India is gifted with a bouquet of 20 perennial and non-perennial river systems, with several tributaries. Our rivers, mostly originating from the Himalayas, the Chhotanagpur Plateau and the Western Ghats, receive a significant run-off, from glaciers and precipitation, accumulating an average annual flow of 1,953km3, while replenishing groundwater resources of around 432km3. This enables the formation of a perennial utilisable water resource, one expressed in surface water (690km3) and ground water (396km3). In particular, Himalayan snow and ice melt offers a significant boon, with water yield in such river basins nearly double that of the peninsular rivers. Groundwater, wherever available, remains a significant source of water, particularly for domestic consumption, contributing 80 per cent of the household requirement and over half of the irrigation requirement.
India’s rivers undergo a series of changes across their route and through seasons—turning into a slack pool during winter; raging as torrents during the monsoon, awing us with its destructive potential. While rivers are often described in a feminine sense, as nadi, beautifully coursing across Jambudvip, as dividers of solid land, they can also be dangerous. After all, the Ganga descended from heaven, bringing with it fertile soil for good crops, but also destruction in its wake. Sustainably managing such mercurial rivers to meet the challenges of rural India can hence be a hard task.
To combat this risk, and to provide irrigation to millions of marginal farmers, modern India has sought to build dams. Starting from 1947, when there were just 300 large dams across India, the government has built around 4,900, with the majority built between 1971 and 1989. The primary purpose of these dams has been to further irrigation, in addition to control floods, ensure water supply and generate hydroelectricity. Large dams, termed as “temples of modern India” by Jawaharlal Nehru in 1955, were encouraged post-independence to jumpstart industrialisation and establish a scientific outlook.
However, this love affair with big dams didn’t last long. As Nehru said, within three years of those famous words, on ‘Social Aspects of Small and Big Projects’: “For some time past, however, I have been beginning to think that we are suffering from what we may call, ‘disease of gigantism’.” The economic gains associated with dams can accrue to different population segments. Most of India’s irrigation dams are actually embankments in nature, with a wall built across a valley to impound water, creating a reservoir upstream and in many cases, displacing villagers and livestock; a large dam can easily displace up to 10 per cent of an average Indian district. While dams can provide large productivity benefits in aggregate, particularly for irrigation and recharging the water table, they also incur significant social costs, with the economic benefits accruing disproportionately to people living in the command areas; the average dam displaces 31,340 people, while submerging 8,748 hectares; scheduled tribes typically are amongst those most affected, constituting 47 per cent of those displaced. For those whose agricultural and grazing land is flooded, the government’s compensation is often significantly delayed and a pittance at that; such compensation is typically insufficient for replacing lost land by an equivalent land with similar quality elsewhere.
Cost benefit analysis studies have highlighted that dams are mostly marginally effective, offering a rise in agricultural productivity of just 9 per cent (the World Commission of Dams estimates a 10 per cent average). A dam can increase net irrigated area by 0.7 per cent in its own district and around one per cent downstream, when accounting for displaced agricultural areas and a ban on upstream canals to maintain flow downstream. A Planning Commission estimate highlighted that the development cost per hectare of dam irrigation was Rs 16,129 in 1985 (incorporating capital and maintenance costs, and Rs 18,807 per hectare if fertiliser costs are added in). As highlighted in E. Duflo & R. Pande’s seminal analysis (2005), comparing this with a purported present discount value of net increase in irrigated area of Rs 13,686 and an overall lower irrigation cost (vs groundwater irrigation), gives a marginal net present value; a return of just 1 per cent. In addition, dams can induce waterlogging and raise soil salinity—by 1991, around 2.46 million hectares of land associated with the command area of dams was suffering from waterlogging, while 3.30 million hectares was suffering from salinity; 10 per cent of the total area actually irrigated back then. Maharashtra has over 40 per cent of India’s large dams; even so, over 82 per cent of the state continues to be rainfed; Maharashtra pushed large dams, not irrigation (Devendra Fadvanis, July 21, 2015).
In comparison, other forms of water harvesting (eg: dykes, groundwater) can prove to be more cost-effective, if given due attention. Maharashtra has over 70,000 small irrigation projects (each with a potential to irrigate at least 250 hectares), costing over Rs 4,600 crore, but just 12 per cent of their total irrigation potential is actually utilised (2 lakh hectares of 16.25 lakh hectares). While such small bunds and percolation tanks could make a significant difference to drought stricken villages, most of them have fallen into disrepair, choking with silt or simply vandalised. They have simply been built and forgotten, with no manpower or budget allocated for maintenance and management.
The unfortunate impact of this spate of dam construction on river flow is slowly coming to light. The Chambal is one of the few pristine rivers still remaining, offering a pristine habitat to the endangered Gangetic river dolphin, the critically endangered gharial, and the red-crowned roof turtle, along with host of birds and fishes. It offers a critical linkage in a fragmented forest landscape, providing a vital corridor to Ranthambore, Kuno-Palpur, Madhav, Darrah-Mukundra and Keladevi. However, since independence, its isolation was disrupted, with a cluster of dams built to provide solace to arid districts in Madhya Pradesh and Rajasthan. Over six major irrigation projects, 12 medium and 134 minor projects came up across its basin, leading to a steep decline in its pre-monsoon water flow (Only 10 per cent-15 per cent of the Chambal’s length now has the minimum depth required for gharial and dolphins to survive during summer). The Chambal, a serene and yet isolated river, cursed in Hindu mythology, has been disrupted, with its famed ravines (where the dacoits used to roam) being flattened by sand mining and industrial water usage reducing water levels. While the Central Water Commission issued a guideline in 1992 outlining that a dammed river must contain a minimum flow of an average of 10 days in its natural state, the Chambal has been stripped of its natural sheen. This has had consequences, even for agriculture—the average quantity of Chambal water used for irrigation in Rajasthan and Madhya Pradesh from the Gandhi Sagar dam and the Kota Barrage declined by 22.6 per cent and 41.4 per cent respectively, between 1990 and 2007; all while industrial usage increased by over 300 per cent. Villages are increasingly running short of water in irrigation canals—at Bhakto ka Ghat, near Kherli village, in Rajasthan, the Chambal’s depth is usually just knee deep during the winter months; nonagenarians in the village recall the days when the river could only be crossed on boats. The overall flow in the Chambal has been declining by 3.4 per cent annually since the 1990s, with the gharials losing over half their existing habitat, leading to potential starvation. This river, once cursed, is likely to remain so.