Hydropower company investigates fish deaths in Kotka following reduced water flow

A hydropower company operating in Kotka is currently investigating incidents related to fish deaths that occurred in early September. Hundreds of salmon fry were found dead in the Langinkoski rapids of the Kymijoki River, trapped in side channels, pools, and on dry land after the upstream Koivukoski power plant reduced water flow.

Subsequent investigations revealed that the water discharge was below the permitted levels. Initially reported to be 20 cubic meters per second, the actual flow was observed to be only 15 cubic meters per second. Matti Vaittinen, a water resources manager at the Southeast Finland ELY Center, noted that an issue with the power plant’s automation was responsible for the miscalculation.

As a result of the reduced flow, more land area was left dry than would have been permissible under normal circumstances, impacting the number of fish that became stranded. Concerned citizens, including anglers and nature enthusiasts, reported to the hydropower company that water levels appeared lower than expected for that time of year.

The company promptly began examining the flow issue, discovering a fault in the dam’s measurement system. After rectifying the situation and notifying relevant authorities, it was clarified that the water flow had been insufficient for several days.

Authorities have since issued a request for clarification regarding the inadequate flow, leading to an inquiry by the ELY Centers regarding compliance with permit conditions and the extent of fish casualties. By the end of the year, investigations will determine whether the insufficient flow was caused by accident, negligence, or deliberate action. If deemed an accident, measures will be explored to prevent similar occurrences in the future.