Mox Chehalis Route 8

These three barriers are on tributaries to Mox Chehalis Creek which flows into the Chehalis River. Correction of these three barriers improved access to 1.29 miles of habitat for coho, cutthroat and steelhead. Site B is on a small stream with 0.22 miles of habitat gain. Site A and C have 1.07 miles of habitat gain (C is upstream of A). Site A was a puncheon removal which was replaced by a 12 ft. wide pipe arch culvert with an 8 ft. rise. The pipe is 40 ft. long and installed using the WDFW stream simulation method. The slope through the project site for the stream is 1.7%. Site B is a small stream with a 2 ft. diameter culvert elevated roughly 2 ft. at the downstream end. The replacement was a 6 ft. round pipe 40 feet long, installed using the stream simulation method with a stream slope of roughly 4%. Site C was a puncheon removal with no culvert or crossing being replaced. This allowed the 4 ft. bank full width tributary to flow freely through this old crossing.


Posted on

February 25, 2020