Project Description: Flow regime is of central importance in sustaining the ecological integrity of flowing water systems and can be considered a “master variable” that limits the distribution and abundance of riverine species. The five components of the flow regime; magnitude, frequency, duration, timing, and rate of change, are linked to many critical physicochemical characteristics of rivers, such as water temperature, channel geomorphology, and habitat diversity. Alteration of flow thus has cascading effects on the ecological integrity of rivers.

We generated flow metrics using Hydrologic Index Tool (USGS) from discharge data provided by the Water Survey of Canada for flowing waters in Ontario. A subset of these metrics will be used to group ecologically similar flow regimes using principal components and cluster analyses. Phase two of this project will focus on building models to predict various aspects of the flow regime largely on the basis of landscape-scale factors. These predictive models will then be used to predict flow characteristics in ungauged watersheds in Ontario.

Classifying flow regimes in Ontario will help us understand the fundamental nature of our rivers, aid in understanding changes to flows in settled landscapes and how to restore rivers. This understanding in Ontario is sorely needed as we venture in to licensing hydro-power facilities, developing monitoring and assessments frameworks, and will be a valuable tool for fisheries management in lotic systems.

Collaborators and Participants: US Geologic Survey

Links: Indicators of Hydrologic Alteration, The Natural Flow Regime

Map of Study Area: Province of Ontario

Interesting Facts: Streamflow, quantity and timing, which is strongly correlated with many critical physicochemical characteristics of rivers, such as water temperature, channel geomorphology, and habitat diversity, can be considered a “master variable” that limits the distribution and abundance of riverine species and regulates the ecological integrity of flowing water systems.