Assessment of Groundwater Quality using GIS Techniques in Vaniyar Watershed, Ponnaiyar River, Tamil Nadu

Abstract

Water quality assessment is essential to ensure viable safe use of the resources for drinking, agricultural, and industrial purposes. Sixty groundwater samples were collected systematically during pre and post monsoon season in the Vaniyar watershed in the Dharmapuri district, Tamil Nadu. Understand the geochemistry of the groundwater and to assess the overall physicochemical faces in the study area. Vaniyar watershed lies between the latitudes 11°46’ N to 12°09’39” N and longitudes 78°12’27” E to 78°36’65” E and covering an area of 982.25 km2. Out of which plain land covers an area of 591.43 km2. The study area is underlain by the Archaean crystalline rocks surrounded by hills. The physical and chemical parameters of the analytical results of groundwater were compared with the standard guideline of values recommended by the Bureau of Indian Standards (BIS) and World Health Organization (WHO) standards for irrigational suitability, domestic usage further hydrogeochemical data have been plotted in a standard graphs such as United State Salinity Laboratory (USSL) and Wilcox's diagrams. Based on the United State Salinity Laboratory (USSL) results of C3-S1 (452.75 Km2) class is good and could be used for all types of crops. Base on the Wilcox's diagrams that the groundwater near the downstream is good for irrigation and the contamination are found to be high in some places. This may be due to the rock water interactions because highly weathered rock noticed during field validation. Result reveals that 377.41 Km2 (61.67%) areas fall in (Wilcox) Good to Permissible category and 452.75 Km2 area falls in (USSL) C3-S1 category. Above said areas indicate that the groundwater could be used for all types of crops. According to U.S. Salinity Laboratory diagram, the majority of groundwater samples belongs to C3–S1 (High Salinity – Low SAR) category and spatially covers an area 452.75 Km2 under “Suitable” zone. In the present study, it is evident that high salinity of groundwater persists at majority of sites. Hence, for high to very high salinity of waters, soil must be permeable with adequate drainage facilities for satisfactory crop growth.