PAKISTAN'S FAST DEPLETING FRESH WATER
DR. S. M. ALAM
Mar 29 - Apr 4, 2010
Allah has created every moving (living) creature from water (Surah 24, An-Nur, Ayet 45). Fresh water is only 0.008 % of the water on earth.
A shortage of fresh water is probably going to be the most serious resource problem the world will face after a few years from now. Unlike food, the problem of water is not because of shortage, but because of uneven distribution. Three-quarters of the fresh water on the planet is held in the polar icecaps and glaciers and so it is unavailable for use. Where water is plentiful, people are less in numbers, and vice versa.
The most water-rich country in terms of the run-off from rainfall to population is Iceland in Europe, having 500,000 cubic meters per person per year. The most water poor is Egypt in Africa with just 0.02 cubic meter per person per annum.
A country is classified as water-stressed when annual supply dips below 1,700 cubic meters per person, and is said to face water scarcity below the 1,000 cubic metres per person mark.
Per capita water supply in Pakistan stood at a 5,500 cubic metres in 1951. It has since plummeted by almost 80 per cent, and according to an estimate, could drop to as little as 700 cubic metres per capita by 2020.
Many parts of the world are confronted with water scarcity, for both irrigation and human needs. Some 70 per cent of the water is used for irrigation. Since 1950, the amount of irrigated land has tripled, and one-third of the world's food is grown on it. Without that increase, the world might now be starving.
Controversies over distribution of river water and construction of reservoirs, dams, barrages and link canals are very common among the various countries of the world. Providing water for irrigation and for cities requires damns on rivers, flooding more valleys, carrying out more giant water engineering schemes. Such projects are often hugely expensive and not only in economic terms has it cost otherwise also. Large dams frequently involve massive changes in the use of land. Dams also produce water for irrigation and for generating hydroelectricity, controlling floods, producing fish and even providing recreational facilities but serious attempts to measure the benefits from dams suggest that the gains are often smaller than the costs.
The disputes over the distribution of river waters are very common in the human society. Water resources often cross national boundaries, making it very easy for one country to 'steal' the water that should be delivered to another. It is said that future conflicts will be rooted in disputes over water. No one can predict which of several points of tension in the world will result in armed conflict, but it is easy to list some potentials. They include threats to dam the upper Blue and White Nile; the diversion of water from the Sea of Galilee into Israel's National Water Carriers, the Gabcikovo dam on the Danube in Slovakia; the damming of the upper reaches of the Tigris and Euphrates by Turkey and the Euphrates by Syria, distribution of water of river Ganges between Bangladesh and India, construction of dam on river Kavari between two southern provinces of India. The distribution of water's shares of Indus has been a source of conflict between India and Pakistan, but in 1959 an agreement was reached whereby the water would be shared. Tensions related to water-sharing are nothing new in the subcontinent but they received fresh impetus with the construction of Baglihar Dam in Indian-held Kashmir. The potential for conflict runs deep and is not limited to states taking on other states. Within nations, downstream users may accuse upper riparian of stealing their water and thus their rights and livelihoods. This has long been a simmering issue in Pakistan, one that has stoked the fires of nationalism and increased the trust deficit between provinces.
Water-related issues can also infight village against village, clan against clan and farmer against farmer. From the international stage to rivalry between individuals, the potential for conflict exists at every level and demand for water has so dramatically outstripped supply for a number of reasons. These include an ever-burgeoning population, the absence of integrated water management, irrational use and lack of awareness of the need to conserve. Wasteful farming techniques, leakages in the irrigation network, climate change and the over-exploitation or pollution of natural aquifers and other water bodies also rank among the major culprits.
The arid and semi-arid regions of the world have to depend on river water sources for their agriculture i.e. mainly on artificial canal irrigation system.
The source of main water in Pakistan is canal irrigation system. The Indus valley, comprising the planes of Punjab and Sindh is mainly dependent on the water of river Indus and its tributaries, as the area is mostly arid on the basis of annual precipitation. The river Indus is the life line for Pakistan's agriculture. The Indus river rises from a lake named Manasarowar in southwestern Tibet at an altitude of 16,000 ft or 4,900 m and flows in a north westerly direction along the slopes of the Himalayas, travelling a distance of about 1500 miles and crossing at north-west Jammu and Kashmir from the southwest. In west Kashmir it flows through a 13,000 ft deep channel. The river Indus is a great trans-Himalayan river of south Asia and one of the longest rivers of the world having a length of 18,00 miles (2,900 km).The glaciers of Siachin (75 km), Baltro (62 km), Hispar (53km), Biafo (50km), Shyok, Shingar, Hunza, Gilgit, Astor, and other streams with 30 tributaries constitute a surface area of 1220 sq kms (471 sq miles ) carrying snowmelt waters to the Indus from the main Hamalayan range, the Karakoram range, the Nanga Parbat, the Kohistan ranges etc mostly in summer season.
