This project completes a design plan to restore tidal connectivity between South Deer Island Slough and the Columbia River by modifying the tide gate at the slough entrance. The 4,500 acre Deer Island complex, located at Columbia River mile 78 - 81 along the south (Oregon) shore of the lower Columbia River, historically consisted of tidally influenced backwater and slough habitats. The island is now mostly enclosed by dikes and is separated from the mainland floodplain by Deer Island Slough, a six-mile backwater channel. Water levels within the slough are regulated by tide gates at its northern and southern ends. In addition, an earthen berm was constructed at about the midpoint of the Slough separating it into disconnected northern and southern portions. Tide Creek is a 16-mile long tributary draining into the Deer Island complex from the west, which has been diverted from its historical channel into a constructed channel. Future restoration actions in Tide Creek also are included.
Deer Island Slough South Tidegate Retrofit
Restoration Project Type:
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