Rivers Of Lee County, Texas
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A river is a natural flowing watercourse, usually
freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
, 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
creek A creek in North America and elsewhere, such as Australia, is a stream that is usually smaller than a river. In the British Isles it is a small tidal inlet. Creek may also refer to: People * Creek people, also known as Muscogee, Native Americans ...
,
brook A brook is a small river or natural stream of fresh water. It may also refer to: Computing *Brook, a programming language for GPU programming based on C *Brook+, an explicit data-parallel C compiler * BrookGPU, a framework for GPGPU programm ...
, 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 A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, 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. Rivers are part of the water cycle. Water generally collects in a river from precipitation through a drainage basin from
surface runoff Surface runoff (also known as overland flow) is the flow of water occurring on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when th ...
and other sources such as groundwater recharge,
springs Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a he ...
, and the release of stored water in natural ice and snowpacks. Rivers are often considered major features within a landscape; however, they actually only cover around 0.1% of the land on Earth. They are made more obvious and significant to humans since many human cities and civilizations are built around the freshwater supplied by rivers and streams. Most of the major cities of the world are situated on the banks of rivers, as they are, or were, used as a source of water, for obtaining food, for transport, as borders, as a defensive measure, as a source of hydropower to drive machinery, for bathing, and as a means of disposing of waste. In the pre-industrial era, larger rivers were a major obstruction to the movement of people, goods, and armies across them. Towns often developed at the few locations they could be crossed. Many major cities such as London are located at the lowest point at which a river could be bridged. Potamology is the scientific study of rivers, while limnology is the study of inland waters in general.


Topography


Source and drainage basin

A river begins at a source (or more often several sources) which is usually a
watershed Watershed is a hydrological term, which has been adopted in other fields in a more or less figurative sense. It may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, called a "watershe ...
, drains all the streams in its drainage basin, follows a watercourse, and ends either at a
mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...
or mouths which could be a
confluence In geography, a confluence (also: ''conflux'') occurs where two or more flowing bodies of water join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); o ...
, river delta, etc. The water in a river is usually confined to a channel, made up of a
stream bed A stream bed or streambed is the bottom of a stream or river (bathymetry) or the physical confine of the normal water flow (Channel (geography), channel). The lateral confines or channel margins are known as the stream Bank (geography), banks ...
between banks. In larger rivers there is often also a wider floodplain shaped by flood-waters over-topping the channel. Floodplains may be very wide in relation to the size of the river channel. This distinction between river channel and floodplain can be blurred, especially in urban areas where the floodplain of a river channel can become greatly developed by housing and industry. The term upriver (or upstream) refers to the direction towards the source of the river, i.e. against the direction of
flow Flow may refer to: Science and technology * Fluid flow, the motion of a gas or liquid * Flow (geomorphology), a type of mass wasting or slope movement in geomorphology * Flow (mathematics), a group action of the real numbers on a set * Flow (psych ...
. Likewise, the term downriver (or downstream) describes the direction towards the mouth of the river, in which the current flows. The term left bank refers to the left bank in the direction of flow, right bank to the right in the direction of flow.


Channels

Rivers can flow down mountains, through valleys or along plains, and can create
canyon A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tenden ...
s or gorges. The river channel typically contains a single stream, but some rivers flow as several interconnecting streams, producing a
braided river A braided river, or braided channel, consists of a network of river channels separated by small, often temporary, islands called braid bars or, in English usage, ''aits'' or ''eyots''. Braided streams tend to occur in rivers with high sediment l ...
. Braided rivers occur on peneplains and some of the larger river deltas. Anastamosing rivers are similar to braided rivers and are quite rare; they have multiple sinuous channel - 1 carrying large volumes of sediment. There are rare cases of river bifurcation in which a river divides, and the resultant flows end in different seas. An example is the
Nerodime River The Nerodime ( sq, Nerodimja or Nerodime; sr-cyr, Неродимка) is a river in the Nerodime region of Kosovo, a 41 km-long left tributary to the Lepenc river. It represents Europe's only instance of a river bifurcation flowing into tw ...
in Kosovo. A river flowing in its channel is a source of energy that acts on the river channel to change its shape and form. In 1757, German hydrologist Albert Brahms empirically observed that the submerged weight of objects that may be carried away by a river is proportional to the sixth power of the river flow speed. This formulation is also sometimes called Airy's law. Thus, if the speed of flow is doubled, the flow would dislodge objects with 64 times as much submerged weight. In mountainous torrential zones, this can be seen as erosion channels through hard rocks and the creation of sands and gravels from the destruction of larger rocks. A river valley that was created from a U-shaped glaciated valley can often easily be identified by the V-shaped channel that it has carved. In the middle reaches where a river flows over flatter land, meanders may form through erosion of the river banks and deposition on the inside of bends. Sometimes the river will cut off a loop, shortening the channel and forming an
oxbow lake An oxbow lake is a U-shaped lake or pool that forms when a wide meander of a river is cut off, creating a free-standing body of water. In South Texas, oxbows left by the Rio Grande are called '' resacas''. In Australia, oxbow lakes are call ...
or billabong. Rivers that carry large amounts of sediment may develop conspicuous deltas at their mouths. Rivers whose mouths are in saline tidal waters may form estuaries. Throughout the course of the river, the total volume of water transported downstream will often be a combination of the free water flow together with a substantial volume flowing through sub-surface rocks and gravels that underlie the river and its floodplain (called the hyporheic zone). For many rivers in large valleys, this unseen component of flow may greatly exceed the visible flow.


