The most recent release of InfraWorks 360 supports a fantastic flood simulation tool for coastal or inland flood risk assessment, thanks to a collaboration between Autodesk and Hydronia, LLC.
After installing a trial or licensed version of Hydronia's RiverFlow2D plugin for InfraWorks 360, you can simulate, visualize, and animate 2D flood events directly in your InfraWorks 360 models, and even save snapshots of different flood scenarios.
In this article, I will take you through the steps to prepare and run different types of flood simulation scenarios in InfraWorks 360 -- such as a coastal surge, a river or overland flow, even a flash flood event.
Thanks to the state-of-the-art shallow water equation model offered by RiverFlow2D for InfraWorks 360, you can accurately model inland or coastal flooding projects depending on the parameters you define.
1) For any flood simulation project, you will first need to download and install RiverFlow2D FS.
2) Next, open up your InfraWorks 360 model.
3) Click .
4) InfraWorks 360 prompts you to define a polygonal boundary for your flood simulation study area. Left-click to place each point, and double-click to complete the polygon. InfraWorks 360 will automatically re-mesh the terrain surface for the specified flood study area. ! Note: InfraWorks 360 currently only supports flood simulation animations based on terrain surface elevation, so 3D model objects such as buildings, bridge components, culverts, and drainage inlet intakes will not affect your flood simulation. However, you can modify the terrain in your model to approximate different features using Land Areas and Grading.
5) InfraWorks 360 prompts you to define the inflow location and outflow location. Click once to define the inflow start station, then drag your cursor along the boundary until you reach the desired end point for the inflow. Click again to place the inflow end point. Next, define the outflow location using the same procedure.
6) The Flood Simulation panel appears once you have defined a flood simulation study area boundary, inflow, and outflow. The inflow and outflows are marked with green bars.
8) Use the Flood Simulation panel to configure parameters for different types of flood scenarios.
Inflow Type: The inflow type represents how flood water enters and flows into your flood simulation area boundary. You can choose between a static or hydrograph inflow type. A static inflow uses a fixed consistent flow rate in cubic meters/second, based on the Q (flow discharge volume) value you define, while a hydrograph inflow instead has a flow rate that changes over time.
So, how do you decide how much inflow volume to specify for your simulation? For the most part, you want to base your simulation on historically or statistically predicted stream-gauge data (inland scenarios) or tidal/storm surge data (coastal scenarios). In the United States, there are some great resources for stream-gauge data publicly available through the USGS.
OK, now how do you decide whether to use a hydrograph or static inflow type? The answer here is dependent on your project needs. If you want to assess maximum possible flooding for a given area without regards to when the peak flooding may occur in your simulation, then you would probably just want to choose a static inflow type and specify a Q inflow volume equivalent to Q100, aka a 100-year-storm. However, if you want to instead visualize the entirety of a possible flood, from a base inflow rate, through a spike in inflow, and then back down to a more level inflow rate (which would create a flood simulation that resembles a storm surge or a flash flood), you'd instead want to choose a hydrograph inflow type. If you do specify Hydrograph as your inflow type, the Flood Simulation panel prompts you to specify units of measurement and select a data file that defines your hydrograph inflow. You can create hydrograph inflow files on your own using a simple text-editing application such as Notepad.
Note: As a rule of thumb when creating your own hydrograph inflow files, remember that the first line must have exactly one integer that represents the number of intervals in your simulation, followed by that number of rows, with exactly two real numbers per row. Each pair of numbers should be separated by one or more spaces, as they represent time and associated inflow discharge volume. The time is assumed in hours and can be any whole number or decimal number. Do not include units of measurement in a hydrograph inflow file.
For example, if I wanted to create a hydrograph inflow file for a flash flood event, I would specify a simulation time that is under 5 hours total (that is the definition of a flash flood -- a flood that lasts under 5 hours), and populate different inflow rates at different intervals. For example, if I wanted to create a flash flood simulation in Albuquerque, New Mexico that lasts 4 hours, sampled at intervals of 15 minutes, I would therefore need to create a hydrograph inflow file that has 16 rows of time v. flow data arranged to represent a sudden inflow surge that dissipated rather quickly. Using USGS data to verify flow rates for my project site in Albuquerque, I would create a hydrograph inflow file that looks like this (you can also watch a video of this exact example, here):
Outflow Type: The outflow type represents how flood water exits your flood simulation area boundary. You can choose between a Uniform or Free Flow outflow type depending on how you want your outflow behavior to function in regards to the terrain elevation in your model.
- Free Flow: There is no restriction on the outflow as it leaves the simulation area through the outflow boundary. Derivatives of water surface elevations and velocities will be assumed at zero.
- Uniform: If you choose Uniform, you will be prompted to specify a slope condition. Choose Average slope condition to use an outflow rating table that is based on the computed average slope entry condition, calculated every .05 meters starting from the lowest bed elevation in the cross-section up to 50 meters above the highest bed elevation in the section. For each time interval, the flood simulation will impose water surface elevation that corresponds to the boundary discharge interpolating on the rating table. Choose User Defined and enter a slope value in the Slope field if you want to input a specific value for the boundary bed slope condition. For example, if you manually enter a User Defined slope condition with a slope of -999, the model will calculate the average bed slope perpendicular to the boundary line.
Triangle Size: The size of triangles in your flood simulation area mesh.
- Input a value to change triangle size. By default, triangle size is set to 20.0 m. Using a smaller triangle size increases the total number of triangles in the flood simulation mesh, which can increase the accuracy of your simulation but will require longer processing times. Triangle sizes between 1.00 and 999.00 meters are supported.
Manning's n: Every triangle in the simulation area mesh is assigned a manning's n-value which represents the roughness, or friction-resistance of the materials that flood water passes over. Water will travel at different speeds over different materials, such as a sandy river bottom vs. a rocky shoreline. So, *if* you have previously added coverage areas to your flood simulation study area, using a Distributed manning's n method will allow you to increase the accuracy of your flood simulation .
- Uniform: by default, the manning's n-value is set to .02 for every triangle in the flood simulation area.
- Distributed: if you have included coverage areas in your model to modify terrain or capture information about existing surface materials, any triangle in the flood simulation that overlaps a coverage area will be assigned a manning's n-value based on the materials used in that coverage area style. These rules are mapped in the MaterialMapping2RunoffManningCoeff.clp file within C:\ProgramData\Autodesk\InfraWorks 360\Resources\Standards\Drainage\Common\Rules. You can edit this CLP file in a text-editing application. See: To modify default manning's coefficient (n) values in the .CLP file .
Simulation Time (hrs): Specify a time in hours for the entire simulation. If you created a hydrograph inflow file for your Inflow, you will want the simulation time to match the total time defined by your hydrograph.
Interval (min): Specify a time in minutes for the length of each interval in your simulation. Increasing the number of intervals provides more granular time-tracking of flood events, but can also increase processing time for your flood simulation animation. If you created a hydrograph inflow file for your Inflow, you will want the number of intervals time to match the total time defined by your hydrograph.
9) Now click Run Simulation. InfraWorks 360 passes the information to Hydronia for computation, and will display the Animation Player in-canvas when it is has finished processing.
10) Click play in the Animation Player to run the flood simulation animation within InfraWorks 360.
11) If you specify a different animation theme type, you must replay the animation for the new theme to take effect. You can choose between elevation, depth, and velocity themes for the flood surface animation. If you choose a velocity theme, you can also display directional inflow and outflow velocity arrows.
12) You can also create a flood snapshot of any static moment in your flood simulation animation, and show/hide visibility of your flood snapshot in-canvas at anytime.