The delta smelt may be a small fish with a short life, but it has spawned a decades-long legal battle over water in California.
At issue has been a series of orders under the Endangered Species Act that at times reduce water deliveries from the Sacramento-San Joaquin River Delta to San Joaquin Valley growers and urban Southern California.
Citing the severe state drought, lawyers for the Metropolitan Water District of Southern California are asking the U.S. Supreme Court to reconsider a strict federal rule from the 1970s that calls for curtailing the water diversions to protect the threatened delta smelt and other imperiled species regardless of the cost to humans and the economy.
The reduced pumping "has had a huge impact," said Bob Muir, a district spokesman. Over the last five years, state officials say pumping has been reduced 10% to 30% each year to keep more fresh water in the delta, the only place in the world where the tiny native smelt is found.
In their appeal, the district's lawyers said the amount of water that was withheld during the winter of 2012-13 "would have been enough to supply the entire San Diego region this year."
The justices will meet Friday to consider a long list of pending appeals; the California water dispute is raised in two appeals, one from a coalition of water agencies and the second from Central Valley growers.
The appeals describe California's state and federal water projects as the nation's largest and most important and say their operations have been "substantially curtailed," even during the drought, because they were deemed to threaten the delta smelt, a finger-size fish whose survival is in doubt.
The case has echoes of the famous snail darter case from 1978.
The Supreme Court agreed then to block completion of a Tennessee dam because it threatened to kill off that endangered tiny fish. Afterward, Congress amended the law to give more flexibility to federal officials. They were told to consider "reasonable and prudent" steps that would be "economically and technically feasible" in saving a threatened species.
But in the delta smelt case, federal officials and the U.S. 9th Circuit Court of Appeals decided that what is "reasonable and prudent" does not include weighing the effect on humans or the economy.
Last year, the 9th Circuit in effect backed the pumping limits. In a 2-1 decision, judges rejected legal challenges to the opinions of the Fish and Wildlife Service that required the reduced pumping. Judge Jay Bybee, a George W. Bush appointee, said the law left the court no other choice.
"The 'economic and technological feasibility factor' does not address the downstream impact," he wrote, citing the high court's decision in the snail darter case. "The delta smelt has teetered on the brink of extinction … and the FWS has a duty to protect the viability of the smelt whatever the cost."
Washington attorney Tom Goldstein, representing the California water agencies, called this a legal error that only the Supreme Court can correct. He argued Congress intended that federal wildlife officials weigh the effect on "third parties" before deciding whether cutbacks in water are "reasonable and prudent."
The high court agrees to hear only about 1% of the cases that are appealed, but the California water cases could prove to be crucial tests of the Endangered Species Act. They are State Water Contractors vs. Jewell and Stewart & Jasper Orchards vs. Jewell.
Lawyers for the Natural Resources Defense Council and U.S. Solicitor Gen. Donald Verrilli Jr. urged the court to turn down the appeals. They said the 9th Circuit was correct in saying Fish and Wildlife officials must take reasonable steps to protect an endangered species, regardless of the economic effect.
Kate Poole, an NRDC attorney, said the water agencies have "a long history of exaggerating the impacts" of protecting endangered fish in the delta, including chinook salmon.
"The underlying problem in California is that our demand for water consistently exceeds our supply, even in non-drought years," she said. "Wiping out our native fisheries will not solve this problem."