Can anyone tell me how LEED is defining "in a manner best replicating natural site hydrology processes using low impact development and green infrastructure?" In an earlier version it was defined as a "soil and vegetation-based approach." If that is still so, is there a way to achieve the credit in zero lot line buildings in an area such as Manhattan where there is virtually no soil or vegetation or in Miami where the water table is so high it is impossible to infiltrate?
You rely on LEEDuser. Can we rely on you?
LEEDuser is supported by our premium members, not by advertisers.
Go premium for
Theresa Backhus
Sites Technical Specialist, LEEDUSGBC
66 thumbs up
December 7, 2012 - 3:59 pm
Hi Pamela,
It is defined the same way as in the previous versions; the definitions have just moved to the online Glossary (while viewing each credit, you can "toggle" the glossary on or off). You can also view the full Glossary here:
https://new.usgbc.org/glossary
A path was actually created specifically for zero lot line projects in urban areas (3 points). The percentile of rain events threshold was lowered to the 85th percentile. The definition you mention above is for "green infrastructure," but projects can also use other engineered practices such as rainwater harvesting.
The v4 Rainwater Management credit language can be found here:
https://new.usgbc.org/node/2613262?return=/credits/new-construction/v4-d...
Thank you for your question! I hope this helps.
Pamela Lippe
Presidente4inc
47 thumbs up
December 7, 2012 - 4:21 pm
So to be clear are you saying that it will be acceptable to capture water for reuse (rainwater harvesting) as a way to meet the credit? I don't see that anywhere in the definition of LID or green infrastructure.
Theresa Backhus
Sites Technical Specialist, LEEDUSGBC
66 thumbs up
December 7, 2012 - 4:32 pm
Yes, it is listed as an example approach in the LID definition:
"low-impact development (LID): an approach to managing stormwater runoff that emphasizes on-site natural features to protect water quality, by replicating the natural land cover hydrologic regime of watersheds, and addressing runoff close to its source. Examples include better site design principles such as minimizing land disturbance, preserving vegetation, minimizing impervious cover, and design practices like rain gardens, vegetated swales and buffers, permeable pavement, rainwater harvesting, and soil amendments. These are engineered practices that may require specialized design assistance."
https://new.usgbc.org/glossary/39#letterl
Pamela Lippe
Presidente4inc
47 thumbs up
December 10, 2012 - 12:38 pm
I still think that it would be helpful to make it clearer that rainwater harvesting is acceptable in the credit language rather than forcing people fo figure it out based on the glossary language. It is particularly confusing because i don't see how rainwater harvesting replicates "natural site hydrology processes" but I am happy to hear that it is acceptable since many projects will find it difficult, if not impossible, to infiltrate. That said, it will be an more expensive proposition for that type of project..
Scott Bowman
LEED FellowIntegrated Design + Energy Advisors, LLC
LEEDuser Expert
519 thumbs up
December 11, 2012 - 8:28 am
I had a similar concern about rainwater harvesting for the water efficiency credits, but in the last draft there was a change made that allowed alternative water sources for the WE credits. The WE prerequisites must be through reduction however. So there is something to use your harvested water for. I agree that this can be expensive, especially on larger projects, but can make a dramatic improvement in older urban areas where there is intense pressure on the infrastructure due to combined sewer and storm systems. Using rainwater harvesting systems in these applications in a distributed manor can reduce the need for huge wastewater treatment plants to serve surges during rain events.