Shoreline Changes and Sediment Redistribution at Palmyra Atoll (Equatorial Pacific Ocean): 1874–Present

• Published in: Journal of coastal research Vol. 25; no. 3; pp. 711 - 722
• Main Authors: Collen, J. D., Garton, D. W., Gardner, J. P. A.
• Format: Journal Article
• Language: English
• Published: Fort Lauderdale Coastal Education and Research Foundation 01.05.2009; Coastal Education and Research Foundation (CERF); Allen Press Inc
• Subjects: Atolls; Beaches; Causeway; Causeways; Channels; Coastal; Coastal accretion; coastal erosion; Coastal zone management; Coasts; Conservation organizations; Construction; Coral reefs; ecological impact; historical charts; Islands; Lagoons; Land; Marine; military construction; Oceans; reef islands; Sediment transport; Sediments; Shoreline protection; Shorelines; Soil erosion; Tidal currents; Water circulation; Wildlife; Wildlife refuges; Wildlife sanctuaries; Wind; ISW, India, Andaman and Nicobar Is., Andaman Is., Barren I; USA; IS, Equatorial Pacific; Canada, British Columbia, Reef I; Syria, Palmyra; PSW, South Atlantic, Falkland Is., New I
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/08-1007.1

Reef islands of Palmyra Atoll in the northern Line Islands, equatorial Pacific Ocean, underwent mainly minor natural changes in shape and size between 1874 and 1940. Many major changes occurred between 1940 and 1945 when military construction created a dredged channel into the lagoon, enlarged several islands, joined most islands around the lagoon system into a continuous roadway, constructed a causeway separating two lagoons, and created several new islands. Overall, land area approximately doubled and land volume approximately trebled during this period, and the construction affected water circulation between reef flats and lagoons. Since 1945, the atoll has been largely uninhabited, construction and most maintenance of the newly-created shoreline has ceased, and coastlines of larger islands have simplified by infilling of bays and erosion of promontories, at net rates of up to 1.8 m/y. Narrower land masses have been broken into multiple smaller arcuate islands with intervening shallow channels. Sediment moves mainly westward along ocean coasts, into lagoons on lagoon coasts, and via tidal currents where causeways have been breached. In the east, Barren Island appeared and began growing from natural causes well before military construction. After purchase by The Nature Conservancy, the atoll was designated a U.S. National Wildlife Refuge in 2001. This protection offers the opportunity to observe coastal processes operating in the absence of the efforts to protect infrastructure typically associated with inhabited atolls.