Application of Reliability Theory to Hydraulic Engineering Design

The reliability of two hydraulic engineering systems with random resistance and/or loading is estimated. The first system is a flood levee reach that is subject to four failure modes: overtopping, boiling, slope sliding and wind wave erosion. The second system is a flood levee system along a confluence reach. For this levee, failure by overtopping depends on the bivariate distribution of water stages in the tributary and the main river, linked by a backwater curve. The failure probability, which is the complement of reliability, is estimated analytically for the first system, and then by hydraulic calculations and simulation for the second system. In each case, estimated reliabilities agree well with experimental observations.