evolving thinking on agricultural water...

Evolving Thinking on Agricultural Water Productivity

Meredith Giordano Going Beyond Agricultural Water Productivity WorkshopWorld Bank, Washington DC December 8, 2014

Presentation Summary

• Water efficiency to productivity

• Areas of research

• Lessons learned

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Water efficiency to productivity: A shift in IWMI’s research focus

• Rationale: Growing demand for and competition over scarce water supplies: “How can we grow more food with less water?”

• Limitations of classical, supply driven indicators:– Focus on “losses” from storage,

conveyance, distribution, application– No distinction between “dry” and

“wet” water savings at a basin scale

Seckler, 1996

“One of the most important yet least appreciated facts about water basins is that a substantial amount of water is recycled between the sources and the sinks.”

Water efficiency to productivity: A shift in IWMI’s research focus

• Advocated improved water productivity through:– Increase output/unit of evaporated

water – Reduce losses of usable water to

sinks– Reduce water pollution– Reallocate water from lower to

higher value

Seckler, 1996 • Key considerations:– The extent to which water is

recycled in a basin– Whether a basin is “open” or

“closed”

Key areas of research

1. Terminologies and definitions.

2. Methodologies and tools to measure water productivity.

3. Applied research to understand opportunities to increase water productivity and save water.

• Classical “efficiency”– Crop ET-effective precipitation/application– Application efficiency, minimize “losses”

• Net and effective efficiency: – Address capture/re-use (and leaching requirements)

(Jensen 1967; Keller & Keller 1995)

• Water productivity:– Output of a given system in relation to water consumed– Multiple uses and sequential re-use within a basin– Multiple sources of water – Multiple scales

1. Terminologies and definitions

Basic Expression: WP = output/water consumed

Variations

Cook et al. 2006

Molden et al. 2010

Molden et al., 2010

1. Terminologies and definitions

2. Methodologies and tools: Water accounting

How much water is actually depleted, where and for what use, compared to that available and the portion diverted?

Molden, 1997

Molden, 1997

• Identifies total water depletions.

• Distinguishes between process and non-process depletions.

• Estimates low or non-beneficial depletions.

• Accounts for downstream commitments.


Turral, 2006

2. Methodologies and tools: Modeling/RS

Crop WP, Indo-Gangetic Basin

Cai et al. 2010

• Estimate average current and potential water productivity.

• Target locations where large improvements in water productivity are possible.

• Identify entry points to improve water productivity, generate real water savings.

• Understand the potential consequences.

Turral, 2006

2. Methodologies and tools: Modeling/RS

WP GVPet

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2.000

4.000

6.000

8.000

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WP in subdivisions of Rechna Doab

Ahmad, 2004


WP GVPet

0.000

2.000

4.000

6.000

8.000

10.000

12.000

Malhi

Nokh

ar

Sagar

Sadho

ke

Gujjra

nwal

a

Shahd

ara

Chuh

arka

na

Naus

hera

Sangla

Mur

idke

Pacca

dala

Sheikhu

pura

Kot k

huda

yar

Sikha

nwala

Uqba

na

Moh

lan

Amin

pur

Wer

Buchia

na

Verya

m

Man

gtan

wal

a

Tandilia

nwala

Dhau

lar

Tarkh

ani

Kanya

Have

li

Bhaga

t

Sulta

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Sub-division

$/m

3

WP in subdivisions of Rechna Doab

If we know why the values are low or high, then we can determine whether WP can be improved and how, by, e.g.• Increasing productivity per unit of water

consumed. • Reducing non-beneficial depletion.• Reallocating water among uses.• Tapping uncommitted outflows.

Ahmad 2004


3. Applied Research: Water productivity in context

• Water productivity across time and space

• Impact of interventions on conservation goals and other development objectives

3a. Applied research: Water productivity and place

Crop water productivity, 10 Basins (figures below from Nile and Indus-Ganges basins)

High water productivity levels in one region may be indicative of what is possible, but…

Cai et al., 2011

3a. Applied research: Water productivity and place

Key finding: Water productivity values and pathways for improvement must be understood within their specific setting.

…location specific factors must be considered.

