What Are Downstream Effects? How Can Downstream Effects Be Assessed? Using Aerial Photographs to Monitor Changes in Channel Conditions

Grant, Gordon. 1988. The RAPID technique: a new method for evaluating downstream effects of forest practices on riparian zones. Gen. Tech. Rep. PNW-GTR-220. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 36 p. The RAPID (riparian aerial photographic inventory of disturbance) technique is a method for using measurements made on aerial photographs of patterns of riparian canopy disturbance to evaluate changes in channel conditions through time and to link such changes with their possible upstream causes. The RAPID technique provides resource specialists and managers with a relatively quick way of identifying stream reaches that are chronically or recently disturbed by a variety of channel processes, including increased peak flows and sedimentation from point and nonpoint sources. With examples from western Oregon, this paper describes how to apply the RAPID technique and analyze the results to evaluate downstream or cumulative effects of forest practices.