The Syvash or Sivash ( Russian and Ukrainian: ; , Cyrillic: Сываш, "dirt"), also known as the or (, ''Gniloye More''; , ''Hnyle More''; , Cyrillic: Чюрюк Денъиз), is a large area of shallow

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into '' coastal lagoons'' (or ''barrier lagoons' ...

s on the west coast of the

Sea of Azov The Sea of Azov ( Crimean Tatar: ''Azaq deñizi''; russian: Азовское море, Azovskoye more; uk, Азовське море, Azovs'ke more) is a sea in Eastern Europe connected to the Black Sea by the narrow (about ) Strait of Ker ...

. Separated from the sea by the narrow

Arabat Spit The Arabat Spit ( uk, Арабатська коса; russian: Арабатская коса) or Arabat Arrow is a barrier spit that separates the large, shallow and very salty Syvash lagoons from the Sea of Azov. The spit runs between the Hen ...

, the water of the Syvash covers an area of around and the entire area spreads over about . The

Henichesk Strait The Henichesk Strait (alternatively Genichesk Strait; russian: Генический пролив, uk, Генічеська протока) is a narrow strait which connects the Syvash (the shallow lagoon system separating the Crimea from the res ...

is its eastern connection to the Sea of Azov. The Syvash borders the northeastern coast of the main

Crimean Peninsula Crimea, crh, Къырым, Qırım, grc, Κιμμερία / Ταυρική, translit=Kimmería / Taurikḗ ( ) is a peninsula in Ukraine, on the northern coast of the Black Sea, that has been occupied by Russia since 2014. It has a pop ...

. Central and Eastern Syvash were registered as wetlands of

Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian invas ...

under the

Ramsar Convention The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on W ...

; however, after the 2014 Russian annexation of Crimea they became subject to a territorial dispute. Since the 2022 Russian invasion of Ukraine, the entire Syvash has been occupied by

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eigh ...

Overview

The Syvash nearly cuts the Crimean Peninsula off from the mainland, serving as a natural border for its autonomous republic. The long () and narrow ()

runs to its east, separating it from the

. The two bodies are connected in the north at the

beside the port of Henichesk. To its west, the

isthmus of Perekop The Isthmus of Perekop, literally Isthmus of the Trench ( uk, Перекопський перешийок; transliteration: ''Perekops'kyy pereshyyok''; russian: Перекопский перешеек; transliteration: ''Perekopskiy peresheek ...

separates it from the

Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, ...

and connects Crimea to the mainland. Sivash, Ukraine

The Syvash is extremely shallow. The deepest place is about , with most areas between deep. The bottom is covered with

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel wh ...

up to thick. Being very shallow, the waters in the Syvash heat up in the summer and produce a putrid smell. The wide area for evaporation also leaves the water extremely salty. The amount of various salts is estimated at 200 million

metric ton The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...

s. Several industrial plants harvest the mineral resources of Syvash. The Syvash area is a

wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...

of international importance. The shores are low, slightly sloping, swampy and salty. In summer, the water level of Syvash decreases significantly, revealing barren

solonets Solonetz ( uk, Солонець, rus, Солоне́ц, p=səlɐˈnʲɛts) is a Reference Soil Group of the World Reference Base for Soil Resources (WRB). They have, within the upper 100 cm of the soil profile, a so-called "natric horizon" ...

soils called "syvashes" by locals. The Syvash is sometimes divided into the Western Syvash and Eastern Syvash. These are connected to each other by the

Chongar Strait The Chongar Strait (russian: Чонгарский пролив; uk, Чонгарська протока) is a short, shallow, narrow strait separating the eastern and western portions of the Syvash, the shallow lagoon system separating the Crim ...

History

During the

Russian Civil War {{Infobox military conflict , conflict = Russian Civil War , partof = the Russian Revolution and the aftermath of World War I , image = , caption = Clockwise from top left: {{flatlist, *Soldiers ...

, the Syvash became famous for a surprise crossing by the

Red Army The Workers' and Peasants' Red Army (Russian language, Russian: Рабо́че-крестья́нская Кра́сная армия),) often shortened to the Red Army, was the army and air force of the Russian Soviet Federative Socialist R ...

during the

Perekop-Chongar Operation The siege of Perekop, also known as the Perekop-Çonğar Operation, was the final battle of the Southern Front in the Russian Civil War from 7 to 17 November 1920. The White movement's stronghold on the Crimean Peninsula was protected by the � ...

Flora

The Syvash may appear red in color due to the salt-tolerant micro-alga ''

Dunaliella salina ''Dunaliella salina'' is a type of halophile green unicellular micro-algae especially found in hypersaline environments, such as salt lakes and salt evaporation ponds. Known for its antioxidant activity because of its ability to create large ...

''. The eastern parts of the Syvash contain less salt and are home to reeds and other wetland vegetation. The large islands in the Central Syvash are mainly covered with

steppe In physical geography, a steppe () is an ecoregion characterized by grassland plains without trees apart from those near rivers and lakes. Steppe biomes may include: * the montane grasslands and shrublands biome * the temperate grasslan ...

s consisting of

feather grass Feathergrass is a common name for several plants and may refer to: *'' Nassella'', a genus of bunchgrasses *'' Stipa'', a genus of perennial hermaphroditic grasses {{Short pages monitor