๐๐ Water Quality Simulations (InfoWorks) ๐๐
When diving into water quality simulations within an InfoWorks 1D network, the primary objective is to emulate the sediment accumulation in the network and track the movement of sediment and contaminants through the drainage system during a precipitation event. ๐ง️๐ฌ
For insights on 2D network water quality modelling, refer to the ๐ "2D Water Quality Simulations" section.
The success of pollutant modelling hinges on a robust set of starting conditions. Thus, it's pivotal to conduct an initialisation simulation for a substantial period before the main water quality event simulation. ๐๐ The terminal state of this initialisation becomes the starting point for the main model. To get a deeper dive into initial conditions, see the "Initial Conditions" section.
Typically, the simulation setting up the model's initial state will mirror a dry weather flow scenario, but sometimes it might encapsulate a rain event. ๐ฆ️
๐ Stages to Execute a Water Quality Simulation ๐
Setting Up Data ๐
- Configure water quality-specific parameters for the network.
- Incorporate pollutant details for Trade and Wastewater Events.
- Implement Pollutographs to signify pollutant inputs tied with inflow or level hydrographs.
- Choose the build-up/washoff model for simulations, considering whether to use Innovyze or SWMM models.
- Ensure sediment features, especially diameter (d50) and specific gravity, for each sediment fraction are defined.
Setting Initial Conditions - Initialisation Run ๐
- Establish the network's starting state, either through a dry weather flow simulation or a buildup period for surface sediment. This is crucial for the subsequent modelling runs.
- Execute an initialisation run, which often is a dry weather flow run.
Carrying Out Simulations - Modelling Runs ๐ง️
- Post the configuration of the initial state, actual modelling runs can commence.
- For these runs, you'll need to incorporate one or more rainfall events and ensure all other parameters remain consistent with the initial run.
Viewing Results ๐
- Analyze water quality outcomes similarly to a regular hydraulic simulation. There are extra results fields available explicitly for water quality simulations.
๐ Discussion & Conclusions ๐ Determining which method to use for inlet simulations is crucial. If water is flowing smoothly along a road, a flow efficiency relationship is recommended. However, if there's ponding at the inlet, a head discharge relationship becomes vital. ๐ง๐
For sag inlets, oscillations may be observed as they transition between weir and orifice equations. This can potentially destabilize models, especially if the transition occurs at shallow depths. ๐ง๐
References: ๐
- "Urban Drainage Design Manual", focusing on Pavement Drainage and Drainage Inlet Design.
- The Highways Agency's "Design Manual for Roads and Bridges".
- City of Fort Worth's "Storm Water Management Design Manual". ๐
Remember, consistent data and an understanding of the network's characteristics are vital for achieving accurate and meaningful water quality simulations! ๐ง๐๐
