Critical protections for endangered fish had little water cost, analysis shows

On the Sean Hannity show this week, Donald Trump told the audience,

California is gonna have to ration water. You wanna know why? Because they send millions of gallons of water out to sea, out to the Pacific … because they want to take care of certain little tiny fish, that aren’t doing very well without water, they have farms here and they don’t get water. It is so ridiculous they’re taking the water and shoving it out to sea.

But according to a 2020 fact sheet from The Bay Institute, the truth is that the 2010-2019 endangered species protections had relatively little water supply impact, much less than routine actions to protect water quality and maintain pumping infrastructure.  And the Trump administration gutted the ESA protections in December 2019.

The fact sheet states, “In 2019 scientists from the Bay Institute, the Nature Conservancy, and San Francisco Baykeeper analyzed Delta exports by the State Water Project (SWP) and Central Valley Project (CVP) and Bay inflow for the 2010-2018 water years.” Baykeeper “extended the analysis through the 2019 water year.”

The scientists’ analysis of the 2010-2019 water years showed that the previous Delta smelt protections limited exports on only 10% of days.  Since the export limits only kicked in when Delta inflows were low, the “water wasted to the sea” to protect Delta smelt was much lower — only 1% of total Central Valley runoff. Water “wasted to the sea” to protect salmon was only 2% of total Central Valley runoff.

The 2010-2019 endangered species protections kicked in at critical times for spawning and rearing of Delta smelt, and for outmigration of endangered winter and spring run Chinook salmon.  The Trump administration’s new rules eliminate all limits on the number of adult Delta Smelt that can be killed at the Delta pumps, and weaken or eliminate many protections for salmon.  The Natural Resources Defense Council called the new rules “A Plan for Extinction.”

Below are the graphs from The Bay Institute fact sheet, and their associated captions:

Limitations Governing Exports, 2010-2019: the percent of days that SWP and CVP exports in the Delta were governed by each limitation. “Water Quality Protections” consist of state regulations to protect water quality for a broad array of municipal, industrial, agricultural and environmental uses. “Endangered Salmon” consists of days when exports were limited in order to protect salmon or of days covering both salmon and smelt; “Endangered smelt” consists of days when exports were limited only for endangered smelt. “Capacity and Maintenance” consists of days when pumping was reduced due to maintenance, full canals or reservoirs, or low demand; the only reason export pumps were ever shut down completely were for capacity or maintenance reasons, not for fish and wildlife protection.

End use of 2010-2019 Central Valley Runoff: this pie chart shows percent of unimpaired runoff to San Francisco Bay from its Central Valley watershed. “Net Diversions”  consists of total diversions (Delta exports, in-Delta diversions, and diversions upstream of the Delta), minus water reuse, imports from other river basins, and releases from prior year storage. “Water Quality Protections” consist of state regulations to protect water quality for a broad array of municipal, industrial, agricultural and environmental uses. “Endangered Salmon/Smelt” consists of actions to restrict exports to prevent jeopardy to these species. “Uncapturable” consists of flows that exceeded the physical capacity of the SWP and CVP to pump, convey or store exports from the Delta; some of this water also helped to meet “Water Quality Protections” and “Endangered Smelt” needs.

(Reprinted with permission.)


Gregory J. Reis, Jeanette K. Howard, and Jonathan A. Rosenfield, 2019,  “Clarifying Effects of Environmental Protections on Freshwater Flows to—and Water Exports from—the San Francisco Bay Estuary,” San Francisco Estuary and Watershed Science 17-1: 1-22. Available at:

4 thoughts on “Critical protections for endangered fish had little water cost, analysis shows

  1. This excellent analysis put into perspective the scale of Central Valley water passing through the California Delta that is “lost to the sea” or “wasted on endangered species” while massive and ever increasing amounts of water are exported for the growth of federally subsidized, exported crops in the San Joaquin Valley. And all this is happening while the California salmon fishing industry disappears because there is no water left for fish.

  2. Delta Salt Water Diet – The Delta needs to be put on a salt water diet. Through our shipping channels that are constantly dredged, we are importing to much salt water into the Delta. Tidally Controlled Louvers that open to let fresh water out, and close as sea water rises plus simple shipping locks can effectively restrict the Delta’s salt water, while keeping the north 1/2 of the Benicia bridge totally open for free travel of small water craft and marine life.

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