Examining River Flow Dynamics and Water Quality Hotspots Across Agricultural Watersheds

Abstract

The hydrobiogeochemical processes governing water quantity and quality are highly spatiotemporally variable. Five river locations in the Thames River Watershed were used to assess flow regime characteristics (Study 1), nutrient hotspots (Study 2) and their inter-relation (Synthesis). Study 1 suggested that some sites have low groundwater storage and high runoff generation, leading to river flow memory timescales that are longest in fall and shortest in summer seasons. In Study 2, the majority of criteria evaluated led to the positive identification of some sites as phosphate or nitrate hotspots, especially in wetter-than-normal years. Although water quantity and quality are known to be inter-related, the Study 1 results could not be used quantitatively to predict Study 2 results. However, qualitative relationships were established: this thesis therefore provides insight into dominant water and nutrient flowpaths, which could guide the elaboration in the studied subwatersheds and other similar ones in the Lake Erie Basin.