A Delta smelt. (Photo: USFWS/Peter Johnsen)

Water battles in the Sacramento-San Joaquin Delta have been fought over a basic question: as the state’s thirsty cities and farms demand more Delta water, is there enough left for endangered fish like the Delta smelt and chinook salmon?

In a report released today from the Bay Institute, environmentalists argue that the damage being done to the Delta ecosystem from removing water isn’t fully being measured.

Two-thirds of Californians get their water from the Delta, the inland complex of islands and channels where the Sacramento and San Joaquin rivers come together, carrying runoff from tributaries and the Sierra Nevada snowpack. Two huge plants in the southern Delta can pump out tens of thousand of gallons of water per second, sending most of it to San Joaquin Valley farms and Southern California cities.

The water heading to the pumps contains fish. To prevent the fish from being ground up by the pumps, the water flows through special screening facilities, the Skinner Fish Facility and the Tracy Fish Facility. As many as 15 million fish per year are “salvaged” or captured at these screens. The fish are then loaded into trucks and released elsewhere in the Delta.

The problem, says Jon Rosenfield, a biologist with the Bay Institute, is that freshwater also contains smaller organisms. “The salvage facilities don’t count fish eggs or really small larval fish,” he says. “You can’t remove between 50 and 70 percent of the water in a system and not take out a very large fraction of the food that’s in that water.”

The report authors argue that removing organisms at the bottom of the food chain has a huge impact. “We have an ecosystem that’s in a free fall and we’re making the situation worse by exporting the fish food,” says Rosenfield.

Rosenfield also points to the fish that get eaten before they get to the salvage facility. “Before they get to the screens, there are whole bunch of predators,” he says. “The actual numbers of fish and fish food that are getting removed from the system are from 4 to 10 times higher than the number of fish that get counted.”

Whether or not Delta smelt and other fish survive the salvage process is another big question. “Very few fish are able to tolerate that much handling and transport in a truck,” says Rosenfield. Researchers have attempted to measure how many fish are killed in the process and operators at the pumping facilities are currently looking at ways improve the survival rate of the fish that are caught. Thanks to extremely wet weather last year, the Delta smelt population rebounded slightly after a decade of decline.

Some water agencies claim that pumping freshwater isn’t to blame for the decline of endangered species. “We’ve focused on the pumps excessively. We’ve ignored the issues of toxics and predators and other things,” says Jason Peltier of the Westlands Water District, a largely agricultural district that relies on Delta water.

“The main driving factor for fish decline is lack of food in the system, driven by Asian clams in the western Delta that are filter feeders. That’s taking a lot of the food chain. In addition, maybe the discharge of ammonia from wastewater treatment plants has disrupted the lower end of the food chain,” he says.

The science of endangered species recovery is back in the spotlight this year, as the state writes two plans for the future of the Delta, the Delta Plan and the Bay Delta Conservation Plan. “This is the most critical period in two decades. California is coming to grips with the fact that its water supply system is unsustainable,” says Rosenfield.

One of the plans includes a proposal for new water pumping infrastructure. A massive, multi-billion dollar tunnel would route water through Delta, making the southern pumps unnecessary.

Rosenfield says he’s not against it in principal, but says it will only work “if it’s designed right and if it’s limited in the amount of water that it diverts from the Delta. It’s not really going to solve the problem unless enough water is left in the Delta.”

Delta Pumping Has Unmeasured Cost for Endangered Fish, Environmentalists Say 26 March,2012Lauren Sommer

  • While this study acknowledges other factors that impact the fish populations, it continues to lay the primary blame on pumping operations in the Delta that send water to 25 million Californians and to farms that produce a healthy and safe food supply. It ignores reports that indicate that losses for salmon from predators are greater than those numbers salvaged at the Delta pumps.  Salmon populations are well-documented to cycle up and down and have gone through three of these cycles since 1983.  Interestingly, a four-year average of exports volumes leading up to high population versus low population shows that export volumes really don’t matter.  Exports were almost exactly the same over the years that population peaked as they were when populations were low —4.85 maf for the high populations and 4.92 maf for the lows, or one and a half percent difference. Clearly, something else is affecting salmon beyond exports.
    No one is denying that the numbers are startling to the casual observer. However, the study authors ignore the fact that Environmental Protection Agency officials denied endangered status to splittail, one of the fish species touted in the study, because of its high population. EPA biologists repeated their findings when discounting the high numbers salvaged at the pumps in 2011. In summary, the authors use numbers they select to support their position that the pumping of water from the Delta should be curtailed. This reasoning does not help to resolve the water issues we face today in California.

