A Guide to Bathymetric Surveys

It is not just land above sea level that has to be mapped and measured – but underwater land as well. One of the key methods for mapping the surface below water is using a bathymetric survey. <–more!–>

What is it?

The expression “bathymetry” identifies the analysis of this terrain and shapes of land underwater, like lakes, rivers, or oceans.

Bathymetric surveys are a sort of hydrographic survey that measures the depth of water and also maps out the form of the seabed. They could help draw a comprehensive map of the different shapes and characteristics of the submerged terrain.

What are they used for?

Bathymetric surveys serve many different uses and therefore are helpful on both small and massive scales. Knowing the bathymetry of underwater terrain can tell us a lot about what happens over the surface.

By way of example, the shape of a riverbed can help determine the speed, temperature, and other features of their water flowing above it. Water reacts in various ways depending on the shape of the land beneath it.

One of the most common applications for this kind of survey is to ensure safe surface or sub-surface navigation along waterways. Captains of both little river ships and big commercial boats use bathymetric surveys to determine the route they will take to reach their destination safely, as the bathymetric survey demonstrates where both deep and shallow waters are.

It is important to note that these surveys differ from hydrographic studies in that they aren’t as accurate for use in safe navigation. Bathymetric surveys are way more detailed than hydrographic details at outlining the terrain whereas hydrographic surveys especially make the charts much easier to comprehend for navigators.

How are they drawn?

Through the years, the methods used for generating bathymetric surveys have shifted appreciably. In the very early phases of bathymetry, easy techniques like falling long chains or ropes into the water from a boat were utilized to assess the depth of the water and create fairly inaccurate bathymetric surveys.

This method later progressed to echo sounders which were placed under or on the side of boats. The echosounder would ping a beam of noise towards the ocean floor and the amount of time it took for the sound to travel through the water, hit the seafloor, and return indicates how deep the water is (in a similar way to how pregnancy ultrasounds are created).

These days, echo sounders are still one of the most usual types of creating bathymetric surveys – however, they have progressed from single-beam sounders into multi-beam echo sounders (MBES). These have tens of thousands of very narrow beams that stretch around 170 degrees across allowing fast, accurate coverage of this terrain.

Echosounders work alongside GPS systems. The GPS notes the current location through a time tag simultaneously with the reading from the echosounder. These two readings could be placed together to produce both a bathymetric map and a 3D view.

Who makes them?

In the USA, surveys of the Vast Majority of navigatable inland waterways are conducted from the United States Army Corps of Engineers. Ocean bathymetric surveys are generally commissioned by the National Oceanic and Atmospheric Administration.

Bathymetric surveys may also be conducted using your sonar equipment (which could be very costly ) or by hiring a professional that can conduct a more particular questionnaire for you.

Where to Locate

Many surveys are available for the public to access absolutely free of charge – particularly of major waterways.

R2Sonic mining technology is designed to collect bathymetric, backscatter, and water column data to serve the whole spectrum of possible end-users, from dredgers, ports and harbor surveyors, miners, scientists, and the spectrum of further offshore professionals.