COMPARISONS IN GROUNDWATER LEVEL SCENARIO (PRIOR TO REASSESSMENT AND POST ASSESSMENT PERIOD OF GEC) IN OVER-EXPLOITED MANDALS, TELANGANA STATE

Pandith Madhnure, A.B.Kawade, P. Sudhakar, A.D. Rao, P.N.Rao

Abstract: Out of 464 mandals, 42 mandals from Telangana State (~7% of area) have been declared as over-exploited (OE) as per 2011 year of reassessment of Dynamic Groundwater Resources and 1128 villages are notified as per WALTA Act. Geologically the state is underlain by granite/gneisses, limestone, sandstone and basalt and receives annual rainfall between 730 mm to 1120 mm (average 944 mm) and drained mainly by rivers, the Godavari and the Krishna and their tributaries. CGWB monitors about 58 observation wells out of 738 wells in these OE blocks four times a year (January, May, August and November) for water levels and one time for groundwater quality (May). Comparison in groundwater level scenario during the year 2010 (prior to reassessment period) and during 2014 is made as they were the year of excess rainfall of 26% and deficient year of rainfall of 29%. From the study it is concluded that shallow water levels (2.1-21.5 m bgl) are observed during pre-monsoon season (May) of 2014 as compared to pre-monsoon of 2010 (4.3 to 22.3 mbgl). Due to less rainfall in 2014, deeper water levels are observed during post-monsoon season (November) of 2014 (2.1 to 25.8 m bgl) as compared to 2010 season (0.86 to 11.92 mbgl) and number of wells showing deeper water levels increased during this period. Decadal mean of water levels during pre and post-monsoon season of 2004-2014 (4.04 to 26.07 & 1.95-17.7 mbgl), is at deeper levels as compared to the 2001-2010 (4.96 to 18.71 mbgl and 1.98-9.11 mbgl) and there is increase in number of wells showing deeper water levels during the period.

Keywords: Groundwater, Over-exploited, Pre-monsoon, Post-monsoon, Decadal, Scenario.

DOI: https://doi.org/10.15623/ijret.2015.0423010