WATER CYCLE EVOLUTION: GROUNDWATER AND STREAMFLOW RESPONSE TO EXTREME PRECIPITATION AND DRYING SOILS IN THE NORTHEAST U.S

Climate change, land-use shifts, and urbanization are redistributing moisture globally, significantly altering hydrological processes. In the Northeast United States, there has been a large increase in the magnitude and frequency of extreme precipitation events coupled with increasing evaporation and decreasing soil moisture. Collectively, these factors are reshaping the annual water budget, with critical implications for ecosystems, water supplies, flooding, and susceptibility to pests and disease.

In Massachusetts, while the water table has been rising, soil moisture levels have decreased, promoting more rapid movement of water through the root zone to deep percolation. This study utilizes high-resolution data from monitoring wells in surficial and bedrock aquifers across the Northeast U.S. to examine the temporal relationship between groundwater levels and precipitation inputs, and to assess how groundwater responses have evolved in response to both drying soils and increased precipitation. Additionally, we compare groundwater level response with streamflow event dynamics at nearby USGS gages, and investigate baseflow anomalies across a catchment scale gradient. We observe that water levels are responding more quickly to precipitation inputs, suggesting that water is moving more rapidly through the root zone. Furthermore, we identify an increasing trend in baseflow in larger catchments, but not in smaller, headwater catchments. Increased recharge in headwaters is contributing to more baseflow in higher order streams.