Water Quality Kinetics

Owned by Kester Scandrett
Last updated: 26 Sept, 2017
2 min read

The WQ - Kinetics tab is shown in Figure 1. Some of the user options include setting the Global Kinetic Options from one of several modules. For the EFDC_GVC version, the standard kinetic model is contained in Module 3 (ISWQLVL=3). While the other kinetic modules may be used (with care) when using the EFDC_GVC version in the standard sigma mode, if the GVC option is selected ONLY module 3 works. For the EFDC+ version, the standard full kinetic module is Module 1 (ISWQLVL=1). Once the kinetic option has been chosen the user still needs to select which parameters will be varied/simulated within the selected kinetic option. Clicking the Params button brings up the list of parameters whose simulation (i.e. advection and dispersion) can be switched on or off. However, even if a parameter is not simulated, since it is still part of the kinetics, the IC concentration is used for all of the kinetic calculations.


Figure 1  Water Quality Tab: Kinetics.

EE will automatically initialize the the water quality sub-model using the Access template file (EFDC.MDB). 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.

EFDC allows for water column zones for the assignment of many of the water quality parameters. The WQ zones can be set using the Define Zones button or can be set in ViewPlan (Water Column/Wtr Quality then check WQ Zones checkbox). 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.

Zones are assigned by 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.
The Fecal Coliform Decay button allows the user to set the decay rate and temperature effect constant.