Wiktionary
n. 1 (context environmental sciences hydrology English) A notional column of water from the surface to the bottom in a natural setting, notable for the differences in physical and chemical properties at various depths. 2 (context deep-sea diving English) The zone in which ascent and descent occur.
Wikipedia
A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediments. Water columns are used chiefly for environmental studies evaluating the stratification or mixing (e.g., by wind-induced currents) of the thermal or chemically stratified layers in a lake, stream or ocean. Some of the common parameters analyzed in the water column are pH, turbidity, temperature, salinity, total dissolved solids, various pesticides, pathogens and a wide variety of chemicals and biota.
The concept of water column is quite important, since many aquatic phenomena are explained by the incomplete vertical mixing of chemical, physical or biological parameters. For example, when studying the metabolism of benthic organisms, it is the specific bottom layer concentration of available chemicals in the water column that is meaningful, rather than the average value of those chemicals throughout the water column.
Hydrostatic pressure can be analyzed by the height of a water column, which effectively yields the pressure at a given depth of the column.
The term water column is also commonly used in scuba diving to describe the area in which divers ascend and descend.
Usage examples of "water column".
Just ahead of him, Bladuid and two other Gold elvespresumably the rest of Ryence's high mages were also slipping from their horses, one bent almost in two by the torpidly-rising water column of a spell blast.
On each trip to the deeps he had seen the massive heating units that kept the water column of Blowhole liquid, but he had not taken much notice of them.
Then the blood, turned green by the light filtering of the water column, would flow backwards as the fish made a last desperate dash for safety.
Microseepage of primordial methane and the higher hydrocarbons must occur on the seabed, with absorption taking place through the water column.
Confused, it had swum up and down the water column, seeking lifeany lifethat would give it sustenance.
When they came closer, Maskull perceived that this water column was the continuation and termination of a flowing brook, which came down from the direction of the mountains.
Now the entire ville was flooded, the houses and buildings and barracks made of sun dried adobe brick were literally dissolving under the never ending rain from the gushing water column in the center of the ville.