The river crosses the western Kashmir border and then turns south and southwest to enter Pakistan. In Pakistan, it emerges from the mountain highlands flows as a rapid stream between the Swat and Hunza regions and proceeds onwards through North West Frontier region and crosses the salt range to enter semi-arid Punjab plains where it is joined by the Panjnad (near Mithankot). The Indus receives its most notable tributaries from the Punjab to the eastern sides, including Jhelum, Chenab, Ravi, and Sutlaj rivers. After receiving the waters of the Punjab rivers shifting to the south-west, the Indus becomes much wider and enters into the Sindh region near Kashmoor and then flows to a slow speed, depositing large quantities of silt along its course. Indus begins its deltaic stage (3,000 sqm) and breaks into distributaries that reach the Arabian sea at various points southeast of Karachi.
Water resources are the most critical factor of production in Pakistan's agriculture. To increase agricultural production, land is not a limiting factor as there is more cultivable land available that can ever be properly irrigated. It is a universal solvent and cleanser. It has a very economic value, which is at a constant rise with population.
Pakistan is arid to semi-arid country, located between the longitude 61∞ east to 76∞ east and between latitude 23∞ north to 37∞ north. Total area of Pakistan is 79.61 million hectares. Population of the country is about 180 million and nearly 75 per cent of it lives in the rural areas. Agriculture is the main stay of Pakistan's economy, contributing 35 per cent to the gross domestic product and providing 60 per cent of the labor force. Moreover, nearly 60 per cent of the total export of the country originates from agriculture. Total annual cropped is about 22.72 million hectares. Out of which, 15.3 million hectares are irrigated areas, about 75 per cent (11.4 mha) is irrigated through canals, l9 per cent (2.9 mha) through tube wells, 2 per cent (0.3 mha) through wells and remaining 4 per cent (0.4 mha) through tanks and other sources. Major crops grown are wheat, rice, cotton, maize and sugarcane. Production of three important crops namely rice, cotton and sugarcane as well as 90 per cent of wheat and most of maize is virtually confined to irrigated areas. The climate of the country is favorable for two crop seasons.
In the country, the total water supplies available to agriculture come from different sources including rainfall, surface water from the Indus river and its tributaries, the ground water, and also from sewage water and seawater.
The mean annual rainfall varies from less than 100 mm in Sindh to more than 1000 mm in the foot-hills and northern mountains with an average of about 400 mm. About 60 per cent of this rain comes during the monsoon season (July through September). Much of the summer rains are not available for crop production due to rapid run-off because of torrential showers. At other occasions, rain may be so light that the precipitation evaporates before the water can penetrate into the root zone. Rainfall alone is inadequate to sustain more than a very low level of agricultural production in the semi-arid conditions which prevail over most of Pakistan. Ground water is the second major source for irrigation. The seepage through rainfall, rivers and vast canal network has created a large and readily manageable acquirer underlying the Indus basin. The total recharge to the groundwater system of the Indus Basin has been estimated at 56 MAF per annum. Presently, the ground water is being developed in canal commands of Indus plain for the purpose of irrigation on the large scale and is of the order of 48 MAF per annum.
There is a huge source of highly saline seawater along the 1,050 km coast of Pakistan along the Arabian sea but it cannot be used either for drinking or irrigation unless desalinized. Some palm and coconut trees can be grown in coastal belt using saline water. With the extension of big cities and towns the quality of sewage water is increasing considerably. It is mostly used for the production of high value crops like vegetables, fodder, oil palm, coconut etc. in the vicinity of cities and towns. However, there is a common belief that the vegetables raised from sewage water are not safe for consumption from hygienic point of view.
