At the outset it would perhaps be useful to demarcate two different terms that this article will be using: The first is inter-basin water transfer/river linking (in the Indian context), which refers to channeling water from one river basin to another by connecting them through a network of canals, barrages etc. The second is water diversion, which is simply the extraction of water from one drainage basin to areas outside of it through canals and underground pipe networks. While the second phenomenon is not the same as the first, the consequences both these projects entail are quite similar. An examination of the latter will prove helpful to our understanding of the former as well.

Source: Business Insider. Since the inception of Soviet projects in the 1930s to divert water from the Amu and Syr Darya rivers that fed the inland Aral Sea, this once thriving ecosystem has almost entirely disappeared.

A Flawed Logic

The rationale behind the inter-basin water transfer project has been rather arithmetic. Basins are divided into ‘surplus’ and ‘deficit’ basins through a simple subtraction of the available water quantity and the usage requirement in its drainage area. Further, it is postulated that basins that are prone to flooding can be connected to those that are prone to drought, which will ‘equalise’ the water quantity between them, mitigating both floods and droughts. Counterintuitively, climate change is used to buttress this logic on the basis of the simplistic notion that “wet regions get wetter and dry regions get drier”. Hence, it is said that interlinking rivers could not be more urgent and lucrative, precisely because of climate change. 

The last notion is not borne out by the evidence at all; both ‘wet’ and ‘dry’ basins have experienced a change in rainfall patterns, water availability etc. in different directions. Climate change transforms the meteorological phenomena that interact with different geographies and biomes to produce complex changes that cannot be reduced to such maxims. 

However, even more alarming is the logic of surpluses and the related argument about flood control. Life on earth would be much easier if ecological phenomena could be understood in terms of simple arithmetic; but, for better or worse, rivers are not arithmetic. They constitute ecosystems that are not simply the sum total of the water they carry, but exhibit several geological, biological, and environmental dimensions. Hence, the very idea of a water surplus is suspect; ‘human’ need that may itself be incorrectly approximated neither captures the aquatic systems a river supports, nor the long-term phenomenon of silting that nourishes drainage basins with sediments and nutrients. Moreover, the almost commonsensical notion of the water cycle implies that water does not simply ‘get wasted’ by entering the sea.

The idea of flood-drought mitigation, too, is based on the flawed categorisation of rivers into flood- and drought-prone. This misses out on the fact that floods and droughts are often seasonal occurrences—rivers that otherwise remain dry throughout the year could also induce floods during the monsoon, but that is not enough to pigeonhole them as ‘flood-prone’. Moreover, when the floods do occur, the capacity of these ‘river links’ would fall far short of the excess water held by these rivers to make a significant contribution. Further, it is often observed that within the same drainage basin, one rivulet may be flooded while other areas still are experiencing drought. Diverting water from such basins could exacerbate droughts rather than reduce floods (I emphasise that the project is intended to be an inter-basin rather than an intra-basin transfer. While the latter encompasses a natural geomorphological process and all small-scale water diversions within a river basin, the thrust of the project is in the former direction, as illustrated in the first article of this series, to connect entirely different drainage basins).

While the above are crucial conceptual flaws with the idea of an ‘interlinking’ project itself, the potential consequences of such a project serve to reinforce some of its problems. The following sections will provide an account of these consequences through relevant global examples.

Geomorphological Infeasibility: Silting and ‘Water Lifts’

Geomorphology refers to the study of the underlying geological substance of a geography, and the surface-level physical features it affects and interacts with—in this case, rivers. One of the issues with connecting two distinct river basins through an artificial channel is that the area through which it flows will be radically altered—much of the water will seep through this drier ground, affecting the soil composition and character of surrounding areas and potentially waterlogging them. This could, in turn, increase salinity and adversely affect plant life and agriculture in the surrounding areas. 

To solve this, channels would need to be made non-porous through concrete and other material. This gives rise to the issue of silting; rivers carry not just water but a host of nutrient-rich sediments that get deposited on river banks. This silt would settle at the bottom of these canals, leading to stagnation of water over time and increasing the risk of flooding. Moreover, such a setup would not be conducive to the development of a riverine ecosystem similar to the source river.

Another important geomorphological aspect is altitude—river basins are not located at the same height and traverse complex geographies. A connecting channel would have to take this into account. While government policymakers have enthusiastically argued that gravity alone would achieve most water movement, it is difficult to see how this could be the case across 30 different projects. This would require the use of water-lifts at a large scale, which would make the project rather costly even from a purely monetary perspective. An example of this is the recently concluded Pattiseema Irrigation Lift project in Andhra Pradesh, transferring water from the Godavari basin to a canal connected to the Krishna. Apart from the serious conceptual errors underlying the project, the cost of about Rs. 1400 crore coupled with the electricity this lift uses far outweighs the benefits realised from any additional irrigation capacity (the final article in the series will be analysing this project at length).

Impact on Aquatic Life: the Case of Canada

The logical fallacy that ‘river = water’ also bypasses the fact that often, the nature of water in different river systems—its chemical, nutrient, and microbial composition, the sediments it carries, the fish and plant species it supports—is highly varied. Connecting two distinct river systems would mean a disruption of all these aspects, which can have serious repercussions on riverine ecosystems, and destroy fisheries in both rivers.

