DESCRIPTION
The primary objective of the Prairie Creek Barrier Removal is to replace an existing fish passage barrier with a fish passable structure. The goal of this action is to construct a culvert that will restore salmon access to 4.75 linear miles of potential habitat; approximately 260 square meters (0.06 acres) of spawning habitat and 10,172 square meters (2.51 acres) of rearing habitat for the Southwest Washington evolutionary significant unit (ESU) of coho salmon, and the Southwest Washington distinct population segment (DPS) of winter steelhead trout, as well as searun cutthroat and resident cutthroat trout.
The culvert proposed for replacement is ranked 14th on a list of priority culverts for replacement within the Chehalis Basin and 8th on a list pf priority to be replaced that are owned by Lewis County. A stream survey on Prairie Creek was performed by the Lewis County Conservation District in 2001. A priority index (PI) of 16.22 has been assigned to this barrier culvert.
The project replaced an existing 10 ft x 5 ft box culvert, 56 ft in length, which was 0 percent passable due to a slope of 1.4 percent slope and lack of substrate in the culvert, with a 18 ft wide by 10 ft tall box culvert; approximately 84 feet in length. In addition to placement of the fish passable structure the stream channel was regraded within the area 75 ft upstream and 65 ft downstream of the new structure. A pool was excavated within the channel and a large woody debris structure was placed downstream. Approximately, seven bigleaf maple, six western red cedar, and 76 Geyer willows were planted within the riparian buffer. Channel banks were also hydroseeded with a native mix consisting of various grasses, Nootka rose, common snowberry, Oregon grape, and oceanspray.
The replacement of this culvert has restored access to 4.75 linear miles of potential habitat; approximately 260 square meters (0.06 acres) of spawning habitat and 10,172 square meters (2.51 acres of rearing habitat for the Southwest Washignton evolutionary significant unit (ESU) of coho salmon, and the southwest Washington evolutionary significant unit (ESU) of coho salmon, and the southwest Washington distinct population segment (DPS) of winter steelhead trout, as well as searun and cutthroat trout.
Since this culvert has been replace the adjacent landowner has reported seeing salmon in the large woody debris.
