This tool calculates the sedimentation of an access channel over a certain period of time. The location and length of the access channel needs to be defined under 'Generic data' (as a structure with type: Access channel). Using the geometrical input of the access channel the initial profile over the full length is calculated. Based on the theory of Van Rijn (Basics of channel deposition/siltation, 2013) and the input parameters the sediment transport due to tidal flow and waves outside of the channel is calculated.
Subsequently, the trapping of bed load and suspended load is defined including resulting sedimentation within the channel. At the end of each calculation round the channel dimensions over the full length are updated and used as input for the following calculation round.
Please be aware that the speed of the calculation scales:
A number of user input fields are provided which can be used to adjust the calculation according to the local situation. Default values are provided for each input field.
The following inputs are defined:
 Default Value  Unit  Min.  Max.  Brief Description 
Channel bed level  10  m+MSL  0  1000  The initial bed level of the dredged channel. Check on deeper than local bed level 
Channel width  200  m  0  1000  Width of the bottom of the dredged channel at the start of the calculation 
Side slopes  3  m/m  0  100  The side slope of the channel indicated by 1 meter up, X meter to the side [1:X] 
 Default Value  Unit  Min.  Max.  Brief Description 
Tidal Direction  30  °N  360  360  Tidal flow direction during flood. Direction is measured compared to North (positive in clockwise direction) 
Phase difference tidal levelflow  90  °  360  360  Phase difference in tidal level versus tidal flow. In case of 0° flow velocity is peaking together with the maximum water level. 
 Default Value  Unit  Min.  Max.  Brief Description 
Suspended concentration Clay  0.1  kg/m3 

 Clay concentration at upstream boundary (outside channel). 
Suspended concentration Silt  0.005  kg/m3 

 Silt concentration at upstream boundary (outside channel). 
Settling velocity Sand  0.02  m/s  0.005  0.05  Settling velocity suspended sand (>50 microns). 
Settling velocity Silt  0.001  m/s  0.0005  0.005  Settling velocity suspended silt (10 to 50 microns). 
Settling velocity Clay  0.0001  m/s  0.0001  0.0005  Settling velocity suspended clay (< 10 microns). 
 Default Value  Unit  Min.  Max.  Brief Description 
Method trapping efficiency  1 
 1  2  1 – Method of Van Rijn 2 – Method of EysinkVermaas 
Coefficient Van Rijn  0.26 
 0.1  0.4  Coefficient Van Rijn 
Bulk method  0 
 0  1  0 – Consolidation factor 1 – Constant value 
Bulk density Sand  1.55  ton/m3 

 Sedimented Sand will occupy a volume according to this factor. 
Bulk density Silt  1.12  ton/m3 

 Sedimented Silt will occupy a volume according to this factor. 
Bulk density Clay  0.415  ton/m3 

 Sedimented Clay will occupy a volume according to this factor. 
 Default Value  Unit  Min.  Max.  Brief Description 
Total time period  12  month(s) 

 Simulation period in months. 
Calculation rounds incl. bed update  2  rounds  1  10  Number of calculation rounds equally divided over total time period. Each calculation round starts with updated bathymetry. 
Number of calculation points  10  points  2  100  Number of calculation points. The start and end of the channel and other vertices are always included. 
 Default Value  Unit  Min.  Max.  Brief Description 
Sensitivity parameter: Channel width  0  %  0  50  Possible change or uncertainty in Channel width 
Sensitivity parameter: Settling velocity  0  %  0  50  Possible change or uncertainty in Settling velocity 
Sensitivity parameter: Tidal flow  0  %  0  50  Possible change or uncertainty in Tidal flow 
Sensitivity parameter: Tidal direction  0  °  0  15  Possible change or uncertainty in Tidal direction 
Linear wave theory is applied to translate offshore wave conditions into local nearshore conditions along the channel.
Influence of the channel on the propagation and dissipation of waves is not included in this analysis. Also the influence of bathymetric variety and structures on hydrodynamic flow and sediment transport are not included in this analysis. This will require more advanced numerical modelling.
The following files (.dsproj) can be downloaded and loaded into CoDeS to serve as examples. They are not based on actual projects, but are intended as illustration.
Unzip the files to an convient folder (but make sure the file structure does not change), and open the .dsproj file from within CoDeS.