Heavy August rain pushes northern rivers to record levels

Heavy rain has caused rivers in northern Finland to rise to record levels, with flood and rainfall warnings issued for more than 20 municipalities in western North Ostrobothnia, Yle reports.

Rain expected on Thursday and Friday is forecast to raise water levels and flows further, particularly in the Iijoki River. Rivers in several parts of North Ostrobothnia and Lapland are unusually high for this time of year.

According to the Finnish Meteorological Institute’s 30 day weather data, it has rained on almost every day this month. Rivers across a wide area are more than a metre higher than normal. The Simojoki River is about 1.5 metres above its usual August level.

The Simojoki last reached a similar level in autumn 1992, according to Niina Karjalainen, a senior water management specialist at the Lapland Centre for Economic Development, Transport and the Environment. The Tornionjoki River is also unusually high, with the reading at the Kukkolankoski monitoring station more than a metre above the normal August level.

Water levels in the Kalajoki and Iijoki river basins are higher than ever recorded at this time of year. Flows in the Iijoki have reached record levels for the season in several places.

Flooding cuts roads and transport links

Authorities in North Ostrobothnia have not reported major flood damage, but water has cut off and damaged smaller roads. In Vaala, flooding on the Mulkuanjoki River has cut the road connection to three homes.

Continued rain and rising water levels are also threatening holiday homes in some parts of North Ostrobothnia. Docks and boats have already been damaged by the rising water and stronger currents, says water management specialist Riku Sanaksenaho.

Sanaksenaho said people should monitor docks, other shore structures and boats in flood prone areas, even though residential buildings have not been flooded. Smaller channels can reach their capacity even when there are no problems in the main river channel.

He also urged people on the water to take possible strong currents into account and to secure loose items near the shore.

River restoration work suspended

Water levels in the Tengeliönjoki River, a tributary system of the Tornionjoki, have risen in places close to the levels seen during last spring’s floods. The situation has forced the suspension of river restoration work in Ylitornio.

The work was intended to restore smaller tributaries and open migration routes for fish, but the high water levels could postpone it until next summer.

“The rivers should now be at their lowest. There is a fear that the work cannot continue before next summer. The rivers are full to the brim,” said Marko Kangas, project coordinator for the TRIWA project.

The project is described as Europe’s largest river restoration effort and aims to open thousands of kilometres of fish migration routes in the Tornionjoki Valley in Finland and Sweden.

Power plants operating at full capacity

Exceptional rainfall and the high volume of water in the Iijoki are also affecting PVO-Vesivoima’s power plants, said Antti-Pekka Sipola, the company’s head of operations and development.

“The power plants are operating at full capacity, and all of the Iijoki plants are also releasing water through spillways,” Sipola said.

The company operates five power plants on the Iijoki. According to Sipola, flows have already reached record levels for this time of year in some places.

Further south in North Ostrobothnia, rainfall has stopped in the Siikajoki, Pyhäjoki and Kalajoki river areas, and the flood situation is beginning to ease.