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Near-Shore Bathymetric Survey for Coastal Erosion Monitoring in Chalkidiki, Greece

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Integrated Systems

Near-Shore Bathymetric Survey for Coastal Erosion Monitoring in Chalkidiki, Greece

June 12, 2026

Geosense, a provider of unmanned solutions in Greece, carried out a UAV-based bathymetric survey near Kallikrateia, Chalkidiki, to support an environmental impact study focused on coastal erosion and seabed changes. Using SPH Engineering’s drone-based bathymetry kit with a DJI Matrice 300 RTK (real-time kinematic) and Echologger ECT D24S echo sounder, the team collected detailed depth data across approximately 1.5 km² of near-shore waters.

Quick Facts

Partner: Geosense
Location: Kallikrateia, Chalkidiki, Greece
Application: Coastal erosion monitoring
Survey area and flight time: approximately 1.5 km² and 14 hours over 3 days
Challenge: Collecting high-density bathymetric data in shallow coastal waters
Solution: SPH Engineering drone-based bathymetry kit with Echologger ECT D24S dual-frequency single-beam echo sounder, SkyHub onboard computer, and UgCS flight planning software.

Background

Coastal erosion is an active concern along the Chalkidiki coastline, where shifting seabed sediment changes the underwater profile from season to season. In Kallikrateia, Chalkidiki, Geosense was tasked with collecting accurate bathymetric information to help assess shoreline deformation and underwater topography changes.

The project area covered approximately 1.5 km². For a site of this size, manual measurements would not be practical. Traditional boat-based echo sounding is slow and difficult to run in shallow water as well. A UAV-based approach allowed the team to work closer to the shoreline and collect dense measurements with greater operational flexibility.

Challenge

The survey required accurate depth measurements across a dynamic coastal environment. Several field conditions had to be managed during planning and data collection:

Shallow near-shore waters where boat access can be limited
Shoreline proximity and changing underwater topography
Potential obstacles, including rocks, buoys, pipes, and other structures
Wind gusts reaching up to 8 m/s
Sailing vessels occasionally crossing the survey area

These conditions required careful mission planning, stable equipment, pre-survey obstacle mapping, and constant visual line-of-sight control throughout the operation.

Drone-Based Bathymetry Setup

To complete the project, Geosense deployed SPH Engineering’s drone-based bathymetry kit on a DJI Matrice 300 RTK. The setup included an Echologger ECT D24S dual-frequency single-beam echo sounder for depth measurements, SkyHub onboard computer, and UgCS flight planning software.

DJI Matrice 300 RTK with a drone-based bathymetry kit prepared on the beach before a coastal survey in Greece. — DJI Matrice 300 RTK equipped with SPH Engineering’s drone-based bathymetry kit before the coastal survey in Chalkidiki.

This configuration allowed Geosense to maintain low-altitude, steady-speed data collection in shallow near-shore waters, where boat-based surveys are slower or harder to carry out safely.

UgCS mission planning interface showing UAV bathymetry survey routes along the coastline in Chalkidiki. — UgCS flight planning software was used to plan bathymetric survey routes along the near-shore area.

Two-Stage Survey Workflow

The work was carried out in two main stages: coastal mapping and bathymetric data collection. Before the bathymetric flights, Geosense created an orthomosaic of the coastline. This preparatory step helped the team:

Define the shoreline at 0 m elevation
Identify rocks, floating obstacles, pipes, buoys, and other potential equipment risks
Plan the bathymetric mission more safely before flying over water

The bathymetric survey was conducted in November, outside the peak tourist season, to reduce interference from marine traffic and beach activity. During data collection, the drone flew at approximately 1.9 m above the water surface with a ground speed of 0.8 m/s. The full field operation took 3 days and totaled about 14 hours of flight time.

DJI Matrice 300 RTK carrying an echo sounder over coastal waters during a UAV-based bathymetric survey. — The UAV bathymetry kit collected depth measurements while flying at low altitude above the near-shore survey area.

Bathymetric Survey Results

The collected data was processed into a detailed bathymetric model of the survey area. Vertical accuracy and point density were aligned to IHO (International Hydrographic Organization) Order 1 expectations for near-shore work, the standard reference framework for hydrographic survey quality. The final deliverable was a .dwg CAD file containing:

High-density bathymetric points
Accurate shoreline delineation
Bathymetric contours at 50 cm intervals across the survey area

Bathymetric survey deliverable showing coastal orthomap, shoreline delineation, depth points, and contour lines. — Processed bathymetric survey output showing shoreline delineation, dense measurement points, and depth contours.

Colored bathymetric model of the near-shore coastal area with contour lines showing seabed depth changes. — Colored bathymetric model visualizing depth variations across the near-shore survey area.

These outputs provide a baseline for local authorities and project stakeholders to monitor erosion, and plan coastal protection measures based on reliable near-shore depth information.

Conclusion

Drone-based bathymetry complements traditional boat-based hydrographic surveys in the shallow near-shore zone where vessels can't safely operate. The Kallikrateia dataset gives local authorities a baseline against which to compare future surveys, turning a one-off measurement into a repeatable coastal erosion monitoring workflow.

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