Discussion On Guaranteed Rate Of Construction Water Level Of Port Engineering In Fluctuating Backwater Area Of Reservoir Based On Stochastic Process

In the mountain river, the construction of water conservancy project makes theriver’s natural state and hydrological characteristics be changed, and the relationshipbetween the flow and water level has been significantly different, especially in thefluctuating backwater area. It affects the design and construction of port engineering inthe river. Therefore, it is meaningful to select the construction water level of portengineering in the fluctuating backwater area in a scientific and rational manner for theactual project. Based on the flow data of port engineering of upstream hydrologicalstation, this paper analyzes and selects the construction water level by applying flow timeseries, flow model, empirical method and simulation method. The main researchcontents include:（1）According to the flow data of project reach, this paper established the flowtime series model. And through the model, it can get much data by fitting andforecasting which provides a basis for the following calculations.（2）This paper established flow model by applying HEC-RAS, through thecomparison and selection of the model parameters, it could calculate the water leveltime series in two different flow conditions in natural conditions and typical scheduling.It provided sufficient data for the calculation of the pier design low water level and theapplication of probabilistic methods to discuss the selection of construction waterlevel.（3）By summarized existing methods of determining construction water level, itcalculated pier design low water level by synthetic duration curve method andduration-frequency method, construction level in its design low water level above1.5to2.0m around. It analyzed the relationship between the value of construction waterlevel and guaranteed rate. It compared the range of construction water level underdifferent methods and gave an optimum value. The article discusses the value of theconstruction level, only the water level reference factors, temporarily not take intoaccount the economic evaluation.On the basis of the comprehensive utilization of time series model and the flowmodel, through empirical method and simulation method，the paper provides the morescientific and rational selection of the guaranteed rate of construction water level of engineering construction in the backwater area which is meaning to the engineeringconstruction.