Elevation-Derived Hydrography READ Rules: Connector: Terrain Breach
A Connector: Terrain Breach is used to breach terrain (or elevation) features that block the flow in a drainage network, such as a small rise in elevation, landslides, moraines, glacial till, or naturally formed berms.
Use
A terrain breach connector is used to breach flow blockages on the elevation surface; with no known built feature connecting upstream and downstream flow (figure 11 and figure 12). In contrast, the underground conduit (FCode 42002) is used to represent an underground flowpath in known karst, permafrost, and thermokarst terrain; the culvert connector (FCode 33401) is used to connect upstream and downstream flow through a transportation feature; and connector (FCode 33400) is used to connect underground flow from upstream to downstream through built environments such as a dam.
Attribute/Attribute Value
Each feature requires domain codes to be entered into the attribute table for the feature class (Elevation-Derived Hydrography Feature type description, associated geometry, and use classification table in the Elevation-Derived Hydrography Data Acquisition Specifications 2023 revision A2). See “Field Definitions and Domain Values for Attributes” section for more information on Elevation-Derived Hydrography code definitions.
Delineation
The limit of Terrain Breech Connector is the virtual line connecting two nonadjacent network segments, from the lowest point on one side of the obstruction to a point at or below the beginning point on the other side of the obstruction.
Representation Rules
When delineating a feature, it must be created with the appropriate geometry, either point, line, or polygon, which is determined by the size of the feature or the length along different axes of the feature (table 6).
Special conditions: none.
Table 6. Connector: Terrain Breach Representation Rules.
| Kind of feature object | Area | Shortest Axis | Longest Axis |
| 0-dimensional (point) | -- | -- | -- |
| 1-dimensional (line) | -- | greater than 0 | -- |
| 2-dimensional (polygon) | -- | -- | -- |
Data Extraction
Capture Conditions
If Terrain Breach Connector is required to maintain connectivity through a rise in elevation between two network feature objects,
then capture.
If Terrain Breach Connector with a rise in elevation extends in length for three pixels or more than the source resolution (3 meters for lidar, 15 meters for IfSAR) within the terrain,
then capture.
Attribute Information
FClass 1—Hydrography feature defined within the collection criteria of the elevation-derived hydrography specifications.
FCode 33405—Terrain Breach Connector (Used to breach terrain (or elevation) features that lock the flow in a drainage network, such as a small rise in elevation, landslides, moraines, glacial till, or naturally formed berms).
EClass 3— Linear features below ground level—Examples include connectors through dams, culvert connectors, and terrain breach connectors. Used for hydro-enforcement.
Source Interpretation Guidelines
All
The following list of conditions indicates when and why the capture of Terrain Breach Connector is required:
- When Terrain Breach Connecter is part of a network that is represented as connected.
- When there is a gap caused by a rise in elevation greater than or equal to 2 meters in Alaska and greater than or equal to 1 meter in CONUS.
Special Conditions: none.
