Inundation data is required by HEC-FIA for computing consequences. Inundation data provides multiple ways to describe hydraulic characteristics within the study area. The user creates and defines inundation configurations which create a pattern for how the hydraulic characteristics are provided to the compute engine. In HEC-FIA a hydraulic event can be described in many ways, but the minimum requirement is that maximum depth is defined. The parameters that can be defined for an event are as follows:
- Maximum Depth
- Arrival Time (non-evacuation depth)
- Arrival Time (agriculture damage, typically zero depth)
- Duration (for agriculture threshold)
- Maximum Depth Times Velocity
Inundation configurations tell HEC-FIA how input hydraulic data are characterized throughout the floodplain. Seven different types of inundation configurations are covered in this chapter:
- Common Computation Points Only
- Cross Sections Only
- Grids Only
- Grids and Cross Sections
- Holdouts Cross Sections
- Holdout Grids
- Holdout - RAS HDF
Each configuration calculates hydraulic events differently; for more detail on the computational procedures and common issues consult the HEC-FIA Technical Reference Manual.
From an inundation configuration, the user can specify hydraulic events. Events are some combination of the previously described hydraulic event parameters. An event can be defined by an F-Part in a HEC-DSS file, or it could be a specific set of gridded data that describe the hydraulic event. One inundation configuration may have many events. Events are combined with time windows and alternatives to create simulations.