The bathymetry of Lake Washington shows that it is a deep, narrow, glacial trough with steeply sloping sides and approximately 65 m deep at its deepest point . These morphologic features are highly suitable for application of the SGZ model.
This tutorial document will guide you how to setup Sigma Zed model by using the EFDC_Explorer (EE). It will cover preparation of the necessary input files for the EFDC model and visualization of the output by using the EFDC_Explorer (EE) Software.
The data used for this tutorial are from Lake Washington. All files for this tutorial are found in Lake Washington model downloadable from the EE website.
Before going to each session, let’s us first introduce about the main form of EE User Interface in order to better understand our explanation hereafter. Figure 1 is the main form of EFDC_Explorer or EE User Interface. Functioning for individual icons are described as following;
Figure 1 EFDC Explorer Main Form.
This session will guide you to import the grid into EFDC_Explorer. With a complicated grid such as this the grid generation software CVLGrid has been used. Lake Washington in Washington state, the USA will be chosen as an example of building a 3D Lake Model with Sigma Zed in EE.
The gird generation process includes following steps:
Figure 2 Generate EFDC Model form.
Figure 3 Import grid options.
4. Click Generate button and finish. A dialog will pop up to show the gird information (see Figure 4).
Figure 4 Newly created grid information.
5. Save the model by select this button and create a new directory as shown in Figure 5.
Figure 5 New model saved.
This section will guide you how to assign the initial conditions such as the bathymetry, water level and bottom roughness.
Figure 6 Assigning the Initial Conditions.
Figure 7 Assigning model bathymetry.
The next step is to assign the initial depth or water surface elevations. There are two options for setting the surface water elevation that are Use Constant and Use Point Measurements/Gridded Data. In this case we will use the former option.
Figure 8 Assigning water surface elevation.
Figure 9 Assigning bottom roughness.
This next step is to prepare for the boundary conditions and assign these to the model grid. In this model there are seven flow boundaries, all but one of which are rivers flowing into Lake Washington. The Lock BC is an outflow. Figure 10 shows flow boundaries of the model.
Figure 10 Inflow and outflow of Lake Washington.
Figure 11 Assigning Flow Boundary Conditions.
Figure 12 Editing the Boundary Time Series.
6. Click to the Current button to view the current time series. If there are a number of layers then check Sum Layers to show total flow. (See Figure 13).
Figure 13 Flow Time Series Plot.
7. Change up/downward this button to edit other time series.
8. Click OK to finish editing the boundary time series.
Figure 14 Assigning Temperature Boundary Conditions.
Figure 15 Editing the Boundary Time Series.
6. Click to the Current button to view the current time series. (See Figure 16).
Figure 16 Editing the Boundary Time Series.
Figure 17 Assigning Winds Boundary Conditions.
Figure 18 Editing the Boundary Time Series.
Figure 19 Editing Wind Station Parameters.
Figure 20 Wind Rose.
Figure 21 Assigning Atmospheric Boundary.
Figure 22 Editing the Boundary Time Series.
Figure 23 Editing ATM Station Parameters.
Figure 24 Viewing ATM Data.
When all required boundary time series are prepared. You have to assign those boundary time series into the model cells.
In order to assign the flow boundary, the following steps should be taken
1. Click to the 2D Planview icon on the main form (See Figure 1 ).
2. Choose Boundary C’s in the Viewing Opt’s .
3. Check Enable Edit and Show Grid (See Figure 25).
4. In order to know locations of cells assigned flow BC, the user should load the labels file (BC Location.dat). Go to "Display Options" in the top menu of 2D ViewPlan then go to "Annotations", next load the label file as shown in Figure 26 and Figure 27.
Figure 25 Assigning Boundary Condition Cells.
Figure 26 Loading Label File.
Figure 27 Labels Displayed
5. Zoom in to each label location then Right-Mouse-Click on the inflow/outflow location cell/ choose New (See Figure 28).
6. Enter the boundary group ID: Inflow group (See Figure 29 ).
7. Select boundary types. It is dependent on your current boundary type to choose the suitable boundary type. In this case, we have 1 flow boundary so we choose number 1 (See Figure 30).
8. Select the associated with this inflow boundary time series. (See Figure 31). then click OK to complete.
Figure 28 Right-Mouse-Click on the inflow cell.
