There are three fish ladders (fishways) in the lower dams of the Kymijoki River, along which fish have the opportunity to ascend the dams
reproductive areas above. Two of these are located in Langinkoski branch and one in Korkeakoski branch.
A power plant is located in Korkeakoski, next to which a fishing road costing 1.5 million euros was opened in 2016. Korkeakoski fishway was one of the national
flagship projects in the fisheries strategy. The height of the fall on the fishway is 13 meters and its total length is 205 meters. Kalatie consists of 52 basins with a depth of 1.1 m. There is a power plant and a regulation dam built in 1933 in Koivukoski. Both have a fish ladder.
Functionality of fish ladders
Depending on the circumstances, the fish ladder will function either moderately or poorly. During low flows, no fish ladder works as desired. The stage of the Koivukoski regulation dam is functional, as long as a sufficient attraction flow flows through the dam.