Transcript UNDERSTANDING THE DELTA - AN ENGINEERING PERSPECTIVE Richard A. Denton Water Resources Manager Contra Costa Water District.

UNDERSTANDING THE DELTA -
AN ENGINEERING PERSPECTIVE
Richard A. Denton
Water Resources Manager
Contra Costa Water District
Location of Delta and Relationship
to CALFED Bay-Delta Program
Solution Area
Sacramento
Sacramento
River
Suisun
Marsh
Geographic Scope
of Problem
Identification
San
Joaquin
River
Stockton
Geographic
Scope of Solution
Major
California
Rivers
Water Projects
and Major Rivers
in California
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 State’s Commercial
Salmon Fisheries
• California’s Trillion Dollar
Economy
Sacramento
Vallejo,
Solano
Delta Outflow
CCWD
- three
intakes
SWP and CVP
Exports
San Joaquin
Contra Costa Water District
Contributions to Delta Outflow
(Annual Average = 28 Million Acre-Feet)
Sacramento
Yolo
Eastside
Streams
San Joaquin
Precipitation
Data Source: DWR Delta Atlas
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
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
Yellow diamonds represent dams in California
“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
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
Georgiana
Slough
DCC
Sacramento
River
Delta Cross Channel
and Georgiana Slough
Sacramento
River
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
1999 Cross-Channel Closure
Salinity impact in Old River at Holland Tract due to DCC closure
from October 19 to November 9, 1999
350
Model - with Closure
Closed
Model - No Closure
300
Field Data
Chlorides (mg/L)
250
200
150
100
50
0
220
230
240
250
260
270
280
290
300
Julian Day 1999
310
320
330
340
350
360
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
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
Redirected Water Quality Impacts
Rock Slough
Intake (CCWD)
Old River Intake
(CCWD)
Poor
Quality
San
Joaquin
Inflow
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
Peripheral Canal
Isolated conveyance
around the Delta
Hood
29,000 cfs capacity
Export
Pumps
Sacramento River
Through
Delta Alternative
Inundated Islands
Setback Levees
CALFED THROUGH-DELTA CONVEYANCE
Central
Delta
Intake
Concept
(not carried
forward)
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)
Los Vaqueros Reservoir
Contra Costa Water District
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)
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
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.
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 CCWD’s salinity-outflow model
Roe
Island
Collinsville
Chipps Island
Los Vaqueros
Reservoir
Export Pumps
Salinity-Outflow Model
Chipps EC (mS/cm)
Chipps Island Daily Electrical Conductivity -- 1988
16
Field EC Data
14
Salinity-Outflow Model (straight Delta outflow)
12
10
8
6
4
2
0
88.0
Jan 88.1
Feb 88.2 Mar 88.2
Apr 88.3
1988
May 88.4 Jun
88.5
Jul 88.6
Tidal Filling and Draining
Antioch Tide
Hourly
4
Tidally-Filtered Stage
Tidal Stage (Feet)
3
2
1
0
-1
-2
1
3
5
7
9
11
13
15
17
19
March 2000
21
23
25
27
29
31
33
35
Salinity-Outflow Model
Salinity at
Chipps
Island
“Actual”
Delta
Outflow
Calculation of
Suisun Bay Salinity
based on Present and
Previous Outflows
from Delta
Net Delta
Outflow
Storage of
Water within
Delta because
of 14-Day
Cycle of Mean
Water Level
Salinity-Outflow Model
Chipps Island Daily Electrical Conductivity -- 1988
Field EC Data
16
Salinity-Outflow Model (straight Delta outflow)
Chipps EC (mS/cm)
14
Salinity-Outflow Model (tidal filling and draining)
12
10
8
6
4
2
0
88.0
Jan 88.1
Feb 88.2 Mar 88.2
Apr 88.3
1988
May 88.4 Jun
88.5
Jul 88.6
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
CALFED PROGRAM AREAS

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Ecosystem Restoration
Water Quality
Governance
Water Supply Reliability
Watersheds
Storage
Conveyance
Environmental Water Account
Water Use Efficiency (conservation and recycling)
Water Transfers
Levees
Science
SUISUN MARSH
SALINITY CONTROL GATES
Suisun
Marsh
Suisun
Bay
Sacramento
Montezuma
River
Slough
Control
Structure
San Joaquin
River
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
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
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