Water Management and Reservoirs in Pakistan Dr Zaigham Habib

Natural river flows vary in patterns as do their sources in provision. Snowmelt and rainfall, two major sources of river water across the world, undergo huge changes in size to shape flows of water as it travels from foothills to lower plains and deserts. Hence, floods or water shortage.

For centuries, communities have been building surface storages to collect water for agriculture, industry, infrastructure and domestic use. The development of agriculture increased the need for having reliable water supply in the plains over the seasons. As techniques progressed, huge canals were built in the farming regions. Hydel-power generation gave impetus to water storages in industrially developing countries. To support the spread of population and industry, rivers were increasingly controlled, stored and interlinked. Trans-boundary water rights became another reason to control and store the flow of a river.

Depending on regional autonomy of the states, natural topography, number of rivers, type of agriculture, and dependence on hydraulic energy, economic conditions of a country, downstream acceptance and donors' approach, reservoirs are linked to socio-economic growth. Surface reservoirs collect river water during the high flow period, including floods, for use during the low flow period. They also regulate water for secure and reliable supply for industrial and urban use. Most North American and European dams, built during the last hundred years, fall under this category. River size and natural topography determine the size of reservoirs built for hydropower generation, the most beneficial and cost effective use of water storage. Small dams get water from rainfall and flashy streams in marginal water availability regions.

Post World War, North America and Europe modernized water control and supply systems, for high efficiency of water use, adequacy of water supply and high economic returns. Physical development of infrastructure included surface reservoirs, river training, lining of watercourses from rivers to the field channels and the drainage systems. International donors appreciated the economic benefits of investment in water projects across the world.

South Asia, a region with quick spread, has been slow in modernizing water systems, including the development of reservoirs. What is called “modern irrigation network” in the region consisted of 'run of the river canal', only controlled at the headworks, and the gravitational water supplies to farmers. Particularly in the Upper Indus Basin, such low-cost systems were spread over big areas of high aridity supplying only a fraction of water required by crops. This “scarcity by design” (ILRI , Mollinga) was aimed to protect communities against famine and engage maximum population in agriculture (Indian Commission on Agriculture -- , Michel Arther 1967). An in-built character of these systems is “water stress” and a demand for more water. However, inter-river transfer of water across the Indus started in 1932. Until 1967, 150 years after its development, the Indus and canals network was the biggest contiguous irrigation network without any reservoir and 70 percent of the cropped area having the “scarcity by design”.

The first reservoir of the Basin, Mangla, was built “as a replacement works”, storing and transferring water from the River Jhelum (the western tributary of Punjab) to the command areas of two eastern tributaries, Ravi and Sutlej. As a part of the replacement works, India built four reservoirs on these two rivers storing finally all of their flows, except for heavy floods. The second big reservoir of Pakistan, Tarbela on Indus, is also contributing to the “replacement works” through two big link canals, Chashma-Jhelum and Trimmu-Sidhnai.

Pakistan's water sector went through an important planning process between 1960 and 1965, which is hardly quoted in its real context. World Bank experts carried out an “Indus Special Study” on the estimation, development and management of water and power resources of West Pakistan. The experts, headed by Pieter Lieftinck, A. Robert Sadove and Thomas C. Creyke, produced a report titled “A Study in Sector Planning the development of Irrigation and agriculture”, which suggested three major changes to the philosophy of water management in the Basin:

• High feasibility of surface storage in the irrigated agriculture and power sectors of Pakistan recommending full storage and use of Kharif (monsoon) surplus water in Indus till the year 2000.
• Shifting agriculture towards high input-high yield crop systems - making system as much crop demand based as possible.
• Basin level water ownership and management resulting into the creation of Water and Power Development Authority.

