In HEC-ResSim, most of water quality parameters are the coefficients and rate constants used in the calculation of kinetic source and sink terms of constituents. These coefficients and rate constants, as well as other related water quality (WQ) parameters, are defined in the WQ Parameter Set Editor. However, a Geometry dataset (Chapter 4) and at least one WQ Constituent Set (Chapter 5) must be created before a user can define all parameters in a WQ parameter set. These two pre-requisite datasets are the Geometry (Chapter 4) and at least one WQ Constituent Set (Chapter 5). The WQ Parameter Set Editor (Figure 6.1) enables the user to create one or more WQ parameter sets and to define the model parameters in the selected WQ Constituent Set (Figure 6.1). The water quality parameters are determined from selecting the libraries and constituents. As described in Chapter 5, the water quality libraries include the following three libraries: Temperature, NSMI (Nutrient Simulation Module I), and General Constituent Simulation Module (GCSM) libraries. Each library simulates a set of constituents (see Appendix B).
Figure 6.1 – WQ Parameter Set Editor – Example
The water quality parameter values are defined globally or with a base value, and if the selected Geometry (Figure 6.1) dataset (refer to Chapter 4) contains regions, then the parameter values can be defined by water quality region. The prerequisites for completing a WQ parameter set are the creation of a Geometry dataset (Chapter 4) and at least one WQ Constituent Set (Chapter 5). The WQ parameter set is not used in the creation of any WQ datasets. Once completed, this parameter set is used during the water quality model compute.
