Identify Breach Areas
Description
Identify potential areas that need to be breached. Tool identifies depression areas in the input DEM based on the difference between filled and original DEM. It also calculates their basic properties - surface area, depth, and volume. These properties can then be used to limit the selection of the final areas based on user provided selection limits. Internally, the tool will automatically eliminate all areas whose fill depth is less than 0.05 vertical units to remove "noise" from further analysis.
The user provided limits are applied in "AND" operation, so only those areas meeting all provided limits will be selected and provided as outputs. Default limit values are 0 for all three parameters. If all limit values are 0, then no selection will be performed, and all filled areas will be processed.
Tool generates the raster and vector representation of the filled area and the point at the location of the maximum filled depth for each area. The point features also include area attributes as well as POINT_X and POINT_Y (x and y coordinates of the point) and ELEVATION (point elevation).
The intent of the tool is to generate potential areas/points that indicate large filled areas that might need to be breached via man-made structures. Not all identified locations might need such structures, so other selection criteria can be used for further selection (such as proximity to roads, existing flow paths, etc.).
Usage
Parameters
| Parameter Name | Type | Direction | Data Type | Dialog Reference |
|---|---|---|---|---|
| Input DEM Raster | Required | Input | Raster Layer | Input elevation raster. |
| Breach Area Depth Limit | Required | Input | Double | Depth threshold (in map units) applied to limit which areas are considered needing breaching. Areas whose maximum depth ("RANGE" attribute) is less than the threshold will NOT be considered in the final output. Default is 0, meaning that all areas will be considered. |
| Breach Area Area Limit | Required | Input | Double | Area threshold (in map units) applied to limit which areas are considered needing breaching. Areas whose area ("AREA" attribute) is less than the threshold will NOT be considered in the final output. Default is 0, meaning that all areas will be considered. |
| Breach Area Volume Limit | Required | Input | Double | Volume threshold (in map units) applied to limit which areas are considered needing breaching. Areas whose volume ("VOLUME" attribute) is less than the threshold will NOT be considered in the final output. Default is 0, meaning that all areas will be considered. |
| Output Breach Area Raster | Required | Output | Raster Layer | Output raster indicating potential breach areas. The output is of integer type. Each distinct area has unique value. |
| Output Breach Area Polygon | Required | Output | Feature Layer | Output potential breach area polygon feature class. Each polygon identifies distinct breach area and matches the extents in its aster representation. Attribute "gridcode" matches the VALUE of the breach area raster. |
| Output Breach Area Point | Required | Output | Feature Layer | Output potential breach area point feature class. Point within each breach area is placed at the "deepest" filled location (minimum elevation) within the breach area. Besides properties of the breach area (AREA, RANGE, and VOLUME attributes), point will also have attributes: |