Sediment Bed Core Initialization

Owned by Kester Scandrett
Last updated: 20 Jul, 2018 by Duy Pham

There are three options to initialize sediment bed in EFDC_explorer including Use Polygon DSM (polygon digital surface model), Use Sediment Cores with Grainsize and Create Uniform Bed. This page guides how to use with sediment cores. Sediment cores samples are analyzes in laboratory and recorded in reports. sediment cores data will be summarized and formatted from the reports as shown in Figure 1.

Figure 1  Sediment Core Data File Format.

Since the sediment core data file is available, the user goes to the Initial Conditions tab in Sediments and Sediment Bed Properties form.

Initial Conditions Tab

Figure 2 shows the sediment parameters form with the Initial Conditions tab selected.

  • Select Spatially Varying Bed Conditions; Specify Mass Fraction
  • Select Use Sediment Cores with Grainsize
  • Browse to the sediment core file data e.g "Trakhuc_Sed_Cores.dat"
  • Define Max diameter of grains, Number of Initial Layers, Minimum Layer Thickness
  • Then click Apply then a window form displayed as shown in Figure 3, click OK button
  • Click OK button in the form of Figure 2 to finish.
  • Figure 4 shows the initial conditions of sediment bed in ViewPlan.

Figure 2  Initial Conditions-Use Sediment Cores with Grainsize Option.

Figure 3  Reported Sediment Cores Window.


Figure 4  ViewPlan Sediment Bed d50 with Cores Symbols.

Sediment Core Data File Generation by EFDC_Explorer

The EE supports users to create the sediment core data file as following steps:

  • Go to ViewPlan then select Sediment Bed in Viewing Opt's
  • From the keyboard press Ctrl+T to Toggle Sediment Core Editing (Press F2 to see)
  • RMC on the grid domain then select Define New Core (See Figure 5)

Figure 5  Define New Sediment Core.


Sediment cores are analyzed from the lab and recorded in the report. From the report the user can extract the information then fulfill in the form as shown in Figure 6, it includes the following information 

  • Put a name of core ( e.g Core70)
  • Enter UTM coordinates of the sediment core (X, Y in meter)
  • Enter Z value with top elevation of bed core
  • Thickness of sediment layer, porosity and specific sediment gravity (SSG)
  • Sieve size and percent passing of grain corresponding to each layer
  • when it is done for each layer, the user click Add button to add the sediment layer.
  • the user can update data for a layer by select the layer then change data its properties or delete the select layer
  • Finally click OK button to finish for Core70. And the user can repeat by steps in Figure 5 and Figure 6 for next sediment core.

Figure 6  Sediment Core Editing Form.

After defining sediment cores finished, the user should save out the cores by Right-Mouse Click then select Save Cores as shown in Figure 7. A form as shown in Figure 8 appear, the user put a name of the file and folder to store the file then click Save button.

Figure 7  Save Cores Out (1).

Figure 8  Save Cores Out (2).

So now we have the sediment core data file and we can set initial condition for sediment as shown in Figure 2.