Fish and habitat assessment of Stetattle Creek
Anthony H and Rawhouser A. 2014. Fish and habitat assessment of Stetattle Creek. Natural Resource Technical Report. NPS/NOCA/NRTR—2014/924. National Park Service. Fort Collins, Colorado
To restore lost power generation capacity at the Diablo Powerhouse, Seattle City Light has proposed excavating up to 19,500 cubic yards of material from the alluvial fan of Stetattle Creek. Stetattle Creek is the only tributary to Gorge Reservoir in which bull trout spawning has been documented and is the primary spawning stream for native rainbow trout. Disturbance or habitat alteration of this stream or its alluvial fan could negatively impact the rainbow trout population in addition to the federally threatened bull trout. To better understand the extent and nature of the potential impacts related to the Diablo Powerhouse Tailrace Project, National Park Service staff conducted a series of surveys in 2013 to assess fish use, spawning habitat, substrate structure, and the benthic macroinvertebrate communities in the lower 0.5 miles of Stetattle Creek and its alluvial fan. Snorkel surveys indicated that rainbow trout and native char were actively using the entire survey area including the area proposed to be excavated as part of the Tailrace Project. Observations of rainbow trout indicated that this population initiated spawning in early June and continued spawning through the end of July. The infrequent nature of native char observations made it difficult to determine the duration of the spawning season; however, it appears that adult fish were entering Stetattle Creek towards the end of September and continued spawning through the end of November. Data from benthic macroinvertebrate samples indicate that the alluvial fan is likely providing a good source of prey items for the Gorge Lake fish population.
- Type
- Published Report
- Authors
- Anthony, Hugh; Rawhouser, Ashley
- Date of Issue
- 2014-12
- Publisher
- National Park Service
- Units
- NOCA , NRSS , ROLA
- Keywords
- alluvial, benthic macroinvertebrate, Bull Trout, Diablo Dam, Diablo Powerhouse Tailrace Project, Dolly Varden, Dredging, Eastern brook trout, Fish, Fish Survey, Gorge Lake, Habitat, NOCA, Non-Native, North Cascades National Park, Rainbow Trout, Redd, Sediment, Spawning, Stetattle Creek, Substrate, Threatened
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Fishes