Effect of milk production on rice WP, Krishna Basin, India

Krishna Basin, 2004

Biggs, 2004

3b. Applied research: Water productivity and perspective

Liuyuankou Irrigation System (LIS), Yellow River

Molden et al., 2007

Zhanghe Irrigation System (ZIS), Yangtze River

Two systems, two opportunities (to improve WP), two different outcomes.

Adapted from Molden et al. 2007

Incentives and pressures to save or reallocate water by user group and scale

Adapted from Molden et al. 2007

3b. Applied Research: Water productivity and perspective

Key finding: Policies and strategies for changing water use and management must aim to align the objectives and incentives across user groups/scales, to obtain society-wide goals for improved water use.

3c. Applied research: Water productivity and water savings

Key finding: Even when technologies decrease applications per unit of crop output, they may not decrease actual water consumption (in fact may increase) unless institutional arrangements are in place to limit demand or reduce available water.

Ahmad et al., 2006

Rice-Wheat Zone, Punjab Province, Pakistan

3d. Applied research: Water productivity and poverty

Key finding: There is no simple link between water scarcity, poverty and equity. It is more relevant to understand the influence of water-related variables on poverty together with the livelihood strategies and institutional capacity to manage trade-offs.

Development Trajectory, 10 Major River Basins

Kemp-Benedict et al., 2011

“WP interventions can either reinforce or reduce inter-household inequities.”

“Identifying pre-existing inequities in water access within and among communities will support better targeting of poor communities”

Water Productivity and Poverty, Ganges Basin

Clement et al., 2011

• The concept of water productivity fostered a move from a theoretical discussion on the need to produce more food with less water to a practical discussion (should, where, why, and how?).

• Proper water accounting is fundamental.

• Water productivity is not a goal in and of itself.

• It is one of many factors involved in improving agricultural productivity and supporting poverty alleviation, food security and ecosystem functioning.

• Single indicators can mask the complexity and trade-offs required to achieve development outcomes.

Key Lessons

“The aim of the workshop is to reach more clarity -- and possibly a more integrative view -- on "agricultural water productivity" and, most likely, broader approaches to help address rising water and food security concerns.”

Thank you

Ahmad, M.D., et al. 2004. “A comparative analysis of crop water productivity of rice-wheat and cotton-wheat rotations in

Rechna Doab, Punjab, Pakistan”. New directions for a diverse planet. In 4th International Crop Science Congress.

Ahmad, M.D., et al. 2007. “Water saving technologies: myths and realities revealed in Pakistan's rice-wheat systems.

IWMI Research Report No 108 (IMWI)

Cai, X.; et al. 2010. An assessment of crop water productivity in the Indus and Ganges river basins: Current status and

scope for improvement. Colombo, Sri Lanka: International Water Management Institute. 30p

Cai, X., et al. 2011. “Producing more food with less water in a changing world: assessment of water productivity in 10

major river basins.” Water International 36(1): 42-62.

Clement, F., et al. 2011. “Enhancing water productivity for poverty alleviation: Role of capitals and institutions in the

Ganga Basin.” Experimental Agriculture 47(S1): 133-151.

Jensen, M.E. 1967. Evaluating irrigation efficiency. Journal of irrigation and Drainage 93(IR1):83–98

Jensen, M.E. 1977. Water conservation and irrigation systems. In: Climate-technology seminar proceedings, Colombia,

Missouri, 25–26 October 1977, pp 208–250

Keller AA, Keller J. 1995. Effective efficiency: a water use efficiency concept for allocating freshwater resources. Discussion

paper 22, Center for Economic Policy Studies, Winrock International.

Kemp-Benedict, E., et al. 2011. “Connections between poverty, water and agriculture: evidence from 10 river basins.”

Water International 36(1): 125-140.

Molden, D. 1997. Accounting for water use and productivity. IWMI/SWIM Paper No. 1, International water management

Institute, Colombo, Sri Lanka, 25 pp

Molden, D., et al. 2007. “Agricultural water productivity and savings: Policy lessons from two diverse sites in China.” Water

Policy 9(S1): 29-44.

Molden, D., et al. 2010. “Improving agricultural water productivity: between optimism and caution.” Agricultural Water

Management 97(4): 528-535.

Seckler, D. 1999. Revisiting the" IWMI paradigm:" Increasing the efficiency and productivity of water use. International

Water Management Institute (IWMI): Colombo, Sri Lanka

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