Underground Stormwater System Replaces Traditional Above-Ground Option

Edited By Steve Hudson | September 28, 2010

According to Georgia officials, the state's population is projected to grow approximately 20 percent between 1995 and 2025, reaching almost 2.7 million. As a result, the state has implemented a Greenspace Program that will help offset the damaging effects of this dramatic growth. The program covers a number of elements, including how to manage stormwater runoff and protect water resources.

Recently, to meet green space requirements, satisfy land constraints and replace outdated methods while planning for a residential development in the Buckhead area of Atlanta, engineers selected a CULTEC stormwater management system.

As in the case of commercial building, residential development requires that special attention is paid to the management of stormwater runoff created by the extensive areas of impervious surfaces such as roofs, cul-de-sacs and driveways.

Originally, the Pulte Homes' townhome community — "Overlook at Lenox Views" — was designed to include a deep pond with retaining walls in which stormwater runoff could be contained. But that option was not possible due to the Greenspace Program requirements, which encourage urban and rapidly growing counties to set aside 20 percent of their land as protected green space — land that can be used for informal recreation or natural resource protection. This meant the land required for the planned detention pond would have to be reclaimed and used for environmentally friendly purposes.

"When we learned about the green space regulations," said Ted McCarter, Southeast regional sales manager of CULTEC, Inc., "it was right back to the drawing board. Any above-ground option, such as a detention pond, was not feasible due to the amount of land it would occupy."

But an underground system would allow the acreage to do double duty.

"By placing the system underground," he said, "the site can effectively and efficiently manage stormwater, while the land above can serve as a play area or garden and fulfill the state's green space needs."

With the help of CULTEC experts, engineers from Travis Pruitt Associates, Inc. designed a three-tiered underground stormwater detention system that would capture, treat and temporarily store runoff until its subsequent release to a storm-drain, wetland or other off-site area. CULTEC, Inc., headquartered in Brookfield, Conn., manufactures plastic chambers used in subsurface retention/detention stormwater management systems and septic applications. In addition, CULTEC has designed its own manifold and water quality systems to complement its product line.

The system used on the Buckhead project consists of 604 chambers constructed of high-density polyethylene and is designed to maintain a significant amount of water. Such multilevel systems require deeper excavation but can be suitable solutions on projects such as this one, where land constraints must be kept in mind while allowing for adequate stormwater-handling capabilities.