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 project site is 60 acres with major components including a hospital campus, parking garages, central utility plant and requisite parking lots and access roadways. We are applying LEED NC Version v2.2. There are 6 outfall points where stormwater leaves the 60 acre site - these are identified as outfall points 1, 2, 3, 4, 5, and 6. Outfall points 1 and 6 discharge into existing drainage channel \'A\'; outfall points 2 and 4 discharge into existing drainage channel \'B\'; outfall point 5 discharges into existing drainage channel \'C\'; and, outfall point 3 discharges into an existing storm sewer system. Existing drainage channels \'A\' and \'B\' are inadequate for capacity and velocity and reflect erosion. Channels \'A\' and \'B\' have been redesigned using Natural Channel Design techniques to provide structurally stable and aesthetically pleasing stream restoration corridors. No stream restoration is proposed downstream of outfall points 3 and 5. The existing imperviousness of the 60 acre site (i.e. current project LEED site boundary) is less than 50%. In our opinion, SSc61 credit compliance cannot be demonstrated under Option 1a (Discharge Rate and Quantity)for outfall points 1 and 6; or outfall points 2 and 4 but can be demonstrated under Option 1b (Stream Channel Protection) whereby the aforementioned stream restoration projects are proposed for existing drainage channels \'A\' and \'B\'. This leaves outfall points 3 and 5. It is our opinion that SSc61 credit compliance can be demonstrated under Option 1a (Discharge Rate and Quantity) for outfall points 3 and 5. Questions 1. The LEED-NC 2.2 submittal template for SSc6.1 is set up to receive Option 1a OR Option 1b. How is the submittal template filled out if certain outfall points from the LEED site boundary comply with Option 1a while the others comply with Option 1b as described in our case here? 2. Under Option 1A of the submittal template for SSc6.1, is the pre/post site runoff rate/quantity filled out based on the 1-yr 24-hr storm or the 2-yr 24-hr storm? The reference guide says to compute both the 1-yr and 2-yr storms but the template only provides room for one storm. 3. Currently we are reflecting 60 acres as our LEED site boundary. This area does not include the aforementioned stream restoration projects proposed for channels \'A\' and \'B\'. Does the 60 acre LEED site boundary have to include the adjacent stream restoration project areas? We are not proposing any new impervious surface in the stream restoration project areas. Are there any potential implications to adding or removing the stream restoration project areas from our current 60 acre LEED site boundary that could impact our LEED approach for this project? 4. What is the likely outcome of obtaining credit SSc6.1 for this project based on this CIR? 5. What additional information would be required to demonstrate SSc6.1 compliance for this project?