Water is one of the most important natural resources, the other being the air available freely everywhere and at each split of second. In a nutshell, the universal importance of water can be put as the biological, geo-chemical, meteorological component of the environment, indispensable for the origin, existence and perpetuation of the Mother Earth and the biota inhabiting it. Hence, there is an immense demand for this unique renewable single chemical compound. It is a boon that water constitutes more than three fourths of the area of the earth and hence, it is designated, appropriately, as „watery planet‟ or „blue planet‟. Of the total water resources of the earth, the un-utilizable component accounts for more than 99%, this includes 97.2% of oceanic waters, 2.15% of glaciers and icecaps and 0.3% of UN utilizable groundwater. In fact, comparatively, a trivial quantity of less than 0.4%, including 0.3% of usable groundwater and even less percentage surface waters, is available for direct consumption. Thus, the utilizable surface waters constitute a very meagre percentage in the total global water resources. Hence, proper planning is essential for judicious utilization of this precious commodity for striking an appropriate balance between demand and availability, and availability and utilization at the global, regional and local levels for the sustainability of their ecosystems. The universal fact that land can never be physically transferred, which annotates the present context as, from water surplus region to water deficient region; whereas water can and has to be transferred to form its surplus region to deficit region subjected to its demand in the latter. This is the very concept of linking of rivers. Water status of the region whether it is water –surplus, water- sufficient, water – deficit constitutes water budget of the region. This is the result in its turn of many dynamic factors, environmental, economic, social and political (?). All these issues are discussed in the present review. * The concept of inter-basin transfer of water The concept of linking of rivers or inter-basin transfer of water is essentially based on the availability of surplus of water in the donor river especially at the point of diversion to the deficit river basin. The surplus or deficit in a basin is determined on the basis of availability at 75% dependability, import, export, and existing and future needs. A river basin is said to be reasonably in surplus of water, if the surplus water is available after meeting the irrigation needs of at least 60% of the cultivable area in the basin. Only this water from such a basin can be diverted to deficit basins. In the recipient/deficit river basin, it is proposed that, at least, 30% of the cultivable area is covered under irrigation. This is one of the most effective managements of surface water resources, as according to protagonists, it is an economically viable, technically feasible and environmentally sound and viewed as the future main stay for the sustainable development of any region confronting water deficit. On this basis, The National Water Development Authority (NWDA) after a thorough study indicated that Himalayan Rivers, especially, Brahmaputra and Ganga have exceedingly surplus quantum of water and hence, proposed transfer of water from these surplus basins to deficit basins in peninsular region (Vidyasagar Rao 2003; Reddy 2003). After assessing the technical and environmental aspects of the project, the people‟s perceptions and politician‟s willingness have to be assessed, more so the later, if the surplus river basin and deficit river basin are under two opposition parties. * Historical aspects Linking of canals is not a new concept, but has been in practice since times immemorial. Human beings started diversion of water from local resources ever since, they started agriculture, by construction of earthen “anicuts” across local streams. The “grand anicuts” of the 2nd century over the river Cauvery, recorded to be functioning till mid-19th century providing irrigation to 25,000 hectares resisting the impact of floods for 1600 long years, was the earliest known major diversion undertaken in India. Since historical times irrigation canals were developed by Cholas, Pandyas, and rulers of Vizianagarm and Kakatiyas for diverting the waters from Cauvery, Tungbadhra and Vaigai. The western Yamuna Canal and Agra Canal were built during the Mughal reign. The British rulers in India proposed to link Calcutta, when it was the capital, with Karachi and Madras through a link canal combining all the rivers in the peninsula. Later they did not pursue the matter further, probably because the capital was shifted, the expenditure was huge, and their interests were probably more vested than rested on the welfare of India. Sir Arthur Cotton, the pioneer of modern irrigation, constructed anicuts over the rivers Krishna and Godavari for diversion of the waters. The present Telugu Ganga project supplying Krishna river waters to Chennai city, Yeleru reservoir water in East Godavari district to Visakhapatnam Steel Plant, Periyar – Vaigai Buckingham Canal in Tamil Nadu, Nagarjuna Sagar Right Bank Canal and Rajasthan Canal are being successfully implemented. Experts are projecting life endangering statistics of impending severe water shortage. This crisis must not be allowed to occur. A satisfactory performance of these projects augurs well for undertaking more such inter-basin water transfers at national level.
Posted on: Tue, 16 Dec 2014 08:16:11 +0000
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