Development of IDF Curve

IDF curve represents the relationship among the intensity-duration-frequency of rainfall, can be developed if we have point rainfall data for long period.

The maximum depth-duration relationship is first determined for different storm duration, for each of these years. Then, we can proceed to determine the mean and standard deviation of annual maximum depth for each rainfall duration.

After that, we need to choose the return period we interested in, and calculate their corresponding frequency factor. Rainfall intensity for a specific return period and storm duration can be calculated based on the mean, standard deviation and the frequency factor. We can then proceed with plotting the IDF curve.

We may also attempt to fit the IDF curve using general formula. One of the easiest ways to do this is by using Microsoft Excel Solver.

The following shows the steps to develop IDF curve from point rainfall data. Watch the video above for full details.

Rainfall intensity calculation for specific rainfall duration and return period
IDF curve
Curve fitting using Microsoft Excel Solver


Post a Comment

0 Comments