Comportamento da relação evaporação-vertimento-liberação de água pelos reservatórios sob diferentes regras de operação

Abstract

Semi-arid regions are critic for water supply due to the deficit in water balance, generated by high evaporation rates and insufficient precipitation, that damage superficial reservoirs efficiency. On the regularization process of a reservoir three hydrological fluxes are fundamental for understanding the inflows and exit flows of water: evaporated outflow (E), spill outflow (S) and yield outflow (Y). In this region, the E and S losses are, many times, of high magnitude, affecting the third tranche (Y). The study of the ESY relation with the physics parameters associated at the reservoir regularization process could lead a reduction of its losses and to increase the water supply associated, on periods of high inflow, for example. Then, this work made the study of the ESY relation influence on the 50 reservoirs operating efficiency distributed on Rio Grande do Norte (RN) and Paraíba (PB) states, combined with the reservoirs characteristics variable analysis. As main result, the study indicate that higher restrictions of water use could increase the evaporation losses and, possibly, by spill. For that matter, not always the water harvesting on flood periods for use on drought periods cause waited benefit for a reservoir efficiency, which was observed losses as the restriction was increased. On average, the reservoirs were below of the 90% efficiency for meeting demands, for the whole operation period.