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Water resources of Pakistan

Present status and future strategies

By Dr. Muhammad Saffar Mirjat
 and Abdul Samad Chandio
Professor and Assistant Professor,
 Sindh Agriculture University Tandojam
May 14 - 20, 2001

Indus valley, cradle of ancient civilization: The Indus valley has been the cradle of ancient civilization like those of the delta area of the Nile and the valleys of the Tigris and Euphrates. These three areas were the contemporary regions in which great civilizations flourished, about four to five thousand years ago. However, recent archaeological findings reveal that the Indus valley civilizations probably antedated that of the Tigris and the Euphrates. Excavations in the Indus valley have revealed that the dwellers of Moenjo-Daro, Kot Diji, and Harapa had established powerful empires. A stroll through the ruins of Moenjo-Daro and Harapa reveals that the houses in these cities were provided with all types of amenities. There were comfortable bedrooms, guestrooms, dinning rooms, porter's lodges, lavatories, handsome courtyards, drainage, fresh water wells, and tanks. The dwellings of Moenjo-Daro period are found so well finished and highly polished that these even match with that of today's then of prehistoric.

It is believed that the ancient people of the valley of Indus were outstanding in the field of agriculture and industry as compared to the civilization of contemporary period in Egypt and Mesopotamia. The textile crafts made from cotton are living examples of their expertise. Such was the glory of the ancient people of Indus valley; perhaps they were the first sedentary farmers of the world. The richness and wealth of the Indus valley was the greed of the foreigners. The valley of Indus has always been the cherished goal of the invaders and conquerors that followed one after another from the northwestern passes through the mountain ranges. The Aryans, the Iranians, the Graeco-Bactrians, the Parthenians, the Kushans, the white Huns, Muslims emperors, and Britishers plundered the rich valley of the Indus from time to time and ruled over the valley and northern India. Entire history of Indus valley reveals that one invader or another has treaded the present Pakistan. The Muslims of the sub-continent first tried to shake off a century old rule of British in 1857 and finally succeeded to drive them away in 1947, and the great valley Indus became part of Pakistan. Pakistan lies between latitudes 24 degree and 37 degree North and longitudes 61 degree to 76 degree East. Its surroundings include Iran on the west, Afghanistan on the northwest, Gilgit Agency, Azad Kashmir and disputed territory of Jammu and Kashmir lie on the northeast, India on the east and the Arabian Sea exists on its south.

Catchments of Indus river system: The Indus basin is a part of the catchments of the Indus river system that includes the northwest mountains, the Katchi plain, desert areas of Sindh, Bahawalpur, and the Rann of Kachh. The Indus and its major tributaries flow in longitudinal valleys in structural troughs paralleled to the mountain and invariably take an acute bend descending to the alluvial plains by cutting through mountains. These plains are stretched over a distance of 1528 Kilometers (950 miles) to the tidal delta near the Arabian Sea. The total catchment area of Indus River system spreads over 944,573 square kilometers (364,700 square miles). Of which 553,416 square kilometers (213,674 square miles) exist in Pakistan with a varying width of over 320 kilometers (nearly 200 miles) in the Punjab to about 80 kilometers (50 miles) in the narrow neck between the Thar Desert and the Khirthar mountains. The flat plain of Indus basin is made up of highly fertile alluvium deposited by the river Indus and its tributaries. Agriculture is concentrated essentially to this plain, where it has been developed by harnessing principal surface water resources available. Since, evaporation is high with meager and unreliable rainfall over Indus plains, hence, agriculture is wholly dependent on irrigation supplies. The river Indus and its tributaries are like a funnel, they rise in the northern mountain areas, receive water from various resources (snow, glacier melt, and rainfall), converge into a single stream at Panjnad (Mithankot), cover about 1005 Kilometers (625 miles) through the Sindh province, and finally discharge into Arabian sea.

