The tracing technique has been recently used in karstified Zagros structural belt in northern Iran. A tracer study (uranine injection) was conducted in Jurassic limestone of the Poshte-Naz area in the Alborz belt to evaluate aquifer parameters and hydraulic relations between a large (about 100 m in diameter) sinkhole and springs. A main goal of the project was to find out the source of turbidity of the Emarate drinking water supply spring (SP4) in rainy seasons. Eight springs, three wells and the Neka River were selected for monitoring and totally 989 samples in 107 days were collected. In order to select reliable sampling stations, hydrochemical analysis of major ions was carried out and for better interpretation of concentration-time curve, spring discharge was also measured. The results of the tracing by sampling water indicated only a hydraulic connection between the injection point and the Sange-Nou spring (SP8) and, whereas the charcoal bags analysis revealed tracer exits also from spring SP1, SP3, SP4, SP5, SP8, in wells W1 and W2, and in the Neka River. This paper discuses concentration/time curves from charcoal bags for qualitative analysis and tracer exit curves for quantitative analysis.