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State of Alaska Alaska / Natural Resources DNR / Geological & Geophysical Surveys DGGS / Geologic HazardsHazards / Coastal HazardsCoastal

Coastal Community Erosion Assessment

Forecasting exposure of Alaska's infrastructure to erosion

The DGGS Coastal Hazards Program works to map erosion forecasts at Alaska communities. The steps used to make erosion forecasts are:

  1. Map historical (1950s to ~2019) erosion rates (see the shoreline change report)
  2. forecast shorelines 60 years into the future, assuming historical erosion rates continue, and
  3. measure what existing infrastructure are within the erosion forecast zone and by what date.

Results of the analysis are displayed in two different maps and a cost of infrastructure replacement summary table within community reports. The Erosion Forecast Map shows the area around a community forecasted to erode in 20-year intervals. The Erosion Exposure Map highlights which buildings are exposed to erosion in the same 20-year intervals; this map is also zoomed in to areas with erosion impacts. Both maps show past shorelines, forecasted erosion areas, locations of infrastructure at risk to erosion, estimated erosion exposure dates, and erosion forecast uncertainty.

The erosion exposure assessment and maps show vulnerabilities to erosion and are expected to be used to aid community planners in prioritizing mitigation strategies and communicate risk. A summary report and individual community reports are available.

This work is funded by the Denali Commission Village Infrastructure Protection Program through the project "Systematic approach to assessing the vulnerability of Alaska's coastal infrastructure to erosion".

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