Boundary Conditions - WQ

EFDC+ Explorer provides the ability to define water quality boundary conditions with load concentrations rather than mass-loading files. The user can select various options for Water Quality Point Source Loading Option is shown in Figure 1 .

Figure 1.  Water Quality tab: Boundary Conditions.

The Water Quality Point Source Loading Option provides a drop-down table with the following three options: Use Constant Point Source Loads, Use Time Variable Point Source MASS Loadings, and Use Time Variable Point Source Concentrations.

EFDC+ Explorer previously only used the larger mass-loading files. The new Load Concentrations option provides the user with smaller files and greater control. When the user selects an option different from that previously selected, EFDC+ Explorer informs the user of the current BC and asks whether they want to switch to the new option. If the user responds affirmatively then EFDC+ Explorer will convert and save out the option selected.

Users can either overwrite or append a new water quality time series by clicking on Import & Convert WQPSLC.INP (Override) or Import & Convert WQPSLC.INP (Append) buttons, which is a WQ Point Source concentration file, with a concentration in kg per day. The WQ BC load concentrations rely on two new input files: WQPSLC.INP and WQPSL.INP. Note that WQPSL.INP is an EFDC+ Explorer file not used by EFDC. It is often a very large file.

When the user returns to edit the water quality tables and series in the External Forcing Data tab, EFDC+ Explorer displays all 21 WQ parameters. In the MASS Loadings option these parameters are depth-averaged and not layered, and so are vertically constant. However, after converting to concentrations loadings, the user is informed that the values have been converted, and now are now stored layer by layer. Initially, these values will be an average as calculated by EFDC+ Explorer, but the user can now specify certain layers and assign new values as required.