It has nothing to do with taking a bath. Simply put, bathymetry is the measurement of the depth of a body of water. By using an acoustic sounding device linked with global positioning systems (GPS), we can create a bathymetric map that gives the depths of a lake or pond. The sounder and GPS unit are mounted to a boat then transects are made across the pond or lake. Depths are recorded and paired with a GPS location.

Once the data is collected, it is transferred into a mapping program to generate the bathymetric map. Depending on the sophistication of the equipment and mapping program, an extremely accurate depiction of the bottom of the lake or pond can be given. The bottom contour map provides a model of how things look under the water’s surface. You can even see creek channels and ridges.

Another useful application for bathymetric maps relates to dredging. If a map is created in the early stages of a lake’s life, after many years another map can be created to compare the depths and any accumulated sediment. A map could also be used as a quality control check before and after a dredge project has taken place.

Bathymetric maps can also provide the volume of a given water body. This information can prove invaluable when implementing a whole-lake treatment with an aquatic herbicide. Since the volume of a lake is needed to calculate the amount of plant control material needed, a more accurate lake volume will prevent the use of excess or inadequate material.

Having a bathymetric map of a water body is an invaluable piece of information that can provide much needed and helpful data for years to come.