LiDAR Imagery Data in Tuvalu a crucial tool to understand climate change impacts and plan adaptation

LIDAR (Light Detection and Ranging) is a form of aircraft-mounted survey that captures very accurate ground height and seafloor information. This data when combined with on-site sea level measurements and ground control surveys is a game-changer. For the first time ever the relationship between sea level and ground height across all of Tuvalu’s islands is accurately understood. Such data can inform safe development, infrastructure planning, and adaption. It also provides the best possible baseline to understand climate change impacts such as wave and sea-level rise flooding and shoreline change.

In May 2019, the United Nations Development Programme implemented Tuvalu Coastal Adaptation Project (TCAP) funded by the Green Climate Fund (GCF) engaged a leading hydrographic survey and geophysical services company (Fugro). Fugro have significant experience in small island airborne topographic (land surface) and bathymetric (seafloor) surveying. It is a state-of-the art airplane-mounted technology which can rapidly collect precise information on land surface height and sea level floor depth

“The LiDAR data acquired by UNDP through the Tuvalu Coastal Adaptation Project in 2019 (carried out by the Fugro company) has greatly reduced the workload usually carried out by Officers of the Department,” said the Director of the Department Lands and Survey Faatasi Malologa.

He added that not only did the Department of Lands and Survey benefit from the LiDAR data, but all Departments of other Ministries benefited from it as well. This was evident as they frequently visited the office to collect the LiDAR imagery and data for other projects and work being being carried out in Tuvalu.

Tekita Tuinanumea at the Public Works Department (PWD) says he uses the LiDAR data to develop road construction plans for small access roads in the village on Funafuti. The PWD Engineer emphasized that the data is very useful, as it provides precise contour lines and assists in the planning for better road design and construction. He added that the data shows the extent of high tide flooding in Fogafale and his Lidar informed plans can now accommodate this flooding by raising the surface levels.

Mr Tuinanumea said that the LiDAR data was also used during the Public Works Department’s GIS (Geographical Information System) training and he explained the improved data gave more understanding and that the data were very good quality and the imagery were clear allowing the user to zoom into a target any area and get a clear view of features on the ground.

The same sentiment was shared by the Department of Environment who conduct scoping for Environment Impact Assessments. According to Faoliu Teakau an Officer in the Department, “the Lidar provides better information for assessments and development applications and helps address environmental impacts”. Mr Teakau also mentioned the importance of the Lidar data for future planning, “for future development planning, the LiDAR data can provide a better idea of safe sites for a proposed development”.  

The data are also being used by the department to understand shoreline change. This national baseline has saved time and budget for the Department, as collecting this data across the whole country manually would take many months of travel and field work.

 Feagaiga Penivaoo, of the Ridge to Reef Project said the LiDAR imagery data have benefited the Tuvalu Ridge to Reef project to update their biodiversity land survey and marine survey. “With land conservation on coastal protection, the imagery data enabled the project to identify sites which need to be protected and to identify sites where vegetation can be re-planted. Mapping out conservation areas and assessing coastal change has also been possible using the new data.”

Mr Penivaoo is also an EIA Consultant for the outer islands airfield project, “the availability of the imagery data made far easier to carry out surveys for social and environmental impact on the land and sea”.

GIS Training facilitator by Lamese Saamu said, “the data provided by TCAP is called a Digital Elevation Model, and noted that  data are so clear, detailed and very useful.” Mr Saamu facilitated a Training of the Trainers to use the data with the Department of Environment and other stakeholders. He said that the training was very productive as the participants were all excited to understand and to read the data using the freely available QGIS program.

“The QGIS program is excellent for viewing this type of information and at the end of the training the participants were able to use the QGIS program to extract information from the Lidar data.”

Mr Faatasi Malologa, the Director of Department of Lands and Survey who was a crucial partner in the successful collection of the 2019 Lidar data said, “It is crucial to update LiDAR imagery data routinely. Every decision for future development requires this type of data and on atolls, it is very important that we have an accurate understand of changing shorelines and any changes to our reefs and land. LiDAR is the best way of collecting this data, quickly and accurately and is extremely useful to the department.

He said there have been changes in the islands due to strong storms that hit between 2019 to 2021 and the best way to analyze this change would be to collect Lidar again and compare the data sets. Mr. Malologa said, “the Department of Lands would like to acquire its own Lidar equipment to collect data more regularly for the whole country, but such equipment is very expensive and the Department does not have the budget to purchase such equipment,” said Faatasi.

In 2020, TCAP and the Department of Lands in Tuvalu raised awareness on the LiDAR data in the Capital Fogafale and since then, other government ministries have found it beneficial, and the Department of Lands has received many requests for the data.

The new data shows clearly the challenges of climate change and sea level rise in one of the world’s most threaten nation. The national coverage in Tuvalu and the accuracy of the data is a first in any atoll country in the Pacific and given the huge success in Tuvalu it seems many other countries will request similar surveys.

It is often not understood that such data is absent in most of the Pacific Island Countries and that survey of this type are cost effective and extremely fast. In only two weeks the survey aircraft covered all of the land, reefs and lagoons across all nine atolls of Tuvalu. The survey also captured aerial photographs of unprecendented accuracy and clarity, and when combined with the LIDAR topographic data provides a very powerful 3-dimensional tool for use in hazards management, adaptation and many many other uses.

For a small island nation battling the impacts of climate change and sea level rise such data is crucial. In atolls centimeters matters and this is the only way to get the type of quality baselines required for impacts management and adaptation. It is astonishing to understand that 2019 was the first time ever that the relationship between sea level and land height across Tuvalu was clearly defined, what could be more important in an atoll country!

The UNDP Pacific sees the project has benefited the nation enormously said Alan Resture the National Project Manager of the TCAP – UNDP,  he added that “people do not see this benefit coming from LiDAR. Once it is explained to them, then they realise how powerful the data is. One of the main benefits that is yet to be acknowledged is the Prime Minister’s speech at COP26, that 40% of Fogafale’s land area is inundated during King tides. That figure is a direct result extracted from LiDAR data”. In essence, UNDP through TCAP is not only focused on the 3 island communities in terms of adaptation measures, but for the whole country. Data from LiDAR survey is now widely used by Government Ministries for their own purposes.

About TCAP:

The Tuvalu Coastal Adaptation Project (TCAP) is a seven-year Green Climate Fund (GCF) funded program implemented by the United Nations Development Program (UNDP) in partnership with the Government of Tuvalu. It has the overarching objective of reducing marine hazard exposure in Tuvalu through both national components and targeted physical works on two outer islands and on the national capital Funafuti. Tuvalu’s small remote low-lying islands are understood to be among the most exposed to sea level rise and climate change threats on earth and improve understanding of these unique environments is crucial to managing threats from marine hazards.