Exploring variations in concentration-discharge relationships across watersheds in Ontario

Session: Great Lakes Tributaries: Connecting Land and Lakes (2)

Georgina Kaltenecker, University of Toronto Scarborough, [email protected]
George Arhonditsis, University of Toronto Scarborough, [email protected]
Carl Mitchell, University of Toronto Scarborough, [email protected]

Abstract

Chemical concentrations in tributaries often exhibit strong relationships with stream flow.  The nature of this relationship is modulated by factors such as watershed physiography, land use patterns, antecedent conditions, as well as the type of chemical considered.  Understanding the nature of this relationship is critical for gaining mechanistic insights into the factors that contribute to the mobilization and transport of chemicals to tributaries. In this study, concentration-discharge relationships are analyzed using long-term stream water quality and quantity records in Ontario along a gradient of watershed characteristics. We hypothesize that sediment-bound nutrients will exhibit a positive relationship with stream flow, while solutes will demonstrate chemostatic behavior (i.e., apparent stability of concentrations relative to flow variability).  Designed to advance our understanding of the interplay between catchment hydrological behaviour and watershed characteristics, the lessons learned from our study will be critical in establishing an overarching flow-concentration paradigm.