ABSTRACT
Throughout this chapter, we emphasized the diversity of processes that contribute to flood generation. These mechanisms do not act in an isolated manner; they form a continuous process domain. It follows that in a single watershed, several associated processes can take place during the same rainfall event. Similarly, it can happen that the type of processes changes depending on the type of rainfall event. The floods generated in summer and winter do not necessarily involve the same types of processes. It is also difficult to characterize, together, all the processes involved in flood generation. Dune (1978) proposed a classification of the dominant processes based on three criteria: peak lag time, peak runoff rate and the surface area of the watershed. Figures 11.16 and 11.17 illustrate these classifications. They show the distinctions between Horton overland flow, saturation overland flow, subsurface flow or throughflow and the two types of pipeflow.
