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On the possibility of avoiding the transition reducing water withdrawal

Posted by kelman on 07 Oct 2015 at 10:49 GMT

In my earlier comment, I disagreed with the proposition that reducing water withdraw from the reservoirs of the Cantareira system would alter significantly the amount of water in the catchment (C). Therefore, a transition to a lower efficiency state, even if such phenomenon existed, would not result from a faulty operation rule. The authors answered saying that as “the reservoir outflow is of the same magnitude of the other two main natural flows in the Cantareira catchment, … it is reasonable that the reservoir outflows participate in an important way in the water balance in this system, and more importantly so the lower the rainfall. Hence not reducing water withdrawal before the transition contributed to its unfolding”. I agree that the reservoir outflow participate in an important way in the water balance of the reservoir system. However, this doesn´t mean that the reservoir outflow is relevant in the water balance of the catchment. This remains to be proved.

Competing interests declared: I am professor of Water Resources and Hydrology at the Federal University of Rio de Janeiro and president of Sabesp