2,436 articles
San Matías Gulf
San Matías Gulf (Golfo San Matías), Argentina's large semi-enclosed Patagonian gulf between Río Negro and Chubut, about 19,700 km², tide-dominated, high salinity, right whale habitat, and site of contested LNG and oil export projects.
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.
Sandhill crane
Sandhill crane (Antigone canadensis, Grus canadensis): abundant North American crane with six subspecies, three migratory and three non-migratory; Mid-Continent Population about 1.06 million, staging on the Platte River.
Sankarani-Fié
Sankarani-Fié is a Ramsar wetland site (no. 1167) in the Kankan region of Guinea, designated 17 January 2002, covering the Sankarani river basin; extended from 1,015,200 to 1,656,000 ha, noted for floodplains, fisheries, and hippopotami.
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.
Santa Cruz Basin
Santa Cruz Basin: deep (1,900 m) intermediate basin of the California Continental Borderland south of the Channel Islands; slumping, canyon-fed sedimentation, up to 4 km Miocene subsidence, gas hydrate BSR. Not the Arizona groundwater basin or central California Tertiary basin.
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.
Santo Antão
Santo Antão (Ilha de Santo Antão), Cape Verde's westernmost and northernmost island: 779 km², Tope da Coroa 1,979 m, about 44,000 people, three municipalities, reached only by ferry from Mindelo; a mountainous hiking and farming island, not the Brazilian city Vitória de Santo Antão.
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.
Sararken Ridges
Sararken Ridges (formerly Sararken Ridge) is an undersea ridge feature in Indonesian waters named for the Papuan word for octopus, adopted into the IHO-IOC GEBCO Gazetteer at SCUFN-38 in Bali, November 2025.
Sargasso Sea
The Sargasso Sea, within the North Atlantic Subtropical Gyre, is the only sea without a land boundary, bounded by the Gulf Stream, North Atlantic, Canary, and Equatorial Currents and covered in holopelagic Sargassum.
Saronic Gulf (Σαρωνικός κόλπος)
The Saronic Gulf is a semi-enclosed embayment of the Aegean Sea that serves as the marine gateway for Athens and Piraeus. It holds islands like Salamis and Aegina and is a major sailing area.
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.
Sarygamysh
Sarygamysh (Sarykamysh) Lake, a large brackish lake on the Turkmenistan-Uzbekistan border between the Caspian and Aral seas, formed since the 1960s from Amu Darya irrigation drainage water, over 3,000 km2, salinity about 11 g/l.
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.
Sasykkol
Sasykkol (Сасықкөл), a large shallow freshwater lake in the Balkhash-Alakol basin of southeastern Kazakhstan, fed by the Tentek River and drained to Alakol via Koshkarkol; 736 km², max depth 4.7 m, part of Ramsar site 1892.
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.
Savu Sea
The Savu Sea (also spelled Sawu Sea; Indonesian Laut Sawu) is an East Indian Archipelago sea in eastern Indonesia, enclosed by the islands of Flores, Sumba, and Timor.
Scapa Flow
Scapa Flow is a large enclosed natural harbor in the Orkney Islands of Scotland, used as the Royal Navy's main fleet base in both world wars.
Schollaert Channel
Schollaert Channel: Antarctic channel in the Palmer Archipelago between Anvers and Brabant Islands, connecting Dallmann Bay and Gerlache Strait; discovered 1898 by de Gerlache's Belgian expedition, named for statesman François Schollaert.
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.
Scoresby Sound
Scoresby Sound (Kangertittivaq, Scoresby Sund), East Greenland's vast fjord system: world's largest, ~350 km long, 13,700 km², named by William Scoresby Jr. in 1822, with Ittoqqortoormiit its only town.
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.
Se7en Wetlands
Se7en Wetlands is a 1,640-acre constructed treatment wetland in Lakeland, Florida, providing tertiary wastewater treatment since 1987 on former phosphate mine land, opened as a public park in 2018 with trails, wildlife, and an education center project.
Sea
A sea is a large saltwater body smaller than an ocean, usually at the land-ocean margin and partially enclosed by land; the Sargasso Sea, defined only by currents, is the exception. Covers tides, currents, waves, climate role, and human use.
Sea ice in the Pacific Ocean
Sea ice in the Pacific Ocean forms at its polar margins: the Bering Sea, the Sea of Okhotsk, and the Pacific edge of the Antarctic pack.
Sea of Azov
The Sea of Azov, historically Lake Maeotis, is a shallow brackish inland sea of Eastern Europe connected to the Black Sea by the Kerch Strait.
Sea of Crete
The Sea of Crete (Greek: Kritiko Pelagos, "Cretan Sea") is the southernmost part of the Aegean Sea, lying between Crete and the Cyclades, and the Aegean's deepest basin at 2,500 m.