Recent trends and variability in river discharge across northern Canada
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Date
2016-12-08
Authors
Dery, Stephen J.
Stadnyk, Tricia A.
MacDonald, Matthew K.
Gauli-Sharma, Bunu
Journal Title
Journal ISSN
Volume Title
Publisher
Copernicus Publications
Abstract
This study presents an analysis of the observed
inter-annual variability and inter-decadal trends in river discharge
across northern Canada for 1964–2013. The 42 rivers
chosen for this study span a combined gauged area of
5.26 106 km2 and are selected based on data availability
and quality, gauged area and record length. Inter-annual variability
in river discharge is greatest for the eastern Arctic
Ocean (coefficient of variation, CVD16 %) due to the Caniapiscau
River diversion into the La Grande Rivière system
for enhanced hydropower production. Variability is lowest
for the study area as a whole (CVD7 %). Based on the
Mann–Kendall test (MKT), no significant (p > 0.05) trend in
annual discharge from 1964 to 2013 is observed in the Bering
Sea, western Arctic Ocean, western Hudson and James Bay,
and Labrador Sea; for northern Canada as a whole, however,
a statistically significant (p < 0.05) decline of 102.8 km3
25 yr1 in discharge occurs over the first half of the study
period followed by a statistically significant (p < 0.05) increase
of 208.8 km3 25 yr1 in the latter half. Increasing (decreasing)
trends in river discharge to the eastern Hudson and
James Bay (eastern Arctic Ocean) are largely explained by
the Caniapiscau diversion to the La Grande Rivière system.
Strong regional variations in seasonal trends of river discharge
are observed, with overall winter (summer) flows increasing
(decreasing, with the exception of the most recent
decade) partly due to flow regulation and storage for enhanced
hydropower production along the Hudson and James
Bay, the eastern Arctic Ocean and Labrador Sea. Flow regulation
also suppresses the natural variability of river discharge,
particularly during cold seasons.
Description
Keywords
River discharge, Canada
Citation
Déry, S. J., Stadnyk, T. A., MacDonald, M. K., and Gauli-Sharma, B.: Recent trends and variability in river discharge across northern Canada, Hydrol. Earth Syst. Sci., 20, 4801–4818, https://doi.org/10.5194/hess-20-4801-2016, 2016.