ASSESSMENT OF GROUNDWATER QUALITY FOR IRRIGATION USE

The availability of groundwater, namely fresh water is too less. This situation provokes the scientific community to further research in the field groundwater exploration of fresh water and natural recharge estimation, which are the most important components essential to formulate dependable groundwater management strategies in scarcity, affected regions. Hydrochemical studies were conducted in Chinnaeru river basin of Nalgonda District, Andhra Pradesh, India. Water samples from 28 locations were collected from bore wells during May 2011 and analyzed for different physico-chemical parameters. Based on various indices and water quality standards, the water is classified for safe drinking and irrigation uses. The concentration of fluoride in groundwater ranges from 0.4-2.9 mg/l. Piper diagram reflect that the water belong to Ca +2 –Mg +2 –HCO3 - to Na + –HCO3 - types. The Wilcox diagram suggests that most of the samples are within the permissible limits which can be used for irrigation. High fluoride content in groundwater can be attributed to the continuous water rock interaction during the process of percolation with fluorite bearing country rocks under arid, low precipitation and high evaporation conditions of the study area. The low calcium content in rocks and soils and the presence of high levels of sodium bicarbonate in soils and waters are important factors favouring high levels of fluoride in waters. The basement rocks provide abundant sources of fluoride in the form of amphibole, biotite, fluorite and apatite. The high fluoride concentration areas are demarcated and de-fluoride plant were installed to treat the water for safe drinking purposes. Index Terms: Groundwater, Bore wells, Wilcox diagram, Piper diagram, Fluoride content.