slr_cstl_erosn_line_1_pt_1_ft_NAD83HARN
Type Shapefile
Summary
This data is a portion of a larger project to compile shoreline change data and model future shoreline change of the islands of Kauai, Oahu, and Maui. Sandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline positions and to quantify shoreline change through time.
Description
The erosion hazard line is a spatial depiction of the landward extent of the erosion hazard zone, lands falling within a zone with a certain likelihood (80%) of exposure to erosion, according to probabilistic modeling. This erosion hazard zone is a spatial depiction of lands that are estimated to be vulnerable to erosion by the specified year. The hazard zone is not meant to be a prediction of the exact lands that will be eroded in the future, nor is it a specific prediction of where the shoreline will be in the future. The erosion hazard line includes portions of shoreline where the 80th percentile probability (hazard line) falls seaward of the modern vegetation line, representing possible beach growth.
Future coastal change is projected following Anderson et al. (2015), in which historical shoreline trends are combined with projected accelerations in sea level rise (IPCC RCP 8.5). At each transect location (spaced 20 m apart), the 80th percentile of the projected vegetation line (higher percentiles are more landward) is used as the inland extent of the projected erosion hazard zone for the specified year. This inland extent is connected with the coastline (zero-elevation contour, mean sea level) to create polygons depicting erosion hazard zones.
The projected shoreline change rate is the estimated long-term trend for the shoreline that is likely located somewhere within the hazard zone (unless the shoreline has high rates of historical advance). The exact location of a future shoreline, however, is not shown within an erosion hazard zone.
Prior versions of the erosion hazard polylines were transformed (reprojected) incorrectly into the NAD83(HARN) datum. This update, dated June, 2023 represents files correctly transformed into the NAD83(HARN) datum. Metadata was modified to describe the polyline layers and to reference the University of Hawaii School of Ocean and Earth Science Climate Research Collaborative (CRC) as the data source for the layers, replacing older references to the UH SOEST Coastal Geology Group. This represents a subversion release: no modeling was performed to provide or change future hazard zone or line positions or extents.
This product/data is funded in part by the Hawaii Office of Planning, Coastal Zone Management Program, pursuant to National Oceanic and Atmospheric Administration Award No. NA17NOS4190171, funded in part by the Coastal Zone Management Act of 1972, as amended, administered by the Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, United States Department of Commerce. These data and related items of information have not been formally disseminated by NOAA, and do not represent any agency determination, view, or policy.
Credits
University of Hawaiʻi at Mānoa Climate Resilience Collaborative (CRC) School of Ocean and Earth Science and Technology Coastal Zone Management Program (CZM) National Oceanic and Atmospheric Administration (NOAA)
Use limitations
There are no access and use limitations for this item.
Extent
| West | -159.788519 | East | -159.292754 |
| North | 22.229659 | South | 21.871548 |
Scale Range
| Maximum (zoomed in) | 1:5,000 |
| Minimum (zoomed out) | 1:150,000,000 |