Evaluation of groundwater quality for irrigation purpose in attur taluk, Salem, Tamilnadu, India
The area in Salem district, Tamilnadu, India is selected to discuss about the impact of groundwater quality on irrigation purpose, where the agriculture is the main business of rural peoples. Granite gneisses associated with schists and charnockites of the Precambrian Eastern Ghats rich in the study area. Groundwater samples collected in pre-monsoon season, from thirtybore wells in the area were analyzed for pH, EC, TDS, TA, TH, Ca2+, Mg2+, Na+, K+, CO32-, HCO3−, Cl−, SO42-. The chemical relationships in Piper's diagram suggest that the groundwater mainly belong to Ca-Mg-Cl, Ca-Mg-SO4 and Non-Carbonate Alkali Type group, are controlled by greater water– rock interaction. Based on the analytical results, chemical indices like Percent Sodium, Sodium Adsorption Ratio, Residual Sodium Carbonate, Permeability Index (PI) Magnesium Ratio and Kelly Ratio were calculated. Residual sodium carbonate values discovered that one sample isnot appropriate for irrigation functions due the incidence of alkaline white patches and low porosity of the soil. PI values are represented in Doneen diagram and revealed that the ground waters are generally suitable for irrigation. USSL and Wilcox diagrams used for assess the water quality for irrigation suggest that the majority of the samples are good for agriculture purpose. Groundwater in the study area is weathering-dominated, and mineral weathering (carbonate and sulphate minerals) and Ion exchange are the most important factors controlling groundwater chemistry.
Groundwater Quality, Irrigation Purpose, Permeability Index, Piper Diagram, Sodium Absorption Ratio.