"Riverbed" redirects here. For other uses, see Riverbed (disambiguation).
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A woman digs in a dry stream bed in Kenya to find water during a drought.
A streambed or stream bed is the bottom of a stream or river (bathymetry) and is confined within a channel, or the banks (bank (geography) of the waterway.[1] Usually, the bed does not contain terrestrial (land) vegetation and instead supports different types of aquatic vegetation (aquatic plant), depending on the type of streambed material and water velocity. Streambeds are what would be left once a stream is no longer in existence. The beds are usually well preserved even if they get buried because the banks and canyons made by the stream are typically hard, although soft sand and debris often fill the bed. Dry, buried streambeds can actually be underground water pockets.[1] During times of rain, sandy streambeds can soak up and retain water, even during dry seasons, keeping the water table close enough to the surface to be obtainable by local people.[1]
A stream bed armored with rocks
The nature of any streambed is always a function of the flow dynamics and the local geologic materials. The climate of an area will determine the amount of precipitation a stream receives and therefore the amount of water flowing over the streambed. A streambed is usually a mix of particle sizes which depends on the water velocity and the materials introduced from upstream and from the watershed. Particle sizes can range from very fine silts and clays to large cobbles and boulders (grain size). In general, sands move most easily, and particles become more difficult to move as they increase in size. Silts and clays, although smaller than sands, can sometimes stick together, making them harder to move along the streambed.[2] In streams with a gravel bed, the larger grain sizes are usually on the bed surface with finer grain sizes below. This is called armoring of the streambed.[2][3][4]
The old bed of the Mississippi River near Kaskaskia, Illinois, left behind after the river shifted
The streambed is very complex in terms of erosion and deposition. As the water flows downstream, different sized particles get sorted to different parts of a streambed as water velocity changes and sediment is transported, eroded and deposited on the streambed.[5] Deposition usually occurs on the inside of curves, where water velocity slows, and erosion occurs on the outside of stream curves, where velocity is higher.[2] This continued erosion and deposition of sediment tends to create meanders of the stream. In streams with a low to moderate grade, deeper, slower water pools (stream pools) and faster shallow water riffles often form as the stream meanders downhill. Pools can also form as water rushes over or around obstructions in the waterway.[2]
Under certain conditions a river can branch from one streambed to multiple streambeds.[2] For example, an anabranch may form when a section of stream or river goes around a small island and then rejoins the main channel. The buildup of sediment on a streambed may cause a channel to be abandoned in favor of a new one (avulsion (river)). A braided river may form as small threads come and go within a main channel.[6]
^ abc"Below sandy, dry riverbeds: A medicine against drought". www.un-ihe.org. Retrieved 2023-06-08.
^ abcdeAllan, David (2009). Stream Ecology: Structure and Function of Running Waters (2nd ed.). Dordrecht, The Netherlands: Springer. pp. |pages=36-43. ISBN 9781402055829.
^Whiting, Peter J.; King, John G. (2003). "Surface particle sizes on armoured gravel streambeds: Effects of supply and hydraulics". Earth Surface Processes and Landforms. 28 (13): 1459–1471. Bibcode:2003ESPL...28.1459W. doi:10.1002/esp.1049.
^Wilcock, Peter R.; DeTemple, Brendan T. (2005). "Persistence of armor layers in gravel-bed streams". Geophysical Research Letters. 32 (8). Bibcode:2005GeoRL..32.8402W. doi:10.1029/2004GL021772. ISSN 0094-8276.
^Garcia, Marcelo; Parker, Gary (1991). "Entrainment of Bed Sediment into Suspension". Journal of Hydraulic Engineering. 117 (4): 414–435. doi:10.1061/(asce)0733-9429(1991)117:4(414).
^Jerolmack, Douglas J.; Mohrig, David (2007). "Conditions for branching in depositional rivers". Geology. 35 (5): 463. Bibcode:2007Geo....35..463J. doi:10.1130/G23308A.1. ISSN 0091-7613.
A streambed or streambed is the bottom of a stream or river (bathymetry) and is confined within a channel, or the banks (bank (geography) of the waterway...
A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a...
Indications of waterborne debris and sediment transport. Defined river or streambed and banks. The catchment area exceeds .25 square miles (0.65 km2). USGS...
Stream load is a geologic term referring to the solid matter carried by a stream (Strahler and Strahler, 2006). Erosion and bed shear stress continually...
Placer mining (/ˈplæsər/) is the mining of streambed (alluvial) deposits for minerals. This may be done by open-pit (also called open-cast mining) or...
The term bed load or bedload describes particles in a flowing fluid (usually water) that are transported along the streambed. Bed load is complementary...
pebbles, sand, silt, and clay. These particles make up the bed load of the stream. Stream competence was originally simplified by the “sixth-power-law...
the 'classic' chalk stream characteristics of alkaline, crystal-clear water, flowing consistently and equably over clean gravel beds. State of England's...
stream the width must be taken into consideration. The bankfull width is the distance across the bed at an average cross-section at the full-stream level...
sediment along a streambed and its banks; this will take rocks and particles from the banks and bed of the stream and add this to the stream's load. This process...
erosion or deposition on the river bed. The movement of water across the streambed exerts a shear stress directly onto the bed. If the cohesive strength of...
and cultural landscapes, for example: Serious erosion – scouring of the streambed, Subsequent landslips, Endangering of mountain forest and protected forest...
slope, flowing waters can alter the general shape or direction of the streambed, a characteristic also known as geomorphology. The profile of the river...
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...
during precipitation events. Many incised arroyos that are destructive to streambeds and adjacent man-made structures were formed as a result of drainage...
nearly level streambed and sluggishly moving water, that may be able to carry only small amounts of very fine sediment. High gradient streams tend to have...
through a stream-bed is: C b = K A b {\displaystyle C_{b}=K{\frac {A}{b}}} where C b {\displaystyle C_{b}} is the conductance of the stream-bed ([L2T−1];...
following the streambed of the springs that created the cavern. This trail includes the Rimstone Dams, which create pools along the streambed, and the Ghost...
Garden, English Rose Garden, and Garden of the Senses. A small lake and streambed attract various birds such as ducks, geese, coots, and herons. Over 300...
have braided stream patterns because of the deficiency of water and the abundance of sediments. Water percolates down into the streambed, causing an abrupt...
of Tank Stream over time. Brick drains, possibly dated pre 1820, were found. A further search revealed soil from the original Tank Streambed. The surviving...
[according to whom?] as it appears[where?] to be using the old Warche river streambed.[citation needed] The Eau Rouge has been a border river for several periods...
several other names, including stream, creek and brook. Their current is confined within a bed and stream banks. Streams play an important corridor role...
Louisiana Seabed, the floor of the ocean or ocean bottom Streambed, the channel bottom of a stream, river or creek The Bottom, capital of the island of Saba...
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