Climatic Water Balance Study and Drought Assessment in Kallar Watershed, Tamil Nadu, India

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.