Mounting Antagonism towards Big Dams Ashok K Mitra 3 D Dhawan (May 20) has attempted to put he issues relating to large and medium forage route to irrigation development in proper perspective. While he himself is not onvinced with the questions raised by the environmentalists, soil conservationists, social and natural scientists against the role of major irrigation works based on big lams, he has appealed to the irrigation plan- iers to engage in an open dialogue and liscussion with their critics. His own defence against the grounds on which the idea of big lams is being questioned, however, does not ippear to be too convincing. To begin with, insider first the environmental angle. While ie accepts that the forest cover to be lost by single dam like Narmada Sagar can be un- iuly high it is no solace to learn from him hat damage to forest is much higher on ac- count of illegal felling, unauthorised ploughing of forest lands, authorised allotment of forest land do dam oustees, and increased pressure from the grazier. Besides, or all we know, damage to forest because if all these factors may be the backlash of brest cover lost and people ousted for the instruetion of big dams. In any case to minimise such losses his suggestion is to increase the storage height. But, it should of be overlooked that reducing the rcser- oir size is not merely a technical issue; its eonomic implications in terms of costs and enefits will have to be worked out in order examine if the economic feasibility is Aversely affected. A more general point, hpwever, is that loss of forest cover cannot counted only in terms of felled trees, it as to be seen in its entirety in terms of estroying the whole eco-system which in the ong run may adversely affect the availability water in the reservoir through siltation and deficient rainfall in the catchment area, trc all these externalities fully internalised in listifying the projects on economic grounds? Similarly, the problem of land degrada- |on by waterlogging and soil salinity within the canal commands served by big reservoirs, suggests, can be effectively checked with id equate provision of drainage or the use If drip or sprinkler modes of water use as case may be. But, the cost of drainage irk is no different from that of the canal twork itself and hence because of paucity investment fund this work is missing from ir major canal network. Yet the benefit is climated on the entire potential created sregarding the fact that owing to lack of ainage gradually in the long run more and ore land in the canal command would get graded. Has this been properly accounted in cost benefit analysis to justify the object on economic grounds? Secondly, consider the technical issue lated to seismic disturbances owing to im- wnding huge mass of water as in the case Tehri dam in Garhwal which may cause earthquake of severe intensity leading to ter disaster. Again, is the safety factor sug- sted by Dhawan considered in full, if so, is the increased cost involved in ensuring such safety economically justify constructing such dams? Tehri dam's case in this respect has been very clearly brought out by Paranjpye which merits very serious consideration Thirdly, the sociological angle of rehabilitation of dam oustees, one of the most sensitive issues, cannot be settled by earmarking a lump sum amount as compensation to be paid as suggested by Dhawan. The nature of compensation to be paid, the manner in which it is to be paid, the period over which it is to be paid and whether it covers the annual income earned by the oustees have to be examined in detail. The planners and the officials are most secretive about these details. One wonders, if the compensation is arrived at in this manner how far would the project be viable in terms of benefit-cost ratio.