Types and ratings

Rivers have been classified by many criteria including their topography, their
biotic Biotics describe living or once living components of a community; for example organisms, such as animals and plants. Biotic may refer to: *Life, the condition of living organisms *Biology, the study of life * Biotic material, which is derived from ...
status, and their relevance to white water rafting or canoeing activities.


Subsurface rivers: subterranean and subglacial

Most but not all rivers flow on the surface. Subterranean rivers flow underground in caves. Such rivers are frequently found in regions with limestone geologic formations.
Subglacial stream Subglacial streams are conduits of glacial meltwater that flow at the base of glaciers and ice caps.
Hooke, Roger LeB. ...
s are the braided rivers that flow at the beds of glaciers and ice sheets, permitting meltwater to be discharged at the front of the glacier. Because of the gradient in pressure from the overlying weight of the glacier, such streams can even flow uphill.


Permanence of flow: perennial and ephemeral

An intermittent river (or ephemeral river) only flows occasionally and can be dry for several years at a time. These rivers are found in regions with limited or highly variable rainfall, or can occur because of geologic conditions such as a highly permeable river bed. Some ephemeral rivers flow during the summer months but not in the winter. Such rivers are typically fed from chalk aquifers which recharge from winter rainfall. In England these rivers are called ''bournes'' and give their name to places such as
Bournemouth Bournemouth () is a coastal resort town in the Bournemouth, Christchurch and Poole council area of Dorset, England. At the 2011 census, the town had a population of 183,491, making it the largest town in Dorset. It is situated on the Southern ...
and Eastbourne. Even in humid regions, the location where flow begins in the smallest tributary streams generally moves upstream in response to precipitation and downstream in its absence or when active summer vegetation diverts water for evapotranspiration. Normally dry rivers in arid zones are often identified as
arroyos Arroyo often refers to: * Arroyo (creek), an intermittently dry creek Arroyo may also refer to: People * Arroyo (surname) Places United States ;California * Arroyo Burro Beach, a public beach park in Santa Barbara County, California * Arroyo ...
or other regional names. The meltwater from large hailstorms can create a
slurry A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a centrifugal pu ...
of water, hail and sand or soil, forming temporary rivers.


