Bentley OpenFlows FLOOD is a comprehensive tool for simulating and analyzing flood events, including dam break scenarios. OpenFlows FLOOD uses advanced numerical models to simulate the hydraulic processes involved in dam break scenarios. This includes the sudden release of water from a dam, which can cause significant downstream flooding. 

The general workflow for simulating dam breaks in OpenFlows FLOOD is to impose a surface inflow at the location of the dam. A hydrograph gives the surface inflow. The hydrograph can be constructed by the user (externally) or it can be automatically generated by a tool inside FLOOD. This dam break tool inside FLOOD can only be used for earth and rockfill dams. Please note that FLOOD does not consider mudflow during the simulation, it only considers water flows. 

To set up a dam break simulation you need to perform the following steps. First create a new model (new workspace, domain, terrain model file, etc.). 

1. Then you need to draw a line where the dam is located. To draw a line go to the Toolbox tab and click on 'Geometry Layer'. In the dropdown click on 'Create Lines Layer'. Keep in mind that when drawing a line, the line coordinates will be the same as the coordinate system used in the main map, except if a Bing maps layer is being used, in that case, the coordinates of the line will be written in geographical coordinates. If the model computational grid is in UTM coordinates, then the main map needs to be in UTM coordinates. Or if the grid is in a local coordinate system, the map needs to have the projection set to None. 

After that, you need to click on the tool as you can see in the 'Create Line Layer' dialog box as shown below -

Double-click to finish drawing the line once the line is placed on where the dam is located. 

3. Once the line is drawn, you need to save the file in Line File (*.lin) format, this is to make sure that the engine can read the file.

4. In the application, in the Toolbox tab go to 'Time Series' tools and click on ‘Generate Dam Break Outflow Hydrograph time series’. 

The tool generates a time series of flow rates representing the volume of water released from a dam over time during a breach event.

5. Input all the parameters as shown in the following image (From 'A' to 'H') -

6. With the line file and the hydrograph file, you can then set the surface inflow (discharge), right-click on your simulation (eg. Sim #1 shown below), and click on the properties.

7. After opening the Simulation dialog box, You need to select the 'Discharges' modules that is present in Available Modules. This will make the 'Discharges' modules active.

Finally, click OK.

8. Now click on Discharges _1.dat from Modules > Data Files as shown in the image below.

In this dialog box, you need to specify

- Type of Discharge

- Default value

- Variable Flow

- Time series file (generated in the 'Generate Dam Break Outflow Hydrograph time series' tool)

- Flow Column (The number will show where the flow is located)

Then, set up Location

Once the Geometry line is selected, then you can save and run the simulation. The flow that will be generated will be distributed along the line. All the grid cells along that line will have flow. As the flow discharge along the line does not have a direction assigned, it may be required to set the grid cells representing the reservoir as void grid cells. This assures flow can only go forward down the valley. You can use the tool Grid Data -> Edit Grid Data to void the cells upstream of the discharge line.