However, after 1978 Pakistan could not continue with reservoirs. The reasons were local as well as international. Donors' interest in funding big irrigation schemes, especially big reservoirs, decreased in the eighties and the nineties. The environmental and demographic consequences of big reservoirs were widely criticized, along with the low economic efficiency of agriculture. Within the country, regional water sharing conflict and the objection of lower riparian to upstream water control could not be fully addressed. Despite satisfactory performance of two reservoirs built between 1967 and 1978 in Pakistan (commended by the World Commission), an effective Indus Basin approach could not be evolved and implemented. The impact of developments inside and outside agriculture could not be synthesized and integrated in the planning and management of water resources in general.

Because of low development of other sectors, pressure on agriculture and its extension has gone beyond the planning of 1965. Other water use sectors have emerged as competitive at the Basin and regional levels. All water bodies, including rivers, lakes and groundwater aquifer, are facing sustainability and conservation threats. Water availability has fallen very short of demand projections. To address the water shortages in the face of a “required extension of agriculture”, the government has launched a campaign to convince all regional stakeholders of the Indus Basin on the construction of “a series of new dams”, recommended since 1965.

The pronounced factor in the dam debate is regional political disagreement on the location of the next surface reservoir. The technical debate, limited in its arguments and sophisticated scientific analysis, is based on many underlying managerial and economic factors.
International Debate on Dams

When the World Commission of Dams (WCD) completed its report in 1990s, more than 40,000 dams were criticized for disturbing nature and generating inequitable benefits. The draft report of WCD was broadly criticized for its too much focus on environment while ignoring agriculture. The report listed out negative impacts of reservoirs and inequitable distribution of economic benefits of reservoirs across the globe.

“The impact of dams upon natural ecosystems and biodiversity has been one of the principal concerns raised by large dams. Over the course of the past 10 years in particular, considerable investments have been made in the development of measures to alleviate these impacts. Yet today widespread concern remains that despite improvements in dam planning, design, construction and operation, they continue to result in significant negative impacts to a wide range of natural ecosystems and to the people that depend upon them for their livelihood. Each river basin contains many natural ecosystems including not only the aquatic habitats associated with water in the river channel, but all of the elements of the river catchment that contribute water, nutrients and other inputs to the river. These ecosystems include: the headwaters and the catchment landscapes; the channel from the headwaters to the sea; riparian areas; associated groundwater in the channel/banks and floodplains; wetlands; the estuary and any near shore environment that is dependent on freshwater inputs. These ecosystem yield products such as wildlife, fisheries and forest resources, and are of aesthetic and cultural importance to many millions of people. Diverting water to dams alters the natural distribution and timing of stream flows. This in turn changes sediment and nutrient regimes and alters water temperature and chemistry, with consequent ecological and economic impacts. Reduction in downstream annual flooding, in particular, affects the natural productivity of floodplains and deltas.”

The report adopts a cautionary approach in concluding that “high degree of uncertainty and limited predictive capacity argue forcefully for adoption of a precautionary approach to dam development. Wherever possible, dams and their impacts should be avoided. Where avoidance is not possible, capacity to manage the dam in a flexible manner and so adapt to improved understanding of ecosystem requirements, should be incorporated into dam design. This precautionary approach should be recognized as a central feature of planning, design and management of dams, especially as many are probably irreversible (WCD)”.

The report suggests eight measures while taking up a reservoir:

• Recognize the important role of natural ecosystems in contributing to sustainable development. Conserve and enhance these ecosystems and their value to society.
• Recognize the importance of biodiversity and promote its conservation.
• Recognize and manage for uncertainty.
• Adopt environment friendly measures
• Maximize adaptive capacity.
• Promote incorporation of environmental management features into dam design.
• Promote the development of national legislative frameworks.
• Promote application of tools to foster ecosystem health. (I) Environmental Flow Releases. EFRs are being used in 25 countries and today serve as the single most important tool for managing the ecosystem and associated impacts of dams. (II) Ecosystem Health Indicators.

Donors hung back investment in big reservoirs and irrigation projects after the report. However, the need for food security, uneven development of natural resources across the globe and isolated local processes could not bring developing countries towards a comprehensive and environmentally friendly planning of water resources. During the last 10 years international research institutes have partly pulled out from developing countries.

