Repairs by the Metropolitan St. Louis Sewer District (MSD) to the force main sewer break in Chesterfield were completed this past Friday evening (September 12). Heavy rains and their impact delayed repair efforts earlier in the week.
The location of the break was just west of where Cordovan Commons Parkway turns into Howard Bend Station Road in Chesterfield, Missouri. The break was reported to MSD at approximately 5:00 AM on Monday, September 8. A temporary dam and pumping system were built at the site of the break to help prevent direct discharge to a drainage ditch that leads to the Missouri River.
To properly repair the force main, crews and contractors worked to fine solid, durable pipe on either side of the break – a 12-inch gash along the top of the force main. In essence, the section of damaged pipe had to be cut out of the force main and replaced with a section of new pipe. For the new pipe to properly take hold, it had to be connected to existing pipe that is not compromised or weakened in some way. Approximately 100 feet of 24-inch diameter iron pipe was replaced.
MSD crews completed clean-up efforts at the site of the break and other affected areas over the weekend.
A force main sewer is a sewer line through which wastewater is propelled by the force of pump stations located along the path of the sewer. Pump stations are sometimes necessary to overcome gravity and allow for the transport of wastewater to area treatment plants. Force mains are made of cast iron and can last anywhere from 25 to 50 years, depending upon the amount of flow the line handles and the corrosive properties of the wastewater.
The force main sewer in question was built in 1983 and a replacement is scheduled. Construction of the replacement force main is expected to start in 2016 at an estimated cost of $6.5 million.
The force main sewer break and associated manhole overflows have been reported to the Missouri Department of Natural Resources, as required by law. The total volume lost from the force main and associated manholes is being calculated and will also be reported the Missouri Department of Natural Resources, as required by law.