2,436 articles
Upper Amu Darya
Upper Amu Darya: mountainous headwater reach of the Amu Darya (Oxus) in the Pamir and Hindu Kush, bordering Afghanistan and Tajikistan; generates over 90% of the river's flow, about 72.6 km³ annually.
Upper Brahmaputra
Upper Brahmaputra (Yarlung Zangbo, Tsang Po) is the Tibetan Plateau portion of the Brahmaputra basin, about 240,000 km2, defined by glacier- and snowmelt-driven hydrology, late-1990s water yield regime shifts, and FEOW ecoregion 711.
Upper Congo
Upper Congo, FEOW freshwater ecoregion 540, the Lualaba reach of the Congo River in the DRC from the Shaba Plateau to the Upper Congo Rapids, with endemic molluscs and a poorly surveyed endemic fish fauna.
Upper Congo Rapids
Upper Congo Rapids, freshwater ecoregion 539 (FEOW), a stretch of the Lualaba/Congo River between Ubundu and Kisangani, DR Congo, where the river drops 60 m over 100 km through rapids including Boyoma Falls, forming a fish dispersal barrier with a rapids-adapted fauna.
Upper Danube
Upper Danube: upper course of the Danube River from the Black Forest through Austria to the Drava confluence; also WWF freshwater ecoregion 417, 248,000 km², temperate upland rivers with endemic lake whitefish and heavily altered hydrology.
Upper Huang He
The Upper Huang He (upper Yellow River) is the headwater reach of China's Yellow River on the Tibetan Plateau, freshwater ecoregion 634 supplying over 35% of the basin's water.
Upper Huang He Corridor
Upper Huang He Corridor (FEOW ecoregion 634): a Palearctic montane-freshwater ecoregion in China covering the Yellow River from the Himalayan exit to about Guide, Qinghai, plus Gansu's endorheic basins, with 1 endemic fish species.
Upper Irtysh
Upper Irtysh (Black Irtysh, Ertix He): headwater reach of the Irtysh River from the Altai glaciers in Xinjiang through Lake Zaysan to Ust-Kamenogorsk; also FEOW freshwater ecoregion 603 with 43 fish species, two endemics, and a large Soviet dam cascade.
Upper Klamath Lake
Upper Klamath Lake: Oregon's largest lake (305 km2, shallow), headwaters of the Klamath River; hypereutrophic with Aphanizomenon flos-aquae blooms, endangered Lost River and shortnose suckers, Link River Dam regulation since 1917, and Klamath Tribes' adjudicated instream water claim.
Upper Lancang (Mekong)
Upper Lancang (Mekong), ecoregion 724, the Chinese upper Mekong basin (Lancang Jiang, turbulent river). Tibetan Plateau headwaters, 11-dam cascade impounding 45.6 km3, 86.5% sediment trapping, endemic Schizothoracinae and Glyptosterninae fishes.
Upper Mackenzie
Upper Mackenzie (FEOW ecoregion 104) is a Canadian freshwater ecoregion of temperate floodplain rivers and wetlands covering the upper Mackenzie watershed across Alberta, British Columbia, Saskatchewan, and the NWT, defined by the Peace, Slave, Athabasca, and Hay rivers and the Peace-Athabasca Delta.
Upper Mississippi
Upper Mississippi: river reach from Lake Itasca, Minnesota, to the Ohio River confluence at Cairo, Illinois; with the Illinois River it forms the 1,300-mile UMRS, a 1986-designated national ecosystem and 9-foot-channel navigation system.
Upper Missouri
The Upper Missouri refers to the upper portion of the Missouri River and its basin, spanning Montana, Wyoming, the Dakotas, and Nebraska down to the Missouri–Platte confluence near Omaha.
Upper Parana
Upper Parana, or Upper Paraná, is a freshwater ecoregion covering the Rio Paraná basin above the former Guaíra Falls, mostly in Brazil and known for 131 endemic fish species.
