SMS:SRH-2D Pressure Flow Bridge Workflow

To build a pressure flow bridge for an SRH-2D model, use the following steps:

1. Create two bridge pressure flow boundary condition arcs.

Create two feature arcs representing the upstream (beginning) and downstream (ending) locations of the pressure zone. 1. Create feature arcs, nodes and vertices. In the Map module, create feature objects in the active coverage. Use the Create Feature Arc tool to create arcs in the map coverage. Begin creating a new arc by clicking in the Graphics Window at either arc end. If clicking on an existing feature node, vertex or arc, the new arc will snap to that object. Double-click or press the Enter key to terminate the arc. Use the Create Feature Node tool to create additional nodes alone or to split arcs. 2. Modify arcs. Feature arcs often need to be edited after initial creation. 1. Create additional vertices on arcs. Use the Create Feature Vertex tool to add vertices along arcs. 2. Refine the arc shape. Use the Select Feature Vertex tool and the Select Feature Node tool to move/edit existing arcs and refine the shape by dragging the nodes/vertices. Use the Select Feature Arc tool to move entire arcs . 3. Split arcs. An existing arc can be split by: 1. Converting a vertex to a node. Use the Select Feature Vertex tool and right-click on a vertex along an arc. Select the Convert to Node command to split the arc into two arcs. 2. Add a node the arc. Use the Create Feature Node tool to add a node on an arc in order to split it into two arcs. 3. Add a new connecting arc. Use the Create Feature Arc tool to start or end a new arc on an existing arc to split the existing arc into two arcs. 4. Use the Split Arcs Tool. Right-click on an arc using the Select Feature Arc tool and select the Split Arc(s)... command. Use the Split Arcs Tool to divide arcs. 5. Split overlapping arcs using the Clean Options dialog. Select overlapping arcs using the Select Feature Arc tool. Use the Feature Objects | Clean command to bring up the Clean Options dialog. Select the Intersect selected arcs option (for selected arcs) or Intersect arcs option (for all overlapping arcs) to split the arcs. 4. Merge arcs. Two arcs that share an end node can be merged together. Select the shared node using the Select Feature Node tool. Right-click on the node and select the Convert to Vertex command to merge the arcs. If desired, the Select Feature Vertex tool can be used to select and delete the new vertex. 5. Smooth arcs. The variability or roughness of an arc can be reduced. Right-click on an arc using the Select Feature Arc tool and select the Smooth Arc(s)... command. Use the Smooth Arcs Tool to reduce the variability of the arc. 6. Prune arcs. Concave sections of the arc can be removed. Right-click on an arc using the Select Feature Arc tool and select the Prune Arc(s)... command. Use the Prune Arcs dialog to remove concave sections. 7. Extend/trim arcs. Extend or shorten an arc to match an existing arc's length. Using the Select Feature Arc tool, select two intersecting arcs. Right-click on an arc using the Select Feature Arc tool and select the Extend/Trim Arc... command. Use the Trim/Extend Arc dialog to select the target arc and source arc.

2. Assign bridge pressure flow boundary conditions.
Using the Select Feature Arc tool, select both bridge pressure flow arcs. Right-click and select the Assign Linear BC... command. In the SRH-2D Linear BC dialog, assign the bridge pressure flow boundary conditions specifying the upstream and downstream arcs and the ceiling elevation and Manning roughness coefficient.