Assessment of Groundwater Quality for Drinking and Agricultural Purposes in Vamanapuram River Basin, South Kerala, India

Groundwater quality determination is essential for assessing its suitability for drinking and agricultural purposes. In the present study 104 open well water samples were collected during both pre and postmonsoon seasons to evaluate the groundwater quality of Vamanapuram river basin. Samples were analysed for different physico-chemical parameters such as pH, EC, TDS, salinity, Na⁺, K⁺, TH, Ca²⁺, Mg²⁺, Cl^-, NO₃^-, SO₄^2-, PO₄^3- and HCO₃^{- following standard procedures. The acquired values were compared with BIS standards to recognize their aptness for domestic use. From the Piper plot dominant hydrochemical facies identified is Na-Cl for both seasons. Alkalies (Na and K) exceed alkaline earths (Ca and Mg) and strong acids (Cl and SO₄) exceed weak acid (HCO₃) in both seasons. To determine the suitability of water for agricultural use, chemical indices like sodium adsorption ratio, percent sodium, residual sodium carbonate and permeability index were calculated. RSC and PI have revealed that all samples are safe for irrigation. As per Wilcox's diagram and USSL classification, majority of samples are suitable for irrigation except those from the coastal area of Anchuthengu which is unsuitable for drinking as well as irrigation purpose.}