Boundary Group Utilities

Owned by Duy Pham
Last updated: 07 Sept, 2017
8 min read

The Boundary Group Utilities contains Edit/Review, View Loadings, Import HSPF, and Check shown in Figure 1.

Figure 1  Boundary Group Utilities.

Edit/Review Boundary Conditions

The Edit/Review button provides access to the general Boundary Conditions Definitions/Groups group form shown in Figure 2. This form provides a listing of all the defined boundary groups by group ID. The list of boundary groups can be sorted by ID or listed in the order they are defined in the EFDC.INP file. In the top frame, Number of Boundary Groups, the number of the currently defined boundary groups, by type, are displayed.

A method to quickly define one or more boundary groups (where boundary condition details are to be added later) is available using the Batch Define button. This approach uses a P2D file with one or more polylines/polygons in a single file. If a polyline is open (i.e. the 1st and last point are not the same) EFDC_Explorer will select all of the cells the line intersects as one group. If the polyline is closed (i.e. the 1st and last point are the same) EFDC_Explorer will select all of the cells whose centroids are inside the polygon as one group.

As the user selects a boundary group from the list, summary information about the boundary group and its linkages to various boundary forcings is displayed. To edit a boundary group the user can double click on the group ID or press the Edit button.

When the user RMC on a group ID pops up a menu that allows the user to do the following options ( see Figure 3)

Edit: Modify the select group BC

New: add a new boundary group. When the user select New, a form will appears as shown in Figure 4. Put a BC ID and click OK button. Then a form of boundary type allows the user to assign to the boundary group. There are eight boundary types (Figure 5), the user just enter the number corresponding to boundary type ( e.g if the boundary type is flow, just enter 1) then click OK button.

Delete Group: delete the currently selected group only

Delete Group and Flows: delete the currently selected group and its flow series

Delete Group, Flows and Concentration Series: delete the currently selected group with its all associated series

Set Uniform Layer Flows: uniform flows by layer for the selected BC group

View: plot the time series of the primary forcing

When using the time series plotting function from this tool, the model simulation start and end times define the minimum and maximum date range. If the time series is longer, the entire time series can be viewed from the Time Series editor.

The Momentum Corrector for BC Cells Located on the Model Edge is used to set the appropriate model response for the EFDC_DSI or EFDC_GVC models. It should be 0 for the former and 1 for the latter, but may set to some number between 0 and 1.



Figure 2  Boundary Condition Definitions/Groups.


Figure 3  Options when RMC on a Boundary Group.


Figure 4  Add a new Group BC.

Figure 5  Assign Boundary Type for a Boundary Group.

Import HSPF Data

The Import HSPF button provides access to the import function for the Hydrologic Simulation Program in Fortran (HSPF) (Bicknell et al., 2001). This is a hydrologic watershed modeling tool that is commonly used to predict flows and some water quality parameters. If this tool is used to predict the flows in a basin/watershed in which the EFDC model is being applied, then these results can be imported as boundary conditions for EFDC.

In addition to HSPF results, the Import HSPF tool can import any time series data whose flow and or water quality parameters are contained in columns (i.e. ExcelTM type csv or tab delimited data). The dates can be Julian or Gregorian calendar dates. If Julian dates, the Base Date used for the imported time series should be the same as that used in the EFDC project.

The import tool, shown in Figure 6, works by linking the time series/HSPF files to specific boundary groups. The only groups that can have HSPF data linked to them are flow boundaries. Each group can have its own HSPF file and import options. Flow, temperature, solids and water quality are optionally selected in the Import Parameters Frame.



Figure 6  HSPF model results import utility.


To view each parameter's options, select the corresponding radial option in the Import Parameters frame. When the parameter is selected, the options frame is shown to allow the user to:

