Tarbela Dam is an earth and rock fill dam on the Indus River in Haripur District, Khyber Pakhtunkhwa. Tarbela was completed in 1976, stands 143 metres high, and carries 4,888 MW of installed power capacity.
Tarbela Dam is the largest dam in Pakistan and the largest earth filled dam in the world, a ranking set out beside every other major entry in this list of dams in Pakistan. This article gives Tarbela Dam’s river, district, height, crest length, storage capacity and power output, then explains why the dam was built under the Indus Waters Treaty, how the extension projects raised its generating capacity, and how much of the reservoir sedimentation has taken away.
Tarbela Dam Facts and Key Figures
The table below lists the attributes of Tarbela Dam that readers ask about most often. Storage rows carry both the original design value and the current sedimentation adjusted value, because the two differ by roughly a third and older sources still quote the design figure.
| Attribute | Tarbela Dam |
|---|---|
| River | Indus River |
| Location | Haripur District, Khyber Pakhtunkhwa |
| Distance from Islamabad | About 105 km northwest |
| Dam type | Earth and rock fill embankment |
| Height | 143 m (470 ft) above the riverbed, 148 m (485 ft) from the deepest foundation |
| Crest length | 2,743 m (9,000 ft) |
| Gross storage capacity | 11.62 MAF (14.3 billion cubic metres) at 1974 design |
| Live storage capacity | 9.68 MAF at design, about 5.7 to 6.8 MAF today |
| Installed power capacity | 4,888 MW |
| Maximum lake level | 1,550 feet |
| Reservoir surface area | About 250 square kilometres |
| Catchment area | About 169,600 square kilometres |
| Construction period | 1968 to 1976 |
| Completed | 1976 |
| Built by | WAPDA, with the Tarbela Dam Joint Venture led by Impregilo |
On Which River Is Tarbela Dam Built?
Tarbela Dam is built on the Indus River, the longest river in Pakistan and the trunk of the Indus basin. The dam sits about 50 kilometres downstream of the point where the Indus leaves its Himalayan gorges and enters the plains, which is why the site was chosen.
The Indus rises in Tibet, runs through Gilgit-Baltistan, and collects the Kabul, Jhelum, Chenab, Ravi and Sutlej before reaching the Arabian Sea. Snowmelt and monsoon rain concentrate the flow into a few summer months, so the river delivers most of its water when crops need it least. Tarbela Dam exists to hold that summer surplus and release it during the dry rabi season.
The catchment feeding Tarbela reservoir covers about 169,600 square kilometres of mountain terrain. That catchment carries an exceptional sediment load, and the sediment is the single biggest constraint on the reservoir’s working life.
Where Is Tarbela Dam Located?
Tarbela Dam is located in Haripur District of Khyber Pakhtunkhwa, near the town of Tarbela and close to Topi in Swabi District. The dam lies about 105 kilometres northwest of Islamabad, about 30 kilometres from Swabi, and about 125 kilometres from Peshawar.
The reservoir itself stretches roughly 80 kilometres upstream along the Indus and covers about 250 square kilometres at maximum lake elevation of 1,550 feet. Because the reservoir extends past district boundaries, some sources list Tarbela under both Haripur and Swabi. The dam structure and powerhouse are in Haripur District.
The site sits at the hinge between the mountains and the Punjab plain, the same physical position that gives the whole Indus corridor its strategic value and underpins the geographical importance of Pakistan.
Why Was Tarbela Dam Built?
Tarbela Dam was built to replace the irrigation water Pakistan lost under the Indus Waters Treaty of 19 September 1960. The treaty gave India the three eastern rivers, the Ravi, Beas and Sutlej, and gave Pakistan the three western rivers, the Indus, Jhelum and Chenab.
Losing the eastern rivers cut off canals in eastern Punjab that had been running since the British canal colonies. The treaty therefore came with the Indus Basin Project, a World Bank coordinated programme of replacement works that built link canals, barrages and two large storage dams. Mangla Dam on the Jhelum was the first, completed in 1967. Tarbela Dam on the Indus was the second and by far the larger.
Before Tarbela, Pakistan depended on unregulated river flow more than twenty years after independence. Crops failed in the critical growing season not because the Indus lacked water but because the water arrived in the wrong months. Regulating that flow for the canal network, described in full in the irrigation system of Pakistan, was the primary purpose. Hydroelectric generation and flood control were secondary objectives.
How Was Tarbela Dam Built?
Construction of the main works began in 1968 and the dam was completed in 1976 at a cost of about US$1.49 billion. The main embankment was substantially finished by mid 1974, which is when the reservoir was first impounded, and full project completion including the later stages ran to 1984.
The World Bank provided the principal financing through a bank loan approved in 1968 and two International Development Association credits. The Water and Power Development Authority executed the project for the Government of Pakistan under a single civil works contract. The contractor was the Tarbela Dam Joint Venture, a consortium of Italian, French, German and Swiss civil engineering firms led by the Italian company Impregilo.
Structure of the Dam
The main embankment reaches 143 metres above the riverbed and runs 2,743 metres along its crest, and the fill required about 138 million cubic yards of earth and rock. Two auxiliary embankments flank the main dam on the left bank, standing 105 metres and 67 metres high.
Those auxiliary embankments carry the two spillways. The service spillway has seven gates and a discharge capacity of 650,000 cusecs, and the auxiliary spillway has nine gates and can pass 850,000 cusecs. Four tunnels were driven through the right bank valley wall, three for power generation and one for irrigation releases.
