FEASIBILITY OF USING A SALT TRACER DILUTION METHOD TO ESTIMATE STREAM FLOW IN SMALL MOUNTAINOUS CATCHMENTS IN THE SUMAVA MOUNTAINS
Abstrakt
Streamflow monitoring is very important in hydrological studies, especially, determining the relationship between the water stage, which is captured by a monitoring station, and discharge is still a challenge. Therefore, selecting the method to measure the discharge is vital for analyzing the above-mentioned relationship, i.e. rating curves.
In small mountainous streams, an effective and equivalently-accurate alternative to the conventional velocity-area method for developing rating curves involves the injection of a chemical tracer. .Salt dilution uses the changes in concentration caused by salt injection to estimate the streamflow. Due to the electrical conductivity of the solution, it is more feasible and easier to measure in the field than stream concentration itself.
These two factors are linearly related, and recording the change of electrical conductivity offers a possibility to track streamflow. This pilot study attempts to compare the velocity-area method as a benchmark with a tracer method: salt dilution in four mountainous streams in the Sumava Mountains, where problems with discharge measurement are often confronted.
This paper provides a theoretical background of these two methods and a detailed experimental setting for application. The results of the comparison show a great potential for the salt dilution method as an alternative to measure discharge when the conventional method is not suitable.
Overall, this study provides a basis for future work concerning establishment of a rating curve, constructing a constant injection station, and evaluating the uncertainties from both methods under different flow regimes.