Inflow (hydrology)

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Torrente Pescone, one of the inflows of Lake Orta (Italy). Pescone alla foce.jpg
Torrente Pescone, one of the inflows of Lake Orta (Italy).

In hydrology, the inflow of a body of water is the source of the water in the body of water. It can also refer to the average volume of incoming water in unit time. It is contrasted with outflow.

Hydrology The science of the movement, distribution, and quality of water on Earth and other planets

Hydrology is the scientific study of the movement, distribution, and quality of water on Earth and other planets, including the water 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. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management.

Body of water Any significant accumulation of water, generally on a planets surface

A body of water or waterbody is any significant accumulation of water, generally on a planet's surface. The term most often refers to oceans, seas, and lakes, but it includes smaller pools of water such as ponds, wetlands, or more rarely, puddles. A body of water does not have to be still or contained; rivers, streams, canals, and other geographical features where water moves from one place to another are also considered bodies of water.

Water chemical compound

Water is a transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms. It is vital for all known forms of life, even though it provides no calories or organic nutrients. Its chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Water is the name of the liquid state of H2O at standard ambient temperature and pressure. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds are formed from suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.



All bodies of water have multiple inflows, but often, one inflow may predominate and be the largest source of water. However, in many cases, no single inflow will predominate and there will be multiple primary inflows. For a lake, the inflow may be a river or stream that literally flows into the lake. Inflow may also be, strictly speaking, not flows, but rather precipitation, like rain.

Lake A body of relatively still water, in a basin surrounded by land

A lake is an area filled with water, localized in a basin, that is surrounded by land, apart from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, and therefore are distinct from lagoons, and are also larger and deeper than ponds, though there are no official or scientific definitions. Lakes can be contrasted with rivers or streams, which are usually flowing. Most lakes are fed and drained by rivers and streams.

River Natural flowing watercourse

A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague.

Stream A body of surface water flowing down a channel

A stream is a body of water with surface water flowing within the bed and banks of a channel. The stream encompasses surface and groundwater fluxes that respond to geological, geomorphological, hydrological and biotic controls.

Inflow can also be used to refer to groundwater recharge.

Groundwater recharge groundwater that recharges an aquifer

Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer. This process usually occurs in the vadose zone below plant roots and, is often expressed as a flux to the water table surface. Groundwater recharge also encompasses water moving away from the water table farther into the saturated zone. Recharge occurs both naturally and through anthropogenic processes, where rainwater and or reclaimed water is routed to the subsurface.

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Estuary A partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea

An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea.

Lagoon A shallow body of water separated from a larger body of water by barrier islands or reefs

A lagoon is a shallow body of water separated from a larger body of water by barrier islands or reefs. Lagoons are commonly divided into coastal lagoons and atoll lagoons. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries. Lagoons are common coastal features around many parts of the world.

Evaporite A water-soluble mineral sediment formed by evaporation from an aqueous solution

Evaporite is the term for a water-soluble mineral sediment that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as ocean deposits, and non-marine, which are found in standing bodies of water such as lakes. Evaporites are considered sedimentary rocks and are formed by chemical sediments.

The twelve leverage points to intervene in a system were proposed by Donella Meadows, a scientist and system analyst focused on environmental limits to economic growth.

Endorheic basin Closed drainage basin that allows no outflow

An endorheic basin is a limited drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but converges instead into lakes or swamps, permanent or seasonal, that equilibrate through evaporation. Such a basin may also be referred to as a closed or terminal basin or as an internal drainage system or interior drainage basin.

Crater lake Lake formed within a (usually volcanic) crater

A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite, or in the crater left by an artificial explosion caused by humans. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not made. Crater lakes covering active (fumarolic) volcanic vents are sometimes known as volcanic lakes, and the water within them is often acidic, saturated with volcanic gases, and cloudy with a strong greenish color. For example, the crater lake of Kawah Ijen in Indonesia has a pH of under 0.5. Lakes located in dormant or extinct volcanoes tend to have fresh water, and the water clarity in such lakes can be exceptional due to the lack of inflowing streams and sediment.

River source The starting point of a river

The source or headwaters of a river or stream is the furthest place in that river or stream from its estuary or confluence with another river, as measured along the course of the river.

In hydrology, discharge is the volumetric flow rate of water that is transported through a given cross-sectional area. It includes any suspended solids (e.g. sediment), dissolved chemicals (e.g. CaCO3(aq)), or biologic material (e.g. diatoms) in addition to the water itself.

Kukkarahalli Lake lake in India

Kukkarahalli Lake also called Kukkarhalli Kere, located in the heart of the Mysore city, adjoins the Manasgangotri, the Kalamandir (Rangyana) and the Central Food Technological Research Institute (CFTRI) campus. It provides lung-space to the city. Mummadi Krishnaraja Wodeyar, (1794–1868) of the Mysore Dynasty was responsible for getting the lake created, in the year 1864, to provide water for irrigation to about 4000 ha of land outside the city. The Lake also used to be a source of water supply to the city of Mysore but over the years, sewage and excessive land encroachments and blockage of water flow sources almost led to the eutrophication of the lake. The University of Mysore and the citizen forums of Mysore continue to make efforts to preserve the lake by implementing several remedial measures. There is a 4.5 km walkway on the periphery of the lake with shaded stone benches for visitors to sit, relax and enjoy the scenic serenity of the lake.

Kagera River river in Rwanda

The Kagera River, also Akagera River, or Alexandra Nile, is an East African river, forming part of the upper headwaters of the Nile and carrying water from its most distant source.

