OpenFlows FLOOD

Frequently Asked Questions

What is FLOOD?

FLOOD is flood modeling software for analyzing and mitigating flood risk in urban, riverine, and coastal areas. Using spatially distributed numerical models, users can quickly simulate all hydrological and hydraulic processes to support emergency planning and green-initiative design. Apply a multi-scale 1D/2D approach to support flood early warning systems (FEWS).

How much does FLOOD cost?

A practitioner license of OpenFlows FLOOD costs $14,644 USD. Prices vary per region. While there are various types of licensing available, a common choice is the 12-month practitioner license offered through Virtuosity, Bentley’s eCommerce store. When you purchase through Virtuosity, you get a Virtuoso Subscription. This means you get the software and “Keys” (tokens) to redeem for customizable training, mentoring, and consulting services.

What is the difference between FLOOD and HEC-RAS?

All the equations and numerical methods, and source code from the 2D flood model (MOHID) is available online. This is a collaborative, free, opensource “model.” HEC-RAS is free, but not open-source which means that an advanced user is not able to check source code or modify it.

FLOOD numerical solver (MOHID) was analyzed for comparison with a benchmark study from UK Environment Agency. This methodology has been adopted as the world reference for benchmarking 2D flood modeling. FLOOD results are compatible with most solutions.

FLOOD can be used as a single tool for an integrated 2D flood model, while HEC-RAS does not have direct rain-on-grid, infiltration, or evapotranspiration. You would need an additional tool called HEC-HMS for other hydrological parameters and processes.

You do not need to specify the area or time of concentration for a catchment in FLOOD. Digital Surface model together with 2D calculation (Saint-Venant and Manning-Strickler equations) will do this for you. Additionally, you do not need to enter depression data as the 2D surface contains topographical data which is considered in runoff estimation. FLOOD has tools to remove depressions from the ground surface if required.

FLOOD is a full GIS-enabled GUI. You can handle GIS data inside (e.g. Bing Maps; shapefiles, RASTER files, etc.), including results visualization. HEC-RAS visualization needs to be handled in separate tools or 3rd party software licensing (e.g. such as ArcGIS).

Does FLOOD integrate with other products?

As part of Bentley Systems, FLOOD has an added value of being integrated into a broad portfolio and roadmap of interoperable and collaborative technologies and products across multiple disciplines and competences. Some unique examples of the advantages of being integrated into the Bentley software environment:

• FLOOD can run based in DSM generated by iTwin Capture Modeler, which uses photogrammetric techniques applied to surveys in LIDAR or images from cameras to generate reality mesh models.
• You can seamlessly have 4D visualization of FLOOD output results in Bentley’s LumenRT, integrating life-like digital nature into simulated infrastructure designs, and create high-impact visuals for stakeholders.
• FLOOD can integrate with Bentley’s OpenCities Planner, a cloud-based service that enables visualization of 2D, 3D, and GIS data in a city-scale digital twin where you can design, visualize, and communicate projects from large-scale city developments to detailed architectural design.
• You can use FLOOD outputs to feed mobility modeling and accessibility in Cube software.
• You can design a road using OpenRoads ConceptStation, and then generate the surface mesh model and easily ingest it in FLOOD.
• You can use FLOOD projects to implement and configure flood early warning / forecasting systems, through the application of ACTION Server product.
• Integration with OpenFlows SewerGEMS project allows you to use the designed 1D network and to run 1D:2D model approach inside FLOOD. FLOOD improves your efficiency for setting up 2D flow models, running, post-processing and visualizing the results.  It is the only tool capable of doing the full modeling cycle with all the advanced tools for handling models and results. FLOOD can run coupled 1D (natural or artificial channels, in both surface and subsurface) and 2D (overland flow) models.
• FLOOD can also be coupled with SWMM to run 1D and 2D models but integration with OpenFlows SewerGEMS provides a smoother experience.
• Being a full GIS system, FLOOD can cover your needs to consume, manipulate and generate data and model results in multiple formats (e.g. shapefiles, GDAL RASTER files, Google Earth KML/KMZ, TIN files, INP drainage network models from SWMM). This allows you to establish input / output data fluxes and interoperability across an array of software products.

What are the differences between FLOOD, OpenFlows CivilStorm, OpenFlows SewerGEMS?

There are differences in the methodology adopted by FLOOD and storm-sewer products such as CivilStorm and SewerGEMS. Using CivilStorm or SewerGEMS, you must explicitly provide data in the form of specific parameters such as surface roughness values, time of concentration and depression data (if the surface has areas of ponding). All these factors are automatically considered using FLOOD.

You do not need to specify the area or time of concentration for a catchment in FLOOD. Digital Surface model together with 2D calculation (Saint-Venant and Manning-Strickler equations) will do this for you. Additionally, you do not need to enter depression data as the 2D surface contains topographical data which is considered in runoff estimation. FLOOD has tools to remove depressions from the ground surface if required.

Runoff generation and other processes are complex. With FLOOD, it is primarily generated based on the 2D surface terrain and the modules selected to run. The runoff hydrograph from a catchment in CivilStorm or SewerGEMS is based on a more simplified approach such as the SCS method which only takes the area, permeability factor (like the SCS CN) and Tc into consideration.

FLOOD provides more realistic runoff hydrographs and estimations whereas CivilStorm, SewerGEMS, or StormCAD rely on standard runoff estimation methods such as SCS CN, and IDF Curves for runoff estimation, useful for a more conservative design.

FLOOD can generate advanced water quality and pollutant dispersion modeling studies in water environments.