By the time endangered spring chinook reach the mouth of the Methow River, a tributary of the Columbia, in late summer, they have traveled 500 miles and passed nine dams in order to spawn. Upstream, the Chief Joseph Dam, which lacks fish passage, blocks further progress up the Columbia. The Methow’s forested watershed offers one of the last spawning places for salmon that make it this far. Until recently, however, those fish faced a final obstacle: The Methow and its tributary, the Twisp, were being diverted into miles of leaky irrigation ditches, leaving both rivers perilously low during dry years. That changed this year, thanks to a court ruling that forces irrigators in the Methow Valley to stop wasting the river’s water.

Fights over whether water should be diverted for farmers or left in the rivers for fish are nothing new in the Northwest, but the Methow Valley is a special case, because of the irrigation district’s long-standing resistance to upgrading its system. “The (district) is sort of the poster child in Washington for waste,” says John Arum, who represented the Wilderness League in the case. Last month’s court ruling follows – and, environmentalists hope, ends – 10 years of labyrinthine negotiations and court battles involving the irrigation district, the Okanogan Wilderness League, state and federal agencies, tribes, and junior water users.

Since 1975, when engineers first decided that lining or replacing the Methow Valley’s century-old ditches could save thousands of acre-feet of water while still delivering the same amount to hayfields, the district had been diverting half the Twisp’s summer flow, drawing the river so low it left fish stranded in pools. In drought years, all the Twisp’s water was diverted, into what Okanogan Superior Court Judge Jack Burchard calls a “dilapidated and poorly managed canal system,” which engineers said delivered as little as one gallon of water to the fields for every 10 gallons taken from the rivers.

By the late 1990s, the mid-Columbia spring chinook had been listed as endangered, and the Bonneville Power Administration came up with $5 million in salmon mitigation funds to replace the ditch system with pressurized pipes, cutting waste to nearly zero. Over a hundred farmers in the lower reaches of the district were switched to wells in the first stage of the project. But once that was done, the district shrank, and its voting membership changed. The remaining members wanted to keep their ditches. They “dug their heels in,” says Bob Barwin, water resources manager for the Department of Ecology’s Yakima office. The rest of the system was never built.

Vaughn Jolley, president of the irrigation district’s board, says the pressurized system would have cost $200 an acre to maintain and operate (the district currently assesses its members at $112 an acre). But there seems to be a deeper reason for the district’s resistance. It’s what Rachel Pascal Osborn, the Wilderness League’s other attorney, calls the “romance of the ditch.” The 26 miles of leaky ditches keep the arid valley green. Pipe the water straight onto the fields, and the rest of the valley reverts to sagebrush desert. Jolley says the loss of the “riparian habitat” along the ditches would damage the environment and “change the culture and custom of the Methow Valley.” But in Washington water law, the ditches’ side benefits aren’t considered “beneficial uses” that justify a water right.

The court ruling, which upholds an earlier order from the state Department of Ecology, restricts the amount of water the district can take from the rivers to about one-third of what it diverted in the 1990s. The department says that if the district curbs its waste, it will still be able to deliver the same amount of water to farms. The decreased diversions have been phased in over the last three years, and last year the state Legislature paid over a million dollars to line some of the ditches. But Richard Price, the irrigation district’s attorney, says the order just does not allow enough water for crops, and that farmers will have to stop irrigating this year before the season ends. He hopes an upcoming engineering analysis, ordered by the state Legislature, will find that the district needs to divert more water.

For now, the extra water will substantially increase the Twisp’s late-summer flow, providing a huge boon to the fish. Because this is the first time anyone has challenged a state restriction of water rights based on waste, the court’s support of Ecology’s order is especially significant. “This decision confirms that water efficiency is mandatory, not optional,” says Pascal.