Overview
This lecture covers the setup and key considerations for water quality modeling in InfoWorks ICM, focusing on point source, non-point source, and two-dimensional methods.
Point Source Water Quality Modeling
- Point source modeling requires an inflow file and a pollutograph associated with a specific network node.
- The pollutograph defines concentrations of constituents like nitrogen, phosphorus, sediment, BOD (biochemical oxygen demand), and silicon.
- Hydrogen sulfide modeling requires BOD to also be included.
- Enabling "use qm" is necessary to run water quality simulations.
- Results can display dissolved BOD and sediment fractions at various nodes.
Non-Point Source Water Quality Modeling
- Non-point source data is managed within the subcatchment’s build up and wash off land use tabs.
- Two main build up and wash off models: Enterprise and SWMM methodologies.
- SWMM method uses sweep intervals and removals to manage pollutant accumulation and removal.
- Model parameters include maximum buildup and wash off efficiency for different land uses.
Two-Dimensional (2D) Water Quality and Sediment Modeling
- 2D sediment modeling uses initial condition sediment areas defined by zone and type.
- Initial condition objects must match the corresponding zone ID for the simulation.
- Water quality can be modeled for dissolved constituents and sediment fractions (e.g., SF1, SF2).
- Erosion and deposition effects, as well as 2D bed load options, can be toggled within the model setup.
- Simulation results can be visualized across a results line for constituent concentrations.
Model Parameters and Configuration
- Water quality and sediment parameters are set under Model Parameters in the software.
- Key parameter settings depend on modeling approach (erosion, deposition, bed load, etc.).
- Input values must be tailored to match the desired modeling method and scenario.
Key Terms & Definitions
- Point Source — A single, identifiable source of pollution, such as a pipe or outlet.
- Non-Point Source — Diffuse pollution sources, typically from land runoff, affecting water bodies.
- Pollutograph — A time series defining pollutant concentrations at a node.
- BOD (Biochemical Oxygen Demand) — A measure of organic material requiring oxygen to decompose.
- SWMM — A water quality modeling methodology focused on stormwater management.
- Build Up and Wash Off — Methods describing pollutant accumulation on surfaces and their removal during runoff.
- Initial Condition — Model object that sets starting concentrations or states for a simulation.
Action Items / Next Steps
- Review InfoWorks ICM Help Menu for detailed parameter definitions and methodologies.
- Set up model-specific pollutographs and inflow files for planned simulations.
- Define initial conditions and adjust water quality parameters as needed for your scenario.
- Explore reference materials for advanced sediment and erosion modeling techniques if required.