Conavalla also sits in another broad horseshoe around the Glendalough valley, with the hydroelectric station at Turlough Hill , and the mountains of Camaderry , Lugduff , and Mullacor . Conavalla's large boggy massif dominates the head of the Glendalough valley stretching from its summit at the far-west side of the head of the valley, to Lough Firrib on the east-side. The massif also includes Three Lakes to the north of the summit of Conavalla.