Chahalpam Crossing

This project reconnected the North Santiam River to Dieckman Creek on the Chahalpam Wildlife Area to restore floodplain function through 1) enhancing in-channel connection to improve fish passage, flow and hydrology while reducing conditions that favor invasive species; and 2) restoring the ecological function of historic habitat to increase the complexity necessary for fish and wildlife. The Chahalpam Crossing project replaced undersized culverts that limited fish passage and restored riparian habitat adjacent to the crossing. Actions included removing invasive species, developing an engineered design to replace the existing structure with a bridge, seeking Sections 7 and 106 compliance, securing a contractor to implement actions, implementing construction, and replanting floodplain forest vegetation. This project initiated floodplain connectivity on Chahalpam by implementing one of the projects identified in a floodplain restoration analysis developed by the River Design Group. Key project partners included the North Santiam Watershed Council, Marion County Soil and Water Conservation District, Oregon Department of Fish and Wildlife, Oregon Department of Transportation, United States Fish and Wildlife Service, and OWEB.

Historically, the North Santiam River was comprised of vast floodplain forests in this reach, with multiple dynamic side channels and significant runs of Upper Willamette spring Chinook salmon and winter steelhead. Both of these salmonids are listed as threatened under the Endangered Species Act and the North Santiam River remains a key basin for their recovery. However, current habitat conditions are significantly lacking. While these fish species have been observed in the floodplain habitats of the Lower North Santiam River, quality habitat is limited due to channel simplification, installation and maintenance of flood and channel migration control structures, and conversion of floodplain forests to agricultural fields.

This project will contribute to Chinook salmon and winter steelhead recovery efforts by restoring access to historic habitat. Reconnecting the North Santiam River to Dieckman Creek by replacing the fish passage barrier will increase flows and link adult and juvenile salmonids to historic side channel habitat that is inaccessible during times of the year. Removing this barrier will increase adult salmon and steelhead access to cold water refugia during the summer months and juveniles will have increased access to refugia and rearing habitat.