Mangla dam is the first-ever mega multipurpose project in Pakistan comprising of water storage & four power generating units of 100 MW each completed in 1967. Like Tarbela dam, Mangla dam is also brain-child of replacement works of Indus Water Basin Treaty signed on 19th September 1960 at Karachi by Indian Prime minister Pandat Johar Lal Nehru and President of Pakistan Field Marshal Muhammad Ayub Khan. Subsequent to completion of its up-raising project, Mangla dam has become the biggest water reservoir of Pakistan, surpassing Tarbela which has a live storage capacity of 6.45 MAF.
Construction work on Mangla dam commenced on March 1963 and was completed in just 4 years and three months in June 1967 at the cost of $ 434.505 million with water storage capacity of 5.88 MAF and power generation capacity of 400 MW with units 1-2-3 & 4 each of 100 MW. Its generation capacity was enhanced in 1974 by commissioning two more units i.e. 4 and 5 each of 100 MW. In 1981, the power generation capacity was further augmented by installing units 7 and 8 each of 100 MW. In view of the daily surging demand of electricity, units 9 and 10 were erected in the year 1993-1994 each of 100 MW. The cumulative production from all the ten operating units is 1000 MW.
With the passage of time the storage capacity came down to 4.67 MAF due to the natural phenomenon of silting/sedimentation. To increase its live storage capacity and maximize the hydropower potential of river Jhelum, Mangla dam up-raising project was initiated in July 2004 at a cost of Rs. 96.853 billion. The project was completed in December 2009 with the raised height of dam equal to 30 feet a d maximum permissible water level of 1242 feet (above mean sea level). Storage capacity of the raised Mangla dam is 7.48 MAF. Net increase in storage capacity is 7.48 – 4.67 = 2.81 MAF (i.e. one foot of water standing over 2.81 million acres of land). Whereas the additional 2.81 MAF of water will irrigate 1.31 million acres of land and generate 644 million more energy units per year, the raised Mangla dam has played a significant role in mitigating the flood miseries by holding in its reservoir a huge quantum of water. Had the Mangla dam not been raised to the height of 30 feet, the devastation in terms of loss of human life and livestock and damages to corps and property would have been more than what was experienced during the raging floods of September 2014.
The impounding benefits being harnessed from the raised Mangla dam have, as a matter of fact, given an alarming call to the incumbent government to wake up from slumber and construct the long procrastinated, much talked about, and yet undecided Kalabagh dam to rid the country of darkness.
Generally the hydroelectric generators have a useful life of 35 years but generators at Mangla are almost 50 years old and still operating efficiently and effectively. Keeping in view the growing age of the hydropower generating equipment, a plan has been devised to systematically refurbish the generators in next five years. As such the Mangla refurbishment project is in place to increase the generation capacity of Mangla hydel power station to 1310 MW from existing 1000 MW. The project, which is being implemented by WAPDA, is to be completed phase-wise on a fast-track basis. Power generation units will be refurbished by closing one tunnel (two generating units at a time). Units 5 and 6 will be refurbished by the year 2018 and Units 1 to 4 by the year 2020. Mangla refurbishment project shall stand completed by the year 2022 when all the ten units are refurbished. The latest technology will be used to optimize the generation capacity of Mangla hydel power station. With the use of this technology, the volumetric flow rate of water for generating 1310 MW of electricity shall be the same as required for generating 1000 MW of electricity.
In order to effectively control soil erosion and reduce sediment rates, a watershed management programme has been continuously implemented by WAPDA since 1960 in Mangla reservoir’s catchment area covering 5710 square miles in AJ&K and Pakistan. During the last 55 years as much as 133 million trees have been planted in addition to the construction of stone and earthen structures measuring 122 million cubic feet in the form of check dams and retaining walls, construction of 4000 engineering structures of stone masonry, improving 8400 acres of cultivated land and imparting training to farmers. Resultantly the sediment load has been reduced to 2774 acres feet/annum from 42,000 acre feet/annum as estimated by consultants of Mangla dam in the design of project in late 50s and 60s.
In addition to planting 1.325 million saplings spread over and area of 1960 acres, WAPDA is also aimed at constructing soil conservation structures equivalent to 3.774 million cubic feet and 183 engineering structures during the current fiscal year 2015-2016 under the programme of watershed management. All these well-planned and concerted efforts shall go a long way towards managing the sediments and hence the enhancement of reservoir’s life by another 100 years from 100 to 110 years as earlier envisaged by the consultants in the design of Mangla dam project.
It will not be out of place to mention that the people of Mirpur in Azad Kashmir have offered sacrifices twice during 1960s and again during the upraising project of Mangla dam. The graves of their ancestors and near and dear ones stand submerged in the deep waters Mangla lake. The problems of Manlga dam affectees are yet to be addressed by the Government of Pakistan.