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Suzanne A. Pierce

Problem formulation: Recognizing attributes that lead to practical alternatives. Suzanne A. Pierce. (Photo courtesy of Austin History Center, PICA17272). Available Yield. The volume of water that can be removed from and aquifer while: Staying within natural recharge rates

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Suzanne A. Pierce

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  1. Problem formulation: Recognizing attributes that lead to practical alternatives Suzanne A. Pierce (Photo courtesy of Austin History Center, PICA17272)

  2. Available Yield The volume of water that can be removed from and aquifer while: • Staying within natural recharge rates • Preserving economic viability • Avoiding negative water quality and quantity impacts • Complying with legal constraints • Protecting intergenerational equity

  3. Case Study: Barton Springs segment Edwards Aquifer N ~5mi • Well studied karst aquifer • Rapidly growing urban area • History of community conflict ~5mi About 25% of the world’s population depends on karstic water supply 40% of the United States uses water from karstic areas.

  4. Identifying Stakeholders: Regional Water Quality Planning The preference sets held by stakeholders define an acceptable range of policies for extraction • A completed report from the RWQP Stakeholder Process • 10 stakeholders agreed to participate in research • Developer, • Environmental, • Government agency, • Economic interests • Property rights, • Concerned citizen, and • Scientists • Getting the Developers to the Table – new participant • Potential for Implementation via HB 1763

  5. What tools available to build consensusTask for stakeholders A platform unsuited to answer management questions alone Groundwater Availability Models (GAM)

  6. The Aquifer Yield Continuum Risk Seeking Unobtainable Minable Ideal condition response to pumping Community Tolerance for Risk (Utility) Total Aquifer Storage Risk Averse Replenishable Increased Pumping Sum of all non-consumptive flows Annual average recharge

  7. Ranges of Stakeholder Positions Risk Seeking Unobtainable Minable Community Tolerance for Risk (Utility) Total Aquifer Storage Stakeholder position Consensus space Risk Averse Replenishable Increased Pumping Sum of all non-consumptive flows Annual average recharge

  8. Open ended elicitation (Amy Coren, unpublished)

  9. Elicitation for Science Models Natural Attributes for an Aquifer System • Pumping • Spring flow • Storage • Saturated thickness • Water table elevation • Recharge (relevant to the Barton Springs Case)

  10. Results of elicitation

  11. Results of elicitation

  12. Representing values in the model Water Budget Saturated Thickness Spring flow Objective 1 – Maximize total pumping (Photo by Greg Eckhardt) Objectives 2 & 3 – Maximize minimum spring flow (Photo by BSEACD) Objective 4 & 5 – Maximize Average Storage Where 0 if b >100 feet 1 if b ≤ 100 feet Qai,j= Objective 6 – Optimizes land use distribution as a recharge function To retain simplicity of problem presented here, this aspect will not be discussed.

  13. Decision variables in the model Drought Triggers Spatial Relocation & Addition of Pumping • New Pumping equally divided • Search determines best re-allocation Drought Settings • % conservation measures expected of permittees

  14. Generating Alternative Set TABU’s memory system. . .is analogous to human memory process. GWDSS uses MASTS - A TABU search engine developed by Michael Ciarleglio, unpublished

  15. Selecting a set of alternatives to evaluate 63 alternative set selected for consideration Chosen for following reasons: • Maximizing Total Pumping • Generated ~385 alternatives • Removed alternatives that were equivalent • Included full range of alternatives across outputs (ie. min – max for all measured outputs included)

  16. From Objectives to Attribute Selection Need to be essential broadens Need to be controllable narrows Fundamental Objectives Alternatives Strategic Objectives (from Keeney,1992)

  17. Goals Hierarchy

  18. Version 1 – Volume-based Attributes

  19. Version 2 – Count-based Attributes

  20. Comparing Rankings #4 #4 Volume-based Metrics Count-based Metrics #34 #34

  21. Stakeholder Profile: Priority Listing Total Extraction Drought Policy Well Reliability Storage Spring Flow Impervious Cover Water Budget Groundwater Conservation District – Brian Hunt X 4 5 Aquifer Performance 3 6 9 2 Increased pumping in Zones 10, 1, and 4 favors increased spring flows at Barton Springs 10 1 8 7 11 N Objective: Constraints: Scenario Settings: Maximize Total Pumping Community Driven, Existing Legal Permits Dry Climate, Growth Scenarios, Well Relocation Photo by Gregg Eckhardt

  22. Ranking a Single Objective Maximize Pumping Volume (From Volume-based Metrics)

  23. Stakeholder Profile: Priority Listing Spring Flow Impervious Cover Storage Drought Policy Well Reliability Total Extraction Spring flow Environmentalist – Jon Beall Values & Tradeoff Curves Spring Flow to Impervious Cover 50 Q (Billion ft3/month) 0 1922 2002 Physical System Preference System Objective: Constraints: Scenario Settings: Maximize Spring Flow Low Impervious Cover, High Drought Reductions Conservative Urban Growth, Dry Climate

  24. Single Objective Ranking should be simple . . . Right? Maximize Average Spring Flow Maximize Minimum Spring Flow (From Volume-based Metrics)

  25. Next Steps – Return to the stakeholders?

  26. “If there is magic on this planet, it is in water” - Loren Eiseley, The Immense Journey

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