The river Trešnjica springs on the southwest side of Povlen at a height of 1185 m, and flows into the Drina near Gornja Trešnjica at a height of 180 m. The distinctly gorge-like valley of Trešnjica is partly canyon-like in appearance. In the middle course, it flows through a picturesque canyon close to 6 km long, which is cut in an 800-1000 m high area. In the Trešnjica canyon, it receives the largest right tributaries - Sušica and Tribuća.