The Research For Navigation Risk Evolution In Fluctuating Backwater Zone Of The Three Gorges Reservoir

The Yangtze River is the longest and most developed inland water transport system in China,supporting the implementation of the national strategy of “high-quality development of the Yangtze River Economic Belt” and playing an important role in promoting the development of the Yangtze River Economic Belt and the integration of the “Belt and Road”,which has an important strategic position in China.The Three Gorges Dam is one of the most important dams on the Yangtze River.The Three Gorges Dam is an important water conservancy project on the Yangtze River,which serves the functions of power generation,flood control and shipping.Since the completion of the Three Gorges Dam,the upstream waterway conditions have improved,which is conducive to ship navigation.The scheduling operation of the Three Gorges Dam causes the water level in the reservoir area to change periodically between 145 m and 175 m,thus forming a backwater change zone.When the reservoir level is 145 m,the water surface line of the reservoir ends at the end of the reservoir’s perennial backwater zone,which is located at Guanyintan,Changshou(583.0km upstream of the Yangtze River),and the backwater change zone shows the characteristics of a natural river channel;When the water level in the reservoir zone is 175 m,the end of the water surface line in the reservoir zone is the end of the whole reservoir,located in Jiangjin Hong Hua moraine(720.0km upstream of the Yangtze River channel mileage),at this time the change back to the waterway in the zone shows the characteristics of an artificial reservoir.When the reservoir level is between 145m(lowest water level)and 175m(highest water level),the river section from the end of the Three Gorges reservoir area to the end of the perennial backwater zone in the Three Gorges reservoir area shows the dual characteristics of a natural river channel and an artificial reservoir.The changing hydrological and navigational conditions in the backwater change zone make the navigational conditions in the backwater change zone of the Three Gorges Reservoir more complex.With the change of the operation stage of Three Gorges Dam,the navigation channels under different water levels show different characteristics,which have a great impact on the navigation safety of ships and bring great challenges to maritime supervision.Therefore,it is of practical significance to carry out research on the evolution of the risk of ship navigation in the backwater change zone of the Three Gorges reservoir,analyze the interaction between the factors influencing the risk of ship navigation in the backwater change zone of the Three Gorges reservoir,explore the evolution of the risk of ship navigation in the backwater change zone of the Three Gorges reservoir,and provide control measures and suggestions to reduce the risk of ship navigation in the Three Gorges reservoir.The main work done in this paper is as follows.(1)Taking the risk of ship navigation in the changing backwater area of the Three Gorges reservoir area as the research object,the current situation of ship navigation safety in the changing backwater area of the Three Gorges reservoir area is summarized and its risk factors are analyzed by reviewing relevant literature such as theses,the Yangtze River Yearbook and the annual report of the Maritime Bureau.(2)Screening the measurement variables of the navigational risk of ships in the Three Gorges reservoir area based on the analysis of the influencing factors of the navigational risk of ships in the changing backwater of the Three Gorges reservoir area,initially classifying the influencing factors of the navigational risk of ships in the changing backwater of the Three Gorges reservoir area into medium natural environment,channel environment,ship factor,crew factor and management factor,and designing the study of the evolution of the navigational risk of ships in the changing backwater of the Three Gorges reservoir area on this basis questionnaire to determine the latent variables of ship navigation risk in the changing backwater area of the Three Gorges reservoir area.(3)A ship navigation risk evolution model was established based on information flow theory to determine the structural model of ship navigation risk evolution in the changing backwater area of Three Gorges reservoir area.The questionnaire data were analyzed by AMOS software,and the model of ship navigation risk evolution in the changing backwater area of Three Gorges Reservoir was tested and optimized.(4)According to the "optimized risk evolution model of ship navigation safety in the changing backwater area of Three Gorges reservoir area",the information flow theory was applied to analyze the risk evolution law of ship navigation in the changing backwater area of Three Gorges reservoir area,and the process of risk evolution was divided into macro,meso and micro,and the process of risk evolution into accident was divided into inherent risk,risk emergence,risk release and accident formation in the micro.risk emergence,risk release and accident formation.(5)Finally,the current situation of ship navigation safety in the changing backwater area of the Three Gorges reservoir area is considered,and the corresponding risk control countermeasures and safety management suggestions are proposed from the perspective of information flow,taking into account the risk evolution law of ship navigation in the changing backwater area of the Three Gorges reservoir area.