Assessing Hydrological Drought Charactertics: A Case Study in a Sub Basin of Tamil Nadu, India.

Abstract

Assessment of hydrological drought and evaluation of drought characteristics provide useful information for sustainable water resources planning and management in a river basin. In the present study, streamflow drought index (SDI) was used to assess the hydrological drought characteristics in the Parambikulam-Aliyar basin of Tamil Nadu, India by considering streamflow volume as an indicator of drought severity. The temporal behavior of hydrological droughts were analyzed initially and then, frequency of annual drought severity and recurrence patterns of severe drought events was assessed. The temporal analysis of the SDI values indicated that moderate, severe and extreme droughts are common in the Aliyar sub basin and suggested that the basin suffered severe drought during the 1970s, 1980s and 2000s especially in 1972-74, 1982-85, 1987-88 and 2002-04. January followed by June are the months during which hydrological drought occurs most frequently. Frequency analysis of drought severity indicated that the drought that occurred in the 1970s, 1980s and 2000s has an associated return period of about 80 to 100 years. The result of this study can be used as guide to develop drought preparedness plans and formulate mitigation measures within the basin.