In 2008, Contech Engineered Solutions was contacted by Kearney Construction regarding a project they were bidding that proposed a large underground detention system to address the site’s stormwater management needs. Kearney
had experience working with Contech, so they asked our engineers to review the design and develop a more cost-effective solution.
The original stormwater management design included two large underground detention systems. The specified systems were a proprietary
modular concrete system designed to provide the 101,518 cubic feet of storage needed to meet the site’s water quality and peak rate attenuation requirements. As Contech engineers reviewed the original design, multiple challenges were identified.
The original system occupied the majority of the site’s open space and therefore offered little potential for expanding the system’s footprint. Groundwater levels were elevated, limiting the storage depth, and the already tight site included multiple utility conflicts. Understanding these
design challenges proved essential to presenting a comprehensive solution and ultimately contributed to the success of the Contech solution.
Contech has a variety of underground storage solutions in its Stormwater portfolio. These solutions include modular concrete systems, corrugated metal pipe solutions, and a plastic chamber solution. After considering the project specifics, corrugated metal pipe was identified as the most cost-effective solution for this project and consisted of
approximately 5,115 feet of 60” diameter corrugated metal pipe. Similar to the original design, this solution consisted of two systems providing 101,630 cubic feet of storage. The system also included two integrated outlet control structures to discharge the necessary water quality and peak rate attenuation volumes. To collect surface runoff along the rear service drive, Contech’s slotted drain was installed in the flow-line of the Type “F” curb. This eliminated the longitudinal sloping, resulting in simplified grading and improved aesthetics.
Once the design was complete and all necessary submittals approved, the system’s fabrication was initiated at Contech’s plant in Pinellas Park, Florida. Contech representatives coordinated regularly with Kearny Construction to ensure their material needs were understood and delivery schedules met. Additionally, Contech engineers visited the project site at the beginning of the installation process and many times throughout the system construction to provide guidance and observe the installation process.
Kearney looked to Contech for a more cost-effective solution and Contech delivered. The installed CMP detention system reduced the owner’s investment in the site’s underground detention system by approximately 45 percent, representing a win for all involved in this value-engineering effort.