At a Glance
Over 65 acres of important salmonid rearing habitat was restored by lowering the marsh plain surface, reconnecting surface flows between lakes, and restoring water flows.
Project Description
Like much of the Lower Columbia, Sauvie Island was altered as it was settled and developed. Important hydrologic and sedimentation processes were interrupted by the influence of the Columbia River dams, installation and maintenance of a flood control levee system, and hydraulic modifications made for agriculture such as earth berms and tide gates. Biohabitats joined the island restoration project to undertake the construction of the habitat restoration design.
At 26,000 acres, Sauvie Island is one of the largest river islands in the United States. Due to its location at the confluence of the Willamette and Columbia Rivers, Sauvie Island continues to provide important rearing habitat and food web exchange for out-migrating juvenile salmonids. The Sauvie Island project site is located in the North Unit of the Sauvie Island Wildlife Area. Owned and managed by the Oregon Department of Fish & Wildlife, it provides wildlife habitat as well as opportunities for hunting, fishing and recreational use. The wildlife area supports several species of salmonids including chum, Chinook, coho, steelhead and coastal cutthroat. Working in the Sauvie Island wildlife refuge is complicated by the remote project sites, the presence of sensitive threatened and endangered species, lake and wetland environments, and the diverse stakeholders that use the refuge for cattle ranching, hunting, fishing, and recreational river use.
CREST oversaw the design, permitting and implementation of restoration and enhancement actions that maximized the habitat potential of the wetland for juvenile salmon and other wetland-dependent species. Biohabitats was contracted to remove 3 artificial fish passage barriers and earthen berms, remove a dilapidated culvert, and install a refurbished rail car bridge, perform marsh plain lowering excavation, marsh and slough channel excavation, disposal and grading of excavated materials, overall site erosion and sediment control, BMP construction, and site seeding and revegetation services.
The project received the State Land Board's 2015 Wetland Project Award.