The aim of the study visit in September 2019 was to present and discuss Estonian RETROUT project sites where restoration works are planned. In addition, examples of previously constructed fish passes were visited and critical aspects of fish pass designs were presented.
Linnamäe hydropower station, situated on the lower stretch of the Jägala River, was originally built in 1922-1924. In 1941 it was partially destroyed and only in 2002 restored to present state. Linnamäe is the most powerful hydro-electric power station in Estonia. It is 11 m high and its capacity is 1.1 MW. There is no fish pass and it is deemed as a culturally valuable site. The dam lost its water permit in August 2019 and the obligation to provide fish passage stands. The main discussion on the site was related to conflicting interests regarding the site. Part of the dam was classified as culturally valuable and therefore optimal solutions for fish passage are hard to achieve. RETROUT project will provide plans how to remove the dam in a way that the cultural value is least affected. This work is currently in process.
Kotka dam was built in 1950 and operated as hydropower station until 1960. After that it provided water for a fish farm. The dam broke down in 2016 and it was not restored because it has no water permit. The dam was 3.5 m high originally and its capacity was 200 kW. The main discussion on the site was related to the cost of different proposed solutions. Secondly, it is evident that several local people are not satisfied with a loss of the lake and it was discussed how to communicate the solutions better so that the local community would appreciate the activities.
In frame of the RETROUT project two alternative solutions have been elaborated. Both include the remoal of the dam construction, but according to one solution a 76 m artifical rapid will be created (more expensive solution) or only the banks will be enforced.
Nõmmeveski power station was built in 1924 and operated until 1964. The wooden components broke down in 2010. Characteristics: the remaining height of the dam is 1 m. Since 2000 current owners of the dam have tried to get water permit to restore the hydropower station. The site does not have major conflicting issues. The step under the bridge cannot be lowered because the bride structures could become unstable. In frame of the RETROUT project the plan is to build 30 m long artificial rapid downstream from the bridge, enforce banks and deepen the concrete bottom under the bridge.
Other sites that were visited were the Joaveski hydropower station, Arbavere dam, Tapa fish pass, Kunda hydropower station, Old Kunda manor mill, Aravuse fish farm and hatchery and Sillaoru hydropower station.
You can read the summary of the study visit here.