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Introduction
The Indus Waters Treaty (IWT), signed in Karachi on 19 September 1960, by Indian Prime Minister Jawaharlal Nehru and Pakistani President Ayub Khan, was a landmark water-sharing Agreement. Negotiated under the auspices of the World Bank, the Treaty at that time was designed to settle water disputes by partitioning the Indus system's rivers between the two nations with emerging economies.
However, over six decades later, it is evident that technological progress and environmental shifts have outpaced the Treaty’s original framework.
The Treaty’s technical provisions are increasingly outdated, failing to account for modern advancements in dam engineering and construction as well as the volatile impacts of climate change. By adhering to 1950s era technical constraints, the Treaty has effectively stifled advancements and innovations in engineering and construction of dams as well as hydroelectric projects and sustainable sediment management. Technologically, the Indus Waters Treaty is ‘frozen’ in time.
The Indus River Basin
The Indus River system is characterised by two primary drainage groups: the Kabul River on the right bank and the Panjnad (Panchnad) on the left. The Panjnad represents the convergence of the Jhelum and Chenab with the Indus,classified as the ‘Western Rivers’. This system ultimately discharges into the Arabian Sea south of Karachi. Conversely, the Ravi, Beas and Satluj are designated as the ‘Eastern Rivers’.
In India, the primary tributaries include the Jhelum, Satluj, Chenab, Ravi, Beas and Ghaggar Rivers. While the Indus and Satluj Rivers originate in Tibet, the remaining five rivers originate within the Indian territory. Additionally, the Kabul River flows from Afghanistan to join the Indus in Pakistan. The key Indian outlet points of the sub-basins for the Western rivers in India are at Nimoo for the River Indus, Chakothi on the Indian side and Muzaffarabad in Pakistan-occupied Kashmir (PoK) side for the River Jhelum and Akhnoor for the River Chenab.
Salal Hydroelectric Project (690 MW)
The Salal Hydroelectric Project is a 690 MW run-of-the-river hydroelectric power plant on the River Chenab in the Reasi district of Jammu and Kashmir (J&K), India, commissioned by the National Hydroelectric Power Corporation (NHPC), a Public Sector Undertaking (PSU) company, in two stages (1987 and 1995). It was the first major hydropower project built by India on the River Chenab under the IWT regime in 1960.
The project features a 113-metrehigh, 487-metre long dam, designed to provide electricity to the Northern Grid, including J&K, Punjab, Haryana, Delhi and Rajasthan.
The Salal Hydroelectric Project on the River Chenab was conceived in 1920, with construction starting in 1970. The project consists of a rock-fill and a concrete dam. It has a unique combination of a 113-metre high, 487-metre long concrete gravity dam and a 118-metre high, 630-metrelong rockfill dam. The topelevation of the dam is 495.9 metres(1627 feet). The maximumwater level of the reservoir is 494.08 metres(1621 feet) and full reservoir level is 487.68 metres(1600 feet). Overflow spillways have been provided near to top of the dam having a crest elevation of 478.68 metres (1,570 feet).
As per original design six under-sluice spillways were provided at an elevation of 416.05 metres (1,365 feet) to allow for hydraulic sluicing of the sediments. This design of having a provision of under-sluices for hydraulic sluicing of the sediments was as per the international practice of sediment management in any dam.
Objection from Pakistan
However, based on objections from Pakistan, India was forced to plug the under-sluice gates which today has resulted in catastrophe consequences for this project. When the under-sluice gates were plugged, the dam lost its ability to ‘flush’ the river’s heavy silt load. Instead of water, the reservoir began filling with sediments (clay, sand and boulders). Within a few years, the ‘dead storage’, the area below the intake structure, was completely filled with sediments.Restrictions were also placed on the ‘operating pool’ of the reservoir limiting the dam’s ability to manage water levels effectively. India was also virtually forced to lower the originally proposed height of the dam.
Misuse of Provisions under the Treaty by Pakistan
The Indus Waters Treaty as per Article III, AnnexD, Para 8 (d) provides that“there shall be no storage below the dead storage level, unless necessary for sediment control or any other technical purpose, any such outlet shall be of minimum size, and located at the highest level, consistent with sound and economical design with satisfactory operation of the Project.”
The above provision under the Treaty considering sound and economical design with satisfactory operation of the project was completely ignored while plugging in the under-sluices of the project. Plugging of the under-sluices has resulted in filling almost the entire 284 million cubic meter (MCM) storage capacity of the reservoir with sediments within a few years after its commissioning in the year 1987.
As of today, more than 97% capacity of the reservoir has been filled up with sediments. Basically, this is the result of ignoring the sound and economical design with satisfactory operation of the Project as per provisions under the Treaty mentioned above. Figure 1 shows a picture of the reservoir of Salal Dam completely filled up with sediments. It can be seen that the reservoir has only sediments and vegetation and almost no water.
The sediment-filled reservoir of Salal Dam is leading to significant wear and tear of the underwater parts of the generating units in the power house of the project. Operational and maintenance costs of the turbines haveincreased manifold due to plugging of the under-sluices which has resulted inthe reservoir filling with sediments. Further, the project's primary purpose of providing morning and evening peak generation support to the national electricity grid has been completely lost due to plugging of the under-sluice gates. Due to undue objections, this hydroelectric project is even failing to serve the purpose of energy transition required for climate change adaptation.
