Investigating the nexus of groundwater levels, rainfall and land-use in the Kathmandu Valley, Nepal

Groundwater levels in the Kathmandu Valley, Nepal, exhibit strong seasonal fluctuations directly tied to monsoonal rainfall, with agricultural areas showing significant recharge and built-up zones experiencing limited replenishment due to high extraction and surface sealing. A two-year analysis of 35 citizen-scientist monitored wells revealed groundwater depths ranging from −0.11m (above ground) to 11.5m, averaging 4.24m with a standard deviation of 2.29m. While agricultural land uses demonstrated an 80% strong and statistically significant correlation between rainfall and groundwater levels, non-agricultural areas showed weaker correlations due to anthropogenic factors. Highly permeable sand and gravel zones in northern districts act as consistent recharge sources, whereas less permeable clay and silt areas display greater seasonal variability. The study underscores the potential of citizen-generated hydrogeologic data and emphasizes the critical role of land-use planning in sustaining groundwater resources amid rapid depletion.

Prajapati, R., Upadhyay, S., Talchabhadel, R., Thapa, B. R., Ertis, B., Silwal, P., & Davids, J. C. (2021). Investigating the nexus of groundwater levels, rainfall and land-use in the Kathmandu Valley, Nepal. Groundwater for Sustainable Development, 14, 100584. https://doi.org/10.1016/j.gsd.2021.100584