By: Metal Culverts, Inc
To say water is important to the state of Wisconsin would be an understatement. With over 15,000 lakes in direct proximity to Lakes Michigan and Superior (two of the 
largest sources of freshwater in the world), and 32,000 miles of streams, Wisconsinites prize their quality water resources. They utilize these resources for drinking water, recreational opportunities, crop irrigation, and as the base of a huge tourism industry. To ensure the quality of these vitally important water resources, managing runoff and stormwater have become a key focus of many municipalities and state environmental agencies as they must comply with strict stormwater management regulations put in place to help reduce the effects of urban expansion.
Plymouth Foam, a designer and manufacturer of foam products for the construction, packaging, display, and OEM markets recently decided to construct an addition at their Plymouth, WI facility. With the changes, Plymouth foam was required to develop a new stormwater management plan to help mitigate the effects of increased runoff that would occur from the expansion. Additional acreage for an above ground detention basin was unavailable at this project site, leaving an underground system as the most economical solution. A unique challenge that designers faced at this particular project site was the presence of an unusually high water table. This factor prevented the use of any type of perforated retention system, and led designers to select an underground corrugated metal detention system consisting of 1,242 lineal feet of 96” 14 gauge Aluminized Type 2 material fabricated by Metal Culverts Inc. and installed by Wagner Excavating of Sheboygan, Wi. The structure provided nearly 62,500 cubic feet of water storage. By utilizing below ground storage, the system was able to be designed large enough to allow for 2-3 feet of permanent water storage at the bottom of the pipe for total suspended solids removal.
To add an additional set of obstacles at this site, crews from Wagner were forced to work around incoming and outgoing truck traffic servicing the existing facility. According to Wagner project manager Josh Salm, the installation went quickly and was completed in a timely fashion without any real disturbances to the flow of truck traffic. The presence of working truck traffic 
also left little space for storage of the unconstructed system. Wagner worked closely with Metal Culverts Inc. to develop a delivery schedule that avoided “overloading” the busy jobsite and ensured the necessary components were on site and on time.
CSP once again provided the solution for a detention system that was cost effective, versatile, and completely customizable. By using a CSP system in this situation, the engineer was able to develop a structure that met the demands of the owner and all code requirements of the city and state.