Rating System

LEED BD+C: New Construction, LEED O+M: Existing Buildings, LEED BD+C: Core and Shell, LEED BD+C: Schools

Rating System Version

v3 - LEED 2009, v3 - LEED 2008, v2 - Schools 2007, v2 - LEED 2.2

Inquiry

The intent of SSc6.2, interpreted from the manual and subsequent CIRs, is to minimize the disruption and pollution of natural water bodies by contaminated stormwater. To meet the Credit Intent, the Requirements specify active TSS treatment of stormwater, using BMPs that reduce the percentage of contaminants in the runoff. The project site is 5.24 acres and has 3 acres of impervious surfaces. The site is part of an overall 75 acre master plan that empties it\'s stormwater into Tributary A, North Buffalo Creek. There is an existing retention pond in the middle of the Park that is adjacent and just North of the Site (not located within the project site for LEED). The drainage area to the pond is +/- 44 acres of highly developed office and commercial property and 70% of this area is impervious. The project site is included within these 44 acres. The pond drain is an open pipe with headwall. The outlet pipe runs underground through the Site and empties upstream of the proposed building into Tributary A, North Buffalo Creek. The Site has an existing storm sewer outflow system designed and sized for future development of this site plus the upper buildings and parking lots (approximately 9 acres). This system empties directly into Buffalo Creek downstream of the proposed LEED building. We propose to modify the spillway of the existing pond to treat approximately 110,000 C.F. of stormwater for the extended acreage in lieu of treating stormwater only for the project site. Of the overall 75 acre master plan, +/- 44 acres runoff into the pond and contain untreated water, entering and exiting the pond without allowing pollutants and suspended solids to be removed. Given the existing stormwater system, it does not make sense to treat stormwater on the project site, but rather to treat all of the stormwater from the larger 44 acre site. We believe that treating the 44 acres will meet and exceed the intent of the credit for the following reasons: 1) We will create a new spillway with an orifice that stores the first inch of runoff for the entire 44 acres, which will achieve 85% TSS removal based on existing monitoring and will be constructed in accordance with the Greensboro Stormwater Design Manual. 2) The project site is part of a 75 acre master plan and by creating the spillway we will be maximizing the positive impact on the overall water quality entering Tributary A, North Buffalo Creek for an area that is 25 times the project site\'s size. The spillway will also resolve any associated stormwater system issues that were previously designed and constructed in a less environmentally friendly manner. We believe that we meet and exceed the intent of SSc6.2 because we are aiding in the overall water quality improvement and pollution minimization for the Buffalo Creek through stormwater quality control and therefore will earn this credit. Please confirm that achieving the treatment requirements for the larger 44 acre site will enable the project to earn the credit and perhaps be eligible for an exemplary performance ID credit. Also please confirm that we will be able to earn this credit by treating the Stormwater outside the project site as defined for the LEED submission.