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32-515: The Pinn is a suburban, outer west London river. It has dendritic headwaters , the furthest is considered its source – in Harrow Weald . Its confluence with Frays River makes it a tributary of the Colne . It is one of three principal rivers wholly in the historic county of Middlesex . The river runs through Pinner , the northern halves of Eastcote and Ruislip : the latter may be

64-434: A navigational context, if one were floating on a raft or other vessel in the main stream, this would be the side the tributary enters from as one floats past; alternately, if one were floating down the tributary, the main stream meets it on the opposite bank of the tributary. This information may be used to avoid turbulent water by moving towards the opposite bank before approaching the confluence. An early tributary

96-446: A basin they form centripetal or inland drainage pattern. A deranged drainage system is a drainage system in drainage basins where there is no coherent pattern to the rivers and lakes. These can form in areas with extensive limestone deposits, where surface streams can disappear into the groundwater via caves and subterranean drainage routes. They can also form in areas where there has been much geological disruption. A classic example

128-603: A central playa . An axial river existed in the Espanola Basin as early as 13 million years ago, reaching the Santo Domingo Basin by 6.9 million years ago. However, at this time, the river drained into a playa in the southern Albuquerque Basin where it deposited the Popotosa Formation . The upper reach of this river corresponded to the modern Rio Chama , but by 5 million years ago, an ancestral Rio Grande draining

160-504: A central high point. Volcanos usually have archetypal features on which this commonly develops are modest or hard domes pattern develops when streams flow in many general directions (meaning quite long-term) In India, the Amarkantak range and Ramgarh crater are most archetypal; and Dogu'a Tembien in Ethiopia . When the streams converge at a point, which is generally a depression or

192-444: A larger stream ( main stem or "parent" ), river, or a lake . A tributary does not flow directly into a sea or ocean . Tributaries, and the main stem river into which they flow, drain the surrounding drainage basin of its surface water and groundwater , leading the water out into an ocean. The Irtysh is a chief tributary of the Ob river and is also the longest tributary river in

224-414: A left tributary which is called Right Fork Steer Creek. These naming conventions are reflective of the circumstances of a particular river's identification and charting: people living along the banks of a river, with a name known to them, may then float down the river in exploration, and each tributary joining it as they pass by appears as a new river, to be given its own name, perhaps one already known to

256-531: A notable rise-lip of land as 17th century maps often have the place name but likely derives from "rush leap" from the local width of the river. It then runs through Ickenham and on to Uxbridge , where it passes through the former grounds of RAF Uxbridge and Brunel University . The Pinn continues on to Pield Heath and Cowley , passing under the Grand Union canal before joining the Frays River , an anabranch of

288-442: A result, the rock types must be impervious and non-porous . A parallel drainage system occurs on elongate landforms like outcropping resistant rock bands), typically following natural faults or erosion (such as prevailing wind scars). The watercourses run swift and straight, with very few tributaries, and all flow in the same direction. This system forms on very long, uniform slopes, for instance, high rivers flowing southeast from

320-573: A single lower base level. An example of an integrated drainage is the area drained by the Rio Grande River . The sedimentary basins forming the modern Rio Grande Valley were not integrated into a single river system draining into the Gulf of Mexico until relatively recent geologic time. Instead, the basins formed by the opening of the Rio Grande rift were initially bolsons , with no external drainage and

352-822: A tangential or greater concentric path along a belt of weak rock so, with others, a roughly traced out ring can be seen. It is best displayed by streams draining a maturely dissected structural dome or basin where erosion has exposed rimming sedimentary strata of greatly varying degrees of hardness, as in the Red Valley , which nearly encircles the domal structure of the Black Hills of South Dakota . Astroblemes and mud diapirs are also thought to be able to cause this kind of drainage pattern. Angular drainage patterns form where bedrock joints and faults intersect at angles other than rectangular drainage patterns. Angles can be more or less than 90 degrees. An integrated drainage

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384-410: A third stream entering between two others is designated the middle fork; or the streams are distinguished by the relative height of one to the other, as one stream descending over a cataract into another becomes the upper fork, and the one it descends into, the lower ; or by relative volume: the smaller stream designated the little fork, the larger either retaining its name unmodified, or receives

416-481: A tree") are not straight and are the most common form of the drainage system. In this, there are many sub-tributaries (analogous to the twigs of a tree), which merge into tributaries of the main river (the branches and the trunk of the tree, respectively). They are seen to feed a river channel that matches and is strongly accordant to the overriding gradient of the land. Truly dendritic systems form in V-shaped valleys ; as

448-683: A trellis-like appearance of the system. They form where hard and soft formations exist on both banks of the main river, and are reflective of height, accentuated by erosion. Trellis drainage is characteristic of folded mountains, such as the Appalachian Mountains in North America and in the north part of Trinidad . Rectangular drainage develops on rocks that are of approximately uniform resistance to erosion , but which have two directions of jointing at approximately right angles or 90 degrees. The joints are usually less resistant to erosion than

480-429: Is a mature drainage system characteristic of arid climates. It is formed by coalescing of individual basins formerly separated by high ground, such as mountains or ridges. Headward erosion from a lower basin may breach the barrier, as may spilling over from a higher basin due to aggradation (accumulation of sediments in the basin). The effect of integration of a drainage system is to replace local higher base levels with

512-507: Is a tributary that joins the main stem river closer to its source than its mouth, that is, before the river's midpoint ; a late tributary joins the main stem further downstream, closer to its mouth than to its source, that is, after the midpoint. In the United States, where tributaries sometimes have the same name as the river into which they feed, they are called forks . These are typically designated by compass direction. For example,

