Setting up and running a simulation in ResSim is explained in detail in Chapter 14 of the HEC-ResSim User's Manual. Below is an overview of the steps to initiate and analyze a water quality simulation:

  1. In the Simulation module, begin by selecting a predefined Water Quality Alternative. This involves specifying the alternative that contains the necessary datasets, including geometry, constituent set, parameter set, initial conditions, boundary conditions, and mixing coefficients.

  2. Specify the Start Date, Lookback Date, and End Date for the simulation. These parameters determine the time window during which the water quality model will run.

  3. Once all settings have been configured, run the Water Quality computation.

After successfully completing the water quality simulation in ResSim, various output visualization and analysis options are available:

  1. Water Quality Plots:
    ResSim offers several types of plots to display the results of the water quality simulation:

    • Time Series Plots: Show changes in water quality over time for specific sites or constituents.
    • Profile Plots: Display variations in water quality along a spatial dimension (e.g., along a river reach or across the watershed).
    • Color Contour Plots: Provide a spatial visualization of water quality variations across the entire simulation domain.

    Observed water quality data can also be overlaid on these plots, providing a comparison between modeled and real-world measurements.

  2. HDF5 File Outputs:
    All water quality results are saved into an HDF5 file, which contains detailed temporal and spatial data. This file can be used to visualize:

    • State Variables: Values representing water quality conditions at different points in time.
    • Derived Variables: Additional data calculated from the state variables, such as concentrations or fluxes.
    • Pathway Fluxes: Information on the movement of constituents through the system.

    The HDF5 file format supports efficient data storage and analysis, enabling users to extract and analyze specific information as needed.

  3. Water Quality Output Log File:
    In addition to graphical outputs, ResSim generates a water quality output log file (*.wqEngineLog). This file provides detailed information about the simulation process, including:

    • The simulation progress.
    • Warnings or errors encountered during the simulation.
    • Information for debugging and troubleshooting any issues with the water quality model.