Läsäkoski was renovated in three separate steps in 2004 – 2009. Renovation, especially this fierce, leaves marks which are shoking to look at. But the nature tends to fix the marks made by human hands. The nature of these renovations is restoring in type and the target is to get back diversity of the nature rapids. If this goes right it would bring better possibility for lake migrating brown trout to reproduce in Läsäkoski rapid.