Groundwater is a dynamic resource as it varies temporally as well as spatially. In order to ensure its sustainable use, ground water assessment, development and management have become essential. The present study attempts to identify and delineate groundwater potential zones in using relevant data, estimation of groundwater and the fluctuation of groundwater levels. In order to delineate the groundwater potential zones, Analytical Hierarchy Process (AHP) and relative importance based weight-rating system have been used. Results of groundwater potential zonation indicate that very high potential zones (16.87 %) are flood plains and inter-hill valley regions with low elevation (<100m). The low (14.35%) and very low (6.24%) potential zones comprise high degree slopes (>30⁰), structural hill ranges and act as run-off generating zones.

Estimation of groundwater resources in Dhalai District were computed according to GEC’97 methodology. In GEC’97 methodology, water level fluctuation method (WLFM) and rainfall infiltration method (RIFM) were used to calculate the amount of recharge from monsoon rainfall.

Monsoon and non-monsoon rainfall recharge shows that the former accounts for 65% and latter accounts for 35% of total rainfall recharge. The pre-monsoon depth to water level data (2011) of the Groundwater Monitoring Stations (GWMS) of Dhalai District show that the water levels vary from 3.03 to 5.47mbgl** and the average pre-monsoon water level of Dhalai District is 4.49m bgl. The water level fluctuation ranges from 0.8m to 4m with the average fluctuation of 2.46m in the District.

References

Groundwater Resource Estimation Methodology (GEC) 1997, ‘Report of the Groundwater Resource Estimation Committee’, Ministry of Water Resources, Government of India, New Delhi.