Comparing Futures for the Sacramento-San Joaquin Delta

Water exports from the southern Delta to users in the Bay Area and Southern California have become a central concern for the environmental health of the Delta, due to the dramatic decline of numerous fish species in recent years. This video discussion looks at two alternatives to those pumping operations, using the CALVIN model.

Lund discusses recent policy and technical discussions that have begun to revisit the idea of building a peripheral canal to divert water from the Sacramento River upstream of the Delta and deliver it to the export pumps. A canal or other form of upstream diversion of water exports involves a wide range of important decisions including: infrastructure, operations, environmental, governance, finance, etc.

This presentation by Wei-Hsiang Chen from the UC Davis John Muir Institute for the Environment explores the current and long-term effects of Delta export water quality on drinking water treatment cost and any public health risks from the disinfection process. Salinity, organic carbons, nutrients (nitrogen and phosphorous) and pesticides/herbicides are of primary interest.

Soil salinity has been a problem for agriculture in California's southern Central Valley for decades. Since the 1950s, the Delta has been a major source of surface water for the region, but salinity is once again becoming a major issue. Howitt provides preliminary estimates for long-term revenue losses for irrigated crops and confined animal operations in the Southern Central Valley as a result of salt accumulation.

What is the best decision for managing water exports in the Delta? Jay Lund asks. This presentation looks at four strategies and how they may affect environmental sustainability and reliable water supply by mid-century to account for natural forces acting in the Delta, such as sea level rise.

Ellen Hanak, of the Public Policy Institute of California, reviews several governance and regulatory challenges for the management of the Sacramento-San Joaquin Delta. She takes into account the changes occurring in this region as a result of sea level rise, increasing risk to levees, inevitable changes in the sustainability of beneficial uses due to sea level rise and additional permanent island flooding, and the challenges posed by declining populations of native fish species.

Robyn Suddeth, a graduate student in the UC Davis Center for Watershed Sciences, outlines the major factors that make levees in the Sacramento-San Joaquin Delta landscape susceptible to future flooding — sea level rise, seismicity, subsidence and changing inflows. She then discusses the economic methods for approaching the evaluation of Delta island levee upgrades and repairs.

Peter Moyle and William Bennett, UC Davis Center for Watershed Sciences, address four basic questions about fish in their role as major drivers of ecosystem-related policy in the Delta: 1) what species are important for making decisions that affect ecosystem function? 2) what are likely attributes of a future Delta ecosystem? 3) what are likely effects on fish of the four strategic water export alternatives? and 4) what actions could improve the Delta for desirable fish species?

This presentation provides a report on the collective views of 39 experts on Delta fish and ecology regarding the likely responses of key species to different modes of water management in the Delta. The four key species include delta smelt, longfin smelt, young striped bass and juvenile Sacramento River Chinook salmon.

William Fleenor, UC Davis Center for Watershed Sciences, presents an initial assessment of the salinity implications of four strategies for managing delta water exports. He also explores the impacts on salinity due to two main changes to the Delta over the past century: One to three feet of sea level rise and increased island flooding.