Estimation of amount of Peak Discharge and the Introduction of Flooding Model in Razavar Watershed

This study was done to identify effective factors on flooding in Razavar basin in the north of Kermanshah province by using SCS model. For flood estimating، primarily Razavar watershed was divided to sub-watersheds with stream orders of 5، 6، and 7 then effective factors such as area، slope، CN، lag time، time of concentration، density of rainfall، land use، slope، geology، and vegetation were studied and the peak flood discharge was estimated by SMADA software. Peak flow estimation by SCS method showed maximum of 100 years return period peak discharge of Razavar watershed with 8 stream order was 691. 85 m3/s and the minimum of 100 years return period was related to sub-watershed number of 10 with 5 stream order about 28. 9 m3/s. For determining the most effective factor in the flood basin and to predict the amount of discharge and present a suitable discharge model as a dependent and others as independent variables we introduced these values and analyzed them by SPSS software. Simple regression، multiple and logarithmic، forward and step by step models were applied for the basin. It should be noted that the models presented with a confidence level of 0. 01 percent were acceptable. The results show that the area، lag time، and CN are the most effective factors in flooding.