    Mike Wade
    California Farm Water Coalition

  • Chris Gulick

    Here we are again reading as Jason Peltier and Mike Wade( both well paid, well spoken advocates of an elite segment of Central Valley agriculture) point their fingers at everything except the pumps and the destruction they undoubtably do.
    Obviously their arguments are designed to promote the need for a 30 Billion dollar Peripheral Canal/Tunnel complete with “state of the art” fish screens that, in theory, will prevent the carnage that occurs in the south Delta pumps with their totally inadequate screens.
    Keep in mind, the pumps in the south Delta will NOT be removed or made inoperable as a result of building a conveyance in fact they will continue to be used regularly.

    Does anyone else see the glaringly obvious question ?

    Before we go thinking about spending what is bound to be in excess of 30 BILLION DOLLARS to build a new conveyance that will take years if not decades to complete, shouldn’t we install “state of the art” screens on the existing pumping station for a small fraction of the cost ?
    That would certainly minimize the immediate problems cited in this article.

    Unless, by installing screens on the south Delta pumps we would lessen the perceived/contrived need for a Peripheral Canal/Tunnel. That’s my bet.  

    • Anonymous

      Actually the new state of the art screens would not really work in the south delta because of the tidal flows and requirements for the South delta Farmers.  For the state project the screens  alone would be $400 Million and you would have to put in the structures that would be over 1/4 mile long and they would have to operate on a tidal basis so there would have to be structure to open and close the intakes for that length. Then there is the pond weed and water hyacinth that would clog them and reduce the flow significantly. The Federal project would be just as complicated becuase they own so little land it would make screening almost impossible in their small intake channel.  You would also still have the larval and egg stages of the indelta fish.  That is one of the main considerations of moving the intakes up to the Sacramento River, that would get the endangered fish out of the pumps at all stages of their lives and the Sacramento River is also where the water rights reside for the State and Federal projects.  If you want to continue to throw money away without fixing anything then by all means propose a way to get the screens to keep everything out and not get clogged, it would be a really good research project for one of your intellect to solve in now time at all where most of the best researcher can’t. 

      • I guess it is impossible for the Feds to buy land?  Come on, there are always alternatives derp

  • While Mike Wade mentions salmon, he does not mention smelt.  There are peer reviewed studies that say how much water is needed for the Delta to keep ecologically viable.  His facts about the EPA not listing a fish is erroneous, as it is the Fish and Wildlife Service that lists species under the Endangered Species Act.

    No one says imports are the only cause of low numbers of salmon and smelt, and the Fish and Game people wanted a no-limit fishery for striped bass, because they are predators of native fish, but the public didn’t want that.

    If the soil is full of selenium, maybe you should not farm it.  If LA needs more water, maybe they should try population limits or desalination.

    • My comment regarding EPA listing species under the Endangered Species Act was simply a misstatement.  And plenty of data exist that show Delta smelt are significantly impacted by stressors other than the pumps, which was the basis for both the smelt and salmon biological opinions.  In his decision to remand the Delta smelt biological opinion, Judge Oliver Wanger relied on testimony showing that the absence of food availability due to ammonia pollution was a major factor in Delta smelt viability.Mike WadeCalifornia Farm Water Coalition

  • Anonymous

    One VERY Basic thing is wrong with this article, 70% of the water in the delta STAYS and Flows OUT through the bay, it does not get exported – a little agenda there to cause such a lie? And what about the AG diversions in the Delta that are unscreened?  I know it’s called fertilizer and the farmers have a right to that too as well!  I really get tired of the environmental lies and misinformation that is given out.
    Some facts – Delta inflows average almost 30 Million Acre Feet (MAF
    Federal and state pumping plants historically average 2.5 MAF  for a total of 5 MAF so you do the math and you will see that 5 is NOT 1/2 of 30 unless this is some new enviro math that I’m not aware of!


Lauren Sommer

Lauren is a radio reporter covering environment, water, and energy for KQED Science. As part of her day job, she has scaled Sierra Nevada peaks, run from charging elephant seals, and desperately tried to get her sea legs – all in pursuit of good radio. Her work has appeared on Marketplace, Living on Earth, Science Friday and NPR’s Morning Edition and All Things Considered. You can find her on Twitter at @lesommer.

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