A S O N DJ F M A M J J A S O N D
Virtual water and Virtual water trading
Allan, 1995
Oki Taikan, 2000
Arjen Hoekstra, 2002
…
Open, closing, closed basins
Basin state Excess water Increased consumptive use
Examples of eco-hydrological
indicators Open Always Possible 30 % of stable
runoff secured for ecosystems Natural fluctuations of riverflow
Closing Only during wet season
Possible only during wet season, requires new storage
Storage and diversions of river flow result in changes in river flow regime < 30 % of stable runoff secured for ecosystems
Closed Never Only by reallocating water from other consumptive uses
River flow not enough to sustain in-stream ecological functions.
So, where are we in understanding water for life support in mainstream water policy?
IWRM principle for River Basin Management
Water Consumption
EWF, Storm flows, riparian zones, estuaries
Virtual water trading (25% driven by water scarcity)
WDM, Q&Q Urban
Water and Megacities
Water conflicts
Green water enters the scene…
Malin Falkenmark, 1995
The Terrestrial hydrological cycle (L’vovich data)
The water consumed in the production of vegetation on fields, which are not irrigated, is not given attention in practical water management at the present time. There is no basis whatsoever for such an approach except perhaps that this expenditure of water takes place imperceptibly (water is not actually pumped from streams and aquifers, as is the case in irrigated agriculture) (L'vovich 1974, p 316)
As is frequently done in hydrology, the losses [referring to the difference between rainfall and observed surface runoff] include the water that goes to infiltration, evaporation from the soil, and the feeding of groundwater; this conforms with the conception that regards only river water as useful. In actuality, if we assess the importance of all the elements of the water balance and do not regard river water as the most important link in the water cycle, though indeed an important one, the losses should consist of surface runoff, which represents a loss of water for the given area. At the same time, soil moisture, as one of the components of soil fertility from the standpoint of human interest, is a more important element than river water. (L'vovich, 1974, p 36)
Rainfall partitioningsemi-arid rainfed farm land in sub-Saharan Africa
Advancements in SWAP interface research
-ET to E + T (Sapflow)
- The role of Vapour always known…..
Understanding of water for life support develops
• 1st green water ecological footprint (Jansson,Å, Folke, C, Rockström, J & Gordon, L (1999) Linking freshwater flows and ecosystem services appropriated by people: The case of the Baltic Sea drainage basin. Ecosystems, 2:351-366)
• Stockholm Water Symposia (SIWI, 2000, 2001, 2002, 2003, 2004, 2005)
Human Water Dependence
The eco-hydrological perspective
Eco-hydrological approach to water resource
ECOSYSTEM FUNCTIONS
Aquatic freshwater habitats
Biodiversity, Resilience
ECOSYSTEM BIOMASS GROWTH
Plants and trees in wetlands, grasslands, forests and other biotopes
Biodiversity, resilience
INDIRECT
ECONOMIC USE IN SOCIETY
Irrigation, Industry and Domestic uses
ECONOMIC BIOMASS GROWTH
Rainfed food, timber, fibres, fuelwood, pastures, etc.
DIRECT
BLUEGREENWater Flow Domain
Use Domain
Human Dependence on Vapoura bottom-up estimate
Rockstrom, J., Gordon, L., Folke, C., Falkenmark, M., and Engwall, M., 1999. Linkages among water vapor flows, food production and terrestrial ecosystem services. Conservation Ecology, 3(2) : 5 [online] URL: http:\\www.consecol.org/vol3/iss2/art5
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
Low Mean High
km
3 y
r-1
Forest
Grasslands
Agriculture
Wetlands
The blue concern
40,000 km3/yr
12,500 km3/yr
27,500 km3/yr indirect Blue
7,500 km3/yr
5,000 km3/yr (40%), Environmental Flow and Navigation
5,250 km3/yr
2,250 km3/yr (30 %), Flushing of nutrients
The global Water Foot Print
Direct Green 22 %
Indirect Blue 35 %
Direct Blue 2 %
Indirect Green 41 %
World map of Green and Blue water dependence in food production
Quantifying the challenge
Water for food in 2050
Water for food challenge
Water requirement
2050
(km3/yr)Current food from crop land (year 2000) 7000
Eradicate current malnutrition
to Desired (1300 m3/cap/yr) 2222
Food for additional population 2050
UN Medium [9.3 billion] 3364
Total 12586
Where will the water come from?