“Dams, important to large-scale irrigated agriculture, have come under increased scrutiny. The World Commission on Dams (2000) recognized that “dams have made an important and significant contribution to human development, and the benefits derived from them have been considerable,” but in too many cases “an unprecedented and often unnecessary price has been paid to secure those benefits, especially in social and environmental terms, by people displaced, by communities downstream, by taxpayers, and by the natural environment.” The report outlined a way forward with an innovative rights and risks approach. Despite the efforts to incorporate all points of view, many countries and communities do not embrace the report and see it as presenting too many barriers. They would like to maintain the option for construction of dams for economic development. Nevertheless, it can be expected that public investments in large dams and irrigation projects will be increasingly difficult to justify.” (IWMI 2001).

“On the one hand, the fundamental fear of food shortages encourages ever greater use of water resources for agriculture. On the other, there is a need to divert water from irrigated food production to other users and to protect the resource and the ecosystem. Many believe this conflict is one of the most critical problems to be tackled in the early 21st century”. This was a key conclusion of the Framework for Action exercise of the Global Water Partnership (GWP,FFA, 2000, p58).

The need for water resources development
During the last three years, the need for hydropower development has been emphasized again because of non-availability of alternatives. Gas and coal resources of the world are on the decline. The two energy sources also create high pollution during generation. Nuclear energy, the only potential alternative, is not safe yet, and not politically acceptable either. Hence, the international donors came back, with their support for big reservoirs and clean-energy generations. The following quote from the “UNEP Executive Director Klaus Toepfer at the World Water Week High Level Panel on Water and Energy” reflects the UN agenda:

“Hydropower provides perhaps the strongest example of the close link between water and energy. Traditionally regarded as renewable energy, hydropower represents a largely under-utilized resource, especially in the developing world where energy needs are most acute. However, because of its link with large dam projects, which are broadly perceived as often environmentally and socially harmful, hydropower remains the focus of heated debate. Both the positive and the negative aspects of water and energy use are central to the UN Millennium Development Goals, eight time-bound achievable objectives, adopted by the international community in 2000. Together these goals represent a set of minimum targets for eradicating extreme poverty and hunger, empowering women, improving maternal and child health, promoting environmental sustainability and encouraging new and better partnerships for sustainable development that must be achieved by 2015. Strategies for sustainable water use and energy generation are particularly relevant to eradicating extreme poverty, promoting gender equality, improving the health of women and children, as well ensuring environmental sustainability, which UNEP maintains is the foundation on which humankind's long-term welfare ultimately rests.

Fulfilling water and energy requirements to achieve the Millennium Development Goals will require additional water collection and storage capacity and increased electricity generation and supply. Using water reservoirs to generate electricity addresses both issues. However, hydropower is just one from a basket of solutions. The debate about the performance of large dams and their social and environmental effects in the 1990s led to the establishment of the World Commission on Dams (WCD). While the full WCD report findings and recommendations have not achieved worldwide acceptance, the UNEP considers them a source of valuable information and advice that will inform the development of water and energy strategies. The UNEP says the debate is not between small and big dams but between good dams and bad dams. The UNEP Dams and Development Project is working to promote an improved decision-making on dams through multi-stakeholder dialogue. The project aims to strengthen national regulatory frameworks and international guidelines.

The role of hydropower was highlighted by the Johannesburg Plan of Implementation which called, with a sense of urgency, for substantially increasing the global share of renewable energy sources, hydropower included, with the objective of increasing its contribution to total energy supply. The Political Declaration of the International Conference on Renewable Energies, held in Bonn, Germany in 2004, also included hydropower as a renewable source. It acknowledged that renewable energies combined with enhanced energy efficiency could significantly contribute to sustainable development: by providing access to energy, especially for the poor; mitigating greenhouse gas emissions; reducing harmful air pollutants, thereby creating new economic opportunities; and enhancing energy security through cooperation and collaboration. Worldwide, hydropower represents just 19 per cent of total energy production. Two-thirds of the total economically feasible global hydropower potential in the world mainly located in the developing world still remains undeveloped. Africa as a whole has tapped only 6 per cent of its hydropower potential.”