Canada, which has a vast network of river infrastructure in its sparsely populated Northern wilderness to generate hydropower and divert water to other areas, provides some examples on this front. Several inter-basin transfer projects were rejected in Canada, like the McGregor water diversion project in the province of British Columbia in 1978, on  grounds that it could potentially transfer fish parasites from the Pacific to the Arctic drainage area. This is also why Canada has resisted attempts to overcome trans-continental drainage divides—physical features like mountain ranges that disconnect vast drainage basins from each other, the basins thereby developing divergent ecologies over millennia. An example is the opposition to continuous US efforts to connect the Missouri to the north-flowing (i.e. draining in Canada) Red River through projects like the Garrison Diversion, over fears regarding invasive species like gizzard shad and rainbow smelt. Already, extensive damming for the purpose of water diversion and hydroelectricity has decreased river flows in Canada, leading to increased water temperature and fall in fish populations, smothering fishery potential and the livelihoods of several native tribes.

Socioeconomic Ramifications

Any inter-basin transfer project is likely to require a host of infrastructural contraptions that are common to any large river infrastructure project, like reservoirs, barrages, dams etc. This invariably leads to the inundation of settled areas, and almost always with vulnerable groups dependent on the river and forest ecosystems that such projects threaten. These groups subsequently require rehabilitation and compensation. The track record of Indian governments on this front is rather dismal, to which the innumerable movements against large dams by rights groups bear testimony. 

Source: The Caravan. Protesters under the more than 30-year-old Narmada Bachao Andolan in September 2019. The recent proposal for the Par-Tapi-Narmada interlinking has exacerbated protests against the lack of community consultation, insufficient rehabilitation, and colossal environmental damage.

However, another facet often ignored in water policy due to a ‘terrestrial bias’, is that of coastal communities. The adverse effects touched upon in the previous sections stand compounded when it comes to coastal communities—the flawed idea of water getting wasted by draining into the sea fails to take into account the dependence of river deltas and estuaries on continued and voluminous river flow and silt deposition. These phenomena have a bearing on coastal agriculture, fisheries, and forests (especially mangroves like the Sunderbans), that depend in large part upon the nutrients provided by rivers and their interactions with the sea. The fact that this aspect is not taken seriously in Indian water policy is all the more alarming, given the economic and environmental importance of river deltas all along the Eastern coastline. Already stressed due to extensive damming upstream, like the Farakka barrage on the Ganga, and devastating cyclones exacerbated by climate-change, the disruption caused by river interlinking might be the death knell for these deltas and the communities dependent on them. 

Geopolitical Issues

There is also often a geopolitical angle to large water diversion schemes. A river in the Western United States offers one of the starkest examples of this: the Colorado. It would not be an exaggeration to say that this river is the lifeline of major metropolises in California like Los Angeles, feeding several towns, cities, and farms across the West through a network of canals, aquifer pumps, and pipelines. However, this has had an almost irreversible impact on the river’s ecology and character. While most of the river flows through the US, the historically significant delta lies in Mexico. Over the past century, this once thriving delta has been reduced to a mosaic of dry river beds, rocky terrains occupied by invasive plant species, and disparate, trickling channels that do not even reach the sea anymore. The fact that the people at the receiving end of these changes are Mexican farmers has translated to disproportionately little attention to this area, consequently leading to tensions between the United States and Mexico. That such a situation could arise in India vis-a-vis Bangladesh is almost a given, a country with whom we are already mired in several issues of water diplomacy.

Alternatives: An Ideological Barrier

There are several ways one could go about solving the water woes of India that don’t involve inter-basin transfers at all. The first has already been touched upon: small-scale intra-basin transfers. Not only do these overcome some of the significant infrastructural and investment challenges posed by large-scale projects, they don’t entail an alteration of riverine ecosystems and make sure that water within a basin stays the same. They could ensure the provision of water to communities already adjacent to these rivers, which is currently not a given. Secondly, expanding rain-water harvesting, replenishing aquifers, and instituting various local-level practices for water management can go a long way in mitigating droughts. The third and perhaps most crucial mechanism consists of several ‘withdrawal’ practices; the devastation caused due to floods and the fall in water tables often doesn’t require additive measures to control floods and building more irrigation facilities, but ensuring that human activity is relocated outside vulnerable areas and changing agricultural practices to reduce pressure on limited water resources. Essentially, reducing pressure on water demand rather than simply expanding supply seems to be the more ecologically sustainable route to take.

A rather fundamental problem with the shape this debate itself takes is that river interlinking has been established as a normatively desirable activity whose feasibility is analysed thereafter. Instead, what is required is a more inductive process that operates in the other direction: looking at specific water-related issues, tapping into small-scale local solutions, prioritising non-interventionism rather than infrastructural bandaging, and only then thinking about large-scale projects. However, none of this is nearly as glamorous as a mythic ‘interlinking of rivers’—although all the more ecologically-sensitive and regenerative for it. The humbling proposition of removing river encroachments and tapping into localised solutions, thereby allowing rivers to take their own course and for ‘self-healing’ mechanisms to kick in, is what our uncertain future demands; when it comes to ‘controlling’ rivers, less is, in fact, more.

Adit Shankar is a graduate in Economics from Ashoka University, currently pursuing the Ashoka Scholar’s Programme.