710 articles
Lungwebungu
The Lungwebungu (Portuguese: Lungué-Bungo) is the longest tributary of the upper Zambezi, rising in central Angola and flowing 1,032 km southeast to join the Zambezi at Lukulu, Zambia.
Lúrio
Lúrio (Rio Lúrio, Lurio River), a roughly 500–593 km river in northern Mozambique draining Niassa, Cabo Delgado, Nampula, and Zambézia; its ~61,000 km² basin is the largest entirely within Mozambique, emptying into Baía do Lúrio.
Mackenzie River
The Mackenzie River drains Great Slave Lake to the Arctic Ocean through Canada's largest basin, about 1.8 million km2. Explored by Alexander Mackenzie in 1789 (Dene name Deh-Cho), it is the fourth-largest circumpolar river by discharge.
Macquarie
Macquarie River (Wambuul Macquarie), NSW inland river rising near Bathurst, flowing northwest to the Barwon; named for Governor Lachlan Macquarie; feeds Burrendong Dam and the Macquarie Marshes. Distinct from Port Macquarie and Tasmania's Macquarie River.
Madagascar Eastern Lowlands
Madagascar Eastern Lowlands, FEOW ecoregion 583, a narrow coastal strip of tropical and subtropical coastal rivers draining to the Indian Ocean, with 69 native fish species, Bedotia endemics, Astacoides crayfish, and brackish lagoons.
Madeira River
Madeira River, largest Amazon tributary (Mamoré + Beni at Villa Bella), ~1,200 km to the Amazon; whitewater, ~430 Mt/yr sediment, Santo Antônio and Jirau dams, record 2014 flood and 2024 drought.
Madre de Dios
Madre de Dios, also Rio Madre de Dios, is a roughly 965 km Andes-to-Amazon river in southeastern Peru and Bolivia, a Madeira tributary; its Peruvian department, capital Puerto Maldonado, was created in 1912 and faces gold-mining mercury contamination.
Mae Khlong
Mae Khlong (แม่น้ำแม่กลอง), a ~140 km river in western Thailand formed by the Khwae Yai and Khwae Noi, flowing through Kanchanaburi, Ratchaburi, and Samut Songkhram to the Gulf of Thailand; dammed by Srinagarind, Vajiralongkorn, and Mae Klong dams.
Magdalena - Sinu
Magdalena - Sinu, FEOW freshwater ecoregion 302, Colombia; combines the Magdalena, Cauca, and Sinu drainages flowing to the Caribbean Sea; ~233 fish species, 68% endemic, threatened by dams and deforestation.
Magdalena River
The Magdalena River (Río Magdalena), Colombia's principal river, runs about 1,540 km from the Páramo de las Papas to the Caribbean; its basin holds 80% of the population and it was the country's historic steamboat artery.
Mahakam
Mahakam (Sungai Mahakam), major river of East Kalimantan, Borneo, Indonesia, roughly 920–980 km long, draining 77,095 km² into the Makassar Strait; known for its fan-shaped mixed tide–fluvial delta, middle lakes, and the freshwater Pesut Irrawaddy dolphin.
Mahanadi (ମହାନଦୀ)
Mahäna Nadï (Mahanadi, ମହାନଦୀ, महानदी), 'great river' in Sanskrit, is a major east-flowing peninsular Indian river, 851 km long, rising in Chhattisgarh's Dhamtari district, flowing through Odisha, home of the Hirakud Dam, and draining to the Bay of Bengal.
Main (river)
The Main, or River Main, is a river in Germany and the longest right tributary of the Rhine, formed by the Red Main and White Main and flowing through Franconia.
Malay Peninsula Eastern Slope
Malay Peninsula Eastern Slope (FEOW ecoregion 734) is a freshwater ecoregion of eastern Peninsular Malaysia drainages from Prachuap Khiri Khan, Thailand to Singapore, a Sundaic fauna transition zone and identified freshwater fish conservation priority.
Malebo Pool
Malebo Pool (formerly Stanley Pool) is a 35-km-long, lake-like widening of the Congo River between the DRC and Republic of the Congo, with Kinshasa and Brazzaville on opposite shores, formed by a rock-sill barrier above the lower Congo rapids.
Mamoré
Mamoré River (Río Mamoré), Bolivian-Brazilian white-water river, about 1,930 km long, formed by the Chaparé and Ichilo rivers; joins the Beni to form the Madeira, a major Amazon tributary.
Mamore - Madre de Dios Piedmont
Mamore - Madre de Dios Piedmont, FEOW freshwater ecoregion 318, upper Madeira headwaters in Bolivia, Peru, and Brazil; whitewater Beni, Mamoré, and Madre de Dios rivers, about 80 endemic fish, and mercury contamination from gold mining.
Maquan
Maquan (Maquan Tsangpo, Maquan River, Tachog Khabab), the ~270 km Tibetan headwater branch of the Yarlung Tsangpo (upper Brahmaputra) in Burang and Saga counties, rising from Himalayan glaciers at over 5,200 m.
Marañón River
The Marañón River (Río Marañón) is a ~1,400 km Peruvian river whose confluence with the Ucayali forms the Amazon; it supplies about 10% of the Amazon's discharge, was long considered its source, and faces major dam proposals.
Maritsa (Марица)
Maritsa (Марица; Evros, Meriç; ancient Hebros), 537 km Balkan river rising in the Rila Mountains, flowing through Bulgaria, Greece, and Turkey to the Aegean, a flood-prone transboundary border river.
Markha
Markha (Марха) is a 1,181-km river in Yakutia, Russia, a left tributary of the Vilyuy in the Lena basin, rising on the Vilyuy Plateau. Its basin holds Yakutia's diamond fields and the Kraton-3 (1978) nuclear explosion site; not the Ladakh Markha River.
Marne (river)
The Marne is a 525 km river in northern France rising on the Langres plateau and the Seine's main tributary, which it joins at Charenton-le-Pont upstream of Paris.
Maya (landform)
Maya (landform): chiefly the Maya River (Мая, маайа), a right tributary of the Aldan in Siberia, over 1,050 km long; also the Maya Mountains of Belize, Sudan's Mayas wetlands, and a Leyte stream.
Mayran - Viesca
Mayran - Viesca, FEOW ecoregion 163, is a closed-basin xeric freshwater ecoregion of north-central Mexico centered on the Nazas-Aguanaval drainage, known for endemic desert pupfishes, minnows, and suckers and two extinct Parras basin species.
Mbomou
Mbomou (Bomu) River, Central African river rising on the Sudan–CAR frontier, flowing west along the DRC border; joins the Uele to form the Ubangi, a major Congo tributary.
Meander
A meander is a bend in a river that grows more pronounced as water erodes the outside of the curve and deposits sediment on the inside.
Meander neck
Meander neck: the narrow land strip between the two limbs of a river meander bend. When migration narrows it below one channel width, a neck cutoff breaches it, forming an oxbow lake; distinct from chute cutoffs.
Mearim
Mearim (Rio Mearim): river in Maranhão, Brazil, rising on the Serra da Menina and flowing to São Marcos Bay; largest basin in the state, with a 646-km navigable waterway and tributaries Pindaré and Grajaú.
Mekong (湄公河)
The Mekong (湄公河), called Lancang in China, is a roughly 4,900 km river flowing through six countries to the Mekong Delta, supporting the world's largest inland fishery and a basin reshaped by dams, sediment loss and mining pollution.
Meta
Meta (Río Meta), major Colombian river and largest Colombian tributary of the Orinoco, about 804-1,250 km long, rising in the Andes, crossing the Llanos Orientales, navigable, joining the Orinoco near Puerto Carreño.