Forum discussion
NC-2009 SSc6.1: Stormwater Design—Quantity Control
Hello, We have a project in Sri Lanka where we try to attempt this credit via percentile rainfall event option. However we find difficulty of getting continuous 30 year rainfall data. There are some months that the rainfall data are not available. So in that case can we still calculate the percentile storm event using the available data or attempt to consider about extra couple of years (say 32 years instead of 30 years) in order to compensate for the missing months of data?
Thank you.
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Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
187 thumbs up
July 19, 2013 - 7:07 am
This seems reasonable to me, provided it is not the same time period missing every year.
If it is just random months, I think you will be able to zero in on a value even without going past 30 years, but if you have the additional data, you may as well use it.
Magda Aghababyan
CEOCo-Energi (Pvt) Ltd.
15 thumbs up
July 20, 2013 - 8:56 am
Thanx Michael. I mean I wasn't sure if there is a minimum number of data points required for this calculation to be accurate on statistical basis. Do you know about such requirement?
Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
187 thumbs up
July 20, 2013 - 9:28 am
As my statistics professor used to say "the more, the better."
As far as LEED is concerned, I do not believe there is specific number of data points required.
I will look at the EPA document (which will be the standard for v4 rainwater) they have a methodology outlined in there, they may specify a certain number of data points, but I think they just say 30 years as well.
Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
187 thumbs up
July 22, 2013 - 8:35 am
http://www.epa.gov/oaintrnt/documents/epa_swm_guidance.pdf
This is the EPA Section 438 document. It has methodology for calculating percentile storms, with links to other docs to assist with the methodology. LEED v4 will be based on this document,