Erosion and Flooding—Threats to Coastal Infrastructure in the Arctic: A Case Study from Herschel Island, Yukon Territory, Canada

Abstract

Arctic coastal infrastructure and cultural and archeological sites are increasingly vulnerable to erosion and flooding due to amplified warming of the Arctic, sea level rise, lengthening of open water periods, and a predicted increase in frequency of major storms. Mitigating these hazards necessitates decision-making tools at an appropriate scale. The objectives of this paper are to provide such a tool by assessing potential erosion and flood hazards at Herschel Island, a UNESCO World Heritage candidate site. This study focused on Simpson Point and the adjacent coastal sections because of their archeological, historical, and cultural significance. Shoreline movement was analyzed using the Digital Shoreline Analysis System (DSAS) after digitizing shorelines from 1952, 1970, 2000, and 2011. For purposes of this analysis, the coast was divided in seven coastal reaches (CRs) reflecting different morphologies and/or exposures. Using linear regression rates obtained from these data, projections of shoreline position were made for 20 and 50 years into the future. Flood hazard was assessed using a least cost path analysis based on a high-resolution light detection and ranging (LiDAR) dataset and current Intergovernmental Panel on Climate Change sea level estimates. Widespread erosion characterizes the study area. The rate of shoreline movement in different periods of the study ranges from −5.5 to 2.7 m·a Ice-rich coastal sections most exposed to wave attack exhibited the highest rates of coastal retreat. The geohazard map combines shoreline projections and flood hazard analyses to show that most of the spit area has extreme or very high flood hazard potential, and some buildings are vulnerable to coastal erosion. This study demonstrates that transgressive forcing may provide ample sediment for the expansion of depositional landforms, while growing more susceptible to overwash and flooding.

Archaeological Site Vulnerability Modelling: The Influence of High Impact Storm Events on Models of Shoreline Erosion in the Western Canadian Arctic

“…Suffice it to say however that while there are limitations to this method, the approach does hold merit as a means of producing a generalized model of historical coastal change rates. For examples of similar methods applied in heritage management efforts elsewhere, see also : Radosavljevic et al (2015), Reeder et al (2012) and Robinson et al (2010).…”

Summer rainfall dissolved organic carbon, solute, and sediment fluxes in a small Arctic coastal catchment on Herschel Island (Yukon Territory, Canada)

“…The island's coast is eroding rapidly and numerous retrogressive thaw slumps associated with the presence of ice-rich permafrost occur along the shore (Lantuit and Pollard 2008;Radosavljevic et al 2015). Mass wasting also occurs in the form of active layer detachments, thermal erosion gullies, or solifluction on the island and affects the soil organic carbon (SOC) storage (Obu et al 2017).…”

Relation between planimetric and volumetric measurements of permafrost coast erosion: a case study from Herschel Island, western Canadian Arctic

“…Further increase in coastal retreat rates results in considerably lower sediment release. Transects with these high retreat rates and low sediment release rates are located along coastal stretches with relatively low cliffs (Radosavljevic et al 2016), such as the alluvial fan at Simpsons Point. In contrast, high sediment release occurs where the cliffs are higher and coastline retreat rates are not necessarily high.…”