The project is located at a narrow spot in the Indus River valley,at tarbela in Swabi, shortly located at the point from where the District haripur in hazara division starts. Here the river formerly split around a large island close to the left bank. The main dam wall, built of earth and rock fill, stretches 2,743 metres (8,999 ft) from the island to river right, standing 148 metres (486 ft) high. A pair of concrete auxiliary dams spans the river from the island to river left. The spillways, located on the auxiliary dams, in turn consist of two parts. The main spillway has a discharge capacity of 18,406 cubic metres per second (650,000 cu ft/s) and the auxiliary spillway, 24,070 cubic metres per second (850,000 cu ft/s). The outlet works are a group of four tunnels that have been cut through the valley wall at river right, for uses of hydropower generation and flow control. These tunnels were originally used to divert the Indus River while the dam was being constructed. The fifth river outlet is situated on the left side of the dam and was completed in April 1976.People from Hazara division living across river Indus gave sacrifices and left their lands and homes for the sake of dam construction.These people are now settled by government of Pakistan in Khala Butt Township Haripur, Pakistan.
A hydroelectric power plant on the right side of the main dam houses 14 generators fed with water from outlet tunnels 1, 2, and 3. There are four 175MW generators on tunnel 1, six 175MW generators on tunnel 2, and four 432MW generators on tunnel 3, for a total generating capacity of 3,478 MW. Tarbela Reservoir is 80.5 kilometres (50.0 mi) long, with a surface area of 250 square kilometres (97 sq mi). The reservoir holds 11,600,000 acre feet (1.43×1010 m3) of water, with a live storage of 9,700,000 acre feet (1.196×1010 m3). The catchment area upriver of the Tarbela Dam is spread over 168,000 square kilometres (65,000 sq mi) of land largely supplemented by snow and glacier melt from the southern slopes of the Himalayas. There are two main Indus River tributaries upstream of the Tarbela Dam. These are the Shyok River, joining near Skardu, and the Siran River near Tarbela.