Variability of coastal change along the western Yukon Coast

• Main Authors: Konopczak, A. M., Manson, G. K., Couture, N. J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Geological Survey of Canada 2014
• Subjects: Beaufort Sea; Climate change; Yukon
• Online Access: https://epic.awi.de/id/eprint/37115/; https://epic.awi.de/id/eprint/37115/1/Konopczak_et_al_2014_OpenFile_7516.pdf; http://geoscan.nrcan.gc.ca/starweb/geoscan/servlet.starweb?path=geoscan/downloade.web&search1=R=293788; https://hdl.handle.net/10013/epic.48399; https://hdl.handle.net/10013/epic.48399.d001

Because the Yukon coast along the Beaufort Sea has the highest ground ice contents in the Canadian Arctic and, in addition, faces the direction of most effective storms, this section of coast is considered to be highly vulnerable to the effects of climate change. In order to gain insight into the regional coastal dynamics, a quantification of coastal change was undertaken that allowed the determination of spatial and temporal variability of coastal change along a 35 km long section of coast, stretching from Komakuk to the international border. Shorelines from several years between 1951 and 2009 were digitized from georeferenced aerial photographs and an ortho-rectified SPOT image. Shoreline change statistics were subsequently calculated using the Digital Shoreline Analysis System (DSAS) extension for Esri ArcGIS. Theodolite and real-time kinematic GPS data that was collected during several surveys between 1991 and 2012 at two Geological Survey of Canada (GSC) monitoring sites (Border site and Komakuk site) were analysed to provide higher temporal resolution of coastal change for the last two decades. Additionally, the field survey data enabled an assessment to be made of the contribution of geomorphic variables (i.e. beach slope, beach width, cliff slope, absolute cliff height, relative cliff height) towards explaining changes of coastal erosion. According to the findings, the mean annual erosion along the western Yukon coast has been -1.2 ± 0.4 m/a over the entire period of study, with the rates decreasing through time from -1.4 ± 0.6 m/a between 1951 and 1972, to -1.2 ± 0.5 m/a between 1972 and 2009. However, site specific investigations show that there are differences in the mean erosion rates and in temporal trends. To the west at the Border site, the mean annual erosion rate is -1.3 ± 0.3 m/a, and the rates have recently accelerated, while at Komakuk in the east of the study area, the mean annual erosion rate is -0.9 ± 0.2 m/a, with the rates decelerating over time. A comparison of these findings to erosion ...