Making the Most of our Surface Storage – a San Diego Story

San Diego County Water AuthorityAmy Chen

MWD Program Chiefachen@sdcwa.org

Overview of PresentationSystem OverviewReservoir SystemsRegional Investments in Supply ReliabilityHistorical Use and Operations of

ReservoirsConclusions

2

3

The Water Authority formed in 1944 under County Water Authority Act 24 member agencies 36-member Board of Directors

Service Area Approximately 3.1 million residents

(97% of County population) Regional economy of $186 billion

Facilities 300 miles of large diameter, gravity

flow pipeline in two major alignments

131 service connections - treated and untreated

Dams, reservoirs, pump stations, hydroelectric facilities, treatment plant

San Diego County Water Authority

Water Authority Service Area Historic and Projected Normal Year Demands

450

500

550

600

650

700

750

800

850

1990

1993

1996

1999

2002

2005

2008

2015

2018

2021

2024

2027

2030

2033

Tota

Dem

and

(TA

F)

2010 UWMP Projected Demand(after SBX7-7 retail compliance)

1990-2010 Historic Demand

4

San Diego Region WatershedsSan Juan

Santa Margarita

Orange County

San Diego County

Impe

rial C

ount

y

San Luis Rey

CarlsbadSan Dieguito

Penasquitos San Diego River

SweetwaterPueblo

OtayTijuana

5

San Diego County Reservoir Storage Overview

Reflects historic and modern investments25 Reservoirs in the San Diego Region

Total Storage Capacity 590,000 AF12 Supply reservoirs connected to aqueduct

systemCurrent Regional Storage level is: 395,000 AF

Water Authority Storage is : 47,000 AFReservoirs are owned and managed by Member

Agencies (Except Olivenhain)

6

Storage Pools by Reservoir

Barre

tt

Dixon

Hen

shaw

Jenn

ings

Lower

Ota

y

Mor

ena

Oliv

enha

in

Ramon

a

San

Diegu

ito

Suth

erla

nd

Woh

lford

0%10%20%30%40%50%60%70%80%90%

100%

Member Agency Emergency Water Authority 7

Henshaw

Dixon

WohlfordEscondido-Vista WTP

Total Storage = 61,000 AFTreatment = 65 mgd

Sutherland

San Vicente*

El Capitan

Miramar WTP Miramar

MurrayAlvaradoWTP

Total Storage = 243,000* AFTreatment = 415 mgd

Olivenhain

HodgesOlivenhain WTP

Total Storage = 58,000 AFTreatment = 34 mgd

El CapitanJenningsLevy

WTP

Cuyamaca

Total Storage = 28,000 AFTreatment = 106 mgd

Loveland

SweetwaterPerdueWTP

Total Storage = 53,000 AFTreatment = 30 mgd

Barrett

OtayOtayWTP

Morena

Total Storage = 138,000 AFTreatment = 40 mgd

8

$2.5 billion regionally since 2000$1.5 billion Emergency/Carryover

Storage ProjectNew and expanded surface storageReoperation of existing reservoirs

$800 million in treatment to optimize conjunctive use of storageTwo new treatment plantsExpansion of three existing plants

Regional Investments In Storage Operations and Conjunctive Use Since 2000

9

ESP/CSP

10

200,000 AF of regional storageOne new reservoir and

Dam (Olivenhain)Raise of existing San

Vicente DamConnect Lake Hodges

to existing AqueductPipelines and Pump

stations to optimize treatment and conveyance

Final Phase in Construction

San Vicente Dam Raise complete late 2012

Project: Olivenhain Dam & ReservoirComplete: 2003Cost: $198 millionBenefit: 25,000 AF of storage

11

Project: Lake Hodges ProjectsComplete: 2011Cost: $196 millionBenefits: 20,000 AF ESP storage; 40MW power

12

Project: San Vicente Pipeline & TunnelComplete: 2011Cost: $459 millionBenefit: Improved Water Delivery

13

Project: San Vicente Dam RaiseComplete: 2012Cost: $482 millionBenefit: 152,000 AF of new storage

14

15 15

16 16

Complete: 2008Cost: $179 millionBenefit: 100 MGD treated supply for region 17

Project: Twin Oaks Water Treatment Plant

San Diego Regional Investmentsin Treatment

Project Cost

Levy Water Treatment Plant Expansion $46,000,000

Olivenhain Water Treatment Plant $98,000,000

Alvarado Water Treatment Plant Expansion $202,000,000

Earl Thomas Reservoir upgrade $31,000,000

Miramar Water Treatment Plant Expansion $200,000,000

Otay Water Treatment Plant Expansion $25,000,000

Otay Water Treatment Plant clear well $10,000,000

Twin Oaks Valley Water Treatment Plant $179,000,000

Total $791,000,000

18

Multi-purpose ReservoirsCapture local runoffAnnual yield

Average 59,600 AFSeasonal shift of raw water demand from

summer to winter to reduce summer peak demand

Managing variations in weather and runoffFlood control considerationsRegulatory storage to feed water treatment

plants19

10 Year Reservoir Imported/Local

1999 2000 2001 2002 2003 2004 2005 2006 2007 20080

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

SSOA/SSS Take Local Production

20

Actual Example of Using Reservoirs to Shift Peak Demands

Jan-

07

Jan-

07

Feb-0

7

Mar

-07

Mar

-07

Apr-0

7

May

-07

May

-07

Jun-

07

Jun-

07

Jul-0

7

Aug-0

7

Aug-0

7

Sep-

07

Oct-0

7

Oct-0

7

Nov

-07

Dec-0

7

Dec-0

7100

300

500

700

900

1100

1300

1500

Actual Adjusted for w/o SSOA Deliveries

cfs

21

ConclusionsDue to geologic constraints, limited groundwater

basins in San Diego countySurface reservoirs were built to capture runoff

Majority of reservoirs were built before imported water Designed to maximize yield from local runoff

Since imported water deliveries, Water Authority has worked with member agencies to optimize use of imported water Integration of regional system with member agencies

systems Additional reservoirs; conveyance system; treatment plants

Coordinated efforts continue today to ensure supply reliability and facility optimization

22