Hydraulics of braided river dynamics. Insights from flume experiments

Abstract

We focus on the measurement of the topography and bathymetry in flume-models of braided rivers. To this aim, an innovative measurement system is adopted. It consists of a laser-ultrasonic sensor and can survey the bed elevation under flowing water. This measurement system was used to profile a flume transect with a frequency of 2 minutes, without stopping the water discharge. By this technique, the topography and the bathymetry of a single transect was continuously acquired in 3 braided rivers generated with the same experimental set-up. The main results are: (i) the quantification of the variability of the number of channels and number of active channels; (ii) the assessment of the probability distribution of some key hydraulic and morphodynamic parameters; and (iii) the verification of the repeatability of results obtained from flume-models of braided rivers.