Stream order classification

The
Strahler Stream Order In mathematics, the Strahler number or Horton–Strahler number of a mathematical tree (graph theory), tree is a numerical measure of its branching complexity. These numbers were first developed in hydrology by and ; in this application, they ar ...
ranks rivers based on the connectivity and hierarchy of contributing tributaries. Headwaters are first order while the
Amazon River The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile. The headwaters of t ...
is twelfth order. Approximately 80% of the rivers in the world are of the first and second order. The ways in which a river's characteristics vary between its upper and lower course are summarized by the Bradshaw model. Power-law relationships between channel slope, depth, and width are given as a function of discharge by " river regime". In certain languages, distinctions are made among rivers based on their stream order. In French, for example, rivers that run to the sea are called ''fleuve'', while other rivers are called ''rivière''. For example, in Canada, the Churchill River in Manitoba is called ''la rivière Churchill'' as it runs to
Hudson Bay Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...
, but the Churchill River in Labrador is called ''le fleuve Churchill'' as it runs to the Atlantic Ocean. As most rivers in France are known by their names only without the word ''rivière'' or ''fleuve'' (e.g. ''la
Seine ) , mouth_location = Le Havre/Honfleur , mouth_coordinates = , mouth_elevation = , progression = , river_system = Seine basin , basin_size = , tributaries_left = Yonne, Loing, Eure, Risle , tributarie ...
'', not ''le fleuve Seine'', even though the Seine is classed as a ''fleuve''), one of the most prominent rivers in the Francophone commonly known as ''fleuve'' is ''le fleuve Saint-Laurent'' (the St. Lawrence River). Since many ''fleuves'' are large and prominent, receiving many tributaries, the word is sometimes used to refer to certain large rivers that flow into other ''fleuves''; however, even small streams that run to the sea are called ''fleuve'' (e.g. '' fleuve côtier'', "coastal ''fleuve''").


Topographical classification

Rivers can generally be classified as either alluvial,
bedrock In geology, bedrock is solid Rock (geology), rock that lies under loose material (regolith) within the crust (geology), crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface mater ...
, or some mix of the two. Alluvial rivers have channels and floodplains that are self-formed in unconsolidated or weakly consolidated sediments. They erode their banks and deposit material on bars and their floodplains. Bedrock rivers form when the river downcuts through the modern sediments and into the underlying bedrock. This occurs in regions that have experienced some kind of uplift (thereby steepening river gradients) or in which a particularly hard
lithology The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lit ...
causes a river to have a steepened reach that has not been covered in modern alluvium. Bedrock rivers very often contain alluvium on their beds; this material is important in eroding and sculpting the channel. Rivers that go through patches of bedrock and patches of deep alluvial cover are classified as mixed bedrock-alluvial. Alluvial rivers can be further classified by their channel pattern as meandering, braided, wandering, anastomose, or straight. The morphology of an alluvial river reach is controlled by a combination of sediment supply, substrate composition, discharge, vegetation, and bed aggradation.


Biotic classification

There are several systems of classification based on ecological conditions typically assigning classes from the most oligotrophic or unpolluted through to the most eutrophic or polluted. Other systems are based on a whole eco-system approach such as developed by the New Zealand Ministry for the Environment. In Europe, the requirements of the Water Framework Directive has led to the development of a wide range of classification methods including classifications based on fishery status A system of river zonation used in francophone communities divides rivers into three primary zones: * The ''crenon'' is the uppermost zone at the source of the river. It is further divided into the eucrenon (spring or boil zone) and the hypocrenon (brook or headstream zone). These areas have low temperatures, reduced oxygen content and slow moving water. * The ''rhithron'' is the upstream portion of the river that follows the crenon. It has relatively cool temperatures, high oxygen levels, and fast, turbulent, swift flow. * The ''potamon'' is the remaining downstream stretch of river. It has warmer temperatures, lower oxygen levels, slow flow and sandier bottoms.


Navigability

The international scale of river difficulty is used to rate the challenges of navigation—particularly those with
rapids Rapids are sections of a river where the river bed has a relatively steep gradient, causing an increase in water velocity and turbulence. Rapids are hydrological features between a ''run'' (a smoothly flowing part of a stream) and a ''cascade''. ...
. Class I is the easiest and Class VI is the hardest.


Streamflow

Studying the flows of rivers is one aspect of hydrology.


Characteristics


Direction

Rivers flow downhill with their power derived from gravity. A common misconception holds that all or most rivers flow from north to south, but this is not so: rivers flow in all directions of the compass and often have complex meandering paths. Rivers flowing downhill, from river source to river mouth, do not necessarily take the shortest path. For alluvial streams, straight and braided rivers have very low sinuosity and flow directly down hill, while meandering rivers flow from side to side across a valley. Bedrock rivers typically flow in either a
fractal In mathematics, a fractal is a geometric shape containing detailed structure at arbitrarily small scales, usually having a fractal dimension strictly exceeding the topological dimension. Many fractals appear similar at various scales, as illu ...
pattern, or a pattern that is determined by weaknesses in the bedrock, such as faults, fractures, or more erodible layers.


