WARM SEASON HYDROLOGIC PROCESSES IN A BOREAL FOREST HILLSLOPE AND CATCHMENT, NEWFOUNDLAND

Abstract

Prior investigations into boreal forest ecosystems have examined hydrological processes on plot scales, examining factors such as precipitation, soil characteristics, tree rooting depths, evapotranspiration, infiltration, and groundwater, or on the catchment scale, investigating factors such as stream discharge and water chemistry. In this study, I examine hydrological processes at both plot and catchment scales, with the goal of understanding how rooting depths influence evapotranspiration (ET) and the effects of ET on catchment discharge and water chemistry. Evapotranspiration was found to influence seasonal and diurnal fluctuations in groundwater table, stream discharge, and stream electrical conductivity. Tree rooting depths were shallow, primarily within O and Ae soil horizons, suggesting that these trees intercept infiltrating water, reducing summer groundwater recharge. Stream electrical conductivity increased with cumulative ET. Summer streamflow minima coincided with hillslope groundwater minima. Stream depth and conductivity exhibited similar diurnal patterns, suggesting variations in groundwater contributions and opportunities for future research.