Historical perspective: The Almighty Allah has gifted Pakistan with abundant water resources with water flowing down the Himalayas and Karrakurram heights from the world's largest glaciers, a free and unique bounty of nature for this land of alluvial plains. As a result of this natural resource, today we have the world's marvellous and the largest contiguous irrigation system that currently irrigates over 16 million hectares of land, out of 34 million hectares of cultivable lands available. This land lies within the plains formed by river Indus and its tributaries. Britishers started the barrage irrigation system during 1930s. However, before that the residents of Punjab, Sindh, and Frontier had constructed a number of inundation canals to irrigate their lands. In the Punjab, 38 such canals had been taken out of Sutlej, Indus, and Chenab rivers to irrigate areas around Bari Doab, Multan, Muzaffargarh, and Dera Ghazi Khan. In Sindh, water level of the Indus during summer had always been higher than the surrounding lands, thus, 16 inundation canals in this area had conveniently carried out the irrigation water during past century. However, British Army Engineers undertook construction and improvement of several irrigation canals in the sub-continent. Subsequently, remodeling/construction works on Bari Doab Canal; Sidhnai Canal, Lower Sohag, Ramnagar Canal, Lower Jhelum Canal, Kabul Canal, and Lower Sawat were completed by the end of l9th century. However, at the time of independence country had 29 canals to provide regulated supply to an area of about 11 million hectares, beside an area of about 3.2 million hectares irrigated through inundation canals leading from Indus and its tributaries. These main inundation canals included Upper Sutlej, Lower Sutlej, Shahpur, and Chenab in Punjab; whereas, Rohri, Fuleli, Pinyari, and Kalri in Sindh. However, after the construction of barrages these canals are no more inundation canals but get regulated water supply and some of them have become perennial while few are nonperennial.

We have entered into 21st century with world's largest and unified irrigation system that consists of three major reservoirs (Chashma, Mangla, and Tarbela); 19 barrages (Ferozepur, Sulemanki, Islam, Balloki, Marala, Trimmu, Panjnad, Kalabagh, Sukkur, Kotri, Taunsa, Guddu, Chashma, Mailsi, Balloki, Sidhnai, Rasul, Qadirabad, and Marala); 12 link canals; 45 irrigation canals; and over 107,000 water courses and millions of farm channels & field ditches. The total length of main canal system is estimated about 585000 Kilometer (36932 miles) and that of watercourses & field channels exceeds 1.62 million Kilometers (over 1.02 million miles).

Surface water resources: Irrigated agriculture was, still is, and will remain in future the backbone of Pakistan's economy. Nature has blessed Pakistan with abundant surface and subsurface water resources. These resources had been exploited and utilized for agricultural, domestic, and industrial purposes in the past and will continue to be explored in future. The river Indus and its tributaries provide the surface water. At the time of independence, we had about 67 MAF water available for diversion, this amount increased to about 85 MAF by the year 1960. At this juncture, the right of three eastern rivers (Beas, Sutlej, and Ravi) was given to India under Irrigation Water Treaty 1960, during this period, Indus Basin Project (IBP) was implemented with international assistance of the Wold Bank. IBP enabled Pakistan to acquire significant capability of river flow regulation through integrated system. By the dint of river regulation-cum-storage facilities of IBP and other irrigation developments on the river Indus, canal diversions progressively increased and peaked to about 108 MAF. The recent statistical data shows that the River Indus and its tributaries provide about 147 MAF during flood season. Out of which nearly 106 MAF is diverted into canals and is available for agriculture, while, about 32 MAF outflows into sea, whereas, over 8.6 MAF is considered as evaporation and seepage losses in the river system. It is worth mention here that during last 3-5 years hardly 2-5 MAF water has flown into sea, whereas, at least 12 MAF must be left to sea in order to control intrusion of brackish water.

Ground water resources: The Indus plains constitute about 34 million hectares (over 85 million acres) of cultivable land, which is under-lain predominantly by sand alluvium to a considerable depth. Annual recharge to ground water system of this Indus plain is estimated around 55 MAF, out of which about 48 MAF is within the commands of Indus basin irrigation system (IBIS). Presently, 39 MAF is being extracted annually. Ground water is also found in some rain-fed (Barani) lands, and inter-mountain valleys at depths varying from 100 to 200 ft. During 1950s, large area in the Indus basin became waterlogged and soil salinity increased adversely affecting the agricultural productivity. It was the time when government got involved and took initiatives in the ground water development. The efforts began to control the twin menaces of waterlogging and salinity by the way of providing drainage facilities. Government embarked on a series of SCARPs in the late 1950s aimed at lowering the ground water table by providing "vertical drainage" through large capacity deep tube wells. Because of better economic returns, priority was given to locating SCARPs in the areas with ground water quality suitable for supplemental irrigation, making the drainage a by product in effect. During past four decades, about 15000 SCARP tube wells have been installed by the Government in 57 projects covering a gross area of about 7.7 million hectares affected land for putting it back into production. Almost 75% of all SCARP tube wells were installed in the Punjab. About 81% of total tube wells installed in Punjab province are located in fresh ground water areas, whereas, remaining 19% tube wells have been installed in saline ground water areas. The tube wells installed in the fresh ground water areas have been pumping water directly into watercourses; thus, they are being used for irrigation in addition to canal water. However, the tube wells installed in the areas with saline ground water, discharge saline water directly into drains, from where it is being disposed of.