Irrigation system of Pakistan was developed from the Indus water in 1850 and is now the largest integrated irrigation system in the world. The flow of Indus river system is the prime source of surface water resources of the country. It covers gross area of 16 million hectares of which 88 per cent is cultivable. It has 48 principle canals, emerging out of 20 river diversion structures. Many of the canals are even large by world standard; 15 of them having capacities of over 280 cubic meter per second. The cumulative operating capacity of these canals is 7323 cubic meters per second. These canals traverse about 61,000 kilometers to command the 16 million hectares of culturable area through 90000 watercourses and filled channels numbering 1,07,000. Each watercourse serves about 160 hectares of land on the average. In addition, there are 23 barrages, 45 main canals, 12 huge inter river link canals transferring bulk water supplies from the western rivers to the eastern rivers.
Presently, Pakistan irrigation system encompasses two major dams: Mangla and Terbela. The main technical features of Mangla dam is that it is the world's third largest earth filled dam, built on river Jhelum with height-380 ft above river bed, length 10300 ft, gross water storage capacity of 5.88 MAF, live storage capacity of 538 MAF, spillway capacity of 870,000 cusecs, emergency spillway capacity of 230,000 cusecs, and lake area of l00sq miles. The main feature of Terbela dam is that it is the world largest earth and rock-filled dam on one of the world's most important river the Indus with height of 485ft. above river bed, length of 9000 ft, gross storage capacity of 11.3 MAF, live storage capacity of 9.4 MAF, service spillway capacity of 6,50000 cusecs, auxiliary spillway capacity of 840,000 cusecs, and lake area of 100 sq miles. The Terbela dam is known as the best hydropower station in Pakistan having a capacity of generating 3,478 MW of electricity.
The Chashma reservoir helps in the irrigation of millions of hectares of agricultural lands. In addition to the grand canal system, there are about 605,000 private tube wells with average capacity of 30 liters per second and about l5000 public tube wells with capacity of 60 to 120 liters per second. At present these tube wells pump about 41 billion cubic meters water and provide 30 per cent of the total irrigation water to exclusively more than two million hectares in addition to supplementing some canal fed areas. Total available water resources of the country from the rivers as well as ground water come to 160 million acre feet (136 MAF from rivers i.e. 94 MAF from Indus; 20 MAF from Jhelum and 26 MAF from Chenab; and 24 MAF from ground water sources). Out of this, 101.4 MAF reaches at the modules or the starting points of the watercourses, after deducting losses of the system, i.e. seepage from the canal and distributaries, 35 MAF water is wasted into the sea during flood season every year. About 15 per cent additional water is lost due to improper irrigation applications, which in absolute terms is 8.4 MAF.
Pakistan needs 170 million acre feet of additional water in future to meet irrigation and other requirements of the people. This is not possible unless new storage dams are built. India is planning to build Salal dam on the Chenab river and diverting the Indus river water from the Wooler lake in occupied Kashmir.
To overcome water shortage crisis, the solution lies in the proper water management at watershed, reservoirs, conveyance system i.e. at canals and distributaries level and watercourses and farm application leveling of open channels and use of pipes to transport water for reducing seepage losses. There is a need to prepare cemented water beds at the bottom of the base. Building of more dams in the country is also good solution to solve the problem of water shortage. Million of acre feet of valuable water which is flowing into the sea every year could be stored for irrigation at a time when it is needed the most.
Kalabagh Dam should be built for the betterment of the country and to prevent acute water shortage in future. Officials of each province should be consulted for equal share and distribution of water. The Kalabagh dam project should be supplemented with supportive irrigation projects in Balochistan, Sindh, Cholistan and the NWFP to take the benefits of additional water available from the Kalabagh reservoirs to take their respective areas. The politicians have to use their wisdom rather than emotion to come to a decision in the country's national interest.
The crisis of water shortage for irrigation can be overcome through proper water management practices. Some of the points to be kept in mind are: evaluation of available water resources, development and improvement of existing irrigation systems, judicious and efficient use of available irrigation water, control of evaporation from water surface in reservoirs and canals, evaluation of water requirement of various crops, knowledge of modern techniques of crop and water management, active participation of farmers in water users association, and better understanding between government and farmers community. The tail end farmers on a watercourse do not receive their due share. The inconsistency of water supply to the tail ends of canals and watercourses due to the presence of influential people at the head of canals, seriously affects the morale and production of the tail end farmers. Massive education for proper use of water along with modern techniques of land leveling can save substantial quantum of water. To obtain the best results, effective co-ordinations between the departments of irrigation and agriculture is the cardinal point for success.