GIS Techniques for Groundwater contamination Risk Mapping

GIS Techniques for Groundwater contamination Risk Mapping


VI Semester,Geo Informatics,
College of Engineering, Guindy,
Anna University,
Chennai – 25

While water supply is a crucial issue, there is also evidence to suggest that the quality of groundwater supplies is also under threat in recent years. This is a result of salinisation and an increase in the use of agrochemicals. This paper attempts to produce groundwater vulnerability and risk maps using DRASTIC system. These maps are designed to show areas of greatest potential for groundwater contamination on the basis of hydro geological conditions and human impact. Geographical Information System (GIS) is used to create a groundwater vulnerability map by overlaying the available hydro geological data from thematic maps. The resulting map is then integrated with a landuse map to assess the potential risk of groundwater to pollution in the area. The final map shows interesting results and stresses the need for the GIS to test and improve on the groundwater contamination risk assessment methods. This is a very important contribution of GIS towards environmental management.

Groundwater is generally a safe source of drinking water. Certain problems have beset the use of groundwater to human users and to the environment due to its over-use or overdraft. Groundwater vulnerability refers to the sensitivity of groundwater to contamination. The seriousness of the impact on water use depends on the extent and magnitude of the pollution and the value of the groundwater resource. Groundwater vulnerability mapping is used as a guide in determining which areas are more susceptible to groundwater contamination within the mapped area. This paper aims at mapping groundwater contamination using GIS techniques

DRASTIC is an empirical model developed by U.S. Environmental Protection Agency. It is widely used for evaluating relative groundwater pollution susceptibility by using hydro geological factors. DRASTIC is an acronym for the most important hydro geologic features which control groundwater pollution.

These features are: