Method for Measuring High Tracer Concentrations in River Mixing Studies

Tracer experiments are a well-established technique for investigating mixing processes in rivers.A critical aspect of these experiments is ensuring the use of an appropriate amount of fluorescent tracer so that its concentration can be accurately measured with the available equipment.However, determining the optimal amount of tracer beforehand is often challenging.Furthermore, tracer concentrations can vary significantly during mixing processes, making accurate measurements at cross-sections near the injection point, as well as at more distant river cross-sections, particularly difficult.To overcome these challenges, a method was developed to retrieve valuable data when tracer concentrations exceed the measurement capabilities of the equipment.This approach utilizes the optical properties of the tracer solution in the presence of scattering particles within the fluid.By combining turbidity and fluorescence intensity readings, the method enables calibration of the turbidity-concentration relationship.This allows for the determination of tracer concentrations even when the fluorescence intensity-concentration relationship exceeds the linear regime.