Rate

Volumetric flow rate In physics and engineering, in particular fluid dynamics, the volumetric flow rate (also known as volume flow rate, or volume velocity) is the volume of fluid which passes per unit time; usually it is represented by the symbol (sometimes ). I ...
, also known as discharge, volume flow rate, and rate of water flow, is the volume of water which passes through a given cross-section of the river channel per unit time. It is typically measured in cubic metres per second (cumec) or cubic feet per second (cfs). Volumetric flow rate can be thought of as the mean velocity of the flow through a given cross-section, times that cross-sectional area. Mean velocity can be approximated through the use of the law of the wall. In general, velocity increases with the depth (or hydraulic radius) and slope of the river channel, while the cross-sectional area scales with the depth and the width: the double-counting of depth shows the importance of this variable in determining the discharge through the channel.


Effects


Fluvial erosion

In its youthful stage, a river causes erosion in the watercourse, deepening the valley. Hydraulic action loosens and dislodges aggregate which further erodes the banks and the river bed. Over time, this deepens the river bed and creates steeper sides which are then weathered. The steepened nature of the banks causes the sides of the valley to move downslope causing the valley to become
V-shaped Many shapes have metaphorical names, i.e., their names are metaphors: these shapes are named after a most common object that has it. For example, "U-shape" is a shape that resembles the letter U, a Gaussian function, bell-shaped curve has the shap ...
. Waterfalls also form in the youthful river valley where a band of hard rock overlays a layer of soft rock. Differential erosion occurs as the river erodes the soft rock more readily than the hard rock, this leaves the hard rock more elevated and stands out from the river below. A plunge pool forms at the bottom and deepens as a result of hydraulic action and abrasion.


Flooding

Flooding is a natural part of a river's cycle. The majority of the erosion of river channels and the erosion and deposition on the associated floodplains occur during the flood stage. In many developed areas, human activity has changed the form of river channels, altering magnitudes and frequencies of flooding. Some examples of this are the building of levees, the straightening of channels, and the draining of natural wetlands. In many cases human activities in rivers and floodplains have dramatically increased the risk of flooding. Straightening rivers allows water to flow more rapidly downstream, increasing the risk of flooding places further downstream. Building on flood plains removes flood storage, which again exacerbates downstream flooding. The building of levees only protects the area behind the levees and not those further downstream. Levees and flood-banks can also increase flooding upstream because of the back-water pressure as the river flow is impeded by the narrow channel banks. Detention basins finally also reduce the risk of flooding significantly by being able to take up some of the flood water.


Sediment yield

Sediment yield is the total quantity of particulate matter (suspended or bedload) reaching the outlet of a drainage basin over a fixed time frame. Yield is usually expressed as kilograms per square kilometre per year. Sediment delivery processes are affected by a myriad of factors such as drainage area size, basin slope, climate, sediment type (lithology), vegetation cover, and human land use / management practices. The theoretical concept of the 'sediment delivery ratio' (ratio between yield and total amount of sediment eroded) indicates that not all of the sediment is eroded within a certain catchment that reaches out to the outlet (e.g., deposition on floodplains). Such storage opportunities are typically increased in catchments of larger size, thus leading to a lower yield and sediment delivery ratio.


Brackish water

Brackish water occurs in most rivers where they meet the sea. The extent of brackish water may extend a significant distance upstream, especially in areas with high tidal ranges.


Ecosystem


River biota

The organisms in the riparian zone respond to changes in river channel location and patterns of flow. The ecosystem of rivers is generally described by the river continuum concept, which has some additions and refinements to allow for dams and waterfalls and temporary extensive flooding. The concept describes the river as a system in which the physical parameters, the availability of food particles and the composition of the ecosystem are continuously changing along its length. The food (energy) that remains from the upstream part is used downstream. The general pattern is that the first order streams contain particulate matter (decaying leaves from the surrounding forests) which is processed there by shredders like
Plecoptera Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the mo ...
larvae. The products of these shredders are used by collectors, such as
Hydropsychidae The Hydropsychidae are a family-level taxon consisting of net-spinning caddisflies. Hydropsychids are common among much of the world's streams, and a few species occupy the shorelines of freshwater lakes. Larvae of the hydropsychids construct ...
, and further downstream algae that create the primary production become the main food source of the organisms. All changes are gradual and the distribution of each species can be described as a normal curve, with the highest density where the conditions are optimal. In rivers
succession Succession is the act or process of following in order or sequence. Governance and politics *Order of succession, in politics, the ascension to power by one ruler, official, or monarch after the death, resignation, or removal from office of ...
is virtually absent and the composition of the ecosystem stays fixed.


