ABSTRACT
The structure of a rainstorm is defined as the distribution of rainfall depth in time. This distribution has a visible influence on the hydrological behavior of a watershed (for example, see Figure 4.9). Figure 4.10 shows a comparison of two precipitation events with identical duration and volumes, but vastly different temporal distributions of the rainfall. In one case, most of the rain volume falls on the ground during the beginning of the rainfall period, while in the second case, most of the high intensity rain falls toward the end of the event, when the soil has already been saturated, at least partly. As a result, the second event presents – potentially – a much higher risk than the first of higher flood discharge, because at the moment of maximum rainfall intensity, the water holding capacity of the soil has already been reduced by the earlier rainfall.
