THE INFLUENCE OF STORM TEMPORAL PATTERNS ON CATCHMENT RESPONSE

Previous investigations have shown that an estimate of the catchment r esponse to a storm event can be obtained from a consideration of kinem atic waves flowing over planar surfaces. For a singular plane, analyti cal solutions have been presented previously for storm events with a c onstant intensity of rainfall excess. However, these solutions have li mited applicability owing to the non-uniform distribution of precipita tion and, hence, rainfall excess in most real storm events. Analytical and numerical solutions for a number of non-uniform patterns of rainf all excess are presented. Solutions obtained show that the pattern of rainfall excess has a considerable influence on the catchment response . This influence is evident in the different time-to-peak of the resul tant runoff hydrographs and in the hydrograph shape itself. Therefore, the time of concentration is not a constant characteristic of the cat chment which can be determined without consideration of the temporal p attern of rainfall excess. Finally, the predicted hydrographs obtained for variable rates of rainfall excess have higher peak flow rates tha n that obtained for a constant intensity of rainfall excess.