Estimativa da receita líquida e empregos com uso da água otimizado de um reservatório no semiárido paraibano.

Abstract

This is work is concerned with the estimation of optimal net profit that can be obtained from the irrigation of Condado's cropland located downstream the Engenheiro Arcoverde reservoir. This reservoir has a capacity of 35 hm3, supplies 36.000 m3/month of water to Condado and Malta towns and is part of the Medio Piranhas river basin, which is located in a semiarid region at northwest part of Paraiba state, Brazil. The Condado's irrigated cropland has an area 230 ha and 72 operating amazon wells. The analysis of this system is based on scenarios in order to estimate areas for a selected set of crops and establish operational rules for the reservoir and groundwater operation. The scenarios takes into account climate, which is characterized as mean, dry and wet, initial condition for the reservoir, operational policies, which takes into account crop patterns, irrigation systems and sources of water, and sensitivity analysis of water cost and other parameters. C1SDERGO (Curi and Curi, 1999), which stands for Cropping and Irrigation System Design with Reservoir and Groundwater Optimal Operation and is based on a recursive linear programming procedure implemented in MATLAB, is used to achieve the results. The objective functions are the maximization of the net profit or required labor. All the physical, agronomic and operational constraints, including the sustainability of the reservoir, were taken into account. The results have shown the importance of an appropriate choice of a set of crops areas and patterns and the used irrigation system within a climate framework. Special attention should be paid at the sizing of areas for lasting/perennial crops. This study also shows the importance of the use of groundwater for irrigation and the initial condition of the reservoir storage for the problem. Moreover, for this problem, the difference between the net profits achieved from the maximization of the net profit or the required labor was not so significant.