Rational regime relationships for the width, depth and slope of a channel in equilibrium are developed using the Ackers and White sediment transport formulae and the White, Paris and Bettess friction relationships, together with the principle of maximum sediment transporting capacity. Favorable comparisons are made with data from sand and gravel channels and with existing empirical regime relationships.

Slit-check dams are widely employed in mountain river control. However an analysis of their performance in the field is still lacking. In the present work a field verification to evaluate the interaction between solid discharge regime and four slit-check dams built in two subcatchments of the Versilia River in Tuscany, Italy is presented. The analysis is based on a relatively detailed field knowledge consisting of hydrological, topographical, and sedimentological data, together with a recent model proposed by Armanini and Larcher. Slit-check dam efficiency is analyzed in terms of deposit formation during major floods and its influence on long-term sediment transport regime. Results suggest that the design efficiency is affected by the high sediment trapping capacity associated with the relatively minor floods. A comparison between the deposit geometry predicted by the theory and the field measurements gathered during a systematic monitoring activity shows good agreement.

Side weir flows induce complex three-dimensional (3D) structures on the flow field in the main channel. Extensive experiments at the laboratory scale were conducted in order to investigate the flow field for the particular case of a side weir with a zero height crest in both fixed bed and steady flow conditions. Detailed measurements of the flow surface, discharge, and velocity field were performed in the main channel upstream, alongside, and downstream of the side weir location. They allowed detection and analysis of the three-dimensional flow structures. Elaborations of the measurements show the implications of such three-dimensional nature of the flow on integral quantities such as Coriolis and Boussinesq coefficients as well as the specific energy and discharge coefficient that are important in the widely used one-dimensional (1D) models. Moreover, the results may help to better understand other free-surface problems similar to the side weir flow, such as lateral diversions, river bifurcations, and levee breaches.