The river at your door

To Raju, Shaw and like minded experts, “A river basin, as is evident from the definition, is a natural division that has physical existence (unlike political and administrative boundaries). Furthermore, river basins occupy the apex of a hierarchy of natural subdivisions like sub-basins, watersheds and micro-watersheds. This is perhaps the most powerful rationale for the introduction of management of water resources through a river basin approach.” Now should water policies be formed at the agro-climatic or river basin level? If and when we take water policy seriously, this will become important.

In 1986, when I was minister of planning, I had set up the National Commission for Integrated Water Resources Development. Raju and Shaw note that it categorised India into 24 important basins. Of these, 12 are designated as major basins (basins with areas in excess of 20,000 sq km). On the river basin map of India it is evident that the Ganga-Brahmaputra-Meghna sub-basin is the largest river basin in the country, with an area of 1.097 million sq km. The basins of the east coast are significantly bigger than those of the west coast. Also, the rivers of peninsular India are non-perennial; consequently rivers cannot be depended upon as perennial sources of irrigation water. Therefore, alternative sources of irrigation like tanks are prevalent in peninsular India. The commission, however, recognised that for different aspects of policy making, states, agro-climatic regions, districts and micro-watersheds could be units.

While not strictly so, water can be treated as a renewable resource. Fresh water supply can be determined in an agro-climatic regime in a defined time period. Water flows do not follow administrative or political boundaries. Aquifiers are confined by geo-physical and not political and administrative features. Climate also determines the demand for water, including evaporative demand. Seasonal rainfall cycles can be very different across countries. Aquifiers can show the amount of water that is really available. Recent interesting work includes sensitivity of estimated resource flows of water available with integration of surface flows with local small storage projects. I had reported in 2000 an augmentation to the extent of 14 per cent of estimated water availability in the Narmada system with such integration. It is interesting that the Shedhi branch of the Mahi system was planned on the basis that there are no tanks in the system.

More precise assessments can in many cases make the difference between scarcity and conflict, on the one hand, and the possibilities of a judicious management strategy on the other. The argument here is that conceptually the measurement of water availability has to be in the context of a physical system and therefore in the ecological domain. This would be a strong argument for integrating such work with the long tradition of work on agro-economic zoning. The categories behind agro-economic zoning, of soil or land type, water and climate (which includes rainfall), are important. There is really no dichotomy between agro-climatic classifications and ecological analysis. The mighty river and the pond next door have to go together. This is important for ideas of transferring water across huge areas.