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Pakistan has entered into the 21st century with a challenge to meet food and fibre requirements for its population and to achieve the export targets, water in Pakistan is becoming scarce, while major parts of conventional resources have already been developed.
In order to meet the needs of water and sanitation, food and fibre, industry and environmental protection, concerted efforts would be required to develop the next generation of resources.
Comparatively, the cost of these are likely to be larger than of the existing projects. Achieving sustainable development will, thus, be a major challenge and conservation and utilization of available resources will undoubtedly be one of the most critical tools for realizing these objectives.
River flows: Pakistan is one of the very few countries in the world whose water resources entirely depend upon one river system - the Indus Basin. Although, in addition to the Indus River System, the Kharan Closed Desert Basin and the Mekran Coastal Basin located in Balochistan have some development potential but it constitutes less than three per cent of the total surface water.
Of the total available annual flow of 145MAF in the Indus Basin, 105MAF is already being used through 19 barrages with 45 canal systems above and below rim stations. Average annual escapades below the Kotri Barrage going to the sea are 35MAF.
| The total water resources of three basins are | ||
| MAF | ||
| River system | Average annual flow | |
| Indus Basin | 145 | |
| Mekran Coastal Basin | 3.0 | |
| Kharan Closed Desert Basin | 0.8 | |
Flow below Kotri provides an indication of the available potential since it is the end result of all enroute inflows, outflows, gains and losses of the system. In order to develop and utilize the surplus flows, some provision has to be made for minimum flow below Kotri to meet daily requirements of drinking, cultivation of riverine area, forests etc., and occasional needs for pallah fish, mangroves and to check the saltwater intrusion.
It would be pertinent to reiterate that the yield of our crops is lower than the world average in spite of favourable combination of land and agro-climatic environments. The primary reason for it is inadequate availability of water at critical times during the crop growth.
The problem of already-restricted supplies is being compounded by the continuous silting-up of the existing reservoirs, which had initially provided some flexibility in meeting the demand-based water needs of crops.
Rainfall harvesting: Monsoon and westerly disturbances are two main weather systems that contribute to the rainfall in Pakistan. The average annual rainfall is 291mm (11.4 inches). Nearly two-third is received in the Kharif (summer), while the rest in the Rabi (winter). During the three Monsoon months (July-September) almost half of the rainfall is received.
While a substantial portion of the rainfall occurring in the cultivated areas of the Indus Plain is consumed by crops as a consumptive use, in the foothill areas of Pakistan rainfall gives rise to flashy hill torrents, and a major portion of the flow goes waste, in the form of evaporation. From the development point of view the potential of flows in hill torrent, Pakistan can be divided into 13 major regions:
The hill torrents bring in flashy floods of short durations but of high magnitudes. Due to steep gradients, flood flows move with enormous velocity which results in the erosion of banks and bed of channels.
Flood flows debauching onto the plain areas are generally charged with high silt contents which preclude their management by dams or reservoirs. As the flood flows traverse the flatter areas, they rapidly deposit their silt load as a result of reduction in velocity.
Silting and scouring phenomena are largely responsible for frequent changes in flow regime and shifting of flow paths of hill torrents that are typical of geological young "fans".
Unpredictable and erratic nature of floods and high silt contents thus pose a serious challenge to the ingenuity of water planners and engineers for their economic management. Presently, a major part of hill torrent runoff not only goes waste but also causes untold miseries further aggravating conditions in the areas which are grossly underdeveloped.
A rational planning of the existing water resources can ensure a systematic development of agriculture to lay the foundation for the socio-economic uplift. The conservation of flows of various hill torrent areas also conforms with the overall national planning for bringing additional areas under cultivation so as to produce more food, besides, improving the socio-economic conditions of the local population.
The total development potential of hill torrents is about 17MAF of which 5MAF has already been conserved through the construction of more than 500 structural interventions such as delay action dams, reservoirs, dispersion/diversion structures, flood retaining walls, etc.
Thus, gross balance development potential is about 12MAF for which 1,204 sites have been identified in 13 major hill torrent areas, with financial requirements of about Rs40 billion.
Glaciers and snow: Glacial area of the Upper Indus is around 22,500sq km, where on an average three to four meters of snowfall occurs every year. The Upper Indus catchment contains some of the largest glaciers in the world outside the Polar Regions.
Glacier area of the Kabul River is located near Unai Pass of the Southern Hindukush, while glacial and snow melt area of Chenab and Jhelum rivers are located in the Occupied Jammu and Kashmir.
