Forecasting Erosion Near Infrastructure in Rural Alaska Communities

Abstract:

Many Alaska communities located along coastlines and rivers are vulnerable to erosion and face mitigation decisions such as protection-in-place, managed retreat, and relocation. To aid these decisions, The Alaska Division of Geological & Geophysical Surveys (DGGS) developed a geospatial tool: Infrastructure Management Planning Assistance for Coastal Towns (IMPACT). IMPACT uses historical shoreline change trends to forecast erosion 50 years into the future (from 2015-2019 depending on the most recent aerial imagery available for the analysis). Shorelines were delineated by DGGS and the U.S. Geological Survey. IMPACT calculates when future shorelines will intersect infrastructure. Infrastructure data files include buildings, power, water, wastewater, and transportation facilities. The results are displayed in community-specific maps and tables, which provide an ideal format for erosion planning. The maps show past shorelines, forecasted erosion areas, locations of safe and at-risk infrastructure, and estimated erosion impact dates. The IMPACT analysis can identify the safer and at-risk locations, estimate impact deadlines of specific infrastructure, and ultimately aid community planners in prioritizing mitigation strategies. This analysis will be completed for approximately 40 communities in western and northern Alaska.