Advanced Topographic and Bathymetric Survey to Support Tuvalu’s Adaptation Efforts

April 24, 2019

The aircraft that will carry out the LiDAR survey for the nine atoll islands of Tuvalu. (Photo: Fugro)

Funafuti, Tuvalu
- Detailed and accurate information on the relationship between land height and sea level will be made available for the first time since sea level rise became an issue of concern to Tuvalu.

The Tuvalu Coastal Adaptation Project (TCAP) funded by the Green Climate Fund (GCF) and implemented by the United Nations Development Programme (UNDP) has signed a contract with Fugro to undertake an airborne LIDAR survey across Tuvalu’s nine atoll islands in the coming month. LIDAR (Light Detection and Ranging) is a remote sensing method that uses light in the form of a pulsed laser to measure ranges to the earth.

“Government will see the provision of this data as an extraordinary step forward to improve plans and understand the country’s resources and vulnerability,” said UNDP Pacific Office in Fiji Resident Representative a.i., Vineet Bhatia.

“Important services such as navigation in shallow waters will be enhanced and the baseline will be of key interest to development partners and local authorities interested in adaptation, infrastructure development, natural resource management and environmental monitoring,” said Bhatia.

The threat of ongoing sea level rise and changing occurrence of severe tropical storms means that Tuvalu’s small low-lying islands are being subjected to increased exposure to wave overtopping events, marine flooding and inundation.

In March 2015, Cyclone Pam caused widespread damage through wave overtopping and marine flooding of low-lying areas affecting some 30% of households nationally. Additionally, the occurrence of clear weather flooding has increased in the capital, Funafuti, because of its extremely low-lying nature. A combination of seasonal and predicted high spring tide causes marine waters to infiltrate through the island causing pooling of marine water over large areas of the island.

Between 1994 and 2012, 28 events have been documented, five of which have occurred since 2010. This phenomenon occurs across many islands in the group and only increases in frequency, extent and severity due to ongoing sea level rise.

TCAP Project Manager, Alan Resture said “To successfully model and thus assess the risks of either wave overtopping impacts or the gradually increasing inundation events in low lying areas of Tuvalu, high quality baseline data is required. Detailed reef edge bathymetry (sea floor mapping to 50-meter depths) and accurate topography (land elevation data) is absent in Tuvalu except for limited coverage in Funafuti.” 

He added, “Without these fundamental baselines, the relationship between water levels or wave dynamics and land cannot be accurately assessed. At one end of the spectrum, the international community has hugely increased its ability to measure sea level in recent years and trends are reported with sub-millimeter accuracy. Yet the crucial relationship between land height in Tuvalu and sea level rise remains undefined and we rely on hazy anecdotes such as low-lying islands to report average land elevation above average sea level.”

The LiDAR survey will provide accurate national coverage of shallow (0-50m) near shore and lagoon seafloor bathymetry and island topography across all nine islands, to primarily support TCAP’s island vulnerability assessment work and feed into a very broad spectrum of vulnerability, adaptation, development, resources management and environmental monitoring needs in Tuvalu.

The survey data, which will show more accurately than ever before, the precise relationship between land height and sea level. It will provide not only a fundamental baseline for national vulnerability assessment and planning but will also serve as an integral baseline for shoreline monitoring. Similarly, the seafloor data could be used for a large range of uses from navigation to fisheries management to pollution studies and many others.

“In the case of TCAP, data from the land and sea floor surveys will be used to model wave impacts from cyclones and actively inform engineering designs on mitigation of these impacts,” said Resture.

Fugro is expected to commence the airborne LiDAR survey towards the end of May 2019.

TCAP is working in close consultation with the Tuvalu Aviation Department as well as the Police Department to raise awareness with all island communities on the operational and safety features of this airborne LIDAR survey works.

Contact information:

Alan Resture, TCAP Project Manager, Partnership House, Funafuti, Tuvalu; tel: (688) 20258; email:;

Puanita Ewekia, TCAP Communications Officer, Partnership House, Funafuti, Tuvalu; email:;

About TCAP:
Website:; Twitter: @TCAPforTu8; Facebook: Tuvalu Coastal Adaptation Project