Flooding processes
Flood risk prevention

To understand this process, we need to analyze the various factors that contribute to the formation and temporary increase in river flows. To simplify, we distinguish between :

• mobilizable water, made up of water received by the watershed ;

• runoff, corresponding to the proportion of water that has not infiltrated the soil. It depends on the nature of the soil, its surface occupation and the intensity of the rainfall event;

• time of concentration, defined as the time required for a drop of water to reach the watershed outlet from the point furthest away;

• flood wave propagation, a function of the structure of the bed and alluvial valley, in particular the slope and characteristics of the floodplain.