State faces 11% water deficit, stares at acute crisis: study

Julie Mariappan, in her article (Times of India Chennai, April 6, 2013) reports that Tamil Nadu is facing a deficit of 11%. While the current total water demand in the state, for domestic, irrigation, livestock and industrial needs, is 1,867.85 TMCFT (thousand million cubic feet) per year, the total availability, from all resources, is only 1,681.78 TMCFT. This deficit will rise to 17% by 2045, said the report, jointly prepared by several central and state governmental agencies, including Tamil Nadu public works department and Central Water Commission. Water experts say a 11% deficit at present means that the state is set for an acute water crisis in the coming years, and one will have to blame the situation on the lack of serious conservation efforts. Tamil Nadu, which had three reservoirs, in the pre independent era, has added 82 reservoirs in the last six decades and boasts of 39,200 tanks now. At least 17, 879 of them, big and small, are on the coastal belt, and their status is either ‘good’ or ‘normal’. But an alarming 80% of overflows from rivers is wasted, said the report based on the study on ‘Effective utilization of Northeast Monsoon’. The report has proposed Rs.13, 560 crore for works in the next decade to rectify the system. Above to 130 TMCFT of water flows into the sea from at least 10 rivers, including the Cauvery, it said. Compare this to Chennai’s drinking water needs – one TMCFT every month. Sedimentation has reduced the capacity of several reservoirs between 2% and 59%. Built in 1934, Mettur reservoir, the life line of Cauvery Delta, loses 11 million cubic metres of storage capacity a year due to sedimentation. The water tanks lose 40 – 50 million cubic meters of storage capacity every year. The report emphasized the need for consistent efforts to desilt water bodies. The silt can be used either for construction, agriculture or river restoration, it said. “Thanks to the new reservoirs and better management of water tanks in parts of the state either by PWD or local bodies, the defect could be managed over the years. But the demand is shooting up every year”, said a water manager. The report suggested it would be prudent to link the rivers within the state by short canals to divert the occasional flood s flows to the adjoining basins. The state often witnesses a situation in which one river is in spate and other is bone dry. The state will now be compelled to augment the capacity of existing storage structures in coastal regions, construct check dams and a new reservoirs and link rivers, wherever possible, as suggested by the report. “Unless this is done, the future looks pretty bleak. With a majority of the rivers being interstate, dependence on neighboring states should end”, a member of the study team said. The good news that the 41– year data shows there is no dramatic change in the trend in the onset of the North – east Monsoon.