Two-dimensional modeling of the Red River Floodway

Abstract

The flood protection works (Shellmouth Reservoir, Portage Diversion and the Red River Floodway) were designed to protect the City of Winnipeg from a flood event with a peak discharge of 169,000 cfs. The Red River Floodway is the component of the flood control works system with the greatest capacity and the one offering immediate flood relief to the City from the Red River floodwaters. After the flood of 1997 the adequacy of the floodway to provide protection against a larger flood event became questionable. The role the floodway plays in providing flood protection to the City of Winnipeg cannot be emphasized enough. The safety of the City depends on the adequate and reliable performance of this channel. A numerical model of the floodway channel has been established using the one-dimensional HEC-RAS and the two-dimensional FESWMS programs. The models were calibrated using water level measurements collected during the 1997 flood. The calibrated models were then used to evaluate the performance of the floodwaychannel under high flow conditions. Of particular interest were the flow corresponding to the maximum design discharge of the channel (Q = 100,000 cfs) and the flow associated with an 1826 flood event. (Abstract s ortened by UMI.)