In my region, the DP requires that the major storm system be designed to convey runoff from the 1:100yr event (and minor system to convey the 1:5yr event). Acknowledging that 1:100yr is a statistic probability of that storm, the systems are nonetheless designed to manage the amount of precipitation that would exceed any lesser events. Would our design, then, meet the SSc6.2 requirement to prevent post-development peak discharge rate and quantity for the smaller 1 and 2yr storms? Or, does LEED require that we manage two(2), 1:100 year back to back events?

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Michael DeVuono

Regional Stormwater Leader

Arcadis North America

LEEDuser Expert

144 thumbs up

Tue, 02/25/2014 - 19:15

Lindsey, that is impossible to say, as these storm events are not linear in nature. You need to have whomever did your stormwater design for the 5 and 100-year storms submit calculations for the 1 and 2 year storms in order to qualify for this credit.

Lindsey Kindrat

Executive Director, Principal Sustainable Building Specialist

3 Point Environmental Inc.

LEEDuser Basic Member

3 thumbs up

Tue, 02/25/2014 - 20:14

Would a 100 year storm not drop more precipitation than a 1 and 2 year storm?

Michael DeVuono

Regional Stormwater Leader

Arcadis North America

LEEDuser Expert

144 thumbs up

Wed, 02/26/2014 - 13:49

Yes it is a higher rainfall depth. But Stormwater design is not a linear relationship. Frankly, if I were given the requirements to only reduce rate for the 5 and 100 year storms, the 1 and 2 would likely show a rate increase, because I would not detain those storms at all. You need to submit calcs for the 1 and 2 year storms. Anything else will cause you to be denied for this credit.

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FAQs about SSc6.1 :

System manages the 1:5 and 1:100 year event - compliant?

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