Nearshore sediment transport as influenced by changing sea ice, north shore of Prince Edward Island, Canada

Abstract

This study considers the influence of changing sea ice on nearshore sediment transport in the central north shore of Prince Edward Island, Southern Gulf of St. Lawrence. It is widely accepted that changing climate is causing sea ice to decrease in the region. Sea ice attenuates wave energy thereby reducing sediment transport. The Delft3D hydrodynamic model is used to simulate waves, currents, and sediment transport in seven sea ice concentration scenarios that can be dif-ferentiated into four classes: open water (<10%), low ice (10% to 35%), moderate ice (36% to 60%), and high ice (>60%). If ice concentration decreases from high to moderate, sediment transport is expected to increase 23%. Similarly, if ice concentration decreases from moderate to low, sediment transport is expected to increase a further 24%. If ice concentration decreases from low to open water conditions, sediment transport is expected to abruptly increase a further 85%. The increase in sediment transport as sea ice decreases from high concentration to open water conditions is 180%. Linear and power-law fits of sediment transport and sea ice concentration intersect at an ice concentration of 30%, indicating this value may be a useful threshold in planning for increased coastal erosion and developing appropriate adaptation strategies, in particular, adapting to increased sediment transport near tidal inlets and navigation channels.