Chris Caskey, The Union Democrat

The Oakdale Irrigation District agreed this week to sell Stanislaus River water in a one-year deal to the San Luis and Delta Mendota Water Authority, which serves multiple districts with agricultural customers in the western Central Valley.

Under the agreement, OID will sell about 40,000 acre-feet of water from the Stanislaus River at $100 per acre-foot and send the water down the river to the Delta, where it will be pumped to its destination.

The Tuolumne Utilities District, Tuolumne County's largest water provider, also receives its water from the Stanislaus River system through a contract with PG&E.

Pete Kampa, TUD's general manager, said the sale won't affect TUD's supply but could further lock up river water supplies in the future on the Stanislaus system.

"Every drop that leaves the watershed, that is not water that can be used (locally)," he said.

TUD has discussed whether it should seek rights to water in the river basin. The district, which has no water rights, now receives about 17,500 acre-feet of water from the Pacific Gas and Electric Co., which operates hydroelectric power projects on the Stanislaus River's South Fork. The water is stored in Pinecrest and Lyons reservoirs, owned by PG&E.

Most of the water flowing down the Stanislaus is spoken for.

Oakdale and the neighboring South San Joaquin Irrigation District, have senior water rights on the river, predating the state's 1914 Water Commission Act. Under a contract with the U.S. Bureau of Reclamation, they're entitled to about 600,000 acre-feet of water a year. OID uses about 85 percent of its allotment, so could sell the difference.

SSJID already sells a portion of its water to Stockton East Water District.

The Oakdale Irrigation District is also considering water sales to Bay Area communities, and approved a proposal to annex farmland near Knights Ferry where it will sell water for irrigation.

John Buckley, executive director of the Twain Harte-based Central Sierra Environmental Resource Center, who monitors OID and the SSJID's activities on the river, is concerned the Stanislaus is being over committed.

The incremental amounts of water taken out of the river "all adds up" when considering environmental impacts, especially in the dry years, he said.

There is less water flow for fish species like salmon and steelhead when more water is removed, he said, adding that lower flows also mean warmer water temperatures and less dilution of contaminants like pesticides.

"All of us in California benefit from agriculture," Buckley said. "But at some point, the scale of demand will be greater than the water available in the river during dry years."

The water sale was announced days after Kampa and other county officials visited the state Water Resources Control Board to talk with board staff about operational requirements for Pinecrest Reservoir. The state requires Pinecrest be maintained at an elevation of 5,608 feet above sea level, through Labor Day weekend, for recreational purposes. The regulation was set during the federal relicensing of the Pinecrest dam.

TUD and PG&E are asking for more flexibility and say the rule will artificially hamper local water supplies during dry years. Proponents of the lake level requirement, including Buckley, have said TUD needs to fix issues of waste in its water-delivery system, which includes unlined Gold Rush-era canals.

Kampa was upbeat about last week's talks. He said much of the discussion was about introducing new board members and other local supporters to the Water Board staff.

"We plan to continue this process," Kampa said.

A decision on the final lake level is expected no earlier than late spring or summer, according to the water board.