The construction and operation of the hub will affect the formation of physical conditions in the process of water level,and lead to the inconsistency of the statistical samples of the design lowest navigable water level.However,rejecting the water level sequence before damage will lead to the lack of representativeness of the statistical samples.Taking Linhuaigang second ship lock as an example,we aim at the inconsistency of water level samples caused by the construction and operation of the junction and the impoundment in dry season,comprehensively consider the variation trend of upstream water,the influence of human factors on water level,the short-term and long-term operation plans and the actual situation of the project,determine the typical data of calculating the design lowest navigable water level,and obtain the design lowest navigable water levels above and below the gate.The results show that,the design lowest navigable water levels above and below the gate are 19.27 m and 17.14 m,which are calculated by the data from 2007 to 2018.