Effect of artificial structures on shoreline profile of Selingan Island, Sandakan, Sabah, Malaysia

Abstract

Selingan Island off Sandakan, Sabah is a famous turtle nesting ground and gazette as Turtle Island Park (TIP) within Malaysian Coral Triangle areas. However, beach erosion contribute to loss of turtle nesting area on the island. To counter this, Sabah Parks had deployed stone revetments in 2005, followed by the reef balls deployment at the southern part of the Selingan Island in 2007. Therefore, objectives of this study are to determine the shoreline changes and reef balls’ effectiveness as shoreline protection. Shoreline changes were determined from satellite images, beach profiling and field observation. Two years interval of satellite images from 2010 to 2016 were obtained from Google Earth Pro, analyzed and overlaid to determine changes of shape and size of the island with QGIS software. Beach profiling was performed on 29th December 2017 at three sites and compared with 2011. The findings indicated that the shape of the island was squeezed towards the east where the reef balls were located. The size of the island does not change much within 9 years after the deployment of the reef balls, but a high volume of sediments accumulated at the south due to the presence of shoreline protection. Generally, the man-made structures in Selingan Island are effective trapping sediment and provide more nesting area for turtles. It is recommended that the dynamic of the island should be monitored by analyzing more satellite images or photos to reflect the changes of the island for better understanding on the changes of the island.