Long-term trends in mountain groundwater levels in Canada and the United States

Abstract

Mountains are vitally important for global water supply, yet little is known about how mountain groundwater is being impacted by climate change. This research aims to quantify trends in mountain groundwater levels and explore how various climatic, physiographic, and anthropogenic factors affect these trends. We compiled data from 171 wells in Canada and the United States with over 20 years of continuous monthly data. The Mann-Kendall test revealed that 54% of wells exhibited statistically significant trends ( p < 0.05), of which 69% were negative. Western mountain ranges showed stronger trends than eastern ranges. Correlation, factor, and regression analyses identified elevation, average annual air temperature, precipitation, and regional effects as the most significant factors influencing groundwater trends. This research found that mountain groundwater levels are most freqently declining in lower-elevation regions with higher temperatures and lower precipitation, which may have important implications for water supply.