Bileca Lake was created artificially by constructing of the Grančarevo dam on the river Trebisnjica near the town in 1968. The dam is 123 meters high and 439 meters wide. At the bottom of the lake there are abandoned villages that were evacuated during the construction of hydroelectric power stations Trebinje I. Cemeteries, churches and roads got flooded by the lake.
Bileca Lake is a large man made lake on the Trebijanca River, which was created in 1968. This is the only source of surface water in an area which is subject to extreme weather conditions in winter and also in summer. Cepelica is its small tributary in Bileca Rudine and is stated to be the best known subterranean river in Bosnia and Herzegovina. It lies in the Upper and central part of Trebsinjica valley 17 km from Trebinje is one of the largest lakes in the country.
The landscape of the district where the lake is situated consists of lime stone mountains with bare karst formations