Reviewing

General comments: This paper deals with the evolution of river models, including meandering river and braided river, as well as their connection to the dynamics of estuaries. The study is based on laboratory experiments performed by some of the authors and available in the literature. They are composed of two sets of experiments in two different apparatus: one focusing on the influence of fine particles on the generation of either braided river or meandering river, and the other one modelling the dynamics of the estuary. The aim of the present paper is to provide a numerical modelling of the fluid flow for these different experimental observations, in place of experimental measurements, which are hardly accessible for such complex systems. In particular, a shallow model solver, Nays2D, is used for that purpose.