544-491: Is the Canadian Shield . During the last ice age , the topsoil was scraped off, leaving mostly bare rock. The melting of the glaciers left land with many irregularities of elevation and a great deal of water to collect in the low points, resulting in the region's many lakes. The drainage basins are young and are still sorting themselves out; eventually the system will stabilize. In an annular drainage pattern, streams trace

576-513: The Aberdare Mountains in Kenya and many rivers of Myanmar . This sometimes indicates a major fault that cuts across an area of steeply folded bedrock. The geometry of a trellis drainage system is similar to that of a common garden trellis . Along a strike valley, smaller tributaries feed into the steep slopes of mountainsides. These tributaries enter the main river about perpendicular, causing

608-625: The American River in California receives flow from its North, Middle, and South forks. The Chicago River 's North Branch has the East, West, and Middle Fork; the South Branch has its South Fork, and used to have a West Fork as well (now filled in). Forks are sometimes designated as right or left. Here, the handedness is from the point of view of an observer facing upstream. For instance, Steer Creek has

640-450: The M40 motorway to the west) – about 0.62 miles (1 km) of this slopes down to the river. 51°30′51″N 0°28′47″W  /  51.5142°N 0.4797°W  / 51.5142; -0.4797 Dendritic drainage Per the lie of channels , drainage systems can fall into one of several categories, known as drainage patterns. These depend on the topography and geology of

672-634: The Colne, at Yiewsley . During the Second World War only, the Pinn was dammed near Pinner High Street for water for putting out fires from air raids. The middle and lower thirds of the course are between the Colne and Crane, all flowing south, thus making up parallel drainage . This is a 12-mile (19 km) walk through woodland, meadows and parks. It finishes at the Grand Union Canal towpath parallel to

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704-786: The Fray's River anabranch of the Colne. A short walk east along the Slough Arm of the Grand Union Canal connects. The Grand Union Canal towpath connects, linking in Brentford (east south-east), Watford and the Midlands (north), and the Paddington Arm (central London, east). All local sewerage runs to the distant Mogden Sewage Treatment Works discharging its treated waters to the Tideway . This spares

736-445: The Pinn from the incident nitrogen, bleach (ammonia) and other chemical biohazards which many of its catchment homes and business use and/or discharge. The Pinn's flow is weak save for after moderate or heavy rain. Worn tyre and motor oil run-off is from some roadside drains at biohazardous levels, particularly below the A40 road which is a trunk route of six lanes at this point (this becomes

768-535: The San Luis basin until a spillover event 440,000 years ago that drained Lake Alamosa and fully reintegrated the San Luis basin into the Rio Grande basin. Integrated drainages were widespread in western North America in the Paleocene and Eocene , and there is evidence of integrated drainages on the surface of Mars . Tributaries A tributary , or an affluent , is a stream or river that flows into

800-501: The bulk rock so erosion tends to preferentially open the joints and streams eventually develop along the joints. The result is a stream system in which streams consist mainly of straight line segments with right-angle bends and tributaries join larger streams at right angles. This pattern can be found with the Arun River in Nepal. In a radial drainage system, the streams radiate outwards from

832-416: The designation big . Tributaries are sometimes listed starting with those nearest to the source of the river and ending with those nearest to the mouth of the river . The Strahler stream order examines the arrangement of tributaries in a hierarchy of first, second, third and higher orders, with the first-order tributary being typically the least in size. For example, a second-order tributary would be

864-615: The eastern San Juan Mountains had joined the ancestral Rio Chama. The ancestral Rio Grande progressively integrated basins to the south, reaching the Palomas basin by 4.5 million years ago, the Mesilla basin by 3.1 million years, to Texas by 2.06 million years, and finally joining the Pecos River at 800,000 years to drain into the Gulf of Mexico. Volcanism in the Taos Plateau reduced drainage from

896-481: The land. All forms of transitions can occur between parallel, dendritic, and trellis patterns. A drainage system is described as accordant if its pattern correlates to the structure and relief of the landscape over which it flows. A discordant system or pattern does not correlate to the topography and geology of the area. Discordant drainage patterns are classified into two main types: antecedent and superimposed , while ante position drainage patterns combine

928-403: The main stream. Distributaries are most often found in river deltas . Right tributary , or right-bank tributary , and left tributary , or left-bank tributary , describe the orientation of the tributary relative to the flow of the main stem river. These terms are defined from the perspective of looking downstream, that is, facing the direction the water current of the main stem is going. In

960-464: The people who live upon its banks. Conversely, explorers approaching a new land from the sea encounter its rivers at their mouths, where they name them on their charts, then, following a river upstream, encounter each tributary as a forking of the stream to the right and to the left, which then appear on their charts as such; or the streams are seen to diverge by the cardinal direction (north, south, east, or west) in which they proceed upstream, sometimes

992-528: The two. In antecedent drainage, a river's vertical incision ability matches that of land uplift due to tectonic forces. Superimposed drainage develops differently: initially, a drainage system develops on a surface composed of 'younger' rocks, but due to denudation activities this surface of younger rocks is removed and the river continues to flow over a seemingly new surface, but one in fact made up of rocks of old geological formation. Dendritic drainage systems (from Greek δενδρίτης , dendrites , "of or like

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1024-433: The world with a length of 4,248 km (2,640 mi). The Madeira River is the largest tributary river by volume in the world with an average discharge of 31,200 m /s (1.1 million cu ft/s). A confluence , where two or more bodies of water meet, usually refers to the joining of tributaries. The opposite to a tributary is a distributary , a river or stream that branches off from and flows away from

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