  • Select whether to import that parameter for the current group using the Import check box. To activate all the groups for the current parameter, press Ctrl-A.
  • Set the column which contains the data. Column 1 is the 1st column after the column offset.
  • Define a conversion factor to convert whatever units are in the file to the appropriate units for EFDC (i.e. m3/s for flow, °C for temperature and mg/l for solids, mg/l for water quality and MPN/100 ml for fecal Coliform). In addition, the conversion factor can be used to split a single number into its sub-components. For example, total organic nitrogen from and HSPF run can be split into the dissolved and particular (refractory and labile) nitrogen components.
  • Select which time series number to import the series into. The first time the user imports an HSPF file, the Import into Existing checkbox should not be checked. EFDC_Explorer will import the series and add a new series ID and assign it to the appropriate boundary group. However, if the HSPF results are being re-imported or updated based on new HSPF results then the user will want to import the data into an existing EFDC series. EFDC_Explorer uses the current boundary information to assign the series number to import to, but the user can change it if needed. When the Import to Existing checkbox has focus, pressing Ctrl-A will cause the all of the boundary groups to use the same option as the current group. Importing into an existing series does not overwrite the entire series, rather it inserts into the specified series between the Begin and End dates.
  • The # of Cols in the Column Offset frame provides a global column offset. This may be needed if there is an "E" in column 1 (some HSPF export series use this) or some other information in columns before the date column. EFDC_Explorer uses the date/time columns as the 1st columns from the left, after accounting for the column offset.


The solids are a special case. Along the rows the solids classes for HSPF are displayed. In the 1st grid column ("Col") the user specifies the data column number that contains the clay, silt and sand. Then the user assigns weights or factors to each grain size class modeled in EFDC to the data columns. In this manner the user may combine HSPF sizes into whatever EFDC class they desire. If the class weights totaled for each row add up to 1, then the same mass that is predicted by HSPF will be input to EFDC. It is possible to assign more of any HSPF size class to EFDC than HSPF computed by using weights that add up to more than one. This same approach is true in reverse as well.


The period of extraction from the HSPF files is controlled by the Begin and End dates specified in the input boxes located at the bottom of the HSPF preview pane.
The HSPF File preview pane shows the some of the data from the HSPF File for the user's reference. It can be seen in this example that the flow is contained in column 2 (0.01 cfs) and dissolved oxygen is contained in column 7 (5.58 mg/l).


EFDC_Explorer interprets a calendar date using the Windows date settings. This is important if files are processed on different computers with different date settings (i.e. files from Asia being processed on computers in America). The issue here is if the dates are ambiguously formatted as MM-DD-YYYY or DD-MM-YYYY. A date of "01-02-2008" can be interpreted as 01-Feb-2008 or 02-Jan-2008, depending on the windows date format. To correct a date interpretation problem between windows configurations, check the Data is not in System Date Format checkbox. This simply reverses the order of the first two date fields.


The delimiter must be specified as space, tab or comma. The correct delimiter must be selected before processing the linkage.


The time series/HSPF File that will be linked to the current boundary group is shown in the HSPF File Information/WDM Formatted frame. The user should Browse to the file. If the same file will be used for all boundary groups the user may press Ctrl-A when the HSPF File field has focus to assign the same file for all the groups.


To actually link the HSPF data to the EFDC boundary condition group(s) the user must press one of the following:

  • Apply to Current Group: This button processes all the parameters designated for import for the currently selected boundary group only. Only those parameters selected for import are processed.
  • Apply for All Groups: This button processes all the parameters designated for import for every flow type boundary group. All the options defined for each boundary group are used.


Groups are added and deleted by setting the focus to the group list and then pressing "INS" or "DEL" as is appropriate. If deleting a group, make sure the correct group is selected.

Check Boundary Conditions

The Check button runs a series of checks all the currently defined boundary conditions. Some of the validation checks include:

  • I & J cell indexes point to active cells
  • Table series are valid
  • Matching head/concentration cells for open boundaries,
  • Etc.


If errors are found they are reported and can be copied to the clipboard for pasting into other reports.

View Loadings

The View Loadings button brings up the loadings option form shown in Figure 7. This form shows the valid model timing (based on the model start and end times) and allows the user to select a date range to process within the model dates. The parameter to view is also shown. This list varies, depending on the computational options.


When the View button is selected, EFDC_Explorer computes the mass loadings time series for all of the flow type boundary groups selected and displays them in a plot. The units displayed will vary, depending on whether the user is configured to display metric (metric tons (MT) per day) or English (tons (2000 lbs.) per day). Figure 8 shows an example of mass loading (by group) for Total Phosphorus. To then compute the total mass loading for the time period displayed on the plot, press Ctrl-I to integrate the series (see Sect 9.2 for more details). Since the time units are days and the mass loading is MT/day, entering a 1 for the conversion factor results in the mass loading being reported in metric tons. Note that the user is now able to use concentration loadings rather than mass loadings as discussed in Section 5.15.5.



Figure 7  View loadings options form.


Example of mass loading plot for Total Phosphorus (TP)

Figure 8  Example of mass loading plot for Total Phosphorus (TP).