StormNET includes a rainfall database with with over 3,500 rainfall recording stations across North America for the 1, 2, 5, 10, 25, 50, and 100 year return frequencies. This allows you to quickly determine design rainfall based upon your study location. We developed this database over a year, and are continuously updating it with updated rainfall data when we receive it. While this is not exactly an IDF curve, you can use this data for all other stormwater methods except Rational and Modified Rational (i.e., SWMM, TR-20, TR-55, Santa Barbara UH, HEC-1, etc.).
If you are required to use the Rational and Modified Rational method, then you will need to develop an IDF curve. Generally, you need to locate the actual IDF data for your site from your state or local stormwater regulatory agency. In some cases, the applicable stormwater regulations will provide IDF coefficients that you should use in your design. However, if this IDF data is unavailable, raw IDF data is available from the NOAA NWS Precipitation Frequency Data Server (PFDS) for about 1/3 of the states at the following link. If your site is in one of the "blue" states, then simply click on the state that your project is in, then from the displayed state map you can then zoom in and select the location of your site. The PFDS will then provide you with the IDF data.
PF Data Server Home - HDSC/OHD/NWS/NOAA
Linear Mode
