Portal:Rivers

The Rivers Portal

Introduction

A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it runs out of water, or only flow during certain seasons. Rivers are regulated by the water cycle, the processes by which water moves around the Earth. Water first enters rivers through precipitation, whether from rainfall, the runoff of water down a slope, the melting of glaciers or snow, or seepage from aquifers beneath the surface of the Earth.

Rivers flow in channeled watercourses and merge in confluences to form drainage basins, areas where surface water eventually flows to a common outlet. Drainage divides keep rivers separated from other courses of water and causes upstream water within the confines of the divide to fall into the downhill stream. Rivers have a great effect on the landscape around them. They may regularly overflow their banks and flood the surrounding area, spreading nutrients to the surrounding area. Sediment or alluvium carried by rivers shapes the landscape around it, forming deltas and islands where the flow slows down. Rivers rarely run in a straight line, instead, they bend or meander; the locations of a river's banks can change frequently. Rivers get their alluvium from erosion, which carves rock into canyons and valleys.

Rivers have sustained human and animal life for millennia, including the first human civilizations. The organisms that live around or in a river such as fish, aquatic plants, and insects have different roles, including processing organic matter and predation. Rivers have produced abundant resources for humans, including food, transportation, drinking water, and recreation. Humans have engineered rivers to prevent flooding, irrigate crops, perform work with water wheels, and produce hydroelectricity from dams. People associate rivers with life and fertility and have strong religious, political, social, and mythological attachments to them. (Full article...)

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Scotch Run at Mifflin Cross Roads

Scotch Run is one of the main tributaries of Catawissa Creek in Columbia County, Pennsylvania, in the United States. It is approximately 7.8 miles (12.6 km) long and flows through Beaver Township and Main Township. The stream's watershed has an area of 9.10 square miles (23.6 km²). The stream is infertile and acidic. It is 7.2 feet (2.2 m) wide in its upper reaches and 17.0 feet (5.2 m) wide in its lower reaches. The main rock formations in the watershed include the Mauch Chunk Formation, the Pocono Formation, the Pottsville Formation, and the Spechty Kopf Formation. The main soils include Leck Kill soil and Hazleton soil. It flows between Nescopeck Mountain and McCauley Mountain.

Nearly all of Scotch Run's length is within 1,640 feet (500 m) of a road. However, most of its length is not within 328 feet (100 m) of one. Part of Pennsylvania State Game Lands Number 58 is in the watershed and ephemeral natural pool system is located near the stream. The area in the vicinity of the stream was settled relatively late compared to the surrounding areas. The Pennsylvania Fish and Boat Commission carried out a survey of the creek in 1977. Scotch Run is designated as a Coldwater Fishery and a Migratory Fishery. In 1997, three species of fish were observed in the upper reaches of the stream, while eight species were observed in the lower reaches. Both reaches contained brown trout and brook trout. There is a hemlock-mixed hardwood palustrine forest along the stream. (Full article...)

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I do not know much about gods; but I think that the river is a strong brown god—sullen, untamed and intractable.

— T. S. Eliot, "Four Quartets," in The Dry Salvages

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Photograph: Poco a poco

Gran Valira river spanned by the Pont de la Margineda in Andorra

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The following are images from various river-related articles on Wikipedia.

Image 1In Dante's Inferno, Charon ferries souls across the subterranean river Acheron. (from Subterranean river)
Image 2Co-occurrence network of a bacterial community in a stream (from River ecosystem)
Image 3A whitewater canoe with yellow air bags. (from Whitewater)
Image 4Flowing rivers can act as dispersal vectors for plant matter and invertebrates. (from River ecosystem)
Image 5Whitewater at Yosemite (from Whitewater)
Image 6Anthropogenic influences on river systems. Examples are mainly from settings with a modest technological influence, especially in the period of about 10,000 to 4000 cal yr BP. (from River ecosystem)
Image 7A weir on the River Calder, West Yorkshire (from River ecosystem)
Image 8Periphyton (from River ecosystem)
Image 9Castle Geyser, Yellowstone National Park (from River ecosystem)
Image 10Different biofilm components in streams. Principal components are algae and bacteria. (from River ecosystem)
Image 11The cave of source of the Buna can be entered by boat and dived through a cave system serving as an effluence of the Zalomka. (from Subterranean river)
Image 12This stream operating together with its environment can be thought of as forming a river ecosystem. (from River ecosystem)
Image 13Map of the world showing elevation levels (from Upland and lowland)
Image 14Leaf litter is an allochthonous energy source. (from River ecosystem)
Image 15Common water hyacinth in flower (from River ecosystem)
Image 16A pensive Cooplacurripa River, NSW (from River ecosystem)
Image 17The Effra is one of the subterranean rivers of London. It empties into the Thames by Vauxhall Bridge, from which this photograph was taken. (from Subterranean river)
Image 18Rapids in Mount Robson Provincial Park (from River ecosystem)
Image 19Example of a river food web. Bacteria can be seen in the red box at the bottom. Bacteria (and other decomposers, like worms) decompose and recycle nutrients back to the habitat, which is shown by the light blue arrows. Without bacteria, the rest of the food web would starve, because there would not be enough nutrients for the animals higher up in the food web. The dark orange arrows show how some animals consume others in the food web. For example, lobsters may be eaten by humans. The dark blue arrows represent one complete food chain, beginning with the consumption of algae by the water flea, Daphnia, which is consumed by a small fish, which is consumed by a larger fish, which is at the end consumed by the great blue heron. (from River ecosystem)
Image 20New Zealand longfin eels can weigh over 50 kilograms. (from River ecosystem)
Image 21The Puerto Princesa cave can be entered by boat. (from Subterranean river)
Image 22Pondweed is an autochthonous energy source. (from River ecosystem)
Image 23A forest stream in the winter near Erzhausen, Germany (from River ecosystem)
Image 24A subterranean river in the Cross Cave system of Slovenia. (Scale shown by people in photograph.) (from Subterranean river)
Image 25Rafting is a watersport where buoyancy aids, helmets and wetsuits are mandatory and often imposed by law, due to the constant risk of falling off the boat and into the rapids (from Whitewater)
Image 26Cascade in the Pyrénées (from River ecosystem)
Image 27The brook trout is native to small streams, creeks, lakes, and spring ponds. (from River ecosystem)
Image 28Devil's Throat Cave subterranean river from above (from Subterranean river)

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Did you know?

... that the Kettle Creek (pictured) watershed contains eight percent of the Class A Wild Trout Streams in Pennsylvania?
... that water from the Little Applegate River was used in the mine in Sterlingville, the largest hydraulic mine in Oregon and possibly the entire western United States?
... that there are at least 35 sources of acid mine drainage in the Mahanoy Creek watershed?

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Photograph: Avarim

River Ness at Inverness

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