Our clients facility is exploring avenues to improve the site to comply with this credit, but is in a dense urban area (Oakland, Ca) and the landscaping on the site itself can not undertake any further improvement.
It is a small area (550 SF), planted optimally, using rainwater storage for irrigation, pervious pavers, etc. so the only other option we see available here is to expand the vegetation to the roof, or perhaps vertically along the walls. The roof area could be used for public space once vegetated, thereby complying with the intent of the credit, but there is no mention of this in the latest iteration of the reference guide.
My question is this: Does the expansion of additional vegetation on the roof and the installation of container plants qualify as site improvement? or is the credit more about the development of the plan itself than the actual recommended measures and eventual implementation?
This inquiry has been issues via Yammer as well, so I will repost a response once received on either platform.
Levi Jimenez
Founder & Senior ConsultantViable LLC
12 thumbs up
August 11, 2014 - 5:31 pm
GBCI Response 4/21/2014:
The project team is correct that this credit (specifically, "best replicate natural site hydrology processes") goes far beyond simply capturing water for reuse. And the site's hardscapes can be retrofitted to include modular vegetated areas (green roof, for example), porous paving, vertical landscaping, etc. However, as stated in the Step-By-Step section of the Reference Guide, "The GI or LID measures must be in place by the end of the performance period to satisfy the credit requirements." It's also important to note that v4 does not allow the required volume of water to be discharged offsite. The requirements mean that the project must manage (keep on site- through infiltration into the ground, evapotranspiration, and/or capture and reuse) all calculated runoff for 25% of the impervious areas, for the 95th percentile storm event.