EFDC Restart Options are is under the Timing / Linkage. Right-mouse click on the Restart Options, the EFDC Model Restart Options form is shown in Figure 1. An explanation of the terms used, as well as how to use each option, is provided below in detail.
| Anchor | ||||
|---|---|---|---|---|
|
...
...
Figure 1. Model Restart Options
1. Output Options for Restart Files
EFDC Restart Options (Output) checkbox provides options for the creation of restart files. If the Use option has been selected then EFDC will create a RESTART.OUT file automatically. If Date Stamp is not checked then one file called RESTART.OUT will be created at the user-defined Output Frequency, overwriting the previous file each time. If Date Stamp is checked then a file called RESTART_YYYYMMDD_HH.MM.OUT is created at the Output Frequency for each EFDC sub-module being utilized.
DSI standard practice is to always select Use and set Output Frequency to 1 to be the same as the duration of the reference periods. The user must have this option turned on in order to use restart as this creates the files required for the restart. Date stamp can be left unchecked so that the file is written over each time it outputs.
EFDC Model Restart Options
Input Options for Restart Files
- Cold Start
Cold start is the normal start of a model run and EFDC will generate the new output files or overwrite the existing output files. This option is the default setting (Figure 2).
| Anchor | ||||
|---|---|---|---|---|
|
Figure 2. EFDC Model Restart Options: Cold Start
- Restart
The Restart is a previously available feature of EFDC and is applicable when a model has stopped prematurely and is not finished. The user can use it to restart from the point at which it terminated or some other point by selecting the appropriate restart file. In this case, there is a hard restart from the time selected. EFDC will create a whole new set of output files which the user will then need to merge later. Figure 3 shows the Restart option.
| Anchor | ||||
|---|---|---|---|---|
|
Figure 3. EFDC Model Restart Options: Restart
As noted that if Use is not checked for Output Options for Restart Files then EFDC will not create restart files. The restart function is still available but the user needs to load their own restart file.
...
Some of the restart files that are created include the TEMP.RST and RSTWD.INP files if temperature and wetting & drying are being simulated. The Dye Overwrite is a legacy option. If the checkbox is selected the dye concentrations in the restart file will be overwritten by DYE.INP file. This is useful when restarting a tracer study with a new initial condition.
- Continuation Run
A new option is ContinuationThe Continuation is a feature, whereby when restarting a model, EFDC+ can now move to the correct location in the EE linkage files and begin writing from the time the model stopped or from the time selected for restart in case of using date stamp. The settings for this restart option are shown in Figure 14.
A The Continuation Run is the same as the Restart option except that the output will append to an existing run and so is only applicable when there is already model output in the current model directory. If there is no output and a restart file then this option is not enabled. If no date stamp is used EE will display only one restart file without a date label which is the last restart file before EFDC terminated. To create the restart file the Restart Output should be set to continuous (i.e. N=1). EE displays the date range available for the continuation from the most recent binary file output in the Last Dates Datebox.
| Anchor | ||||
|---|---|---|---|---|
|
Figure 4. EFDC Model Restart Options: Continuation
| Anchor | ||||
|---|---|---|---|---|
|
Figure 5. Continuation Run Warning Message
The process for using continuation runs run is as follows:
- Before running the model ensure EFDC Restart Options (Output) Output Options for Restart Files is set/checked to Use. If Date Stamp is selected the user may continue from any snapshot as all snapshots are saved, not just the final snapshot. However, this is more memory intensive.
- Reload the model to update Last Date box. In this case (Figure 4) the model stopped at T = 218.
- Select the Continuation radial button (this is not enabled if the model is not reloaded). Then a warning message will be popped up as shown in Figure 5.
- Do not change the time of the start. Save the model in the same folder. If the user wants to save in another folder then they will need to manually copy the output to the new folder.
- Run the model and select overwrite.
The model will run from the continuation time and automatically merge with the prior output. This removes the necessity of the user having to merge runs as was required in earlier versions of EE. This option is different to the Append feature as it is now possible to restart a model at various user-defined times.
| Info |
|---|
Note: Whenever a new cold start is run the user should save the model in a new folder. This will prevent restart files from prior runs being available, in which case the Last Date may correspond to that prior run. |
Once the Restart Options is selected, it will be updated to the Model Restart Options report as shown in Figure 6.
| Anchor | ||||
|---|---|---|---|---|
|
Figure 6. Model Restart Options Report
Other options not discussed above include: Warm Start. This function allows the user to create the initial conditions for the model at a specified time. This is useful for diagnostic and sensitivity analyses, allowing the user to understand key processes in the system. A Warm Start option is described in Create Warm Start Model.
| Info |
|---|
The Restart and Continuation are called Hot Start. A Warm Start model is different from a Hot Start model because the momentum is not included. Therefore model would begin from a quiescent system as all velocity values are zero. Hot Start means using the existing output files to restart the model. |
Output Options for Restart Files
Output Options for Restart Files frame (Figure 7 )provides options for the creation of restart files. If the Use option has been selected then EFDC will create a RESTART.OUT file automatically. If Date Stamp is not checked then one file called RESTART.OUT will be created at the user-defined Output Frequency, overwriting the previous file each time. If Date Stamp is checked then a file called RESTART_YYYYMMDD_HH.MM.OUT is created at the Output Frequency for each EFDC sub-module being utilized.
DSI standard practice is to always select Use and set Output Frequency to 1 to be the same as the duration of the reference periods. The user must have this option turned on in order to use restart as this creates the files required for the restart. Date stamp can be left unchecked so that the file is written over each time it outputs.
| Anchor | ||||
|---|---|---|---|---|
|
Figure 7. Output Options for Restart Files