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51-549: The Hinchinbrook Channel is a channel between the Australian mainland and Hinchinbrook Island . It runs for 44 km between Oyster Point , just south of Cardwell , and Lucinda in Far North Queensland . The Aboriginal name for the channel is Bolan Milbirmi. The Herbert River flows into the channel's southern point. The channel includes 164 km2 of mangrove swamps and 109 km2 of open water. The Hinchinbrook Channel

102-431: A strengthening of the water cycle (also called hydrologic cycle). This effect has been observed since at least 1980. One example is when heavy rain events become even stronger. The effects of climate change on the water cycle have important negative effects on the availability of freshwater resources, as well as other water reservoirs such as oceans , ice sheets , the atmosphere and soil moisture . The water cycle

153-483: A constant flux. Channel heads associated with hollows in steep terrain frequently migrate up and down hillslopes depending on sediment supply and precipitation. Natural channels are formed by fluvial process and are found across the Earth . These are mostly formed by flowing water from the hydrological cycle , though can also be formed by other fluids such as flowing lava can form lava channels . Channels also describe

204-471: A point where shear stress can overcome erosion resistance of the ground surface. Channel heads are often associated with colluvium , hollows and landslides . Overland flow is a primary factor in channel initiation where saturation overland flow deepens to increase shear stress and begin channel incision. Overland flows converge in topographical depressions where channel initiation begins. Soil composition, vegetation, precipitation, and topography dictate

255-413: A reservoir within the hydrologic cycle is the average time a water molecule will spend in that reservoir ( see table ). It is a measure of the average age of the water in that reservoir. Groundwater can spend over 10,000 years beneath Earth's surface before leaving. Particularly old groundwater is called fossil water . Water stored in the soil remains there very briefly, because it is spread thinly across

306-448: Is a biogeochemical cycle that involves the continuous movement of water on, above and below the surface of the Earth . The mass of water on Earth remains fairly constant over time. However, the partitioning of the water into the major reservoirs of ice , fresh water , salt water and atmospheric water is variable and depends on climatic variables . The water moves from one reservoir to another, such as from river to ocean , or from

357-420: Is a difference between low gradient streams (less than a couple of percent in gradient or slightly sloped) and high gradient streams (steeply sloped). A wide variety of stream channel types can be distinguished (e.g. braided rivers , wandering rivers, single-thread sinuous rivers etc.). During floods , water flow may exceed the capacity of the channel and flood waters will spill out of the channel and across

408-546: Is also estimated that the oceans supply about 90% of the evaporated water that goes into the water cycle. The Earth's ice caps, glaciers, and permanent snowpack stores another 24,064,000 km accounting for only 1.7% of the planet's total water volume. However, this quantity of water is 68.7% of all freshwater on the planet. Human activities can alter the water cycle at the local or regional level. This happens due to changes in land use and land cover . Such changes affect "precipitation, evaporation, flooding, groundwater, and

459-438: Is essential to life on Earth and plays a large role in the global climate system and ocean circulation . The warming of our planet is expected to be accompanied by changes in the water cycle for various reasons. For example, a warmer atmosphere can contain more water vapor which has effects on evaporation and rainfall . The underlying cause of the intensifying water cycle is the increased amount of greenhouse gases in

510-456: Is frequently called a canal , with the Panama Canal providing an example. The term not only includes the deep-dredged   ship-navigable parts of an estuary or river leading to port facilities, but also to lesser channels accessing boat port-facilities such as marinas . When dredged channels traverse bay mud or sandy bottoms, repeated dredging is often necessary because of

561-410: Is less dense. Due to the significant difference in density, buoyancy drives humid air higher. As altitude increases, air pressure decreases and the temperature drops (see Gas laws ). The lower temperature causes water vapor to condense into tiny liquid water droplets which are heavier than the air, and which fall unless supported by an updraft. A huge concentration of these droplets over a large area in

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612-451: Is powered from the energy emitted by the sun. This energy heats water in the ocean and seas. Water evaporates as water vapor into the air . Some ice and snow sublimates directly into water vapor. Evapotranspiration is water transpired from plants and evaporated from the soil. The water molecule H 2 O has smaller molecular mass than the major components of the atmosphere, nitrogen ( N 2 ) and oxygen ( O 2 ) and hence

663-634: Is protected within the Hinchinbrook Island National Park , the Great Barrier Reef Marine Park and the Great Barrier Reef World Heritage Area. Dugong feed and seek habitat in the sea grass patches along the channel seafloor. The channel is bordered by extensive, deltaic mangrove forests. The northern end resembles a bay, more than a narrow channel, with a width of 4 km. The residence time of

