Evaluation of Instream Fish Habitat Restoration Structures in Klamath River Tributaries, 1988/1989

Ten instream fish habitat techniques were evaluated to determine which most effectively restored salmonid spawning and/or rearing conditions. Structure stability was estimated based on how intact each structure remained (by percent) and its age, we then projected useful life for each structure type. Cost in 1989 dollars was used to determine cost per unit habitat area provided. Observed use by spawners was used to estimate total number of redds per structure (over its life). Cost of providing spawning habitat (cost per redd) was calculated by dividing estimated total redds by structure cost.

We rank structures evaluated in this study (from most cost effective to least cost effective) as follows: Digger Logs, Boulder deflectors, Small Boulder Weirs, Boulder Groups with Woody Cover, Free Boulder Weirs, Large Boulder Weirs, Boulder Groups, Boulder/Rootwad Groups, Boulder/Rootwad Deflectors, Small Boulder Weirs, and Cabled Cover Logs.