As águas subterrâneas do perímetro irrigado Curu-Pentecoste (picp), Ceará: geometria aquífera, qualidade e disponibilidade hídrica à irrigação

Abstract

Ceará, and most of the northeastern states, went through six consecutive years of drought (2012-2017), classified as the worst of the last 50 years, which caused great losses in the northeastern agricultural sector, both in rainfed agriculture and in irrigated, since the water stored in the dams is not sufficient for this purpose. The Curu-Pentecoste Irrigated Perimeter, area of this research, is part of the Curu River Basin is located in Ceará, in the Uruburetama microregion (Vale do Rio Curu), an area considered to be of economic influence, located 90 km from Fortaleza. The area delimited for this research (18 km²) is located in the central part of the perimeter and corresponds to 36% of the perimeter area (50 km²), representing the irrigation nuclei C, D and F. The research seeks to characterize the quanti-qualitatively the groundwater of the PICP with respect to the Allogic Hydrogeological Domain for the purpose of using these waters for irrigation, and with that, propose a methodology for that purpose. For this, a bibliographic survey of the effect of drought on the agricultural production of the Perimeter was made, registration of the wells and mapping of the PICP Alluvial Aquifer, selecting those present in the agricultural plots of the C, D and F nuclei. monitoring of variations in static levels, measurements of physical-chemical parameters of the water and geophysical survey by electroresistance. In the interpretation of the data, SPSS Statistics, Piper and USSL diagrams were used. The technique was also used in factor analysis, associated with multivariate cluster analysis, aiming to support qualitative management. It was concluded that the irrigated perimeters of Ceará are vulnerable to the effects of drought, given that they suffered a sharp drop in production since the first years of drought, where the smallest perimeters reached a total collapse in 2014. The alluvial waters of the PICP have adequate quality for use in the irrigation of most of the crops already implanted. The alluvial aquifer in the region has an average saturated thickness of 7 m and a width of 600 m, presenting a sufficient water reserve to maintain agricultural crops during the dry season. Following the presented methodological steps, it is possible to evaluate the water potential for irrigation of the analyzed Alluvial Aquifer.