Groundwater quality appraisal in parts of Dun Valley aquifers in the Terai Region, central Nepal

Abstract

The hydrogeochemical parameters for forty five groundwater samples of the Dun valley aquifers of central Nepal were studied to appraise the major ion chemistry and suitability of groundwater quality for domestic and irrigation uses. Geologically, the area comprises of Quaternary alluvium composed of boulder, cobble, pebble, gravel and sand with intercalation of clays. Geochemical classification of groundwater shows that the majority of groundwater samples belong to the calcium-bicarbonate type. TDS values of groundwater in the study area are <1000 mg/l, therefore all groundwater evaluated are suitable for drinking and irrigation uses. The high nitrate concentration (>50 mg/l) of about 53% of the groundwater samples may be due to the local domestic sewage, leakage of septic tanks, and improper management of sanitary landfills. In general, %Na and SAR values indicate good to permissible use of water for irrigation purposes.