Mar 02, 2009

Effectively Addressing Water Quantity & Quality

Integrated storm water management technologies have been implemented for a U.S. Green Building Council Leadership in Energy and Environmental Design-inspired corporate headquarters building in Chattanooga, Tenn.

The application of this sustainable approach to storm water management addresses environmental health, efficient land use and return on investment when compared to traditional storm water management plans. Constructed in 2008, the two-story 12,500-sq-ft office and warehouse building is located on 1.2 acres within a small industrial/office park where conventional public domain storm water management practices are employed. The technologies implemented at this site serve to reduce pollution from storm water runoff, limit the disruption to the natural site hydrology by reducing impervious cover, increase infiltration and allow for the reuse of water to reduce potable water demand from the local aquifer.

How It Works

The process begins with the collection of both storm water and roof runoff into a junction manhole. From there, water is plumbed to an underground Aqua-Filter water quality treatment train device manufactured by AquaShield Inc. The Aqua-Filter is designed to remove sediment, floating debris, oils, heavy metals (as particulate) and microorganisms using Pathex filter media by AS Filtration.

Water conservation is achieved through the use of an underground modular polypropylene storage unit. Rather than relying on water purified from a local aquifer for irrigation and toilets, harvested rainwater can now be used. Harvested rainwater reduces stress to the local aquifer and provides for a sustainable reduction in potable water use.

Maximizing Land Use

The traditional approach to storm water management included the use of an open detention pond. While detention ponds are well documented for their water quality and quantity benefits, their installation occupies land that could be used for other purposes. If this approach were followed, 11 percent of the available land use area would have been lost and plans for the future facility would be reduced by one half of the projected size.

Land use area was increased to 100 percent by using the underground water storage system instead of the detention pond. Through the use of the integrated technologies, a larger future commercial facility (3,250 sq ft) could be constructed and additional parking spaces could be located in place of the detention pond. This increase in building size correlates directly with an increase in rental area. With additional rental revenue each month, the additional cost of installing the underground storage tank was projected to be recovered in a year or less.

Project Benefits

The incorporation of the water quality and water quantity technologies into this sustainable integrated use system required advanced design planning and a larger investment compared to traditional water management practices. However, the benefits of their implementation can be realized in terms of additional revenue and a significant reduction in aquifer dependence. This investment was not only a cost-effective approach, but also a more environmentally friendly approach.