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My Locker

Detroit, Michigan

Owner:

My Locker

Engineer:

Nowak & Fraus Engineers

Contractor:

RBV Contracting

Installation:

November 2019

Technical Description:

  • 434' of 84" Perforated Aluminized Steel Type 2
  • Stormwater Management StormFilter®

To accommodate current and future growth, online custom clothing seller and manufacturer My Locker completed a $14 million build-out of a new 110,000-square-foot production and office facility in Detroit, Michigan. Previously spread across three properties, the company consolidated, expanded, and updated its building at 1300 Rosa Parks Boulevard.

On-site stormwater detention was required to meet the regulatory requirements of the City of Detroit. The regulations call for no increase in runoff volume for the 1 inch rainfall event and therefore the difference between “natural conditions” and proposed conditions runoff volumes cannot leave the site.

The site was tight, and other types of detention systems could not store the necessary volume within the proposed footprint. Thus, corrugated metal pipe (CMP) was the material of choice for underground infiltration. The 84-inch diameter system maximized storage volume, fit within the available footprint, and allowed for future access and maintenance.

Perforations within the detention system allow the system to “leach” into the underlying gravel and then infiltrate into the sub-grade. The perforations are placed in such a way as a majority of sediment is collected in the pipe and not the stone. This pattern is based on the hydraulics of the pipe and the required draw-down. The credit received from the infiltration system did not fully meet the requirements for the site as required by the Detroit Water and Sewerage Department (DWSD) Stormwater Credit Program but reduced the amount the owner had to “buy” (fee-in-lieu) from the City.

Water quality regulations call for the removal of 80% TSS of any water leaving the site following NJDEP requirements. This was achieved using a Peak Diversion Stormwater Management StormFilter placed downstream of the infiltration system. The StormFilter contains seventeen cartridges filled with Perlite to remove sediment, oil, and grease.

The project had been initially designed as a solid CMP detention system, and four pieces of solid wall pipe had already been shipped when the design change to perforated pipe was requested due to changing regulations. Contech quickly performed design calculations and worked with RBV Contractors to choose commercially available backfill materials to meet the new requirements. In addition, the remaining pipe had to be shipped in phases as there was limited site area available for installation activities.

Once the final design was completed and approved, installation took place over two weeks using excavators with straps to set the pipe, and gaskets and steel bands for the joints.  The site was back filled with a clean crushed aggregate and the entire system surrounded by a geotextile fabric.

“This was a tight construction schedule, and the design changes had the potential to impact the ability to open the new headquarters in a timely fashion,” said Jim Foucher, Vice President of RBV Contracting. “The Contech design team worked with multiple engineers and prepared various design details that would allow the system to be installed within the time-frame available. We are pleased with the effort that Contech assisted with the design and on-site support during installation. The project was successful from a schedule and overall budget aspect. We appreciate the efforts that Contech had with this project.”

Technical Description:

  • 434' of 84" Perforated Aluminized Steel Type 2
  • Stormwater Management StormFilter®

800-338-1122 | www.ContechES.com

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