Soon after the initiation of the SCARP program,: Large-scale development of ground water was started by the private tube wells. According to latest reports issued by the Government of Pakistan, the number of private tube wells has increased from 27000 to over 400000 during period between 1964 and 1995. All of the 400000 private tube wells have been installed in fresh ground water zones and are being used for irrigation purposes. About 80 per cent of these tube wells are located in Punjab and supply around 40 per cent of total irrigation in the province.

Future of water resources and needs: One of the key issues to Pakistan is the growing population pressure, which is responsible for driving its water resource development. It has the world's fastest growing population that has surpassed the 140 million mark by now and is still increasing at an alarming rate of around 2.8%, which needs to be checked, whereas the growth rate in agriculture sector remains somehow lower than the demand due to limiting irrigation water. To keep up the pace of agricultural growth comparable to population growth, we must bring additional lands under cultivation. In order to achieve the required growth targets in agriculture, we will need estimated amounts of about 149 MAF by 2000, 215 MAF by year 2013 and about 277 MAF by year 2025. This scenario warns that Pakistan has already slid from water affluent country to a water scare country and already a shortage of over 40 MAF persists and it will increase to a projected water shortage of over 108 MAF, and 151 MAF by years 2013 and 2025, respectively. Since no additional water is available, it is better to improve the existing water system and land capabilities; otherwise, Pakistan will be facing acute shortages of food, fiber, and edible oils in near future. It is time to recognize our responsibilities and start taking steps in right direction. We must keep eye on the issues such as, inadequate management and inefficient operation of irrigation systems, poor water application & unequal water distribution, depletion of ground water resources, reduction in storage capacities of existing system, and wastage of summer river surpluses and slow agricultural growth.

Development potential and future strategies

Improve surface storage capacity: Future development of the country depends on water resources expansion and management. It has been recognized that more than 83 MAF water can be generated through various resources (See Table). These potential resources include; surface water 33 MAF, ground water 9 MAF, watercourse improvement 15 MAF, minor canals 5 MAF, and distributaries 21 MAF. According to a report of working group on water resources for the 7th five year plan (1987), no new storage have been created after the completion of Tarbela due to rising controversies over the construction of such reservoirs. Thus, it has become necessary to focus on small size irrigation schemes (storage on rivers). There is a need to construct small dams on rivers Indus, Jhelum, Chenab, and their small tributaries. The potential sites for these small reservoirs/dams need to be surveyed. However, some of these sites are located at "Sehwan-Manchar Lake, Chotiari depression, Hamal Lake, Skardu, Bunji, Kohala, Kunhar, Rohtas, Neelam Valley, Ambahar, Dhok Pathan, Dhok Abakki, and Thal Reservoir" those may be explored/utilized. The level of Mangla dam can also be raised to increase its storage capacity. Another option is to manage the existing irrigation system in a better way and undertake new schemes wherever possible.

Conjunctive use of ground water: Conjunctive use refers to the co-ordinate, combined, creative exploitation, and judicious use of ground water for sustained development. It deals with neither over extraction nor under extraction of the source. This option has technically and economically been considered as the most viable strategy in the past studies. But, the tragedy of this source is that the government has no effective control over the excessive pumping of ground water in some areas, hence, it has started to diminish in those areas. The ground water table has already started declining in 14 out of 45 canal commands. Due to over-exploitation of this resource, the sustainability of irrigated agriculture is facing a new threat in some of the canal commands in Punjab. This situation needs to be checked and addressed urgently. However, Indus Basin Irrigation System (IBIS) has a potential of around 48 MAF water within its commands and nearly 39 MAF of ground water is being extracted annually. This leaves with 9 MAF of water still available at this source. This amount could be extracted and utilized for irrigation purpose.

