Preliminary Design of a Landfill and Revetment on Bikini Island, Republic of the Marshall Islands

摘要

Topsoil on Bikini Island, which is located 2,500 miles southwest of Hawaii at 113 deg 35 min N, 165 deg 25 min E, was contaminated by radioactive fallout from nuclear weapons tests in the late 1940's and early 1950's. The uptake of this radioactive fallout, primarily cesium-137 in plants, has prevented resettlement of the island by the native population. One alternative solution proposed by the congressionally appointed Bikini Atoll Rehabilitation Committee involves removal of the contaminated topsoil and placement of the excavated material as a landfill on the 2,500-ft-wide reef flat adjacent to the eastern (windward) shore of the island. This paper explores that alternative by first developing an extremal wave climatology offshore of Bikini Island from 21 years (1959-1979) of typhoon data published by the Joint Typhoon Warning Center on Guam. Deepwater wave conditions just offshore of the reef are estimated and transformed to the point of breaking at the edge of the reef. Storm surge is estimated based on these same parameters. Wave setup on the reef flat is estimated based on the simulated breaking conditions. Given an estimate of the elevated water level across the reef caused by storm surge and wave setup, depth limitations and fractional decay are estimated to define wave conditions at the toe of the proposed revetment. A rubble-mound revetment design stable in these conditions, armored by coral limestone quarried from the reef flat, is then formulated and corresponding material quantities estimated.