The terms “Bathymetric” and “Hydrographic” both refer to the study of marine topography and are frequently used interchangeably; however, there is a distinction between bathymetric surveys and hydrographic surveys. While closely related, these methods serve distinct purposes in mapping and exploring the underwater landscape. 

Understanding the Relationship Between Bathymetry and Hydrography

Bathymetry is a crucial part of Hydrography, a branch of science that measures the physical features of a body of water. Although bathymetry originally meant how deep the ocean is compared to sea level, it now refers to the shape and depth of underwater landforms. 

Just like how topographic maps show the features of land, bathymetric maps show what the underwater landscape looks like; different land depths are shown using colors and lines called depth contours. Hydrography includes not only the underwater landforms but also features like the shape of the shoreline, the movements of tides and currents, and the properties of the water itself.

Bathymetric Surveys: Mapping the Underwater Terrain

Bathymetric surveys are a subset of hydrographic surveys that provide a detailed depiction of the underwater terrain by noting features like underwater mountains (seamounts), trenches, and valleys. At Cinquini & Passarino, Inc., we conduct bathymetric surveys using multibeam and singlebeam solar data to measure the depth variations. 

By emitting sound waves and measuring their return times, we can create detailed maps of the underwater terrain of rivers, lakes, reservoirs, tidal slough channels, inlets, bays, and offshore throughout the surf zone. There are a wide range of applications for bathymetric surveys, including:

  • Informing decisions about deep-sea mining potential and underwater resources.
  • Identifying habitats, biodiversity hotspots, and potential conservation areas.
  • Studying underwater geological formations, including volcanoes, fault lines, and mid-ocean ridges.
  • Dredging planning and maintenance. 
  • Ensuring safe navigation for watercraft by mapping underwater hazards and obstacles.
  • Monitoring changes in water depth, shoreline erosion, and subsea infrastructure such as pipelines and wellheads 
  • Measuring sediment thickness and composition.
  • Planning, designing, and assessing underwater infrastructure, such as bridges, tunnels, and cables.
  • Creating flood risk maps and models for river basins and coastal areas.

Hydrographic Surveys: Mapping the Total Underwater Environment

At its core, hydrography is the science of measuring and characterizing bodies of water and their surrounding environments. Hydrographic surveys provide a detailed and holistic view of various aspects of the water column, ranging from the depths of oceans and contours of shorelines to the water’s physical and chemical composition. 

Hydrographic surveys employ a range of cutting-edge technologies, such as multibeam sonar systems, singlebeam echo sounders, GPS, and inertial navigation systems. These tools work in harmony to gather data on water depths, seafloor morphology, and even underwater objects or hazards. Hydrographic surveys are commonly used for:

  • Ensuring safe navigation by providing up-to-date nautical charts and maps.
  • Identifying and charting navigational hazards like rocks, shoals, and shipwrecks.
  • Assisting in route planning for vessels and optimizing shipping routes.
  • Planning and designing ports, harbors, and coastal infrastructure.
  • Monitoring and guiding dredging activities to maintain waterway depths and remove sediment.
  • Locating and assessing potential drilling sites for offshore oil and gas exploration.
  • Monitoring subsea infrastructure, including pipelines and wellheads.
  • Studying and managing aquatic ecosystems, including habitats, water quality, and aquatic life.
  • Assessing the impact of pollution and climate change on water bodies.
  • Collecting data for climate change research, such as sea level rise and ocean temperature measurements.
  • Monitoring coastal erosion, sediment transport, and shoreline changes.
  • Mapping and modeling river and lake floodplains to assess flood risks and manage flood-prone areas.
  • Assessing fish populations, their habitats, and migration patterns.
  • Studying riverbeds and water flows for the planning and development of hydroelectric power projects.
  • Inspecting and maintaining underwater infrastructure, such as bridges, piers, and dams.
  • Planning and managing aquaculture operations, including fish farms and oyster beds.
  • Monitoring and maintaining underwater utility infrastructure, such as water supply pipelines and sewage outfalls.
  • Evaluating the potential environmental impact of development projects in water bodies.

Get Started On Your Project Today

In the fascinating world beneath the waves, hydrographic and bathymetric surveys play distinct yet interconnected roles. Hydrography captures the holistic nature of aquatic environments, encompassing everything from water properties to shoreline dynamics, while bathymetry offers crucial insights for navigation, construction, and scientific exploration. Together, these surveying methods help shape our understanding of the underwater world and guide a range of vital applications.

At Cinquini & Passarino, Inc. (C&P), we specialize in hydrography and offer a variety of hydrographic surveying services for a wide range of applications, including multibeam and singlebeam bathymetric surveys, sidescan and backscatter imagery surveys, sub-bottom profile surveys, magnetometer and gradiometer surveys, utility depth of burial surveys, seafloor classification, and more. 

Whether it’s marine construction support, maintenance dredging, or wetland restoration surveys, our multidisciplinary teams are well-equipped and experienced to meet your project goals while adhering to strict US Army Corps of Engineers (USACOE) and International Hydrographic Organization (IHO) survey accuracy standards. In addition, we seamlessly integrate bathymetric surveys with topographic data acquired above the waterline using vessel-based laser scanners (LiDAR) or terrestrial-based land surveying to provide a comprehensive model of the project site from the bottom of the seafloor to above the waterline. 

For more information, contact us today at (707) 542-6268 or send us a message through our online form