Increase the efficiency of existing system: The unchecked growth of population has increased pressure on land and water resources throughout the world; thus, it has become imperative to conserve our water supplies. New sources of supply are becoming scare and are unlikely to be constructed in the near future due to geopolitical reasons, naturally, the emphasis must be given on methods that can salvage the supplies already being lost within the irrigation system in the form of seepage. Several reports have shown that about 25 to 30% of the water is being lost in the conveyance system of the different countries of the world. A considerable amount of water is lost during its conveyance due to seepage in lengthy canals; lining of the system channels could reduce these losses. As reported by WAPDA, more than 5 MAF of irrigation water could be saved by lining the minor canals only, and additional amount of about 3.6 MAF could be saved by water course improvement (see, GOP, Sixth five year plan, 1983-88), this makes a total saving of over 8.6 MAF. However, due to financial constrains, it is not possible to line entire canal system thus, the portions with high potential of seepage and those located in the areas with high salt content could be lined, by doing so, not only huge quantities of irrigation water could be saved but also the risk of water logging and salinity could be reduced. This would result in saving of huge investments that otherwise are required for drainage projects. Also, the existing system requires development of new irrigation projects on non-perennial basis. It has been stemmed out in the Water Apportionment Accord (WAA) of 1991, that remodelling / construction of non-perennial canals should be taken, this would not only provide additional water for agriculture but also save a bulk amount (derived during monsoon) from flowing into sea. In this regard construction of Thar Canal in Sindh (non-perennial canal) should be undertaken to carry the additional water during monsoon season.

Water distribution: The proper management, efficient application, and uniform distribution of available water at farm-gate have remained major problems since the existence of the irrigation network. Increasing water demand, deferred maintenance, siltation of channel prism, excessive water by tampered outlets and illegal water extraction & theft all lead towards inequity in the system. It has even become increasingly significant over last two decades. There is inequity in distribution at all levels in the system. Inequity in water distribution between head and tail is of the order of between 20 to 50 %. The water is distributed amongst the farmers "as per turn system" on a watercourse and each farmer receives his share on the basis of the area owned by him. Each farmer is allotted a specified time period, in proportion to his land holdings. In other words, this system disregards the crop consumptive use, frequency, and timely application of irrigation water. The tail enders however, receive 10 to 12 % less share of water, because the allowance is based on the theoretical losses, whereas, the actual or operational losses are high due to silt deposits at the heads, grass growing on banks and in the beds, trees taking their toll of water, rodents, snakes and other insects having their abodes in the banks, variety of irregular cuts (nuccas) with borrow bits full of water, overtopping on banks, and seepage through bed. The present situation is that the head reaches are waterlogged and the tail enders do not have enough water to meet their minimum requirement which results in low crop yields. For maximizing crop production, this constraint in the system would have to be removed. Government should take measures to bring flexibility in the existing system to meet the crop water requirements. Similarly, outlets on a minor or distributary receive different amounts of water. Illegal pumping from canals and excessive losses add to the inequity in distribution. Also, due to poor operation and maintenance of irrigation systems, the water distribution is not equitable and reliable. This has shaken the confidence of tail users and has discouraged them to use nonwater inputs for increasing crop yields.

Due to shortage of water, the tail enders have been forced to use poor quality water without proper mixing, which has given birth to salinity in such areas. This problem could be overcome by lining the whole watercourse, again the investment becomes a constraint, it is not possible to line the whole or optimum length of the watercourses. The logical reaches need priority lining are the head sections where silt deposits and raises the bed level which reduces the flow of water, the sandy areas where the percolation losses are too high. The watercourse improvement, proper maintenance, and equal distribution would result in saving of more than 15 MAF of water.

Adoption of water conservation techniques: Water conservation can play an important role in sustaining agricultural development. This requires substantial improvements in water use efficiency, choice of suitable cropping pattern, growing water-efficient crops, and introducing modern irrigation application techniques (trickle. sprinkler etc.). It has been observed that once water reaches at the farm gate, then, it becomes the responsibility of farmer to use it. Farmers in Pakistan generally practice basin, border or furrow methods of irrigation but the application efficiency of these methods is very low and the water applied this way is not distributed uniformly on their fields. It is quite common to find a combination of over and under irrigation within a single field. Over and under irrigation conditions results in poor crop germination that causes yield reductions.

