Sediment Transport Modelling Workflows¶
Several typical work flows in modelling sediment transport are presented be-low.
Analysis of hydraulic effects of sediment deposits¶
This analysis focusses on the hydraulic effects (changes in flow capacity, overflows, surcharge, etc.) as consequence of fixed bed sediment deposits in a pipe network.
Step 1: Prepare a stable and well-calibrated drainage network model, loaded with representative hydraulic inflows
Step 2: Set the "Sediment transport | General parameters" analysis type to "Hydraulic effects only".
Step 3: From the ‘ST initial depths’ editor, specify initial sediment depths (fixed-bed sediment depths), globally and, optionally, locally. The local sediment depth specifications override global specification.
Step 4: From the ‘Pipes roughness’ editor, specify flow resistance for sediment deposits, globally and, optionally, locally. The local Manning number specifications override global specification.
Step 5: Review the contents of the default result file for sediment transport (Default_Network_ST) and include the wanted output items. Note that this type of analysis generates only result items "Bottom level", Bottom shear stress", and "Manning number". Alternatively, make a copy of default network result file, change its contents type to "Mixed contents" and add the wanted ST result items.
Step 6: Set up ST simulation. Create a simulation job, including "Hydrodynamic (HD)" and "Sediment transport (ST)" modules. Set appropriate simulation period, simulation time step and hot-start file (optionally).
Step 7: Review result files to be generated and set appropriate result saving frequency
Step 8: Run a simulation
Step 9: Review results
Analysis of wastewater sediments transport in a drainage network¶
This is a morphological analysis of sedimentation in a wastewater collection network. The analysis includes sediment loads from wastewater inflows generated on urban catchments, and their transport, sedimentation and erosion in the sewer network.
Step1: Prepare a stable and well-calibrated drainage network model, loaded with representative hydraulic inflows, defined as "Catchment discharge", representing wastewater generated by population in the catchments. Wastewater load is defined by quantity and diurnal variation.
Step 2: Set the "Sediment transport | General parameters" analysis type to “Basic morphological analysis". Choose the ST formula and review basic sediments properties (relative density and porosity of deposits).
Step 3: Specify at least one sediment fraction (Sediment transport | Sediment fractions) and review/modify its properties.
Step 4: Specify initial sediment depths), globally and, optionally, locally. The local sediment depth specifications override global specification.
Step 5: Specify flow resistance for sediment deposits, globally and, optionally, locally. The local Manning number specifications override global specification.
Step 6: Specify WQ Boundary properties for the wastewater boundary condition, as sediment concentration in wastewater, separately for each sediment fraction. The concentration may be given as a constant or as diurnal variation.
Step 7: Review the contents of the default result file for sediment transport (Default_Network_ST) and include the wanted output items. Alternatively, make a copy of default network result file, change its contents type to "Mixed contents" and add the wanted ST result items.
Step 8: Set up ST simulation. Create a simulation job, including "Catchment discharge”, “Hydrodynamic (HD)”, “Transport (AD,SWQ)” and “Sediment transport (ST)" modules.
Set appropriate simulation period, simulation time step for catchment dis-charge and for network simulation, and hot-start file for the network model (optionally).
Step 9: Review result files to be generated and set appropriate result saving frequency.
Step 10: Run a simulation
Step 11: Review results
Analysis of stormwater sediments buildup washoff first flush¶
Analysis of stormwater sediments buildup/washoff ("first flush") and sediment transport in a drainage network
This is a morphological analysis of sedimentation in a wastewater collection network. The analysis includes sediment loads from storm runoff, generated on urban catchments, and their transport, sedimentation and erosion in the sewer network
Step 1: Prepare a stable and well-calibrated drainage network model, loaded with representative rainfall, defined as "Rainfall" boundary condition.
Step 2: Set the "Sediment transport | Generel parameters" analysis type to "Basic morphological analysis". Choose the ST formula and review basic sediments properties (relative density and porosity of deposits).
Step 3: Specify at least one sediment fraction (Sediment transport | Sediment fractions) and review/modify its properties.
Step 4: Specify initial sediment depths), globally and, optionally, locally. The local sediment depth specifications override global specification.
Step 5: Specify flow resistance for sediment deposits, globally and, optionally, locally. The local Manning number specifications override global specification.
Step 6: Define buildup/washoff parameters for the specified sediment fractions or the model's catchments
Step 7: Define SWQ boundary condition (Stormwater loads (surface) and its WQ properties, based on SWQ advanced method "BuildUp Washoff".
Step 8: Review the contents of the default result file for sediment transport (Default_Network_ST) and include the wanted output items. Alternatively, make a copy of default network result file, change its contents type to "Mixed contents" and add the wanted ST result items.
Step 9: Set up ST simulation. Create a simulation job, including "Rainfall-Runoff (RR)”, Transport (AD, SWQ)", “Hydrodynamic (HD)” and “Sediment transport (ST)" modules.
Set appropriate simulation period, simulation time step for runoff and for net-work simulation, and hot-start file for the network model (optionally).
Step 10: Review result files to be generated and set appropriate result saving frequency
Step 11: Run a simulation
Step 12: Review results