Chemistry

The chemistry of rivers is complex and depends on inputs from the atmosphere, the geology through which it travels and the inputs from man's activities. The chemical composition of the water has a large impact on the ecology of that water for both plants and animals and it also affects the uses that may be made of the river water. Understanding and characterizing river water chemistry requires a well designed and managed sampling and analysis.


Uses


Construction material

The coarse sediments,
gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is classifi ...
, and sand, generated and moved by rivers are extensively used in construction. In parts of the world this can generate extensive new lake habitats as gravel pits fill with water. In other circumstances it can destabilize the river bed, and the course of the river and cause severe damage to spawning fish populations which rely on stable gravel formations for egg laying. In upland rivers, rapids with whitewater or even waterfalls occur. Rapids are often used for recreation, such as whitewater kayaking.


Energy production

Fast flowing rivers and waterfalls are widely used as sources of energy, via watermills and hydroelectric plants. Evidence of watermills shows them in use for many hundreds of years, for instance in
Orkney Orkney (; sco, Orkney; on, Orkneyjar; nrn, Orknøjar), also known as the Orkney Islands, is an archipelago in the Northern Isles of Scotland, situated off the north coast of the island of Great Britain. Orkney is 10 miles (16 km) north ...
at
Dounby Click Mill Dounby Click Mill is a mill located on the Mainland of Orkney, in Scotland. It is the last of the horizontal or "Norse" watermills of Orkney still in working order. The mill is constructed with drystone walls and roofed with flagstones and turf ...
. Prior to the invention of
steam power A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be trans ...
, watermills for grinding cereals and for processing wool and other textiles were common across Europe. In the 1890s the first machines to generate power from river water were established at places such as
Cragside Cragside is a Victorian country house near the town of Rothbury in Northumberland, England. It was the home of William Armstrong, 1st Baron Armstrong, founder of the Armstrong Whitworth armaments firm. An industrial magnate, scientist, philanth ...
in Northumberland and in recent decades there has been a significant increase in the development of large scale power generation from water, especially in wet mountainous regions such as Norway.


Food source

Rivers have been a source of food since pre-history. They are often a rich source of fish and other edible aquatic life and are a major source of fresh water, which can be used for drinking and irrigation. Rivers help to determine the urban form of cities and neighborhoods, and their corridors often present opportunities for
urban renewal Urban renewal (also called urban regeneration in the United Kingdom and urban redevelopment in the United States) is a program of land redevelopment often used to address urban decay in cities. Urban renewal involves the clearing out of blighte ...
through the development of foreshoreways such as river walks. Rivers also provide an easy means of disposing of wastewater and, in much of the less developed world, other wastes.


Navigation and transport

Rivers have been used for navigation for thousands of years. The earliest evidence of navigation is found in the
Indus Valley civilization The Indus Valley Civilisation (IVC), also known as the Indus Civilisation was a Bronze Age civilisation in the northwestern regions of South Asia, lasting from 3300 BCE to 1300 BCE, and in its mature form 2600 BCE to 1900&n ...
, which existed in northwestern India around 3300 BC. Riverine navigation provides a cheap means of transport and is still used extensively on most major rivers of the world like the Amazon, the Ganges, the Nile, the Mississippi, and the
Indus The Indus ( ) is a transboundary river of Asia and a trans-Himalayan river of South and Central Asia. The river rises in mountain springs northeast of Mount Kailash in Western Tibet, flows northwest through the disputed region of Kashmir, ...
. In some heavily forested regions such as Scandinavia and Canada,
lumberjack Lumberjacks are mostly North American workers in the logging industry who perform the initial harvesting and transport of trees for ultimate processing into forest products. The term usually refers to loggers in the era (before 1945 in the Unite ...
s use rivers to float felled trees downstream to lumber camps for further processing, saving much effort and cost by transporting the huge heavy logs by natural means.


Political borders

Rivers have been important in determining political boundaries and defending countries. For example, the Danube was a long-standing border of the Roman Empire, and today it forms most of the border between Bulgaria and Romania. The Mississippi in North America and the Rhine in Europe are major east–west boundaries in those continents. The Orange and Limpopo Rivers in southern Africa form the boundaries between provinces and countries along their routes.


