Habitat - Fish Passage Technical Assistance
Date Published: March 2000
Number of Pages: 99
Author(s): Eric Gower, Ethan Espie, Brian Benson and Paul Sekulich
The Department of Fish and Wildlife manages over 840,000 acres, to preserve, protect and perpetuate the state’s valuable fish and wildlife resources (RCW 75.08.012, RCW 77.04.055, RCW 77.12.010). In order to maximize accessibility to these lands and other areas for all citizens, several hundred Department of Fish and Wildlife Access Areas have been constructed. Due to the increasing interest of the agency and public in factors affecting fish resources, the Salmonid Screening, Habitat Enhancement and Restoration Division (SSHEAR) initiated an inventory of all fish passage structures (e.g culverts, dams, fishways, lake screens) and unscreened irrigation diversions on agency lands. Potential habitat gain was assessed for features identified as fish passage barriers.
A priority index for order of inventory was calculated for each wildlife area according to the ranking of four separate factors: the number of estimated fish passage problems, fish species status (potential ESA listings or at-risk SASSI stock status), species mobility (resident and/or anadromous fish species), and interest (high profile fish passage issues of public concern). Based on this prioritization, the Olympic Wildlife Area ranked second in priority for western Washington.
Fish passage barriers alone prevented access to 7,376 square meters and 808,990 square meters of spawning and summer rearing habitat, respectively. These barriers were prioritized based on proportion of potential passage improvement, annual adult equivalent production potential per square meter of habitat gain, species mobility, species condition, and a cost modifier. The unscreened water diversions were prioritized based on flow, species mobility, species condition and cost.
If the Olympic Wildlife Area and Region 6 Access Areas are an indication of the problems with fish passage structures and unscreened water diversions that exist on Department of Fish and Wildlife owned or managed land, there are many corrections that need to be made on the wildlife and access areas. For example, with the Olympic Wildlife Area and Rigion 6 Access Areas combined, 42% (25 of 60) of the culvert crossings, 100% of the dams (1) and 100% of the lake screen structures (1) are barriers to fish passage. Although 100% of the water diversions (2) are screened, it is doubtful there is a water right. To compliment the state salmonid recovery effort, the problem features should be corrected as soon as possible.