Our Hydrographic Surveying Capabilities
Our in-house survey crews use the latest equipment and technology to perform high resolution hydrographic surveys. We utilize a variety of tools and skills to produce the detailed data you need to make informed decisions.
Our ability to verify data from scanning sonar or multibeam surveys with diver verification is a key tool in the in-house capabilities of S. T. Hudson. In addition, our hydrographic surveyors use real-time kinematic (RTK) positioning to broadcast to survey vessels, achieving centimeter-level vertical and horizontal accuracies. When remote geographic locations make this impossible, we use software to post-process the data to the same tolerances as RTK.
Our certified hydrographers and engineers consult on a variety of dredging related issues, including preparation of specifications, pre- and post-dredging surveys, monitoring of siltation rates, volume calculations for payment quantities, and assistance in obtaining required local, state and federal permits.
Our solid background in underwater construction allows us to deliver cost-effective repairs, prioritize construction, and make reliable estimates so our clients can appropriately allocate and schedule maintenance funding. Our services include:
- Multibeam Hydrographic Surveys - Good for collecting depths in mid- to deep-water columns, multibeam hydrographic surveys can serve two purposes: berth clearance and condition surveys.
- Dual-Frequency Single Beam Surveys - We use dual-frequency single beam surveys to determine water depth by measuring the travel time of a short sonar pulse, or “ping”. Hydrographic survey-grade single beam echo sounders are able to provide accurate bottom depths by distinguishing the real bottom from false readings caused by fish, debris, aquatic vegetation and suspended sediment.
- Scanning Sonars - This tool is used for object detection, sending out a sound wave that reflects off objects and can be used regardless of water visibility.
- Side Scan Sonars - Used for object detection, side scan sonar measures the strength of returning echoes to create an image of the sea floor.
- Sub-Bottom Profiling - Using principles of seismic reflection, sub-bottom profiling can identify and characterize layers of sediment or rock under the sea floor.
- ROV Operations - We utilize remotely operated vehicles (ROVs) to investigate areas where divers cannot operate safely.
- Magnetometer - This instrument, used for measuring the magnitude and direction of a magnetic field, can detect magnetic anomalies beneath the surface.