Keywords:land use, water supply
Despite heavy rains in March 1991, California continues to face a serious near-term water problem resulting from five years of drought. In fact,...
Despite heavy rains in March 1991, California continues to face a serious near-term water problem resulting from five years of drought. In fact, the amount of water in storage on October 1, 1991 was about equal to the amount in storage one year ago—a year in which strict conservation measures were imposed in some areas and there were significant reductions in water supplies for many agricultural users. In this paper, we provide background information on California's water system, the impact of the drought, water needs in the future, and legislative options for coping with water supply limitations.
The purpose of this Policy is to increase the use of recycled water from municipal wastewater sources that meets the definition in Water...
The purpose of this Policy is to increase the use of recycled water from municipal wastewater sources that meets the definition in Water Code section 13050(n), in a manner that implements state and federal water quality laws. The State Water Board expects to develop additional policies to encourage the use of stormwater, encourage water conservation, encourage the conjunctive use of surface and groundwater, and improve the use of local water supplies.
When used in compliance with this Policy, Title 22 and all applicable state and federal water quality laws, the State Water Board finds that recycled water is safe for approved uses, and strongly supports recycled water as a safe alternative to potable water for such approved uses.
Water year 2015 added a fourth year to the ongoing drought in California, with observations indicative of a changing climate, including record warmth....
Water year 2015 added a fourth year to the ongoing drought in California, with observations indicative of a changing climate, including record warmth. The Water year ended with record high temperatures, and preceded a period of historically low precipitation that started in 2012. April snowpack measurements in 2014 tied the historic record low of 1977.
Expectations of a developing El Niño event in the eastern tropical Pacific fueled notions that water year 2015 would be better. However, during the first two months of the water year, warm temperatures persisted and precipitation continued to fall short of expectations. The developing El Niño event stalled as California headed into the heart of its wet season.
In 2014, the snowpack level was 25% of its average on April 1. That mark was shattered on April 1, 2015 when snowpack amounted to a meager 5% of average. Satellite-imagery compares the Sierra Nevada snowpack near the end of March 2015 to the average conditions in water year 2011. This extreme low in snowpack exceeds end-of-century climate projections.
When accompanied by the record warm temperatures experienced in the 2015 water year, there is conversation of California having shifted to a new climate “normal”.
In this report Environmental Defense provides a planning-level analysis for replacing the water and hydropower benefits that the Hetch Hetchy Reservoir and O’Shaughnessy...
In this report Environmental Defense provides a planning-level analysis for replacing the water and hydropower benefits that the Hetch Hetchy Reservoir and O’Shaughnessy Dam provide.We show how practical, proven water storage, conveyance and treatment alternatives can provide San Francisco a healthy, reliable and secure supply of water that is adequate for current and future needs. We also explain how hydropower lost as a result of restoring the valley can be replaced without contributing to air pollution or global warming. The alternatives analyzed do not comprise all possible options, but they do demonstrate that workable solutions for restoring Hetch Hetchy Valley exist.
We began this study with the premise that all solutions must be technologically feasible and affordable and must assure a dependable supply of safe drinking water. In addition to addressing the water and power needs of San Francisco and other Bay Area communities that rely on the Tuolumne River, solutions must also protect all affected California communities. Most obviously, any restoration plan must protect the Turlock and Modesto Irrigation Districts, whose uses of the Tuolumne River predate and are intertwined with those of the San Francisco Public Utilities Commission (SFPUC) and its customers. Of course, a restoration plan must also consider the Groveland area, both as a user of the Tuolumne River water and as a gateway community to the Hetch Hetchy region of Yosemite National Park.
Our analysis focuses mainly on alternative ways to move and store San Francisco’s existing supply of Tuolumne River water. Environmental Defense developed the TREWSSIM (Tuolumne River Equivalent Water Supply Simulation) model to evaluate the SFPUC’s system performance under a range of water supply alternatives, with and without Hetch Hetchy Reservoir.TREWSSIM incorporates features of both the SFPUC’s planning model HHSM-LSM and the state-federal CALSIM model. The TREWSSIM analysis addresses not only water supply issues, but also water treatment and hydropower.
Three expert consultants assisted in our analysis: Schlumberger Water Services provided engineering analyses and modeling assistance; Eisenberg, Olivieri and Associates analyzed water quality issues; and Somach, Simmons & Dunn assessed the legal landscape.
Academic experts provided peer review. The San Francisco Public Utilities Commission, the Bay Area Water Supply and Conservation Agency, and the Turlock and Modesto Irrigation Districts also provided information to help ensure an accurate report.