Erosional properties of the sediments in the Petitcodiac River estuary at Moncton, New Brunswick

Abstract

The Petitcodiac River estuary was modified after the construction of a causeway in 1968 at Moncton, New Brunswick. To address some of the sediment-related issues associated with recent proposed changes to the causeway, it is essential to characterize the sediment properties. Several samples were obtained in 2003 and 2004 at eight sites from the upper 5 km of the existing estuary to determine sediment properties including particle size, bulk density, in situ water content, and organic content. These properties were determined from cores extracted from the field and reconstituted cores prepared in the laboratory. Facilities to evaluate the erosion rates of relatively undisturbed sediment cores from the field were constructed; four box cores were tested in a 10 m flume to determine erosion rates with depth. In most cases, erosion rates increased with an increase in the applied boundary shear stress and were strongly dependent on sediment properties and the depositional history of the bed.Key words: cohesive sediments, sediment transport, local boundary shear stress, erosion rates.