NOAA Precipitation Frequency Storm using Hydrocad

[JALeng]

I'm modeling a watersheet using Hydrocad software to determine the increase outflow due to a development. The local regulation require the use of precipitation frequency data obtained from NOAA. How I model 24h storm using frequency storm data?

 

[psmart]

You will need to look carefully at what your regulations require.

Most studies continue to use the standard SCS Type I, II, or III rainfall distributions. In these situations, all you need to do with the NOAA data is to enter the 24-hour rainfall depth for each event.

In rare cases, you may need to develop a custom rainfall distribution based on the NOAA data. Check your regulations to to see if this is required.


Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[JALeng]

HEC-HMS provide several options to calibrate the meteorologic mode. One of them is precipitation frequency storm. This method provide the option to specify the precipitation for 5-min, 15-min, 1-hour, 2-hour, 3-hour, 6-hour, 12-hour and 24-hour. Using this data, I have modeled a watersheet with the parameter of SCS curve number and SCS unit hydrograph. These method of analysis is posible using Hydrocad.

Attached are the local regulation that describe the guidelines to prepare H-H study

 

[psmart]

The next HydroCAD release will have the ability to generate a synthetic mass curve (for use with the SCS method) based on the data you describe. In the mean time, if you send us a NOAA data file we can do the conversion and send you the HydroCAD-compatible rainfall files. For details please see

http://www.hydrocad.net/rfdownload.htm

Please note that if you already have a mass curve from another another program, you may prefer to convert this to a HydroCAD format, rather than re-generate the curve. For details please see

http://www.hydrocad.net/rainfall.htm

Peter Smart
HydroCAD Software

http://www.hydrocad.net