Steady State Groundwater Flow Modeling of an Ex-Landfill Site in Kuala Lumpur, Malaysia

Effective and rational management of groundwater resources require adequate information on the groundwater flow interactions with surface water and chemical species in the flow regime. The hydrologic conditions beneath the unlined ex- landfill site in Jinjang Kuala Lumpur were investigated to understand the groundwater flow and geochemical setting in which contaminants transport in the groundwater may occur in the ex-landfill. The MODFLOW 2000 was used to construct the groundwater flow regime. The model was set up and calibrated as a three (3) layer steady-state MODFLOW model. The MODFLOW model revealed that the hydraulic gradient of the groundwater flow in the landfill site is to the north-east, towards Jinjang River which is located on the eastern part of the landfill. There is also groundwater movement towards the south-east of the landfill towards the Nanyang and Wahyu Ponds. It was concluded that quick action is deemed necessary to protect Jinjang River and Nanyang Pond which are hydraulically connected with the same aquifer and the geochemical setting in which contaminants transport may occur in the ex-landfill is in the same direction as the flow of the two water bodies. Recommendations are suggested to reduce the groundwater level by pumping below the height of the river bed, so that there is no contamination to the river and pond via recharge of groundwater into the river, instead the river should recharge to the groundwater.