Resilience study warns of threats, needs, and gaps in coastal security
Pago Pago, AMERICAN SAMOA — The National Fish and Wildlife Foundation (NFWF) released late last week a “Coastal Resilience Assessment for American Samoa”. The report will help identify areas with the greatest potential to improve wildlife habitat and community resilience to flooding threats in the territory.
The report’s summary notes that American Samoa’s dynamic landscape faces numerous natural hazards ranging from tsunamis and earthquakes to cyclones and flash floods.
Due to the territory’s rugged landscape, relatively little land can be developed, leaving much of the population restricted to low-lying coastal areas where communities are left exposed to threats such as sea level rise and storm surge, it says.
These effects are further compounded by significant land subsidence associated with an 8.1 magnitude earthquake that struck off the coast of American Samoa in 2009, the report points out.
As sea levels rise, the 2009 post-seismic event accelerated these effects, leaving American Samoa to face some of the greatest rates of relative sea level rise in the world, the report points out, adding that the earthquake generated devastating tsunami waves up to 72 feet.
“While the frequency of a tsunami event of this magnitude is low, American Samoa faces other threats associated with heavy rainfall events, tropical cyclones, shoreline erosion, and landslides,” it says.
“Extreme rainfall events are expected to increase in frequency and severity,” said the report citing findings from a study, which are included in the assessment. It explains that heavy rains cause regular flash flooding, leading to sanitary sewer overflows, pump station failure, and blocked roadways.
The report explained that, coastal erosion and flooding can damage infrastructure and roads, and squeeze beach and coastal habitat between the steep mountains and the advancing ocean. Furthermore, rainfall, coastal flooding, and coastal erosion throughout the territory threaten tsunami evacuation routes, coastal roads, and other critical infrastructure.
Tropical cyclones can also cause extreme flooding as was recently seen during 2012 Cyclone Evan and 2018 Tropical Cyclone Gita events.
“In response to projected increases in sea level rise and the frequency of extreme rainfall events, numerous efforts have worked to better understand the threats, needs, gaps, and nature- based approaches that can be applied to build resilience in American Samoa,” NFWF report said.
Recent efforts include the Pacific Islands Regional Climate Assessment for American Samoa report (released this year), Multi-hazard Mitigation Plan for American Samoa, U.S. Army Corps of Engineer’s Tafuna flood risk management study and American Samoa Post-Disaster Watershed Assessment, and efforts to promote green storm water infrastructure (HWG 2019) and understand the relative resilience of coral reef ecosystems in American Samoa, among others.
As American Samoa takes steps to lower its exposure and plan for a more resilient future, resources such as this Coastal Resilience Assessment can equip decision-makers and stakeholders with valuable tools and information to help plan for future flood and storm events.
According to the report, the American Samoa Coastal Resilience Assessment provides a framework for a holistic approach that considers both fish and wildlife habitat and resilience for human communities facing growing flooding threats.
In a news release last Friday, NFWF said the assessment for American Samoa was developed in partnership with NOAA and the University of North Carolina-Asheville’s National Environmental Modeling and Analysis Center (NEMAC), with help from a local advisory committee and stakeholders.
NFWF said the assessment combines information about local flooding threats, human community assets, and fish and wildlife species to identify “Resilience Hubs” -- areas of open space near the densest population centers and critical community infrastructure where valuable natural resources and habitats can provide protection to human populations and critical infrastructure facing the greatest risk of flooding from coastal storms and changing sea levels.
Assessment results are intended to complement ongoing coastal resilience planning efforts, and can be used by community planners, conservation organizations, and others to help make informed decisions about the potential for restoration, conservation, or other resilience-related projects to achieve dual benefits for people and wildlife.
Details of the assessment report both in English and Samoan online at: https://www.nfwf.org/programs/national-coastal-resilience-fund/regional-....
Click on American Samoa link for either English or Samoa version.