The Lake Zavoj, located in the Southeast Serbia, was formed in 1963 when the erosion of the river bank blocked the flow of the Visočica River.
The national government decided to reconstruct the river barrier created by erosion into a dam and construct a hydro-electric power plant Pirot (HPP Pirot), which started working in the 1990. The HPP experienced the lack of water to fulfill its electricity production capacities. In order to bring additional water to the HPP, the government proposed construction of re-routing tunnel that would bring Toplodolska River towards the Lake Zavoj. The tunnel construction started in the 1990's. The Toplodolska River, located in the territory of the Stara Planina Nature Park, is tributary to Temska River already affected by the HPP Pirot.
The community of village Temska supported by NGOs, local professionals and municipality of Pirot have opposed the re-routing project by organizing protests, signing petitions and blocking the roads.
The citizens’ main arguments were that the project will dry out the river they depend on and that it would end up in land expropriation. The project was stopped, with only 50% of the tunnel constructed. In 2004 and 2007, there were two attempts to finish the tunnel, which once again provoked protests. In January 2007, the citizens of village Temska boycotted the local elections. Later same year, several thousand people blocked the local roads in length of 300 m using 70-80 tractors and 30 cars. Even though the Ministry of Water Management, Mining and Energy and the Environmental Ministry gave their permits to the HPP Pirot, the municipal government of Pirot found inadequate the project EIA study and supported citizens by not issuing necessary permits for tunnel construction, including land expropriation. Moreover, the Pirot municipality asked the Serbian government to delete the project from the National spatial plan. The project is currently stopped, however it is included in the new proposal of the Regional Spatial Plan.