When planning began for a new, 47-acre shopping center in Milford, Conn., one of the many decisions to be made was how to manage storm water runoff on the site. The project's decision-makers were already familiar with Cultec, Inc.'s subsurface storm water infiltration system's design and benefits from work on previous projects. The company's plastic storm water chambers were specified for Clean Water Act compliance, but they also offered several other advantages along the way.
The Milford Crossing complex is anchored by Wal-Mart, with other large retailers, such as Bob's Stores, HomeGoods, Barnes & Noble and Starbucks, also on board. With an estimated completion date in early 2007, work began on the site in 2005.
When completed, the Milford Crossing shopping center will have nearly six acres of paved parking lots. Storm water discharges are generated by runoff from such impervious surfaces, as well as from building rooftops during snow and rainfall events. To prevent adversely affecting the local water quality, Clean Water Act Phase II regulations require that these impermeable surfaces
are counteracted by a storm water best management practice (BMP) that will prevent the runoff from polluting nearby water resources.
A BMP solution
The subsurface storm water retention/detention systems are one such BMP solution. A major benefit of these systems is the simultaneous pollution prevention and regeneration of natural waterways.
Cherry Hill Construction, Milford Crossing's excavation contractor, installed approximately 1,900 chambers to create four beds on the site. The Recharger 330 HD storm water chambers were chosen for their cost-effectiveness and ease of installation. The chambers' purpose was two-fold—first, to filter the runoff, and second, to store the storm water prior to it being infiltrated. Infiltration systems are one of the few means that provide significant groundwater recharge in areas with a high percentage of impervious surface area.
"The sheer size of the impervious surfaces created by both the parking lot and the buildings themselves has implications for the surrounding area," said Sebert Dotson, site manager from Cherry Hill Construction. "The shopping center is close to a tidal basin and the property is bordered by a river, so making sure these waterways did not become contaminated was our main concern."
With a design capacity of more than 400 gal, the Recharger 330 HD is one of the largest chambers available. It is designed to store large amounts of water while saving land space and offering design flexibility. The polyethylene chambers are durable, yet lightweight and can be installed by one or two workers, resulting in reduced labor costs and time.
"Those of us on site appreciated the quick and simple installation of the chambers," Dotson said. "The amount of area you can cover is tremendous, and you can get the job started and finished quickly. This kept our labor costs to a minimum."
As the rates of commercial development and land costs continue to rise, contractors, developers and engineers will continue to look for efficient and cost-effective approaches to managing storm water.
In cases such as Milford Crossing, subsurface infiltration systems can offer an environmentally sound alternative to traditional above-ground options while reducing the amount of time and money spent on the installation.