SAN FRANCISCO (Legal Newsline)-California environmentalists are appealing a judge's decision to keep active more than 100 long-term water delivery contracts in the agriculturally rich Central Valley.

In an appeal filed Monday in the 9th U.S. Circuit Court of Appeals in San Francisco, the Natural Resources Defense Council and the San Francisco Baykeeper say the decades-long water contracts would harm aquatic life in the Sacramento-San Joaquin Delta.

The groups are appealing a ruling by U.S. District Senior Judge Oliver Wanger in Fresno, Calif., that U.S. Fish and Wildlife Service to rewrite its rules governing the management of the imperiled delta smelt.

They allege that the water-delivery contracts -- based on a 2005 Biological Opinion that has been thrown out by a federal court -- violate the Endangered Species Act.

They are asking the appeals court to have the contracts renegotiated to reflect current science to safeguard the silver-colored fish, which is listed as threatened under the Endangered Species Act.

"These water contracts must be revised to reflect a reasonable level of water diversions, require sensible conservation measures, and protect the collapsing Delta if we are going to fix California's broken water system and restore healthy fish populations," said Kate Poole, lead attorney at the Natural Resources Defense Council.

The water contracts would go to farmers in the Sacramento Valley.

Under some of the agreements, they would be allowed to continue diverting more than 2.2 million acre-feet of water annually, while other contracts being challenged allow the diversion of over 300,000 acre-feet of water from the Delta to San Joaquin Valley growers for the next 25 years.

"We're talking about agreements that hand over California's real wealth, its water, for decades to some growers watering desert soils full of toxic minerals for a fraction of the real value of that water, all at taxpayer and urban water users' expense," said Earthjustice Attorney Trent Orr. "These contracts would be locked in for 25 years, and many for 40 years."

From Legal Newsline: Reach staff reporter Chris Rizo at chrisrizo@legalnewsline.com.