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EFDC allows users to assign many of the water quality parameters for water column zones. Clicking 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 can be changed at any time during the model building process.326px
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 frame Water Quality Kinetics. There are three groups of parameters that can vary by zone: Kinetics, Settling, and Algal Dynamics. For each group, the use of zones or not is separately controlled using the check boxes 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.
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