To develop a landfill facility, a lot of things need to be considered
from selection of site to ground water vulnerability. This article examines how spatial technologies, AVI method and DRASTIC model can be used in this process

Landfill isthe most common method for disposal of waste materials worldwide. Landfills are generally used to dispose of municipal waste like refuse, garbage and trash as they are biodegradable. But of late synthetic chemicals and other hazardous materials have also been detected at many sites. For developing a new landfill facility the selection of site needs lot of attention as it may pose long term threats to human health and the environment. A preliminary assessment of the possible environmental impact of a proposed landfill facility can be carried out using the spatial technologies. The vulnerability of ground water to contamination can be quantified by using the Aquifer Vulnerability Index (AVI) method and the DRASTIC model using geographical information system.

Requirements for a Landfill Site
A solid waste disposal site should address the demands of local population and it should also guarantee safety of human health and the environment. It requires geological and engineering expertise together with local community’s acceptability. The solid waste disposal facility should ensure that groundwater, surface water, air quality, floodplains and species are not adversely affected. Groundwater quality could get deteriorated by leachate leaking from a hazardous landfill and the quality of underlying aquifer must be considered in site selection. The landfill sites should be located outside floodplains. The proximity of surface waters and storm water runoff is also required to be investigated. Therefore, locations of pond, reservoir, dike and there proximity to landfills needs to be looked into. Other important parameters to be considered are topography and hydrogeology of the area. Rainfall characteristics, its distribution and evaporation rates need to be considered in locating a landfill. The landfill site should be located away from water supply wells. Over and above the techno- environmental constraints, the economic evaluation is also necessary for selecting the most suitable site. The criteria used to determine suitable areas for landfills should be based on the guidelines of the Central Pollution Control Board (CPCB) Government of India.

The other constraints are related to roads, open water, protected areas, urban and rural residential areas. The important criteria that are essentially required for site location are soil permeability and soil type, land use/land cover and distance to transportation routes. The permeability of the underlying soils and bedrock will greatly influence how much leachate is escaping a landfill site; therefore, preference is given to landform that is somewhat located ons flat or undulating land. The landfill site for example should be constructed on clay-rich soils with a minimum thickness of 5 meters and permeability lower than 0.05 meters/day. Landfills shall not be located within 100 meters of any major highways, city streets or other transportation routes. The land use and land cover must be known in order to determine which areas are more suitable for a landfill. Landfills should not be placed too close to high-density urban and rural areas and wild life sanctuaries to prevent future developmental problems. The US EPA has established the following landfill siting requirements for disposal facilities and practices: