CONSTRUCTION OF NEW DAMS UNAVOIDABLE, BUT JUDICIOUS WATER USE MORE VITAL
Many analysts are of the view that adding new storage facility will be of no consequence unless water distribution system is improved.
By SHABBIR H. KAZMI
Feb 06 - 12, 2006
Now oil prices often hit the headlines and it is also being said that geopolitical changes are aimed at achieving control on energy resources. However, many experts say that the third world war will be for getting control of water supplies. Water is the source of life on earth and essential for people, agriculture and industries. Unlike many other resources it follows a closed cycle - it is 'recycled' by nature through various physical states. Usable freshwater comes from rain and snow. It flows as streams and rivers, and is called surface water. It percolates through the soil to be stored underground as ground water. While the latter is dependent on above-ground water supplies and is a secondary source of water, surface water has no such limitations. Agriculture may be the largest user of water, human beings and industries also use substantial quantity of this precious resource.
The area now part of Pakistan had been named Punj-ab (five waters) because of five rivers flowing in the area and irrigating lands, the main source of income for thousands of people. Though the number has virtually reduced to three after sixties, mighty Indus has been providing enough water to keep lands lush green. However, it is often felt that during certain months a large part of lands come under flood water and in certain months there is not enough water for irrigation. It is only because the country does not have required water storage facilities. When water level rises in rivers, due to snow melting and rainfall, spillover causes flood and the fast moving water ultimately falls into Arabia Sea. Therefore, it is necessary that water reservoirs should be built in the country to achieve twin objects of ensuring availability of irrigation water throughout the year and generating low cost electricity.
After independence the issue of water sharing between India and Pakistan aroused. While negotiations between Pakistan and India to resolve the Indus water dispute were in progress (1947-60), Pakistan undertook construction of three inter-river link canals to ensure a continuous supply of water. These were BRBD Link (1952), Balloki-Suleimanki Link (1954), and Marala-Ravi Link (1956). These link canals ultimately became part of the Indus Basin Replacement Plan. Pakistan also constructed three barrages on the Indus River to convert the existing inundation canals into controlled ones to ensure a more reliable water supply. These barrages were Kotri (1955), Taunsa (1958), and Gudu (1962) with a total canal command area of about 8 million acres. The present irrigation system consists of the three storage reservoirs - Mangla, Chashma and Tarbela - which became operational in 1967, 1971 and 1976, respectively; 16 barrages, 12 inter-river link canals, 2 siphons and 43 main canals. The total length of the main and link canals, branches, distributaries, etc. is about 35,000 miles.
It may be true that Pakistan has world's largest man-made irrigation system, which also provides reasons to expand it further. President Pervez Musharraf has recently announced to build six dams, in phases, to ensure smooth availability of irrigation water. While the controversy about Kalabagh dam has subsided for the time being, at least, it is necessary to highlight some of the inefficiencies for avoiding the same in the forthcoming projects. However, it is also important to remember that this system is almost a century old and some of the problems are due to improper repair and maintenance rather than due to any inherent fault in the system.
According to some experts the water requirements of crops vary according to their stage of growth. As against this much of Pakistan's irrigation system has a continuous flow throughout the year. This results in over or under irrigation affecting crop yields. The irrigation system in Pakistan consists of two parts: 1) canals, branches, distributaries, and minors which are maintained by the government, 2) watercourses collectively maintained by the farmers. Losses in canals, distributaries and minors are usually high because most of the irrigation system in Pakistan is unlined. While irrigation department term the delivery efficiency at 75% farmers do not accept this, particularly those having lands at the tail-end.
The largest percentage of water is wasted due to badly managed watercourses. This also affected the groundwater table. Added to this are poorly-levelled fields, which lead to over supply of water in certain areas and hardly any water in other areas. Ideally at the time of designing and construction of irrigation systems drainage schemes should have been constructed. However, the fact is either the drainage system was ignored completely or whatever facilities were constructed proved highly insufficient due to excessive seepage. This has contributed to a rise in the water-table proving detrimental to the agro-economic structure of the country. The excessive seepage also renders available water highly insufficient.
Some of the experts say that the poor quality of watercourses is mainly due to inadequate allocation of funds by the provincial governments. Proper maintenance of the irrigation system is a matter of prime importance, as it has considerable bearing on cropping patterns and total agricultural productivity. Traditionally, the expenditure incurred remained within the receipt from irrigation, but lately the revenues are falling short of expenditure. It is also being said that recoveries are so meager that they do not cover normal operation and maintenance expenses. Provincial governments have been compelled to cut down on their provision for O&M costs. As allocations are not keeping pace with increasing costs, deferred maintenance is resulting in deterioration of the system, which is endangering adequate and timely availability of water.
