Hydrodynamical, morphodynamical and ecological river processes and their multiple linkages occur in an infinity of different configurations and over a wide range of spatial and temporal scales. This paper illustrates a research methodology that consists in combining field investigations, physical modeling in the laboratory, and numerical simulations in order to develop generic insight and tools for engineering and management of the river environment. This combined methodology is illustrated in research on (i) the macroscale characteristics of the velocity distribution and their relation to long-term and large-scale planimetric river processes, (ii) the flow field in the vicinity of the river bank and its importance with respect to bank erosion and, (iii) linkages between the characteristics of the mean flow and the turbulence on the one hand, and the behavior of invertebrates on the other. The reported research strongly relies on the use of state-of-the-art measuring instruments as well as numerical techniques.