Climate Warming & California’s Water Future

1. Climate Warming & California’s Water Future Jay R. Lund Civil and Environmental Engineering University of California, Davis http://cee.engr.ucdavis.edu/faculty/lund/CALVIN/

2. Forms of Climate Change Climate Warming and Water System Performance Concluding thoughts Overview

3. Forms of Climate Change • Sea level rise • Climate warming • Climate oscillations • Multi-decade droughts • Others?

4. Climate Warming & Water System Performance • 2100 water availability (LBNL) • Water management model for climate warming extremes

5. Inflows with Climate Warming

6. CALVIN’s Spatial Coverage Over 1,200 spatial elements 51 Surface reservoirs 28 Ground water reservoirs 600+ Conveyance links 88% of irrigated acreage 92% of population

7. Integrated Adaptation Options • Water allocation and markets • Joint surface & groundwater operations • Coordinated facility operations • Urban conservation/use efficiencies • Cropping changes and fallowing • Agricultural water use efficiencies • New technologies • Wastewater reuse • Seawater desalination

8. Water Management Objectives Environmentalflows - first priority Economic Water Uses: • Agricultural economic values • Urban economic demands (residential, industrial, and commercial) • Hydropower benefits • Operating Costs

9. 2100 Water Availability Extremes (maf/yr)

10. Climate Scenarios by Region

11. Some Early Results

12. Total Deliveries and Scarcities

13. Statewide Economic Costs($ million/yr)

14. Scarcity Costs by Sector

15. Adaptive Responses • Water transfers • Agricultural to urban • Colorado River • Central Valley • Water quality exchanges • Flexibility trading • New technologies • Wastewater reuse • Sea water desalination • Urban water conservation/use efficiencies • Groundwater reservoir use • The mix of responses is important.

16. Economic Value of Facility Changes($/unit-yr)

17. Environmental Flow Costs

18. Conclusions from Results • Climate warming can be wetter or drier overall, with seasonal flow shifts. • Central Valley agriculture is most sensitive to dry climate warming. • Flooding could be very challenging and costly. • California’s system can adapt, at some cost, if it has institutional flexibility.

19. What to do now? • Long-term importance of flexibility • Integrated mix of management options: Water use efficiency, conjunctive use, water transfers, reuse, desalination, storage … • Importance of local and regional actions in a statewide context • Enhance ability to cooperate at local, regional, and statewide levels to gain from the richness and strengths of our water system.