Simulation of Contamination of Groundwater Using Environmental Quality Model

Ground water is an important source of water supply for municipalities, agriculture, and industry. Ground water contamination is the degradation of the natural quality of the ground water. While determining the degree of contamination, both the presence of a substance and its concentration must be considered. The level at which a substance could be harmful is different for each substance. Ground water contamination occurs, or can occur, when ground water in the zone of saturation is recharged with contaminated water or other liquid contaminants, or when a contaminant is placed or buried in the saturated zone. Contamination may result from wells, improperly sealed or abandoned and landfills that allow contaminated surface water to reach an aquifer. Hence hydrological and environmental simulation modelling needs increasing attention from the hydrology and environmental modelling communities. Present case study in a paper emphasises on groundwater contamination due to septic tank effluent. Groundwater pollution may be defined as the artificially induced degradation of natural groundwater quality. Pollution can impair the use of water and can create hazards to public health through toxicity or the spread of disease. Most pollution originates from the disposal of waste water which is being used for variety of purposes. Thus, the large number of sources and causes can modify groundwater quality, ranging from septic tanks to irrigated agriculture. In contrast with surface water pollution, subsurface water pollution is difficult to detect and is even more difficult to control, and may persist for decades. With the growing recognition of the importance of underground water resources, efforts are needed to increase to prevent, reduce, and eliminate groundwater pollution. II GROUNDWATER CONTAMINATION The occurrence of groundwater contamination and quality of groundwater has become major issues since some decades. Environmental contamination of groundwater due to extensive use of fertilizers, pesticides in agriculture and toxic chemicals in industry and in manufactured products has magnified the toxicity for plants, animals and society. Contaminants that can dissolve in groundwater will move along with the water, potentially to wells used for drinking water. A combination of moving groundwater and a continuous source of contamination can, therefore, pollute very large volumes and areas of groundwater. This presence and the transport of contaminants constitute a potential threat to human health and ecosystem. The quantity and the suitability of groundwater for human consumption and for irrigation are determined by its physical, chemical and bacteriological properties. A. GROUNDWATER MODELING