The Effect of Stream Cleaning on Salmonid Habitat and Populations in a Coastal Oregon Drainage

Abstract

Abstract Habitat conditions and use by anadromous salmonids were evaluated in five reaches of Upper Lobster Creek, a major stream system in the central Oregon Coast Range, to determine the effect of different levels of stream cleaning. Stream clearance associated with post-World War II logging practices and a 100-year flood event that occured in 1964 severely altered channel configurations and loading patterns of large woody debris. This caused the subsequent removal of log jams. An uncleaned reach had large amounts of woody debris and the highest density of pools, greatest percentage of off-channel habitat, and highest salmonid use. In contrast, a totally cleaned reach had the lowest density of pools and lowest salmonid use. Rehabilitated sections of a reach that had been partially cleaned showed increases in density of pools and salmonid use compared to the remainder of the partially cleaned reach. Retention of standing timber in the riparian zone and maintenance in instream accumulations of large woody debris is recommended to allow streams to reach their productive potential for anadromous salmonids. West. J. Appl. For. 2(3):84-87, July 1987.