Silvicultural activities in the Pacific Northwest introduce various levels of sediments and debris into streams, often degrading spawning habitats of salmonid fishes. In these mountain streams spawning takes place in riffles where the water velocity is usually 1.5 to 2.5 ft/sec and water is 6 to 36 inches deep. The substrate in these riffles are ideal habitats for aquatic insects which in turn respond adversely to excessive sedimentation. For these reasons, the study of spawning habitats could provide a relatively simple and sensitive indicator of watershed management impacts. Simple but reliable procedures are needed to monitor spawning substrate to assess the level of these impacts. This paper presents a preliminary rationale for conducting a monitoring program to assess the impact of watershed management activities on stream spawning habitats.

Ecosystems Modeling and Analysis Branch, Corvallis Environmental Research Laboratory. Department of Fisheries and Wildlife, Oregon State University. "Report originally prepared for EPA Region X." "February 1979." Includes bibliographical references (page 13).