[en] In this study, it is aimed to simulate a radioactive material dispersion in an open channel by a releasing scenario. It was formed for central releasing position in an open channel which can be occurred by accidentally or intentionally. Furthermore, flow is assumed as laminar. Experiments were observed in concept of radiotracer technique. Na-24 was chosen as a radionuclide in a common compound which can be reached easily. For this purpose, an open channel was constructed in the laboratory and the experiments for the observing of the laminar current. Releasing of the radionuclide was simulated instantaneously. Experiments were carried out for nine different detector places over the open channel by using NaI scintillation detector and multichannel analyser system. Dispersion of the radionuclide in the channel was observed continuously until taking nearly same count rates from the detectors. The experiments were also realized by the optic-visual technique with the methylen-blue (C₁6H₁7N₃S) in the same time. The dye technique was used for visualization of the releasing dispersion. So, the experiments were observed with two different techniques together. As the result of the experiments, for the laminar releasing dispersion in the open channel was observed and warning time and affected distance were informed as largely. The results were evaluated with the comparison of the two techniques which are fairly appropriate each other