The Daugava (Latgalian: Daugova; Polish: Dźwina; German: Düna) or Western Dvina (Russian: Западная Двина, romanized: Zapadnaya Dvina; Belarusian: Заходняя Дзвіна; Estonian: Väina; Finnish: Väinäjoki) is a large river rising in the Valdai HillsofRussia that flows through Belarus and Latvia into the Gulf of Riga of the Baltic Sea. The Daugava rises close to the source of the Volga. It is 1,020 km (630 mi) in length,[1] of which 352 km (219 mi) are in Latvia[2] and 325 km (202 mi) in Russia. It is a westward-flowing river, tracing out a great south-bending curve as it passes through northern Belarus.
Latvia's capital, Riga, bridges the river's estuary four times. Built on both riverbanks, the city centre is 15 kilometres (9.3 mi) from the river's mouth and is a significant port.
According to Max Vasmer's Etymological Dictionary, the toponym Dvina cannot stem from a Uralic language; instead, it possibly comes from an Indo-European word which used to mean riverorstream.[3] The name Dvina resembles strongly Danuvius which itself derived from the Proto-Indo-European *dānu, meaning "large river".
The Finno-Ugric names Vēna (Livonian), Väinajogi (Estonian), and Väinäjoki (Finnish) all stem from Proto-Finnic *väin, meaning "a large, peacefully rolling river".
[edit]The Swedish army bombarding the fortress of Dünamünde at the Daugava's estuary in Latvia
Humans have settled at the mouth of the Daugava and along the shores of the Gulf of Riga for millennia, initially participating in a hunter-gatherer economy and utilizing the waters of the Daugava estuary for fishing and gathering. Beginning around the sixth century CE, Viking explorers crossed the Baltic Sea and entered the Daugava River, navigating upriver into the Baltic interior.[4]
In medieval times, the Daugava was part of the trade route from the Varangians to the Greeks, an important route for the transport of furs from the north and of Byzantine silver from the south. The Riga area, inhabited by the Finnic-speaking Livs, became a key location of settlement and defence of the mouth of the Daugava at least as early as the Middle Ages, as evidenced by the now destroyed fort at Torņakalns on the west bank of the Daugava in present-day Riga. Since the Late Middle Ages, the western part of the Daugava basin has come under the rule of various peoples and states; for example, the Latvian town of Daugavpils variously came under papal, Slavonic, Polish, German, and Russian rule until the restoration of the Latvian independence in 1990 at the end of the Cold War.[citation needed]
The river began experiencing environmental deterioration in the Soviet era due to collective agriculture (producing considerable adverse water pollution runoff) and hydroelectric power projects.[5] This is the river that the Vula river flows into.
Upstream of the Latvian town of Jekabpils, the river's pH has a characteristic value of about 7.8 (slight alkaline). In this area, the concentration of ionic calcium is around 43 milligrams per liter, nitrate is about 0.82 milligrams per liter, ionic phosphate is 0.038 milligrams per liter, and oxygen saturation is 80%. The high nitrate and phosphate load of the Daugava has contributed to the extensive buildup of phytoplankton biomass in the Baltic Sea; the Oder and Vistula rivers also contribute to the high nutrient loading of the Baltic.[citation needed]
In Belarus, water pollution of the Daugava is considered moderately severe, with the chief sources being treated wastewater, fish-farming, and agricultural chemical runoff (such as herbicides, pesticides, nitrates, and phosphates).[6][7]
