In recent years, due to climate changes, loss of vegetation, increase in urbanization and population growth near rivers, the frequency and intensity of floods have increased and significant damages have been done to urban infrastructures. Duration of rainfall and vegetation are among the important factors that affect the depth of flood and thus depth of inundation in Water Distribution Network. To investigate the effect of these factors on the depth and velocity of flooding, the 2018 Lorestan flood on the Kashkan River was modeled using HEC-RAS software to investigate the effect of each on the flooding depth of a pumping station. Different scenarios of changing the roughness coefficient (to represent inundation) and duration of rainfall had been implemented in the model in order to check the effect of each parameter on the depth of inundation. In this method, in addition to checking the changes in flood depth, flow velocity was also analyzed in the studied area. Based on the results obtained from the hydraulic model in different scenarios, with increase of the Manning coefficient by 2.72% between scenarios with the highest and the lowest roughness coefficient, the inundation depth increased by 10.3% and the velocity decreased by 3.44%. In the scenarios of duration of rainfall, with a decrease in the duration of rainfall by 30%, the inundation depth of flooding increased by 44% and the flow velocity decreased by 12.7%. Results showed that vegetation had more of an impact on depth and velocity of flood compared to duration of rainfall.