Environmentalists here say they are keeping an eye on Los Angeles for backsliding, but they acknowledge that the new efforts will make a significant difference.

Image As part of a project to restore water to the Owens Valley, a dam redirects water going to Los Angeles, causing it to flow into the Owens River. Credit... J. Emilio Flores for The New York Times

As winds whipped across Owens Lake on a recent afternoon, Mike Prather of the Owens Valley Committee, which along with the Sierra Club took Los Angeles to court over the environmental fallout of its water policies, marveled at sandpipers, American avocets and other birds frolicking in the shallow pools created by the irrigation.

“This work will bring back more and more of them,” Mr. Prather said, savoring the twist in the battle that means water once intended for Los Angeles will feed the lake.

“It’s Owens Valley’s turn to stick its straw in L.A.’s water,” he said.

Court rulings and the threat of legal action have largely forced Los Angeles’s hand in dealing with its past water moves, but city leaders say they are also intent on doing the right thing in keeping up a vital source of water while avoiding further damage to the Owens Valley.

H. David Nahai, president of the board that oversees the Los Angeles Department of Water and Power, said Los Angeles was looking for less adversarial ways to resolve differences over the valley, which provides 40 percent to 60 percent of the city’s water supply, depending on the snowfall in the mountains.

“We can’t change the past, but we can shape the future,” said Mr. Nahai, one of five board members appointed by Mayor Antonio R. Villaraigosa, who promised a friendlier approach to the valley when he took office in July 2005.

Susan Cash, the chairwoman of the Board of Supervisors of Inyo County, where the Owens Valley is located, said animosity toward Los Angeles had lessened since the early 20th century, when the water diversion was made possible by the purchase of much of the valley by less-than-forthcoming city operatives.