Starting from establishment of the expressions of navigation suspension duration of Synthetic Duration Curve method and Low Tide Cumulation Frequency method, a new standard system of waterway design lowest navigable stage is suggested, the most obvious characteristics of which is that it accords the resulted design water stage of the two calculation methods mentioned above.

From building the expressions of suspending duration about Duration-Frequency method and Synthetic Duration Curve method,this paper suggests to establish a new standard of waterway design lowest navigable stage,according to which,the design stages calculated by the two methods are basically in accord with each other,so they have the same reliability.

In determining the design lowest navigable stage of the same-class waterway according to "Standards for Inland Navigation" and "Codes for Inland Waterway and Port Hydrology", the durations when water stage is lower than the design lowest navigable stage calculated by duration-frequency method, synthetic duration curve method and low tide cumulative frequency method were not equivalent basically.

According to the variation law of the lowest navigation stage in the upstream channel of Xijin hydropower junction and the objective condition of upstream reservoir inflow adjustment,this paper puts forward suggestions on the calculation method and parameters of design lowest navigable stage in the upstream channel of Xijiang reservoir area.

Based on the in-depth analysis of the computation result of the design lowest navigable stage for the basic stations of Gong River in Guangdong Province, i.

Computation of designed lowest navigable stage in lower reaches of Ganjiang River;

Study on method of calculating designed lowest navigable stage at downstream stretch of hydro-junction;