ABSTRACT: Water level impacts on erosion and flooding along the St. Lawrence River.

CGRG Bibliography of Canadian Geomorphology
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Abstract

Environment Canada (EC) and Pacific International Engineering Corp. (PI Engineering) have been contracted by the International Joint Commission (IJC) to study erosion and flooding processes along the St. Lawrence River downstream of the Moses-Saunders Power Dam as part of the IJC's review of the regulation of flows and levels in the Lake Ontario - St. Lawrence River system. This lower portion of the St. Lawrence is characterized by highly erodible marine clay banks interspersed with sheltered wetlands. Hydrodynamics in the area are dominated by river flow and the effects of ship traffic. This paper presents an overview of the study, including such key issues as: databases that provide inputs to the modeling process, the computational models being used for prediction of erosive forces (currents, waves, ship wakes, etc.), techniques for predicting shore response to different water level regulation scenarios and for predicting shore erosion due to ship traffic. The study has included the collection of bathymetric, LIDAR and recession data along the entire reach of the river. Landside data has been collected to permit the quantification of flood damages in economic terms. Detailed river flow modeling has been conducted by EC using a 2-D steady state finite element flow model. Computational models include ship wake models and a one-dimensional cohesive profile erosion model to predict the response of river banks to flow, wind waves and ship waves. The study of the evolution of the clay shores of the river, along with the numerical modeling tools are providing new insights into the processes that affect and control the erosion of consolidated marine clays.

Bibliography of Canadian Geomorphology