Some Statistical Properties of Short-Duration Rainfall
Storm data and climatological quantities from both dense raingage networks and individual stations are used to elucidate some of the important problems in developing drainage design criteria for small areas. Examples are presented displaying the variability of rainfall rates for very short durations of time over very small areas. An “average” time distribution curve is presented along with relationships between rainfall amounts for durations from 2- to 60-min. One example outlines a procedure for estimating and comparing six quantities from series of annual maximum rainfalls for several short durations. The quantities include a frequency factor, 100-yr value, the probable maximum rainfall, and the observed world maximum rainfalls.