Tuesday, Jun. 08, 2004

The Stream Saver

Dave Rosgen
Dave Rosgen, his smile shaded from the midday sun by the brim of his cowboy hat, moves easily along a branch of the main channel of Colorado's Blue River, casting his fly rod. One after another, big rainbow trout take his flies, jumping and fighting the line until he plays each one out to the bank, removes the hook and gently returns the fish to the clear, cold water. Rosgen, a hydrologist, helped bring this stretch of river back to life. The land along the water here had been hammered by years of cattle grazing, the banks eroded after willows were removed to make way for more hay. At the request of the landowner, Rosgen dragged in boulders and chunks of dead trees, placing them strategically to regulate stream flow. He engineered the streambed to just the right grade for optimum flow velocity, and lined it with clean gravel quarried from the property. He transplanted thousands of willow saplings to the area, reversing decades of brush-clearing efforts. The once steep banks are now grassy and gently sloping, almost parklike. Eagles soar overhead, scouting the rich fishery below.

Rosgen's ideas on river restoration, which at one time ran against the current, are now mainstream. The traditional Western reaction to bank loss used to be riprapping — fortifying the banks with chunks of broken concrete or the bodies of junked cars. Rosgen saw that as absurd and destructive. Instead, he studies the geological features of the streambed to determine its ideal "meander geometry" — the way the stream should flow — thus preventing sediment buildup that could block the channel or erode the banks. He then uses natural materials to give the river a kind of eco — makeover. "I try to copy what works in nature," he says.

Rosgen's drive to restore rivers was born of rage. As a young Forest Service worker, he was assigned to inspect an area in his native north Idaho. There, he saw a pristine stream that had been ruined by runoff from timber clear cutting. Rosgen lost his temper, eventually quit the Forest Service and started his own stream-restoration consulting enterprise. Federal agencies that had ignored his complaints are now among the clients that pay Rosgen to teach employees about doctoring streams. He retreats between trips to his horse-ranch headquarters north of Fort Collins, Colo. These days, the man in the white hat doesn't feel quite so much like the Lone Ranger.