Regional Analysis of Baseflow Contribution to the Grand River, Ontario, Canada

Tricia Anne Stadnyk, University of Manitoba, Department of Civil Engineering, Winnipeg, MB, Canada, John J Gibson, University of Victoria, Victoria, BC, Canada and Fred J Longstaffe, University of Western Ontario, Dept of Earth Sciences, London, ON, Canada

Contact First Author: Tricia Anne Stadnyk; tricia.stadnyk@ucalgary.ca

Previously Published Material: Journal of Hydrologic Engineering; published in fall 2014

Abstract ID#: 34233

 

English Abstract:
With uncertainty surrounding long-term projection of in-stream flow needs, baseflow estimation is an increasingly important component of hydrology and hydrologic modelling. With several methods available to chose from, it is important to understand the advantages and disadvantages of traditional and newer methods of baseflow recession analysis. Operationally, recursive digital filtering (RDF) techniques are commonly applied; however, questions have been raised about the reliability and parameterization of these methods. A comparison of three baseflow separation methods is performed, including two popular RDFs (HYSEP and BFLOW) and one hydrologic model (WATFLOOD). The methods are applied to two baseflow dominant sub-basins of the Grand River Basin in southern Ontario, Canada. The Eramosa River and Whiteman’s Creek sub-basins are similar in size (236 and 383 km2, respectively) and have similar annual runoff distributions, yet significantly different physiography governing runoff generation. Sub-basin physiographic characteristics result in significant differences in annual baseflow distributions, and stable water isotopes (SWIs) are applied for verification of baseflow contribution. Results are shown to support the application of SWIs for regional hydrograph separation and highlight the need for more efficient, yet physically-based baseflow separation in regions with complex physiography.
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