710 articles
Rupert
Rupert (Rivière Rupert), a major river in western Quebec flowing from Lac Mistassini to Rupert Bay, James Bay; named for Prince Rupert, first HBC governor; partially diverted since 2009 for Hydro-Québec's Eastmain-1-A and Rupert hydroelectric project.
Ruvuma
Ruvuma (Rovuma, Rio Rovuma) is a perennial East African river forming the Tanzania–Mozambique border, about 800 km long, draining a 155,500 km² basin shared with Malawi into the Indian Ocean at Mnazi Bay; a tri-national basin commission agreement was signed in 2026.
S. Francisco
S. Francisco is a freshwater ecoregion in Brazil defined by the Freshwater Ecoregions of the World project, covering the entire drainage basin of the Rio São Francisco.
Sa Dec
Sa Dec (Sa Đéc), city in Dong Thap province, Mekong Delta, Vietnam; provincial-level city since 2013 (5,981 ha, 152,237 people); famous for its late-19th-century flower village and as the setting of Duras's The Lover.
Sabarmati River
Sabarmati River: west-flowing Indian river rising in the Aravalli hills, Rajasthan, 371 km to the Gulf of Khambhat; seasonal monsoon-fed, flows through Ahmedabad, site of the Sabarmati Riverfront project and heavy pollution.
Sabine River (Texas–Louisiana)
Sabine chiefly denotes the Sabine River (Río de Sabinas), a 555-mile Texas–Louisiana border river draining 9,756 square miles into Sabine Lake and the Gulf, Texas's largest-discharge river.
Sabis
Sabis names several ancient entities: Caesar's Gallic river of the 57 BCE Nervian battle (now identified with the Selle, not the Sambre), a Peutinger road station on Italy's Savio, a Carmanian river, and a South Arabian god in Pliny.
Sacramento River
Sacramento River: California's largest river, draining a 27,000-square-mile basin carrying about 30% of the state's surface water into the Delta; home to four Chinook salmon runs, including endangered winter-run, managed through Shasta Dam temperature control.
Salado
Salado (Spanish, "salty") names several rivers in Arizona, Argentina, Chile, Texas, New Mexico, and Spain, plus the Salado archaeological culture (A.D. 1250–1450) of Arizona's Tonto Basin, known for polychrome pottery spread over 130,000 km².
Salmon River (Idaho)
The Salmon River, Idaho's "River of No Return," is a 425-mile Snake River tributary through the second-deepest gorge on the continent, with 125 miles designated Wild and Scenic in 1980 and key habitat for threatened Snake River salmon and steelhead.
Salween (river, Myanmar)
Salween (Nu Jiang in China, Thanlwin in Myanmar), a 2,820 km transboundary river from the Tibetan Plateau through Yunnan, Shan, Karenni, and Karen States to the Andaman Sea; over 10 million people, 16 ethnic groups, undammed main channel.
Samoas
Samoas (FEOW ecoregion 823) is a freshwater ecoregion of the Oceanic Islands type covering the Samoan archipelago in both Samoa and American Samoa, delineated for its endemic fish fauna including Kuhlia salelea and Stiphodon hydroreibatus.
San Miguel River
San Miguel River, southwestern Colorado tributary of the Dolores River; about 80 miles long, headwaters near 13,000 feet in the San Juan Mountains, one of the last unregulated rivers in the Colorado River watershed.
Sankuru (landform)
Sankuru River (Lubilash, Lubilanji), a 1,210 km right-bank tributary of the Kasai River in DR Congo, rising near Kamina, flowing north then west, with 2,500 m³/s average flow and navigable routes to Lusambo.
Santa Ana River
The Santa Ana River (Rio Santa Ana) is a 96-mile river in Southern California, flowing from the San Bernardino Mountains to the Pacific Ocean near Huntington Beach.
