The Amirkabir dam is the first multi-purpose dam in Iran and located at 25 Km of northern Karaj, along Karaj-Chalus main road. It is charged by Karaj River and its branches. The lake length is almost 5.5 Km (complete storage). Karaj dam is an arc concrete type and its construction was started in 1952 and finished in 1962. Dam height is 150m and the volume of reservoir is 1800 mm3. The crest length is 390m. Right dam abutment lies on an Eocene-Oligocene monzogabbro mass and left dam abutment has been made by Karaj tuff Formation.