Because the infrastructure of southwest Sioux Falls, N.D., was at least 50 years old and was installed prior to modern standards, frequent flooding during rain events had become commonplace. The city sought to address this by investing in a $10.9 million storm drainage project that included replacing water mains, storm sewers, and road surfaces designed to keep neighborhood homes dry when heavy rains fall.
A study was conducted five years prior to determine the best method to correct the problem of flooding in the area. The study determined the city needed roughly 5.5 million gal of storm water storage. Typically, the city would install a detention pond, but this installation required a large amount of open land. In addition, there was a park in the neighborhood where a pond could be built, but the city did not want to take the park away from local residents.
The solution was to store the water underground with a Contech corrugated metal pipe detention system and rebuild the park on top. Given the size of the system at 222 ft by 461.5 ft, or roughly 1 mile in total linear feet of pipe, the pipe distributor for the project, Core & Main, reached out to Contech for available options to reduce installation time, delivery charges and overall costs. Contech suggested the Mobile Pipe mill, a mobile production vehicle that pro- vides fast and cost-effective onsite steel pipe manufacturing. Mobile Pipe is designed to be a self-supporting factory that can be quickly deployed and added to production. Once onsite, pipe manufacturing progresses quickly enough to allow pipe installation within four hours. This pipe meets the high levels of quality construction with high coil feed-rate speeds and the same lock-seam edge process used in conventional pipe manufacturing.
Utilizing the mill, more than 5,000 ln ft of 138- in. diameter ALT2 perforated CMP was manufactured onsite. The system includes a double header and 12 rows of pipe. A 108-in. bulkhead was placed on the west end and a 96-in. bulkhead on the east end. The system provides 740,519 cu ft of storage. The land above was reconstructed as a park that has soccer fields, green space, a paved walking loop and new playground equipment. This was the second and largest underground storm water facility in Sioux Falls.