HYDRODYNAMIC AND MORPHOLOGIC MODELING OF ALTERNATIVE DESIGN SCENARIOS FOR SHIPPAGAN GULLY, NEW BRUNSWICK CANADA

This paper describes a comprehensive study comprising field measurements and numerical modeling of hydrodynamic and sedimentary processes undertaken to help assess alternative engineering measures for promoting and maintaining a stable and safe navigation channel through a dynamic tidal inlet. Shippagan Gully is a dynamic tidal inlet located on the Gulf of St-Lawrence near Le Goulet, New Brunswick, Canada. The tidal lagoon transects the Acadian Peninsula, hence the flows through the inlet are controlled by the tidal phase lag between the two open boundaries. Due to the nature of this phase lag, the ebb flows through Shippagan Gully, which regularly exceed 2 m/s, are typically twice as strong as the flood flows. As a consequence of this imbalance, the hydrodynamic and sedimentary processes at the inlet, and the morphologic features produced by these processes, are strongly dominated by the ebb flows. Over the past decades, shipping activities through Shippagan Gully have been threatened due to sediment deposition along the east side of the inlet which has caused the channel to narrow and shift westward. The objective of the present study was to develop an improved numerical model of the hydrodynamic and sedimentary processes at Shippahan Gully, and then apply the model to assess different engineering interventions for stabilizing the inlet and improving navigation safety