Sacred rivers

Sacred rivers and their reverence is a phenomenon found in several religions, especially religions in which nature is revered. For example, the Indian-origin religions of Buddhism, Hinduism, Jainism, and Sikhism revere and preserve groves, forests, trees,
mountains A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher th ...
and rivers as sacred. Among the most sacred rivers in Hinduism are the Ganges, Yamuna, and Sarasvati rivers. Other sacred rivers for Indian religions include the Rigvedic rivers, the Narmada, the Godavari, and the Kaveri rivers. The Vedas and Gita, the most sacred of
Hindu texts Hindu texts are manuscripts and voluminous historical literature which are related to any of the diverse traditions within Hinduism. A few of these texts are shared across these traditions and they are broadly considered Hindu scriptures. These ...
, were written on the banks of the Sarasvati river.


Management

Rivers are often managed or controlled to make them more useful or less disruptive to human activity. * Dams or weirs may be built to control the flow, store water, or extract energy. * Levees, known as dikes in Europe, may be built to prevent river water from flowing on floodplains or floodways. * Canals connect rivers to one another for water transfer or navigation. * River courses may be modified to improve navigation, or straightened to increase the flow rate. River management is a continuous activity as rivers tend to 'undo' the modifications made by people. Dredged channels silt up, sluice mechanisms deteriorate with age, levees and dams may suffer seepage or catastrophic failure. The benefits sought through managing rivers may often be offset by the social and economic costs of mitigating the bad effects of such management. As an example, in parts of the developed world, rivers have been confined within channels to free up flat flood-plain land for development. Floods can inundate such development at high financial cost and often with loss of life. Rivers are increasingly managed for habitat conservation, as they are critical for many aquatic and riparian plants, resident and migratory fishes, waterfowl, birds of prey, migrating birds, and many mammals.


Concerns

Man-made causes, such as the over-exploitation and pollution, are the biggest threats and concerns which are making rivers ecologically dead and drying up the rivers. Plastic pollution imposes threats on aquatic life and river ecosystems because of plastic's durability in the natural environment. Plastic debris may result in entanglement and ingestion by aquatic life such as turtles, birds, and fish, causing severe injury and death. Human livelihoods around rivers are also impacted by plastic pollution through direct damage to shipping and transport vessels, effects on tourism or real estate value, and the clogging of drains and other hydraulic infrastructure leading to increased flood risk.


See also

;Arts, entertainment, and media * " Old Man River" * ''
The Riverkeepers ''The Riverkeepers: Two Activists Fight to Reclaim Our Environment as a Basic Human Right'' (1997) is an academic work by John Cronin and Robert F. Kennedy, Jr., with the foreword by Al Gore Albert Arnold Gore Jr. (born March 31, 1948) is a ...
'' (book) ;General * Drought *
Fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...
* Reach (geography) *
Salt tide Salt tide is a phenomenon in which the lower course of a river, with its low altitude with respect to the sea level, becomes Seawater, salty when the discharge of the river is low during dry season, usually worsened by the result of astronomical h ...
* Water conflict ;Crossings * Bridge *
Ferry A ferry is a ship, watercraft or amphibious vehicle used to carry passengers, and sometimes vehicles and cargo, across a body of water. A passenger ferry with many stops, such as in Venice, Italy, is sometimes called a water bus or water taxi ...
* Ford (crossing) * Tunnel ;Habitats * Exposed riverine sediments * Riparian zone ;Lists * Lists of rivers * List of international border rivers *
List of rivers by continent This is a comprehensive list of lists of rivers, organized primarily by continent and country. General lists * List of drainage basins by area (including rivers, lakes, and endorheic basins) * List of largest unfragmented rivers * List of long ...
* List of rivers by discharge * List of rivers by length * List of waterways ;Transport * Barge * Raft * River transport * Riverboat * Sailing *
Steamboat A steamboat is a boat that is marine propulsion, propelled primarily by marine steam engine, steam power, typically driving propellers or Paddle steamer, paddlewheels. Steamboats sometimes use the ship prefix, prefix designation SS, S.S. or S/S ...
* Towpath * Yacht


References


Further reading

* * — a non-technical primer on the
geomorphology Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or n ...
and hydraulics of water. * {{Authority control Bodies of water Fluvial landforms Geomorphology Sedimentology Water streams