Expanding a harbor to accommodate larger ships sounds straightforward until the dredging equipment encounters solid granite beneath the seafloor. While loose sediments like sand, silt, and clay can be excavated relatively easily, unexpectedly striking hard bedrock can quickly slow a project, increase equipment wear, and drive up costs. Before any dredging begins, engineers must know not only how deep the harbor is but also what lies beneath it.

Those were the two questions facing a Norwegian city that wanted to deepen an aging harbor so larger vessels could safely dock. To answer them, Alexey Shulgin, Chief Geophysicist at Norway’s Submara Survey, combined drone photogrammetry, high-resolution bathymetry, and sub-bottom seismic profiling to build a comprehensive look of the harbor from the shoreline all the way down to the underlying bedrock.

But how did he transform several independent datasets into cohesive visualizations that engineers could confidently use to guide a major dredging project? Let’s walk through Alexey’s workflow from data collection to final deliverable.

First, it’s worth taking a step back to understand why this project required more than a single survey method. The main reason is that no single dataset could answer the client’s central question: where can they safely and efficiently deepen the harbor?

For example, high-resolution bathymetry could provide a detailed picture of the seafloor, making it invaluable for understanding harbor depths and underwater topography. But it couldn’t reveal what lies beneath the seabed. On the other hand, boreholes could provide highly accurate information about subsurface conditions, but only at the exact locations where they’re drilled. Conditions between boreholes would largely remain an educated guess.

That’s why Alexey combined multiple datasets rather than relying on a single source of information. By integrating a drone-derived surface model, high-resolution bathymetry, and sub-bottom seismic data, he could create a complete picture of the site so engineers could calculate excavation volumes with greater confidence, select equipment better suited to the site’s conditions, and reduce the risk of unexpected bedrock slowing or complicating dredging operations.

With the value of an integrated site investigation understood, Alexey’s first step was collecting the data needed to build a complete picture of the harbor. He gathered information above the water, across the seafloor, and beneath it to ensure engineers understood not only the harbor’s current shape but also what lay below the surface. Here’s a deeper look at his data collection method.

After collecting the necessary data, the real value came from bringing those datasets together into visualizations that engineers could quickly interpret and use for decision-making. To complete this step, Alexey processed the drone imagery, bathymetry, and seismic data in their respective software. From there, he imported the outputs into Surfer, where he combined them through visualization and spatial grid calculations. Here’s how those individual datasets came together to tell the complete geological story of the harbor.