Document Details

Collateral Damage: A citizen’s guide to fish kills and habitat degradation at the state and federal water project pumps in the Delta

The Bay Institute (Bay Institute) | March 1st, 2012

Large-scale fish kills and habitat destruction aren’t an unusual occurrence at the giant federal and state pumps that export water from the Sacramento-San Joaquin Delta to agribusinesses and cities in the southern half of the state. These events are business as usual.

• Every day, between 870 and 61,000 fish – including from 200 to 42,000 native and endangered fishes – are “salvaged” at the pumps. Most die in the process.

• On average, over 9 million fish – representing the twenty fish species considered in this report – are “salvaged” each year at the pumps. As many as 15 million fish of all species encountered are “salvaged” each year.

• Up to 40% of the total population of the endangered delta smelt and 15% of the endangered winter-run population of Chinook salmon are killed at the pumps in some years. In the first half of 2011, over 8.6 million splittail were salvaged.

• Salvage estimates drastically underestimate the problem. The numbers do not factor in the results of “indirect” mortality, as high levels of export pumping disrupt fish migration, shrink the amount of non-lethal habitat available to fish species, and remove vast amounts of biomass, including fish eggs and larvae too small to be screened at the pumps.

• Export pumping causes the lower San Joaquin River to flow backwards most of the year and removes the equivalent of 170 railroad boxcars of water – and the accompanying fish, other organisms, and nutrients – from the Delta ecosystem every minute.

• Large numbers of fish being entrained is a problem even for species that are not currently listed as “endangered.” Killing large numbers of fish year after year cuts off population growth in response to favorable conditions and can start the species on a downward path to extinction. As the species declines, the population impacts of entrainment become proportionately larger.

• Entrainment is a real problem. But the same interests in the Delta export community who claim that it isn’t also back constructing expensive new conveyance facilities such as a peripheral canal or tunnel to solve the problem that they say doesn’t exist.


adaptive management, Central Valley Project (CVP), endangered species, fisheries, infrastructure, State Water Project (SWP), water project operations

Filter Results






Hydrological Region