Recommendations

The unchecked growth of population has increased pressure on land and water resources throughout the world; thus, it has become imperative to conserve our water supplies. New sources are becoming scare and are unlikely to be constructed in the near future (except small dams) due to geo-political reasons, naturally, the emphasis must be given on methods that can salvage the supplies already being lost within the irrigation system in the form of seepage.

The second largest contribution to the total water availability comes from the ground water resources. This source has been exploited and very well utilized by the public SCARP and private tube wells. It can still provide over 9 MAF of water. This source could be exploited and judiciously used for irrigation purposes. However, in some areas groundwater is rapidly depleting due to excessive pumpage, government should take control in such areas to save them from depleting.

Water conservation programmes, such as, lining of minor canals. distributaries, and water courses should be accelerated, this would not only save the huge quantities of water, but would also help reduce problems of water logging and salinity in the country. Conjunctive use of water based on scientific lines should be encouraged. Efforts should be made to convert the present rotation-based-irrigation system to demand oriented system. Besides that, the modern irrigation application techniques (trickle, sprinkler etc.), that have potential to improve water distribution and water use efficiencies, should be introduced in the areas with water scarcity. Particularly, in Sindh province, for the development of Kohistan areas of Dadu and Karachi districts, such techniques would be beneficial, thus, may be initiated.

Since, improper management, poor operation and maintenance of irrigation systems, inefficient application, and inequitable distribution of available water at farm gate have remained major problems since the existence of the irrigation network. Increasing water demand, deferred maintenance, siltation of channel prism, excessive water by tampered outlets, and illegal water extraction all lead towards inequity in the system. Similarly, outlets on a minor or distributary receive different amounts of water. Thus, it is need of time that government should take appropriate measures to ensure equitable distribution, to stop illegal extraction, and to improve system efficiency. One way to over come these problems is to empower water users so that they can play effective role in managing the proper water supplies in their distributaries, minors, and watercourses. The past experiences show that irrigation department has failed to stop illegal theft and extraction thus irrigation distribution system needs to be privatized through water users associations. Also, irrigation water is supplied at negligible cost to irrigators that is why they do not treat water as a precious resource; therefore, there is a need to increase the water prices to make irrigators realize the importance of this asset.

Inspite of continuous efforts, the desired national targets have not been achieved. Low crop yields, decreasing fertility of lands, onslaught of water logging & salinity problems coupled with environmental degradation, improper water management, and miserable economic conditions of the farmers are the indicators that we have to work harder and go a long way to make improvements in agriculture sector through development and transfer of modern technologies of agricultural lands. However, to enhance optimum crop production per unit volume of water consumed, high yielding varieties should be introduced and better agronomic inputs (fertilizers and pesticides) should be applied on scientific basis. It is also recommended that the crops should be irrigated as per their requirements. The existing crop water requirements can theoretically be met by converting the existing irrigation system to crop consumptive use based system. This will allow water to be delivered at time of requirement and the amounts nearly matched to crop needs.

Farmer's organizations, water user associations, and private sector be involved in construction, operation, and maintenance of irrigation system. Such associations are conceived as a mechanism for creating a co-operative framework for improvement of watercourses.

Table. Scenario of water resources of the country

Surface water resources

Annual water flow
MAF

Water available at canal head (1947)

67

Water available at canal head (1960)

85

Rim station flow (1997)

147

Water diverted to canals (1997)

106

Water flow to the sea (1997)

32

Losses in the river system

8.6

Ground water resources

MAF

Recharge to groundwater

55

Recharge to groundwater within canal command

48

Groundwater pumping

39

 


 

Water required in future

Year

Water required

Water available
Surface + Ground

Shortage

.

MAF

MAF

MAF

2000

149

109

40

2013

215

107

108

2025

277

126

151

 


 

Potential for water development per annum

Water source

MAF

Surface water reservoir (Kalabagh, Basha, and Dassu)

17

Surface water reservoir (12 small dams sites proposed)

16

Water lost in canals and distributaries

21

Water lost in minors

5

Water lost in water courses

15

Groundwater

9

Sub-total

83

ITarar, 1997; 2Afzal, 1997; 3Khalid 1997; and 4WAPDA 1987; MAF = Million acre-feet.