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Rational Method Analysis and NOAA Atlas 14


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I am using the Rational Method Analysis of the Hydraulic Toolbox. Under the IDF curves I see that NOAA Atlas 2 Data is an option, but not NOAA Atlas 14. The paragraph below can be found on page 31 of the Desktop Refernce Guide. Any idea when NOAA Atlas 14 data will be made available in the Hydraulic Toolbox?

Thank you,


The Rational Method Calculator allows the input of precipitation

information from a variety of sources. Hydro-35 for the

Eastern United States, NOAA Atlas 2 for the Western United

States, and user defined precipitation values from other sources

such as NOAA Atlas 14 (various regions of the United States).

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If you're using NOAA Atlas 14, you could use either the Hydro-35 or the NOAA Atlas 2 method. These methods use empirical equations defined in the FHWA HEC 12 document describing how to convert Hydro 35 or NOAA Atlas 2 data to a full range of IDF curves. However, it would be better to use the User Supplied Data option and enter all the data for the recurrence interval you're working with directly into the IDF computation calculator in the toolbox since the NOAA Atlas 14 data values are computed from long-term rainfall observations by NOAA that were not available at the time of the NOAA Atlas 2 or Hydro 35 development. So the NOAA Atlas 14 option is in the toolbox, it's just called the "User Supplied Data" option.

Let me know if I can help with anything else,


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