Open General Options by RMC on the Water Quality module and select General Options (Figure 1).
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Figure 1. Water Quality tab: General Options.
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 as shown in Figure 2.
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.
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Figure 2. Water Quality Point Source Loading
Time Series Data frame (Figure 3) allows users to edit the water quality data string by clicking the Edit button, or if they already exists, user can use the Import button to import water quality data series into model. In addition the Convert button allows users to convert data from Mass Loading to Concentration and vice versa.
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.
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Figure 3. Water Quality Point Source Loading
“Dry Deposition” and “Wet Deposition” are Dry Deposition and Wet Deposition are boundary conditions in the Water Quality module. The concentrations of water quality components from both boundary conditions are included in the EFDC+ computations. By default, these concentrations are initially set to zero and can be modified using EFDC+ Explorer. The following steps explain how to change the atmospheric deposition conditions.
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The user can also configure reaeration options (Figure 6) in this frame. The drop-down menu provides 5 options, including constant (WQKRO), constant + wind-generated, O'Connor-Dobbins (1958), Owens & Gibbs (1964), and Owens & Gibbs (modified). Each option will assign a default reaeration value.
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The saturation concentration of DO in water increases as pressure increases. This means that water at lower altitudes can hold more dissolved oxygen than water at higher altitudes. Allowance for the effect of elevation on the DO of the waterbody to DO, can be set in DO Saturation Options frame (Figure 7) The user can select different options from the drop-down list of the Formulation option. Options include Garcia and Gordon (1992), Chapra et al. (1997), and Genet et al. (1974). There are three options in the Elevation Adjustment drop-down, including to not use using the elevation adjustment, as well as the Chapra et al. (1997), and Zison et al. (1978) adjustments.
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