Sieniawa Lake was created in 1978, when a dam was built on the Wisłok river in Sieniawa, on the 172.8th kilometre of its length. The dam is 174 metres long and 38 metres high. On the top, it is 8.5 metres wide and the regional road no. 889 from Rymanów to Szczawne runs through it. There is a small hydroelectric power station on the dam. The lake has the capacity of around 14.2 million cubic metres, and its maximum depth is almost 29 metres. It is used for preventing floods, water retention and recreation, as well as supplying water for Rymanów and Iwonicz Zdrój.