How can I model a "2D simulation", showing the extent of flooding / overflow above the road curb? For example when overflow spills over a gutter and into the surrounding area, I want to see how far the flooding extends.
Can we see this urban flood map in 3D to know the "spread" of runoff extending beyond the road?
Enhancement # 409346
A 2D simulation can be accomplished with OpenFlows FLOOD (formerly known as MOHID Studio from ACTION Modulers - does not use Bentley licensing, contact Support for a license key). Existing SewerGEMS/CivilStorm models can be imported and combined with a terrain surface to perform a 2D simulation of a hydraulic model. A separate article with details will be available soon. If you are interested in OpenFlows FLOOD, please contact your Bentley Account Manager.
See also: Integrating SewerGEMS or CivilStorm with OpenFlows Flood for 2D simulations
Tighter integration between OpenFlows FLOOD and SewerGEMS/CivilStorm is planned for the future. In the meantime - for SewerGEMS or CivilStorm, usually this level of detail is not needed, as you would typically want to be alerted to cases where the top of the gutter is exceeded and then address the problem accordingly. You can check to see (using a query or color coding for example) if the calculated gutter depth exceeds the depth over which water would reach the top of the gutter (or middle of road) and "spill" over to the other side. If the depth reaches this value, you would likely need to take some action, or note that it is a problem area in your drainage system.
Within SewerGEMS or CivilStorm, you can also perform quasi-2D modeling using a network of 1D channels and/or ponds. The downstream trace query can show you where overflows would flow on a terrain model. Once you know that you can set up channels along the flow paths to analyse the flows.
Another approach, for catchbasin overflow, would be to use the Ponded Area option for the catchbasins' "Surface Storage" option. However, this can be challenging for the numerical solver. Some of these challenges are described here: Modeling surface ponding for overflow above multiple inlets
Integrating SewerGEMS or CivilStorm with OpenFlows Flood for 2D simulations
Flood Modelling using SewerGEMS
Digital Terrain Models and Downstream Trace
Modeling surface ponding for overflow above multiple inlets