Soan Dam
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| Soan Dam | |
|---|---|
| Location | Potohar region, Pakistan |
| Purpose | Water storage, Power generation |
| Status | Proposed |
| Construction cost | $7 billion |
| Owner | Government of Pakistan |
| Dam and spillways | |
| Impounds | Soan River |
| Dam volume | 38 million acre-feet (47 km3) |
| Power Station | |
| Installed capacity | 5,240 MW |
Soan Dam is a proposed dam on the Soan River in the Potohar region of Pakistan. The dam has a proposed storage capacity of 38 million acre-feet (47 km3) and a power generation capacity of 5,240 megawatts (MW). The dam is being proposed to address the water scarcity, Flood control/harvesting, energy crisis and Economic recovery of Pakistan.[1]
The Soan River is a perennial river that originates in the Murree Hills and flows through the Potohar region.[2][3] Soan gorge has enormous storage potential (100+MAF) with multiple suitable dam sites between Rawalpindi and Soan-Indus confluence. An earth fill dam near Dhok Pathan is proposed to store Indus water diverted from Tarbela's left bank Siran Pocket near Haripur.[4]
Site was initially studied by Dam Investigation Circle in 1955.[5] During 1960's, World bank proposed 8.5 MAF storage design which was ignored for next three decades and finally downgraded to 1 MAF design in 2002. Unfortunately, storage capacity was never measured because legacy techniques needed a lot of time and resources. Even World bank created an estimated map for 8.5 MAF proposal which was almost same for 5 times larger capacity. See attached map for comparison.
Design
Storage capacity can be decided per requirement. at an optimal retention level of 405 MASL, 38 MAF is achieved. Tarbela's dead level in 2024 is around 427 MASL (and increasing). diverting 30 to 45 MAF of water near dead level will resume the sediment transport through Tarbela to be flushed back to Indus via Haro river.
At lowest level on 427 MASL, leaving another 10 m for high flow canal, Dhok Pathan offers more than 45 MAF storage capacity.
Soan Reservoir is a side valley storage type, located at a convenient elevation to serve multiple roles.
- It allows a natural head for a 100 km long feeder channel for filling the reservoir during flood days. This link channel can flush sediment from Tarbela and release it back into Indus below Barotha exit.
- During extreme floods, It can divert Tarbela upstream flow indefinitely to ease Kabul and Swat floods.
- It can allocate storage for year around environmental flow in Indus river. This will improve water quality, wildlife and allow economical river transportation.
- Environmental flow will resume sediment transport to pre-Tarbela levels.
- Its drawdown level is 160+ feet higher than crest of Kalabagh dam. Soan Dam's elevation can command additional 32 million acres in all four provinces for high efficiency precision irrigation.
- Every inundated acre will irrigate 140 acres of new land.
- Soan storage can split and absorb extreme floods in Indus basin.
- It can balance flow with Right and left bank catchments and tributaries of Indus river.
- Diverted water has average energy of 30,000 GWH between Tarbela and Kalabagh, which translates into an average output of 4400 MW, mostly in ROR mode.
- Soan site is located 40 km east of Kalabagh site. It doesn't effect the Kalabagh design, but Kalabagh may never be needed once Soan is built.
- Cost wise, it offers ten times cheaper storage than alternative proposals.
- It has design conflict with current design of expensive yet far inferior project of Akhori dam (6 MAF), whose raised reservoir inundates axis of Soan link canal.