Slide 1

UNDERSTANDING THE DELTA - AN ENGINEERING PERSPECTIVE Slide 2 Location of Delta and Relationship to CALFED Bay-Delta Program Solution Area Geographic Scope of Solution Geographic Scope of Problem Identification Sacramento Sacramento River San Joaquin River Stockton Suisun Marsh Slide 3 Major California Rivers Slide 4 Water Projects and Major Rivers in California Slide 5 Importance of the Delta Source of Drinking Water for 22 Million People 750 Plant & Animal Species Supports $27 billion Agricultural Industry Local Homes and Infrastructure 80% of the States Commercial Salmon Fisheries Californias Trillion Dollar Economy Slide 6 Sacramento San Joaquin Delta Outflow SWP and CVP Exports Vallejo, Solano CCWD - three intakes Slide 7 Contra Costa Water District Slide 8 Contributions to Delta Outflow (Annual Average = 28 Million Acre-Feet) Data Source: DWR Delta Atlas Slide 9 DELTA GOALS * Ensure good water quality for fish, for drinking water, agriculture and other beneficial uses Restore sustainable ecosystem and improve aquatic and terrestrial habitats Reduce mismatch between water supply and demand Improve structural integrity of Delta levee system and other facilities * Based on CALFED Bay-Delta Program Goals Slide 10 ENGINEERING APPROACHES FOR ACHIEVING GOALS Barriers/Tide Gates Water quality Fish Water levels Increased Flows San Joaquin River Recirculation Study Fish Screens and Fish Salvage New or Improved Conveyance Increased pumping capacity New or expanded storage Groundwater conjunctive use Off-stream or on-stream surface storage In-Delta storage Slide 11 Yellow diamonds represent dams in California Slide 12 SOFT PATH PROPOSALS FOR ACHIEVING GOALS Watershed Protection and Source Control Advanced Drinking Water Treatment Ultraviolet Disinfection Membranes Improved Water Use Efficiency Conservation Reclamation Water Transfers Removal of Barriers to Fish Migration Dam removal on smaller tributaries Wetland and Riparian Habitat Restoration Slide 13 Barriers/Tide Gates Delta Cross-Channel Gates Water Quality Fish South Delta Improvement Program Water Levels (for farmers) Fish (Head of Old River Barrier) Improved circulation for water quality Slide 14 Delta Cross Channel and Georgiana Slough DCC GeorgianaSlough SacramentoRiver SacramentoRiver Slide 15 Slide 16 Delta Cross-Channel Operated by U.S. Bureau of Reclamation Designed to increase flow of fresh Sacramento water into Central Delta (water quality) Closed at high flows to avoid Delta flooding May cause out-migrating salmon to stray Closed Nov-Jan (up to 45 days) and May-June (14 days) (fish) Oct-Nov 1999 closure for fish caused Delta water quality standards to be violated Slide 17 1999 Cross-Channel Closure Slide 18 CALFED Cross-Channel Experiments Goal is to protect fish as they move downstream without degrading Delta water quality What is effect of only closing gates only on ebb tide (when flow and fish moving downstream)? No impact on water quality Do fish move during day or at night? What is effect of only leaving gate open one flood tide per day (i.e., 6 hours)? Some impact on water quality Slide 19 CALFED South Delta Improvement Program Head of Old River barrier for fish Three operable barriers for agricultural water levels and quality Maintains water levels in channels for South Delta farmers (eastern side of barriers) Creates some circulation for water quality for farmers New fish screens for CVP and SWP export pumps Channel dredging Increased SWP export pumping Agricultural drainage reduction near CCWD intakes Slide 20 Slide 21 Rock Slough Intake (CCWD) Old River Intake (CCWD) Redirected Water Quality Impacts Poor Quality San Joaquin Inflow Slide 22 Proposals for Conveying Water Through or Around the Delta Peripheral Canal (1982) Through Delta - channel widening Chain of Lakes CALFED Modified Through-Delta Alternative Towing water bags Slide 23 Peripheral Canal Isolated conveyance around the Delta 29,000 cfs capacity Hood Export Pumps Slide 24 Sacramento River Through Delta Alternative Inundated Islands Setback Levees Slide 25 CALFED THROUGH-DELTA