714-455: The evolution of land animals from fish ) and Xenophanes of Colophon (530 BCE). Warring States period Chinese scholars such as Chi Ni Tzu (320 BCE) and Lu Shih Ch'un Ch'iu (239 BCE) had similar thoughts. The idea that the water cycle is a closed cycle can be found in the works of Anaxagoras of Clazomenae (460 BCE) and Diogenes of Apollonia (460 BCE). Both Plato (390 BCE) and Aristotle (350 BCE) speculated about percolation as part of

765-404: The exobase , the lower limit of the exosphere , where the gases can then reach escape velocity , entering outer space without impacting other particles of gas. This type of gas loss from a planet into space is known as planetary wind . Planets with hot lower atmospheres could result in humid upper atmospheres that accelerate the loss of hydrogen. In ancient times, it was widely thought that

816-416: The hyporheic zone . Over time, the water returns to the ocean, to continue the water cycle. The ocean plays a key role in the water cycle. The ocean holds "97% of the total water on the planet; 78% of global precipitation occurs over the ocean, and it is the source of 86% of global evaporation". Important physical processes within the water cycle include (in alphabetical order): The residence time of

867-581: The valley bottom, floodplain or drainage area . Examples of rivers that are trapped in their channels: Grand Canyon and Black Canyon of the Gunnison . In a larger nautical context, as a geographical place name, the term channel is another word for strait , which is defined as a relatively narrow body of water that connects two larger bodies of water. In this nautical context, the terms strait , channel , sound , and passage are synonymous and usually interchangeable. For example, in an archipelago ,

918-499: The waterless surface features on Venus . Channel initiation refers to the site on a mountain slope where water begins to flow between identifiable banks. This site is referred to as the channel head and it marks an important boundary between hillslope processes and fluvial processes. The channel head is the most upslope part of a channel network and is defined by flowing water between defined identifiable banks. A channel head forms as overland flow and/or subsurface flow accumulate to

969-478: The 22nd verse that the Sun heats up water and sends it down as rain. By roughly 500 BCE, Greek scholars were speculating that much of the water in rivers can be attributed to rain. The origin of rain was also known by then. These scholars maintained the belief, however, that water rising up through the earth contributed a great deal to rivers. Examples of this thinking included Anaximander (570 BCE) (who also speculated about

1020-453: The Earth, and is readily lost by evaporation, transpiration, stream flow, or groundwater recharge. After evaporating, the residence time in the atmosphere is about 9 days before condensing and falling to the Earth as precipitation. The major ice sheets – Antarctica and Greenland – store ice for very long periods. Ice from Antarctica has been reliably dated to 800,000 years before present, though

1071-545: The amount and rate of overland flow. The composition of a soil determines how quickly saturation occurs and cohesive strength retards the entrainment of material from overland flows. Vegetation slows infiltration rates during precipitation events and plant roots anchor soil on hillslopes. Subsurface flow destabilizes soil and resurfaces on hillslopes where channel heads are often formed. This often results in abrupt channel heads and landslides. Hollows form due to concentrated subsurface flows where concentrations of colluvium are in

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1122-451: The atmosphere becomes visible as cloud , while condensation near ground level is referred to as fog . Atmospheric circulation moves water vapor around the globe; cloud particles collide, grow, and fall out of the upper atmospheric layers as precipitation . Some precipitation falls as snow, hail, or sleet, and can accumulate in ice caps and glaciers , which can store frozen water for thousands of years. Most water falls as rain back into

1173-449: The atmosphere replenishes the land with freshwater. The flow of liquid water and ice transports minerals across the globe. It also reshapes the geological features of the Earth, through processes including erosion and sedimentation . The water cycle is also essential for the maintenance of most life and ecosystems on the planet. Human actions are greatly affecting the water cycle. Activities such as deforestation , urbanization , and

1224-476: The atmosphere, which lead to a warmer atmosphere through the greenhouse effect . Fundamental laws of physics explain how the saturation vapor pressure in the atmosphere increases by 7% when temperature rises by 1 °C. This relationship is known as the Clausius-Clapeyron equation . While the water cycle is itself a biogeochemical cycle , flow of water over and beneath the Earth is a key component of

1275-506: The availability of freshwater for a variety of uses". Examples for such land use changes are converting fields to urban areas or clearing forests . Such changes can affect the ability of soils to soak up surface water. Deforestation has local as well as regional effects. For example it reduces soil moisture, evaporation and rainfall at the local level. Furthermore, deforestation causes regional temperature changes that can affect rainfall patterns. Aquifer drawdown or overdrafting and

1326-405: The average residence time is shorter. In hydrology, residence times can be estimated in two ways. The more common method relies on the principle of conservation of mass ( water balance ) and assumes the amount of water in a given reservoir is roughly constant. With this method, residence times are estimated by dividing the volume of the reservoir by the rate by which water either enters or exits

