ABSTRACT
The relatively low safety level of the sea dikes in Vietnam was noticed in 1996 during two visits of Dutch expertise missions (DWW/RWS 1996a, b). Most designs of the sea dikes in Vietnam are based on loads with return period 20 year or even shorter periods. Compared to the Dutch standard (return periods 1000 to 10000 year) these return periods are very small. Besides this fact the Dutch mission marked that most Vietnamese dikes were designs as poor and disputable (DWW/RWS 1996a, b). As a result the true probability of failure of the Vietnamese water defense system exceeds by far the design frequency (Mai Van et al. 2006, 2007). Although designed to fail once in 20 to 25 year the sea defense system might well fail almost every year. The experiences in the past 20 years support this statement.
