Why Modern Projects Combine Land and Underwater Surveys into a Single Dataset

Whether designing a bridge, expanding a port, rehabilitating a river, or developing coastal infrastructure, engineers rarely make decisions based solely on what lies above or below the water.

The reality is that land and water are interconnected. Changes in one environment often influence the other, which is why modern engineering projects increasingly rely on integrated survey datasets that provide a continuous understanding of the entire project area.

Rather than treating topographic and hydrographic surveys as separate activities, today's projects often combine multiple survey methods to produce a single, seamless dataset. This approach provides engineers, planners, and designers with more complete information while improving project coordination and reducing uncertainty during design and construction.

In this article, we'll explore why integrated surveys have become the preferred approach for many projects and how different surveying technologies can work together.

Why Combine Land and Underwater Surveys?

Imagine designing a bridge across a river.

Understanding the riverbed alone isn't enough. Engineers also need accurate information about the surrounding terrain, riverbanks, approach roads, floodplains, utilities, and existing structures.

Likewise, surveying only the land would leave a critical information gap beneath the water, where bridge foundations, scour conditions, and underwater obstructions must also be considered.

By combining land and underwater surveys, engineers gain a complete understanding of the project environment, allowing them to make more informed decisions throughout planning, design, and construction.

The same principle applies to ports, dams, reservoirs, coastal developments, flood control projects, and renewable energy facilities. The more complete the dataset, the more confident project teams can be in their designs.

The Benefits of an Integrated Dataset

Combining survey datasets offers advantages beyond simply collecting more information.

An integrated survey allows project teams to:

• Visualize the entire project area in one continuous model.

• Reduce data gaps between land and water.

• Improve coordination between engineering disciplines.

• Simplify design workflows by working from a single reference dataset.

• Support more accurate volume calculations, hydraulic modelling, and infrastructure design.

• Reduce the need for multiple site visits and repeat surveys.

Rather than switching between separate topographic drawings and bathymetric maps, engineers can analyze one cohesive representation of the project area.

Which Survey Methods Can Be Combined?

Different survey technologies complement one another, with each contributing unique information depending on the project requirements.

Aircraft LiDAR + Multibeam Echo Sounder (MBES)

One of the most common combinations for large-scale marine and coastal projects pairs Aircraft LiDAR with Multibeam Echo Sounder (MBES).

Aircraft LiDAR captures highly accurate topographic data across large land areas, while MBES maps deeper underwater terrain with dense seabed coverage.

Together, they produce a continuous digital model extending from dry land into deeper water.

Best suited for

• Port developments

• Coastal infrastructure

• Offshore facilities

• Large reclamation projects

• Marine terminals

Aircraft LiDAR + Aerial Bathymetric LiDAR

In shallow, clear-water environments, two airborne technologies can be used together.

Aircraft LiDAR captures detailed topographic information over land, while Aerial Bathymetric LiDAR measures the seabed beneath clear, shallow water.

Because both surveys are conducted from an aircraft, they provide a highly efficient solution for projects requiring seamless mapping across the shoreline.

Best suited for

• Coral reef mapping

• Coastal engineering

• Shoreline monitoring

• Environmental assessments

• Island developments

Aerial Bathymetric LiDAR + Multibeam Echo Sounder (MBES)

Some infrastructure projects require detailed mapping of both shallow coastal waters and deeper seabed areas alongside surrounding land features.

In these cases, Aerial Bathymetric LiDAR can be combined with Multibeam Echo Sounder (MBES) surveys to provide a continuous and highly accurate dataset that captures both nearshore shallow-water environments and deeper underwater conditions.

Best suited for

• Coastal engineering projects

• Port and harbour developments

• Shoreline and seabed mapping

• Marine infrastructure planning

• Environmental and habitat assessments

Aerial Topographic LiDAR + Aerial Bathymetric LiDAR + Multibeam Echo Sounder (MBES)

A fully integrated airborne and marine survey approach combines Aerial Topographic LiDAR, Aerial Bathymetric LiDAR, and Multibeam Echo Sounder (MBES) to deliver continuous coverage from dry land through shallow coastal waters and into deeper marine environments.

Aerial Topographic LiDAR captures highly accurate elevation data across land-based terrain, including infrastructure, riverbanks, and coastal zones above the waterline. Aerial Bathymetric LiDAR extends this dataset into shallow, clear-water areas, mapping nearshore seabed conditions where traditional sonar may be less efficient. For deeper water, MBES provides dense and highly detailed seabed coverage, ensuring complete bathymetric understanding across the full underwater extent.

When combined, these three technologies create a seamless transition from land to sea, removing data gaps between terrestrial and marine environments and producing a unified model suitable for complex engineering and coastal analysis.

Best suited for

• Coastal infrastructure and shoreline development

• Port and harbour expansion projects

• Large-scale reclamation and marine construction

• Integrated river mouth and estuary studies

• Environmental and coastal change monitoring

Choosing the Right Combination

Not every project requires multiple survey methods.

A straightforward river cross-section survey may only require a Single Beam Echo Sounder. Likewise, a land development project may only require topographic LiDAR.

However, projects that span both land and water often benefit from integrating multiple survey technologies into a single coordinated workflow.

The right combination depends on several factors, including:

• Project objectives

• Water depth

• Survey extent

• Required level of detail

• Environmental conditions

• Engineering and design requirements

Selecting the appropriate combination from the outset helps reduce duplication of work, improves data consistency, and provides engineers with the information they need to make informed decisions.

Final Thoughts

As infrastructure projects become more complex, the need for integrated survey data continues to grow.

Rather than viewing land and underwater surveys as separate disciplines, modern engineering increasingly relies on combining multiple survey technologies to create a complete representation of the project environment.

Whether that involves Aircraft LiDAR with Multibeam Echo Sounders, Aircraft LiDAR with Single Beam Echo Sounders, Aerial Bathymetric LiDAR for shallow coastal environments, or Mobile LiDAR alongside hydrographic surveys, the goal remains the same: providing accurate, reliable, and connected data that supports better engineering decisions.

At AB Surveying, we evaluate each project's requirements before recommending the most appropriate combination of survey technologies. By integrating the right methods, we help our clients obtain a seamless dataset that supports planning, design, construction, and long-term asset management with greater confidence.