The degree of protection at any arbitrary cross-section of the levee is defined as the minimum flood exposure, which the levee is just capable of withstanding without special protective measures. The degree of protection offered by a levee section can be found by statistical analysis. For finding the minimum flood exposure the potential causes of failure must be investigated. These are influenced by the shape of the flood hydrograph i.e., by hydrological conditions, the seepage, i.e., hydraulic phenomena within the levee body, geological and soil mechanical factors depending on the quality of soils in the levee and its subsoil, and finally by wave action, which is controlled by topography and the meteorological conditions. Mathematical models of identical character lend themselves for the analysis of each of the four phenomena. The mathematical model serving the determination of the flood exposure critical for wave action is presented as an example. The probability of the highest flood stage increased by wave height can be computed therewith for the cross-section under consideration.