ERTH 2415 Lecture 20: L20 - Red River
27 Mar 2018
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Document Summary
L20: red river, manitoba: red river drainage basin, including the assiniboine river, flat topography. Red river: meandering river, low gradient (~7cm per km, occupies a shallow valley (upto 15m deep, long history of flooding, 1826, 1852, 1950, 1979, 1997, 2006, 2009, 2011. Flood facts: unundated more than 2000km^2, up to 40km wide. Major canadian flood disaster: 28,000 people evacuated, costs in excess of m. Unique characteristics for canadian floods: flood is a flow and not a lake, rise and fall slowly (many weeks, generally cause inundation damage and not erosion damage. Fundamental reasons for flood characteristics: low slope, red river gradient ~ 7cm per km, effects how fast water flows, shallow river valley, flat landscape. Net result: broad, shallow, slow moving floods. Coping with flooding: emergency dyking, flood protection infrastructure (buildings on pads, ring dyked towns. Red river floodway: 48-km long flood diversion channel.
