Forecasting groundwater resources for future sustainability: a geospatial approach in the Himalayan Beas basin

Groundwater constitutes approximately 30% of the world's freshwater, making it an essential natural resource for all living beings. However, unplanned usage has resulted in the depletion of groundwater levels, necessitating sustainable management practices. Traditional field mapping of groundwater availability (GWA) is expensive and time-intensive, posing challenges to its effective management. This study proposes a simple methodology to predict the future groundwater availability using remote sensing and Geographical Information Systems (GIS) tools. Ten thematic layers depicting various basin characteristics including annual average rainfall for the year 2012 to 2021 were used to predict groundwater availability zones map for the year 2022 in the Beas river basin. Relative influence of each layer was computed using analytical hierarchy process with consistency ratio below 0.1. The results showed comprehensible dependence of groundwater availability over rainfall, being the prime source of groundwater recharge. The predicted GWA map showed higher groundwater availability in the western part of the basin due to higher rainfall, porous lithology, mild slope, lower drainage density and curvature as compared to the eastern part which consisted of the lower Himalayan region. The results were validated based on actual groundwater data yielding fairly accurate predictions with only 3 out of 35 stations not agreeing to the prediction. The predicted groundwater availability zones map outlines the areas with readily available groundwater in future and recommends the areas for groundwater recharge optimizing water management, aiding in drought preparedness, resource allocation, infrastructure planning, and environmental protection, ensuring sustainable usage and resilience to climate change.