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

0

1000

2000

3000

4000

5000

6000

1850 1900 1950 2000 2050

Wit

hd

raw

als

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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

ge

High

LowAve

Dis

char

ge

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

Dis

char

ge

High

Low

Natural

J F M A M J J A S O N D

Ave

Dis

char

ge

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LowAve

Dis

char

ge

High

Low

Ave

Dis

char

ge

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Low

Water supply focus

J F M A M J J A S O N D

Ave

Dis

char

ge

High

LowAve

Dis

char

ge

High

Low

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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Yield (t/ha)

Gre

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ater

flo

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WP~1500 – 3000 m3/ton

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Emerg Veg Flower Mature

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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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n)

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

on

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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

al t

ran

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atio

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)

SI LR SI SR

NI LR NI SR

APSIM Modelling Maize, Mwala, Kenya (20 years)

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Grain maize yield per season (t/ha)

Sea

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Productive Green cont…

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Grain Yield (kg/ha)

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m)

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?