08/21/2019
Water Storage and Conveyance 101
Zone 7 Board Meeting August 21, 2019
Amparo Flores, P.E., Ph.D. Zone 7 Water Agency
Outline
1. Tri-Valley’s Water Supplies 2. The State Water Project System 3. Conveyance of Imported Water 4. Zone 7’s Storage System
Slide 2
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Tri-Valley Water Supplies
. Most of the region’s water supply served by Zone 7 and the retailers Sources of Supplies is imported, not local Provided by Zone 7
. Currently, about 70% of the supply 9% comes from the State Water Project (SWP) via the Delta 11%
. Recycled water for irrigation 10% supplies about 10%
. Zone 7 stores excess imported 70% surface water in the local groundwater basin, remote
groundwater banks in Kern State Water Project (Zone 7) County, and in San Luis Reservoir Arroyo Valle (Zone 7) Groundwater Quotas (Retailers) . Zone 7 provides about 80% of the Recycled Water (DSRSD/Livermore) supplies served to the region
Slide 3
State Water Project (SWP) System
• SWP System • Delivers the year’s “Table A” allocation • Other SWP water Oroville • Other water, when capacity is Reservoir available
San Luis • 29 SWP Contractors: Delta Reservoir • 23 Mostly Urban Conveyance • 6 Mostly Agricultural System • Water Supply Contracts
California • 4,200,000 AF in Table A Aqueduct amounts • Zone 7: 2% of the SWP Groundwater Banks (Semitropic and Cawelo)
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ConveyanceQUESTIONS? of Imported Water
Conveyance of Imported Water
Slide 6
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Conveyance of Imported Water
The California Aqueduct conveys water to SWP contractors in central and southern California. It also conveys excess Zone 7 water to Kern County to “bank” for future use.
Slide 7
ExistingConveyance Conveyance of ImportedSystem Water
. South Bay Aqueduct (SBA) conveys: . water to treatment plants, . water to agricultural customers, and . releases to the arroyos.
Z7 Transmission System PPWTP Chain of Lakes . The South Bay Aqueduct (SBA) is the only way imported water . Currently, conveyance to Zone supplies are delivered to Zone 7’s 7 is limited to SBA. system to serve the Tri-Valley. . Capital Improvement Program . The SBA is also used to deliver local water captured in Lake Del Valle. includes new conveyance DVWTP projects. . The California Aqueduct conveys excess Zone 7 water to Kern County to “bank” for future use. Slide 8
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QUESTIONS? Zone 7’s Storage System
Lake Oroville Existing Storage System
Sacramento
Local Groundwater Chain of Lakes: Basin (Main Basin) • Lake I • Cope Lake San Francisco
South Bay Aqueduct Lake Del Valle San Jose
San Luis Reservoir
Fresno
Cawelo Water District Semitropic Water Storage District
Bakersfield Slide 10
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Zone 7’s Storage System Above-ground: surface water reservoirs
OWNED BY DWR: OWNED BY ZONE 7: San Luis Reservoir Lake Del Valle Lake I Cope Lake
Storage Zone 7’s Operational Current Storage Storage Amount (acre-feet) (acre-feet) San Luis Reservoir 10,000-15,000 10,000
Lake Del Valle 7,500 8,500
Lake I 10,800 (26,800 total) 20,500
Cope Lake 4,500 4,400
Slide 11
How do the reservoirs get filled?
Above-ground: surface water reservoirs
San Luis Reservoir: Lake I: • water pumped from • Fills with groundwater the Delta, into the and rainwater California Aqueduct, • Mine water recaptured and diverted to San in Cope Lake then Luis Reservoir conveyed to Lake I • water stored via paper exchange
Lake Del Valle: • Arroyo Valle flows Cope Lake: directly into Lake Del • Vulcan mine water Valley, collecting water pumped into Cope from upstream Lake watershed • Fills with rainwater • DWR pumps Delta water into the lake
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Zone 7’s Storage System Below-ground: groundwater aquifers Managed by Zone 7: Local groundwater basin (“Main Basin”)
Storage Agreements: Kern County Groundwater placeholder Banks Semitropic Cawelo Below-ground: groundwater aquifers MANAGED BY ZONE 7: KERN COUNTY GROUNDWATER BANKS: Livermore Valley Groundwater Basin Semitropic Water Storage DistrictSlide 13 Cawelo Water District
Storage Zone 7’s Operational Storage Current Storage Amounts Capacity (acre-feet) (acre-feet) 126,000 Livermore Valley Groundwater Basin (+128,000 of emergency 251,000 (“Main Basin”) storage) Kern County Groundwater Banks:
Semitropic Water Storage District 78,000 86,000
Cawelo Water District 120,000 26,400 Slide 13
How does the Main Basin get filled?
Rainfall Recharge
Lake Recharge
Applied Stream Groundwater Mining Losses Evapo- Water Recharge Pumping transpiration Recharge
Groundwater Groundwater Inflow Water fills the spaces Overflow between the sand, gravel, etc. Slide 14
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Groundwater Banks What is the purpose of groundwater banking?
. Groundwater banking is part of normal operations, providing a buffer against variable supply conditions. . The amount of water provided by the SWP each year currently averages 50% . . In years when we have extra water (usually wetter conditions), we bank the extra water. . In years when we do not have enough incoming supplies (drier conditions), we withdraw water from the banks.
Slide 15
Groundwater Banks How do the banks get filled?
Zone 7’s surface water is conveyed via the California Aqueduct south to Kern County…
. “In-lieu exchange”: farmers then use our surface water and leave groundwater in the aquifer to add to our bank account, and/or . Surface recharge: surface water is placed in spreading ponds or recharge basins, goes into the aquifer, and is deposited to our account Credit: Kern County Water Agency Slide 16
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Groundwater Banks How do we withdraw our water Example of a from the banks? water exchange . We do not pump water from south to MWD’s water north. pumped from the Delta and delivered . Water withdrawal to Zone 7 from banking Zone 7’s programs is done groundwater in Kern through “exchanges”. County pumped into the CA Aqueduct
. A similar approach is MWD receives water used for San Luis from the California Aqueduct, inc. Reservoir pumped . We intercept water in groundwater. the Delta then DWR reduces our balance of water in San Luis Reservoir. Slide 17
Kern County Groundwater Banks
Kern County Deposits 140,000 kern County Withdrawals Total Kern County Storage 120,000
100,000
80,000
60,000
40,000
20,000
Acre-Feet of Water 0
-20,000
-40,000 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
Slide 18
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Chain of Lakes
Owned by Zone 7
Complete Chain of Lakes by ~2060: + 120,000 AF total storage +16,000 AF operational storage Slide 19
QUESTIONS?
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