Kymi (river)

Kymi (river). The Kymi, known in Finnish as Kymijoki, is a major river in southern Finland, flowing from the large lake Päijänne into the Gulf of Finland. It is historically significant as a border and transport route and is notable for its powerful rapids, which have been harnessed for hydroelectric power. The river's basin is one of the most densely populated and industrialized regions in the country.

Geography and course

The river originates from the southern end of Päijänne, Finland's second-largest lake, near the city of Lahti. It flows generally southward through the regions of Päijät-Häme and Kymenlaakso, passing towns such as Kouvola and Anjalankoski. The course is characterized by several large rapids, including the Mankala Rapids, before it bifurcates into two main branches near the coast. The western branch flows past the city of Kotka, while the eastern branch reaches the sea at the town of Pyhtää. The river ultimately empties into the Gulf of Finland via a broad, archipelago-filled estuary.

Hydrology and flow

The Kymi has a substantial and relatively stable flow, with an average discharge of approximately 280 cubic meters per second at its mouth, fed by the vast Päijänne drainage basin. The river system includes numerous lakes, such as Pyhäjärvi and Kymijärvi, which help regulate its flow. Seasonal variations occur, with higher flows typically during the spring snowmelt and the autumn rains. The river's hydrology was fundamentally altered in the 20th century by the construction of several hydroelectric power plants, which tamed its historic rapids and created reservoirs.

History and significance

Historically, the Kymi river formed part of the border between Sweden and Russia following the Treaty of Nystad in 1721, a status it retained until the Finnish War of 1808–1809. The river was a vital route for the transport of timber from the inland forests to the coastal sawmills, fueling the early industrialization of the region. During the Winter War and Continuation War, the river line was a strategically important defensive position for the Finnish Army against the Soviet Union. The area around the river mouth was also the site of the Battle of Svensksund in 1790.

Economy and use

The river's economy has long been dominated by the forest industry, with major paper mills and pulp mills located in Kotka, Kuusankoski, and Kymi (now part of UPM-Kymmene). Its rapids provided the foundation for industrial development, with hydroelectric power generation beginning in the early 20th century at plants like Kymin Koski. The river remains crucial for log driving and process water, although its role has diminished. The ports of Kotka and Hamina, situated near the estuary, are among Finland's most important for export and import, handling goods from the hinterland.

Ecology and environment

The river's ecosystem has been significantly impacted by centuries of industrial activity, particularly from pulp and paper industry effluent, though water quality has improved markedly since the late 20th century due to advanced wastewater treatment. The estuary and archipelago form an important habitat for migratory birds and fish species like salmon and sea trout, whose populations are supported by stocking programs. Conservation efforts focus on river restoration projects and maintaining the ecological status of the watercourse under the European Union Water Framework Directive.

Category:Rivers of Finland Category:Kymenlaakso