Discharge (hydrology)
In hydrology, discharge is the volume rate of water flow, including any suspended solids (e.g. sediment), dissolved chemicals (e.g. CaCO3(aq)), or biologic material (e.g. diatoms), which is transported through a given cross-sectional area. Frequently, other terms synonymous with discharge are used to describe the volumetric flow rate of water and are typically discipline dependent. For example, a fluvial hydrologist studying natural river systems may define discharge as streamflow, whereas an engineer operating a reservoir system might define discharge as outflow, which is contrasted with inflow.
Theory and calculation
GH Dury and MJ Bradshaw are two hydrologists who devised models showing the relationship between discharge and other variables in a river. The Bradshaw model described how pebble size and other variables change from source to mouth; while Dury considered the relationships between discharge and variables such as slope and friction.
The units that are typically used to express discharge include m³/s (cubic meters per second), ft³/s (cubic feet per second or cfs) and/or acre-feet per day. For example, the average discharge of the Rhine river in Europe is 2,200 cubic metres per second (78,000 cu ft/s) or 190,000,000 cubic metres (150,000 acre·ft) per day.
Hydrology
Hydrology is the scientific study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability. A practitioner of hydrology is a hydrologist, working within the fields of earth or environmental science, physical geography, geology or civil and environmental engineering.
Hydrology subdivides into surface water hydrology, groundwater hydrology (hydrogeology), and marine hydrology. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage-basin management and water quality, where water plays the central role.
Oceanography and meteorology are not included because water is only one of many important aspects within those fields.
Hydrological research can inform environmental engineering, policy and planning.
The term hydrology comes from Greek: ὕδωρ, hydōr, "water"; and λόγος, logos, "study".
History
Hydrology has been a subject of investigation and engineering for millennia. For example, about 4000 BC the Nile was dammed to improve agricultural productivity of previously barren lands. Mesopotamian towns were protected from flooding with high earthen walls. Aqueducts were built by the Greeks and Ancient Romans, while the history of China shows they built irrigation and flood control works. The ancient Sinhalese used hydrology to build complex irrigation works in Sri Lanka, also known for invention of the Valve Pit which allowed construction of large reservoirs, anicuts and canals which still function.
Hydrology (album)
Hydrology is the second EP by Recoil, released January 25, 1988.
Hydrology was Alan Wilder's second Recoil release. The CD and cassette version included the first release, 1+2.
Wilder was unable to promote his new album because of the onset of (his band) Depeche Mode's Music for the Masses Tour. Wilder described the project at this stage as "an antidote to Depeche Mode in some ways; a way to alleviate the frustrations of always working within a pop format."
Re-release
The CD of Hydrology Plus 1+2 was re-released in 2007, again on Mute Records. The tracklisting and artwork remain the same.
Track listing
All music written by Alan Wilder.
Credits and personnel
Notes
Hydrology (agriculture)
Agricultural hydrology is the study of water balance components intervening in agricultural water management, especially in irrigation and drainage.
Water balance components
The water balance components can be grouped into components corresponding to zones in a vertical cross-section in the soil forming reservoirs with inflow, outflow and storage of water:
The general water balance reads:
and it is applicable to each of the reservoirs or a combination thereof.
In the following balances it is assumed that the water table is inside the transition zone.
Surface water balance
The incoming water balance components into the surface reservoir (S) are:
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