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TitleHydrological dynamics in the Winnipeg River basin, Manitoba
AuthorSt. George, S
SourceManitoba Science, Technology, Energy and Mines, Manitoba Geological Survey, Report of Activities 2006, 2006 p. 226-230 (Open Access)
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20060334
PublisherManitoba Geaological Survey
Mediapaper; CD-ROM
File formatpdf
ProvinceManitoba; Ontario
NTS52B; 52C; 52D; 52E; 52F; 52G; 52J; 52O; 62H; 62I; 62P
AreaWinnipeg River Basin; Canada; United States of America
Lat/Long WENS -98.0000 -90.0000 52.0000 47.0000
Subjectshydrogeology; hydroelectric potential; hydroelectric power; hydrodynamics; surface waters
Illustrationslocation maps; graphs
ProgramManitoba Hydro, Funding Program
ProgramManitoba Geological Survey, Funding Program
ProgramPrairie Adaptation Research Collaborative (PARC), Funding Program
ProgramNSERC Natural Sciences and Engineering Research Council of Canada
ProgramEnhancing resilience in a changing climate
AbstractBecause hydrological conditions are the greatest source of risk for hydroelectric production, recent studies describing significant declines in discharge during the 20th century for many Canadian rivers are an understandable cause for concern. The Winnipeg River in northwestern Ontario provides nearly half of the total flow into Lake Winnipeg and the Nelson River, and is the most important component of the hydroelectric system generating power in Manitoba. This study uses a network of long-term discharge gauges to examine the frequency, severity and causes of drought in the basin during the last one hundred years. Extremely low annual flows in the Winnipeg River are the product of widespread reductions in precipitation during the previous summer and autumn, warm temperatures
in spring and summer, and very little runoff delivered by spring snowmelt. These conditions are typically associated with circulation similar to the positive mode of the Pacific-North American (PNA) pattern, which may act to inhibit the formation of cyclones in western North
America and reduce the amount of precipitation received by northwestern Ontario. A strong, positive PNA-like pattern during autumn and winter appears to be required in order for extreme low flows to occur, but positive PNA anomalies do not always lead to low flows. In contrast to trends observed for other Canadian rivers, annual discharge in the Winnipeg River increased by nearly 60% during the 20th century. Nearly all of this change is due to increases in summer and autumn precipitation and higher discharge during winter. Reports of declining flow for many rivers in the adjacent Canadian Prairies have led to serious concern for the future reliability of water supplies, especially because surface water is the primary source of irrigation for local agriculture. The observed trends toward higher flows suggests that the potential threats to water supply faced by the Canadian Prairie provinces over the next few decades will not
include decreasing discharge in the Winnipeg River basin.