Simulation of Urban Drainage System Using SCS Hydrograph Method

Most of the computer models can fully account for the quantitative aspect in all the hydrologic and hydraulic design stages. The aim of this paper is to evaluate the capabilities of PONDPACK model to analyse the drainage network and pond capacity to cater stormwater runoff from residential areas. Based on actual and design rainfall data, PONDPACK can generate the peak discharges for each sub-catchment for pre and post development. PONDPACK model can produce the analysis of drainage network using Rational Method and SCS hydrograph methods. Pond routing can be generated using Modified Puls Method or Muskingum Method. Result has shown PONDPACK performed well using SCS Hydrograph method compared to Modified Rational Method where it can generate the peak runoff for each sub-catchment. Besides, it also can produce flow and storage routing for each link and pond system. However, Modified Rational method can only generate peak discharge from single catchment area. Since this method is not able to generate hydrograph, it is also not applicable in performing flow routing. In 20 years ARI, detention pond capacity will achieve up to 2800 m3. PONDPACK is applicable in the design and analysis of drainage network and pond system with some modifications such as the CN values to suite with Malaysian condition.