Lake retention time is a calculated quantity expressing the mean time that water spends in a particular lake. At its simplest, this figure is the result of dividing the lake volume by the flow in or out of the lake. It roughly expresses the amount of time taken for a substance introduced into a lake to flow out of it again. The retention time is especially important where pollutants are concerned.

The United States Environmental Protection Agency (EPA) Storm Water Management Model is a dynamic rainfall–runoff–subsurface runoff simulation model used for single-event to long-term (continuous) simulation of the surface/subsurface hydrology quantity and quality from primarily urban/suburban areas. It can simulate the Rainfall- runoff, runoff, evaporation, infiltration and groundwater connection for roots, streets, grassed areas, rain gardens and ditches and pipes, for example. The hydrology component of SWMM operates on a collection of subcatchment areas divided into impervious and pervious areas with and without depression storage to predict runoff and pollutant loads from precipitation, evaporation and infiltration losses from each of the subcatchment. Besides, low impact development (LID) and best management practice areas on the subcatchment can be modeled to reduce the impervious and pervious runoff. The routing or hydraulics section of SWMM transports this water and possible associated water quality constituents through a system of closed pipes, open channels, storage/treatment devices, ponds, storages, pumps, orifices, weirs, outlets, outfalls and other regulators. SWMM tracks the quantity and quality of the flow generated within each subcatchment, and the flow rate, flow depth, and quality of water in each pipe and channel during a simulation period composed of multiple fixed or variable time steps. The water quality constituents such as water quality constituents can be simulated from buildup on the subcatchments through washoff to a hydraulic network with optional first order decay and linked pollutant removal, best management practice and low-impact development removal and treatment can be simulated at selected storage nodes. SWMM is one of the hydrology transport models which the EPA and other agencies have applied widely throughout North America and through consultants and universities throughout the world. The latest update notes and new features can be found on the EPA website in the download section. Recently added in November 2015 were the EPA SWMM 5.1 Hydrology Manual and in 2016 the EPA SWMM 5.1 Hydraulic Manual and EPA SWMM 5.1 Water Quality Volume (III) + Errata

Open and closed lakes refer to the major subdivisions of lakes - bodies of water surrounded by land. Exorheic, or open lakes drain into a river, or other body of water that ultimately drains into the ocean. Endorheic basins fall into the category of endorheic or closed lakes, wherein waters do not drain into the ocean, but are reduced by evaporation, and/or drain into the ground.

Veeranam Lake lake in India

Veeranam Lake is located 14 km (8.7 mi) SSW in Cuddalore district in the state of Tamil Nadu in South India. It is located 1 km (0.62 mi) from Kattumannarkoil and 235 km (146 mi) from Chennai, India. It is one of the water reservoirs from where water is supplied to Chennai city. The lake has a capacity to store about 1,465 mcft of water. Though the level in the Veeranam lake has dipped to 323 million cubic feet (mcft), the same amount of 180 mld was being drawn for city supply.

Silver Lake is a 640-acre (2.6 km2) lake in Pembroke, Kingston, and Plympton, Massachusetts, south of Route 27 and east of Route 36. The Pembroke/Plympton town line is entirely within the lake, and a portion of the western shoreline of the lake is the town line with Halifax. It used to be called the Jones River Pond, but its name was changed to Silver Lake in the 1800s in a marketing effort to sell more ice from it. The lake is the principal water supply for the City of Brockton, whose water treatment plant is on Route 36 in Halifax. The inflow of the pond is Tubbs Meadow Brook, and the pond is the headwaters of the Jones River. Occasionally water is diverted into Silver Lake from Monponsett Pond in Halifax and Furnace Pond in Pembroke whenever there is a water shortage. Although the lake is a reservoir, which prevents recreational activities to keep the drinking water clean, the water from the diversions are not and can pump in contaminated water. Monponsett Pond in particular has reoccurring toxic algae growths which get transferred into the lake. It is supposed to be the main source of the Jones River by contributing aboot twenty percent of the river's flow, but the Forge Pond Dam near its base lets out minimal, some years no, water to the river. This also prevents migratory aquatic animals from reaching the lake. Brockton prefers to keep the dam to have more accessible water. Access to the pond is through Silver Lake Sanctuary, a 92-acre (370,000 m2) property where one can walk, hike and fish, which is located at the end of Barses Lane, off Route 27 in Kingston.

Inflow may refer to:

Caspian Sea lake in Asia and Europe, largest enclosed inland body of water on Earth

The Caspian Sea is the world's largest inland body of water, variously classed as the world's largest lake or a full-fledged sea. It is an endorheic basin located between Europe and Asia, to the east of the Caucasus Mountains and to the west of the broad steppe of Central Asia. The sea has a surface area of 371,000 km2 and a volume of 78,200 km3. It has a salinity of approximately 1.2%, about a third of the salinity of most seawater. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the west, Iran to the south, and Turkmenistan to the southeast. The Caspian Sea is home to a wide range of species and may be best known for its caviar and oil industries. Pollution from the oil industry and dams on rivers draining into the Caspian Sea have had negative effects on the organisms living in the sea.

River mouth end of a river

A river mouth is the part of a river where the river debouches into another river, a lake, a reservoir, a sea, or an ocean.


Infiltration/Inflow (I/I) causes dilution in sanitary sewers. Dilution of sewage decreases the efficiency of treatment, and may cause sewage volumes to exceed design capacity. Although inflow is technically different from infiltration, it may be difficult to determine which is causing dilution problems in inaccessible sewers. The United States Environmental Protection Agency defines the term infiltration/inflow as combined contributions from both.


    Wiktionary-logo-en-v2.svg The dictionary definition of inflow at Wiktionary