Irrigation is the single most important factor in our achieving a fair measure of self-sufficiency in food production. In 1947, the total irrigated area was a little over 20 Mha, which in the last decade became 47 Mha. Nearly 25 percent of the cultivated area is irrigated, which is 1/5th of the total irrigated area in any country of the world.
You know that storage of water by building large dams is regarded by irrigation engineers as a crucial component of water management system. In India, too, such a high level of irrigation potential was achieved through building of large dams.
Through the benefits of these big river valley projects were three-fold, namely, (a) generation of hydro-electricity, (b) irrigation and flood control, and (c) industrial and municipal water supply; the adverse ecological implications are manifold: deforestation, landslides, sedimentation, soil erosion, seismic activity, displacement of inhabitants and epidemic eruption of water-borne diseases are only a few of them. It is a paradox, however, that as a result of installation of major river valley projects, the total flood prone area of India instead of decreasing has actually doubled from 20 Mha to 40 Mha in the last decade.
Since Independence, more than 700 dams have been constructed. If Government programmes go ahead as scheduled, there will be hardly any free flowing river left in the country by the time the implementation of these programmes is achieved.
One alternative to the big river valley projects is to construct smaller reservoirs of water and mini-hydel units for irrigation, power and city supply. This will help avoid large-scale tampering with ecological balance. Smaller units can be built, maintained and operated by local communities. The adverse side effects of these units would, certainly, be lesser. There would also be reduced chances of accidents, to which the major river valley projects are very prone. The size of these mini-projects should be such that the perennial flow of river remains undisturbed.