Identification of changes in floods and flood regimes in Canada using a peaks over threshold approach |
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| Authors: | Donald H Burn Paul H Whitfield Mohammed Sharif |
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| Institution: | 1. Civil and Environmental Engineering, University of Waterloo, Waterloo, ON, Canada;2. Centre for Hydrology, University of Saskatchewan, Saskatoon, SK, Canada;3. Department of Earth Science, Simon Fraser University, Burnaby, BC, Canada;4. Environment Canada, Vancouver, BC, Canada;5. Department of Civil Engineering, Jamia Millia Islamia, New Delhi, India |
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| Abstract: | Recent flood events in Canada have led to speculation that changes in flood behaviour are occurring; these changes have often been attributed to climate change. This paper examines flood data for a collection of 132 gauging stations in Canada. All of these watersheds are part of the Canadian Reference Hydrometric Basin Network (RHBN), a group of gauging stations specifically assembled to assist in the identification of the impacts of climate change. The RHBN stations are considered to have good quality data and were screened to avoid the influences of regulation, diversions, or land use change. Daily flow data for each watershed are used to derive a peaks over threshold (POT) dataset. Several measures of flood behaviour are examined based on the POT data, which afford a more in‐depth analysis of flood behaviour than can be obtained using annual maxima data. Analysis is conducted for four time periods ranging from 50 to 80 years in duration; the latter period results in a much smaller number of watersheds that have data for the period. The changes in flood responses of the watersheds are summarized by grouping the watersheds by size (small, medium, and large) and also by hydrologic regime (nival, mixed, and pluvial). The results provide important insights into the nature of the changes that are occurring in flood regimes of Canadian rivers, which include more flood exceedances, reduced maximum flood exceedance magnitudes for snowmelt events, and earlier flood events. Copyright © 2016 John Wiley & Sons, Ltd. |
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| Keywords: | floods climate change flood regimes |
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