The Dams and Water Debate in Pakistan
In 1947, Pakistan came into existence with 80 percent of its population living in the rural areas and fully relying on agriculture. The predominantly irrigated agriculture was confined in the Indus basin covering of 30 percent of Pakistan's land and hosting more than 90 percent of its water resources.
Conceptual and management gaps

After 1960, water resources management moved from the “operations of a run of the river system” to the regulation of “a controlled” system. An objective study carried out in 1965 recommended a gross storage of 30 maf, big drainage system covering the whole basin and full use of water resources till 2000. Locations of the potential reservoirs were also identified by this study. This exercise by the top world consultants (Liftnick --, 1967) has been widely referred to in water projects. Conceptually, outlines of a controlled and managed water resources system could not be evolved and some vital gaps emerged during the last 40 years:

Water demand (in agriculture and other sectors) was not recognised and planned to be addressed. The basin level studies carried out in 1978 (RAP) and 1991 (1991) again recommended more storages and full utilization of water resources, but, could not evolve and discuss measures to manage and control water demands. The dichotomy continues to exist in the planning of water resources development and use. Even after the construction of two reservoirs in 1967 and 1978, the operational criteria at the main canal and lower levels were not changed. The run of the river system based seasonal allowance was not officially and legally changed. The excess water was distributed based on the “indents” (request of the local manager), representing a combination of capacity constraints and local demand. This process generated the concept of “historical diversions”. Historical diversions are neither based on the design criteria, nor on crop. With a slow “shift of supply responding to the indents” the design targets are manipulated without any criteria. All planning and management documents remain simple and empirical limiting the discussion and comprehensive understanding of the system. While the physical integration of river network was enhanced in the seventies, a complex integration with the groundwater systems started developing then. It reached an optimum in the nineties, and an integrated basin level vision could not be evolved at the analytical and the planning level. The basin level planning and regulation failed to address the issues of water bodies in terms of their socio-economic values, status, safety and replacement. The planning documents and regional agreements in the Indus Basin generally lack proper assessment and mentioning of the “water bodies” security. The Indus Waters Treaty of 1960 evidences this attitude or ignorance of managers. The treaty is silent on the natural ecosystems of three eastern rivers, and was not even later on considered in the replacement works. Arguments in favour of higher regulation and exploitation of water resources solely come from the “enhanced agriculture cost”. Discussion on the cost, benefit and sustainability of these systems remains superficial. Despite high benefits and needs, hydropower is neither planned nor projected as an independent sector. The regional water scarcity and cost benefits are uneven at the spatial scale, causing higher political and administrative interference in resolving water issues. The basin and sub-basin level institutional integration and links could not be developed in the Indus Basin. WAPDA remains a federal planning and monitoring institute devoid of the qualities of “a basin level organization”, while provincial irrigation departments remain regional operators. Because of this basically administrative mode of operations, public knowledge about water issues remains limited at the common and intellectual levels. To put the reservoir debate in the context of water resources management following Key features of Indus Basin hydrology Water demand and Supply Gap Environmental Water needs Regional Water Interests

Water availability in the Indus Basin
Indus, the trans-Himalayan river of southern Asia, is one of the world's longest rivers, with a length of 1,800 mi (2,900 km). Its annual flow of 272 billion cu yd (207 billion cu m) is twice that of the Nile. It rises in southwestern Tibet and flows northwest through valleys of the Himalayas. After crossing into the Kashmir region, it continues northwestward through the Indian- and Pakistani-administered areas and then turns south into Pakistan. Swelled by tributaries from the Punjab region, including the Jhelum, Chenab, Ravi, Beas, and Sutlej rivers, it widens and flows more slowly. It has supplied water for irrigation on the plains of Pakistan since early times. (Indus River Concise Encyclopedia Article)

