Habitat and channel changes after rehabilitation of two coastal streams in Oregon
Fisheries Bioengineering Symposium: American Fisheries Society Symposium 10
Colt J;White RJ;
American Fisheries Society
Two stream reaches of the upper Nestucca River basin, severely degraded by a dam failure, roads, and stream cleaning, were structurally modified in 1986. In the upper Nestucca River, which drains 51.3 km2, 77 structures that fully spanned the stream and 120 that partially spanned it, as well as 9 off-channel areas, were constructed along 8.5 km of stream. In Elk Creek, a drainage of 26.6 km2, 37 fully spanning and 55 partially spanning structures, including the creation of 7 off-channel areas, were constructed along 1.9 km of stream. Follow-up evaluations in 1987, after two storms caused flows greater than would be expected to recur with a 1-year interval, showed substantial changes in habitat and channel conditions favoring anadromous salmonid use. Pool habitat, the most important rearing component for salmonids, increased significantly between pre- and postenhancement evaluations. Pool area increased approximately two- and fivefold, and pool volume increased from 25 to 48% and from 14 to 46%, respectively, in the upper Nestucca River and Elk Creek.