Calibration of SWMM5 for local parameters at Sungai Kayu Ara, Damansara Selangor

Abstract

Urban storm water modeling is one of the alternatives management and design tools in water engineering field. Users have so many choices in selecting the appropriate model base on their application purposes. One of the among popular model is Storm Water management Model (SWMM) from primarily in urban areas. SWMM is a dynamic rainfall-runoff simulation model that may be used for a single event or long-term (continuous) simulation for either runoff quantity or quality or both. In addition, the new SWMM version which running under Windows based, provides an integrated environment for editing study area input data, running hydrologic, hydraulic and water quality simulations, and finally, viewing the results in a variety of formats. The sensitivity analysis is carried out in this study to determine the major influence parametes to runoff depth and peak flow. By successfully running the sensitivity analysis, the selection of calibration parameters can be minimized. The results indicate that the sensitivity analysis showed a similar trend like the other overseas studies. This means that the main parameters for this model are related to the physical catchment caracteristics. Furthers, the calibration process for local parameter indicated that the results are in the allowable ranges. The mean result for Relative Error (RE) and Absolute Relative Error were found fewer than 10 and 25 percent respectively. This initial study indicated that this modeling process is successful in Malaysian conditions. In sum, the SWMM5 usages are applicable with local parameters and successfully mimic the real events. By playing with the percentage of impervious, which is the most sensitive parameter to either runoff depth or peak flow, of the cacthment area, the model can predict and further, could be utilized as a flood forecasting tool.