After the Indus Basin Waters Treaty with India, Pakistan has a right only on three western Rivers. Almost 80 percent of the water in the Indus comes from remote glaciers tucked in the majestic Himalayan and Karakorum mountain ranges, which border China and India, and the Hindu Kush, which borders Afghanistan. The rest comes from rains, especially during the monsoon season from July to September. Since most of Pakistan is arid or semi-arid, the Indus River System serves a vital national role. The watershed irrigates 80 percent of Pakistan's 21.5 million hectares of farmland, through a well-knitted network of canals. (The other 20 percent is fed by rainfall.)

Interconnectivity and Sharing of Rivers
The natural connectivity of tributary rivers of Indus is enhanced through inter-river link canals supported by the reservoirs. This interconnectivity provides flexibility in case of excess water availability and increases sharing competition in case of low availability. The distribution of water across the long distances daily provides room for the management and operational leakages.

Spatially uneven, erratic and low rainfall
The major contribution of rainfall occurs at the lower elevation closer to the foothills. Towards the south-west rainfall quickly decreases. The country is divided into five rainfall regions below the mountainous region, more than 1000 mm in the northwest, to less than 125 mm in two desert regions. About half of the Indus plains has rainfall less than 150 mm. The monsoon region receives 80 percent rainfall during one to three summer months. A small western region is exposed to the winter rainfall, positively influencing contributing to the Kabul river flows. The floods and droughts in the South Asian region are mainly contributed by the monsoon rains, which can vary in the fourfold annual range. The extreme events of floods and droughts disturb the average estimation of water availability. The estimated gross rainfall in the Indus Basin was 135 maf in 1994 and only 30 maf in 2000-01.

Groundwater Availability
After the seventies groundwater extraction has played an important role in agriculture sustainability in the fresh groundwater zone. The private tube well growth in Pakistan is scattered across the country, inside and outside the Indus Basin. The rain-fed and un-irrigated crop belt has converted into well-irrigated area. Groundwater quality is the major constraining factor in the groundwater use. The use of groundwater in the freshwater zone has sustained the agricultural development in the last 20 years. Fresh groundwater has become important both for Sindh and Punjab.

The groundwater is saline in 80 percent of the irrigated areas of Sindh. These areas are permanently waterlogged due to ineffective drainage and high irrigation supplies. In contrast to this planned agriculture, the riverine (sailaba) area along the Indus has better perennial access to the good quality water. A recent survey of the Sindh Forest Department has shown more than 41000 shallow wells only in one million hectare Sailaba land of Sindh (Baseline

Punjab is over-extracting its rechargeable groundwater and a depletion of aquifer is becoming irreversible in low rainfall areas. The total pumpage potential of 0.6 million tubewells installed in Punjab is higher than the canal supplies at the watercourse level. However, it has created a basic imbalance in the recharge-discharge potential. The over-extraction of groundwater is more than 15 maf in a dry year while the recharge could be higher in the range of 5 maf in a wet year (Pakistan Water Economy Running Dry World Bank 2005). On the average, groundwater deficit is 6 to 8 maf in Punjab and groundwater depletion is occurring in the areas of high cropping intensities and the population density. Preserving this resource base is a primary challenge in the Indus Basin water.

Industry mainly depends upon pumped water. The domestic uses in the rural and semi-urban sector mainly come from hand pumps or shallow wells. The supplies in the big urban centers are reaching a saturation level and a support from the river diversions is required.

River Flow and Distribution
Availability at Source
Despite concord on the gross river inflows, there are wide disagreements on the water available for development, and surface water scarcity and availability.

The total average water entering into the River Indus after 1978 is 145 maf, an agreed value. The maximum and minimum values of this period were 177 maf in 1994-95 and 101 maf in 2001. The contribution of western rivers is about 138 maf and that of the eastern rivers 7 maf. The western inflows have shown a decrease of about 2 maf after 1960 while the eastern inflows have decreased by about 25 maf (as shown in the figure below). The storage of eastern rivers on the Indian side has reached the capacity. Other than heavy floods, small flows available in Ravi and Sutlej are generated in their catchments in Pakistan.

