|Source elevation||78.2 m|
|Avg. discharge||283 m3|
Kymi river (Finnish: Kymijoki, Swedish: Kymmene älv) is a river in Finland. It begins from the lake Päijänne, flows through the provinces of Päijänne Tavastia, Uusimaa and Kymenlaakso and discharges into the Gulf of Finland. River passes the towns of Heinola and Kouvola. City of Kotka is located in the immediate vicinity of the river delta. The undisputed length of the river is 204 km, but the drainage basin (37,107 km2) extends to almost 600 km inside the Tavastia, Central Finland, Savonia and Ostrobothnia. The furthest source of the river is Lake Pielavesi, its furthest point being some 570 km away from sea measured by flow route.
Being one of the largest rivers in Southern Finland, Kymi is a major source of hydroelectricity. City of Kotka and towns of Kuusankoski, Myllykoski and Inkeroinen along the river are major centers of pulp and paper industry. Formerly river was extensively used for log floating.
Kymijoki river has 5 mouths. River is divided into two main branches near Kultaankoski rapids in Kotka, about 15 kilometers inland from the Gulf of Finland. Eastern branch is divided into Korkeakoski and Koivukoski branches; Koivukoski branch is again divided into two mouths (Langinkoski and Huumanhaara). Korkeakoski branch has only one rivermouth.
Western branch divides into Ahvenkoski and Klåsarö branches, both having one mouth.
The westernmost Ahvenkoski branch of the river served as a border between Sweden and Russia from 1743 to 1809. The parts of Finland east of the river were later called Old Finland. Old Finland was incorporated in the Grand Duchy of Finland in 1812.
Kymi river is very swift: it takes three days from a drop of water to run from lake Pyhäjärvi to sea. Its mean depth is 9 m (30 ft), and the deepest place is 29 m (87 ft)
Hydroelectric plants and rapids
In Kymijoki, there is 12 hydroelectric plants and several dams to regulate water level. First power plants were built is 1882. Canal and dam of Kalkkinen is used to regulate the water level at lake Päijänne. Hirvivuolle dam regulates water flow between eastern and western branches. Paaskoski dam near Tammijärvi regulates flow to Klåsarö branch and Strömfors dam regulates water level at Strömfors industrial area.
Upper and middle reaches:
- Kalkkistenkoski rapids and regulating dam (Asikkala)
- Jyrängönkoski rapids (Heinola)
- Vuolenkoski, hydroelectric plant (Iitti)
- Mankala, hydroelectric plant (Iitti)
- Voikkaa, hydroelectric plant (Kouvola)
- Pessankoski rapids (Kouvola)
- Lappakoski rapids (Kouvola)
- Kuusankoski, hydroelectric plant (Kouvola)
- Keltti, hydroelectric plant (Kouvola)
- Myllykoski, hydroelectric plant (Kouvola)
- Anjalankoski (Ankkapurha), hydroelectric plant (Kouvola)
- Piirteenkoski rapids (Kouvola)
- Susikoski rapids (At the boundary of Kouvola and ja Kotka)
- Ahvionkoski rapids area, elevation 1,9 m (At the boundary of Kouvola and Kotka)
- Kultaankosket rapids, elevation 1,5 m (At the boundary of Kouvola and Kotka)
- Hirvivuolle, regulating dam, built in 1933 (Pyhtää)
- Hirvikoski rapids (Pyhtää)
- Paaskoski, regulating dam, built in 1933(At the boundary of Pyhtää and Loviisa)
- Klåsarö (Loosarinkoski), hydroelectric plant (Pyhtää)
- Ediskoski, hydroelectric plant (Pyhtää)
- Strömfors, regulating dam, built in 1965 (Loviisa)
- Ahvenkoski, hydroelectric plant (At the boundary of Pyhtää and Loviisa)
- Pernoonkosket rapids area, elevation 5 m (Kotka)
- Laajakoski rapids (cleared away, Kotka)
- Koivukoski, hydroelectric plant and regulating dam (Koivukoski branch, Kotka)
- Siikakoski rapids (Koivukoski branch, Kotka)
- Kokonkoski rapids (Koivukoski branch, Kotka)
- Langinkoski rapids (Langinkoski branch, Kotka)
- Hinttulankoski rapids (Huumanhaara branch, Kotka)
- Korkeakoski, hydroelectric plant (Korkeakoski branch, Kotka)
Media related to Kymi River at Wikimedia Commons
- (Finnish) Kymi river