Sediment Bed Core Initialization

Owned by Kester Scandrett
Last updated: 10 May, 2021 by Bui Bich Thuy (Deactivated)
4 min read

There are three options to initialize sediment bed in EE10 including Use Polygon DSM (polygon digital surface model), Use Sediment Cores with Grain-size and Create Uniform Bed. This page guides how to use sediment cores to set the sediment bed. After analysis in the laboratory sediment cores, data will be formatted in various ways. To import into EEMS, the sediment cores data needs to be formatted as shown in Figure 1.

Figure 1.  EFDC sediment core data file format.

To import the sediment core data file go to the Initial Conditions tab in Sediments and Sediment Bed Properties form.

Initial Conditions Tab

The sediment parameters form with the Initial Conditions tab selected is shown in Figure 2.

  • Select Spatially Varying Bed Conditions; Specify Mass Fraction and click on Assign Bed IC
  • In the new window, select Use Sediment Cores with Grainsize (Figure 3)
  • Browse to the sediment core file data e.g "Tra_Khuc_Sed_Cores.dat"
  • Define Max diameter of grains, Number of Initial Layers, Minimum Layer Thickness
  • Click Apply and a form summarizing the imported data is displayed as shown in Figure 4, click the "Exit" button
  • Click OK button in the form of Figure 3 and Figure 2 to finish.
  • Figure 5 shows the initial conditions of sediment bed in 2DH View

Figure 2.  Initial Conditions tab.


Figure 3.  Initialization of Sediments: Use Sediment Cores with Grain-size option.


Figure 4.  Summary reported of import of sediment cores.



Figure 5. 2DH View of sediment bed D50 with cores marked by symbols.

Sediment Core Data File Generation by EFDC_Explorer

The EE supports the creation of the sediment core data file from the 2DH View with the following steps:

  • In 2DH View, select Import an External Overlay Layer  under Layer Control (Figure 6)
  • The Open External Layer window will appear (Figure 7). Choose Sediment Bed Cores (*.dat) from the drop-down list then browse to the sediment core file data e.g "Tra_Khuc_Sed_Cores.dat"
  • A new Sediment Bed Core layer will appear, select this layer and ensure the edit function is on. RMC on any cell and select Create New Bed Core (Figure 8).

Figure 6.  Import an external layer.


Figure 7.  Select bed core data file to Import.


Figure 8.  Define new sediment core.


Sediment core data that has been analyzed and summarized may be used to manually update the core field. From the data set available, the user can extract the information then fulfill it in the form as shown in Figure 9. This requires the following steps:

  • Enter the name of the core ( e.g Core 73)
  • Select Add to add a new core layer
  • Enter UTM coordinates of the sediment core (X, Y in meters)
  • Enter Z value with a top elevation of bed core
  • The thickness of sediment layer, porosity, and specific sediment gravity (SSG)
  • Sieve size and percent passing of grain corresponding to each layer
  • Finally, click OK button to finish for Core 73. 

Figure 9.  Sediment Bed Core editing form.


After defining all the sediment cores the user should save out the cores by RMC on Sediment Bed Core and select Save Bed Cores as shown in Figure 10. A browse window will appear and the user should enter the name of the file and folder to store the file then click the Save button.

Figure 10.  Save Bed Cores option. 


Now the sediment core data file has been built and we can set the initial condition for sediment as shown in Figure 3.