Upper Rio Grande - Bravo
Upper Rio Grande - Bravo, FEOW freshwater ecoregion 132 (Río Bravo del Norte), covers Rio Grande watersheds from Colorado headwaters to the Río Conchos mouth; temperate upland rivers, C-grade health, 52% unsustainable water use.
Upper Salween
Upper Salween: FEOW freshwater ecoregion 721, Palearctic, tropical and subtropical upland rivers, covering the Salween (Nu) basin in China north of the Nanding River confluence, with 8 endemic fish species.
Upper Saskatchewan
Upper Saskatchewan (FEOW ecoregion 107) is a temperate upland rivers ecoregion covering the Saskatchewan River headwaters from the Canadian Rockies across southern Alberta and western Saskatchewan, with 41 fish species and endangered conservation status.
Upper Snake
Upper Snake: the Snake River above Shoshone Falls, Idaho, and its drainage (FEOW ecoregion 122), spanning Idaho, Wyoming, Nevada, and Utah; defined by the falls as a fish barrier, endemic sculpins, Reclamation reservoirs, and 487 kaf salmon flow augmentation.
Upper Tigris & Euphrates
Upper Tigris & Euphrates (FEOW ecoregion 442), a Palearctic temperate floodplain freshwater ecoregion in Turkey, Iraq, Syria, and Iran covering the upper Tigris and Euphrates rivers, their tributaries, and Iranian drainages, with high fish endemism and severe upstream-dam water stress.
Upper Uruguay
Upper Uruguay, FEOW freshwater ecoregion 333 (Alto Uruguay), the Río Uruguay basin above Yucumã Falls in Brazil and Argentina; basalt upland rivers with 27 endemic fish species and heavy dam impoundment.
Upper Usumacinta
Upper Usumacinta, FEOW freshwater ecoregion 174, tropical and subtropical upland rivers in eastern Chiapas, southeastern Tabasco, and northwestern Guatemala; upper Usumacinta basin above the San Pedro confluence, home of the endemic Chiapas catfish.
Upper Yukon
Upper Yukon (FEOW ecoregion 102) is a Nearctic Polar freshwaters ecoregion covering the upper Yukon River watershed in Yukon, British Columbia, and Alaska, draining to the Bering Sea, with a depauperate fish fauna and no endemic species.
Upper Zambezi Floodplains
Upper Zambezi Floodplains, or Barotse Floodplain (Bulozi Plain), a Ramsar floodplain-wetland ecoregion on the upper Zambezi in Zambia and Angola, annually flooded, flow-regulating, home of the Lozi people.
Ural
Ural (Урал; Kazakh Zhayyq; formerly Yaik until 1775), third longest river in Europe at 2,428 km, rising in the southern Ural Mountains and flowing through Russia and Kazakhstan to the Caspian Sea; only free-flowing Caspian tributary, with the basin's last natural sturgeon spawning grounds.
Urban water
Urban water: the water cycle of cities, covering supply, distribution, wastewater, stormwater, and modified natural flows. Key facts: large cities move 504 billion liters/day, one in four remain water stressed, WSUD retains 30-100% of water.
Uša (river, Lithuania)
Uša (Ušà) is a 105-km Belarusian river, a left tributary of the Nemunas rising southwest of Nesvizh, with a 1,220 km² basin, 7.3 m³/s mean discharge, frozen December to March; distinct from the same-named Neris tributary.
Usa (river, Russia)
Usa (Уса), river in the Komi Republic, Russia; largest tributary of the Pechora, 565 km long, basin 93,600 km², mean discharge 1,310 m³/s, frozen November to May, navigable 325 km from Ust-Usa.
Usumacinta
The Usumacinta is a Mesoamerican river about 1,100 km long, formed in Guatemala and flowing north through Chiapas and Tabasco to the Gulf of Mexico.
Utikuma
Utikuma Lake is a large, shallow lake in the Peace River drainage basin of northwestern Alberta, Canada, covering 288 km² about 65 km northeast of High Prairie.
Utus
Utus is the ancient Latin name of the Vit River in northern Bulgaria, a Danube tributary in Roman Moesia that marked a position on the Danube frontier.