Wednesday, October 15, 2025

Lidar + Sonar = a revolution in seafloor mapping

Seamless topobathymetric Lidar digital elevation model (DEM) of an area of the Dry Tortugas National Park, Florida.
 
Visualization with NOAA raster chart in the GeoGarage platform
 
From Hydro by Ryan Cross, Dave Neff, Karen Hart 

How the ambitious Florida Seafloor Mapping Initiative is setting the standard for our understanding of coastal environments

Beneath the sunlit waves of Florida lies an intricate underwater world that few have seen but many depend on.
Through the Florida Seafloor Mapping Initiative, Woolpert and partners are capturing this hidden landscape in unprecedented detail.
Using aircraft, ships and uncrewed vessels equipped with Lidar and sonar, they have mapped tens of thousands of square kilometres despite hurricanes and rough seas.
The resulting seafloor model will enhance navigation, habitat protection and coastal resilience while deepening understanding of Florida’s marine environment.

There are few regions of the United States as defined by or as dependent upon their coastal waters as the state of Florida.
Florida’s annual maritime economy is valued at US$402 billion, incorporating tourism, commerce and trade.
Cruise and cargo operations alone contribute to at least US$117 billion and over 900,000 direct and indirect jobs across the state, according to the Florida Ports Council.

Florida Seafloor Mapping Initiative

At a time when shifting climate patterns are affecting coastal regions around the world in myriad, often undetermined ways, and with a need to understand coastal vulnerabilities and other issues, Woolpert and partners embarked on the ambitious Florida Seafloor Mapping Initiative (FSMI), a multifaceted project led by the Florida Department of Environmental Protection (FDEP) to create a high-resolution seafloor surface model of the state’s coastal waters.

Deploying aircraft, ships and uncrewed surface vessels, the team mapped tens of thousands of square kilometres of the Florida coast.
Using Lidar sensors from the air and multibeam sonar technology from the sea – a combination of technologies deployed at a scale not previously attempted – the team has generated highly-detailed imaging of Florida’s underwater environment.

Since October 2023, experts and technicians have faced down hurricanes, freezing winds and weeks spent on ships far offshore.
But with significant and wide-ranging project outcomes expected, the effort is deemed worth the challenges.

Slated for hosting on the website of the National Centers for Environmental Informationand the Florida Geographic Information Office, this sophisticated mapping database will help with habitat and ecological management, promote methods for safer navigation and assist with fishery and other resource management efforts.
It is also expected to aid with coastal resilience efforts, the identification of precise locations of shipwrecks and other popular underwater tourism sites, and provide a host of yet-to-be-determined returns.

What is more, making the data available to the public allows anyone – from recreational fishers to curious students anywhere in the world – to see and experience exactly what lies underneath Florida’s coastline.

 
RV Thunder is owned and operated by Woolpert.
This purpose-built vessel surveyed in both the Gulf of Mexico and on the Atlantic coast.

Mapping from the air

Woolpert’s topographic-bathymetric (topobathy) Lidar mapping efforts focus on FSMI’s Region 3, covering nearly 27,000 square kilometres off the southern coast of Florida, including the Florida Keys, the remote Dry Tortugas National Park and parts of the south-east Gulf of Mexico.
Since October 2023, four aircraft equipped with Leica Chiroptera-5 and HawkEye-5 sensors have conducted five mapping expeditions, collecting seafloor data to depths of 48 metres.

With priorities centred on shallow-water regions, the Lidar imaging has uncovered submerged channels critical for navigation, blue holes and carbonate banks.
It also generated detailed datasets for habitat systems and environments crucial to the health of manatee populations, coral reefs and mangrove forests in places such as the Big Sable Creek mangrove forest ecosystem in the Everglades National Park.

The ability of topobathy Lidar to collect huge swathes of data using a single flight line makes it a key tool for completing projects quickly and accurately.

Bathymetric data acquired in 85 metre depths off Florida’s Atlantic coast.
The dunes are about 15 metres tall and continue for hundreds of kilometres.

And from the sea

Deploying up to eight boats ranging from 50 to 130 feet in size, the sonar surveying operations have covered nearly 18,000 square kilometres of seafloor in areas within regions 1 (north-east Florida), 5 (the Big Bend region) and 6 (the Florida Panhandle).
To improve the efficiency of the sonar operation, sections of the mapping process saw a dual-head setup on ships that supported a wide swathe of surveying, boosting coverage areas to five times the water depth in shallow water.