The question is how much from these inflows will further decrease. A value of 2.5 maf is estimated for the western rivers, including the River Kabul, by WAPDA and Punjab Irrigation Department (personal communication with M. H. Siddiqi). No big disagreement exists on this value, which is linked with the future developments on the Indian side. Based on the existing trend, annual hydrograph of eastern flows will vary between 1 maf and 10 maf. The average expected value can be 4 to 6 maf.

Population Factor
Pakistan has reached the threshold of a water scarce country based on per capita gross water availability of the renewable water resources. This indicator is internationally accepted by the UN and other water-related organizations to indicate physical water scarcity of a country. According to the Food and Agriculture (FAO 2003), renewable water resources of Pakistan are 172 maf.

The calculations include rivers inflow, useable average rainfall, water generated outside the Indus Basin. If the average inflow remains constant with time, this indicator shows the impact of population growth highlighting the need of scarcity management and increasing important of domestic and urban water requirements. Per capita river water availability is shown in the Figure below using the actual river inflows of different years. This figure is important to understand human stress on the water bodies, groundwater and increasing need to independently plan for the domestic and household supplies.

Shortage against the Allocations of 1991
Out of 145 maf average inflow of all rivers below RIM (River Inflow Monitoring) stations, 114.4 maf is allocated for the annual canal diversions to the four provinces (WAA 1991). The Rabi-Kharif ratio of these allocations is 1: 2. The design allowances of Rabi are increased by about 3 maf. The average actual diversions between 1978 and 2004 were only 101.6 maf, while the maximum diversions were 111 maf. The limited surface storage and peak flow durations are two major constraints not allowing the system to draw more than 111 maf even under best conditions. The canals having about 4.5 maf allocation are in the construction phase (Raini, Kachti and Greater Thal). After their construction the maximum diversion may cross the 114 maf, while the average flows will remain at least 8 maf lower. The existing regulation is analyzed by Habib 2004, showing that:

• The actual capacity of the canals is more than the allocation by WAA.
• Reservoirs shift water from Kharif to Rabi while a part of storage is used within the Kharif season.
• The best diversion years have maximum storage plus an extended high flow period
• The monthly targets of WAA cannot be achieved without enhanced storage

Water Shortage against the Actual Demand
The demand-based approach for agriculture estimates water availability from all three sources at the use level against the crop demand. The approach is comprehensive but complex. The computations for demands involve coefficients representing climate, crop calendar and irrigation practices. The contribution of rainfall, canal supply and groundwater depends upon efficiency factors. A recent basin level study (Habib 2004) analyzed water demand and supply in the Basin by carrying out detailed water balances and comparing results with different previous estimates, including the forecast of WAPDA studies, Lieftink (1967), Harza and Mot. Macdonald (WSIPS 1990).

The water shortage in agriculture computed by this study varies from 10 MAF in a wet year to 25 MAF in dry year. The groundwater overdraft was 15 MAF during the dry year leading to a total deficit of 40 maf. The wet year has a gross excess recharge as well as net deficit of 5 MAF. Some important findings of this study are:

1. Full land potential is not supported by the water allocation or the actual availability of water resources. The irrigated agriculture is designed for low cropping intensities.
2. The water stress is the maximum during Rabi season despite higher than allocated diversions during the season. Water stress is also higher in the well irrigated areas.
3. Agriculture water demand has not been increasing linearly or as a function of area because new cropped areas have bigger share of the non-irrigated or well-irrigated areas having smaller impact on demand and higher water use efficiency.
4. The net water use efficiency has increased through groundwater recycling. However, groundwater depletion in some areas needs to be controlled by adopting a combination of three options; increasing canal supplies, increasing recharge through recharge basins or controlling groundwater pumpage.

