Pakistan: Major Dams Hit Dead Storage Level

25 July 2018 Christopher Crellin, Research Assistant, Global Food and Water Crises Research Programme


Pakistan has hit yet another critical moment in its struggle for water security. It continues to suffer from climate change-induced drought, bouts of low frequency, high magnitude rainfall that causes floods, combined with the increased demand for water that is linked to rapid population growth and urbanisation.

The Tarbela and Mangla Dams in the Indus Basin have reached dead level, meaning that the water level in the dam is too low for it to operate. Reports from the United Nations Development Programme and the Pakistan Council of Research in Water Resources, suggest that the country will reach absolute water scarcity by 2025. If Pakistan does reach absolute water scarcity, the availability of physical water resources will not adequately supply demand. According to the water stress index, absolute water scarcity is reached if the amount of renewable water falls below 500 cubic metres per person per year.

The Pakistan Metrological Department and the Indus River System Authority have linked the dwindling water levels of the Tarbela and Mangla dams to climate change influences. Insufficient rainfall in catchment areas and low temperatures in the western Himalayas (which has reduced snow melt) have significantly reduced the flow of water from the Indus and Jhelum Rivers into these dams. The inflows into the dams are at rates equal to their outflow. If adverse climatic factors, such as erratic rainfall, extended periods of drought and reduced snow melt, are maintained or worsen, it is difficult to forecast when the dams will recover from dead level.


Diminishing water levels in the dams are likely to have an adverse effect on agricultural production, meaning that Punjab and Sindh provinces are unlikely to receive enough water to meet their irrigation requirements. Constricting agriculture because of diminishing water supplies could have detrimental effects on long-term food security and disruptive economic impacts for Pakistan.

Agriculture generates approximately 19.5% of Pakistan’s gross domestic product and half of its employed labour force works in the industry, making it the largest economic sector in the country.  A reduction in water supplies will inevitably restrict agricultural production and constrict Pakistan’s economy. Lower cotton production levels, for example, will affect Pakistani manufacturing industries by lowering production levels and increasing costs. Lower production levels in the agricultural and manufacturing sectors will slow Pakistan’s pace of development and may lead to greater societal strain, as workers attempt to find alternative sources of income.

A  Pakistan Business Council report states that Pakistan’s agricultural sector is severely underperforming, which could be partly linked to the current water crisis. Pakistan produces 3.1 tonnes of wheat per hectare, compared to 8.1 tonnes in France; and 2.5 tonnes of cotton, compared to 4.8 tonnes in China. The water crisis and underperforming crop yields will critically affect Pakistani food security. A decline in domestic agricultural production will increase food prices and lower workers’ incomes, straining families’ ability to access food. On a larger scale, if agricultural production continues to decline, exports will also decline and the country will increase its reliance on food imports.

The supply of electricity is also of concern, as the dams reach dead level. The Tarbela dam has a generation capacity of 4,888 megawatts (MW) and provides a total 3.84 gigawatt hours of electricity to Pakistan’s national grid each year. The Mangla dam has a generation capacity of 1,310MW.

Before the Tarbela 4th Extension Hydropower Project, its most recent upgrade, the Tarbela dam produced 16 per cent of Pakistan’s electricity. The upgrade increased the generation capacity by 40 per cent. It adds diversification to the Pakistani electricity supply and decreases its dependence on fuel imports.

As the Tarbela dam is now at dead level, however, it will become incapable of generating electricity as water outflow from the dam ceases and siltation levels increase. Subsequently, Pakistan’s power grid could be put under severe stress, as electricity supply decreases but demand remains constant or even increases. Pakistan already experiences frequent power failures and blackouts, as rapid increases in demand have not been met, which often leads to protests and bouts of violence. In July, parts of Punjab and Khyber Pakhtunkhwa experienced major blackouts. The national grid had a 4,000 MW shortfall as the Tarbela, Mangla and Ghazi Barotha power plants tripped. The blackouts caused havoc as major public infrastructure, including hospitals, government offices, schools and airports, were left without power.

Pakistan is heading into the south-west monsoon season. In June, the Pakistan Meteorological Department forecast normal to above normal rainfall during the first half of the pre-monsoon season, with the monsoon season itself starting in July. To increase long-term water storage capacity and improve water resilience, the Pakistani Supreme Court ordered the immediate construction of two more dams.

Monsoon rains could replenish the water levels in Pakistani dams. In the long-term, however, there is a need for greater levels of water management, so that absolute water scarcity is avoided. Sound governance frameworks are necessary to support agricultural and manufacturing production. Tarbela and Mangla dams are vital sources of water and electricity and, unless their water levels are replenished by the south-west monsoon, Pakistan is likely to experience a decline in its agricultural and manufacturing output.

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