Mangla Dam

The Manga Dam in Pakistan is the twelfth largest dam in the world. It was built in 1967.

Historic development

In April 1948, India diverted the flow of the Ravi, Sutlej and Beas rivers, an act which threatened irrigated cultivation in Pakistan. That same year, in an effort to mitigate the consequences of possible interference by India with the supplies of the canals feeding from those rivers, Pakistan embarked on a program of link canal construction to enable the transfer of water between rivers.

Until 1967, the entire irrigation system of Pakistan was fully dependent on unregulated flows of the Indus and its major tributaries. The agricultural yield was very low for a number of reasons, the most important being a lack of water during critical growing periods. This problem stemmed from the seasonal variations in the river flow and the absence of storage reservoirs to conserve the vast amounts of surplus water during periods of high river discharge.

Mangla Dam was the first development project undertaken to reduce the shortcoming and strengthen the irrigation system.

The Mangla Dam project

Mangla Dam is the twelfth largest dam in the world. It was constructed in 1967 across the River Jhelum, about 60 miles southeast of the federal capital, Islamabad. The main structures of the dam include 4 embankment dams, 2 spillways, 5 power-cum-irrigation tunnels and a power station.

The main dam is 10,300 feet long and 454 feet high (above core trench) with a reservoir of 97.7 square miles. Since its first impounding in 1967, sedimentation has occurred to the extent of 1.13 MAF, and the present gross storage capacity has declined to 4.75 MAF from the actual design of 5.88 MAF. The live capacity has declined to 4.58 MAF from 5.34 MAF. This implies a reduction of 19.22% in the capacity of the dam.

The project was designed primarily to increase the amount of water that could be used for irrigation from the flow of the River Jhelum and its tributaries. Its secondary function was to generate electrical power from the irrigation releases at the artificial head of the reservoir. The project was not designed as a flood control structure, although some benefit in this respect also arises from its use for irrigation and water supply.