Identification of karst springs recharge areas using qualitative tracing tests; Lajeado - Bombas; Iporanga; São Paulo.

Abstract

Qualitative tracing tests with rhodamine FWT dye were employed to identify the structure of underground drainage and to define recharge areas of karst springs in a limestone plateau located in the rain forests of southeastern Brazil. A method is proposed for the interpretation of qualitative tests based on natural background fluorescence obtained with charcoal detectors. The results of connection tests between sinkholes and springs showed that at least three karst conduit networks are responsible for plateau drainage: one of convergent structure (Areias), one of divergent structure (Córrego Fundo) and one whose structure has not yet been determined (Bombas). The results show that the detection of hydrologic connections with rhodamine FWT and activated charcoal is viable in the karst landscapes located in rain forests of southeast Brazil.