A decrease in actual water uses in agriculture will happen if the present situation continues. The surface water availability is already decreasing as are the residual flows from the eastern rivers and the existing storage. Groundwater pumping is not likely to be curbed officially. However, the groundwater aquifer depletion can itself force farmers to reduce pumping.

The Natural Ecosystems and their Water needs
A general ignorance exists about the river water based environmental and ecological systems among the policy makers, planners and mangers. The water needs of these systems are even less acknowledged and accepted. This approach can be used as an indicator to evaluate the vision and potential of key organizations, like WAPDA, as basin level managers. However, sensitivity on the environmental issues is exceptionally high in Sindh. The province as the lower riparian has always brought in the issues of Indus delta, lakes and riverine water uses in dialogue. The actual management of environmental hazards is not commendable in any part of the basin. However, the sensitivity of the Lower Indus or Sindh can be justified. The interaction between local communities and natural water bodies have been stronger in Sindh because of unusable groundwater, high aridity and dependence of communities on the aquatic and ecological goods (fish, forest other vegetation). Sindh's insistence on water needs down Kotri has been finally successful in carrying out three environmental studies. The complete reports of these studies are still not available, while, the government has made public recommendations of a panel of experts:

• 5000 cusecs constant discharge is recommended downstream Kotri barrage in the river Indus to meet all water needs of the downstream delta.
• Below Kotri, releases will equitably share shortages of the system; these releases will be dealt like diversions to an irrigation canal.
• 5 maf average flood flows should go over 5 years, i.e 25 maf water should go down during the flood months of five years.

Questions could be asked about the practical implementation of five maf flood flows during a prolonged drought. Nevertheless, this quantification is a big achievement towards acknowledging environmental water needs.

The environmental water requirements outside the Indus delta are still not fully acknowledged. Some of these requirements, water uses by lakes and wetland, are partially fulfilled by the existing system, but not protected through allocations. A part of water replenishment of lakes and other ponds is accounted as water losses or managed through the time lags. The impacts of these uses can be seen from a systematic change in time lags between different barrages. For example, after a dry period or during winter cultivation, the time lag between two last barrages of Indus (Sukkur and Kotri) increases because a higher percentage of water is consumed by the extended river cross section and riverine cultivation. An estimated summer replenishment of all water bodies on Indus and its tributary rivers downstream Kotri is in the range of 5 maf.

The existing water access to the riverine areas has become an “unaccounted irrigation supply”. The areas close to rivers and wetland are favorite places for the shallow well irrigation. The river seepage during summer can create shallow water layer useable only for a small period. The riverine areas of the sweet water zone are more sustainable for the groundwater use. The potential water uses of all reported riverine areas (Soil Survey of Pakisatn 1992, Baseline Survey Sindh 2004) could be more than 8 maf (Study III 2005).

A totally neglected phenomenon threatening the natural morphology of rivers is extremely reduced or nil river flows for longer periods of time. The eastern rivers are the worst affected as could be expected. No water was released into two reaches of Sutlej in Pakistan for more than 300 days of a year during the recent drought. These waterways which function as active rivers during floods are being abandoned for years. The natural ecology of these rivers may not be affectively saved, as no organization in Punjab is concerned about their ecosystems.

Summing it up
The farm land water demand has been increasing. The support from the groundwater has reached the optimum level. The current level of cropped land cannot be maintained. Agriculture is drawing more water than allocated. The actual water diverted in Rabi is higher than the allocations of 1991 and the total design allowances. The non-perennial systems are benefiting more from the water management, and hence high increases for Sindh. The indirect river water usage has been increasing though groundwater pumping. A substantial amount of water consumed by the usage is neither accounted nor protected. Agriculture is mining groundwater aquifer, which is irreversible in highly cropped and populated belt, some areas of which are affected by the reduced recharge from the natural ecosystem of the eastern rivers. The environmental water needs should be protected and accounted for. A gradual depletion of water bodies can decrease the resilience of Indus river system. The domestic and industrial demands, which are smaller in size, are going to have more dependence on river water.

