Not only does the NOAA have this data, but it is free, readily available AND goes up to the 1,000-year event! This is news to me.
According to page 9-535 of the Pennsylvania Stormwater
Best Management Practices
Manual
DRAFT - JANUARY 2005
9.5 Precipitation Data for Stormwater Calculations
In 2004 the National Weather Service’s Hydrometeorological Design Studies Center published updated
precipitation estimates for much of the United States, including Pennsylvania. NOAA Atlas 14
supercedes previous precipitation estimates such as Technical Memorandum NWS Hydro 35 and
Technical Papers 40 and 49 (TP-40 and TP-49) because the updates are based on more recent and
expanded data, current statistical techniques, and enhanced spatial interpolation and mapping
procedures. (Bonnin et al., 2003 and NWS, 2004) The “Precipitation-Frequency Atlas of the United
States,” NOAA Atlas 14, provides estimates of 2-year through 1000-year storm events for durations
ranging from 5 minutes to 60 days as shown for Harrisburg in Table 9-2 (available online at http://
hdsc.nws.noaa.gov/hdsc/pfds/). Users can select precipitation estimates over
300 observation sites, by entering latitude/longitude coordinates, or by clicking on an interactive map
on the Precipitation Frequency Data Server.
Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve
Yes, I know about that web site. However, it doesn't give IDF curves. It gives rainfall totals per storm event for given storm durations. I need In/hr on the y-axis and time on the x-axis.
Since you're asking about IDF data, I assume your regulations require the use of the Rational Method? If so, the regulations "should" include references for all necessary data.
Otherwise, you might try posting this in the Storm/Flood Engineering forum.
The Hydraulics unit performs hydrologic and hydraulic analyses for the proper sizing of all bridges, culverts and other drainage facilities needed on state and local highways. This section also provides expert advice to any Agency unit in the areas of water hydraulic resources, scour analyses and drainage issues.
