Document Type

Internship Report

Publication Date

Spring 2013

Abstract

Like global mean sea level (GMSL), the local sea level in American Samoa has been rising as far as empirical evidence indicates, and though the instrumental record is limited in the Pacific Island region, the rate of rise, like that of GMSL, also appears to be accelerating. As a result of the steep topography of the main American Samoan islands, the majority of the territory’s population, infrastructure, and arable land are found on low-lying coastal plains, leaving them vulnerable to inundation and increased erosion. As sea level rises, visualization tools can help coastal managers and other decision-makers plan for associated problems including salt-water intrusion of freshwater sources, inundation of valuable land and infrastructure, and loss of habitat. To this end, and as the first part of an effo1t to meet the science needs of the National Marine Sanctuary of American Samoa, a series of passive­-inundation maps depicting incrementally elevated sea levels was produced for 22 selected coastal areas of Tutuila and Aunu’u islands highlighting areas, populations, and infrastructure vulnerable to inundation. The data were then spatially analyzed to quantify land area and land cover types likely to be affected under different inundation scenarios. Of land cover types represented on Tutuila and Aunu’u, wetlands are clearly the most vulnerable, with virtually 100% of estuarine forested and estuarine scrub/shrub wetlands (in their cmTent locations) inundated under a 2 m rise in MSL. Impervious surface and developed open space land types represent a good indication of where development is concentrated on the islands, and these two land classes both show significant inundation percentages (> 10%) under 2 m of SLR.

Comments

Department: MPO

MPS Track: Computational Meteorology and Oceanography

Location: The East-West Center Pacific Regional Integrated Sciences and Assessments

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