Water quality studies of groundwater in the proximity of River Noyyal, Tiruppur, South India

In this study, the level of penetration of polluted riverwater on the adjoining aquifers were carried out. Various tools such as Sodium Absorption Ratio (SAR), Wilcox diagram, United States Salinity Laboratory (USSL) and Geographical Information System (GIS) were used to evaluate the quality of water and its suitability for various consumption purposes. Results of SAR show that many of the wells during premonsoon illustrate high values indicating the unsuitable nature of groundwater for irrigation but during postmonsoon, SAR values found to be decreased due to the dilution effect of precipitation by monsoon. Wells belonging to the 1st layer demonstrates very high SAR value and the subsequent layers show diminished values indicating the effect of percolation is not significant as the distance increases. Similar results were found in the case of Wilcox diagram which also substantiates the results of SAR that the wells pertaining to the 1st layer is not suitable for irrigation whereas the 2^nd layer wells display permissible to doubtful reflecting that some of the wells may be used for irrigation. USSL and Wilcox result clearly state that the wells belonging to the 3^rd to Sth layer are suitable for irrigation. Spatial distribution diagram using GIS illustrate that the fIrst zone belonging to the 1^st layer is highly affected and the last zone (Sth zone) is the least affected with regard to the percolation of the polluted water from River NoyyaI. Overlay map shows that the wells falling in the northern part of River Noyyal are less polluted compared to the wells in the southern part.