Maintenance Halt Dries Viinikanjoki, Threatens Wild Trout

A Parkano power plant halted water discharge for two days during the trout protection period that began on 1 September. The stoppage left stretches of Viinikanjoki’s riverbed exposed and emptied a neighbouring pond. YLE reported the incident.

Local anglers who inspected the stream raised alarms about the river’s prized wild trout. Timo Ojalainen, chair of the Parkano anglers’ club, said he had never seen the bottom visible in his 60 years by the water. A 2016 survey found Viinikanjoki’s trout descend from the river’s original stock and reproduce naturally; anglers say one of the river’s trout has an estimated conservation value of €2,440.

Experts and authorities are now assessing ecological damage and the legality of the stoppage. Jarmo Pautamo, who has studied and restored rapids for decades, warned that benthic fauna such as mayfly larvae may have been wiped out in places. That would reduce food for fish and could delay ecosystem recovery until next summer. The Permit and Supervision Agency (LVV) is investigating whether Käenkosken power plant complied with its 1965 water permit; the plant did not notify LVV before stopping discharge.

The operator says the two-day halt was for maintenance. Divers inspected underwater on the first day and workers sealed the dam on the second. Flow returned only after several days because river levels are unusually low this year. No dead fish have been reported so far, but anglers remain worried about juvenile trout and habitat loss.

The stoppage follows a wave of maintenance-related drainings in the region, including inspections that emptied Tammerkoski the Tammerkoski drainings last month.