waterdepth

Waterdepth, sometimes written as waterdepth in datasets, refers to the vertical distance from the water surface to the bottom of a body of water at a given location. It describes how deep the water is there and is a fundamental parameter in hydrography, oceanography, limnology, and coastal engineering. Depth is not fixed; it changes with time due to tides, river discharge, sedimentation, storm surge, and waves, while the bottom topography determines the maximum depth available in a region.

Depth is measured by hydrographic surveys using depth sounding methods. In open water, echo sounding with single-beam or multi-beam sonar is common; shallow areas may be mapped with airborne LiDAR; deeper regions are surveyed by vessels or autonomous vehicles. Measurements are referred to a vertical datum, such as chart datum or mean sea level, so depths can be compared across locations and times. Tidal changes mean the surface height varies; charts display depths relative to the datum and may include minimum or residual values.

Applications include nautical navigation to avoid shallow areas, dredging planning, offshore construction, and environmental and habitat studies. Bathymetry, the study of underwater depth, yields bathymetric maps and digital elevation models of the seafloor or lakebed, which are used in hydrodynamic modeling and resource management.

Variability and interpretation: depth values represent the bottom of the water column and are distinct from water column properties such as temperature, salinity, or turbidity. Charting and data products often include uncertainty estimates and metadata describing datum, precision, and coverage.