Transcript Slide 1
Achieving California’s Water Supply and Delta Ecological Improvement Simultaneously Stacy K. Li, PhD Aquatic Systems Research My experience working in the Delta Broader perspective was needed Ca 1956 in the San Joaquin Delta Thank you - The Late Don W. Kelley and John R. Gildersleeve It’s Time to Decide The Delta water export system is broken: Do we continue to refurbish and update the present system? Or do we design a new system? In either case - There will only be one chance because of the immense expense and time pressures (avoid levee failure, permitting and construction). REMINDER: Delta Restoration Goals Secure Water Supply Restore the Delta Ecology What is at Stake? California is the fifth largest economy in the world with $1.5 trillion annual gross state product (as of 2008). The world economy is affected by the economy of California. The economy of California depends upon water. Therefore, you are affected even if your water supply is not the Central Valley Project or the State Water Project. Some Reasons for Urgency Levee and water diversion failures imminent in the Delta Inconsistent design, construction, and maintenance of levees Levees not as reliable or as safe as dams. Island subsidence Proximity to major earthquake faults - 6.5 Richter Levees expensive ($8,000 lineal foot X 5280 feet/mile X 1,100 miles) Lower Jones Tract failure occurred on a sunny day. Climate Change Increase range of tidal flux (levee concern) Increase in storm surge (levee concern) Loss of Sierra snow pack (4 million acre feet) San Joaquin flow reversals - over 300 days annually Fish population collapses - Several species at all-time lows Declining water quality -Ag return flow, stockyards, dairy operations Salt importation into San Joaquin Valley increasing - 1 million tons/year Human population increasing - about 1 million/year (50 M 2026?) Outflow to SF Bay 1/2 of historical Water supply nearing capacity limits - (>88.7%) SAC SJR outflow export MIX Water supply expor Central Valley Project (USBR website) San Joaquin River used as water supply (Friant Dam, Madera Canal, Friant-Kern Canal) Sacramento River used to resist seawater intrusion into the Delta (Shasta and Folsom dams) and to freshen San Joaquin water (Delta Cross Channel). Send mitigation water to San Joaquin River senior water rights holders (Jones pumping plant, Delta Mendota Canal). Provide freshwater diversion site for Pittsburg and Antioch to mitigate for salt intrusion (Rock Slough Intake, Contra Costa Canal). CVP NEVER implemented use of Sacramento River water as water supply (peripheral canal!). [SWP uses Feather River (Oroville Dam) and relies upon through Delta water conveyance (Banks pumping plant, California Aqueduct).] WATER SUPPLY Typical Delta Hydrological Budget Delta Atlas 1995 (1980-1991) Other 4% Losses Water supply exports San Joaquin System 6% 18% 20% Flow to the Bay Sacramento System 76% 76% OUTPUT INPUT 27840 TAF The Key Concept: WATER BEHAVES DIFFERENTLY: They typically do not mix Sacramento River: Higher gradient (0.026). Higher momentum. Higher hydraulic energy. Higher inertia. Higher current. Lower suspended solids concentrations. San Joaquin River: Lower gradient (0.016). Lower momentum. Lower hydraulic energy. Lower inertia. Higher residence time. Higher salinity. THEY DO NOT IMMEDIATELY MIX! Van Sickle Island Sacramento River Three Mile Slough Sherman Island San Joaquin River Aerial photograph showing lack of mixing at the confluence of the Sacramento and San Joaquin rivers. The Key Consequences Sacramento River water is largely unavailable to either CVP (Jones PP) or SWP (Banks PP). Through Delta Water Conveyance is infeasible. Water available is not 27,840 TAF (Delta inflow), but closer to 5,660 TAF (SJR inflow). f No Good Alternate Sacramento River Water Sources Georgiana Slough? - Inlet controlled Delta Cross Channel? - Outlet controlled Three Mile Slough? - to Sacramento R. Pump harder, longer? - Suisun Bay water is brackish! Ecological Canaries SPECIES Delta smelt (T) Longfin smelt (ST) Striped bass YOY Threadfin shad Chinook salmon (SC) Steelhead (T) CRITICAL FACTOR Backwater habitat Backwater habitat Feeds on plankton Feeds on plankton Ocean? Home? Ocean? Home? 80 60 40 20 0 Merced R. Tuolumne R. Stanislaus R. Cosumnes R. Mokelumne R. American R. Yuba R. SAN JOAQUIN WATERSHED EASTSIDE STREAM SACRAMENTO WATERSHED Feather R. Butte Ck. Deer Ck. Mill Ck. Battle Ck. Cottonwood Ck. -80 Clear Ck. 100 Cow Ck -20 U. Sac Stem -40 109 328 245 341 102 Percent of 1967-1991 Production Baseline AFRP 1992-2006 : Fall-run Chinook Salmon -60 Improve Delta Ecology: Mimic Historical Conditions Restore backwater habitat No SJR export - no current! Enhance plankton communities No SJR export - higher residence time! Provide smolt emigration cues No SJR export - A downstream! Provide adult attraction No SJR export - an flows upstream! New Delta Design Rules Use Sacramento River as water supply (21.2 MAF vs 5.66 MAF). 15.54 MAF remains for water quality and outflow. No water export of San Joaquin water. Use San Joaquin water to assist in resisting salt intrusion into Delta. Keep outflow to SF Bay at current levels or higher. It is presently at 50%! Peripheral Canal Water supply secured. Flow reversal on Sacramento River unlikely. San Joaquin Delta ecology improved. Great improvement of POD species and anadromous species in San Joaquin Delta Water system not as susceptible to levee failure. Salt importation to San Joaquin Valley much reduced. Reduced water processing costs. Education of general public needed.