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FAQs about SSc6.1 :

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

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?

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Forum discussion

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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