1. California's Delta and the Future of State-scale Water Supplies Mike Dettinger USGS/SIO

2. California's Water Supplies http://www.water.ca.gov/maps/allprojects.html 75% of runoff occurs in north 72% of consumptive use in south Sacramento-San Joaquin Delta & Watershed

3. Agriculture Urban Uses of the Major Water Projects

4. Water Sources for Urban Southern California Delta Metropolitan Water District Urban Water Management Plan, 2005 New CR Xfers

5. Sacramento R San Joaquin R Delta Bay NORTH In today's State-scale water-supply system, the Delta is the critical, but weak, link between North & South

6. The Delta is a 2200 km 2 maze of FarmsFarms Channel & sloughsChannel & sloughs MarshlandsMarshlands SuburbanSuburbanEncroachment …all sitting very near sea level with water held in place by aging, poorly engineered levees 50 km

7. Delta as the North- South Meeting Place of Waters Low quality San Joaquin River High quality Sacramento River Salty seawater Water pumped south ?

8. The Big Gulp In the event of several major levee breaches, sea water is expected to flow in and cutoff passage for southbound freshwater flows to the export pumps in the southern Delta (*) Sea-level rise, increased flood flows, aging levees, earthquakes together offer an estimated 60% chance of this happening by 2050 (Mount & Twiss, 2005) Florsheim & Dettinger, 2005 The Big Gulp

9. ECOSYSTEMS Endangered fisheries, shrinking wetlands& declining landscapes have devastated the once-rich ecosystems of Central California.

10. Outflows and Diversions from the Delta

11. Slightly over 20 MAF

12. DOM in treated water ends up contaminating with byproducts like THMs (NOT GOOD!) Sources and Fates of Dissolved Organic Carbon in the Delta Luoma et al., 2008

13. Land subsidence Invasive species Population growth & urbanization Earthquakes Climate change Sea level rise Land subsidence Invasive species Population growth & urbanization Earthquakes Climate change Sea level rise Pelagic organism declines (POD) Less reliable water supplies Deteriorating water quality Threats to agriculture, communities & infrastructure corridors DRIVERS of DELTA CHANGE

14. What should the future Delta look like? Mount, Twiss & Adams, 2006

15. Business as Usual? Ecosystem's piece of the Pie?Ecosystem's piece of the Pie? Crumbling Levees & "The Big Gulp"Crumbling Levees & "The Big Gulp"

16. Fortress Delta? Astronomical cost!Astronomical cost! Sea-Level Rise & Receding TargetsSea-Level Rise & Receding Targets Ecosystems are adapted to variable flows & salinity (not Delta as concrete canal)Ecosystems are adapted to variable flows & salinity (not Delta as concrete canal)

17. Abandoned Delta? Abandoned Delta? Peripheral Canal !Peripheral Canal ! (Voters rejected in 1982, but its back!) Ecosystem or sewer?Ecosystem or sewer? 560,000 acres of prime agriculture; $2B (in-Delta) agricultural economy560,000 acres of prime agriculture; $2B (in-Delta) agricultural economy

18. Restored Delta? Restored Delta? Restored to what?Restored to what? Sea level rise, invasive species & sediment supplySea level rise, invasive species & sediment supply Would this provide water supply reliability? Infrastructure corridors?Would this provide water supply reliability? Infrastructure corridors?

19. 3. Dual conveyance: Leaky peripheral canal & variable salinity Delta 4. Re-governance the Delta 5. STOP suburbanization! 6. Armored levees where needed (human life), abandoned levees for ecosystems & over- toppable levees for agriculture 7. Variable flow regimes & geomorphology 8. Carbon "farms"? 1.Coequal water supply & ecosystem goals 2. Dual conveyance facilities (instead of BAU or isolated Delta, both!) Governor’s Blue Ribbon Delta Visions Panel conclusions (2008):