Santee River
The Santee River is a 143-mile South Carolina river formed by the Congaree-Wateree confluence, draining one of the East Coast's largest basins, dammed in 1941 for the Santee Cooper project, and partially rediverted back from the Cooper River in 1985.
São Francisco
São Francisco (Rio São Francisco, Opará): 2,863 km Brazilian river, longest entirely within Brazil, rising in Serra da Canastra, Minas Gerais, flowing to Alagoas; basin 639,219 km², major dams, semiarid water source.
Sartang
Sartang (Yakut: Сартаҥ) is a 620 km river in Yakutia, Russia; with the Dulgalakh it forms the Yana, rising from Lake Siskyuele in the Verkhoyansk Range. Also a village in Ilam, Iran, and a language of Arunachal Pradesh.
Sassandra
Sassandra, a major river of western Côte d'Ivoire flowing 650 km (or 442 km per one study) to the Gulf of Guinea, with the Buyo (1980) and Soubré (2017) dams and the town of Sassandra at its mouth.
Sava
Sava: 945 km river in South Eastern Europe, largest Danube tributary by discharge (~1,700 m³/s at Belgrade), basin of 97,713 km² shared by Slovenia, Croatia, Bosnia and Herzegovina, Serbia, and Montenegro; governed by the 2004 FASRB and ISRBC.
Save
Save (Sabi) River: 715 km river rising south of Harare, Zimbabwe, flowing 315 km through Mozambique to the Indian Ocean; basin ~88,395-102,000 km², Lundi tributary, 2023 transboundary water agreement.
Schuylkill River
The Schuylkill River (Dutch "hidden river") is a 130-mile Pennsylvania tributary of the Delaware River, the coal-carrying Schuylkill Navigation's route, once heavily polluted, now a restored drinking-water and recreation river.
Scotia - Fundy
Scotia - Fundy (FEOW ecoregion 119) is a temperate coastal rivers freshwater ecoregion covering Nova Scotia including Cape Breton Island, draining to the Atlantic via the Bay of Fundy or Gulf of St. Lawrence, home to the endemic Atlantic whitefish.
Seine
The Seine is the river of northern France rising on the Langres plateau and flowing through Paris to the English Channel; its 75,000 km² basin, tributaries Yonne, Marne, and Oise, water-quality history, and the 2024–2025 swimmability cleanup distinguish it.
Selenga
Selenga (Селенга), transboundary river of Mongolia and Siberia, largest tributary of Lake Baikal; 1,024 km, 447,000 km² basin, ~30 km³/yr inflow, large Ramsar delta.
Selennyakh
Selennyakh (Селеннях; Yakut Силээннээх), a 796 km left tributary of the Indigirka in Yakutia, Russia, draining 30,800 km² from the Chersky Range through the Moma-Selennyakh Depression and Aby Lowland; mean discharge about 180-220 m³/s, freezes October to May.
Senegal River
The Senegal River (fleuve Sénégal) is a 1,790 km West African river rising in Guinea and flowing to the Atlantic at Saint-Louis; its basin is managed by the 1972 OMVS, whose Diama and Manantali dams supply irrigation, hydropower, and flood control.
Sepik
Sepik River (Kaiserin Augusta), longest river of Papua New Guinea at 1,126 km, flowing through a largely intact 78,000 km2 basin of 300+ languages; nominated for World Heritage in 2006, threatened by the proposed Frieda River copper-gold mine.
Severn
Severn names several rivers: the River Severn (Afon Hafren), Britain's longest at 354 km from Plynlimon to the Bristol Channel; a 982 km Ontario river to Hudson Bay; a tidal Maryland river; plus Severn Sound and Township of Severn, Ontario.
Severnaya Sosva
Severnaya Sosva (Северная Сосьва), Northern Sosva, an 866-km left tributary of the Ob in KHMAO-Yugra, Russia; Ural-fed whitefish river with endemic tugun, historic Mangazeya trade route, and regulated indigenous fishery.