What Is the Storage Capacity of Tarbela Dam?
Tarbela Dam had a gross storage capacity of 11.62 million acre feet, equal to 14.3 billion cubic metres, and a live or usable capacity of 9.68 million acre feet when the reservoir was commissioned in 1974. Live capacity is the figure that matters for irrigation, because it is the volume that can actually be released.
Sedimentation has taken a large share of that live capacity away. Sources differ on how much remains. Dawn reported in October 2025 that Tarbela’s live storage had fallen to 5.73 MAF, a reduction of roughly 40 percent, and estimated about 10 billion tonnes of accumulated silt. Wikipedia, citing an earlier assessment after 35 years of operation, puts the figure at about 6.8 MAF and the loss at more than 33.5 percent. The honest statement is a range: Tarbela’s live storage now sits somewhere between about 5.7 and 6.8 MAF depending on the survey year and the source.
This is why so many contradictory Tarbela numbers circulate. Pages quoting 9.68 MAF are quoting the 1974 design value, not a current measurement. The same problem affects the national total. Pakistan’s combined live storage across all reservoirs has fallen from 16.26 MAF in 1976 to about 13.68 MAF, which gives the country roughly 30 days of carryover storage against an international benchmark of 120 days.
How Much Electricity Does Tarbela Dam Generate?
Tarbela Dam has an installed power generation capacity of 4,888 MW, and the powerhouse sits on the right bank fed by the outlet tunnels. That figure is the result of four separate build stages, and it is the number most older articles get wrong.
The original plant reached 3,478 MW from 14 units. Four 175 MW generators on tunnel one entered service in 1977, six more 175 MW units followed on tunnel two between 1982 and 1985, and four 432 MW units were installed on tunnel four in 1992. The Tarbela Fourth Extension added three units of 470 MW each and was commissioned in 2018, taking the total from 3,478 MW to 4,888 MW.
The Tarbela Fifth Extension adds a further 1,530 MW from three units of 510 MW, financed by the World Bank with US$390 million and the Asian Infrastructure Investment Bank with US$300 million. Completion would raise Tarbela’s installed capacity to 6,418 MW. WAPDA’s own statements on the schedule conflict: the project page records completion in May 2026, while a separate WAPDA progress release put first generation in April 2027. Until those units are formally on the grid, 4,888 MW remains the figure of record.
What Role Does Tarbela Dam Play in Pakistan’s Power and Irrigation Supply?
Tarbela Dam is the single largest generating station in the WAPDA hydel system and accounts for roughly half of WAPDA’s installed hydropower capacity. Hydropower from Tarbela is dispatched at the cheapest cost per unit on the national grid, which makes the plant the balancing asset against expensive thermal generation during peak summer demand.
On the water side, Tarbela regulates the Indus for the canal commands downstream at Ghazi Barotha, Jinnah, Chashma and Taunsa. The reservoir is filled during June, July and August when Indus flow peaks, then drawn down through the winter rabi season for wheat. Losing a third of live storage to silt means fewer days of stored water for that release, which is the core argument behind Diamer-Bhasha and the other storage projects now under construction.
Diamer-Bhasha and the Life of Tarbela
Diamer-Bhasha Dam is being built upstream of Tarbela on the Indus, at 272 metres tall with 4,500 MW of installed capacity and 8.1 MAF of gross storage, and completion is scheduled for 2028. Trapping sediment upstream is expected to extend Tarbela’s useful life by about 35 years.
Diamer-Bhasha is funded by the Government of Pakistan with Chinese contracting partners. Claims that the project is financed by the United States are incorrect and appear to originate in older reporting about earlier feasibility funding.
Frequently Asked Questions About Tarbela Dam
When was Tarbela Dam completed?
Tarbela Dam was completed in 1976 after construction began in 1968. The reservoir was first impounded in mid 1974, and the full project including later power stages ran to 1984.
On which river is Tarbela Dam built?
Tarbela Dam is built on the Indus River. The dam sits where the Indus leaves the mountains and enters the plains, about 105 kilometres northwest of Islamabad.
What is the height of Tarbela Dam?
Tarbela Dam is 143 metres, or 470 feet, high above the riverbed. Measured from the deepest foundation, the height is 148 metres or 485 feet. The crest runs 2,743 metres.
In which district is Tarbela Dam located?
Tarbela Dam is located in Haripur District, Khyber Pakhtunkhwa. The reservoir extends into Swabi District upstream, which is why some sources name both districts.
How much electricity does Tarbela Dam produce?
Tarbela Dam has an installed capacity of 4,888 MW after the Fourth Extension was commissioned in 2018. The Fifth Extension will add 1,530 MW, raising the total to 6,418 MW.
Last Thoughts on Tarbela Dam
Tarbela Dam was designed to solve one problem, the loss of the eastern rivers under the Indus Waters Treaty, and it solved that problem for a generation. Fifty years on, the dam’s defining number is no longer its height or its crest length but the volume it has lost. Live storage has fallen from 9.68 MAF at commissioning to somewhere between 5.7 and 6.8 MAF, while installed power capacity has moved the other way, from 3,478 MW to 4,888 MW and toward 6,418 MW with the Fifth Extension.
Those two trends explain the current shape of Pakistani water policy. Generation can be added to an existing structure by drilling new tunnels, so capacity keeps rising. Storage cannot, because silt occupies the space, so it keeps falling. That is the reason Diamer-Bhasha and Mohmand are being built upstream, and the reason Tarbela’s remaining life is measured in decades rather than centuries.
