Tillamook County and Port of Tillamook Bay
Tillamook County, Oregon
Flood Hazard Assessment and Risk Management
Tillamook County and Port of Tillamook Bay
Tillamook County, Oregon
Flood Hazard Assessment and Risk Management
The Southern Flow Corridor project is located at the confluence of three rivers in Tillamook County, Oregon. Tidal influence, extensive levee and slough systems, land subsidence, and high sediment loads create an environment with complex and chronic flooding patterns. NHC was selected by Tillamook Oregon Solutions, a locally driven, state supported stakeholder group, to develop alternatives to reduce flooding. Following a series of stakeholder meetings, a preferred alternative was selected, which reduces flood levels up to one and a half feet on Highway 101 through a wide range of floods. NHC prepared a benefit-cost analysis that was used to successfully obtain $3.5 million from FEMA. NHC led a consultant team through final design and construction management services for the project, which was completed in 2017. The project included the removal of over 40,000 feet of existing levee, construction of 9,000 feet of new setback levee, new flood drainage structures, removal and containment of contaminated soils, and about 500 acres of tidal habitat restoration. The project received a Grand Award in the ACEC Oregon’s 2018 Engineering Excellence Awards.