LEED CREDIT 6.1 QUANTITY 1

[urbanresource]

I have a site located in the County of Orange (California) with existing Imperviousness less than 50%. My question pertains to Leed Credit 6.1. Please see my questions below. I would greatly appreciate any feedback.

The requirement is to provide discharge rate and volume for the existing and proposed conditions. They require the 1 year and 2 year 24 hour events. Does anyone know how to determine the 1 year event? I have no problem with the 2 year event. I am using AES Ratscx. Thanks!

 

[psmart]

Whatever source you're using for the 2-year depth should also have the 1-year depth.

If you need another source for rainfall data try

http://hdsc.nws.noaa.gov/hdsc/pfds/

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[cvg]

my version of ratscx does not support 1 year. you may have to do this by hand. use the precipitation data from NOAA 14

 

[urbanresource]

Thank you both for your responses. Unfortunately, I checked the NOAA website, and my particular project does not fall within the data range of NOAA 14. And NOAA Atlas 2 doesn't provide the 1 year 24 hour duration. Please let me know if you have any other suggestions. I may just be out of luck for this particular project location, and may just consider the 2 year 24 hour duration. Thanks.

 

[RWF7437]

Try downloading NOAA Atlas 2, Vol. 11.

http://www.nws.noaa.gov/oh/hdsc/PF_documents/Atlas2_Volume11.pdf

You'll then have to print out and use the maps, which is cumbersome and inconvenient but is the best information available.

If that doesn't work, call Orange County and ask them if they have the data you need.

good luck

 

[cvg]

how about plotting the 2 - 100 year IDF data on log-log paper for various Tc's and just extrapolate for the 1 year storm?

 

[psmart]

The NOAA PFDS site includes 1-year data for each state that it covers. Are you intereested in a state that isn't listed?

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[cvg]

psmart, NOAA 14 only covers the inland portion of southern california, not the coast which is where Orange County is located. In addition, NOAA 2 which does cover the coast does not have 1-year data.

 

[urbanresource]

CVG,

Thanks for clarifying. That is exactly where I stand. I will have to interpolate to determine the 1 year data, using the 2 year to 100 year IDF, as you suggest CVG. Or I can obtain precipitation data from the nearest rain gage, and develop my own 1 year precipitation from the data.

 

[RWF7437]

"If that doesn't work, call Orange County and ask them if they have the data you need."


Why not do this ? Might save you hours of work.

The website clearly says that NOAA 2 does have 1 year data but CG may be right and the website wrong. If CVG is correct wouldn't a call to whoever is requiring you to do these calculations ( is that Orange County ?) be the most direct route to an answer ?

good luck

 

[cvg]

you can download NOAA 2 from the link I provided. However, it definitely does not have 1-year recurrence interval precipitation data. However, I agree that calling Orange County Flood Control District (if they are the ones requiring this 1-year analysis) should be done.

 

[urbanresource]

This is being done for LEED certification (USGBC), so the County of Orange will not be reviewing this. However, I have put in an email to the County to see what I can get my hands on. Wish me luck. I was able to download NOAA 2 from the link, and it does not provide data for the 1 year recurrence. Thanks very much for all the feedback.