International Journal of Earth Sciences and Engineering

G. Kumar ¹, D. Srinivasan ²

Affiliations
1 Department of Civil Engineering, Vel Tech Dr. RR & Dr. SR Technical University, Chennai-62, IN
2 Department of Geology, National College, Trichy-1, IN

Abstract

The increasing demand for water has brought immense pressure on groundwater resources in the regions where groundwater is prime source. In the present study an attempt has been made to evaluate groundwater potential index (GWPI) for understanding the hydro geological condition of Kallar Watershed, South India. Vertical Electrical Sounding (VES) was carried out at 17 locations within and around the study area. The interpretation of the data obtained from the VES revealed that three non-aquifer geo-electrical layers overlie the un-fractured basement. The first layer has an average thickness of about 0.5 m and resistivity of 83 Ohm-m. The thickness of the second layer is about 0.7 m and resistivity of 438 Ohm-m. The third layer is about 3.4 m thick and has resistivity of about 63 Ohm-m. Aquifer resistivity and thickness interpreted from VES data is used to generate the corresponding thematic maps. Weights are assigned to different ranges of resistivity and thickness values based on their position on geological map. Finally the weighted maps are integrated using a GIS based aggregation method to evaluate the groundwater potential index of the area.

Keywords

Geology, Electrical Resistivity, GIS, GWPI, Thematic Maps, Geological Map, Aggregation Method.

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G. Kumar ¹, D. Srinivasan ²

Affiliations
1 Department of Civil Engineering, Vel Tech Dr. RR & Dr. SR Technical University, Chennai-62, Tamil Nadu, IN
2 Department of Geology, National College, Trichy-1, IN

Abstract

Water is vital importance and throughout history it has been considered as natural resource critical to human survival. Water balance study of a Watershed is an important parameter to understand hydrology, on the basis of which development of water resources of a watershed for various beneficial uses. In the present study, the climatic water balance study and drought assessment was carried out in Kallar watershed, Tamil Nadu, India. Precipitation, temperature and water holding capacity data are the three primary parameters used in this study. Four secondary water balance components namely, potential evapotranspiration, actual evapotranspiration, water deficit and water surplus were derived from the primary parameters. Four water balance indices namely index of aridity; index of humidity, index of moisture and index of moisture adequacy were calculated from secondary water balance components. From the derived indices, drought condition, climatic shift and agricultural potentiality were assessed. In Venbavoor station, 16 out of 32 years witnessed severe to disastrous drought conditions. Similarly, the moisture index percentages show semi-arid to arid climatic condition. The comparison of the present agricultural practices with the results of water balance indices indicates that there is an extensive groundwater mining in the study area.

Keywords

Water Balance, Drought, Kallar Watershed, India.

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