Hawaii Coastal Erosion Website

The Hawaii Shoreline Study provides shoreline change data to the public and government partners to assist in decision-making in the coastal zone. Shorelines are highly variable environments characterized by a number of natural hazards. These include: tsunami, storm surge, high winds, coastal erosion, sea-level rise, and high wave overtopping. Building on eroding coasts increases vulnerability to all these hazards. A direct step to mitigating the impact of coastal hazards is to exercise avoidance (Hwang, 2005) by mapping high hazard zones designed, in part, on data such as found in this study.

A significant additional benefit to shoreline change data is to define zones of avoidance for the purpose of environmental conservation. When erosion threatens the built environment a common reaction is to armor the shoreline with a seawall or revetment. Armoring may impound sand thereby impacting the sediment budget of a beach and exacerbating the erosion. Shoreline armoring also increases wave turbulence and reflection. It is common to find that the construction of one seawall on a beach leads to proliferation of additional seawalls. Armoring a chronically eroding coast leads to beach loss (Fletcher, et al., 1997). In an era of accelerating sea-level rise (Church and White, 2006) the threat of chronic erosion and beach loss is growing and the use of shoreline data becomes a potentially significant coastal management tool in the effort to conserve beaches for future generations.

This site provides sets of historical maps and air photos, modern vertical and oblique air photos, and maps depicting rates of shoreline change spaced every 20 m on the sandy beaches of Maui, Oahu, and Kauai. Please click on an island to access the database.

References

Church, J. A. and N. J. White., 2006. 20th century acceleration in global sea-level rise, Geophys. Res. Lett., 33 (1), L01602.

(1), L01602. Fletcher, C.H., Mullane, R.A., and Richmond, B.M., 1997. Beach loss along armored shorelines of Oahu, Hawaiian Islands. Journal of Coastal Research, v. 13, p. 209-215.

Hwang, D.J., 2005. Hawaii Coastal Hazard Mitigation Guidebook, University of Hawaii Sea Grant College Program (UNIHI-SEAGRANT-BA-03-01), 216p.

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