Hood Canal Estuary Restoration at Cattail Lake Kitsap County, Washington

After more than 60 years artificially isolated from tidal influences, the opportunity to restore Cattail Lake was initiated as part of mitigation for construction at nearby Naval Base Kitsap. A new bridge, selective revegetation and complete permitting strategy are features of this mitigation plan to restore intertidal functions.

A Bridge Design and Mitigation Plan for Estuary Restoration

Restoration of the estuary off the Kitsap Peninsula in northwest Washington included the eight-acre, freshwater Cattail Lake that had been impounded on Hood Canal. The design reestablishes intertidal, riparian, and upland habitats with selective revegetation while a new bridge replaces two under-sized culverts to provide anadromous fish access to the watershed. Hydraulic analysis  determined the new stream channel width as well as its scour potential. That analysis informed the single span bridge design, from its 100-foot length to the recommended riprap and deep foundations installed as scour countermeasures. Through research and design, Otak led this project while also playing a key role in coordinating with the Army Corps of Engineers, National Marine Fisheries and US Fish and Wildlife Services, Washington State Department of Ecology, and Washington Department of Fish and Wildlife for necessary permitting.