The U.S. Supreme Court has left in place limits on water exports from the Sacramento-San Joaquin Delta to protect the Delta smelt.
The justices on Monday rejected appeals from San Joaquin Valley farmers and urban water districts that had challenged water-pumping restrictions put in place by the U.S. Fish and Wildlife Service in 2008 to protect the 3-inch smelt.
The 9th U.S. Circuit Court of Appeals in San Francisco last March upheld the Fish and Wildlife Service's 2008 biological opinion that controls were needed on the use of massive pumps that move water from Northern California through the delta and on to farms and cities to the south. Under the biological opinion, water exports are cut back at times of year when smelt are observed in the vicinity of the pumps.
U.S. District Court Judge Oliver W. Wanger of Fresno invalidated the biological opinion in 2010, finding that the pumping restrictions were an "arbitrary and capricious" measure with an inadequate scientific basis. He also ruled that the Fish and Wildlife Service had failed to adequately consider the human impacts of the pumping, but allowed the agency's measure to take effect during appeals.
The smelt case is one of two endangered species cases that have led to limits on delta pumping and years of litigation. The other centers on endangered and threatened Central Valley salmon, steelhead and other species. Wanger presided over that case, too, and struck down a biological opinion from the National Marine Fisheries Service that prescribed pumping limits to protect migrating fish.
Last month, the 9th Circuit reversed Wanger on the salmon case, too. The plaintiffs in that case are also expected to seek Supreme Court review of the 9th Circuit ruling.
This post includes reporting from the Associated Press.