It refers to space during dam crest level; it is above maximum deposited beach face, storage bottom and normal water level as well as under maximumfloodlevel.
某坝顶标高时，最高沉积滩面、库底、正常水位三者以上，最高洪水位以下的空间。
2
As an example, the overtop failure probability of a dike under different floodwater standards is analysed using measured annual maximumfloodlevel at a hydrological station.