Generation of synthetic design storm hyetograph and hydrologic modeling under HEC HMS for Ziz watershed

Abstract

This article proposes a methodology for generating hourly rainfall from daily rainfall data. It was evolved as a tool for managing flood risks on Ziz catchment, by means of Intensity-duration-frequency curves (IDF) and designed hyetograph of Chicago. The study area is located in the south-eastern part of Morocco, and did not have a monitoring station for hourly rain measure, the methodomogy consist of determinating the rainfall intensity for 24 h using IDF, then estimating the hourly rainfall using Chicago formula, in order to assess the accuracy of the method the resulting hyetographs was introduced into the semi-distributed hydrological model HEC HMS to simulate hourly flow, which was compared to the observed one. The obtaining results exhibit that the observed value is positively correlated with those obtained by the above method, as shown by the correlation coefficient and the Nash-Sutcliffe. This approach can deal with instantaneous water management issues by tackling flood risks and providing an appropriate range of data for the dam’s management.