Delta Water Conveyance — Water Project Operations and Risks Mark A. Holderman, PE Bay Delta Office 1

Basic Water Dilemma: Rainfall Distribution Part of DWR’s mission is to operate the State Water Project. So one of our jobs is to move water from where it’s plentiful to where its needed, which includes the more arid parts of the State where most of the agriculture takes place and most of the people live and work.

Central Valley and Delta are Intensively Managed Water Systems ■ Major Rivers ■ State Projects ■ Federal Projects ■ Local Projects The State has been re-plumbed over the past century to do move the water around. Many projects have been built and operated by not only the State and federal governments, but also local water districts and cities. SWP’s Oroville Reservoir California Aqueduct CVP’s Shasta Reservoir Delta-Mendota Canal

You are here! Delta confluence of Sacramento River, San Joaquin River, and various Eastside streams—all converging and flowing into the San Francisco Bay to the ocean

Ocean/Tidal High salinity Delta Inflow Sacramento River ~80% Inflow; good quality East Side Rivers ~5% Inflow; good quality Ocean/Tidal High salinity Sacramento River main flow contributor w/ good WQ San Joaquin flows south to north and contains poorer WQ due to agricultural drainage from central valley farming activities Eastside streams flow from the Sierra foothills with good WQ Ocean tides twice daily with huge tidal flux flows and containing ocean derived salts San Joaquin River ~15% Inflow; poorer quality

How Water Gets to State and Federal Pumps Sac River – Delta Cross Channel – Mokelumne River – Old & Middle Rivers 1 Sac River / West Delta 3 San Joaquin River 2 Sacramento River conveys water from natural winter and spring runoff as well as SWP/CVP upstream reservoirs (Oroville and Shasta, Folsom) through the DCC (if open) and down Mokelumne River. Once into the central Delta, the water travels upstream on Old and Middle River to CCF and Banks PP/Jones PP. SJR conveys water from runoff and CVP reservoir releases into the Delta where water can travel down Old River at the head of Old River directly to the CVP/SWP, or a more roundabout route via Middle River/Victoria Canal or even further downstream via and Turner and Columbia Cuts (reverse flows). When DCC isn’t open, Sacramento River water travels around Sherman Island and enters Old River from the West Delta. Increased salinity occurs when the water takes that route. SWP Pumps CVP Pumps

SWP and CVP Delta Export Facilities SWP Skinner FF SWP Clifton Court Forebay CCF Intake SWP Banks PP CVP Jones PP CVP Tracy Fish Facility

Delta Control Structures N Montezuma Sl. Salinity Control Gates Delta Cross Channel Middle R. Barrier Grant Line Canal Barrier Head of Old R. Fish Barrier Old R. Tracy Barrier Montezuma Sl. Salinity Control Gates Clifton Court Forebay Gates Delta Control Structures

USGS Flow Monitoring Network

D-1641 Bay-Delta Standards Stations

Requirements for Fish Protection Delta flow requirements met by controlling SWP & CVP exports Shallow water habitat development Operational actions for existing facilities Fish studies

Fish Guidance Devices (Bio-acoustic Fish Barriers) Georgiana Slough Head of Old River

Threats to Delta Stability Subsidence Random levee failure Floods & other causes Earthquakes Climate change Sea level rise, flood intensity

Subsidence: Compaction, wind erosion, burning and oxidation of peat soils

Land Subsidence - 30 ft. - 20 ft. - 5 ft. Subsidence ~ 1.5 ft. per decade 30 ft. in some areas - 30 feet Sea Level 16

Earthquakes Erosion Overtopping Burrowing Animals Seepage/Stability Stability

It can get rough out there! WHY ARE LEVEES IMPORTANT? FLOOD PROTECTION!

USGS report in 2003 estimates a 62% or greater between 2003-2032 in the SF Bay area.  several breaches in Delta levees. Faults = Hayward, Calaveras and San Andreas pose greatest threat to Delta.

Levees have risk of failure during a seismic event

Three Breach Scenario before breach event Simulated salinity, ppt Andrus Andrus Sherman Sherman Bacon Bacon Simulated salinity, ppt with Delta pumping Simulated salinity, ppt without Delta pumping

31 days after breach event Three Breach Scenario 31 days after breach event Andrus Andrus Sherman Sherman Bacon Bacon Simulated salinity, ppt with Delta pumping Simulated salinity, ppt without Delta pumping

You’re going here!

Department of Water Resources Mark A. Holderman, PE Department of Water Resources Bay-Delta Office Mark.Holderman@water.ca.gov

2 days after breach event Three Breach Scenario 2 days after breach event Andrus Andrus Sherman Sherman Bacon Bacon Simulated salinity, ppt with Delta pumping Without Delta pumping With Continued Exports Without Continued Exports

14 days after breach event Three Breach Scenario 14 days after breach event Andrus Andrus Sherman Sherman Bacon Bacon Simulated salinity, ppt with Delta pumping Without Delta pumping With Continued Exports Without Continued Exports