Effect of Different Sustainable Rainfall on the Peak Flow

Abstract

Rainfall is the main source of normal and flood surface flow. The storm intensity and sustainability in addition to the watershed properties soil type and land use have a direct effect on the peak flow. In the first stage of this research the TR-20 model and HEC-1 model based on both SCS method and Snyder method operating under watershed modeling system (WMS). The models were calibrated based on a number measured hydrograph for Khashban which is one of sub-basin of Alkhoser seasonal river near Mosul city, and Solak in Sinjar- Republic of Iraq. The comparison between the two model based on Nash model efficiency E%, determination coefficient (r2) and the t-test values for the measured on predicted value of peak flow, time of peak flow and runoff volume. The result showed that TR-20 model is the best. In the next stage, the TR-20 model was applied for the two watershed for different value of rainfall intensity, duration, and curve number for soil conservation service (SCS) method that reflect the effect of soil type, initial water content, land use and plant cover. The aim is to obtain the peak flow the watershed for different value of consider variables to an equation of peak flow for different values of rainfall duration.