Manistee Sanitary Sewer Improvements

The City of Manistee’s 6th Avenue pump station conveys all the sewage from the north half of the City’s sewer system, under the Manistee River, and ultimately to the City’s wastewater treatment plant. The pump station was constructed in the 1940’s and had very frequent clogging problems. The force main connected to this station was constructed in a hand-dug, 100-year-old tunnel beneath the river, and with no way to test the pipe, the integrity of the main was unknown. An interceptor sanitary sewer that fed the pump station was also aging and in danger of failing. As the Engineer of Record for the City of Manistee, Spicer Group analyzed the issues and designed a solution. It was identified that additional hydraulic capacity was required and a new, larger pump station with updated controls and metering capabilities was necessary. The original force main in the tunnel was abandoned, and a new pipe was directionally drilled approximately 915 feet under the river. The original failing interceptor pipe was replaced with 500 feet of 15-inch PVC gravity interceptor sewer that was protected with a 400-foot-long steel sheet pile sea wall meeting USACE standards. Spicer Group was responsible for the study, permitting, preliminary design, final design, bidding, construction inspection, testing, and construction administration services for the project. Due to the work being performed within the Manistee shipping channel, close coordination with EGLE, US Army Corps of Engineers, Manistee County, the City of Manistee, and the US Coast Guard was required.