In the calculation section of the guide it says that we need to have the rainfall event interval to calculate the minimum drawdown rate.To what is this event interval refers to? is it the maximum gap within a year or a average gap interval within a year which can be determined by the rainfall data.(we have annual rainfall data).
Further i am unclear of the fact that we need to have the system to address 15% of both AVERAGE YEAR and 2-YEAR,24-HOUR DESIGN STORM..
how to we cater to both of that requirements at once??
please post your ideas..
Jenny Carney
Vice PresidentWSP
LEEDuser Expert
657 thumbs up
March 25, 2010 - 2:27 pm
Hi Rashid,
The rainfall event interval only comes into play if you are collecting rainwater in a cistern or other detention facility as part of your stormwater management strategy. If that is the case, you basically need to know the interval between rainfalls so you can figure out if you empty your cistern before the next rains come. If you aren't collecting rainwater, you don't need to worry about this particular aspect of the calculations.
Regarding the average year vs. the 2-year, 24-hour design storm, in most cases it's appropriate to focus on showing compliance during the 2-year, 24-hour storm, with the idea being that if you can handle that volume on water you'll also be able to deal with the volume of rain that falls during the average year.
Hope this helps.
RASHID HAMEEN
60 thumbs up
March 26, 2010 - 12:31 am
Thanks Jenny, as you have mentioned it seems like it will be better for us to comply with the 2 year 24 design storm in setting up our rainfall collecting system..
American University
SustainabilityAmerican University
56 thumbs up
October 31, 2012 - 3:45 pm
We are collecting rainwater in a cistern or other detention facility as part of our stormwater management strategy...So what IS a reasonable interval between rainfalls? Could one look up the daily average rainfall and assume that the interval is 24 hours? If using the 2 year-24 hour design storm what would the interval be? 2 years?
I see that in LEED Online the only space for retention facilities is a cell asking "Volume captured (cubic feet)" so I'm not even sure where the drawdown information comes into play?
Louis Haag
LEED APBureau Veritas
June 3, 2014 - 3:56 am
Hi Jenny,
We can't understand the difference between the 2 documents to upload SSc6-3 and SSc6-4.
Both have the same description "Provide a copy of the most recent stormwater and a log showing that any needed maintenance or repairs were performed within 60 days of the inspection that uncovered them.
Any idea?
Thank you.
Noriko Nagazumi
Woonerf Inc.74 thumbs up
November 21, 2014 - 4:33 am
Louis,
We're also puzzled by the online form. I guess it is a half-baked online form...