Dave Rosgen


Born c. 1942. Education: Ph.D. in fluvial geomorphology.

Addresses: Office —Wildland Hydrology, 11210 N. County Rd. 19, Fort Collins, CO 80524. Website —http://www.wildlandhydrology.com.


Joined U.S. Forest Service, 1960s; left Forest Service, 1985; started Wildland Hydrology Consultants, c. 1985; published paper in Catena, 1994; published book, Applied River Morphology, 1996.

Awards: Outstanding Achievement Award from the U.S. Environmental Protection Agency, 1993; Leopold Conservation Award from the Federation of Fly Fishers, 2001.


If you have ever seen a stream confined in a man-made channel, or walked along a river and discovered a crazy quilt of concrete lining the bank, you can understand why Dave Rosgen and his ideas are so popular. He has become the leading figure in the science of restoring rivers. "People think we have natural, stable rivers all over the place," he told writer Jessica Snyder Sachs of National Wildlife. "In fact, we've altered most of them in one way or another." Rosgen's mission is to alter them once more, but in ways that mimic their natural behavior. His methods have become very popular, although he has critics who question whether those methods are really as effective as he claims.

Born in northern Idaho and raised on a ranch, Rosgen went to college in the early 1960s, then went to work for the U.S. Forest Service as a watershed forester in the mountains of his home state. What he saw made him angry. "The valleys I knew as a kid had been trashed by logging. My trout streams were filled with sand," he recalled to David Malakoff, a writer for Science. He suspected logging and road-building were harming streams, but he had no measurements to prove it, so his bosses did not listen. He studied soil types and water flows in the streams, and he noticed that some types of streams resisted damage better than others.

Starting in the late 1960s, Rosgen teamed up with a leading river science researcher, Luna Leopold of the University of California, Berkeley, and used Leopold and others' work to develop a system for classifying rivers. Rosgen's system looks at rivers' width, depth, slope, sediment and other aspects, then puts them into nine major categories. The system, he decided, could identify natural, stable channel shapes—and rivers could be restored to those shapes even after erosion or re-engineering had altered them.

Rosgen left the Forest Service in 1985 over a disagreement about a dam he opposed, and retreated to his cattle ranch near Fort Collins, Colorado. It ended up being a turning point in his life, because it freed him to work on his ideas full-time. He founded Wildland Hydrology Consultants, a company that restores rivers and offers classes based on his methods.

A previous generation of river engineers would try to prevent flooding and fix eroded river banks by running rivers into narrow concrete channels, or by installing rip-rap along the banks—usually ugly piles of concrete, sometimes even junked cars. Rosgen, instead, will drop dead trees or boulders in strategic places to help direct the stream's flow. He may also run a bulldozer through a stream bed, trying to get the stream to flow at just the right angle, or grade, so that it flows fast. He might even out an unnaturally steep bank, or plant small trees on the bank to fight erosion or the effects of cattle-grazing. If all goes well, grass will grow on the banks, fish will return, and the river will flood less often. "I try to copy what works in nature," he explained to Time 's Pat Dawson. His methods can also cost as little as one-fourth the prices of most structures built to control floods.

The idea of making a river more "natural" by running a bulldozer through it horrified some. But when Rosgen rebuilt stretches of the troubled San Juan and Blanco rivers in southern Colorado, his methods seemed to work, and they caught on. The National Research Council issued a report on river restoration in 1992 that essentially endorsed his methods. Two years later, Rosgen published a paper describing his system in the prestigious journal Catena . It declared that there were seven major types of streams and dozens of subtypes, such as Type A streams (steep, narrow and rocky) or E channels (gentle, wide, and meandering). The article also explained how restorers could forecast how a stream's shape might change due to erosion or other stresses, and it explained how to alter a stream so it returned to a stable state often seen in untouched rivers. Rosgen expanded his ideas into a book, Applied River Morphology, published in 1996.

Since then, Rosgen has taught his methods to more than 12,000 people, including many natural resource managers for government agencies and nonprofits. The pricey classes promise to teach students "how to think like a river," according to Malakoff's profile of Rosgen in Science. "Your job is to help the river be what it wants to be," Malakoff quoted Rosgen as telling his students. Rosgen himself has reconstructed about 100 miles of rivers, and others have used his methods to reconstruct many more. Many government agencies are so impressed, they now refuse to fund river-restoration projects unless they use Rosgen methods.

Critics of Rosgen and his effect on river restoration question whether his methods are really based on good science. Some say his system oversimplifies how rivers behave. In 2003, two government researchers concluded that a competing method of analyzing streams did better than Rosgen's methods in analyzing a Wisconsin river. (Rosgen says the researchers did not really understand his method.)

Some projects that followed Rosgen's methods have failed, leaving streams eroded and full of silt. "There are tremendous doubts about what's being done in Rosgen's name. But the people who hold the purse strings often require the use of his methods," Peter Wilcock, a geomorpologist who specializes in river dynamics at Johns Hopkins University, told Science 's Malakoff. Some criticism is not aimed at Rosgen's work exactly, but more at the way others use it. Detractors of his methods say they are so simple, they give people the feeling that they know more about rivers than they really do, and that Rosgen's inspiring charisma can make people too zealous about his system. (Rosgen admits his ideas have been misused, and he says he has increased the amount of training he offers.)

A glowing profile in Time in 2004 helped increase Rosgen's stature. River restorers, whether they love or hate his work, say he is the dominant figure in their field. "It's almost impossible to talk about the subject without his name coming up," David Montgomery, a geomorphologist at the University of Washington, Seattle, told Science 's Malakoff.

Selected writings

Applied River Morphology, Wildland Hydrology, 1996.



American City & County, January 1, 1996.

National Wildlife, June/July 2002, p. 10.

Science, August 13, 2004.

Whole Earth, Summer 1998, p. 37.


"Dave Rosgen," Federation of Fly Fishers, http://www.fedflyfishers.org/Conserve/Leopold.htm (November 28, 2004).

"The Stream Saver," Time, http://www.time.com/time/2004/innovators/200404/rosgen.html (November 28, 2004).

Wildland Hydrology Consultants, http://www.wildlandhydrology.com/index.htm (November 28, 2004).

Additional information was obtained from a press release from Wildland Hydrology Consultants.

—Erick Trickey

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