Constraints in the Sacramento-San Joaquin Delta
Paul A. Marshall, Chief Bay Delta Office March 19, 2015
Adapted from Jaime Anderson, PhD, PE Bay Delta Office Bay-Delta System
DSM2 Domain Sacramento Sacramento River
Redding
Stockton San San Joaquin Francisco River San Francisco
47% of California’s runoff Los Angeles passes through the Delta
San Diego 2 Bay-Delta detail image from CALFED Natural State • Series of dendritic “branching” channels • Seasonal wetland – Winter flooded fresh water – Summer shallow channels saline water • Native species adapted to seasonal salinity, flow, and temperature changes
3 1850’s Levee Construction
Physical modifications (dredging, levees, pumps, gates, resevoirs, etc) 4 Modern Delta Highly managed – Reservoirs – Gates & barriers – Pumps – Levees
5 Human Influences
Commercial shipping: Sacramento and San- Joaquin Deepwater Ship Channels
Recreation: fishing, hunting, boating, passive enjoyment 6 Subsidence
7 Land Subsidence: a historical fact Pre-1880’s
Present Time
Levee Failure
8 Land Subsidence Due to Farming & Peat Soil Oxidation - 25 ft.
- 20 ft.
- 15 ft.
Below Sea Level - 5 ft. -30 -20 -10 -5 ft 9 Physical Processes
• Hydrodynamics
– Hydraulics: flood flows, tidal action
– Sedimentation
– Erosion
10 Seismic Risk
Bay Delta Region Major Faults 11
Levees have risk of failure during a seismic event
• Levees remain susceptible to earthquakes even after PL84-99 improvements are made
12 Agricultural Diversions
• Since the 1850’s • Economy • Water Quality
13 1930’s Propaganda for CVP
14 Salinity Intrusion Before and After Managed Upstream Reservoirs
Before After (1920 –1943) (1944 –1990)
15 16 Delta Inflow Refresher
Sacramento River ~80% Inflow; good quality East Side Rivers ~5% Inflow; good quality Ocean/Tidal High salinity
San Joaquin River
~15% Inflow; poor quality 17 Flow of Water for State and Federal Projects 1 Sac River – Delta Cross Channel 3 – Mokelumne River Sac River / – Old & Middle Rivers West Delta 2 San Joaquin River
SWP Pumps
CVP Pumps 18 Delta Cross Channel
Sacramento River
DCC Gates
Delta Cross Channel
19 Skinner FF Clifton Court Forebay
CCF Intake Banks PP
Tracy PP
Tracy Fish Collection Facility
20 Contra Costa Water District Rock Slough • 550,000 customers Intake • Contra Costa Canal – Rock Slough Intake (350 cfs) • Los Vaqueros Reservoir Old R. Intake – Old River Intake (250 cfs) – 100,000 ac-ft storage – Completed 1997
Los Vaqueros Reservoir
21 Delta Water Use
Sacramento
Ocean In-Delta Stockton 76% 6%
18% Bay Area Central Valley & Southern Cal 22 South Delta Temporary Barriers
Grant Line Canal Middle River Head of Old River
Stockton Jones Roberts ● Tract Island Clifton Court Union Island Forebay Fabian Tract Old River at Tracy 23 Sutter Flood Control Bypass and Fish
• Sutter Bypass – Tisdale Weir • Yolo Bypass Yolo – 59,000 acres Bypass – Fremont Weir 33.5 ft crest elev. – Vic Fazio Yolo Wildlife Area
24 Winter Run Chinook Salmon
120,000
100,000
80,000
60,000 1989 listed as CA endangered species 40,000
20,000 Passing Red Bluff Diversion Dam Bluff Diversion Red Passing Number of Adult Chinook Salmon Salmon Chinook of Adult Number 0 1965 1970 1975 1980 1985 1990 1995 2000 Year
25 Habitat (water, food, spawning)
• Fish listed under Endangered Species Act – Chinook Salmon ─Delta Smelt
• Protecting listed fish – Take limits at SWP pumps – Reverse Flow controls – Biological opinions restrict other DWR activities
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