Rating System

LEED BD+C: New Construction, LEED BD+C: Core and Shell, LEED BD+C: Schools

Rating System Version

v3 - LEED 2009, v2 - Schools 2007, v2 - LEED 2.2, v2 - LEED 2.0

Inquiry

1. CREDIT ISSUE Our project is seeking clarification on LEED for New Construction Sustainable Sites Credit 6.1, Quantity Control. Our project treats and manages stormwater directly across the street from the project, using a stormwater management (SWM) pond. This pond was designed as a regional facility specifically to handle this site and other adjacent sites as part of a regional SWM plan. It was always the intention for this pond to handle quality and quantity control for this site. The question is whether or not our stormwater management measures, which are directly adjacent to the project, will qualify for this credit since they are off-site? 2. STRATEGY Our approach is to use the credit\'s Option 1, which requires "a plan to protect the receiving stream from excessive erosion by implementing a stream channel protection strategy and quantity control strategies." Using cross section analysis we can demonstrate that the receiving stream for the SWM pond has adequate capacity, it means that the 10 yr runoff is contained in the bed and banks of the stream. At the same time the cross section analysis will give us velocity for the 2 year runoff that should be equal or less than the allowed velocity for the ground cover of the stream that is specified by State law. 3. INTENT In addition to meeting the technical requirements, we also believe we meet the credit\'s intent, which is to "limit disruption of natural hydrology." By channeling stormwater to a detention and treatment pond we are protecting streams from peak discharge rates, thus maintaining natural hydrology. Furthermore, the design team has placed emphasis on maintaining vegetated open space on the project site. The project exceeds the local zoning\'s open space requirement by 92%, thus improving on-site infiltration and retaining natural functions of the site.