Flash floods result from a complex interaction among hydro-meteorological, hydrological, and hydraulic processes across various spatial and temporal scales. Sichuan Province suffers flash floods frequently owing to mo...Flash floods result from a complex interaction among hydro-meteorological, hydrological, and hydraulic processes across various spatial and temporal scales. Sichuan Province suffers flash floods frequently owing to mountain weather and topography. A flash flood and gravel bed load transport are two key relative problems in mountain river engineering. Bed materials are often encountered in alternate scouring and deposition in mountain fluvial processes during a flash flood. In this circumstance, CRS-1 bed load numerical model jointly with scale physical model is employed to predict water level and gravel bed scour and deposition for design of flood control dykes and flash flood disaster mitigation. A case study on the mechanism of a flash flood disaster induced by bed load transport for a hydropower station in Sichuan Province is conducted. Finally, suggestions to protect the hydropower station are proposed.展开更多
Suspended sediment transport in streams is an effective indicator of soil erosion at the watershed scale. This process was studied using the data obtained from two continuous monitoring stations installed in Italian w...Suspended sediment transport in streams is an effective indicator of soil erosion at the watershed scale. This process was studied using the data obtained from two continuous monitoring stations installed in Italian watersheds, the Rio Cordon and Torrente CarapeUe. The catchments have substantially different climatic, morphological and land use characteristics. The Rio Cordon, a small Alpine watershed, has been monitored since 1986, while in the Torrente Carapelle, a medium-size Mediterranean watershed, the monitoring station has provided data since 2007. Several flood events with suspended sediment transport were isolated in the two catchments, excluding those determined by snowmelt in the Rio Cordon as this process does not affect the Carapelle watershed. Analysis of the events showed different behavior in terms of hysteresis loop trends between water discharge （m3 S-1） and suspended sediment concentration （g 1-1） values, as the Rio Cordon confirms clockwise relationships most frequently, while counter-clockwise trends represent the majority of cases for the Carapelle Torrent. The different behavior of the two watersheds was further analyzed by evaluating relationships between the main hydrological parameters related to suspended sediment transport. Runoff controls the total sediment budget in both catchments. In contrast, it was noted that the runoff process does not interfere in the magnitude of the suspended sediment transport in the Rio Cordon catchment, while variations due to the larger size of the catchment area characterize the events in the Carapelle watershed. Lastly, a flow peak threshold that determines the advance or delay of the hydrograph peak with respect to the sedigraph peak was established for the Carapelle Torrent, while it was not reported in the Rio Cordon.展开更多
Coupled flood and sediment transport modelling in large-scale domains has for long been hindered by the high computational cost.Adaptive mesh refinement is one of the viable ways to solving this problem without degrad...Coupled flood and sediment transport modelling in large-scale domains has for long been hindered by the high computational cost.Adaptive mesh refinement is one of the viable ways to solving this problem without degrading the accuracy.This goal can be accomplished through mesh adaptation,e.g.,mesh coarsening and refining based on the dynamic regime of the flow and sediment transport along with bed evolution.However,previous studies in this regard have been limited to cases either without involving sediment transport or featuring flow-sediment-bed decoupling and the assumption of sediment transport capacity,which are not generally justified.Here,a coupled hydrodynamic and non-capacity sediment transport model is developed on adaptive non-uniform rectangular mesh.The proposed model is validated against experimental tests and numerical results based on the fixed meshes.It is demonstrated that the proposed model can properly capture shock waves,resolve the wetting/drying transition and reproduce morphological evolution.Compared with models based on the fixed meshes,the proposed model features great advantage in computational efficiency and holds promise for wide applications.展开更多
基金the key project of National Natural Science Foundation of China(No.50739002)
文摘Flash floods result from a complex interaction among hydro-meteorological, hydrological, and hydraulic processes across various spatial and temporal scales. Sichuan Province suffers flash floods frequently owing to mountain weather and topography. A flash flood and gravel bed load transport are two key relative problems in mountain river engineering. Bed materials are often encountered in alternate scouring and deposition in mountain fluvial processes during a flash flood. In this circumstance, CRS-1 bed load numerical model jointly with scale physical model is employed to predict water level and gravel bed scour and deposition for design of flood control dykes and flash flood disaster mitigation. A case study on the mechanism of a flash flood disaster induced by bed load transport for a hydropower station in Sichuan Province is conducted. Finally, suggestions to protect the hydropower station are proposed.
基金conducted within the framework of the Italian Research Project of Relevant Interest (PRIN2010-2011),prot.20104ALME4,“National network for monitoring,modeling,and sustainable management of erosion processes in agricultural land and hillymountainous area” National Coordinator Prof.Mario Lenzi (University of Padova)
文摘Suspended sediment transport in streams is an effective indicator of soil erosion at the watershed scale. This process was studied using the data obtained from two continuous monitoring stations installed in Italian watersheds, the Rio Cordon and Torrente CarapeUe. The catchments have substantially different climatic, morphological and land use characteristics. The Rio Cordon, a small Alpine watershed, has been monitored since 1986, while in the Torrente Carapelle, a medium-size Mediterranean watershed, the monitoring station has provided data since 2007. Several flood events with suspended sediment transport were isolated in the two catchments, excluding those determined by snowmelt in the Rio Cordon as this process does not affect the Carapelle watershed. Analysis of the events showed different behavior in terms of hysteresis loop trends between water discharge （m3 S-1） and suspended sediment concentration （g 1-1） values, as the Rio Cordon confirms clockwise relationships most frequently, while counter-clockwise trends represent the majority of cases for the Carapelle Torrent. The different behavior of the two watersheds was further analyzed by evaluating relationships between the main hydrological parameters related to suspended sediment transport. Runoff controls the total sediment budget in both catchments. In contrast, it was noted that the runoff process does not interfere in the magnitude of the suspended sediment transport in the Rio Cordon catchment, while variations due to the larger size of the catchment area characterize the events in the Carapelle watershed. Lastly, a flow peak threshold that determines the advance or delay of the hydrograph peak with respect to the sedigraph peak was established for the Carapelle Torrent, while it was not reported in the Rio Cordon.
基金supported by the National Natural Science Foundation of China(Grant Nos.11172217,51279144&11432015)
文摘Coupled flood and sediment transport modelling in large-scale domains has for long been hindered by the high computational cost.Adaptive mesh refinement is one of the viable ways to solving this problem without degrading the accuracy.This goal can be accomplished through mesh adaptation,e.g.,mesh coarsening and refining based on the dynamic regime of the flow and sediment transport along with bed evolution.However,previous studies in this regard have been limited to cases either without involving sediment transport or featuring flow-sediment-bed decoupling and the assumption of sediment transport capacity,which are not generally justified.Here,a coupled hydrodynamic and non-capacity sediment transport model is developed on adaptive non-uniform rectangular mesh.The proposed model is validated against experimental tests and numerical results based on the fixed meshes.It is demonstrated that the proposed model can properly capture shock waves,resolve the wetting/drying transition and reproduce morphological evolution.Compared with models based on the fixed meshes,the proposed model features great advantage in computational efficiency and holds promise for wide applications.
