Catastrophic flooding from Glacial Lake Wisconsin

摘要: Abstract Glacial Lake Wisconsin was a large proglacial lake that formed along the southern margin of Laurentide Ice Sheet during glaciation. It when ice Green Bay Lobe came into contact with Baraboo Hills in southwestern and blocked south-flowing River. During early glacial recession, dam failed catastrophically drained about week. Despite recognition former likelihood it catastrophically, outflow rates failure have not been previously evaluated. Estimates based on step-backwater modeling indicate peak discharge between 3.6 5.3 × 10 4  m 3 /s lower As an alternate method, we used derived empirical relationship volume for dam-break events. From digital elevation model altered to incorporate isostatic depression, estimated be 87 km just prior breach, suggesting flooding magnitude as high 1.5 × 10 5 at outlet. Adjusting these results downstream flood wave attenuation gives around 4.4 × 10 reach, which closely matches modeling. These estimates from catastrophic ice-marginal lakes improve our understanding processes produced morphology behavior present-day upper Midwest river systems.