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Figure 1. Water Quality Tab: Kinetics.
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Figure 2. Kinetics Computation Options.
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. 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 3. Miscellaneous frame.
EFDC+ allows users to assign any of the water quality parameters for water column zones. Check the box Use Zones for Kinetics and then click on the Define Zones button brings up the Apply Cell Properties via Polygons form (see Apply Cell Properties via Polygons). The user must first enter the maximum number of desired zones in the Number of Kinetic Zones box. This number may be changed at any time during the model building process.
Figure 43. Define Zones.
Zones are assigned by the water column layer and cell, so it is possible for the same cell to have more than one zone assigned to it if KC>1. The parameters that vary by zone are shown in the Water Quality Kinetics frame. There are three groups of parameters that can be varied by zone: Kinetics, Settling, and Algal Dynamics. For each group, the use of zones or not is separately controlled using the checkboxes for that group. The specific parameters for the Current Zone for each group are modified by clicking on the Modify button. When the kinetic zones are enabled, these values are used in preference to the default values that will still be displayed under COD parameters under the Nutrients tab.
Figure 54. Water Quality Kinetics.
The user is able to configure reaeration options in this frame. There are five types of reaeration are presented in the drop-down menu including constant (WQKRO), constant + wind-generated, O'Connor-Dobbins (1958), Owens & Gibbs (1964), and Owens & Gibbs (modified). The Reaeration Constant will be assigned by default when the user selects the option. Note that Use Zones for Kinetics check box must be selected if changes are made here.
Figure 65. WQ Zones: Kinetic Parameters.
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