Critérios para concessão de outorga e eficiência do uso dos recursos hídricos pela irrigação

Abstract

When considering the qualitative and quantitative aspects of water resources, it should be noted that in a situation of plenty of water, it can be treated as a free good, without economic value. However, with the increased demand for the resource, which then passes to be scarce, conflicts between uses and users may occur. Given that the region in which Ivinhema’s basin operates be of great potential for agricultural development and, with the growth of irrigated agriculture and industrial production, due to the implementation of alcohol producing industries in the region, this proposal aims to provide technical and scientific support to promote greater socio-economic and environmental development, considering the seasonality water in the granting concession process, aiming the better use of water resources, and quantification and analysis the efficiency of water use for irrigation in the basin. Monthly, quarterly, four seasonal and semiannual seasonal periods were compared to annual period, for calculating the flow reference Q7,10 and Q95 in order to quantify the relative differences in water availability between the reference flow rates used for purposes of granting use of water in Brazil. To analyze the efficiency of center pivot irrigation was used the methodology proposed by Merriam and Keller (1978) and later were obtained the CUC and CUD values, that rated the uniformity of water application. The quantification of flow demanded by irrigation and analysis of the efficiency of use of water resources in the agricultural sector were obtained according to the methodology proposed by Pruski et al. (2007), and Keller and Bliesner (1990), respectively. Based on the results, it was found that: a) the best criteria for awarding grants is the monthly Q7,10, although more restrictive, it allows higher flow rates of grant in periods when there is excess of water, and lower values in the months of lower water availability; b) in all assessed properties was found that the blades of water are applied below recommended, featuring deficit irrigation and mismanagement of irrigation system.