The dreaded scourge of water scarcity has finally hit Pakistan. This is nothing unexpected. Given, the manner in which we have misused our natural resources, this catastrophic occurrence was bound to overwhelm us.
At the time of independence, 5,000 cubic meters of water was available for each Pakistani, which has now reduced to 1,000 cubic meters because of explosive population growth. Water is one resource that cannot be generated, it can only be preserved. Acumen dictates that we conserve each and every drop of available water because if this invaluable commodity is not prudently preserved and consumed, the survival of the human race as a whole is jeopardised. It seems increasingly likely that future wars will be waged over the possession and control of dwindling water supply. The only realistic approach to conservation is the construction of a viable dam infrastructure. Dams have been built in some form or the other for at least 5,000 years and, their functions have evolved with the needs of the society. Most likely, the earliest dams were built to store water for domestic and agricultural water needs. With the onset of industrial era, hydropower became the major incentive to built dams. It has also been noted that all reservoirs are destined to die a natural death. This is due to the steady loss of their storage capacity because of sedimentation.
Assuming an average life of hundred years for an individual dam, the world is losing about 41 cubic kilometers of storage capacity each year. Although we cannot completely halt this process, with our knowledge and effort we can delay this process and extend their life. So far, few methods are available for prolonging the storage capacity and life of reservoirs. In this case, the most careful and resource preservation methods encompass the construction of series of dams on the river so as to trap sediment inflows in the upstream reservoirs and store relatively sediment free water in the lower reservoirs. It was estimated that Kalabagh’s reservoir life with Tarbela upstream and a conjunctive operation could be extended to 100 years. Other operational methods include sediment sluicing along with water flows through the dam outlets and flushing of accumulated sediment through reservoir regulation methods, though these methods involve tradeoff between stored water and reservoir capacity because stored water shall have to pass through the dam unobstructed.
It is important for us to consider the implications posed by the fact that we have become a water scarce country despite have such rich water sources. Soon after the creation of Pakistan, the country was faced with a number of serious problems including that of electricity and water shortages. The control of three out of five Punjab Rivers had gone to India, which disrupted water supply to canals feeding the eastern districts of United Punjab and the Bahawalpur State. The unilateral action of the Indian Government ruined our cultivated land which was soon rendered barren. This affected the economy of the newly created country very badly and the danger of famine cast a long shadow. Therefore, Pakistan had to mobilise her own resources. Casting an eye on the problem, it is fairly easy to surmise that the absence of additional storage has forced us to burden Tarbela adversely by inflicting undue pressure on the system which has caused large sediment deposits within the reservoir towards the dam well before it was expected. The Kalabagh controversy began roughly 15 years ago and during this period, we did nothing but concentrate on rhetoric in favour or against Kalabagh. Although it was known that consensus on construction of a major new reservoir would take some time to forge and that preparation of its feasibility, design and then construction would take not less than 15 years. Furthermore, the case for Kalabagh was strengthened by the fact that its designs are prepared and even tender documents are ready. WAPDA was established to develop the water and power resources of the country being structured as a multi-disciplinary organisation granted great autonomy to further its goals. It was at its zenith when it completed, successfully and in record time, the gigantic Indus Basin Project. Sadly after the Indus Basin Project, no major construction project with the exception of SCARP was undertaken by WAPDA but it continued its effective and productive role of water development through research and studies.
Various inspections of Tarbela Dam by experts recommended different solutions to tackle the sedimentation problems of the reservoir. For testing and researching these solutions, it was proposed that a physical model studies laboratory be established at Tarbela site on a priority basis . This laboratory would not only undertake a comprehensive research and study to find solutions to Tarbela problems but would also cater for future needs of other projects on the Indus River and its stream.
WAPDA has now come up with its ‘Vision 2025”. However given the limited level of in-house knowledge and expertise can it even initiate such a utopian programme? This project is going to be far more problematic than Tarbela. No local firm is capable of undertaking its investigation without active collaboration of foreign experts. Had we sustained research and study efforts and inculcated the requisite level of expertise within WAPDA, we would have achieved a level of knowledge whereby our dependence on foreign expertise would have considerably
lessened.