Figure 29 Enter Boundary Group ID.
Figure 30 Select the Boundary Types.
Figure 31 Assign the Corresponding Time Series.
9. The boundary cells might have multiple cells to present the real river width. In order to assign the next cell as inflow cell, you need to come back to step 5 and Right-mouse Click to that cell and choose Add to Adjacent. The inflow is now divided to the number of assigned cells. (See Figure 32).
Figure 32 Assign the more boundary cells.
Temperature boundary associated with flow boundary, in this case there two temperature boundary, one is associated with Cedar River inflow and the other is related to Sammamish River inflow. The following steps should be taken:
Figure 33 Right-Mouse-Click on the inflow cell.
Figure 34 Assign Temperature Boundary.
Figure 35 Assign Temperature Boundary.
Figure 36 SGZ Layering Options Form.
Figure 37 SGZ Layering Options Information.
When the user click Activate Modules tab, a list of modules will be displayed for selecting. Check on box of Activate Temperature as shown in Figure 38. After that the Temperature tab will be turned on (See Figure 38). Click Temperature tab, a form will appear as shown in Figure 39
Click Assign button to assign initial condition for temperature. In the appeared form, the user set values as shown in Figure 40 then click Apply and Done button to finish.
Figure 38 Activate Modules.
Figure 39 Temperature Module Form.
Figure 40 Assigning Initial Temperature Form.
Figure 41 Surface Heat Exchange Settings.
Figure 42 Bed Heat & Ice Options Settings.
After above sessions, you are almost having a hydrodynamic model. This part will guide you how to setup the model simulation time and model time steps.
Figure 43 Model Run Time.
Table 2 Model Run Time Explanation.
Name | Explanation |
Time of Start (days) | Julian starting date (an automate conversion to Gregorian date is there) |
# Reference Periods | Total simulation time (an automate conversion to Gregorian date is there) |
Duration of Reference Period (hours) | Reference period |
Time Step (second) | Delta T |
Safety Factor | 0<Safety Factor < 1 to active the Dynamic time step |
# Ramp-Up Loops | Number of initial interaction to hold the time step to a constant during ramp-up |
Maximum dH/dT | If >0 then it is an additional criteria to determine the dynamic time step. |
Beginning Date/Time | The base date of all data and simulation period. |
3. Select the EFDC_Explorer Linkage to set the EFDC Results to EFDC_Explorer Frequency. 60 minutes mean that the EE will store the output in every 60 minute for displaying the model results in the EE. (See Figure 44). Note that, smaller output frequency will cause larger output file.
Figure 44 Setting Linkage Output Frequency.
This session will guide you how to set the hydrodynamic model. Since the EFDC model is applied the Wet and Dry condition to optimize the simulation time. Thus, we should set for this condition as following:
Figure 45 Hydrodynamic Model Setup.
Figure 46 HMD Modify Form.
Figure 47 Browse to the EFDC Executable File.
2. Step 2: Select the Run EFDC icon to on the main form and click the Run EFDC_DSI button to run the model (Figure 48).
Figure 48 Run EFDC Setting.
If everything are setting well, the model will start running and you will see the MS-DOS Window appear to shown the model results as see in Figure 49. Note that you can hit any characters on the key-broad to pause the simulation and check the model results. If you want to exit the simulation hit the same key, if you want to continue run then hit any other key.
Figure 49 Running EFDC Window.
Go to Model Analysis Tab, select Model Calibration as shown in Figure 50. Click Define/Edit button to fill the Time Series Comparison form as Figure 51 then click OK button to finish.
After that click Plots button, a form of plot generation options appears for the user (See Figure 52). if the user check on two boxes, the EE will automatically generate plots and ASCII data file and they are stored in #calib_plots folder. The user can stop the process by press Esc button on the keyboard during automatic generation.
Otherwise the EE generate plot one by one.
Time Series Comparison and Vertical Profile Comparisons plots shown in Figure 53 and 54.
Figure 50 Model Calibration Window.
Figure 51 Time Series Comparison Form.
Figure 52 Calibration Plot Generation Options.
Figure 53 Time Series Comparison Plot.
Figure 54 Vertical Profile Comparison Plot.