3D Coastal Sediment Model - Tra_Khuc Estuary

1  Introduction

This tutorial document will guide you on how to set up a coastal sediment model based on the Tra_Khuc Estuary example that is available from the EEMS website. It is assumed in the following guidance that the hydrodynamic model of Tra_Khuc has been set so that the sediment transport can be added to this model. The hydrodynamic model need can be downloaded from this link Build a 3D Coastal Model .

2  Generate a Sediment Transport Model

Open the Tra Khuc Hydrodynamic Model (Figure 1).

Figure 1.  EE main form of Tra_Khuc Hydrodynamic Model.

2.1 Activate Sediment Modules

  1. In the Model Control form, RMC on Modules to open the EFDC Modules window. 
  2. In EFDC Modules, check the boxes (Original) Cohesive Sediments and (Original) Non-Cohesive Sediments  to activate sediment then click OK. The Sediments item will be added under Modules.

Figure 2.  Activate the sediment module.

2.2 Set Sediment Transport Parameters and Options

  1. Right Mouse Click on Sediments tab under Modules then click Settings to open Sediments and Sediment Bed Properties window (Figure 3).
  2. In the General tab the user inputs the number of Sediment Bed Layers, Cohesives, and Non-cohesives (Figure 4)

Figure 3.  Editing the sediment module.

Figure 4.  Sediment Transport – General tab.

Cohesives Tab

The user should input the values as shown in Figure 5 for the cohesive class. 

Figure 5.  Sediment Transport – Cohesives tab.

Non-Cohesives Suspended Tab

The user should input values for IC WC Conc, IC Bed Mass, Specific Gravity, and Median Diameter as shown in Figure 6. In the Equilibrium Conc, check on Van Rijin then click Set Parameters to initialize the sediment properties using the Van Rijn equations.

Figure 6.  Sediment Transport – Non-Cohesives Suspended tab.

Non-Cohesives Bedload

The Non-Cohesives Bedload tab is shown in Figure 7. Pressing the Initialize Constants button will bring up a dialog box asking the user to select the bedload approach to use (Figure 8). EFDC_Explorer sets the bedload transport constants to standard literature values for the computational approach selected.

Enter "1" then click OK button. Click Set All button to set all non-cohesive bedload to the current class (Figure 7).

Figure 7.  Sediment Transport – Non-Cohesives Bedload tab.

Figure 8  Bedload Constants Initialization form.

Morphology and Consolidation Tab

The Morphology & Consolidation  tab of the sediment properties option is shown in Figure 9. In this tab, the user may specify various bed consolidation and bed morphology settings.

Figure 9  Sediment Transport – Morphology and Consolidation tab.

Bed Processes

The Bed Processes is shown in Figure 10.

Figure 10.  Sediment Transport – Bed Processes tab.

Initial Conditions Tab

There are several ways to build sediment beds in EFDC_Explorer. The simplest option is to create a uniform bed as shown in Figure 11. Another option, using a sediment core with grain-size which is described in Sediment Bed Core Initialization.

The sediment parameters form with the Initial Conditions tab selected is shown in Figure 11.

  1. Select Spatially Varying Bed Conditions; Specify Mass Fraction
  2. Click Create Assign Bed IC button, Initialization of Sediment Beds window will appear (Figure 12). Click on Create Uniform Bed.
  3. Inorganic Sediment Bed Constructor window appears, enter values for uniform cohesives and non-cohesives as shown in Figure 13
  4. Then click Create Sediment Bed button
  5. Click on OK

Figure 11.  Sediment Transport – Initial Conditions tab.

Figure 12.  Initialization of Sediment Beds form.

Figure 13.  Uniform Sediment Bed Generation form.

2.3 Set Up Boundary Conditions for Sediment

1. From Model Control formunder External Forcing Data, RMC on Cohesives Sediment and select  Add New Data Series (See Figure 14) then the Boundary Data Series form appears.

2. In the Boundary Data Series form, click on Add New 

3. Input the name of the series as "River" in Series Name then press Enter key from the keyboard.

4. Enter time-series data of cohesive sediment from Figure 14 then click OK button to finish.

Figure 14.  Cohesive Sediment: add new data series.

Figure 15.  Cohesive sediment data series.

5. Add data time series for Non-Cohesives Sediment as shown in Figure 16 and Figure 17 (remember to put in data for 3 non-cohesive classes)

Figure 16.  Non-Cohesive Sediment: add new data series.

Figure 17. Non-cohesive sediment data series.

2.4 Assigning the sediment concentration BC

1. Return to the Model Control form, RMC on the River under Flow of the Boundary Conditions tab then select Edit Boundary Group (Figure 18)

Figure 18  Edit Boundary Group conditions.

2. The Flow Boundary Conditions form appears as shown in Figure 19, in Boundary Group Conditions, from the drop-down list, select data series with named as "River" for Cohesive Sediment and Non-cohesive Sediments , then OK button.

Figure 19.  Boundary Condition Definition/Groups form.

3  Save and Run Sediment Model

  1. Click the Save Project button  on the top of EE form to save the model again as shown in Figure 20.
  2. Click the Run EFDC  button, the EFDC+ Run Options frame appears as shown in Figure 21. On this form, the user can set the number of threads, output interval then browse to the EFDC+ executable file. Then click Run EFDC+ button to run the model.
  3. The EFDC+ run window is shown in Figure 22.

Figure 20.  Save and run model.

Figure 21.  EFDC+ Run Options.

Figure 22.  EFDC+ run window.