CONVEYANCE Slide 26 Central Delta Intake Concept ( ) Central Delta Intake Concept (not carried forward) Slide 27 New or Expanded Storage Proposals Los Vaqueros Expansion (add 400 TAF) Raise Shasta Dam (add 300 TAF) In-Delta Storage (250 TAF) Sites Reservoir near Willows (1.9 MAF) Expanded San Joaquin reservoir storage, e.g., Friant (add 250-700 TAF) Groundwater storage (500 TAF - 1 MAF) Slide 28 Los Vaqueros Reservoir Contra Costa Water District Slide 29 Slide 30 CCWD LOS VAQUEROS PROJECT 100,000 acre-feet off-stream reservoir for water quality and emergency water supply New 250 cfs screened diversion off Old River Blending water released from Los Vaqueros when needed to meet 65 mg/L delivered goal Provides ecosystem benefits because: CCWD takes water from reservoir during low flow periods (water quality) CCWD ceases diverting from Delta for 30 days in spring (fish protection) Slide 31 CCWD LOS VAQUEROS PROJECT 1987 -- Project planning and design begins Sept. 1994 -- Construction of reservoir began Summer 1997 -- First diversions from new intake Jan. 1998 -- Reservoir construction completed (first reservoir completed in California in 10 years) Jan. 1999 -- Reservoir full for first time July 1999 -- Los Vaqueros Project wins ASCE Outstanding Civil Engineering Achievement Award Slide 32 CALFED LOS VAQUEROS RESERVOIR EXPANSION STUDIES Identified in CALFED Record of Decision Would improve Bay-Area urban water quality and supply reliability Increase reservoir from 100 TAF up to 500 TAF. CCWD has contracted with DWR to perform studies of expansion. Closely coordinated with CALFED Bay Area Blending/Exchanges studies: Physical interconnections between agencies. Sharing of high quality water supplies to enhance delivered water quality for Bay Area users. Slide 33 SWRCB Estuarine Habitat Standards Adopted by State Water Board in 1994 Require 2 ppt salinity to be east of Roe Island, Chipps Island and Collinsville for a given number of days for the months of February through June Number of days at each location determined from runoff to Delta in previous month Number of days based on recreating flow conditions during 1968-1975 Number of days developed from historical flow data using CCWDs salinity-outflow model Slide 34 Los Vaqueros Reservoir Chipps Island Export Pumps Collinsville RoeIsland Slide 35 Salinity-Outflow Model Slide 36 Tidal Filling and Draining Slide 37 Storage of Water within Delta because of 14-Day Cycle of Mean Water Level Calculation of Suisun Bay Salinity based on Present and Previous Outflows from Delta Salinity-Outflow Model Net Delta Outflow Actual Delta Outflow Salinity at Chipps Island Slide 38 Salinity-Outflow Model Slide 39 For More Information CALFED Bay-Delta Program www.calfed.ca.gov Cal. Department of Water Resources www.dwr.water.ca.gov Contra Costa Water District www.ccwater.com Slide 40 Slide 41 CALFED PROGRAM AREAS Ecosystem Restoration Water Quality Governance Water Supply Reliability Watersheds Storage Conveyance Environmental Water Account Water Use Efficiency (conservation and recycling) Water Transfers Levees Science Slide 42 Montezuma Slough Control Structure Suisun Marsh Suisun Bay SUISUN MARSH SALINITY CONTROL GATES Sacramento River San Joaquin River Slide 43 Slide 44 ENGINEERING TOOLS Hydrologic and reservoir operation models Hydrodynamic transport models Contaminant transport models, e.g., salt transport Statistical correlations salinity-outflow fish-flow Conceptual fish population models Fish transport models Slide 45 How the system is run Northern California Hydrology: Wet year: 4 months with rain, 8 dry Dry year: 2 or 3 months with rain, 9 or 10 dry Critically dry: 3 or 4 storms in a year Major water sources: Sierra snowfall Basin rainfall Local rain and groundwater Slide 46 Tidal Influence Flows in Channels Tides up to 500,000 cubic feet per second Outflow typically 3,000 cfs to 100,000 cfs Tides and seawater intrusion Tides bring in seawater, river flows push it back Good water quality if outflow is 7,000 cfs or more Outflow is less than 5,000 cfs September through December