Evaluation of Legacy Forest Harvesting Impacts on Dominant Stream Water Sources and Implications for Water Quality Using End Member Mixing Analysis

Forests are critical water supply regions that increasingly threatened by natural and anthropogenic disturbance. Evaluation of runoff-generating processes within harvested undisturbed headwater catchments provides insight into disturbance impacts on quality drinking treatability. In this study, an extensive hydrologic dataset collected at the experimental Turkey Lakes Watershed (TLW) located Canadian Shield was used to quantify sources stormflow in legacy clear-cut (24-years post harvesting) forested (control) using end member mixing analysis (EMMA) model. Stream water, groundwater, soil throughfall were evaluated during spring snowmelt, stormflow, fall wet-up. Groundwater chemistry similar stream both catchments, suggesting groundwater is a major contributor flow. The small wetlands study comparable chemistry, also important contributors Differences wetland position between control appeared have greater influence source contributions than harvesting. Results from provide runoff-generation reflect event/seasonal flow dynamics quality.