Given Pakistan's burgeoning population, a shortage of fresh water is likely to be the most serious resource problem the country will face in the years ahead. To compound the problem, global warming is troubling irrigated basins like the Indus, where some 75% of the cropland is irrigated.
New storage reservoirs will also have to be built on the Indus and other rivers to compensate for the reduction in storage capacity of the existing reservoirs--Tarbela and Mangla--due to silting.
There are several reasons to expect water shortages to grow worse. These include further increases in irrigated land for boosting food production to feed a growing population; and growth in the country's urban population, requiring a large increase in water supplies.
Another serious long-term problem is salination. When irrigation water soaks down into the soil, it absorbs mineral salts from the earth, flushing them to the surface. As the water evaporates, these salts dry out on the fields, gradually destroying their fertility. According to one estimate, some 25% of Pakistan's cultivated land has been damaged in this way. Recovering poisoned fields is vastly expensive. The environmental damage done by ill-managed irrigation schemes is a time bomb that threatens to reverse the progress in food production made by past schemes.
Pakistan is currently using half its available run-off, that is, the water that falls on the country and is collected in rivers, lakes and streams, and is drawing half as much again from underground springs and acquifiers.
It has been estimated that by 2025 demand will reach 92% of the entire run-off. So Pakistan faces an awkward choice. Either it must reduce the amount of water used by farmers or it must make huge investments to develop new supplies and build more storage reservoirs. Feeding Pakistan in the years ahead will require such gigantic schemes to be successful--or it will require farmers to use water more efficiently.
At present only one-third of the water used for irrigation actually goes into making plants grow--the rest is wasted. Using water more efficiently would also bring environmental benefits.
Cities and their demands will also grow. In 1951, there was only one urban agglomeration in Pakistan with more than a million people: Karachi. Today, there are more than a dozen, with Karachi alone now at an estimated 14m, Lahore at 8m, and several others at well over a million.
Water supplies are also essential for industrial development. Up to now, few Pakistani cities have found their industrial development circumscribed by water shortages, and that is a considerable achievement. With competing demands for water, however, such shortages are likely to occur with increasing frequency in the years ahead.
Water supply in the lower Indus basin is falling behind agricultural and urban demand, particularly in Karachi where population growth exceeds the physical and institutional capacity of the public water system. Conflict between the provinces on the sharing of Indus basin water obstructs co-operation on lower basin water issues.
Of the 140 million acre feet (maf) of water annually available in Pakistan in a normal year, some 40 maf reach the Indus delta (though it has been much less in recent years). The delta supports important fish and shellfish industries. The lower reaches of the river have several unique riparian species, but are ecologically stressed by upstream impounding of fresh water and sediment.
In recent decades, surface irrigation and drainage problems have stimulated massive groundwater development, involving hundreds of thousands of public and private tube wells. In May 2001, the government said it had directed the Water and Power Development Authority to install another 20,000 tube wells to augment groundwater supplies. But a great many more than 20,000 will be needed to meet the growing demand.
Meanwhile, Wapda has selected several projects for the development of surface water resources for fast-track implementation. The projects include the Rainee Canal, the Kachhi Canal, the Kurram Tangi Dam and the Mirani Dam.
The Rainee Canal project is located on the left bank of the River Indus downstream of Guddu Barrage, from which the main canal for the Thar/Rainee lower canals will off-take.
The project will provide water for the irrigation of about 412,400 acres of agricultural land and water supply to the local population.
Studies for the project are being carried out by Wapda.
A PC-II performa for Rs138m for detailed engineering design and preparation of project tender documents has been approved by the Central Development Working Party (CDWP).
The topography of canal alignment has been completed by Wapda, while 95% of the topographical survey work for the canal-command area assigned to the Army Survey Group has also been completed. Tenders for the earthwork of Stage 1 have been awarded.
For the Kachhi Canal project, a barrage is proposed to be built across the Indus at Mithan Kot, from which a gravity-flow canal will be constructed to irrigate about 513,000 acres of land in the Kachhi plain, along the right bank of the Pat Feeder Canal.
The command area of the project is located in the Dera Bugti, Kohlu and Naseerabad districts of Balochistan.
About 5,000 cubic feet per second (cusecs) of water will be carried through the new canal parallel to the existing Dera Ghazi Khan Canal and Dajal Branch Canal, about 100 miles of which will be in Punjab and 150 miles in Balochistan.
The project also includes the construction of a new irrigation distribution system for fallow but fertile land in Balochistan.
Work is in progress to carry out a topographic survey of the command area, which has been assigned to the Survey of Pakistan. A PC-II performa for Rs170m for detailed engineering design and preparation of project tender documents has been approved by the CDWP.
The Kurram Tangi Dam project is located on the Kurram River in the North Waziristan Agency, in the Federally Administered Tribal Areas of the NWFP. The dam site is 22km upstream of the Kurram Garahi head works and 32km north of Bannu.
The scheme will create a storage dam for conserving a large amount of floodwater in the Kurram and Kaitu rivers, which will add to the storage in the existing irrigation area of 278,000 acres. The stored water will also be used to irrigate about 84,500 acres of new areas, under perennial irrigation. The project will also generate hydro electricity.
A PC-II performa for Rs125m for the preparation of a feasibility study, detailed engineering design and project tender documents has been approved by the CDWP.
The government has also allocated Rs12.8bn for construction of the dam.
The Mirani Dam project is proposed to be constructed on the Dasht River about 48km west of Turbat in the Mekran region of Balochistan. The project has been included in the list of fast-track projects instead of Hingol Dam on the Hingol River, near the Coast Guard's Aghor Camp in Bela district.
The objectives of the Mirani Dam project are to store 302,000 acre-feet of water for flood control and to irrigate 32,000 acres of land on the right and left banks of the Dasht River. The scheme will also supply water to the new port being built at Gawadar.
Project planning for the scheme has been completed. A PC-II performa for detailed engineering design has been approved by the CDWP.
The Executive Committee of the National Economic Council has approved a PC-I performa allocation of Rs5.811bn towards the cost of building the dam. An Environmental Impact Assessment study for the project is under preparation. Wapda's Planning and Investigation Organisation is currently carrying out field surveys, site investigations and other planning activities relating to the project.