Simulation of Drainage System Using Storm Water Management Model (SWMM 5.1)

Abstract: Urban flood is one of the major problems in Guwahati city at present. The topography of the city is such that rainwater cannot drain out easily from the city. With rapid growth of the city, along with people cutting and constructing houses in the surrounding hills, result in high sediment yield from the immediate upper catchment, adding another dimension to this problem. The need for a proper storm water disposal drainage system is at prime in Guwahati. Therefore innovative planning and efficient design of the drainage network is necessary. An effort has been made to study finer details of the area by investigating drainage systems of various parts of the city. The existing drainage channel is studied and simulated using SWMM 5.1 modeling software. The model is simulated for rainfall of two-year return period of interval one-hour design storm intensity. Frequency analysis is performed using best fitted distribution i.e., Gumbel’s distribution for different return periods and the frequency values are used for development of IDF (intensity-duration-frequency) curves. The city is divided into major flood prone areas according to ASDMA and then modeling is done with respect to different return period of rainfall. From simulation it is found that the existing drainage of the city is not efficient to drain out the storm-water completely, the primary cause of urban flood in Guwahati city