Dam safety

An accident involving a dam could cause major damage, which is why a great deal of attention is paid to dam safety.

In addition to hundreds of dams stretching across rivers and lake outlets, waste dams and flood embankments are also found in Finland. Waste dams are built in connection with mines, for instance, where they form wastewater basins.

The Dam Safety Act and Decree contain provisions on dam safety. Under the act, dam safety is supervised by the authorities, in practice the Centre for Economic Development, Transport and the Environment (ELY Centre) for Kainuu.

According to the Dam Safety Act, the owner of a dam is responsible for ensuring that the dam is safe and operates as designed. Among other things, the dam owner must prepare a monitoring programme for the dam and have it approved by the authorities.

Dams are divided into three classes according to the scale of the damage that could be caused by a potential accident. The highest hazard class comprises 56 dams in lakes and rivers and 30 waste dams, which are subject to more stringent safety requirements than those in the other classes. There are altogether around 450 classified dams, in addition to which thousands of unclassified installations are found in Finland.

While the principles of and legislation on dam safety are rather similar in Finland and Norway, Sweden is in the process of developing its legislation in the same direction.

Image: Built in the 1920s, the regulating dam at Imatrankoski rapids is a significant cultural history site. Shows where the rapids are allowed to run free are organised in summer. © Eija Isomäki, ELY Centre