Columbia Bottomlands Restoration Multnomah County, Oregon

The restoration of 88-acres of wetland on the Columbia River near Scappoose is aimed at reversing the impacts of agricultural activity. Hydrologic and hydraulic analysis would inform the restoration of habitat for endangered salmonids, as well as the creation of a wetland mitigation site. In leading the design, geomorphology, and surveying, the Otak team also provided support on coordination with landowners and other key stakeholders.

A Habitat Restoration Design to Improve Wetlands and Fish Conditions

Despite site accessibility limitations for surface and groundwater monitoring, by using modified schedules during low tide the team kept monitoring on track while informing the restoration design. In accounting for these limitations, drone surveying was utilized to capture water level change over time across the expansive floodplain area. The effort includes a complex hydrologic regime caused by riverine tributaries like Scappoose Creek and Teal Creek, including tidal backwater conditions and flood flows from the Columbia River. With the potential to support juvenile rearing and adult off-channel refugia, the design would also restore habitat for 13 different populations of salmon and steelhead. Many regulatory agencies – including the Oregon Department of State Lands, U.S. Army Corps of Engineers, state and federal fish/wildlife agencies – as well as local jurisdictions required approval of the final design.