The Pregolya or Pregola (; ; ; ) is a
river
A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...
in the
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
n
Kaliningrad Oblast
Kaliningrad Oblast () is the westernmost federal subjects of Russia, federal subject of the Russian Federation. It is a Enclave and exclave, semi-exclave on the Baltic Sea within the Baltic region of Prussia (region), Prussia, surrounded by Pola ...
exclave.
Name
A possible ancient name by
Ptolemy
Claudius Ptolemy (; , ; ; – 160s/170s AD) was a Greco-Roman mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine science, Byzant ...
of the Pregolya River is Chronos (from Germanic *''hrauna'', "stony"), although other theories identify Chronos as a much larger river, the
Nemunas.
The oldest recorded names of the river are ''Prigora'' (1302), ''Pregor'' (1359), ''Pregoll, Pregel'' (1331), ''Pregill'' (1460). Georg Gerullis connected the name with Lithuanian ''prãgaras'', ''pragorė̃'' ("abyss") and the Lithuanian verb ''gérti'' ("drink"). Vytautas Mažiulis instead derived it from ''spragė́ti'' or ''sprógti'' ("burst") and the suffix -''ara'' ("river").
Overview
It starts as a
confluence
In geography, a confluence (also ''conflux'') occurs where two or more watercourses join to form a single channel (geography), channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main ...
of the
Instruch and the
Angrapa
The Angrapa (, , , ) is a river that begins in northeastern Poland and ends in the Kaliningrad Oblast of Russia. Originating in Lake Mamry, it joins the 101-km-long Instruch at a point near Chernyakhovsk – variously assessed as lying 140, 1 ...
and drains into the
Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...
through the
Vistula Lagoon
The Vistula Lagoon is a brackish water lagoon on the Baltic Sea roughly 56 miles (90 km) long, 6 to 15 miles (10 to 19 km) wide, and up to 17 feet (5 m) deep, separated from the Gdańsk Bay by the Vistula Spit.
Geography
The lag ...
. Its length under the name of Pregolya is 123 km, 292 km including the
Angrapa
The Angrapa (, , , ) is a river that begins in northeastern Poland and ends in the Kaliningrad Oblast of Russia. Originating in Lake Mamry, it joins the 101-km-long Instruch at a point near Chernyakhovsk – variously assessed as lying 140, 1 ...
. The
basin has an area of 15,500 km
2. The average flow is 90 m
3/s.
Euler's
Seven Bridges of Königsberg
The Seven Bridges of Königsberg is a historically notable problem in mathematics. Its negative resolution by Leonhard Euler, in 1736, laid the foundations of graph theory and prefigured the idea of topology.
The city of Königsberg in Prussia ...
problem was based on the bridges crossing the river in
Königsberg
Königsberg (; ; ; ; ; ; , ) is the historic Germany, German and Prussian name of the city now called Kaliningrad, Russia. The city was founded in 1255 on the site of the small Old Prussians, Old Prussian settlement ''Twangste'' by the Teuton ...
(now
Kaliningrad
Kaliningrad,. known as Königsberg; ; . until 1946, is the largest city and administrative centre of Kaliningrad Oblast, an Enclave and exclave, exclave of Russia between Lithuania and Poland ( west of the bulk of Russia), located on the Prego ...
).
Cities and towns
*
Chernyakhovsk
Chernyakhovsk (; German: Insterburg) is a town in Kaliningrad Oblast, Russia, and the administrative center of Chernyakhovsky District. Located at the confluence of the Instruch and Angrapa rivers, which unite to become the Pregolya river bel ...
*
Znamensk
*
Gvardeysk
*
Kaliningrad
Kaliningrad,. known as Königsberg; ; . until 1946, is the largest city and administrative centre of Kaliningrad Oblast, an Enclave and exclave, exclave of Russia between Lithuania and Poland ( west of the bulk of Russia), located on the Prego ...
Tributaries
*
Pissa
*
Lava/Łyna
*
Angrapa
The Angrapa (, , , ) is a river that begins in northeastern Poland and ends in the Kaliningrad Oblast of Russia. Originating in Lake Mamry, it joins the 101-km-long Instruch at a point near Chernyakhovsk – variously assessed as lying 140, 1 ...
*
Instruch
See also
*
List of rivers of Russia
Russia can be divided into a European and an Asian part. The dividing line is generally considered to be the Ural Mountains. The European part is drained into the Arctic Ocean, Baltic Sea, Black Sea, and Caspian Sea. The Asian part is drained i ...
*
Bridges of Konigsberg problem
References
Rivers of Kaliningrad Oblast
{{Russia-river-stub