Historical shoreline change and cultural sites, Kawela-Kahuku, O‘ahu

Abstract

Hawaii’s beaches are a focus of modern lifestyle as well as cultural tradition. Coastal erosion threatens areas that have served as burial grounds, home sites, and hold other forms of cultural significance. To improve understanding of the convergence of erosion patterns and historic uses, we mapped shoreline changes from Kawela Bay to Kahuku Point. Shoreline change rates are calculated from historical photographs using the single-transect (ST) and eigenbeaches (EX, EXT) methods to define the 50 and 100- year erosion hazard zones. To ensure that shoreline change rates reflect long-term trends, we include uncertainties due to short term shoreline position and other mapping errors. A hazard zone overlay was compared to cultural data provided by the State Historic Preservation Division and the Office of Hawaiian Affairs to identify threats to cultural features. Cultural features identified in the study include burials, artifacts, Pohaku Puo`o, and Punalua pond. A number of sites known to contain burials and cultural artifacts were found within the erosion hazard zones.