Tillman Creek Mitigation

Location: Cle Elum, WA
Client: Bonneville Power Administration (BPA)

Several years after the Yakama Nation Fish Hatchery was built, BPA discovered a well supplying water for hatchery operations was lowering water levels in a nearby wetland. Otak was hired to design a riparian floodplain wetland to provide compensatory mitigation along Tillman Creek. Otak also prepared regulatory permits for ESA compliance, Army Corps of Engineers Nationwide and Ecology wetland permits and Hydraulic Project Approval. Construction oversight included directing contractors in grading, surveying, planting and irrigation. Otak currently monitors the site; as of the end of year three, the wetland is meeting performance standards.