Measurement of the travel time in the upper Yellow River in 2015

The solute travel time in steady and gradually varied flow in rivers is necessary for waste transport studies, in particular, to evaluate the behavior of accidentally spilled soluble substances in streams. This study conducted two dye tests on the Donghe reach within Baotou in the upper Yellow River to measure the travel times in October 2015. It reconstructed the leading and trailing edge missed data by extension from time-concentration curves developed by fitting a three-parameter log-normal (3PLN) equation to the discretely observed data. It also calculated the travel times, dispersion rates, and longitudinal dispersion coefficients. The results show that the calculated travel rates of the centroid are less than the velocities at the Baotou hydrometric station. The calculated longitudinal dispersion rates ranged from about 0.22 meters per second to 0.68 meters per second. Using the nonlinear best fit method, a dispersion model for an instantaneous injection of tracer gave the longitudinal dispersion coefficients ranging from about 76 square meters per second to about 304 square meters per second. However, the ones generated by some commonly used empirical equations are at least 2.6 times them. Tracing tests are essential to obtain helpful information for pollutant transport studies.