Application of Bathymetry and Hydroacoustic Technology
Bathym… what?! You read correctly. Bathymetry, a form of hydroacoustics, may seem like a strange word but it represents a common field study measurement of water depth, typically in oceans, seas or lakes. Using echolocation, where sound waves are sent out and returned, bathymetry surveys are used to map out beds of bodies of water to establish depth and any underwater features (i.e., underwater canyons, the mid-Atlantic Ridge, underwater volcanoes).
Typically with bathymetry, equipment is attached to a survey boat and the boat drives across the area to be surveyed. That equipment uses echolocation to measure the time it takes the sound waves to travel first from, then back to the boat. From that measurement the depth can be determined.
Waterborne first acquired Bathymetry technology in 2014 with the primary intention of using it for conducting flow measurements on our stream and large river monitoring stations. Since then, we have used it to conduct bathymetric surveys in ponds, perform velocity profiling in streams, and conduct cross-sectional surveys. Recently, Waterborne conducted a study where an Acoustic Doppler Current Profiler (ADCP) was used for a bathymetric survey in a pond.
In our pond study, ADCP was used in conjunction with a GPS receiver mounted in a tethered boat. The ADCP collected depth data with three separate acoustic beams that were averaged to resolve a single depth point via software at a rate of several times a second. A separate software suite was then used to connect the depth data back to its associated GPS location. Repeated surveys were then referenced to a common elevation datum, which helped us determine sedimentation and erosion patterns.
We’ve found that the hydroacoustic science technology, including bathymetry has enormous potential. For example, we’ve deployed it to collect surrogate datasets for constituents such as suspended sediment and/or other constituents that attach themselves to sediment (i.e. certain pesticides and nutrients). With this technology at our disposal, our team has the ability to investigate characteristics of waterbodies in many different ways. The future is looking bright for this science with a funny name!