PADEP Approves Innovative Stormwater Management Technique for Village at Valley Forge

PADEP recently approved a stormwater management permit under which the developer may use an innovative stormwater best management practice: discharging treated stormwater to groundwater via an underground karst piping system.

At The Village at Valley Forge, a 152-acre mixed-use development project in Upper Merion Township, Montgomery County, the karst geology and the presence of sinkholes prevented conventional stormwater infiltration controls from being used across most of the site. F. X. Browne, Inc., in conjunction with KCF Groundwater, Inc. and NTH Consultants, Ltd., has designed an innovative system of vertical drains to convey runoff into the epikarst, reducing the volume of runoff leaving the site. Epikarst is the upper surface of karst (limestone or dolomite), consisting of a network of intersecting fissures and cavities that collect and transport water underground. The epikarst allows rapid infiltration and storage of water infiltrating down from the surface. F. X. Browne, Inc. has designed a series of water quality BMPs across the site to treat the runoff before it enters the vertical drain system. A monitoring plan has been developed to observe the quality and elevation of the groundwater upstream and downstream of the site.

In addition to discharging the stormwater underground, the Village at Valley Forge will use other best management practices around the development, such as wet ponds, forebays, infiltration beds, rain gardens/bioretention areas, Vortechs hydrodynamic separation units, vegetative filter swales and street sweeping. For more information visit http://www.depweb.state.pa.us/news/cwp/view.asp?a=3&q=527446 

For more information on innovative stormwater management BMPs or stormwater management in areas with karst geology, contact info@fxbrowne.com.