For CREST on Sauvie Island near Portland, OR
This project restores floodplain habitat to three sites on Sauvie Island. These sites are currently disconnected from tidal influence except at very high flows which potentially traps fish. Much of the existing sites are dominated by reed canary grass. We worked with a multi-disciplinary team to provide geomorphic context, hydrology and hydraulic modeling, alternatives analysis and cost estimates for all three sites and are working on final design. In defining the chosen alternatives we incorporated local vegetation elevation relationships. We used geomorphic analysis to size tidal channel connections and emergent marsh tidal prisms. The feasibility of these projects are tied to funding for ecological goals for salmon habitat and provide additional water quality and habitat benefits for multiple birds, mammals, and aquatic species. Restoring fish habitat in a bird refuge requires additional attention and design detail to hydrologic regimes of the wetlands. Sauvie Island offers floodplain refuge habitat just downstream of the urban waterfront corridors on the Columbia and Willamette Rivers.