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Addressing Climate Change in Local Water Agency Plans

Addressing Climate Change in Local Water Agency Plans: Demonstrating a Simplified Robust Decision Making Approach in the California Sierra Foothills

David G. Groves
Evan Bloom
David R. Johnson
David Yates
Vishal Mehta
Copyright Date: 2013
Published by: RAND Corporation
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  • Book Info
    Addressing Climate Change in Local Water Agency Plans
    Book Description:

    This report describes an approach for planning under deep uncertainty, Robust Decision Making (RDM), and demonstrates its use by the El Dorado Irrigation District (EID). Using RDM, the authors and EID tested the robustness of current long-term water management plans and more robust alternatives across more than 50 futures reflecting different assumptions about future climate, urban growth, and the availability of important new supplies.

    eISBN: 978-0-8330-8255-8
    Subjects: Political Science, Physics

Table of Contents

  1. Front Matter
    (pp. i-ii)
  2. Preface
    (pp. iii-iv)
  3. Table of Contents
    (pp. v-vi)
  4. Figures
    (pp. vii-viii)
  5. Tables
    (pp. ix-x)
  6. Summary
    (pp. xi-xviii)
  7. Acknowledgments
    (pp. xix-xx)
  8. Abbreviations
    (pp. xxi-xxii)
  9. 1. Introduction
    (pp. 1-2)

    Water agencies have always faced uncertainty when developing programmatic plans and constructing infrastructure. Never certain as to the hydrologic conditions in the coming years, they make educated guesses based on historical observation. They plan in advance for future water needs by estimating future water demand and then using these estimates to determine necessary infrastructure and changes in programs. Today’s water agencies use computer models of their systems to calculate future water supply, demand, and infrastructure needs. Mindful of the effects that new investments have on the water rates they must charge their customers, they seek solutions that will ensure reliable...

  10. 2. An Approach for Addressing Climate Change by Local Water Agencies
    (pp. 3-8)

    Figure 2-1 illustrates the steps of an emerging paradigm for addressing climate change in long-term natural resource plans (National Academy of Sciences: Committee on America’s Climate Choices, 2011). It describes a series of iterative steps in which risks and options are evaluated; near-term decisions are made and implemented; and conditions are monitored to help refine plans over time. This approach recognizes that any robust plan that addresses climate change will need to be adaptive over time. There is, however, no single accepted approach for assessing, identifying, and appraising options and then making a decision based on this information (Steps 3-6)....

  11. 3. Application to Local Water Agency Planning
    (pp. 9-24)

    This study demonstrates the use of RDM for incorporating climate change into the long-term planning of a California local water agency—EID, which lies within El Dorado County on the west slope of the Sierra Nevada Mountains (Figure 3-1). The east end of the county lies in the Sierra Nevada Mountains, where winter snow accumulation and spring and summer snowmelt constitute an important element of the regional hydrology. The western end of the district is characterized by increasing suburban and peri-urban development. In between these two extremes, the main rivers of El Dorado County run through deep, picturesque canyons where...

  12. 4. Results
    (pp. 25-46)

    In this section, we describe the results of the RDM analysis, addressing key questions that follow the iterative, analytic RDM steps shown in Figure 2-2:

    How reliable is EID’s current plan under standard planning assumptions? (Step 2)

    How reliable is EID’s current plan under alternative but plausible assumptions about the future? (Step 2)

    Under what conditions is EID’s current plan most vulnerable? (Step 3)

    How can EID’s vulnerabilities be reduced through additional management options? (Steps 2 and 3)

    What are the key tradeoffs among EID’s strategies for reducing its vulnerability? (Step 4)

    How can expectations of the future inform decisions?...

  13. 5. Discussion
    (pp. 47-50)

    This study illustrates how RDM can be used in water agency planning to consider climate and other deep uncertainties. In this case, the study considers uncertainty about future climate and hydrologic conditions, urban growth rates, and success in developing a new, large water supply. The approach can be easily expanded to consider many more uncertainties of concern.

    A key feature of this approach is the use of simulation models to estimate future outcomes for a baseline strategy and proposed alternative strategies under a large set of future scenarios that capture a plausible range of future conditions. Rather than assigning probabilities...

  14. References
    (pp. 51-54)