MEDIDAS DE 18O E HIDROQUÍMICA DE ÁGUAS SUPERFICIAIS E SUBTERRÂNEAS NO ESTUDO DA INTERAÇÃO RIO – AQÜÍFERO, NA REGIÃO DE LIMOEIRO DO NORTE – BAIXO JAGUARIBE – CE

Abstract

For an investigation in losses of river flow of Jaguaribe river, in the region of Limoeiro do Norte, surfaceand groundwater samples were taken, in dry and rainy seasons, during a period of 2 years. Oxygen-18 and hydrochemicalanalyses were performed to avaluate the origin of aquifer recharge and river/aquifer interaction. Results show pronounceddifferences in 18O between Jaguaribe river (mean: +1.6) and the Jandaíra aquifer (mean:-2.4), strong seasonal variations in18O in the river water, positive values for this parameter in some wells, indicating the influence of the river, and chemicalhomogeneity of Jaguaribe river water and those from the majority of wells. A general analysis of the data indicates aconstant recharge to the alluvial aquifer though river water, however more pronounced during dry seasons.