In the light of the historical substantial data (covering a 70-year period) collected in the Lower Jingjiang segment and aided by topological grey method, here we attempt to characterize the occurrence and future tren...In the light of the historical substantial data (covering a 70-year period) collected in the Lower Jingjiang segment and aided by topological grey method, here we attempt to characterize the occurrence and future trend of flood calamities in the study area. Our findings indicate that overall the high-frequent flood disasters with middle to lower damage prevail at present. A series of dramatic flood waves will appear in the years of 2016, 2022, 2030 and 2042, particularly a destructive flood will occur between 2041 and 2045 in the Lower Jingjiang reaches. Typical of sensitive response to flood hazards in close association with its special geographical location, the lower Jingjiang segment hereby can reflect the development trend of floods in the middle Yangtze reaches. According to the results, a good fitness was revealed between the prediction and practical values. This actually hints that the topological grey method is an effective mathematical means of resolving problems containing uncertainty and indetermination, thus providing valuable information for the flood prediction in the middle Yangtze catchment.展开更多
The Jingjiang Reach is experiencing continuous channel degradation owing to operation of the Three Gorges Project(TGP)in2003.Significant retreat processes at composite riverbanks have occurred at local sites of this r...The Jingjiang Reach is experiencing continuous channel degradation owing to operation of the Three Gorges Project(TGP)in2003.Significant retreat processes at composite riverbanks have occurred at local sites of this reach,which may influence the stability of the river regime and the effect of existing river training works.Therefore,bank retreat plays a key role in fluvial processes of the Jingjiang Reach,and it is necessary to predict the long-term processes of bank retreat at typical sections in the reach.In this study,various factors influencing bank retreat in the Jingjiang Reach are investigated,based on bank erosion processes at four sections and the corresponding flow and sediment conditions.It is discovered that fluvial erosion intensity is a dominant factor in controlling the processes of bank retreat in the reach,although other factors,such as bank soil properties,can also influence bank retreat.The bankfull width at a section with severe bank erosion since 2002 is defined as being equal to the sum of the bankfull width in 2002 and the accumulated bank retreat distance after 2002.The magnitude of the bankfull width can be expressed as an exponential function of the previous 5-year average fluvial erosion intensity during flood seasons.The accumulated distances of bank retreat at four sections over the period 2002–2012 are predicted using the proposed empirical relationships,with the calculated bank retreat processes agreeing well with observed data.展开更多
文摘In the light of the historical substantial data (covering a 70-year period) collected in the Lower Jingjiang segment and aided by topological grey method, here we attempt to characterize the occurrence and future trend of flood calamities in the study area. Our findings indicate that overall the high-frequent flood disasters with middle to lower damage prevail at present. A series of dramatic flood waves will appear in the years of 2016, 2022, 2030 and 2042, particularly a destructive flood will occur between 2041 and 2045 in the Lower Jingjiang reaches. Typical of sensitive response to flood hazards in close association with its special geographical location, the lower Jingjiang segment hereby can reflect the development trend of floods in the middle Yangtze reaches. According to the results, a good fitness was revealed between the prediction and practical values. This actually hints that the topological grey method is an effective mathematical means of resolving problems containing uncertainty and indetermination, thus providing valuable information for the flood prediction in the middle Yangtze catchment.
基金supported by the CRSRI Open Research Program(Grant No.CKWV2014204/KY)the National Natural Science Foundation of China(Grant Nos.51079103 and 51339001)the National Basic Research Program of China("973" Project)(Grant No.2012CB417001)
文摘The Jingjiang Reach is experiencing continuous channel degradation owing to operation of the Three Gorges Project(TGP)in2003.Significant retreat processes at composite riverbanks have occurred at local sites of this reach,which may influence the stability of the river regime and the effect of existing river training works.Therefore,bank retreat plays a key role in fluvial processes of the Jingjiang Reach,and it is necessary to predict the long-term processes of bank retreat at typical sections in the reach.In this study,various factors influencing bank retreat in the Jingjiang Reach are investigated,based on bank erosion processes at four sections and the corresponding flow and sediment conditions.It is discovered that fluvial erosion intensity is a dominant factor in controlling the processes of bank retreat in the reach,although other factors,such as bank soil properties,can also influence bank retreat.The bankfull width at a section with severe bank erosion since 2002 is defined as being equal to the sum of the bankfull width in 2002 and the accumulated bank retreat distance after 2002.The magnitude of the bankfull width can be expressed as an exponential function of the previous 5-year average fluvial erosion intensity during flood seasons.The accumulated distances of bank retreat at four sections over the period 2002–2012 are predicted using the proposed empirical relationships,with the calculated bank retreat processes agreeing well with observed data.
