The Venta (Latvian pronunciation , Lithuanian , , ,
Livonian ''Vǟnta joug'') 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 north-western
Lithuania
Lithuania, officially the Republic of Lithuania, is a country in the Baltic region of Europe. It is one of three Baltic states and lies on the eastern shore of the Baltic Sea, bordered by Latvia to the north, Belarus to the east and south, P ...
and western
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 ...
. Its source is near
Kuršėnai
Kuršėnai (; Samogitian dialect, Samogitian: ''Koršienā'') is a city in northwestern Lithuania, Šiauliai County, Šiauliai district municipality. It is the twenty-fifth largest city in Lithuania. According to the 2023 estimate, it had 10,651 r ...
in the Lithuanian
Šiauliai County
Šiauliai County () is one of ten counties in Lithuania. It is in the north of the country, and its capital is Šiauliai. On 1 July 2010, the county administration was abolished, and since that date, Šiauliai County remains as a territorial a ...
. It flows 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 ...
at
Ventspils
Ventspils () is a state city in northwestern Latvia in the historical Courland region of Latvia, and is the sixth largest city in the country.
At the beginning of 2020, Ventspils had a population of 33,906. It is situated on the Venta River and ...
in Latvia.
On the territory of Lithuania along the Venta are cities
Užventis,
Kuršėnai
Kuršėnai (; Samogitian dialect, Samogitian: ''Koršienā'') is a city in northwestern Lithuania, Šiauliai County, Šiauliai district municipality. It is the twenty-fifth largest city in Lithuania. According to the 2023 estimate, it had 10,651 r ...
,
Venta,
Viekšniai
Viekšniai ( Samogitian language, Samogitian: ''Vėikšnē'', ''Vekshne'', ) is a list of cities in Lithuania, town in the Mažeikiai district municipality, Lithuania. It is located south-east of Mažeikiai. The etymology of the town's name pro ...
and
Mažeikiai
Mažeikiai (; Samogitian: ''Mažeikē''; ; ) is a city in northwestern Lithuania, on the Venta River. It has a population of around 32,000, making it the eighth largest city in Lithuania and eighteenth largest city in the Baltic States. Th ...
. In Latvia, the cities of
Skrunda,
Kuldīga
Kuldīga () () is a town in the Courland region of Latvia, in the western part of the country. It is the center of Kuldīga Municipality with a population of approximately 13,500.
Kuldīga was first mentioned in 1242. It joined the Hanseatic L ...
,
Piltene and
Ventspils
Ventspils () is a state city in northwestern Latvia in the historical Courland region of Latvia, and is the sixth largest city in the country.
At the beginning of 2020, Ventspils had a population of 33,906. It is situated on the Venta River and ...
are located on the Venta river.
Venta Rapid, the widest waterfall in Europe, is on Venta river in
Kuldīga
Kuldīga () () is a town in the Courland region of Latvia, in the western part of the country. It is the center of Kuldīga Municipality with a population of approximately 13,500.
Kuldīga was first mentioned in 1242. It joined the Hanseatic L ...
, Latvia.
Basin system
The river has only one tributary longer than 100 km, the
Abava. Other major tributaries include the
Virvyčia (99.7 km) and the
Varduva (96 km), which flows into the Venta at the
Latvia–Lithuania border.
Smaller tributaries include the
Avižlys,
which runs for 20 kilometers and flows into the Venta River and the 30 kilometre
Uogys which joins the Venta less than 1 km upstream of the Avižlys at
Akmenė district municipality
Akmenė () is a city in northern Lithuania.
Following the discovery of large reserves of limestone and clay in the region, in 1947 construction work began on one of the largest cement production complexes in the Baltic States. Nearby, a new town ...
,
Šiauliai County
Šiauliai County () is one of ten counties in Lithuania. It is in the north of the country, and its capital is Šiauliai. On 1 July 2010, the county administration was abolished, and since that date, Šiauliai County remains as a territorial a ...
, northern Lithuania.
[
]
Geology
The Venta River valley exposes a record of Middle to Late Weichselian (ca 33,000 BP) environments beneath its modern floodplain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...
. An area of roughly 80 km2 in northwest Lithuania is underlain by up to 28 m of ancient lake sediments—brown, grey and greenish-black clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...
, 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 (chemistry), suspension with water. Silt usually ...
and fine sand with lenses
A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
of peat—buried beneath the uppermost Late Weichselian (Nemunas) till
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...
. At the Purviai outcrop
An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets.
Features
Outcrops do not cover the majority of the Earth's land surface because in most p ...
