Analysis of groundwater quality in the ambuliyar watershed, Tamil Nadu, India using GIS

Groundwater is the most important natural resource used for drinking by many people around the world, especially in rural areas. An attempt has been made in this research paper to understand about the groundwater quality of the Ambuliyar watershed in parts of Thanjavur and Pudukkottai districts, Tamil Nadu, India. Groundwater is the major source for domestic and agricultural activities in the area. The water samples were collected from PWD (Public Works Department). These samples were analysed for electrical conductivity, pH, total dissolved solids (TDS) and Hardness and major cat ions like calcium, magnesium, sodium, potassium and anions like bicarbonate, chloride, nitrate and sulfate in the laboratory using the standard methods given by the American Public Health Association (APHA). The groundwater locations were selected to cover the entire study area and attention was given to the area where contamination is expected. Geochemical parameters exceeding permissible limit have been identified in most of the locations indicating higher ionic concentration. TDS, Mg, Na, K, Cl, SO4 and EC exceed the maximum permissible limit. pH, NO2, NO3, Ca, Hardness, HCO3, CO3 and F are within the permissible limit of  World Health Organisation (WHO, 2008) and Bureau of Indian Standard (BIS, 1991). The results were evaluated in accordance with the drinking water quality standards given by the World Health Organization. The present study reveals that the groundwater distribution pattern and concentration of different geochemical parameters and demarcation of the higher concentration zones were identified and discussed. The spatial interpolation maps for various geochemical parameters were generated using GIS software.