Geospatial Analysis of Recharge of Groundwater and Irrigation Draft from Different Aquifer Systems of Rajasthan, India

Abstract

Groundwater over-exploitation for agricultural crops caused adverse impact on the sustainability of the resources of Rajasthan. Western arid to central semi-arid regions of the state shows a large spital variation in annual rainfall. The study of groundwater elevation zones during pre-monsoon, post-monsoon, and post winter irrigation (January to March) seasons shows a steady declining of groundwater level of places such as Osian (1.93 m/year) and Piprali (1.50 m/year) which is attributed to excessive groundwater draft due to irrigation in Rabi season. It has been predicted that most of the tube wells in Osian and Piprali may get dry completely by 2048 and 2068, respectively. However, during the same period Khamnor area shows rise in groundwater level at the rate of 1.19 m/year. This variation in groundwater level is attributed to the nature of different aquifer systems viz. alluvium in Piprali, sandstone in Osian, and gneisses in Khamnor area. Implementation of water harvesting structures shows significant improvement in recharge of groundwater in Osian and Khamnor area underlain by hard rock aquifer system. Geospatial analysis of recharge and draft from groundwater during 2008–2009, 2010–2011, and 2011–2012 shows significant changes due to rise and fall in groundwater levels. Over-exploitation of groundwater has developed a non-equilibrium stage between recharge and irrigation draft. In contrary, a positive impact on groundwater recharge in Khamnor area is evident due to higher rainfall and hard rock aquifer with secondary porosity (joints/fractures). Unless preventive measures are taken, the gap between groundwater recharge and draft will increase many folds in future.