18-553: The River Ock is a small English river which is a tributary of the River Thames . It has as its catchment area the Vale of White Horse , a low-lying and wide valley in south Oxfordshire , and flows into the River Thames, at Abingdon on the reach above Culham Lock . The River Ock rises near the village of Little Coxwell . It collects tributaries from each village along the base of
36-400: A new river, to be given its own name, perhaps one already known to 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
54-400: A river or stream that branches off from and flows away from 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
72-425: A stream or river there the current is influenced by gravity, the term upstream (or upriver ) refers to the direction towards the source of the stream (or river ), i.e. against the direction of flow. Likewise, the term downstream or downriver describes the direction towards the mouth of the stream or river, in which the current flows. The term " left bank " and " right bank " refers to banks as seen from
90-446: Is a stream or river that flows into 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
108-411: Is also the longest tributary river in 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 ,
126-412: Is the flow of water in any one particular direction. The current varies spatially as well as temporally , dependent upon the flow volume of water, stream gradient , and channel geometry. In tidal zones , the current and streams may reverse on the flood tide before resuming on the ebb tide . On a global scale, wind and the rotation of the earth greatly influence the flow of ocean currents . In
144-800: The White Horse Hills , where springs emanating from the chalk hills allowed settlements to flourish in former times. Among these tributaries is the Osse Stream , rising in Cumnor . From Little Coxwell, the Ock runs around Longcot and flows past Stanford in the Vale , where it is about 10 feet (3 m) wide. The name of Stanford comes from stony ford , possibly alluding to the Ock crossing at Stanford Mill. Thence it runs past Charney Bassett , Lyford , Garford and Marcham Mill, before losing its identity and its waters to
162-484: The 21st century. Although normally placid, the Ock can flood low-lying areas of south Abingdon after persistent heavy rainfall; this recently occurred in April 2023, January 2024 and September 2024. The hydronym Ock appears to be derived from a Celtic word for 'salmon'. 51°40′N 1°17′W / 51.667°N 1.283°W / 51.667; -1.283 Tributary A tributary , or an affluent ,
180-524: The River Ock flows are the Jurassic sedimentary series ( Greensands , Gault , Kimmeridge Clay and corallian limestone ), while some of its tributaries arise in chalk springs. Until recent times, native crayfish and many freshwater fish species inhabited the river. Increased housing in the Vale, with the resultant surface drainage, may have threatened these species but surveys have not yet been performed in
198-521: The Thames at Abingdon by the old Hygienic Laundry building. An iron bridge crosses at the junction which was built by the Wilts & Berks Canal Company. This gives the erroneous impression that the Ock is that canal, but in fact the original canal entrance a few yards downstream is now blocked up. This has been replaced under a restoration project by a newer entrance closer to Culham Lock . The soils through which
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#1732856207155216-421: The direction the water current of the main stem is going. In 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
234-412: The first-order tributary being typically the least in size. For example, a second-order tributary would be the result of two or more first-order tributaries combining to form the second-order tributary. Another method is to list tributaries from mouth to source, in the form of a tree structure , stored as a tree data structure . Current (stream) In hydrology , a current in a water body
252-451: The handedness is from the point of view of an observer facing upstream. For instance, Steer Creek has 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
270-462: The opposite bank before approaching the confluence. An early tributary 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
288-643: The river into which they feed, they are called forks . These are typically designated by compass direction. For example, 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,
306-418: The smaller stream designated the little fork, the larger either retaining its name unmodified, or receives 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
324-432: The streams are seen to diverge by the cardinal direction (north, south, east, or west) in which they proceed upstream, sometimes 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:
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