Getting Started with the QUAL2K Web Wizard

The engine guides you through the model inputs in 14 steps, following the published QUAL2K / QUAL2Kw framework. Each step covers one part of the model, from project metadata to the run and the results. If you already have a QUAL2Kw workbook, you can skip the typing: see Import a QUAL2Kw workbook.

The 14-Step Wizard

Figure 1: Wizard steps (the advanced ones can be left at their defaults)

Step 1: Open the Engine

Open the prediction engine. You can run 2 simulations without an account; a free account gives 5 a month, cloud save of your models and the auto-calibration. Your work in progress is kept in your browser until you save it.

Step 2: Enter Project Data

Card 1 (Project Setup) captures the river name, simulation date, time zone and calculation step size. The default 11.25-minute time step works for most cases.

Step 3: Define Reaches

Card 2 (Reach Definition) is where you define the river geometry. Each reach requires:

Name — identifier for the reach (e.g., "PR1", "VPR1")
Downstream Distance — cumulative distance from headwater (km)
Upstream and Downstream Elevation — for slope calculation (m)
Manning's n — roughness coefficient (typically 0.03–0.15 for natural streams)
Bottom Width — channel bottom width (m)
Side Slopes — trapezoidal channel side slopes (horizontal:vertical)

Step 4: Set Headwater Boundary

Card 3 (Headwater) defines the upstream boundary condition: flow rate (m³/s), water temperature (°C), dissolved oxygen (mg/L), and concentrations for all 15 water quality constituents.

Step 5: Add Sources (Optional)

Cards 4 and 5 handle Point Sources (wastewater discharges, tributaries) and Diffuse Sources (nonpoint pollution, groundwater inflow). These are optional for simple headwater-only models.

Step 6: Configure Kinetics

Card 6 (Kinetic Rates) contains the first-order reaction rate constants for all water quality processes. Default values from the QUAL2K literature are pre-filled. See the BOD Decay and DO Balance pages for detailed explanations of each parameter.

Step 7: Import Data (Alternative)

Instead of manual entry, you can import a QUAL2Kw workbook (.xls, .xlsx, .xlsm) with Import QUAL2Kw workbook, or a saved project with the Import JSON or Import CSV buttons in the bottom toolbar. JSON files provide exact state restoration; CSV files enable bulk data entry from spreadsheets.

Step 8: Run the Simulation

Card 14 (Review & Run) shows a summary of all inputs and provides the simulation button. Clicking "Run Simulation" sends the wizard state to the cloud engine. Small models return in a few seconds, large ones can take a few minutes, and a run is stopped at 300 seconds.

Step 9: Review Results

After a successful run, the results open in the Results step. You can view:

Hydraulics Summary — velocity, depth, width, area, travel time, and reaeration for each reach
Water quality - the daily mean, minimum and maximum of each constituent at each reach, with temperature and pH
Charts - profiles along the river with your observed data and water-quality objectives

Download the results as CSV or as a PDF report, or save the model to your account.