DESCRIPTION
The construction of U.S. 101 through Willapa Bay in the 1930s cut off several salmon-bearing streams from their natural terminuses in Willapa Bay and restricted tidal flows to hundreds of acres of tidal wetland on the Bay's shore. The terminus of South Creek, located at the southern end of Greenhead Slough, has been shifted from a probable historical location along Bear River to its current location at the northern end of Greenhead Slough. Greenhead Slough itself is disconnected from Bear River by a driveway levee running from U.S. 101 to a house now owned by WNWR. Tidal flows to the southern end of Greenhead Slough are restricted by an undersized culvert on a BPA access road near the southern end of Greenhead Slough. This project would: replace the undersized BPA culvert with a larger culvert that does not restrict fish access; add a connection (culvert or bridge) between Greenhead Slough and Bear River; reroute the end of South Creek into Bear River through the new Greenhead Slough/Bear River connection; and add LWD to South Creek to address recorded deficiencies in sediment quality and macroinvertebrate diversity.
The construction of State Route 101 through Willapa Bay in the 1930s restricted tidal flows to hundreds of acres of estuarine wetland on the eastern side of Willapa Bay, an area now called Greenhead Slough. Five streams that used to flow off Bear Ridge and into Willapa Bay now terminate in Greenhead Slough, which flows north in a ditch along SR 101 to the Slough's one bridge. The southern end of Greenhead Slough is separated from Bear River by a dike originally built for logging, now providing access from SR-101 to a house owned by Willapa National Wildlife Refuge. Tidal flows to the southern end of Greenhead Slough are restricted by the constricted path of the Slough ditch, which passes under the under-sized Greenhead Slough bridge and eventually through an undersized culvert on a BPA access road near the southern end of Greenhead Slough. The ditch is deeply incised and has downcut under the Greenhead Slough bridge. This project will evaluate and design actions to restore 86 acres of estuarine habitat in southern Greenhead Slough and increase connectivity between water bodies. Actions to be considered include a new bridge or culvert in the dike between Greenhead Slough and Bear River; a new bridge or culvert in SR 101 to connect South Creek/Greenhead Slough and Bear River, and restoration of historical tidal channels in southern Greenhead Slough. The project will increase area and function of estuarine habitat and provide additional off-channel habitat for fish.