1377-457: The channel is roughly 50 days. This long period is due to the lack of mixing of water in creeks and mangrove forests with offshore water. There is little to no current in the channel. 18°23′02″S 146°11′35″E  /  18.384°S 146.193°E  / -18.384; 146.193 This North Queensland geography article is a stub . You can help Misplaced Pages by expanding it . Channel (geography) Channels are important for

1428-523: The cycling of other biogeochemicals. Runoff is responsible for almost all of the transport of eroded sediment and phosphorus from land to waterbodies . The salinity of the oceans is derived from erosion and transport of dissolved salts from the land. Cultural eutrophication of lakes is primarily due to phosphorus, applied in excess to agricultural fields in fertilizers , and then transported overland and down rivers. Both runoff and groundwater flow play significant roles in transporting nitrogen from

1479-554: The deeper course through a reef , sand bar , bay , or any shallow body of water. An example of a river running through a sand bar is the Columbia Bar —the mouth of the Columbia River . A stream channel is the physical confine of a stream ( river ) consisting of a bed and stream banks . Stream channels exist in a variety of geometries. Stream channel development is controlled by both water and sediment movement. There

1530-517: The earlier Aristotle, the Eastern Han Chinese scientist Wang Chong (27–100 AD) accurately described the water cycle of Earth in his Lunheng but was dismissed by his contemporaries. Up to the time of the Renaissance, it was wrongly assumed that precipitation alone was insufficient to feed rivers, for a complete water cycle, and that underground water pushing upwards from the oceans were

1581-435: The exchange of energy, which leads to temperature changes. When water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence the climate system . The evaporative phase of the cycle purifies water because it causes salts and other solids picked up during the cycle to be left behind. The condensation phase in

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1632-522: The extraction of groundwater are altering natural landscapes ( land use changes ) all have an effect on the water cycle. On top of this, climate change is leading to an intensification of the water cycle . Research has shown that global warming is causing shifts in precipitation patterns, increased frequency of extreme weather events, and changes in the timing and intensity of rainfall. These water cycle changes affect ecosystems , water availability , agriculture, and human societies. The water cycle

1683-413: The functionality of ports and other bodies of water used for navigability for shipping . Naturally, channels will change their depth and capacity due to erosion and deposition processes. Humans maintain navigable channels by dredging and other engineering processes. By extension, the term also applies to fluids other than water, e.g., lava channels . The term is also traditionally used to describe

1734-580: The global and regional level. These findings are a continuation of scientific consensus expressed in the IPCC Fifth Assessment Report from 2007 and other special reports by the Intergovernmental Panel on Climate Change which had already stated that the water cycle will continue to intensify throughout the 21st century. The effects of climate change on the water cycle are profound and have been described as an intensification or

1785-537: The land mass floated on a body of water, and that most of the water in rivers has its origin under the earth. Examples of this belief can be found in the works of Homer ( c.  800 BCE ). In Works and Days (ca. 700 BC), the Greek poet Hesiod outlines the idea of the water cycle: "[Vapour] is drawn from the ever-flowing rivers and is raised high above the earth by windstorm, and sometimes it turns to rain towards evening, and sometimes to wind when Thracian Boreas huddles

1836-406: The land surface and can seep back into surface-water bodies (and the ocean) as groundwater discharge or be taken up by plants and transferred back to the atmosphere as water vapor by transpiration . Some groundwater finds openings in the land surface and emerges as freshwater springs. In river valleys and floodplains , there is often continuous water exchange between surface water and ground water in

1887-575: The land to waterbodies. The dead zone at the outlet of the Mississippi River is a consequence of nitrates from fertilizer being carried off agricultural fields and funnelled down the river system to the Gulf of Mexico . Runoff also plays a part in the carbon cycle , again through the transport of eroded rock and soil. The hydrodynamic wind within the upper portion of a planet's atmosphere allows light chemical elements such as Hydrogen to move up to

1938-443: The main contributors to river water. Bartholomew of England held this view (1240 CE), as did Leonardo da Vinci (1500 CE) and Athanasius Kircher (1644 CE). The first published thinker to assert that rainfall alone was sufficient for the maintenance of rivers was Bernard Palissy (1580 CE), who is often credited as the discoverer of the modern theory of the water cycle. Palissy's theories were not tested scientifically until 1674, in

1989-511: The ocean or onto land, where the water flows over the ground as surface runoff . A portion of this runoff enters rivers, with streamflow moving water towards the oceans. Runoff and water emerging from the ground ( groundwater ) may be stored as freshwater in lakes. Not all runoff flows into rivers; much of it soaks into the ground as infiltration . Some water infiltrates deep into the ground and replenishes aquifers , which can store freshwater for long periods of time. Some infiltration stays close to

