It is the branch of surveying which deals with any body of still or running water such as a lake, harbor, stream or river. Hydrographic surveys are used to define shore line and under water features.
Objectives of Hydrographic Surveying:
Hydro-graphic surveying are carried out for one or more of the following activities.
- 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.
- 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.
- 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.
Why we need Hydrographic Surveys - Uses & Applications of Hydrographic Survey
- Offshore engineering and the shipping industry have continued to expand.
- Drilling rigs (extracting oil, gas etc from deep sea) locating up to 125miles offshore, search for resources particularly oil and gas.
- Offshore islands are constructed of dredged material (to bring material form some where and dump there) to support marine structure.
- Harbor depth up to 80 is required to accommodate larger ships and tankers.
- Containerization has become an efficient and preferred method of cargo handling.
- The demand for recreational transportation ranges form large pleasure cruise ships to small sail bonds.
- 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)