Vlasina Lake

There are two permanent islands on the lake, along its eastern coast: Dugi Del (7.84 hectares or 19.4 acres) and Stratorija (1.82 hectares or 4.5 acres).[1] Both islands are covered with green areas and forests.[6]

Along with those islands, one of the lake's most famous features are the floating islands. They didn't exist in the former peat bog and began appearing after 1948, when the lake was created. They are formed when at high water level, loose chunks of peat 0.5 to 2 metres (1 ft 8 in to 6 ft 7 in) thick break off the shore. It is estimated that the peat chunks took 5,000 years to form. There are up to 30 floating islands at the time. Driven by the wind, they float from one shore of the lake to another, carrying the flora and fauna, and serving as shelter and a food source for fish. For that reason, they are an attractive target for fishermen, however it is forbidden to visit them or disturb them because of the unique animal and plant ecosystems, though walking on them is practically impossible since they don't have solid ground.[5][6]

The largest such island has an area of 2 hectares (4.9 acres), it is referred to as "Moby-Dick" by the local population, and is the largest such formation in the Balkans. It is overgrown with dense vegetation, including birch trees. Carried by the water currents and strong winds, in 2016 "Moby-Dick" almost reached the shore near the "Vlasina" hotel, softly attaching itself to the bank and becoming a major tourist attraction. Previous such occurrence happened in the mid-1990s. During the extremely low water level, it was reported in August 2018 that the island was partially stranded on dry ground. Another major storm and strong wind, detached Moby-Dick on 15 August 2020, which after four years continued to float on the lake surface.[5]

The temperature of the water reaches 21 to 23 °C (70 to 73 °F) in the summer months,[7] making for refreshing swimming. It freezes in the winter and the ice crust can be as much as 2 metres (6 ft 7 in) thick.[8] The temperature also varies with location and depth. In the village of Topli Dol south of the lake, there is a water factory "Vlasinka", producing high-quality mineral water called "Vlasinska Rosa", a renowned brand in Serbia. It was purchased by The Coca-Cola Company in 2005.[9]

There are some 70 natural water springs in the lake area. The best known kladenac (cold water spring), noted for its cold water and most visited by the tourists, is the Sveti Nikola (Saint Nicholas) spring.[5]

The lake's surroundings are a mixture of meadows and high-altitude forests, especially birch, beech, pine and juniper (the former two indigenous, and the latter chiefly introduced by afforestation of the western shore). The indigenous trees downy birch and yellow beech (characteristic for its ever-yellow leaf color) stand out among the species of trees.[3]

Sundew is the only carnivorous plant in Serbia and is unique to the Vlasina region.[3] It is estimated that over 300 herbal species in the region are medicinal.[5]

The lake is home to 16 species of fish.[10] These include:[5] Brown Trout, Ohrid trout, Rainbow trout, European perch, European eel, Eurasian minnow, Mediterranean barbel, grass carp, common carp, crucian carp, Prussian carp, tench, roach, common chub, pumpkinseed and others. Ohrid trout was stocked and it successfully adapted to the environment, making it a popular for fishing.

Birds includes gray heron, mallard, tufted duck and cormorant.[3] Mammalian species include wild boars, wolves, foxes, hares, roe deer and feral horses.[10]

By the decision of Government of Serbia in 2006, the Vlasina region is protected as a nature preserve of special interest at category I. The total protected area is 12,741 hectares (31,480 acres), of which 9.6 hectares (24 acres) are in the 1st level of protection (islands of Dugi Del and Stratorija), 4,354 hectares (10,760 acres) in the 2nd level and 8,377 hectares (20,700 acres) in the 3rd level of protection.[1]

In the summer of 2018, both the citizens and the tourists, so as the administration of the Surdulica municipality reported the record low water level in the lake. Municipality issued a statement saying that the sudden water discharge at the dam may destroy the part of the plant and animal life in the lake. Numerous boats and barges were stranded, such as the "Moby-Dick", the largest floating island on the lake. It is estimated that the level fell for up to 5 m (16 ft). The Elektroprivreda Srbije (EPS), a state-owned electric utility power company admitted that they are forced to discharge larger amounts of water from the lake because of the repairs on one of the four Vrla hydro power plants, but that no harm will be done. The reconstructed power plant, Vrla I, was built in 1955 and it was stated that the renovation "was necessary" and that the works will be finished by October 2018.[5]

By October other floating islands got stranded, the boat traffic was made more difficult and the water level dropped by 4 to 7 m (13 to 23 ft). In the shallower bays the water receded significantly and they have been described as "desolate". The EPS claimed that the works will last for only 30 days and that water level has to be reduced to 1,206.5 m (3,958 ft) but continued to claim that no harm will be done. University of Belgrade Geography Faculty contradicted the company's claim. The longer floating island are stranded, the greater is the chance that they will not "unhinge" from the bank when the water rises. Head of the local protection enterprise accused EPS of lowering the water level to produce more electricity rather than to renovate the plant. The EPS stated that "in the period to come", they will start to pump the water from the Lisine Lake into the Vlasina.[12]