Study: Water Diversion May Not Help California Smelt

Published April 2, 2010

The diversion of water from California’s Sacramento-San Joaquin Delta to protect endangered fish at the expense of Northern California farmers is scientifically justified but of questionable value, a National Academy of Sciences panel has concluded. Both sides in the fish versus farmers battle in Northern California are heralding the findings as supporting their position.

The federal government is currently limiting the amount of water farmers may draw from the delta system and diverting it instead to assist delta smelt, chinook salmon, steelhead, and green sturgeon. The battle over water rights between regional farmers and conservationists has been boiling over for years.
Questionable Effectiveness
According to the NAS report, “The committee concluded that in winter, high reverse river flows from high levels of pumping probably adversely affect smelt. Therefore, reducing the high reverse flows to decrease mortality of smelt is scientifically justified. However, the data do not permit confident identification of when to limit reverse flows of the rivers  or a confident assessment of the benefits fish receive by reducing reverse flows, the Committee found.”
The report found chinook salmon, steelhead, and sturgeon are adversely affected by farmers drawing water from the delta system, but it noted other environmental factors may be affecting the situation too.

Importantly, the report concluded the effectiveness of limiting the water drawn by regional farmers is uncertain even though scientifically justified.

“The committee also found it difficult to ascertain the extent to which the collective watershed and tributary actions will appreciably reduce risks to the fishes within the watershed or throughout the entire river system and recommended a quantitative framework be created to assess survival,” the report explained.

Both Sides Claim Victory
William “Zeke” Grader, executive director of the Institute for Fisheries Resources, says the NAS findings support his position that the water available to farmers should be restricted and the federal government should continue to divert water to aid fish.

“The study basically provided an additional layer of scientific approval of the biological opinions that were established on the water operations impact on the salmon and the delta smelt,” said Grader.

But Heartland Institute science director Jay Lehr, Ph.D., says farmers are being forced to pay the price for overly aggressive environmental protections.

“The study confirms that many factors are contributing to the decline of delta smelt and salmon, including the spread of aggressive, nonnative striped bass,” said Lehr. “Farmers should not be denied the right to make a living when there is plenty of water for both farmers and fish and the diversion of unnecessary amounts of water for fish is not even shown to be significantly helping the fish.”
Sarah McIntosh ([email protected]) teaches constitutional law and American politics at Wichita State University in Kansas.