This year marks the 70th anniversary of the start of the building of the Hydroelectric Power Station in Medvode. The station not only generated the much needed electrical energy, but its construction also had an impact on the general appearance of the region by building a dam across the river Sava and creating Zbilje Lake. This month's archivalia is dedicated to documents that bear witness to the construction of this power station in Medvode.

The river Sava was important to local population even before the industrial period. Its current was used to transport various goods and to provide power for water mills and sawmills located alongside the river. Later on, the river began to be seen also as a potential source for the generation of electrical power. First power stations in Upper Carniola started to be built already before WWI, but their construction was abruptly interrupted by the war and only continued after WWII.

The construction of the hydroelectric power station began in 1947. The contract for the project was signed on January 31, 1947 between the two contracting parties; the General Directorate for Electrification and Electro Industry as the client and the Project Office of the People's Republic of Slovenia as the design engineer. The contract set implementation tasks: technical expert's report, consultations, technical supervision, testing and start of the operation, instructions to the client for the protection of the object before the start of the operation or in case of work interruption, as well as all other project implementation related conditions.

Once the work started, instructions about technical documentation for the buildings changed several times. During the construction, decisions were issued to approve technical documents for the basic investment object of the Medvode Hydroelectric Power Station: in 1947 prior authorization for the construction was received, in 1949 the project was approved: that same year the project Hydroelectric Power Station on the river Sava in Medvode was confirmed, which in fact was the main body of the project. Apart from building the power station, some extra work was done within the framework of the project as well; they reconstructed the wooden bridge across the Sava river near Smednik, they built driving station and waterworks, regulated Sava river, and built the connector for connecting the power station to power line as well as several other replacement facilities and residential houses. Construction costs changed throughout the entire course of work which is why the 1953 investment study saw the costs corrected by means of special factors, so as to make the costs similar to the price that was set in the 1949 expert study.

The building itself was hard and also dangerous since the machinery that is known today did not exist at the time. Almost all the work was done manually. The workers worked for ten hours or more, sometimes even on Sunday. The difficulty of work let to some work-related fatal injuries. Workers came from Medvode and the neighbouring towns, there were also some coming from other Yugoslav republics; the latter lived in barracks not far from the construction site. Also working on the site were political prisoners who were situated in the camps nearby. The 1952 documents reveal that residential flats had to be provided and built for the men working at the station and for those operating the driving station. The space chosen for the building of this residential area was located along the Ljubljana-Kranj road, south of the village Svetje.

The work was done in several stages. First, the right bank building was built and then the middle pier. Water was directed through the right spillway and then the left bank building was built. Workers worked all year around. Enormous amounts of different materials were used, among them 900 tons or 200 wagons of reinforced concrete. Special railway tracks and wagons were used for the transportation of the material and special lifts were employed to lift it. It took more than a million working hours to build the power station. Once that was done, there came hydro mechanical equipment (spillway gates, tracks, wheels …). In 1953, the first gate was installed into the spillway. Some of the houses above the dam were overflowed and the owners of these houses were moved to new homes. By damming the river, a five-kilometre long lake was accumulated behind the dam – Zbilje Lake. Lastly, they installed the machinery needed for the operation of the power station (turbines, generator, rotor …).

The power station was ceremoniously opened on August 1, 1953. On December 1 that same year the station began to operate regularly as run-of-the-river power station with potential for daily peak power supply. The dam has gates and is built 150 metres above the bridge that connects Medvode and Pirniče. It consists of a building on both river banks and a pier in the middle of the river. All three of the objects create two spillways parted by two-part gates. The two buildings on both river banks include engine room with a generator set. The power station has two turbines. It had to put up permanent markings for the highest and the lowest level of water and provide a system for timely alarm for locations where water level fluctuations could potentially threaten the safety of people, animals, traffic …

Hydroelectric power station also changed everyday life in Medvode. One of the more prominent changes was the creation of the lake, which today, together with the power station, is regarded as one of the sights of Medvode.

Jasmina Kogovšek