TOPOGRAPHIC CHANGES ON CORAL CAY CAUSED BY CLOSURE OF INLET

Abstract

 On tropical island countries, coral reefs well develop, and coral sand is transported shoreward due to waves for a coral cay to be formed. On these coral cays, the ground elevation is so low that strong impact by sea level rise may occur. On the other hand, the significant impact to the coral cay may be also caused by artificial modification related to the rapid economic growth, resulting in beach erosion of the island. In this study, beach changes triggered by the closure of an inlet located between Kaddhoo and Maandhoo Islands in south Laame Atoll in the Maldives were investigated. After the closure of the inlet, a foreshore was formed by the shoreward sand transport originated from sand deposited on the lagoon side. The rate in the volume of the foreshore on the lagoon side was measured to be 1.8×10⁴ m³/yr between 2018 and 2021. Moreover, it was found that to maintain the sand supply from the ocean to the lagoon side, the inlet of funnel type is needed.