Incorporating macro climate indices in flood prevention studies for the Brazilian hydropower system

Hydropower reservoirs with volumes capable of serving for river regulation provide a series of other benefits, for example, flood control. Since the 1970s, in the Brazilian electricity sector, electricity generation and flood control have been the two main shared functions of reservoirs. Operation for power generation involves aiming to keep the reservoirs full, storing water during periods of favourable hydrology, to use it during less favourable hydrological periods. On the other hand, the flood control requires keeping part of the reservoir volume empty (a so-called ‘waiting volume’) to protect the downstream valley from extreme outflows. One way to optimize the use of the reservoirs is to consider, during the operation planning, information that can better predict the behaviour of the next rainy period. This paper presents a review of the consideration of macroclimatic indices (El Niño - Southern Oscillation) in flood prevention studies in the context of operation planning for the Brazilian hydropower system.