Working out future needs of water depends on how area under cultivation, particularly irrigated, has to be expanded to meet the future requirements. Some of the analysts say that Pakistan can achieve enhanced production of various crops by improving yield, but no one can deny importance of water availability in attaining self-sufficiency target. Therefore, wastage of water has to be minimized due to limited availability.
Some of the analysts oppose construction of big dams due to the growing problem of water logging. They say: "Nature tends to move towards equilibrium and this is also true for the groundwater table. When agriculture was limited to the barani (rain-fed) and sailaba (riverine) areas, and to some extent to land irrigated by Persian-wheel wells, the water-table was in a state of dynamic equilibrium. But with the development of an extensive irrigation system, thousands of miles of unlined conveyance channels were dug. A new and extensive source of groundwater recharge was introduced - water from the conveyance system. But failure to develop discharge channels, to balance the new recharge, has disturbed the hydrological balance and set in motion the problem of a rising water-table."
Storage reservoirs are created to regulate river water supply and transfer flow, by holding water, from one season to another. Since rivers deposit silt in the reservoir, the storage capacity decreases over the time, reducing the dam's ability to ensure a sustained supply of water on a predetermined basis. In order to maintain a continuous supply, two actions are required 1) to reduce silt inflow through watershed management and 2) to continuously add new storage facilities to make up for lost capacity. However, it is also true that Pakistan has failed in adding any new storage facility after Tarbela, constructed nearly 30 years ago. This demands that new facilities be constructed on war-footings to increase storage facility to meet the growing demand.
The most important point to be kept in mind is that Pakistan has limited availability of water. It is also feared that if India constructs Baglihar or any other dam/barrage it could further contain water availability. It is obvious that water is very limited and is not enough to meet the future food requirements of the country. In the years to come, more emphasis needs to be given to the development and conservation of surface water. All available surface water will have to be exploited through the construction of reservoir facilities to fully regulate river flow and to replace storage capacity lost due to sedimentation. Many analysts are of the view that adding new storage facility will be of no consequence unless water distribution system is improved. The desired improvements are to 1) minimize spillover, 2) contain leakage due to unlined water courses, 3) leveling of fields and above all 4) regular maintenance of all types of watercourses, including canals.
One way of judging the adequacy or otherwise of a country's water resources is to assess the per capita water availability. In the past per capita water requirement was estimated at 1,000 meters. Water availability for each person in Pakistan is on constant drop, dropping from 1,160 meters per year in 1978 to 970 meters by the year 1990. Given the investment and implementation implications, the per capita availability will further drop to 780 meters per year by the year 2010, and continue to fall sharply thereafter.
According to various reports Pakistan's water resources are not only finite but exhaustible and no viable technology is available to generate additional water. Water availability will improve, but only in the medium-term while demand will continue to grow as the population increases. The gap between demand and supply will widen at an increasing rate. While there are no exact estimates of the quantum of water required it goes without saying that with a growing population, increasing urbanization and industrialization, water requirements will grow considerably.
Another report says that even if every drop of surface water is safely provided to the farmers, the projected water requirements of the country cannot be met on a sustained basis. It suggests following steps to overcome the issue:
1. Optimum output per unit water through optimal use of other inputs and supporting services.
2. Maximizing the rational management, conservation and efficient use of water, through improved water use efficiency by accelerating on-farm and command area management programs.
3. Use of modern techniques such as sprinkle or drip irrigation, wherever economically viable.
4. Recycling municipal and industrial waste water after appropriate treatment.
5. Introduction and installation of shallow pumping or skimming in saline groundwater areas.
6. Reducing the population growth rate through an effective family planning program.
7. Gradual reduction in the per capita consumption of cereals and the introduction of nutritious foods into the diet, improving the health of the common person.
8. Priority should be accorded to Class I soils in order to maximize the return per acre-foot of water applied. Class II and Class III soils should be utilized after the Class I soils have been fully utilized.
Prior to canal irrigation, agriculture was mostly limited to the regularly flooded riverine areas. The floods would recede, leaving fresh fertile silt and sufficient moisture in the soil to grow winter crops. As the pressure on land increased, human ingenuity devised ways and means to irrigate land distant from the river. In 1351 Feroze Shah Tughlaq constructed an inundation canal - to channel river water during periods of high flow - off the Jamna River to irrigate areas in the Hisaar District of India. In 1568, Akbar improved this canal and in 1626, Shah Jehan extended it further by adding the Delhi and Rohtak branches. In 1633, Shah Jehan constructed another canal off-taking from Madhupur on the Ravi river to irrigate a part of the Bari Doab as well as the Shalimar Garden in Lahore. All these canals subsequently ceased to flow for one reason or another.