Dec 08, 2014

Storm Water Detention & Sand Filter System Installed at Townhome Development in North Carolina

The 17,000 cu ft detention and filter system was installed to control and treat rainwater runoff

storm water detention, sand filter system, Cottages on Providence

Oldcastle Stormwater Solutions Group supplied a 17,000 cu ft storm water detention and sand filter system at the new Cottages on Providence development in Charlotte, N.C., an upscale townhome development by Wendy Field Consulting.

Site designer Orsborn Engineering Group of Charlotte, N.C., needed a combination storm water detention and sand filter system to control and remove pollutants from post-construction runoff for this dense urban development. Oldcastle Stormwater Solutions manufactured and delivered its Storm Capture module system to meet the requirements for an integrated storm water detention and treatment system with large storage capacity and a small installed footprint.

The storm water detention system, sand filter system and forebay chambers were combined to create a single storm water management system. The system, installed under the driveway between two rows of townhomes, includes a detention system comprising 19 5-ft-tall modules; a sand filter system, created using six 9-ft-tall modules; and two sedimentation forebay chambers, comprising two 9-ft-tall modules.

The forebay chambers trap large sediments and floatables, while the sand filter uses sand media to filter smaller particles and other pollutants. The detention chamber will store runoff and allow sufficient time for treatment through the sand filter. Discharge from the system is controlled by an orifice plate at the outlet pipe. The system is designed to meet AASHTO HS-20-44 for traffic loads and has multiple manways for future maintenance access. The storm water management system receives water from site storm drains and downspout collection pipes, as well as from a grate directly over the top of one of the forebay modules. Water will pass through the Storm Capture system and then out to the storm drains.

Charlotte, N.C.-based Siteworks LLC installed the system over a three-day period, in June 2014, for General Contractor HR Construction. The base sections of the sand filter, detention and forebay modules were installed the first day. On day two, the modular nature of the system provided the contractor with an opportunity to install all of the internal sand filter components (under drain piping, stone, and sand media) while the system was still open. Then, on day three, the tops of the modules were installed and backfilling operations began. 

The storm water management system constructed at The Cottages on Providence project will control and treat rainwater runoff during storms, adding a positive result to the communities’ environment now and in the future. The Cottages on Providence is scheduled to have townhomes available for occupancy in January 2015.