Back

SKARDU DAM (Proposed)

KEY FACTS

LOCATION

The Skardu dam site is located at a latitude of 350 28' N and longitude of 750 24'E, some 25 km downstream of the confluence of the Indus with the Shigar River near the town of Skardu. Road access to the site is from the Gilgit-Skardu highway on the north towards the right abutment of the proposed dam. Access to left abutment is via the Ayub Bridge, which crosses the river about 5 km upstream of the dam site. The nearest airstrip is located 14 km downstream at Skardu.

ALTERNATIVE DAMSITES

An alternative dam axis was considered approximately 1 km upstream. The site is similar to the one chosen, with talus on the right abutment. However on the south abutment, the rock outcrop appeared to be more weathered and hence the other option was preferred.

GEOLOGY OF THE REGION

The left abutment is a rock cliff about 200 metres high, dropping nearly vertically to the river. There is some talus deposited on the upper slopes. According to estimates, the granular deposits are 100 metres thick on the right bank, extending about 200 m away from the river at a gentle slope. The rock is a massive diorite with pegmatic texture and is suitable for tunneling and quarrying. Granular material is also available locally.

The area is seismically active, although very little published data is available. The site is close to the tectonically active Indus Suture Line and the possibility of high magnitude seismic events must be taken into account.

THE SKARDU DAM PROJECT

The dam axis is located at the end of a mild bend in the river. The north abutment has heavy overburden cover whereas the main feature of the left abutment is a solid and steep rock outcrop.

River diversion during dam construction will be through 3 concrete-lined tunnels of 14 metres internal diameter, cutting through the bend in the south abutment. The spillway will be located on the left abutment resulting in substantial volumes of excavation, due to great depth of talus on the right abutment. The spillway will have a 600 metre long approach channel leading to the control structure containing 6 square gates - 20 x 20 metres each. A 150 metre wide concrete-lined chute will convey water to the flip bucket and plunge pool.

A rockfill dam with impervious core will be built due to the easy availability of impervious material in the Skardu plain. The dam will be 230 metres high above the riverbed and the project will store water only for irrigation purposes. Water releases will be made through a vertical intake structure leading to diversion tunnels. Releases will be controlled by hollow cone valves located at the downstream ends of steel pipes, which will be embedded in concrete plugs.

CURRENT STATUS

Presently, the government is not considering the Skardu Dam Project as high in priority. Further studies are required to update the earlier ones and allocation of funds for construction is needed.

The cost estimated in PC-1 was US$ 3.829 million. However, because the project will not produce any hydel energy, the government has not allocated any funds for Skardu Dam project in the Ten Year Perspective Plan. The government is looking to the donor agencies for a grant-cum-aid arrangement for the project, if possible.

REFERENCES

1. Montreal Engineering Company, "Hydroelectric Inventory Ranking and Feasibility Studies for Pakistan - Phase A" WAPDA / CIDA Project, Volume 2 of 3, November 1984.
2. Pakistan Water and Power Development Authority, "Annual Report 1999-2000", 2001.
3. Pakistan Water and Power Development Authority, "Monthly Progress Report for February 2002", Hydroelectric Planning Organization, March 2002.