Hydrography

Hydrography, a branch of hydrology, which deals with the description of the waters of the Earth—oceans, seas, lakes, rivers, etc. The collection of hydrographic material is carried out through horizontal and vertical surveys, depth measurements, determination of water level fluctuations, direction, velocities, and strength of currents, study of the bottom and shores of the body of water or water flow, physical and chemical properties of water, flora and fauna of the waters. As a result of these works, data of great sanitary importance are obtained regarding the distribution of waters, the size and form of water reserves, the level of standing water, the nature of water movement, currents, waves, tides, the geological composition of the water bed and the direction of existing geological processes, sediments, the composition and properties of water, its salinity, temperature, color, transparency, the type of plankton, bottom flora and fauna, fish resources, etc. The totality of this material characterizes the object being studied and its individual features.