DESCRIPTION
This project is located on the right bank of the Lower White River in the City of Pacific, between River Mile 5.5 and 6.3. The project will reduce flood risk in a way which restores habitat and habitat forming processes. The project will remove over 4,100 linear feet of existing revetment and other artificial fill, reconnect the river to a broader portion of its floodplain, build a setback levee to limit the bounds of flood and erosion hazards in this reach, and improve the riparian buffer and wetlands. Initial acquisition of private properties to implement the setback levee project began in 2009 and will continue concurrently through the project design phases. Acquired properties are being converted to and maintained as open space until the final project can be implemented. King County Flood Contol District expenditures on this project to date are $4,915,522. Construction is currently planned to be phased, beginning in 2015 and being completed in 2017.
This project is located on the right bank of the White River between RM 5.5-6.3.
Currently, off-channel habitat in the lower White River is limited and the floodplain is mostly armored and/or at risk for further development (Kerwin 1999). Levee construction, channel straightening, dredging and gravel scalping, bank armoring and removal of large wood from the active channel have had a major effect on the geomorphic and biological features of the White River (WDFW et al 1996). In the lower 12 miles of the White River, features such as bank cover, pools, side channels, and overhanging vegetation are practically nonexistent (WDFW et al 19996). Within the lower river, this project has potential to allow interaction with riparian vegetation for channel shading and large wood recruitment, as well as increase off-channel rearing habitat and flood refuge for native salmonids, particularly Chinook.
The active river channel is disconnected from its floodplain by a levee and revetment facility and artificial fill resulting in constriction of the main channel and the loss of access to side-channel habitat for flood refuge and rearing habitat. Landward of the levee is a wetland and side channels that have been cut off from the river.
All 5 species of Pacific salmon, steelhead, and bull trout occur in the project reach (Kerwin 1999). Within the lower river, this project has potential to increase off-channel habitats, interaction with riparian vegetation to recruit large wood, create side channels that can be used for rearing and flood refuge by native salmonids, particularly ESA-listed Chinook.
This project will remove over 4,100 linear feet of existing revetment and artificial fill, reconnect the river to its historic floodplain, build a setback levee to limit the bounds of flood and erosion hazards in this reach, and improve the riparian buffer and wetlands. Initial acquisition of private properties to implement the setback levee project began in 2009 and will continue concurrently throughout the project design phases. Acquired properties are being converted to and maintained as open space until the final project can be implemented. Construction is currently planned to be phased, beginning in 2015 and being completed in 2017.
