Coquille River Slough Slope Repair
A slope supporting a NW Natural gas line on the Coquille River (South Coquille, Oregon) has been slowly eroding away over the years. This winter the slope failure approached within a few feet of the gas line and an emergency stabilization was initiated by the Coos County Road Department. The gas line is embedded into soft over-bank deposits, located about 16 feet above the river. There is a 30-foot deep hole in the river bed adjacent to the failure results in an over 40-foot high failing slope. A cantilever type sheet pile wall was designed and constructed to support the slope based on our observations and experience with soft river deposits. The river bank and gas line was successfully stabilized along an approximate 200-foot long section using 40-foot long sheets.
