Otimização da operação de múltiplos reservatórios em paralelo para usos e objetivos múltiplos.

Abstract

The aim of this work is to study the behavior of a system of three reservoirs, Tapacura, Goita and Varzea do Una, which are connected in parallel and designed for multiple uses. They are part of the Capibaribe river basin, PE, located in the northeast region of Brazil. The problem herein was to analyze and design optimal operating policies for both the reservoirs water releases and irrigation sites nearby in order to maximize the net profit, as well as the required labor, of irrigation and fishing activities. Several scenarios based on different reservoirs initial conditions, system setup, water demands and climate situations, which were characterized as average, dry and wet, were studied. The ORNAP software (Curi & Curi, 1999), which is based on a nonlinear programming model and works on a monthly base, was used to achieve optimal solutions for each scenario of the problem. All the physical (reservoirs, spillways, channels, outlets, pumps and water treatment station capacites and relationships), environmental (floods and environmental water discharges), legal, operational (flood control, human water demands and sustainabilities of the reservoirs) and agronomic (land use, cropping and irrigation patterns and managerial limitations) constraints were taken into account. The constraints were satisfied and the human water demands were garanteed for all the achieved results. The results have show that the best economic performance is obtained when the reservoirs withdraws for the human water demands are not regulated, that is, when the program is allowed to choose the best monthly reservoirs water withdraws to couple with the human demands. Moreover, the results are dependent upon the reservoirs initial storages while considering the reservoirs sustainabilities. All the tests have also shown that the ORNAP is suitable and applicable to analyze this kind of problems.