Combined sewer outfall replacement on 24th Ave NW begins Oct. 20
Seattle Public Utilities continues to asses stormwater runoff in Ballard.
Starting on Oct. 20 SPU will be replacing one of the combined sewage overflow pipes located west of the wooden pier at the end of 24th Avenue Northwest (NPDES 150).
The old pipe was constructed in the 1930’s and is one of the few outfall pipes that carry stormwater into Salmon Bay. A major problem is when it rains more than a tenth of an inch, stormwater mixes with raw sewage, overwhelming Ballard’s combined sewage system. 10 percent of the mix that spews into the Bay is raw sewage.
Project Manager Jerry Waldron shared details on the project.
“The Combined Sewer Overflow (CSO) Pipe, known as CSO Outfall 150, was installed in 1935 underneath the pedestrian pier at the dead end of 24th Avenue Northwest. It is a 30” wood-stave pipe that has deteriorated over time and its purpose is to release sewer overflows during heavy rain.”