The Ofu Coastal Storm Damage Reduction, Section 14 study is located on Ofu Island, approximately 66 miles east of the island of Tutuila, American Samoa. It was authorized under Section 14 of the Flood Control Act of 1946, as amended. The American Samoa Government, represented by the Department of Port Administration, is the local non-federal sponsor. A feasibility cost sharing agreement (FCSA) was executed on 11 March 2023, initiating the feasibility study.
The study area is located along the west bank of Ofu Airport’s runway 8/26. The low-lying coastline fronting Ofu Airport is subject to frequent storm and wave attack. The west end of the runway is progressively eroding with the shoreline receding further into the airport’s runway safety area. This coastline erosion was accelerated during Tropical Storm Evans in 2012 and again by Tropical Storm Gita in 2018. Similarly, in July 2022 an extratropical storm that coincided with a king tide resulted in similar impacts to the runway with wave runup, erosion, and damage to the runway. Future sea level rise will continue to exacerbate this condition and cause erosion and resulting damage to accelerate. Without emergency shoreline protection, the runway will continue to sustain damage during high wave and storm events, leading to the imminent closure of the runway and airport operations.
The Tentatively Selected Plan (TSP) consists of a 500 linear ft. tribar revetment. The structure consists of compacted fill as the foundation and base grade, a geotextile filter fabric, a double layer of underlayer stone, and a single layer of 1-ton concrete tribar units. At a horizontal to vertical slope of 1.5 to 1, the revetment is expected to be 33 ft. wide with a crest elevation of 10 ft. above mean sea level. The TSP has a preliminary cost estimate of $8.2 million.