Credit language clearly indicates that wetlands and naturally designed ponds can count as long as their sides are vegetated and their gradient no more than 1:4. Are stormwater detention/retention basins considered a wetland? These areas are typically dry and vegetated and would promote biodiversity; but hold and percolate rain during events through an underground drain or some kind of overflow. Our position is that stormwater basins are not wetlands nor are they ponds. They are simply open space. Does anyone have a similar precedent or stance on this?
It wouldn't matter except that stormwater basins are typically drawn here in CA with a 1:3 slope side gradient...
Saurabh Shrestha
HKS Architecture4 thumbs up
April 6, 2016 - 10:03 pm
My two cents, if you are already defining an area as a 'detention/retention basin', then it might be a little difficult to call them 'open space'. But you might want to check with GBCI.
Landry Watson
Assistant Vice President - SustainabilityAlexandria Real Estate Equities
29 thumbs up
April 6, 2016 - 10:13 pm
Can you expand on why you believe it would be difficult for a basin to be open space? Directly from the credit language - Open Space is defined for the purposes of LEED calculations as the property area minus the development footprint; it must be vegetated and pervious. Stormwater basins are vegetated and pervious, and can promote biodiversity by providing habitat - just as well as any other landscape feature - I'd argue. But the credit language excludes wetlands and ponds if they have slopes greater than 1:4 - but doesn't really explain why. So...the question remains...if I have a grassy landscaped area that ironically has a 1:3 slope side...is it all of a sudden not capable of supporting habitat? I'm submitting those areas in my calculation and will update this thread after for anyone interested.
Saurabh Shrestha
HKS Architecture4 thumbs up
April 6, 2016 - 10:39 pm
What I was trying to convey is that if you call an area a detention basin, it would probably fall under the same category as wetlands and ponds. So the restriction on the slope might apply. But I see your argument why the restriction exists in the first place for wetlands and ponds. My guess is it's because the area would be closed and inaccessible, but I might be wrong since the definition of open space does not address accessibility. So I agree with you on that one. It would be great to see how it goes. Good luck!