Day

April 13, 2022
subisdence on 4 delta islands map

Asked to suggest an appropriate future for four Delta islands owned by the Metropolitan Water District, it’s difficult not to want the moon.

Why not richer rice fields, more wetlands, better boat launches, extended trails, even eco-tourism? ? A new survey for the Delta Islands Adaptation Project, funded by a Prop 1 Watershed Restoration Grant, wants the public’s opinion on the importance of 10 possible land-use objectives leading to the selection of one of the four islands for improvements. As your blinking cursor hovers over a satellite image of Bouldin, Bacon, Webb, and Holland Tracts, the survey lays out all that the experts...
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chart by Hutton

An examination of 50 years of records reveals an apparent seasonal bias in estimates of freshwater flow from the Delta to the San Francisco Estuary.

The seasonal bias suggests flows were overestimated during the summer months and underestimated during the winter. Estimates of Delta outflow use a measurement called net Delta outflow index (NDOI), which is determined by taking the amount of Delta inflow, from sources such as the Calaveras, Sacramento, and San Joaquin rivers, and subtracting Delta exports, a direct measurement, and net Delta channel depletions. A team led by TetraTech’s Paul Hutton compared NDOI estimates against measured Delta outflow at four points, as...
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diagram of fish net trawl

Fish monitoring surveys in the San Francisco Estuary net different numbers of different fish species depending upon when and how they sample.

According to a new study published in San Francisco Estuary and Watershed Science, even surveys that target the same part of the water column can come up with significantly different catches. The study’s authors analyzed decades worth of data from the California Department of Fish and Wildlife (CDFW) Fall Midwater Trawl, which spans from San Pablo Bay to the upper Delta; CDFW’s San Francisco Bay Study midwater and otter trawls, covering the South Bay to the central Delta; and the...
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field in delta with irrigation

Rain or shine, farmers in California use about the same amount of water every year, while residential water use varies considerably with precipitation.

A research team led by UC San Diego’s John Helly processed 15 years’ worth of water-use data from the state’s Department of Water Resources, reporting in the March 2022 issue of San Francisco Estuary and Watershed Science that while “the annually precipitated water supply in the Bay-Delta” varied by 30%, agricultural water use scarcely changed year to year. “The water management system maintained nearly constant agricultural water use even in periods of intense drought, with year-to-year variation of about 7%,”...
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Science in Short: Daylighting Delta Data

Once you know how many fish are present in a particular part of a river, including additional details like the time of day and water temperature, what do you do with this information? For decades, Delta researchers have collected millions of similar data points from daily visits to the San Francisco Estuary, not all of which are available or immediately useful. How that information is then translated into a language relevant to water and conservation managers requires serious number, or...
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Atmospheric Rivers Intensifying as World Warms: How the West Will Know What’s Coming

In just a few years, tracking the West Coast’s atmospheric rivers by airplane has gone from what one hydrologist called “really wild-eyed stuff” to a Congressionally-funded operation. This Atmospheric River Reconnaissance program, which wrapped up its latest season in March, monitors these increasingly powerful storms as they shoot across the Pacific Ocean and delivers real-time data to National Weather Service forecasters. Knowing when, where, and how hard atmospheric rivers will hit is vital to ensuring water supplies and avoiding floods....
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About Us

The San Francisco Bay-Delta is named in the federal Clean Water Act as one of 28 “estuaries of national significance." For over 20 years, the San Francisco Estuary Partnership has worked together with local communities and federal and state agencies to improve the health of California’s most urbanized estuary.

San Francisco Estuary Partnership 1515 Clay Street, Suite 1400 Oakland, CA 94612 (510) 622-2304

Association of Bay Area Governments