The Issue of Reservoir in the Context of Water Demand
The need for hydropower in Pakistan is not disputed, and is supported by the donors like the World Bank (Water Economy of Pakistan Running Dry, 2005), and so, a big reservoir for electricity generation is an option stakeholders agree on.

There are gross water shortages in different sectors. Even the allocations of 1991 cannot be achieved without more storage. However, future potential usage is more than the average available water. So, we need to set priorities. Punjab is always in favour of new irrigated land with thinly spread water supply (To some extent this is spatial replacement of the agriculture land and so, needs a separate discussion). However, within the province a choice is to be made between replenishing groundwater depletion and spreading agriculture to the new lands.

Sindh has surplus water for the acknowledged needs in summer, while all water shortages (agricultural, drinking and environmental below Kotri) exist in winter and can increase with the depletion of the storages. Primarily, all direct and indirect water uses from the flood recharge in Sindh are not accounted and protected. Sindh has not gone through the required remodeling of the irrigation system to address some inbuilt constraints of the irrigation system and legally expand its irrigated land. It has kept the system conceptually close to the “run of the river summer agriculture” despite much higher Rabi supplies after 1978 and a big change over the areas where farmers can combat water logging. The external factor can be defined as a “historical regional wisdom” to secure more river water by the lower riparian, even if it could not be used. There is a water sharing agreement of 1991, but any upstream development will decrease the water entering into the lower Indus. This explains Sindh's insistence on having no upstream canals.

The North Western Frontier Province and Balochistan can benefit if new diversions are provided to the provinces. Even non-perennial canals will take advantage during early and late Kharif periods.

A proper cost-benefit for each province, however, is missing. This could not be a simple and conducive exercise by external consultants. Rather, it should be based on provincial agriculture plans and a realistic planning for the future within the provincial shares of river water. The lake of basin and sub-basin level planning institutes can be mentioned here.

The Importance of Location
Carryover dams are built when the expected storage is higher than the expected demand, and not when it is going to satisfy only a part of the requirement, an essential situation in the Indus Basin. The Kabul river flows, which are partly perennial, will make a key contribution to the reliable supply. Secondly, it is high time Pakistan established its water rights on the Kabul flows.

How Much Storage and How Many Reservoirs
The concept to fully “control and regulate” Indus waters continued existing by maximizing storage to the possible level and the “run of the river irrigated agriculture” approach hinged on the calculation of different “surplus water quantities” available below Kotri. An ambiguous presentation of both the schools of thought confused the public opinion on the availability of water for storage. It also muddled up water availability at a location with the storage impacts.

• An upstream storage is only a constraint on the water available at the location and downstream flood releases. Higher storage is considered as higher flexibility. However, in the case of Indus Basin, variable storage supplies are not a good planning option.
• The actual storage and release patterns of a reservoir are a real time phenomenon and so, need sophisticated model studies.
• In view of the existing planning not much water will be available downstream Kotri after constructing a reservoir and fulfilling existing environmental needs.

The Negative Impacts of a Reservoir
Every small and large dam has to manage negative consequences of the whole process from land procuring to filling of the lake. With passionate arguments on the benefits or losses of a new storage in the Indus Basin, the reservoir debate in Pakistan has already taken many years. A concise response from WAPDA can be expected on the eight-point WCD guideline rejecting some of the criteria by making an international reference. But this will essentially refine the whole argument.

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Dr Zaigham Habib is an expert on Pakistan's water issues

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7. Hunting Technical Services Ltd and Sir M. MacDonald & Partners (HTS/MMP). 1965. Lower Indus Report, Physical Resources-Groundwater, Volume 6, Supplement 6.1.3, 4 & 5. West Pakistan Water and Power Development Authority.
8. Indus Waters Treaty. September 1960. Signed by Shri Jawaharlal Nehru, Prime Minister of India and
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12. Klaus Toepfer, United Nations Environment Program 2004, High Level Panel on Water and Energy