Figure 3: To meet the project’s storage requirement, the staff designed a two-tier retention system, which minimized the required footprint and featured tiers running in opposite directions to ensure the system’s structural integrity.
Click here to enlarge imageThe second site – the medical center – is located on 46th Street on a two-acre plot and includes an 11,560-square-foot Audiology Center and a 13,840-square-foot future building pad. To address the clinic’s storage requirements of 30,000 cu. ft., CULTEC designed a retention system using the Recharger V8 chamber, currently the company’s largest-capacity stormwater chamber, providing in excess of 50,000 cu. ft. of storage. More than 450 Recharger V8 units and 3,200 tons of backfill stone were required for a half-acre, single-tier bed.
Design Considerations
In order to calculate each of the two systems’ configurations, the units’ parameters, along with the sites’ workable depths, desired bed areas, and required storage volumes were considered, as well as the fact that the systems would be used for retention. CULTEC also incorporated the storage of the backfill stone porosity at 40%, six-inch stone foundation depths, and typical six-inch chamber spacings. As a result, the company was able to provide the developer with proposed bed layouts, excavation volumes, minimum bed depths and the amount of stone that would be required for each of the installations.
At the VA clinics, the systems collect stormwater runoff in catch basins from each system’s basin inlet structure. The runoff then enters each of the Recharger V8 and 280 HD internal manifold systems and is conveyed throughout the bed of stormwater chambers. The internal manifold, unique to the these chambers, is composed of two side portals located on each chamber and the insertion of High-Volume Low-Velocity (HVLV) Feed Connectors. This feature provides design flexibility, decreases the required installation footprint, and eliminates the need for costly on-site fabricated pipe manifolds.
The underground systems capture, retain and treat large amounts of stormwater runoff in a relatively small footprint, proving to be an ideal solution to land constraint challenges and Federal and state requirements. Employing this system also freed up land that was ultimately used for other valuable purposes at each site.
About the Author:
Michael Nowak is a Field Sales Representative Specialist for CULTEC, Inc.