Correlation between runoff volume and land use changes using SCS-CN method for Sungai Gombak catchment

Abstract

This research focuses on river modeling using the input precipitation and land use system Soil Conservation Service Curve Number (SCS-CN) using InfoWorks RS (IWRS) and Geographical Information System (GIS). The purpose of this study is to measure the volume of runoff based on the year selected for the Sungai Gombak model with changes in land use base. Sungai Gombak is part of the upper basin of the Sungai Klang. The Sungai Klang basin area has undergone significant urbanization, especially upstream in Sungai Batu, Sungai Gombak and Sungai Klang. This urbanization is the most significant changes in land use happening within the basin of the lake. For the Sungai Gombak catchment, the transformation of the undeveloped area that lead to Sungai Gombak changing the amount of runoff. Six rainfall stations were selected to model the river and then the average catchment rainfall for each catchment was interpolated using Thiessen method from the available rainfall station. Three rainfall events were chosen based on the flood history reported by the Department of Irrigation and Drainage (DID) in the Sungai Gombak. The results indicate that the CN value rises from year to year due to changes in landscape patterns that indirectly influence ecological processes and decrease the stream flow time concentration.