The state aims to dismantle the small power dams in the rivers in order to strengthen the fish stocks. This option is being considered at the Kaustinen Pirttikoski dam.
Based on the plan commissioned by ely, the Pirttikoski power shovel dam located in Kaustinen could be replaced with a bottom sill.
In this way, the landscape of the area would not change even if the power shovel dam were dismantled. The threshold below the water surface would be built below the current power dam. It would maintain the current level of the water level most of the time.
Varsinais-Suomen ely-keskus has commissioned a preliminary plan for the demolition of the dam located in Perhonjoki near the center of Kaustinen.
Beach residents support this option, as the landscape would remain as it is now. In the opinion of the residents, the familiar power plant buildings should also be preserved.
– The discussion took place, among other things, about placing a beach and a shelter in the area for the villagers to use.
In the other alternatives drawn up from the renovations, the bottom sill was placed higher than the current power shovel, which would have made the rapids area longer.
– Elsewhere in Perhonjoki, there are plenty of rapids and rapids. I personally feel that the will of the locals to preserve the river landscape could be a reasonable and feasible option. Koski is in such a central location that the landscape is of great importance.
The rise of fish would be easier
Dismantling the power dam would help migratory fish to rise, even if a new dam were built in the same place.
A concrete regulation or power dam is located high above the water surface. The threshold to be built in its place, on the other hand, resembles the neck of a natural rapid and remains under water and does not restrict the passage of aquatic organisms like a power dam.
Tamminen says that the entire stream water nature would benefit from unloading, but especially the strong population of sea trout that once lived in Perhonjoki would recover. You could also go to the salmon farm.
According to the cost estimate of the preliminary plan, the construction of the bottom threshold will cost 400,000 euros. Tamminen estimates that the project could at best be completed in 2-3 years.
Another option is that the dam is not dismantled, but Killin Voima continues to use the power plant, but builds a fishway that goes around the dam.
Next, we should get clarity on the role and willingness of Kaustinen and the other municipalities along the river, says chief inspector Perttu Tamminen.
Kaustinen municipality could be the owner of the area and the new bottom dam, as well as the holder of the water permit required for dismantling.
If it is decided to dismantle the dam, it must be claimed from the owner, Killin Voima. The state pays half of the redemption price.
The state-funded NOUSU program aims to strengthen endangered fish stocks by dismantling small power shovels and then rehabilitating the rapids.