Groundwater dynamics in a steep Himalayan catchment: the role of a widespread weathering layer in water storage and transfer
Résumé
The Himalayan region is crucial for providing water resources to millions of people in downstream regions across Asia. However, the processes governing groundwater storage and flow in steep mountain catchments remain poorly understood, particularly regarding the interplay between monsoonal rainfall, infiltration, and groundwater recharge in these highly dynamic landscapes. This study investigates the Kahule Khola watershed in central Nepal, combining field-based approaches encompassing Electrical Resistivity Tomography (ERT), infiltration measurements, and hydrogeochemical analyses, to investigate the pathways and storage mechanisms of groundwater across pre-, during, and post-monsoon seasons. Our findings highlight the critical role of a laterally extensive weathering layer, 10–25 m thick, in regulating hydrological processes. The weathering layer exhibits high infiltration capacities (