Bathymetry and Hydrography2021-01-20T11:11:22+00:00

3. Bathymetry and Hydrography

3.1 Hydrography

in contrast, involve the representation of the surface of the riverbed or seabed. The end-product is normally a navigational chart. In recent years this branch has become increasingly important with the development of the offshore oil industry. In this case, in addition to the production of charts, the surveyor may be required to position large structures such as oil production platforms. This type of operation would normally necessitate the use of ground and satellite electronic position-fixing equipment.

  1. Measurement of tides for sea coast work E.g. construction of sea defense works, harbors etc, for the establishment of leveling datam and for reducing sounding.
  2. Determination of bed depth, by soundings
    • For navigation
    • Location of rocks, sand bars, navigation light.
    • Fro location of under water works volumes of under water excavation etc.
    • In connection with irrigation and land drainage schemes.
  3. Determination of direction of current in connection with
    • The location of sewer any pipe or channel that carry waste water out falls.
    • Determination of area subject to silt and scour the eating of the place.
    • Fornication purposes.
    • Measurement of quantity of water and flow of water in connection of water schemes, Power scheme and flood controls.
  4. Offshore engineering and the shipping industry have continued to expand.
  5. Drilling rigs (extracting oil, gas etc from deep sea) locating up to 125miles offshore, search for resources particularly oil and gas.
  6. Offshore islands are constructed of dredged material (to bring material form some where and dump there) to support marine structure.
  7. Harbor depth up to 80 is required to accommodate larger ships and tankers.
  8. Containerization has become an efficient and preferred method of cargo handling.
  9. The demand for recreational transportation ranges from large pleasure cruise ships to small sail bonds.
  10. Cruise ships to small sail bonds. Hydro graphic surveys are made to a quire and present data on oceans, lakes and harbors. It comprises all surveys made for
    • The determination of shore lines, soundings (measurement of depth below the water level) characteristics of bottoms, areas subjected to Scouring and silting, depth available for navigation and velocity as well as characteristics of flow of water.
    • The location of lights rocks sand balls, buoys ( anything that floats on the surface of water)

3.2 Multibeam River bed scanning

multibeam echo sounder is a type of sonar that is used to map the seabed. Like other sonar systems, multibeam systems emit sound waves in a fan shape beneath a ship’s hull. The amount of time it takes for the sound waves to bounce off the seabed and return to a receiver is used to determine water depth. Unlike other sonars, multibeam systems use beamforming to extract directional information from the returning soundwaves, producing a swath of depth readings from a single ping.

During the past decade, the use of multibeam acoustic survey in hydrographic mapping has become increasingly common and accepted. Unlike single beam acoustic survey, Multibeam acoustic survey acquires bathymetric sounding across a swath of water bottom using a collection of acoustic beams, as opposed to a single beam, which ensonifies only the area directly below the depth sounder.

Our survey team is providing multibeam acoustic bathymetric surveys with a specific focus on delivering results to meet the standards of resolution, accuracy, and survey coverage and lead time requirement for every project. GSC carries out multibeam acoustic surveys by Teledyne multibeam echosounders. The multibeam echosounder will equip with RTK GPS base survey system for DGPS corrections. Surveys will also adopt manufactured motion reference unit MRU 333 to measure the precise pitch, roll, and heave of sonar. Our boat supports the deployment of multibeam echo sounders, as well as vibracore sampler, side-scan sonars, RTK GPS receivers, motion reference unit and sound velocity probe.

Key Benefits:Provide high-resolution bathymetry map and a backscatter image of the surveyed area

  • Fast data acquisition
  • Great data coverage


  • Dredging projects
  • Rivers, harbor, dam inspection surveys
  • Oilfield engineering
  • Oceanographic research projects
  • Environmental studies
  • Hazard surveys