| Abstract/Description or Keywords |
The Walden Power forebay was operated throughout the freshet period with the radial gate in an undershot position. This allowed gravel moving downstream with the current to continue through the forebay and into the lower reaches of Cayoosh Creek. The forebay was drawn down on two occasions near the end of the descending hydro graph, July 04 and July 10, 2003, to encourage mobilization of settled gravel within the forebay. Re-mobilized gravel settled within the lower reaches of Cayoosh Creek where it could later be utilized as spawning gravel by both non-anadromous (resident) and anadromous species of fish. Following forebay gravel mobilization, three size classes of gravel (2.5, 5.0 and 7.5 cm diameter respectively) were each painted with a unique color per size class and placed within Cayoosh Creek. Locations chosen (sites 1-3) were downstream of the forebay and known to be previously utilized as spawning habitat by anadromous fish. These sites were monitored to determine hydrological movement patterns of the various sizes of gravel. All painted gravel remained where placed through ramping events, but was displaced during pink salmon spawning activity in September 2003. sediment, habitat, salmonid, aquatic habitat |
