The Aiviekste is a river in

Latvia Latvia, officially the Republic of Latvia, is a country in the Baltic region of Northern Europe. It is one of the three Baltic states, along with Estonia to the north and Lithuania to the south. It borders Russia to the east and Belarus to t ...

.Latvian Soviet Encyclopedia, p. 1-99. It begins at Lake Lubāns (the largest lake in Latvia) and drains into the

Daugava The Daugava ( ), also known as the Western Dvina or the Väina River, is a large river rising in the Valdai Hills of Russia that flows through Belarus and Latvia into the Gulf of Riga of the Baltic Sea. The Daugava rises close to the source of ...

(the largest river in Latvia). The Aiviekste is the largest tributary of the Daugava in Latvia. The Aiviekste, along with the

Pededze The Pededze () is a river in Latvia and Estonia. It has a length of , of which 131 km flow through Latvia. It flows in a generally southern direction. It is a right tributary of the Aiviekste, and the source of the Pededze is Lake Kirikum ...

, forms the unofficial border between two historical Latvian regions

Vidzeme Vidzeme (; Old Latvian orthography: ''Widda-semme'', ) is one of the Historical Latvian Lands. The capital of Latvia, Riga, is situated in the southwestern part of the region. Literally meaning "the Middle Land", it is situated in north-centra ...

and

Latgale Latgale (; ; ; ; ; ; Belarusian Latin alphabet, Belarusian Latin: ''Łathalija''; ), also known as Latgalia or Latgallia, is one of the Historical Latvian Lands. It is the easternmost region of the country and lies north of the Daugava River. Wh ...

, although the administrative border was slightly different. The river is 114 kilometers long, with annual drainage 1.81 km³. The Aiviekste is between 10,000 and 12,000 years old, formed at the end of the last

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

. Nearly a quarter of the river's flow is unregulated, but most of the river has been excavated, including with explosions. The Aiviekste flows from the northern end of Lake Lubāns, where it does a wide semicircle and then turns southwest. At this stage is the smallest drop, in addition, here Aiviekste receives the largest tributaries

, Bolupe and Iča. Furthermore, it was straightened and deepened for 83 km. At the lower end, Aiviekste flows through a slightly undulating area. There are several islands, sandbars and about 15 stone sills here in the river. The small Aiviekste hydroelectric power plant (1.4 MW) was built on one of these island groups. After the construction of the Pļaviņu hydroelectric power plant, the lower end of Aiviekste is flooded with a reservoir. It flows through the towns of Lubāna and

Pļaviņas Pļaviņas (; ) is a town in Aizkraukle Municipality in Latvia. The town is located on the Daugava river. The population in 2020 was 2,974. Latvian law defines the town of Pļaviņas as belonging partly to the Vidzeme region and partly to Latgale ...

(estuary). Near Krievciems - a dolomite quarry. The river collects water mainly from the East Latvian lowland (). 25% of the area of the Aiviekste basin is covered by forests, 15% - by marshes. There are many

wet meadow A wet meadow is a type of wetland with soils that are Solubility, saturated for part or all of the growing season which prevents the growth of trees and brush. Debate exists whether a wet meadow is a type of marsh or a completely separate type of ...

s in the basin, large swamps. Aiviekste is rich in fish.Small Encyclopedia of Latvian SSR, p. 1-39. Aiviekste is regulated by locks and canals, as its flow capacity is several times too low when the flood season begins in Lake Lubāns. Until the end of 20th century, during the spring floods, the waters of Aiviekste flowed back into Lubāns upstream due to the influx of tributaries, which intensified the floods there. The Aiviekste floodplain in the middle of the river is a nature reserve as a habitat for birds and a home for rare plants. The fall of the river to the Aiviekste hydroelectric power station of Aiviekste is 1 m by 14 km, and only after that in the last 14 km it increases tenfold.Upesoga: boating in Aiviekste
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Tributaries

* Left side: Zvidze, Isliena, Abaine * Right side: Iča, Piestiņa,

, Liede, Kuja, Svētupe, Arona, Veseta

Gallery

File:Aiviekste pie Vesetas tilta 2003-06-28.jpg, Aiviekste near bridge of Veseta File:Aiviekstes HES aizsprosts - panoramio.jpg, Aiviekste power plant File:Aiviekste, 27.09.2015.jpg, Aiviekste in Ļaudona

References

{{Authority control Rivers of Latvia