Current and projected flood exposure for Alaska coastal communities

Area of Science:

• Environmental Science
• Climate Change Adaptation
• Coastal Geomorphology

Background:

• Coastal communities globally face increasing flood hazards exacerbated by climate change and sea level rise.
• Traditional methods like the 100-year floodplain are insufficient for remote areas lacking measured flood data.
• Innovative approaches are needed to accurately estimate flood elevations and assess risks in data-scarce regions.

Purpose of the Study:

• To estimate record flood elevations in Alaskan coastal communities using observation-based methods.
• To compare estimated flood elevations with existing elevation models and infrastructure locations.
• To project future flood exposure under various sea level rise scenarios by 2100.

Main Methods:

• Utilized observation-based methods to estimate record flood elevations in 46 Alaskan communities.
• Compared estimated flood elevations against digital elevation models and infrastructure data.
• Integrated sea level rise projections to assess future flood risk and exposure.

Main Results:

• 22% of structures in analyzed Alaskan communities are located within the estimated record floodplain.
• Projected sea level rise by 2100 could increase structure exposure to 30-37% if locations remain unchanged.
• Flood exposure is currently highest in western Alaska, with northern Alaska projected to experience similar levels by 2100.

Conclusions:

• The study provides a transferable method for assessing current and future coastal flood exposure in data-limited regions.
• Incorporating record flood data enhances hazard planning and coastal flood risk assessment for Alaska.
• Identifying and mapping hazardous zones is crucial for preventing development in floodplains and ensuring long-term community safety.