40. Width Parameter Analysis on Runoff Model for Storm Water Drainage System

The paper focuses on the width parameter study of runoff model, including the calculation and selection of width for subcatchments, subcatchment size selection, as well as equivalence of width for storm water drainage planning system. Varied methods of calculation for typical subcatchments are discussed and analyzed when surface runoff equation is solved. It found out that width parameter in runoff model is key factor that determines runoff peak flow which is very important for storm water drainage system planning and designing. The effect to runoff by the subcatchment size is also analyzed and an appropriate size is suggested as well. And the equivalence of width is studied as well which can avoid the inaccurate runoff flow for large scale subcatchments, especially for planning drainage system. Two cases of storm water drainage system are chosen to simulate. The simulation proves that runoff flow can be fit well between large scale and small scale subcatchments of storm water drainage system if equivalence of width is adopted in drainage model. This paper can provide some technical reference and support for storm water drainage system planning and modeling.