A Continuous Simulation Approach to Design Storm Calibration

Abstract

The paper suggests the opportunity to calibrate the design storm parameters and associated antecedent soil wetness conditions for each climatic situation of interest on the basis of the results obtained by means of a continuous simulation of catchment response, extended to a sufficiently wide spectrum of catchment characteristics. Assuming a suitable model to represent catchment response, calibration was performed by direct comparison between the peak flow probability distributions derived from design storm application and the related frequency distributions obtained through continuous simulation, in order to reach a reasonable agreement between the two. The results show that this methodological approach is fully satisfactory. Generally speaking, the synthetic storm parameters appear to be quite dependent on catchment loss characteristics, and especially on potential infiltration, but are almost insensitive to pervious soil percentage and to other factors related to net rainfall catchment response. For practical purposes, similar calibrations should be performed with reference to the main climatic situations of each region of interest. In this way the results could be applied, under similitude assumptions, to any specific location where detailed rainfall information is lacking or insufficient.