Ten Mile Creek is a lowland tributary to the Nooksack River within WRIA 1, and drains an area of roughly 35.5 sq miles, with nearly 46 linear miles of stream length within the basin. Its headwaters issue from low elevation glacial till and trend northwesterly through a system of peat bog marshes. These then feed mainstem Ten Mile Creek and its tributaries, which flow westward across glacial outwash plains until making a confluence with the Nooksack River. Substrate is largely sand or peat with patches of gravel in the lower watershed, providing excellent rearing, and gravel and sand in the headwaters, which provide spawning. Species utilization in the system includes coho, chinook, steelhead, and searun cutthroat. The existing barrier located on Ten Mile Cr is a 0.9 diameter CST pipe encased in concrete and has a 1.6% slope. The culverts span is roughly 50% of the channels bed width. The pipe is a barrier according to WDFWs Level A assessment, and is a velocity barrier during high winter discharges, coincident to when overwintering juvenile are seeking refuge habitat. The proposed repair is the removal of the existing pipe and concrete, and the installation of a 40 X 15 prefabricated bridge with abutments outside of the ordinary high water mark of Ten Mile Creek. This improvement will provide access to 1.02 miles of upstream habitat, including 2100 sq meters of spawning and 2350 sq meters of rearing habitat.
