How is intensity determined for a time of concentration less than the lowest duration value in IDF T


Product(s):StormCAD, CivilStorm, SewerGEMS
Version(s):10.XX.XX.XX and 08.11.XX.XX
Area:Calculations

Problem

If a catchment has a time of concentration less than the smallest duration in the IDF table, how is the intensity determined?

For Example:
If the following catchment's Time of Concentration is 5 minutes, and the lowest duration in the IDF table is 10 minutes, then how is the intensity calculated?

Solution

The intensity, corresponding to a time of concentration that is less than the lowest duration value in the IDF table, is determined by extrapolating the line from the two lowest points of duration and intensity in the IDF table.

See Also

The IDF table equation storm data isn't producing the correct intensities in my catchments.