Assessment of Geological, Hydrogeological and Geotechnical Characteristics of a Proposed Waste Disposal Site: A Case Study in Khon Kaen, Thailand

Occasionally, a selected site suitable for landfill construction is severely protested against by locals. This issue can cause the proposed landfill to be relocated to an environmentally sensitive area. The proposed Khon Kaen waste disposal site has been planned as an integrated municipal solid waste management system, although the site is situated in an environmentally sensitive area. A site assessment can guarantee the suitability of waste disposal construction, with procedures that aim to assess the potential of geological and hydrogeological characteristics, geological barriers, geotechnical properties of material for landfill construction and groundwater conditions for future monitoring of such facilities. The study area is located on foothills where no geohazard or seismic impacts have been recorded. The geology is composed of sandstone, siltstone, and mudstone bedrocks mostly overlain by unconsolidated sediments. The natural geological barriers are clay and regolith. The clay layer lies locally and is rather thin, at around 2-3 m thickness. The study area is situated in an area that is highly vulnerable to groundwater pollution. The distinct weaknesses of this site along the foothill are a prominent transport path of shallow flows; high groundwater fluctuation, especially during the rainy season; that it is a recharge area with a high fracture zone; and the high permeability of colluvium. The material characteristics in the site make it suitable for use as landfill cover and liner. Following compaction, the coefficient of permeability ranges from 1.2 x 10(-7) to 7.1 x 10(-7) cm/s, which is acceptably impervious.