Today the National Research Council’s Committee on Sustainable Water and Environmental Management in the California Bay-Delta released the first of two reports regarding the Sacramento-San Joaquin Delta in California. The report is entitled A Scientific Assessment of Alternatives for Reducing Water Management Effects on Threatened and Endangered Fishes in California’s Bay Delta. It addresses two biological opinions issued by the Fish and Wildlife Service and the National Marine Fisheries Service (“NMFS”) under the Endangered Species Act concerning the operation of the state and federal water projects that serve 25 million Californians.

The National Research Council report focuses on:

  • scientific issues regarding the reasonable and prudent alternatives (RPAs) in the two biological opinions,
  • whether the RPAs might be in conflict with one another, 
  • whether alternatives to the RPAs might be available that would protect the fishes with lesser impacts on other water uses, and
  • the effects of stressors other than water project operations on the fishes.

The Committee reviewed the actions contained in the Service and NMFS RPAs and determined that most of them have a sound conceptual basis. Nonetheless, the Committee concluded there are a number of short-comings in the existing RPAs. For example, with respect to the Service’s RPAs, the Committee determined that there is a weak statistical relationship between the salinity contour measure (“X2”) used in the biological opinion to restrict water deliveries and the size of the delta smelt populations, which makes justification of that RPA difficult to understand. With respect to the NMFS RPAs, the Committee concluded that the scientific support for specific flow targets managing the flow from the Old and Middle Rivers is uncertain.  As noted in a New York Times article on the report, the Committee added that "problems facing delta smelt and chinook salmon are not entirely caused by thirsty farms south of the estuary."

A previous post on this subject, including links to both biological opinions is available here.