2040-420: The ocean to the atmosphere. The processes that drive these movements are evaporation , transpiration , condensation , precipitation , sublimation , infiltration , surface runoff , and subsurface flow. In doing so, the water goes through different forms: liquid, solid ( ice ) and vapor . The ocean plays a key role in the water cycle as it is the source of 86% of global evaporation. The water cycle involves

2091-424: The processes that drive the movement of water throughout the hydrosphere . However, much more water is "in storage" (or in "pools") for long periods of time than is actually moving through the cycle. The storehouses for the vast majority of all water on Earth are the oceans. It is estimated that of the 1,386,000,000 km of the world's water supply, about 1,338,000,000 km is stored in oceans, or about 97%. It

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2142-400: The product of the sediment load and bed Bukhara size is proportional to the product of discharge and channel slope. A term " navigable channel " is used as a nautical term to mean a lane for ship travel, frequently marked (cf. Buoy ) and sometimes dredged . Thoresen distinguishes few categories of channels, from A (suitable for day and night navigation with guaranteed fairway depth ) all

2193-475: The pumping of fossil water increase the total amount of water in the hydrosphere. This is because the water that was originally in the ground has now become available for evaporation as it is now in contact with the atmosphere. Since the middle of the 20th century, human-caused climate change has resulted in observable changes in the global water cycle. The IPCC Sixth Assessment Report in 2021 predicted that these changes will continue to grow significantly at

2244-462: The reservoir. Conceptually, this is equivalent to timing how long it would take the reservoir to become filled from empty if no water were to leave (or how long it would take the reservoir to empty from full if no water were to enter). An alternative method to estimate residence times, which is gaining in popularity for dating groundwater, is the use of isotopic techniques. This is done in the subfield of isotope hydrology . The water cycle describes

2295-514: The rivers run into the sea, yet the sea is not full; unto the place from whence the rivers come, thither they return again" ( Ecclesiastes 1:6-7 ). Furthermore, it was also observed that when the clouds were full, they emptied rain on the earth ( Ecclesiastes 11:3 ). In the Adityahridayam (a devotional hymn to the Sun God) of Ramayana , a Hindu epic dated to the 4th century BCE, it is mentioned in

2346-409: The thick clouds." In the ancient Near East , Hebrew scholars observed that even though the rivers ran into the sea, the sea never became full. Some scholars conclude that the water cycle was described completely during this time in this passage: "The wind goeth toward the south, and turneth about unto the north; it whirleth about continually, and the wind returneth again according to its circuits. All

2397-678: The unstable subsequent movement of benthic soils. Responsibility for monitoring navigability conditions of navigation channels to various port facilities varies, and the actual maintenance work is frequently performed by a third party. Storms, sea-states, flooding, and seasonal sedimentation adversely affect navigability . In the U.S., navigation channels are monitored and maintained by the United States Army Corps of Engineers (USACE), although dredging operations are often carried out by private contractors (under USACE supervision). USACE also monitors water quality and some remediation. This

2448-512: The water between islands is typically called a channel or passage . The English Channel is the strait between England and France. The channel form is described in terms of geometry (plan, cross-sections, profile) enclosed by the materials of its bed and banks. This form is under influence of two major forces: water discharge and sediment supply. For erodible channels the mutual dependence of its parameters may be qualitatively described by Lane's Principle (also known as Lane's relationship ):

2499-442: The water cycle. Aristotle correctly hypothesized that the sun played a role in the Earth's hydraulic cycle in his book Meteorology , writing "By it [the sun's] agency the finest and sweetest water is everyday carried up and is dissolved into vapor and rises to the upper regions, where it is condensed again by the cold and so returns to the earth.", and believed that clouds were composed of cooled and condensed water vapor. Much like

2550-400: The way to D with no navigational aids and only estimated depths provided to the shipmaster . With regard to the dredging , channels can be unrestricted (wide enough to accommodate 10-15 widths of a largest ship used in this channel, semi-restricted with limited dredging in shallow waters, and fully restricted , where the entire channel is dredged. The latter, entirely human-made, channel

2601-1260: Was first established under the Rivers and Harbors Act of 1899 and modified under acts of 1913, 1935, and 1938. For example, the USACE developed the Intracoastal Waterway , and has the Mississippi Valley Division responsible for the Mississippi River from the Gulf to Cairo, Illinois , the North Atlantic Division for New York Harbor and Port of Boston , and the South Pacific Division for Port of Los Angeles and Port of Long Beach . Waterways policing as well as some emergency spill response falls under United States Coast Guard jurisdiction, including inland channels serving ports like Saint Louis hundreds of miles from any coast. The various state or local governments maintain lesser channels, for example former Erie Canal . Hydrological cycle The water cycle (or hydrologic cycle or hydrological cycle )

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