History of river and lake regulation

Lieksankosken voimalaoitos, suunnittelija Alvar Aalto

The earliest regulation projects involved lowering the water level in lakes to gain more fertile agricultural land, whereas brooks and rivers were harnessed to run hundreds of water mills.

The clearing of rivers began early, both to reduce flooding and to open up rivers for timber floating. In practice, all rivers and even many brooks in Finland were used for this purpose.

While the first hydropower plants in Finland became operational in the late 19th century, a veritable building boom started after the Second World War. Power plants were designed by famous architects, such as the Pamilo power plant in Joensuu designed by Alvar Aalto.

Flood protection expanded in the 1950s, especially along Ostrobothnian rivers prone to flooding. Initially, rivers were cleared and embankments were built on their shores, but it was soon realised that this was not enough and the water levels also had to be regulated. In those days, however, the law only permitted regulation for the needs of hydropower generation. In the Water Act passed in 1962, flood protection was added to the grounds for regulation, also making it possible to build artificial lakes.

Today’s regulation projects attempt to achieve multiple objectives by promoting hydropower generation, flood protection and recreational use of waters simultaneously.