Uncertainties and Challenges in Distribution of Groundwater Recharge in Climate Change Scenario

Groundwater use is of fundamental importance to meet the rapid expanding urban, industrial, and agricultural water requirements throughout the world and also in India. To quantify the distribution of groundwater recharge is a prerequisite for efficient and sustainable groundwater resource management in the arid and semi arid regions. Groundwater recharge in these regions shows variability, as per the assessment carried out by using various methods such as Soil Water Balance (SWB) analysis, Integrated Landscape Hydrology Model (ILHM), Water Table Fluctuations (WTF), Isotopic Tracers methods - Chloride Mass Balance, Carbon-14, etc, WetSpass model, SWATMODFLOW model, Empirical method, Numerical Modelling, etc. The interaction of soil, climate, slope, geology, geomorphology, land use land cover, rainfall, drainage pattern and other methods used for recharge determines the recharge process. The study reveals that the reasons causing this variability are ranging from uncertainties in recharge influencing factors to change in climatic conditions. The study also shows that the uncertainties in distribution of groundwater recharge occur differently in different regions, due to the impact of various factors such as change in climatic conditions, land use, soil types, etc. In conclusion, it can be stated that realistic estimation of recharge depends mainly on identifying prominent features influencing recharge for a certain region and probable flow mechanism for targeted aquifer, multiple dependent models / approaches may be applied for estimation of recharge and output may be compared to actual field conditions.