Awāwāmalu, also known as Sandy Beach, is located on the south coast of Oʻahu in a small embayment at the base of Kohelepelepe (Koko Crater), bounded to the west by high cliffs eroded into the Koko tuff and to the east by a low basalt point. The beach is partially divided by an outcrop of basalt boulders near the water line (“Half Point”). The shoreline is exposed to easterly tradewind waves year-round, southerly swells in summer months, and refracted northerly swells in winter. The eastern portion of the beach is fronted by a shallow reef (“Full Point”) with waves breaking offshore. The western portion is less protected by the nearshore reef and is well known for its powerful shore-breaking waves.
Awāwāmalu is experiencing low to moderate erosion with an average rate of all transects of -0.3 ft/yr. The highest rates (up to -0.6 ft/yr) are found at the west end of the beach. Our results are similar to those of a previous study, which finds net landward movement (erosion) of the vegetation line (Hwang, 1981)*.
* Hwang, D. (1981) “Beach changes on Oʻahu as revealed by aerial photographs”, State of Hawaii, Department of Planning and Economic Development.
Last updated: July 2021
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