Ongoing Challenges in RG Basin

1. AWRA Annual Meeting: 2011 Albuquerque, NMSession: New Water Resources of NM and Obstacles to their Development 1:30 – 3:00 Monday, Nov 7 ”Economic Costs of Sustaining Water Supplies: Findings From the Rio Grande Basin” Frank A. WardNM State University College of Agricultural, Consumer, and Environmental Sciences NM Water Resources Research Institute

2. Ongoing Challenges in RG Basin • Adaptation to droughts, floods, climate change • Search for resilient water institutions where there are complex watershed processes and constraints • Agronomic • Hydrologic • Meteorologic • Economic • Political • Search for Just, Flexible, Open Water Policies • Understandable Science-informed policy

3. Road Map • Describe Potential Benefits of Comprehensive Basin Analysis (CBA) • Brief history of Rio Grande Compact • Describe principles how CBA can inform sustainable water policies. • Show how CBA can inform water sharing debates • Illustrate the use of CBA for policy analysis: sustaining RG Basin’s aquifers/reservoirs • Conclusions

4. Uses of Comprehensive Basin Scale Analysis (CBA) • CBA can provide data to inform debates on: • Adaptation to floods, drought, climate change • Ways to share transboundary waters • Irrigation water conservation subsidies • New knowledge or method (e.g., evaporation, ET) • Socially just, economically efficient, politically acceptable water infrastructure • Effective development planning • Cost effective Payment for Environmental Services

5. Simple Graphics to inform complex watershed policy debates: Sankey Chart • Watersheds are scientifically complex • Policy debates add complexity • Few simple graphics can show the choices

6. Water Balance: Rio Grande • Rio Grande from Colorado (USA) to US-Mexico border with supplies, gauged flows and depletions by location • Impacts of wet, normal, dry inflows • Must abide by existing water institutions • Rio Grande Compact • US Endangered Species Act • US Mexico Treaty of 1906 • New Mexico – Texas water sharing agreement (2008)

9. Limits of Graphics, Need for Models • Economic and policy goals: sustainability, sustainable diversion reductions, resilient institutions, minimum econ losses from drought, flood, climate change • So we use mathematical models of hydrology, agronomy, economics, and institutions for RG Basin

10. Water sharing arrangement hammered out for Rio Grande • 9 years debate, experiment, negotiation (29-38) • Signed in 1938 • Based on a creative combination of: • Observing historical use patterns • Mathematical formula for predicting historical use • Formula explained how historical use varied in wet v. dry years. • Formula was applied to share water for the future in wet and dry conditions.

11. Rio Grande Compact (Approximate) Water Sharing Formula • CO agreed deliveries to NM (1000 af/yr) • NM agreed deliveries to TX (1000 af/yr)

12. Role of CBA to Inform Water Policy Proposals • Historical outcomesby state, use, location, and period under actual water policies • Inflows: headwater supplies • Hydrologic: streamflows, reservoir levels • Agricultural: Irrigated land, farm income, yields, prodn, food self sufficiency • Urban: population, per capita use, price, supply reliability • Environmental: key ecological assets • Economic: Total economic benefits

13. Role of CBA to Inform Water Policy Proposals • Historicaloutcomesby country, use, location, and period under potentialwater policy A • Inflows: headwater supplies • Hydrologic: streamflows, reservoir levels • Agricultural: Irrigated land, farm income, yields, prodn, food self sufficiency • Urban: population, per capita use, price, supply reliability • Environmental: key ecological assets • Economic: Total economic benefits

14. Role of CBA to Inform Water Policy Proposals • Future outcomesby country, use, location, and period under actual water policies • Inflows: headwater supplies • Hydrologic: streamflows, reservoir levels • Agricultural: Irrigated land, farm income, yields, prodn, food self sufficiency • Urban: population, per capita use, price, supply reliability • Environmental: key ecological assets • Economic: Total economic benefits

15. Role of CBA to Inform Water Policy Proposals • Futureoutcomesby country, use, location, and period under potential water policy A • Inflows: headwater supplies • Hydrologic: streamflows, reservoir levels • Agricultural: Irrigated land, farm income, yields, prodn, food self sufficiency • Urban: population, per capita use, price, supply reliability • Environmental: key ecological assets • Economic: Total economic benefits

16. Use of a CBA • Impacts of alternative policy, supplies, or population by country, use, location, period. • Inflow differences: historic v potential • Hydrologic differences: historic v. potential • Agricultural differences: historic v. potential • Urban differences: historic v. potential • Environmental differences: historic v. potential • Economic differences: Benefits of new policy compared to historic policy. How these changes in benefits vary by alternative future supplies or future populations

18. Example Structure of CBA: Rio Grande Basin: CO, NM, TX

19. Objective

20. Constraints • Irrigable land, Headwater supplies • Sustain key ecological assets • Hydrologic balance • Reservoir starting levels (sw, gw) • Reservoir sustainability constraints (sw, gw) • Institutional • Endangered Species Act • Rio Grande Compact (CO-NM; NM-TX) • US Mexico Treaty of 1906 • Rio Grande Project water sharing history (NM/TX)

21. Ag water use

22. Institutions: e.g. Rio Grande Compact

23. Example Results: Rio Grande Basin • Policy 1 -- Sustain natural water capital over a 20 year period: aquifers to starting levels, no requirement for reservoirs • Policy 2 -- Increase natural water capital over a 20 year period: aquifers to starting levels, reservoirs to 90% of capacity

25. Conclusions: Overcoming Obstacles to Sustaining NM’s Water Supplies • Information Needs • Economic value of water • Agriculture • Urban • Environment • Cost of Water Conservation • Irrigated agriculture – subsidies • Urban Use -- subsidies • Water pricing: farms, cities, environment

26. Conclusions: Overcoming Obstacles to Sustaining NM’s Water Supplies • Needs for Policies/Institutions • Complete NM’s Stream Adjudications, Especially Middle and Lower Rio Grande • Build and use resilient institutions for adapting to drought, climate change