Storm Water Management Model sensitivity to infiltration methods and soils impermeability: the case of Tangier experimental basin,Morocco

The storm water management model (swmm) uses many parameters and functions that require selecting those that significantly affect the generated peak flows of the design of storm water sewerage in urban areas. in this paper,we are interested in the infiltration loss function through the study of swmm sensitivity to different infiltration method integrated into this model,namely horton,scs and green-ampt methods. the case study concerns the tangier experimental basin soil type located in morocco. for sandy and clayey soils,the horton and green-ampt have given the same infiltrated volumes and peak flows. however,for a clayey structure,the scs gives maximum deviations of infiltrated volumes of 125% compared to the horton and green-ampt. this variation causes maximum deviation of peak flows not exceeding -10%. simulation results also showed a discrepancy in the green-ampt method which increased volumes infiltrated cause increased peak flows. swmm model sensitivity studies for loamy soil showed that the maximum deviations of infiltrated volumes are of 7% for the scs and 12% for the green-ampt compared to the horton method. these deviations generate a variation of peak flows respectively of -7% and 2%. consequently,we have retained the horton method. the scs method can be used by modifying the cn parameter for clayey soil at 91 instead of 83. © 2017,university of mohammed premier oujda morocco.