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FAQs about SSc6.1 :

Why do the requirements focus on 1-year and 2-year, 24-hour storms?

Why include the 1-year storm in the credit requirements? Won't management practices for the 2-year storm be effective?

How can green roofs count as a stormwater control measure?

How can I achieve compliance if my project's stormwater control measures are outside the LEED project boundary?

I have 100-year data—how do I convert to 2-year?

Is it an acceptable strategy to capture the rainwater into tanks and discharge it into the public sewers after the rainstorm reducing the peak discharge?

Are there special considerations for international projects?

What performance threshold do I need to achieve for an Exemplary Performance point?

The calculations for this credit are always a headache! While our projects are usually awarded the credit, the equations in the LEED Reference Guide are helpful mostly for sizing a reservoir or cistern, but don't help you get to the final results. Does US

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CS-2009 SSc6.1:Stormwater Design—Quantity Control

Existing Imperviouness

Markus Henning

M.Eng Facility Management LEED AP BD+C | LEED GCP

Alpha Immobilien Consulting GmbH

LEEDuser Basic Member

19 thumbs up

February 10, 2012

My question is. The Guide says choose Case 1 Sites with Existing Imperviousness 50%or less or Case 2 Sites with Existing Imperviousness greater than 50%. Refers the Existing Imperviousness [%] to Pre or Post development of the site? Our project is located on a green space with large parts of meadow. Must we use Case 1 or Case 2. Thank you for any suggestions.

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Emily Catacchio

Sustainability Specialist

Wight and Company

LEEDuser Basic Member

415 thumbs up

Sat, 02/11/2012 - 01:22

Existing means "pre," as in, before your project. Does that help?

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