The right bank tributaries of Jhelum River i.e., Kunhar and Neelum rivers carry major share of the snow melt, primarily, situated in Pakistan or along the Line of Control. Glaciers and snowmelt contribution is 85 per cent in the case of Indus, 80 per cent for Kabul, 75 per cent for Chenab and slightly over 50 per cent for Jhelum River.
It is estimated that the total volume of water stored in the glacial area of Indus River is about 340MAF, while the volume of water stored in glacialized area of Kabul, Chenab and Jhelum Rivers is 300MAF.
The yearly contribution of flow at rim stations as a result of melting of snow and ice is over 110MAF. The formation and melting of snow and ice in the glacial area, is in a state of equilibrium.
It must not be disturbed to get additional water benefits during drought conditions by resorting to, otherwise, highly tempting artificial techniques. If equilibrium is upset, the sustainability will be destroyed leading to disastrous consequences. Accordingly, no additional development potential is considered available from this valuable resource.
Groundwater: The readily available groundwater resources of Pakistan have played an increasingly important role in meeting the country's food and fibre requirements.
Groundwater now supplies around 45 per cent of crop water requirements in the country. The reservoirs underlying the Indus Plains are an inherent offshoot of the canal system, and are of immeasurable value in poverty alleviation in Pakistan.
Groundwater use permits farmers to exercise a greater control over the available water and results in timely application of water for crops. This has transformed the concept of low and uncertain crop yields to more secure and predictable form of crop production.
Even away from the Indus Plains in the highland areas of Balochistan and North West Frontier Province, groundwater has been crucial in supporting the agricultural sector. It is, therefore, imperative that long-term sustainability of groundwater, as a resource, is maintained to ensure the growing food requirements of the country.
From the point of view of availability of groundwater, the country can be divided into two major areas, the predominantly canal irrigated Indus Plain primarily located in Punjab and Sindh, and the areas of the NWFP and Balochistan with a limited groundwater development potential in a few localized areas.
During the last 30 years or so, spectacular increase in the number of private tubewells has changed the underground paradigm entirely. In several groundwater areas, there has been a complete Volta face.
Where some years ago high groundwater was a major threat, water levels have now declined due to private tubewells development. However, the pace at which the groundwater exploitation has unfolded has added complexity of its management.
The number of users is over 2.5 million farmers, who extract groundwater through their own tubewells or buy water from their neighbours. Their behavioural patterns are highly variable and they understand little about any adverse interaction which is likely to result due to unsystematic and erratic nature of groundwater pumping.
Their major interest is to pump ever more water to meet the rising crop water requirements. In many region, the impact on the groundwater resources is alarming; levels are declining rapidly to infeasible pumping depths, and there is intrusion of saline water in the fresh groundwater areas through lateral or upward movement.
Existing number of private tubewells in Pakistan is over 700,000 and annual groundwater extraction through private tubewells under the normal hydro-climatic conditions is of the order of 42 MAF. The province-wise sustainable development potential is:-
(MAF
Provinces Sustainable potential
Punjab 36
Sindh 8*
NWFP 2
Balochistan 2 * Potential can be further increased to about 14MAF (65 per cent of annual recharge) by using latest state-of-the-art techniques.
Development potential and requirements: Remaining development potential of water resources is approaching a stage where complex factors involved, require fine-tuning to permit sustainability.
Surface-water resources have some potential for development that are not fully exploited, while groundwater sources require system controls and a regulatory body to permit private operations to enhance production.
Pakistan is facing increasing water needs, by growing population, increased urbanization, higher standards of living and by an agricultural policy which has emphasized on expanded production for future.
The development potential of the three water resources of Pakistan is summarized as:
(MAF)
Resource Development potential
River flows 22
Rainfall harvesting
(hill torrents) 12
Ground water
a) 6
b) 12*
* Under ultimate conditions, with the latest state-of-the-art techniques. It has been estimated that the population of Pakistan will be around 221 million by the year-2025. In order to meet water requirements across various sector by the year 2025 i.e., agriculture, water supply/sanitation, industry etc, the country would need additional water to the tune of 20MAF at the farmgate for agriculture and 8MAF for other sectors.
Agriculture requirements are based on the assumption of 50 per cent increase in the yields of crops with non-water uses, like better seeds, fertilizers, pesticides and better agronomic practices for which potential of 300 per cent exists in Pakistan.
