The hydrographic survey investigations consist of triangulation, coast lining on adjoining hinter land of the water mass, sounding operations, current observation of water at various depths, collection of water samples from various depths with its temperature, collection of sea bed sample, float observation to determine the direction and velocity of surface flow etc. The results of these investigations are presented by way of hydrographic charts. Such hydrographic charts give direct information on depth of overall water mass, contours, shore and land features and nature of bottom of water mass.

Scope of Hydrographic survey.

Hydrographic survey is required for various purposes such as Navigational, Engineering and Investigational. The Navigational purposes include location of safest navigational routes, surveys for coastal shipping and in land navigation, surveys for periodical maintenance of water ways, location of submerged dangers such as wrecks, rocks, sand bars, renovation canals for navigation purpose etc.

Engineering purpose includes, port development, water resource development, pre & post dredging surveys, calculation of quantity to be dredged, estimation of dredging cost, channel marking, estimation of breakwater construction, canal survey etc.

Investigational purposes include bottom sampling, bottom profile study, silt calculation and sedimentation effects, under-water contour depiction, study of tides and tidal stream, study of tidal effects on sea cost and estuary, designing and alignment fixation of breakwater, feasibility study for coastal Shipping, feasibility study of a lake for Tourism development Preliminary Survey and making Project Reports for the renovation of existing Navigation canals etc.

On conducting the hydrographic survey at reservoirs, it could be ascertained the actual quantity of water and present bottom profile of the reservoir. It could easily be found out how much capacity of reservoir is reduced due to the sedimentation of silt. The hydrographic survey at waterways can find out wherever the dredging is necessary and the quantity to be dredged. Hydrographic survey at various inland canals and lakes can find out the safest routes for boat service. Hydrographic survey is unavoidable for finding the area where minimum dredging is required, for fixing economical navigation routes.