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Transcript of Evolving Thinking on Agricultural Water · PDF file Evolving Thinking on Agricultural Water...

  • Evolving Thinking on Agricultural Water Productivity

    Meredith Giordano Going Beyond Agricultural Water Productivity Workshop World 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.

    2. Methodologies and tools: Water accounting

  • 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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    Sub-division

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    WP in subdivisions of Rechna Doab

    Ahmad, 2004

    2. Methodologies and tools: Water accounting

  • WP GVPet

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    Sub-division

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    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

    2. Methodologies and tools: Water accounting

  • 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