Impacts of LULC Changes on Inflow Simulation of the Timah-Tasoh Reservoir Using the HEC-HMS Model

Abstract

This study assess the impact of land use and land cover (LULC) changes on inflow simulation in the Timah-Tasoh reservoir, the largest reservoir in Perlis, Malaysia. This reservoir serves multiple purposes, including flood control, water supply, irrigation, and recreation. The study focused on the upper sub-catchments within the reservoir’s catchment area, using the Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) and ArcGIS to simulate rainfall-runoff under different LULC scenarios. The study are determine hydrological parameters, evaluate the performance of the HEC-HMS model during calibration and validation, and analyze the effects of LULC changes on inflow. Data from 2001-2019, provided by the Department of Irrigation and Drainage, Malaysia, were used for model calibration and validation. Model performance is satisfactory, with R-values ranging from 0.49-0.80. The study found that deforestation increased inflow by 3.9 %, while afforestation reduced it by 1.4%. These findings provide valuable insights for future hydrological modeling and land use planning in the Timah-Tasoh catchment area.