, pollen analysis
Palynology is the study of microorganisms and microscopic fragments of mega-organisms that are composed of acid-resistant organic material and occur in sediments, sedimentary rocks, and even some metasedimentary rocks. Palynomorphs are the mic ...
and radiocarbon dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for Chronological dating, determining the age of an object containing organic material by using the properties of carbon-14, radiocarbon, a radioactive Isotop ...
(33,540 ± 370 and 33,800 ± 460 calibrated years before present) reveal initially cold, wet periglacial
Periglaciation (adjective: "periglacial", referring to places at the edges of glacial areas) describes geomorphic processes that result from seasonal thawing and freezing, very often in areas of permafrost. The meltwater may refreeze in ice wedg ...
conditions dominated by open sedge (Cyperaceae
The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wikt:sedge, sedges. The family (biology), family is large; botanists have species description, described some 5,500 known species in about 90 ...
) communities, followed by slight climatic amelioration marked by park-tundra
In physical geography, a tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: #Arctic, Arctic, Alpine tundra, Alpine, and #Antarctic ...
vegetation of birch
A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains 3 ...
(''Betula''), pine
A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae.
''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as cu ...
(''Pinus'') and scattered spruce (''Picea''), showing that the climate warmed slightly from severe periglacial cold to a milder phase. Gravel layers within the sequence contain shells of the freshwater pearl mussel, '' Margaritifera margaritifera'', signalling clean, fast-flowing stream channels feeding into the lake basin. Together, these data show that the Venta valley remained largely ice-free until at least 33,000 BP and that the main glacial advance over North Lithuania did not occur until after 25,000 BP.
Environmental issues
Local water-quality surveys show that as the Venta flows through Kuršėnai, soluble phosphorus
Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...
roughly doubles—from about 0.069 milligrammes per litre (mg/L) upstream to 0.135 mg/L downstream—exceeding national water-quality limits. This rise in phosphorus matches a 15 % increase in chlorophyll a
}
Chlorophyll ''a'' is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light, and it is a poor absorber of green and near-green portions of the spectrum. Chlorop ...
(from 9.11 to 10.49 microgrammes per L), a standard indicator of algal biomass
Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...
, and is accompanied by lush growth of duckweed
Lemnoideae is a subfamily of flowering aquatic plants, known as duckweeds, water lentils, or water lenses. They float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. Also known as bayroot, they arose fr ...
species such as '' Lemna minor'' and '' Spirodela polyrhiza''.
Nitrate
Nitrate is a polyatomic ion with the chemical formula . salt (chemistry), Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are solubility, soluble in wa ...
concentrations also climb by roughly 50 %, from 2.27 mg/L upstream to 3.44 mg/L downstream, often exceeding the 2.3 mg/L guideline. Nitrite levels and organic pollution (measured as chemical oxygen demand) likewise regularly surpass safe thresholds. Although healthy aquatic ecosystems typically have a nitrogen-to-phosphorus ratio near 16:1, here the ratio is about 45:1 above the town and 27:1 below it—showing that nitrogen remains in excess even as phosphorus spikes.
Investigation points to two main pollution pathways: insufficiently treated sewage entering via the Urdupis stream, and nutrient-rich runoff from the Pakulmušiai/Kumulša pond system. Together, these inputs fuel heavier algal bloom
An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in fresh water or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompass ...
s, dense water-plant cover and an overall decline in water quality downstream of Kuršėnai.
A 2016 joint Latvian–Lithuanian study applied WFD mixing-zone guidelines (rules under the EU Water Framework Directive that allow a defined stretch of river immediately below a discharge to temporarily exceed pollution limits before returning to standard levels) to twelve wastewater
Wastewater (or waste water) is water generated after the use of freshwater, raw water, drinking water or saline water in a variety of deliberate applications or processes. Another definition of wastewater is "Used water from any combination of do ...
-discharge sites in the transboundary Venta River Basin. Under low-flow "worst-case" conditions they found that the river lengths needed to dilute total phosphorus and nitrogen discharges to EU standard levels varied from a few metres up to several hundred metres—and in small tributaries
A tributary, or an ''affluent'', is a stream or river that flows into a larger stream ('' main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which the ...
even became effectively "unlimited", meaning standards could not be met within the available channel. Of all the priority substances analysed, only nickel
Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...
required a particularly long mixing zone (over 900 m) to meet the newer bioavailable-nickel standard.
See also
* Ventas rumba
References
External links
{{Coord, 57, 23, 44, N, 21, 32, 40, E, region:LV_type:waterbody_source:kolossus-etwiki, display=title
Rivers of Lithuania
Rivers of Latvia
Venta River basin
International rivers of Europe