Inundation Exposure Assessment for Majuro Atoll, Republic of the Marshall Islands

Low-lying island environments, such as the Majuro Atoll in the Republic of the Marshall Islands, are particularly vulnerable to inundation (coastal flooding) whether the increased water levels are from episodic events (storm surge, wave run-up, king tides) or from chronic conditions (long term sea-level rise). Land elevation is the primary geophysical variable that determines exposure to inundation in coastal settings. Accordingly, coastal elevation data are a critical input for assessments of inundation exposure and vulnerability. Previous research has demonstrated that the quality of data used for elevation-based assessments must be well understood and applied to properly model potential impacts. The vertical uncertainty of the input elevation data controls to a large extent the increments of water level increase and planning horizons that can be effectively used in an assessment. Recent high-resolution elevation data along the coast exhibit high vertical accuracy, and thus have become indispensable for assessments, whether a simple inundation model is used, or a more sophisticated process-based or probabilistic model is employed. When properly characterized, the vertical accuracy of the high-resolution, high-accuracy elevation data can be used to generate maps and report assessment results with the uncertainty stated in terms of a specific confidence level. This data release includes the results of a quantitative assessment of inundation exposure for Majuro Atoll, including rigorous accounting for the cumulative vertical uncertainty in the input geospatial data (elevation model) and data processing (datum transformations). The project employed a recently produced and validated high-resolution, high-accuracy topobathymetric digital elevation model (TBDEM) covering Majuro Atoll. Areas subject to marine inundation (direct hydrologic connection to the ocean) and low-lying land (no direct hydrologic flowpath to the ocean) were mapped and characterized for different inundation levels.

                                            [
  "010:12"
]
                                        

                                            {
  "fn": "Dean Gesch",
  "@type": "vcard:Contact",
  "hasEmail": "mailto:gesch@usgs.gov"
}
                                        

                                            [
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    "accessURL": "https://doi.org/10.5066/P9K1GD9W",
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                                            [
  "Atoll",
  "Calalin Channel",
  "Central Pacific",
  "Coastal Flooding",
  "Djarrit",
  "Episodic Events",
  "Inundation Vulnerability",
  "King Tides",
  "Laura",
  "Majuro",
  "Majuro Atoll",
  "Pacific Islands",
  "Pacific Ocean",
  "Republic of the Marshall Islands",
  "Sea Level Rise",
  "Topobathymetric Digital Elevation Model (TBDEM)",
  "USGS:5ba9511ee4b08583a5ca09fe",
  "Vertical Uncertainty",
  "boundaries",
  "elevation",
  "geoscientificInformation"
]
                                        

                                            {
  "name": "U.S. Geological Survey",
  "@type": "org:Organization"
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                                            [
  "Geospatial"
]