Woolpert exclusively uses R2Sonic (2022, 2024 and 2026) multibeam sonar surveying technology systems that can scan more than 200 metres beneath the surface of the sea.
While some of these coastal areas have been mapped in the past, this project stands out in its ability to deliver higher resolution and image quality than achieved before to establish a new level of clarity.
And while past projects have relied on autonomous vessel mapping, this FSMI project is the first of its scale to deploy over-the-horizon autonomous systems, meaning these vessels are operating uncrewed and alone in open water.
Satellite technologies such as Starlink enable surveyors and technicians to be on the vessels, virtually.

Project technicians remotely operated the autonomous, uncrewed vessel MC29, which can work for weeks at a time using Starlink communications.
Woolpert installed its equipment on the 29-foot-long vessel, which was operated by Chance Maritime pilots, to map around 2,150 square kilometres of seafloor.
This remote MC29 operation made the project far more efficient than when requiring a traditional crewed vessel.

Woolpert deployed a ‘follow the sun’ system, whereby data collectors based in South Carolina, Alaska, Australia and Ireland maintained a 24-hour system to collect data remotely and in real time.

More than a dozen wrecks were mapped in the bathymetric data including this 170 by 70-metre floating drydock that was sunk in 40 metres of water to create an artificial reef.

Far-reaching goals

The scale and ambition of the FSMI project served up challenges and opportunities to propel new advancements in equal measure.
In similar projects, mapping is conducted typically only during the summer months, when surface water conditions are relatively calm.
This short mapping season could have turned the FSMI project into a three- to five-year endeavour, but the Woolpert team kept working throughout the year, often in challenging sea conditions.

Florida’s coastal waters routinely face weather not seen in most other parts of the world.
For five months of the year, hurricanes can be a major concern for residents, businesses and tourists.
Allocating vessels while attempting to anticipate storm tracks as they rolled through western Florida during the second half of 2024 proved to be a challenge for project managers working to keep the FSMI project on track.
In October 2024, Hurricane Milton, the strongest tropical cyclone to have occurred anywhere in the world that year, wreaked havoc across Florida’s peninsular coast in the form of widespread damage and fatalities.

Another daunting challenge was managing and processing petabytes of data.
Data collection from multiple sensors on up to four different aircraft could have resulted in significant variances in datasets.
To remedy this potential obstacle, the Woolpert team automated much of the offshore processing, including such processes as noise removal, to save significant time and align with the project budget.
Occasionally, environmental challenges such as water turbidity resulted in the need for reflown flight lines.

MC29 uncrewed surface vehicle that acquired over 2,500 square kilometres of bathymetric data in the Panhandle Region of Florida.

Opportunities to innovate

The FSMI project presented the team with more than just challenges; it also offered opportunities for learning and adaptation, opening the door for more innovation going forward.
After Hurricane Milton hit the Tampa Bay region, a nearby Woolpert research vessel quickly mobilized to map the artificially dredged shipping channel leading into Tampa Bay to identify any debris blockages.
This effort enabled large tanker traffic to quickly enter the bay in the crucial hours and days following the devastating hurricane.

Moreover, in past projects, vessels typically went offshore for days or weeks at a time, returning with massive banks of data.
To support a more continuous project schedule, the Woolpert team developed a data workflow plan leveraging automation, autonomy and innovative new technology.

Now, thanks in part to satellite systems such as Starlink, that data can be received and processed in a continuous, steady feed in real time, cutting out potential data transfer bottlenecks and uneven demands for computing power – two issues that can significantly disrupt the flow of a project of this scale.

In addition to the technical learnings the project has presented, the team uncovered a host of critical environmental data points.
For example, when coastlines require repair in the aftermath of storms – an issue that many scientists expect to become more prominent in the years ahead – repair crews will know exactly where to look for the large underwater sand deposits essential to completing the projects, thanks to the mapping efforts.
What is more, we know that reefs can act as a buffer to protect metropolitan areas from storms and sea surges.
Finding and mapping those reefs now means that communities may be better prepared to deal with the adverse effects of severe weather events.

By bringing together a host of contractors and interests to map its state waters, FDEP has displayed remarkable ambition and teamwork.
And with an estimated US$28 million annual return on investment, Florida seafloor mapping is an asset that is set to pay off for Floridians today, tomorrow and well into the future.

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