ABSTRACT
Watershed analysis is a tool to evaluate the condition of the resources and processes of a watershed. This chapter describes the use of watershed analysis to plan and evaluate aquatic habitat restoration projects in Wolf Creek, a low-gradient tributary of the Siuslaw River, western Oregon. Its runs of coho salmon Oncorynchus kisutch, chinook salmon O. tschawytscha, and steelhead O. mykiss have declined over 90% from historic levels. The watershed analysis for Wolf Creek was prepared by the Eugene District of the Bureau of Land Management using inventory information, historic data, and remote sensing. Wolf Creek is a naturally sediment-rich and rock-poor basin. Landslide and road impacts vary across the basin. Historic salmonid habitat depended on the presence of large woody material. Loss of instream woody structure from timber harvest and settlement beginning in the 1800s contributed to the loss of salmonid spawning and rearing habitat and increased water temperatures. Over the past 28 years the Eugene District of the Bureau of Land Management has completed extensive habitat restoration that includes placing in-channel structures in more than 19 km of third- to sixth-order streams, closing roads, removing or replacing culverts, placing rock and gravel into the channel, and increasing the percentage of conifers in riparian areas. Additional work has been performed on private lands through cooperation of the landowners and the Oregon Department of Fish and Wildlife. Monitoring includes spawning counts, snorkeling, smolt trapping, vegetation plot analysis, and photographic documentation of channel changes. Evaluation of restoration projects, particularly following flooding in 1996, indicated the aquatic system was responding to the restoration efforts as anticipated and shows positive responses. Although initial results are promising, additional monitoring is needed to determine the full impact of restoration efforts at the stream reach and watershed level.
