Bathymetric or Hydrographic… Which is it?

Bathymetric or Hydrographic… Which Is It?

Bathymetric or Hydrographic are both terms referring to submarine topography and are sometimes used interchangeably. Bathymetry is the foundation of the science of hydrography, which measures the physical features of a water body. Hydrography includes not only bathymetry, but also the shape and features of the shoreline; the characteristics of tides, currents, and waves; and the physical and chemical properties of the water itself.
At Vargo Associates, we perform hydrographic surveys to measure the depth and bottom configuration of water bodies. Collected data may be used for:

• Developing hydrographic models for floodplain analysis
• Helping marina owners plan for dredging and dock maintenance activities
• Assisting riparian land owners with dock and bulkhead permit applications

Vargo’s team of survey specialists utilizes specialized equipment on small survey vessels to determine the geography of a body of water, including the depth, tide measurements, shoreline obstacles, and physical features of the submarine topography. Most of the time, we deploy a small boat with a dual-frequency Echo Sounder connected to a ruggedized tablet and GPS receiver via bluetooth. The Echo Sounder acts as type of SONAR, determining water depth by transmitting sound pulses. The GPS receiver provides the horizontal position of the Echo Sounder to the tablet, and the tablet provides a map for the survey technicians to navigate project limits in accordance with the project scope.
Sometimes, for small projects, this survey can be performed with chest waders, a prism pole in the stream or pond, and a robotic total station along the bank collecting the observations. This data is then processed in the office using HYPACK® software and delivered to the client in an AutoCAD format, referenced to either the observed mean low water or a local tide station on NGVD 1929 or NAVD 1988.
Vargo Associates are members of the The Hydrographic Society of America (THSOA) and the National Society of Professional Surveyors (NSPS). To learn more about our firm, discover the Vargo Difference here or request an estimate, call 856.694.1716 today.