Brennan has reinvented the concept of inland waterway hydrographic survey. Using the latest technologies and custom-designed vessels, we have become an innovative leader in underwater mapping and modeling. We have been able to take state-of-the-art technology and apply it to shallow water conditions, a feat that has proven difficult for other survey firms. We have performed detailed surveys of areas around dredge projects, dams, and bridges to create 3-dimensional models of subsurface river bottoms.
Brennan’s full-time, dedicated staff of marine surveyors and engineers has experience in collecting, processing, and assembling survey data to create 3-dimensional models of subaqueous bottoms.
Types of Bathymetric Surveys
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Multi-Beam Echo Sounder
- This method of collecting data is the most effective way of creating detailed 3-dimensional models of the river and lake bottoms. It collects several soundings at once and ties them in with RTK-GPS units to create a very accurate depiction of subaqueous surfaces. – Learn More
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Single-Beam Echo Sounder
- This method uses a single sounding device to collect accurate depth measurements and tie them in with RTK-GPS systems. Data points collected with this system use a greater degree of interpolation to create a 3-dimensional model; however, it can be very cost-effective in gathering important sounding information. – Learn More
Our custom-designed survey vessels can work in very shallow conditions, inclement weather, and around obstacles with a heightened maneuverability. They are specifically designed to work on the inland waterways, allowing them to access shallow areas and remain stable while working around debris, dredge pipe, or other obstacles typically found in the riverine environment.


Typical Hydrographic Survey Applications
- Dredge Cuts
- Dam Structures (Scour and Debris)
- Railroad and Highway Bridges (Scour and Debris)
Equipment Used
- Real-Time Kinematic Global Positioning System (RTK-GPS)
- Single-Beam Echo Sounder
- Multi-Beam Echo Sounder
- Light Detection and Ranging (LiDAR)
- Sector Scan