Rivers

Rivers are terrestrial flowing surface waters that drain well defined watersheds. A river typically has a geographic origin, termed its headwaters. In general, there are smaller rivers or streams that merge into the principal river of a given watershed; such influent streams are called tributaries of the principal river. Most rivers either discharge to a larger watercourse or flow into one of the seas of the world. In the less common circumstance, a river may terminate in an inland lake, with no outlet; this circumstance is called an endorheic basin. Rivers are home to a diversity of flora and fauna.

  • Columbia River Featured Article Columbia River Columbia River

    The Columbia River is the largest North American watercourse by volume that discharges to the Pacific Ocean. With headwaters at Columbia Lake, in Canadian British Columbia, the... More »

  • Ganges River dolphin Featured Article Ganges River dolphin Ganges River dolphin

    The Ganges River dolphin (scientific name: Platanista gangetica) is s freshwater cetacean closely related to the Indus river dolphin (Platanista minor). These two endangered... More »

  • U.S. Wild and Scenic Rivers Act Featured Article U.S. Wild and Scenic Rivers Act U.S. Wild and Scenic Rivers Act

    The U.S. Wild and Scenic Rivers Act of 1968 attempted to provide federal protection to certain pristine rivers of the USA. Major issues posed by the Act involve potential... More »

  • Daugava River Featured Article Daugava River Daugava River

    The Daugava River drains portions of the countries of Latvia, Belarus, Estonia and Russia, prior to discharging to the Gulf of Riga. Also known as the West Dvina River, this... More »

  • Zambezi River Featured Article Zambezi River Zambezi River

    The Zambezi River, Africa's fourth largest after the Nile, Zaire and Niger rivers, exhibits a length of 2700 kilometers prior to discharge to the Indian Ocean in... More »

  • Yangtze River Featured Article Yangtze River Yangtze River

    The Yangtze River, Asia's longest watercourse at about 6300 kilometers, has a basin that holds approximately one third of the population of China. The headwaters of the... More »

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Ecoregions of Oklahoma (EPA) Last Updated on 2014-06-28 15:53:00 (ftp://ftp.epa.gov/wed/ecoregions/ok/ok_front.pdf) Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance (Bryce, Omernik, and Larsen, 1999). Ecoregions are general purpose regions that are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources in the same geographical areas (Omernik and others, 2000). A Roman numeral hierarchical scheme... More »
Nile Delta flooded savanna Last Updated on 2014-05-16 14:56:41 WWF Terrestrial Ecoregions Collection Located on the northeastern corner of Africa, Egypt is part of the Palearctic realm linked to the north by the Middle East and the Mediterranean Sea, but also connected to sub-Saharan Africa by the Nile River. The Nile Delta is a vital stopover place for millions of birds making their annual migration between the Palearctic and Afrotropical realms, despite the fact that agriculture and dams have inextricably altered the floodplain delta ecosystem since 1960. The Nile Delta Flooded Savanna ecoregion extends along the River Nile from the Aswan High Dam, 1,100 kilometers (km) downstream to the mouth of the Nile as it enters the Mediterranean Sea. The delta is about 175 km long and 260 km wide. Since the construction of the Aswan High Dam, the riverine floodplains and delta are no longer subject to annual... More »
Nenjiang River grassland Last Updated on 2014-05-16 14:56:08 WWF Terrestrial Ecoregions Collection Nenjiang River grassland is an expansive low lying grassland drained by the Nenjiang and Songhua Rivers of China. The Nenjiang River originates among low hills that define China’s northeastern border with the Russian Far East. After winding through a series of valleys, the Nenjiang River flows down onto the Songhua-Nenjiang plain where flooded grasslands have historically provided important summer breeding habitat for a variety of migratory birds including six of the world’s fifteen crane species. The Red-crowned Crane, White-naped Crane, Siberian Crane and Demoiselle crane breed in this ecoregion, while the Common Crane and Hooded Crane stage here prior to migrating to their breeding habitat.  Overfishing and agricultural development threaten the bird populations of this species-rich... More »
Indus River Delta-Arabian Sea mangroves Last Updated on 2014-05-08 16:20:51 WWF Terrestrial Ecoregions Collection The Indus River Delta-Arabian Sea mangroves ecoregion represents a mangrove habitat that is adapted to some of the most extreme temperatures and salinity conditions in the Indo-Pacific region. As a transition from the marine to freshwater and terrestrial systems, mangroves provide critical habitat for numerous species of fishes and crustaceans that are adapted to live among the tangled mass of pneumatophores, the roots that reach up from the muddy, anaerobic substrate to obrain the supply of oxygen for the mangrove trees. This ecoregion lies at the delta of the Indus River, which originates in the Tibetan Plateau and flows through the northwestern part of India and into the arid Thar Desert in Pakistan before finally emptying into the Arabian Sea. There are high salinity levels in the sloughs because of the... More »
Zambezian flooded grasslands Last Updated on 2014-05-06 14:55:01 WWF Terrestrial Ecoregions Collection Located within the miombo and mopane woodlands of the Central African Plateau, Zambezian flooded grasslands are an anomaly of productivity and abundance in a landscape characterized by nutrient poor soil and vegetation. Unlike the surrounding woodlands that generally support animals only in rather low densities, the wetlands and floodplains of this ecoregion provide habitats to sizeable faunal populations, since food and water are abundant throughout most of the year. Large populations of waterbirds gather during the rainy season and numerous herd animals and  carnivores  still frequent the landscape. However, in a climate of rapid population growth and increasing need for land and natural resources, this delicate ecoregion may face increasing threat. Several conservation measures are urgently required... More »