The Boundary Conditions layer is used to specify boundary conditions for 2D Flow Areas. These boundaries can be considered to be internal or external flow and stage conditions. Internal boundary conditions are used to a attach a Flow Hydrograph inside of the computational domain. External boundary conditions are used for a Flow Hydrograph, Stage Hydrograph, Rating Curve, and Normal Depth. Once a boundary condition line has been created, you will be prompted to enter a unique Name.
When creating a boundary condition line, the line much be entirely outside of the 2D Flow Area to be considered an external boundary; otherwise, it will be treated as an internal boundary. Boundary condition information will then be completed from the Unsteady Flow Data Editor.