Flood from Cross-Section H

Description

Determine floodplain depth and extent using "cross-section" technique based on user defined water surface elevation field in the cross-section feature class. Input cross-section and water surface elevation field are used to create a water surface tin using cross-sections and WSE as hard breaklines with known elevation. TIN is then converted into raster of the same resolution as DEM and the two surfaces are subtracted. The resulting raster defines water depth raster, and the extent of that raster defined the floodplain polygon. The resulting polygon is not generalized.

The provided result folder is used as a parent directory within which to create the process result folder and store the results of the tool. The short process name is used to name processing results:

• A folder within results directory to contain the process results.
• A geodatabase within the process result folder.
• A floodplain feature class prefixed by “FPPoly”.
• Flood depth raster prefixed by “FD”.
• Unrestricted water surface elevation raster prefixed by “WSE”.
• Unrestricted water surface elevation TIN prefixed by “WSETIN”

For example, for results folder set to “c:\results” and short process name set to “B100”, the tool will generate the following output structure:

• C:\results\B100\Layers\FDB100 – flood depth raster.
• C:\results\B100\Layers\WSEB100 – unrestricted water surface elevation raster.
• C:\results\B100\WSETINB100 – unrestricted water surface elevation TIN.
• C:\results\B100\B100.gdb\Layers\FPPolyB100 – floodplain extent polygon feature class.

Explicit naming of the output layers is not enabled.

If optional hydraulics river feature class is provided, only floodplain elements contiguous to the river will be maintained.

If optional floodplain limit polygon is provided, the floodplain extent polygon and flood depth raster will be limited to that polygon extent (the WSE raster and TIN will NOT be limited).

Usage

Parameters

Parameter Name	Type	Direction	Data Type	Dialog Reference
Input Cross-Section Feature Layer	Required	Input	Feature Layer	Line cross-section feature class that will be used as hard breakline when creating water surface elevation TIN. One of the fields in that feature class needs to contain the water surface elevation to use in floodplain generation.
Input WSE Field	Required	Input	String	Field (numeric type) containing water surface elevation at each cross-section to be used for floodplain delineation.
Input DEM Raster	Required	Input	Raster Layer	DEM raster that will be “flooded”.
Input Results Folder	Required	Input	Folder	Parent folder in which to store results.
Input Short Process Name (up to 10 characters)	Required	Input	String	Short name (up to 10 characters long) that will be used to name the process result folder and resulting layers.
Input Hydraulics River FC	Optional	Input	Feature Layer	Polyline feature class that if provided will be used to limit the extent of flooding to the area that is directly connected to the lines in this feature class (will remove “disconnected” flood polygons). If not provided, disconnected flood polygons will not be removed.
Input Floodplain Limit Polygon FC	Optional	Input	Feature Layer	Polygon feature class that if provided will be used to limit the extent of flooding to the area that is within the polygons in this feature class. This can be used to limit the extent of flooding to individual stream reaches or watersheds. If not provided, there will be no explicit limit to the extent of the derived floodplain (extent of the DEM will define the potential flooding extent).