Portal:Rivers

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The Rivers Portal

Introduction

Elwha River in the Olympic Peninsula

A river is a natural flowing watercourse, usually a freshwater stream, flowing on the Earth's land surface or inside caves towards another waterbody at a lower elevation, such as an ocean, sea, bay, lake, wetland, or another river. In some cases, a river flows into the ground or becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to by names such as creek, brook, and rivulet. There are no official definitions for these various generic terms for a watercourse as applied to geographic features, although in some countries or communities, a stream is customarily referred to by one of these names as determined 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; in English the language is vague compared to some langauges like French, where a fleuve flows into the sea and a rivière is a tributary of another rivière or fleuve.

Rivers are an important part of the water cycle. Water from a drainage basin generally collects into a river through surface runoff from precipitation, meltwater released from natural ice and snowpacks, and other underground sources such as groundwater recharge and springs. Rivers are often considered major features within a landscape; however, they actually only cover around 0.1% of the land on Earth. Rivers are also an important natural terraformer, as the erosive action of running water carves out rills, gullies, and valleys in the surface as well as transferring silt and dissolved minerals downstream, forming river deltas and islands where the flow slows down. As a waterbody, rivers also serve crucial ecological functions by providing and feeding freshwater habitats for aquatic and semiaquatic fauna and flora, especially for migratory fish species, as well as enabling terrestrial ecosystems to thrive in the riparian zones.

Rivers are significant to humankind since many human settlements and civilizations are built around sizeable rivers and streams. Most of the major cities of the world are situated on the banks of rivers, as they are (or were) depended upon as a vital source of drinking water, for food supply via fishing and agricultural irrigation, for shipping, as natural borders and/or defensive terrains, as a source of hydropower to drive machinery or generate electricity, for bathing, and as a means of disposing of waste. In the pre-industrial era, larger rivers were a major obstacle to the movement of people, goods, and armies across regions. Towns often developed at the few locations suitable for fording, building bridges, or supporting ports; many major cities, such as London, are located at the narrowest and most reliable sites at which a river could be crossed via bridges or ferries. (Full article...)

White Deer Hole Creek near the Fourth Gap of South White Deer Ridge

White Deer Hole Creek is a 20.5-mile (33.0 km) tributary of the West Branch Susquehanna River in Clinton, Lycoming and Union counties in the U.S. state of Pennsylvania. A part of the Chesapeake Bay drainage basin, the White Deer Hole Creek watershed drains parts of ten townships. The creek flows east in a valley of the Ridge-and-valley Appalachians, through sandstone, limestone, and shale from the Ordovician, Silurian, and Devonian periods.

As of 2006, the creek and its 67.2-square-mile (174 km2) watershed are relatively undeveloped, with 28.4 percent of the watershed given to agriculture and 71.6 percent covered by forest, including part of Tiadaghton State Forest. The western part of White Deer Hole Creek has very high water quality and is the only major creek section in Lycoming County classified as Class A Wild Trout Waters, defined by the Pennsylvania Fish and Boat Commission as "streams which support a population of naturally produced trout of sufficient size and abundance to support a long-term and rewarding sport fishery." The rest of the creek and its major tributary (Spring Creek) are kept stocked. There are opportunities in the watershed for canoeing, hunting, and camping, and trails for hiking and horseback riding. (Full article...)
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Rivers know this: There is no hurry, we shall get there some day.

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Photograph: Villy Fink Isaksen

The Skjálfandafljót at Route 1 in northern Iceland. In the background is the waterfall of Goðafoss

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Maksimovsky rock in the Chusovaya River in Russia

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Tagus River
Tagus River
Photograph: David Iliff
The Tagus River, seen here passing through the World Heritage listed city of Toledo, Spain. It is the longest river on the Iberian Peninsula at 1,038 kilometres (645 mi). It begins its journey in the Albarracín mountains in Spain, and follows a very constricted course for much of its length before reaching the Atlantic Ocean in Portugal.

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