The Chicago design storm is a design storm distribution widely used by practicing drainage engineers. This representation of the temporal distribution of rainfall was proposed by Keifer and Chu in 1957. They developed a storm pattern which would preserve the maximum volume of water falling within a specified duration, the average amount of rainfall before the peak intensity and the relative time of the peak intensity.
To determine the time distribution of rainfall and preserve the previously mentioned characteristics, they adopted the empirical IDF curves. By using IDF curves, they stayed with a procedure and concepts engineers were familiar with and is simple to obtain and therefore, it has become widely accepted for use in engineering practice.
