ASSESSMENT OF CLIMATIC AND VEGETATION INFLUENCE ON SPATIAL DISTRIBUTION OF GROUNDWATER RECHARGE IN HUMID SUBTROPICAL CENTRAL GANGETIC PLAIN

Abstract

Groundwater Recharge (GR) is a crucial part of sustainability studies since it is one of the key factors responsible for making the groundwater resource renewable. An optimum strategy for responding to water level decline is artificial groundwater recharge. Artificial groundwater recharge projects are limited by cost, and the effective area is less. The role of natural factors for groundwater recharge is well defined and recognized in arid regions, whereas it's challenging for humid areas. The current study's main aim is to understand the contribution of the bio-geophysical aspect to groundwater recharge in the subtropical monsoon state of Uttar Pradesh in the Central Gangetic Plain. However, recharging is also one of the least understood processes because it changes over time and space and is challenging to quantify directly for a larger area. This research applied for the 'water and energy transfer among bare soil, vegetation, and atmosphere (WetSpass)' model to estimate direct natural GR for Uttar Pradesh. The model's output and correlation test and principal component analysis with climate, vegetation, soil type, and slope give a comprehensive understanding of the effect of natural controlling factors. Among the aforementioned controlling factors, though climate sharpens recharge substantially, vegetation is the second most significant component influencing the GR of the state. According to the "trade-off-theory," the paradigm of forest ecology vegetation jeopardizes scarce water resources. But the current study has found locations, where groundwater recharges are dominantly controlled by vegetation cover in the forest, intermediate tree, and grass areas where either role of hydrological and physiographic factors are insignificant or exceed evapotranspiration loss by recharging. In contrast to the prevailing view, vegetation cover can enhance groundwater recharge in the state. Thus, plantation, and various tree management options, including groundwater-feeding species as a secondary plantation in cropland, can improve groundwater resources.