Assessment of Groundwater Quality for Agricultural Purposes in Lower Part of Noyyal Sub-Basin, Cauvery River, Tamil Nadu, India

Abstract

The present study is an attempt to analyze the suitability of groundwater for irrigation representing from a total area of 1493.98 km2 in lower part of Noyyal sub-basin, Cauvery River, Tamil Nadu and India. The 111 groundwater samples were collected during post monsoon (Nov) 2015 and were analyzed for major cations and anions. The various physio-chemical characteristics includes pH, EC, TDS, Alkalinity, TH, Ca2+, Mg2+, Na+, K+, Fe2+, NH3, NO3−, Cl−, F−and SO42-were analyzed. As per the U.S. Salinity diagram, 77.48% majority of groundwater samples belongs to C3–S1 (High Salinity – Low SAR), For medium to high permeability soil, this type of groundwater should be utilized. In the present study, it is clear that high range of salinity in groundwater persists at majority of sites. Hence, for higher value to very high value of salinity in water, soil must be permeable with adequate drainage facilities for satisfactory crop growth. The Wilcox classification has shown 22.52% of groundwater under Unsuitable” zone. 72.97% of samples are classified as Excellent to Good‘, 4.50% of samples are Doubtful to Unsuitable‘ for irrigational purposes. The 48.65% of the groundwater samples fall in Class – I. It indicates that groundwater is good for irrigation purposes in the post-monsoon season. 20.72% of the samples fall under class – III. The classification of Donnen’s Permeability indicates that it is not suitable for agricultural purposes, and it should be treated properly before utilized for irrigation.