Aiviekste is a river in
Latvia
Latvia ( or ; lv, Latvija ; ltg, Latveja; liv, Leţmō), officially the Republic of Latvia ( lv, Latvijas Republika, links=no, ltg, Latvejas Republika, links=no, liv, Leţmō Vabāmō, links=no), is a country in the Baltic region of ...
.
[Latvian Soviet Encyclopedia, p. 1-99.] It begins at
Lake Lubāns (the largest lake in Latvia) and drains into the
Daugava
The Daugava ( ltg, Daugova; german: Düna) or Western Dvina (russian: Западная Двина, translit=Západnaya Dviná; be, Заходняя Дзвіна; et, Väina; fi, Väinäjoki) is a large river rising in the Valdai Hills of Russ ...
(the largest river in Latvia). Aiviekste is the largest tributary of Daugava in Latvia. Aiviekste, along with the
Pededze, forms the unofficial border between two historical Latvian regions
Vidzeme
Vidzeme (; Old Latvian orthography: ''Widda-semme'', liv, Vidūmō) 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 n ...
and
Latgale
Latgale ( ltg, Latgola; ; ger, Lettgallen; be, Латгалія, Łathalija; pl, Łatgalia; la, Lettgallia), also known as Latgalia is one of the Historical Latvian Lands. It is the easternmost region and is north of the Daugava River. While ...
, although the administrative border was slightly different. The river is 114 kilometers long, with annual drainage 1.81 km³. Aiviekste is about 10-12 thousand 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 gre ...
and nearly after the ice age. Nearly a quarter of the river's flow is unregulated, but most of the river has been excavated, including with explosions.
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
Pededze, 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 (estuary). Near Krievciems - a dolomite quarry.
The river collects water mainly from the East Latvian lowland ( lv, Austrumlatvijas zemiene). 25% of the area of the Aiviekste basin is covered by forests, 15% - by marshes. There are many wet meadows 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, Pededze, 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
File:Stamps of Latvia, 2007-20.jpg, Railway bridge in Pļaviņas
References
{{Authority control
Rivers of Latvia