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TitleFlooding, structural flood control measures, and recent geomorphic research along the Red River, Manitoba, Canada
AuthorBrooks, G R; St. George, S
SourceGeomorphic approaches to integrated floodplain management of lowland fluvial systems in North America and Europe; by Hudson, P F (ed.); Middelkoop, H (ed.); 2015 p. 87-117, 5
Alt SeriesEarth Sciences Sector, Contribution Series 20120319
PublisherSpringer New York
Mediapaper; on-line; digital
File formatpdf
NTS62H/03; 62H/06; 62H/11; 62H/14; 62H/15; 62I/02; 62I/03; 62I/07
AreaRed River; Winnipeg; Lake Winnipeg; Assiniboine River
Lat/Long WENS-97.5000 -96.5000 50.5000 49.0000
Subjectssurficial geology/geomorphology; hydrogeology; flood potential; flood plains; floods; precipitation; alluvial deposits; groundwater regimes; structural analyses; structural controls; geological hazards; Quaternary
Illustrationslocation maps; photographs; plots; tables; flow charts
ProgramPeople Support
Released2015 04 30
AbstractThe Red River, Manitoba, Canada, is a low-gradient, meandering river that traverses the broad, flat Red River Valley on the northeastern portion of the Great Plains of North America. The shallow stream-cut valley occupied by the river has insufficient capacity to contain large discharges, which allows higher magnitude flows to overtop the valley sides and spread up to 40 km across the adjacent clay plain. Major flooding impacts communities and rural areas, including the City of Winnipeg, and has caused significant flood disasters in the nineteenth and twentieth centuries. Since 1950, an array of structural flood control measures has been constructed (and some later upgraded) to mitigate flooding, including two diversion canals, a flood control dam, dyking (linear and ring dyking), and elevated earthen pads under structures. Multidisciplinary research initiated following the 1997 Red River flood provided a geomorphic context to the flood problem in support of decision making towards enhancing the flood-protection infrastructure. Based on flood signatures in the growth rings of bur oak trees (Quercus macrocarpa Michx.), the historic flood-of-record in 1826 is interpreted to be the largest Red River flood since at least 1648. An assessment of the decrease in river gradient arising from regional differential uplift revealed that the broad, shallow flood character is intrinsic to the landscape of the Red River Valley and that the contemporary rate of uplift is causing an insignificant change to the extent of flooding. An investigation of the evolution of the genetic floodplain indicates that fluvial geomorphic processes are not significantly enlarging or infilling the shallow stream-cut valley at rates relevant to altering the modern flood problem. Although flood management along the Red River is heavily dependent on structural measures, the design discharge of the integrated flood control works protecting Winnipeg has recently been enhanced to a 700-year return period, which reduces the flood hazard substantially.