Marty McDonnell's livelihood lies on the waters of the Tuolumne River - somewhere between hydropower dams high in the Sierras and water faucets west in San Francisco.
He makes his living running rafting trips on some of the most rugged white water left in the United States. He's so fond of the Tuolumne that he's trying to drum up business for winter river trips. ''I like weather . . . the thunder coming down in the canyon,'' he explains, gesturing toward the Tuolumne.
But Mr. McDonnell also keeps his eye on thunder of a different sort on this river. A battle between environmentalists and urban and industrial development concerns has wrapped this pristene river in controversy for the last 80 years.
The birthplace of the modern environmental movement, the Tuolumne (pronounced TWAL-a-me) was the object of the nation's first conservation campaign when Sierra Club founder John Muir tried unsuccessfully to prevent construction of the Hetchy Dam within the boundaries of Yosemite National Park.
Dammed and tapped for hydropower at several points, the river remains at the center of environmental controversy. And while the Tuolumne may not exactly be a household word, it is viewed as a bellwether of environmental causes today for two reasons:
* It is a test case that will determine whether the National Wild and Scenic River Act - a 15-year-old environmental law designed to preserve untouched river systems - will be exercised by Congress. Protective status has not been granted to any of a dwindling number of qualified rivers for five years. Environmentalists consider the Tuolumne the case that can get the ball rolling again.
* Crucial bipartisan support for preservation of the river was won this month for the first time in the 80-year struggle to prevent further development on the river. The support of Republican Sen. Pete Wilson, considered a turning point for the movement, was won after considerable campaigning by northern Californians who have waged the most concentrated environmental drive in the state today.
The Tuolumne River Preservation Trust, a coalition of business, local governments and environmental groups, has mounted a sophisticated, single-issue campaign to preserve about 80 miles of untouched Tuolumne wilderness. The tactic has meant political compromises - of other wilderness areas, for example - that have angered different environmental causes.
But, as Mr. McDonnell explains it, river supporters say that to get anything done they must focus on the single issue. ''Environmentalists are typically too impatient, but they can't win a political battle on emotion. They're fighting a system that has been centered around development. And in order to get a bill passed they have to show some movement from a radical position . . . ideally we'd like no development, but you have to allow some.''
''The wild and scenic system remains sort of an orphan of Congress and the conservation community,'' says John Amodio, executive director of the Tuolumne River Preservation Trust. A Carter administration study ''found only 2 percent of all river miles still qualify to be designated as wild and scenic. And only 8 percent of those qualifying miles have been designated.
''So less than 2/10 of 1 percent of America's river mileage is protected for natural values. The Tuolumne is clearly the bellwether of whether a river can be protected. The feeling is if we can't protect this, what can we protect?''
The main opposition to wild and scenic status comes from the Modesto and Turlock irrigation districts, which have a proposed new hydroelectric system under study. (Even their water-rights partner - San Francisco - has joined the preservation drive.) But the irrigation districts, which supply water and electricity for Central Valley residents, farmers, and many canneries, want the new 390-megawatt facility on the Tuolumne to help bring more of the costs of power under local control, says Larry Klein, director of the Clavey Wards Ferry dam project.
The districts already offer some of the cheapest electric rates in the nation , but says Mr. Klein, half of their power has to be bought from outside sources (Pacific Gas & Electric and from San Francisco.)
Disputes over the new dam project center on dislocation of family camps and residences where the reservoir would inundate valleys, the effects on fish and other wildlife in the area, and the effects on some of the nation's roughest white water. But wild and scenic status would prevent any further development. Mr. Klein says the districts' position is to oppose wild and scenic status on the grounds that his study of the proposed project may show it won't have a harmful effect on the river area.
Environmentalists will admit that development has enhanced white water on the river. But they say that man has already struck a delicate balance on the Tuolumne. Ninety percent of its irrigation potential and 70 percent of its hydroelectric potential have already been tapped, while navigable white water, wildlife, and wilderness remain for man's enjoyment along certain stretches.
Because the river is already developed, some would claim it is no longer wild. But by using that criterion, says John Amodio, ''You might as well dam the Grand Canyon'' because the Colorado River is already so highly developed.