ABSTRACT
Quaternary glacial deposits underlie Eastern Canada. Rivers incised in till and clay deposits can erode rapidly in high flows. Regions within the St-Lawrence Lowlands having land use change resulting in higher peak discharges can experience greater erosion rates, exacerbated by increased precipitation due to climate change. There is limited knowledge of the complex erosion processes of rivers in tills or of the range of critical shear stresses in either tills or clay deposits, particularly sensitive clays. Based on surficial geology maps and field surveys, representative minimally disturbed samples of clays and tills were collected from streambeds. The Sherbrooke sampler was used to collect clay samples for geotechnical testing and two methods were developed to collect samples for geotechnical and fluvial erosion testing for both clays and tills. The geotechnical properties will later be correlated with the critical shear stresses obtained from flume erosion tests of the samples.
