Beach Changes on Coral Cay Associated with Artificial Alteration of Inlets—Example of Meedhoo Island in Maldives

Beach erosion that occurred as a result of anthropogenic interventions on a coral cay, Meedhoo Island, in Addu Atoll in the Maldives, was investigated. The field observation and analysis of shoreline changes using aerial photographs and satellite images were carried out. With the beach erosion, the beach rock beneath the sandy beach was exposed to waves and destroyed. Moreover, the closure of a natural inlet affected the shore of a coral cay, causing a decrease in sand supply to the shore. In another case, in which a new inlet was excavated to form a deep channel near the shoreline, the sand carried by longshore transport was trapped in the excavated hole, resulting in the erosion on nearby beaches. It was concluded that the closure of the natural inlet blocked the supply of sand from the ocean to the lagoon side, and the removal of sand caused the loss of sand on beaches. Note that the development of coral cays must be carefully carried out so as not to cause these adverse effects, and the natural mechanism of forming coral cays must be maintained.