Community-scale Coastal Vulnerability Mapping in Alaska: Status and Needs

Abstract:

Alaska’s extensive shorelines are incompletely mapped and under-instrumented to proceed with widespread assessments of coastal vulnerability. Despite this baseline data shortage, many of Alaska’s coastal communities are involved in mitigation or adaptation efforts in response to natural hazards such as erosion and flooding. To provide coastal communities with the tools that are necessary to support local decision-making, the Alaska Division of Geological & Geophysical Surveys (DGGS) has undertaken focused field studies to improve quality, quantity and access to coastal datasets such as topography, nearshore bathymetry, rates of shoreline change and relevant water levels. These efforts are inclusive of both standard approaches (e.g. lidar, repeat coastal profile measurements, Digital Shoreline Analysis System assessments and fully-instrumented tide stations) as well as alternative methodologies that improve our ability to economically accomplish this work in harsh, remote areas (e.g. Structure From Motion surface models, quantification of local knowledge observations, stop-gap tidal datum conversion tools, and pressure-sensor water level networks). We present a comprehensive summary of the geographic variability of coastal dynamics and geohazard potential along the Alaska shoreline, from the erosion-prone North Slope coastline to low-lying areas in western Alaska that are at elevated risk to storm surge inundation. This work provides a graphical summary of the existing quality and spatial extent of data in Alaskan coastal communities while highlighting critical data gaps, such as high-precision elevation models, which are delaying more robust flood and erosion vulnerability mapping. By outlining ongoing work and providing examples from recent DGGS projects we will showcase some of the new vulnerability mapping tools under development for our state and also identify opportunities for necessary collaborations in the Alaska coastal zone.