Professional ‘Handcuff’ of Engineers
Design and construction engineers of Salal Dam were professionally ‘handcuffed’ and prevented from using standard sediment management techniques as per provisions of the Treaty. This resulted in the reservoir silting up almost to the top of the dam within a few years of the project’s commissioning.
Currently, the NHPC, the owner of this project, hasundertaken large-scale dredging operations to remove millions of tonnes of sediments. Despite significant expenditure aimed at keeping the project operational in the long run, these efforts are unsustainable, as the recurring costs of such operations are untenable.
Sedimentation up to the full reservoir level of the dam has resulted in silt being deposited above the full reservoir level in the initial reaches. A faulty design, imposed by Pakistan’s refusal to honour provisions of sound and economical design with satisfactory operation of the Project under the Treatyand the forcing of India to plug the under-sluices has even caused sediments to enter the fields of the farmers along the riverbanks. In some cases, sediments haveentered the homes of residents in the upper reaches of the reservoir, forcing them to abandon their houses and relocate.
Neutral Expert on Baglihar Dam
Professor R. Lafitte, a Swiss Engineer at the Federal Institute of Technology, a Neutral Expert appointed for the Baglihar Project has stated: “It appears that the Treaty is not well developed as far [as] the provisions on sediment transport. This is not a criticism. The Treaty reflects the status of the technology on reservoir sedimentation in [the] 1950s”.
Figure 1: Salal Dam filled with sediments and vegetation but no water
Flawed Provisions of the Treaty
The Treaty also had a basic flaw in its engineering perspective. Regarding the Western rivers, namely the Indus, Jhelum and Chenab, India has been allowed to construct hydroelectric projects with limited storage capacity, defined under the Treaty.
These rivers are flowing through the Himalayas with a very steep gradient and carry a very high annual sediment load. For example, the river Chenab at Salal dam has an annual sediment load of about 32 million cubic meters. Despite such high sediment load in these rivers, the Treaty even stipulates provision of an ungated spillway as detailed below. This clearly shows that the Treaty’s provisions were not linked to the ground realities.
Article III (2) (d), Annex D, Para 8(e) statesthat “If the conditions at the site of a Plant make a gated spillway necessary, the bottom level of the gates in normal closed position shall be located at the highest level consistent with sound and economical design and satisfactory construction and operation of the works.”
The Treaty is so biased, skewed and unsustainable that it limits expansion of irrigation facilities for cultivated land in the Union Territories of J&K and Ladakh. It contains provisions that restrict storage capacity for hydroelectric projects in India and restrict all hydropower plants on the Western rivers in India to be in the run-of-the-river category.
According to the Treaty, initial filling of the reservoirs on the Indus, Jhelum and Chenab is restricted from 21 July to 31 August of the year. Consequently, if a project is completed on 1 September of a year, it must wait almost eleven months to begin initial filling operations of the reservoir. Similarly for the operation and maintenance of the power plants under the Treaty, it has the following provisions:
Volume of water received in the river upstream of the plant, during any consecutive days, shall be delivered in the river below the plant within 7 days periods. In 24 hours within 7days period, volume delivered into the river below the plant shall be not less than 30% and not more than 130% of the volume received above the plant during the same 24 hours.
The Treaty instead of advocating the construction of safe and sustainable dams according to modern engineering practices, restricts India to construct a ‘dead’ concrete wall (dam) on the sediment-laden Himalayan rivers. This results in filling of the reservoir within a few years, almost negating the basic purpose for which these dams for generation of hydroelectric power are constructed.
Pakistan’s Double Standard
A number of major hydroelectric projects like Diamer Basha (4500 MW) and Dasu (4320 MW) located on the river Indus and in the Upper Kohistan District of Khyber Pakhtunkhwa (KP) province of Pakistan respectively; and Mahl (640 MW) located on the river Jhelum in PoK are under construction. Patrind (147 MW) and Karot Hydroelectric Project (720 MW) both located in the PoK and the bordering districts of Pakistan, have been commissioned in the year 2022 and 2017 respectively.
All these projects provide for sediment management through hydraulic sluicing via low-level under-sluices or desander arrangements, utilising modern engineering practices. In none of these projects, technological knowhow of the 1950s is being used. It is, therefore, unsustainable to force India to use the technological know-how of the 1950s, in sediment laden rivers of the Himalayas, as per wrong interpretation of the Treaty, by ignoring the basic principle of ‘sound and economical design and satisfactory construction and operation of works.’
Conscious of Engineering Professionals Constructing Dams
In the present-day environment, dams with steep gradients filled with sediments from the Himalayan rivers do not exist anywhere else in the world. It is also a fact that no upper riparian state has been subjected to such draconian provisions regarding the construction of unsustainable dams, including numerous restrictions on their operation and maintenance as applied in the IWT.
In order to make the Salal Dam sustainable in terms of sediment management, the under-sluice gates provided in this dam should be opened. Such a practice has been adopted in many existing dams throughout the world.
(Exclusive to NatStrat)