Water for food 2050 12,600 km3/yr
Present water for food
7,000 km3/yr
Additional requirement
5,600 km3/yr
Irrigation contribution
800 km3/yr
Rainfed contribution
4,800 km3/yr
Water Dev 600 km3/yr
Water Productivity 200 km3/yr
Water for dietsProjection 2050
Freshwater Predicament 2025 and 2050 for the Tropical hotspots
450 km3/yr
2300 km3/yr
1500 km3/yr
North Africa/Middle East x 1.8
Central America x 0.8
North America x1.6
South America x1.7
Europe x0.9
2800 km3/yr
6400 km3/yr
5700 km3/yr
Sub-Saharan Africa
Asia
At present Globally 7,000 km3/yr
Addressing Trade-offs
Recent advances in Green water estimates
• Charles Vörösmarty, global freshwater assessment at finer resolution – (Vörösmarty,
C.J., Green, P., Salisbury, J., and Lammers, R.B., 2000. Global water resources: Vulnerability from climate change and population growth. Science, 289 : 284 – 288)
• Green water estimates at system scale (irrigation schemes, watersheds) (Bastianssen, Droogers, Jos van Dam)
• SEI – SSI research – Scintillometer, remote sensing, sap flow – from farmer field to catchment scale
The 1st integrated water resource assessment
Water Trade-offs and the UN MDGs
FLOW OPTION IMPACT
GREEN GROWTH
(4800 km3/yr)
EXPANSION
Land use change
System Trade Offs (Rfunctional shifts of rain)
PRODUCTIVITY Blue Water Reduction (?)
BLUE GROWTH
(800 km3/yr)
INSTREAM ECOLOGY System Trade-offs
PRODUCTIVITY Downstream flow reductions (?)
Taking on vulnerability and climate change
• Going from blue to green-blue
• Incorporating surprise, shock and the vulnerability dimension of freshwater
• Incorporating climate change as a driver of vulnerability
Climatic Variability – The entry point
Rural Livelihoods
Local Water and Food security
Adapting to climate change induced variability
Untapped potential of managing inherent climatic variability
Managing the manageable part of
inherent climatic variability
Upgrading rainfed agriculture in regions subject to high climatic variability
Implications for Evaluation and planning
• Multiple scale interactions
• Spatial landscape mosaic as a key to resilience
• The role of green water flow in sustaining ecosystem functions
• The dynamics of green water flows for biomass production
• Feedback loops
Multiple scale interactions
Australia – Golden BrokenTanzania - Pangani
2 7 ° E 3 0 ° 3 3 °
2 1 ° S
2 4 °
Ind ianO ce an
M w e n e z i
Limp op o
M o t lo u ts e
S h a s h e
T u l i
B u b y e
C h a n g a n e
Olifan ts
G re a tL e t a b a
M id d leL e t a b a
N g o t w a n e
M a r ic o
C r o c o d i le
M o k o lo
L a p h a la la
M o g a la k w e n a
S a n d
B ly d e
R e i t
W i lg e
E la n d s
P ie n a a r s
L e v u v h u
L o ts a n e
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Mean AnnualRainfall (mm)
1250
N
S e la ti
U m zin g w a n i
L i t tleO l i fa n ts
S te e lp o o rt
S h in g w e d z i
0 50 100 150 200 km
ZIMBABWE
MOZAMBIQUE
MOZAMBIQUE
BOTSW ANA
SOUTHAFRICA
Mzingwane
Oliphants
Chokwe
Multiple scale interactions – the partitioning dilemma
Management innovations A Nested Scale Approach
”100 % yield increase potential in rainfed farming systems compared to a 10 – 15 % increase potential in irrigated systems” Pretty and Hine, 2001
Spatial Landscape Mosaic – its role for resilience building
The role of green and blue water flows in sustaining resilience The Pangani Basin, Tanzania – The SSI program
Dynamics of Green water flows
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ater
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WP~1500 – 3000 m3/ton
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Dynamic relation between yield and water productivity
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Yield (t/ha)
Water pro
ductivity (m
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Pandey et al.
