Deltares: What is the impact of sea level rise on atoll islands?

A team of international researchers is investigating the potential for the world’s low-lying coral atoll islands to withstand predicted sea level rises through natural flooding processes.

Recently, Deltares experts Robert McCall and Floortje Roelvink joined the international research team for fieldwork in the Maldives. They collected data to support predictions of how these islands might respond to future sea level changes.

The research is done within the larger project ARISE. 

ARISE is led by the University of Plymouth and is a project of £2.8 million, lasting five years and funded by UK Research and Innovation’s Horizon Europe Guarantee programme.

Atoll islands are wave-built accumulations of gravel or sand that sit on top of coral reef platforms.

The island sediments are derived from the breakdown of calcium-carbonate secreting organisms, such as corals, bivalves, gastropods and foraminifera, that dwell on the adjacent reef systems.

“The existence of these islands is intrinsically linked to the reef ecology, as they rely on the reef’s production of sediments; however, the formation, maintenance and dynamics of atoll islands are primarily governed by physical processes involving water level, waves and currents,” said Deltares.

In the following period, the ARISE project will continue with over two months of testing in the Deltares Delta Flume. 

“In these tests, we will explore how islands morphologically respond under different hydrodynamic forcings. The concrete reef platform has already been constructed and over the next weeks, a wide range of instruments will be installed and the sandy island placed,” said Deltares.