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Stream

earth science Maturity 7-9 Next article →

A stream is a continuous body of surface water flowing within the bed and banks of a channel.

Dranse de Montriond 09
Dranse de Montriond 09

These moving waters are essential components of the Earth's natural systems. They act as vital conduits within the water cycle to transport moisture across the landscape. Streams also serve as instruments for groundwater recharge by allowing water to sink into the earth. Furthermore, they function as biological corridors for fish and wildlife migration. The specific habitat located in the immediate vicinity of a stream is known as a riparian zone.

Bach Isenach
Bach Isenach

Maintaining these zones is critical for conserving biodiversity during the ongoing Holocene extinction event.

The flow of a stream is controlled by three distinct inputs. The first is surface runoff, which comes from precipitation like rain or from melting snow and ice.

creek in perisher
creek in perisher

This runoff often begins as a thin layer known as sheet wash. This layer then organizes into a network of tiny paths called rills. When these rills concentrate into a single channel, a stream is born. The second input is daylighted subterranean water. The third input is surfaced groundwater, which is often called spring water.

Potok pod jezerom 1
Potok pod jezerom 1

While surface and subterranean water levels change quickly with rainfall, groundwater remains relatively constant. Groundwater levels are instead controlled by long-term precipitation patterns.

Streams vary greatly in size, volume, and behavior, leading to many different names. A brook is a small, shallow stream that is often easily forded. It is frequently fed by a spring or a seep.

Parramattastream
Parramattastream

A creek is generally larger than a brook but smaller than a river. In places like the United States and Australia, a creek is often a minor tributary.

Stevens Creek Tributary A in Macon County, IL
Stevens Creek Tributary A in Macon County, IL

A river is a much larger natural stream that is wider and deeper. Rivers are often navigable by water craft and are not easily crossed on foot. Some streams are perennial, meaning they flow year-round. Others are intermittent or ephemeral, flowing only during certain times.

Streams also interact with one another through complex branching patterns. A tributary is a stream that flows into a larger parent river.

Gangi River, Arrah
Gangi River, Arrah

If two tributaries of similar size merge, their meeting point is called a confluence. This point can also be referred to as a fork. Conversely, a distributary is a channel that branches away from a main stream. This process is known as river bifurcation. Distributaries are common features in river deltas where a stream enters wide, flat lands or coastal plains.

Whites Creek from Road 313 bridge Douglas County, Missouri
Whites Creek from Road 313 bridge Douglas County, Missouri

They can also appear on alluvial fans or when a tributary splits near its confluence.

Different regions around the world use unique terminology to describe these watercourses. In the United Kingdom, the term "allt" is used in the Scottish Highlands. In Scotland and North East England, people use the word "burn." In Wales, the word "nant" is common.

In the United States, names vary by state. In Maryland and Virginia, streams are often called "branches." In Florida, "runs" are streams that emerge from natural springs. In New York and New Jersey, the Dutch-derived word "kill" refers to a riverbed or water channel.

Aubach (Wiehl) nahe dem Weiherdamm in Wildbergerhütte
Aubach (Wiehl) nahe dem Weiherdamm in Wildbergerhütte

These diverse names reflect the deep history of human interaction with local hydrology.

Physical features within a stream channel define its character and energy. The bottom of the channel is the stream bed. The deepest line through the channel is called the thalweg.

Low creek
Low creek

A stream might feature a knickpoint, which is a sudden change in the stream's gradient. When water flows over a knickpoint, it creates a waterfall or a cascade. This movement causes the stream to expend kinetic energy. Some sections of a stream may contain rapids, which are fast and turbulent.

Potok pod jezerom 1
Potok pod jezerom 1

Other sections might consist of a pool, where the water is deeper and moves more slowly.

Bluerock Creek, Alberta
Bluerock Creek, Alberta

There are also riffles, which are shallow and turbulent but less vigorous than rapids.

The study of these systems is a major field of science. The study of streams and waterways is known as surface hydrology. This is a core element of environmental geography. Hydrologists examine how water moves through the landscape and interacts with geological and biological controls. They monitor how drainage basins, also called watersheds, collect water into stream networks.

Profile surveys in 1914 in Umpqua River basin Oregon (1915) (14781997675)
Profile surveys in 1914 in Umpqua River basin Oregon (1915) (14781997675)

Understanding these processes helps scientists manage water resources and protect the diverse life that depends on them.

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🖼️ Images & Media (19)
File:Цврцка 2 PPRP001.jpg
Цврцка 2 PPRP001.jpg
File:Potok pod jezerom 1.jpg
Potok pod jezerom 1.jpg
File:Frozen stream Enäjärvi, Pori.JPG
Frozen stream Enäjärvi, Pori.JPG
File:Dranse de Montriond 09.jpg
Dranse de Montriond 09.jpg
File:Aubach (Wiehl) nahe dem Weiherdamm in Wildbergerhütte.jpg
Aubach (Wiehl) nahe dem Weiherdamm in...
Creek babbling through Benvoulin wetlands.webm
File:WymingBrook.jpg
WymingBrook.jpg
File:Parramattastream.jpg
Parramattastream.jpg
File:Bach Isenach.jpg
Bach Isenach.jpg
File:Stevens Creek Tributary A in Macon County, IL.jpg
Stevens Creek Tributary A in Macon County, IL.jpg
File:Homesteadcreekflowers.jpg
Homesteadcreekflowers.jpg
File:creek in perisher.jpg
creek in perisher.jpg

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