Dancette, 1983
Stewart et al., 1975
Rockstrom et al., 1998
efficiency ofproductivegreen water
green waterproductivity
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Grain Yield (t/ha)
WP
ET (
m3/t
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Non Irrigated Wheat
Irrigated Wheat
Non Irrigated DurumWheat
Irrigated Durum Wheat
)(1 bYT
ETeWP
WP
Implications for WEAP modelling
• Quantifying multiple functions of water in supporting ecosystem services and resilience (green/blue, direct/indirect)
• Incorporate scale dynamics – nested scales, scaling in-out, landscape mosaic, spatial flow distribution)
• Represent soil moisture, vapour shifts, green water flows for different systems and management
• Enable the model to analyse options and effects of innovations in water management at the small scale
• Incorporate elements of risk, vulnerability, ecological resilience and feedback loops !...
• ..in essence – how to develop a distributed and dynamic hydrological model, representing the water balance at local scale and its relation to larger scales, while still maintaining a simple tool for policy and planning – i.e., using a simple approach to capture complexity without being simplistic.
• Albert Einstein’s famous dictum “Make it as simple as possible, but not simpler”
• Consequence?The dynamic relationship between Y and WP suggests that every change
in management, changes the green water relationship…
…i.e., to know your virtual water you need to know the yield and management practices used by the farmer…
Water Productivity
Strategy
Flow source
Flow in Fig.7.9
Estimate reduction in green water
requirements (km3/year)
Process Management
Vapour shift (E to T shift)
(A) Reduce early season E
In-field evaporation
[I] 120 Evaporation reduction
Early sowing Intercropping
(B) Reduce E with increased canopy
210 Crop Soil fertility Mulching
Productive use of local runoff
Off-field surface runoff
[II] 300 Runon surface runoff converted to green water flow
Water harvesting for dryspell mitigation
Green water productivity improvement (T/ET ratio increased)
Off- field surface runoff, deep percolation
[II] & [III] 900 Increased plant water uptake
Soil and water conservation Water harvesting Crop, soil fertility management
Total
1,530 km3/year
1500 km3/yr, or 30% reduction of consumptive use….
3,300 km3/yr remains…
But, the linear relationship between productive green water flow and yield should hold (resulting in constant WPT for given agro-ecological conditions)
Productive green water productivity
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Grain maize yield per season (t/ha)
Sea
son
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SI LR SI SR
NI LR NI SR
APSIM Modelling Maize, Mwala, Kenya (20 years)
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Productive Green cont…
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farmers' practice
SI + Low Fert
APSIM Modelling Maize systems in Zimbabwe
Implications for balancing
Dynamics of Green water productivity
Dynamics of Productive Green water productivity
Management
Balancing water for ecosystem functions
Management innovations A Nested Scale Approach
”100 % yield increase potential in rainfed farming systems compared to a 10 – 15 % increase potential in irrigated systems” Pretty and Hine, 2001
Green water momentum
• ISRIC Green water initiative• FAWPIO Forest and green water• IFAD – green water trading, green water
services• WB – green water management for
livelihoods• GWSP – regional and global functions of
green water flows• VIEWS – wider links between GEC,
Vulnerabilty and water system services
Defining a new Dynamic Green-Blue water framework for IWRM
• Firmly advancing the role of water for sustainability – The role of Green and blue water flows for ecological functions and system services
• Freshwater, risk and vulnerability/resilience• Freshwater and climate change• Adding a dynamic water productivity dimension – more food
does not “simply” mean more water• Scale interactions of water functions (water and livelihoods,
water and land use – degradation/carbon sequestration/nutrient cycles)
• Water services provided through land and water management• Define a new Water Policy agenda – start by answering the
question – When does rain turn into Water? and Who owns the rain?
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