Evaluation of soil characteristics and groundwater criteria on landfill siting using geographic information system and hydrologic evaluation of landfill performance computer program

Abstract

This research aimed at an evaluation of the potential sites for sanitary landfills in Khon Kaen province using Geographic Information System (GIS) and Visual Hydrologic Evaluation of Landfill Performance (HELP) computer program. Initially, the environmental sensitive areas for landfill sites were mapped based on the criteria of Pollution Control Department (PCD) together with some additional criteria from Changwat (province) Action Plan for Environmental Quality Management (CAPEQM) project. With the GIS approach, 3 levels of sensitive areas were categorized as the highest, high, and medium to low environmental sensitive area. In order to focus more specific criteria on groundwater level, the new environmental sensitive areas could be then created. With the groundwater level overlain onto the initial map, the medium to low sensitive area was significantly decreased approximately 79% (from 2689.78 km[superscript 2] to 572 km[superscript 2]). Afterward, the impacts of the sensitive areas were assessed in terms of volume of leachate percolation using Visual HELP computer program. Soil profile of the 7 selected sites were carried out, they indicate the different soil types of individual sites. Under the same conditions of inputs (weather, leachate, characteristics, structure of landfill) and a little different in soil types, the results simulated by Visual HELP that the percolation volume of all 7 sites were not much different in the range of 9.84 million cubic meters (MCM) to 10.3 MCM. With the mitigation measures by adding the liner of geo-membrane, the simulating water generated was decreased in the range of 19 to 38%. Site 5 and site 3 are the most potential sites in order to less water percolation. They are the most suitable with minimal impact to environment in both of without and with mitigation measures (geomembrane lining), respectively. It could be concluded that ground water level and soil characteristics are the important criteria for landfill siting. GIS and Visual HELP program are the meaningful tool to facilitate landfill siting. The study also guided the new useful siting process technology for disposal facilities.