Salient features for consideration: Water resources of Pakistan are required to be managed in view the following perspectives:-
* Flows of the Indus Basin are highly uneven in terms of time. Variation factor in high flow and low flow is as much as 100 times over. More than 85 per cent of river flows are concentrated during Kharif, while only 15 per cent flow are available in Rabi as opposed to the irrigation requirements of 60 and 40 per cent in Kharif and Rabi, respectively. The year-round agricultural requirements can only be met if required resources are available during both the seasons.
* During low flow periods, Punjab has the flexibility to meet water requirements through groundwater exploitation in about 75 per cent areas directly or by mixing with canal water. This flexibility is available only in 25 areas of Sindh.
The potential of groundwater extraction in other two provinces is very limited. Thus, availability of additional river flows at critical times is more crucial for Sindh as compared to Punjab.
* After the construction of Mangla, Tarbela and Chashma reservoirs, the provincial canal diversions increased as:
* Including 3MAF above rim stations for civil canals.
**The increase in canal diversions is primarily during Rabi season.
* After the construction of Mangla, Tarbela & Chashma reservoirs aggregate releases from storages commencing from commissioning up to June 2004 are 467MAF, while 1,001MAF has flown to the sea. Present average annual releases from storages are 15.12MAF.
* After the commissioning of Tarbela Dam, practically no project was undertaken to develop additional water resources till the year 2000, when the Fast Track Projects under Wapda Vision-2025 Programme were initiated.
It is anticipated that the execution of projects identified under it would make sterling contribution to national development by increasing water and cheap hydropower to meet the growing requirements.
* Aggregate storage capacity of dams on the Indus Basin Rivers is 13.64MAF, which is nearly 9 per cent of the average annual flows at rim stations.
*India has 4,291 large dams with a storage capacity of 205MAF or 30 per cent of average annual flows.
* Presently 1,700 large dams are under construction in the world of which 970 are being constructed in India along with 27 link systems which would enhance storage capacity of Indian reservoirs to over 400MAF.
* The US has 6,575 large dams with a storage capacity of 1,420MAF.
* China has more than 22,000 large dams with a gross storage capacity of 2,280MAF.
* Storage capacity of existing dams in Pakistan is depleting at the rate of 150,000 acre ft/year. (0.15MAF per year). The average annual increase of Pakistan's population is 3 million, which requires additional 2MAF of water to meet the requirements across various sectors each year. Thus, Pakistan requires additional water resources of 2.15MAF per year.
* Every year provincial conflict arises during late Rabi and early Kharif in view of scarcity of water, which is bound to increase with time because of progressively higher requirements.
* Karachi is perhaps the only mega city which is not located on the bank of a river. Its water supply and sanitation requirements should be over and above any provincial formula for water distribution. Adequate quantities are required to be made available from the Indus River System.
* Water scarcity is not a severe problem at the rational level, nevertheless at times; there are serious imbalance problems due to high temporal variations in flows.
* With the shortage of canal water, the farmers resort to excessive exploitation of groundwater. In three drought years (1998-1999 to 2002-2003) over 100,000 new tubewells were installed in Punjab and Sindh and lopsided// unsymmetrical groundwater exploitation increased resulting in abnormal lowering of water table levels and salanization of aquifers.
* The problems of food shortage and drought are very severe and the whole nation has a stake in averting them through better management of water resources. Very soon, the stark reality of food shortage will make it necessary to reach a provincial consensus on how to deal with these differences and thereby remove the threat of famine in the country.
* If we want to evade future inter-provincial and inter-regional conflicts, optimal development of water resources is sine qua non. The conflicts are bound to grow with time in view of progressive shortfall in the system.
It would not be a wise policy to defer decision-making at the national level, merely to postpone the consequences to future date. As the shortages grow, the ultimate result is bound to be disastrous for the country.
* Basic facts about water resources in Pakistan will perhaps impress upon the nation that, we should redirect and channelize our natural resources, skill and potential to translate the dreams envisioned by Father of the Nation for economic self-reliance into a reality.
| MAF | ||||
| Province | Pre-dams | Post-dam | % Increase** | |
| Punjab | 47.69 | 54.02 | 13.27 | |
| Sindh | 35.56 | 44.47 | 25.06 | |
| NWFP | 4.66 | 6.16 | 32.19 | |
| Balochistan | 0.62 | 1.80 | 190.32 | |
| Pakistan | 88.53 | 106.45* | 22.24 | |
