General Options (EEMS12)

Open General Options by RMC on the Water Quality module and select General Options (Figure 1).

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.

In the Atmospheric Deposition section, the user can modify the concentrations of different water quality components. To do this, LMC on the Dry Deposition or Wet Deposition buttons (Figure 4) then input non-zero values in the table displayed in which the water quality parameters are shown. Click OK to save changes.

Click OK to close the General Options option, then save the model.

Figure 4: Wet and Dry Deposition settings

EE will automatically initialize the water quality module using values in the code. However, it is often convenient to initialize a new model using data from another EFDC+ Explorer model with similar conditions. This is done using the Initialize WQ Parameters from File in the Miscellaneous frame as shown in Figure 5. This operation should only be conducted once at the start of the water quality model construction. This process overwrites all of the current model's settings.     

Figure 5.  Miscellaneous frame.

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.

Figure 6.  Reaeration options.

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, 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 not using the elevation adjustment, as well as the Chapra et al. (1997), and Zison et al. (1978) adjustments.

Figure 7. DO Saturation Options

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