Vol. 1, Issue 9 (2016)
Evaluation of groundwater eminence and its appropriateness for drinking and Agricultural use in the hard rock train of Tiruchirappalli Taluk, Tamil Nadu
Author(s): Anandhan P, Chidambaram S, Manivannan R, Ganesh N
Abstract: During the last several decades, human economic activities, especially agriculture and industry have set a trend of consuming ever increasing amounts of fresh water. The regions like Tiruchirappalli district, has a higher density of population to be supported with water. Nearly greater than 50% of the day to day need of the people in this taluk including domestic, industrial, agricultural and partly drinking purpose is met by the groundwater resources only The increase of human population and the economic activities in the region grow in scale; the demand for large supplies of fresh water from various competing and users has increased. There are failures in monsoon and the rivers of this region are ephemeral. In this scenario number deep aquifers have been bored and heavily extracted, increasing the fragility of the system. Surface water present in the tank is also made use of during the rainy periods. This study has made a systematic approach to get an idea about hydrogeochemistry of the groundwater present in the area. To attain a panacea for water chemistry, ground water samples were collected in the Premonsoon seasons. A total of 20 groundwater samples were collected in this season and analyzed for 14 different water quality parameters and the result indicates, that higher EC and TDS values are observed in this region. The analytical precision for the measurement of major ions is about ±6% to ±9%. The total cations (TZ+) and total anions (TZ") balance (Allan Freeze and Cherry 1979) shows the charge balance error (E %) percentage. The error percentage is between ±2% to ±10%. The correlation coefficient between TZ+ and TZ~ is generally occurring around 0.6 to 0.9. TDS/EC ratio ranges from 0.5 to 0.8. In the season HCO3 + Cl dominates the anions, with few representations for SO4. In both seasons Na+ K are the dominant ions. Bicarbonates derived from silicate mineral weathering are noted in the SW and Southern region. The electrical conductivity (EC) value varies from 369.37 µs/cm2 to 4109.10 us/cm2. On an average 1522.04 µs/cm2 is observed in the region. As per Sodium Adsorption Ratio values 50% of the samples are suitable for irrigation. The Residual Sodium Carbonate indicates 60% of the samples fall in safe and 40% of the samples fall in unsafe zones and prolonged usage of this water will affect the crop yield. The Permeability Index of the groundwater indicates groundwater from the study area is moderate to good for irrigation purposes. Thermodynamic studies reveal that groundwater of the region are stable with Kaolinite stability field in all the silicate systems. Comparison of water quality to standards shows that the water can be used for drinking and for irrigation purposes except in few locations.