WMS:Pipe and Node Parameters

GSSHA Pipe and Node Parameters dialog.

The GSSHA Pipe and Node Parameters dialog is accessed by clicking in the Edit Pipes and Nodes column in the GSSHA feature arcs Properties dialog. This is only accessible when a GSSHA storm drain coverage is active. This dialog is used for building and editing the pipes and nodes associated with superlinks (arcs) and superjunctions (nodes) when running a GSSHA storm and tile drain simulation.

When running a GSSHA storm and tile drain simulation, it is recommended to add more than one pipe (two nodes) between superjunctions. In WMS, superlinks are represented as arcs and superjunctions are represented by the two nodes at the end of each arc. Each link may contain one or more pipes and two or more nodes. Many of the attributes between superjunctions and nodes between superjunctions overlap.

If a specific parameter needs to be copied to all or some other pipes or nodes below the one currently selected, click and hold the small square at the bottom right corner of the selection and drag down until the value is copied to the desired cells. Double-clicking on this square will copy the selected value to all entries below it.

If wanting all the attributes for the displayed arcs to be the same, set the value in the top cell of the dialog. Double-click on the small square in the lower left corner of the selected field (below) and the attribute will be copied to all the other pipes or nodes that are displayed.

The following buttons are found at the bottom of this dialog:

• Help – Opens this article in a web browser.
• OK – Saves all changes and closes the GSSHA Pipe and Node Parameters dialog.
• Cancel – Discards all changes and closes the GSSHA Pipe and Node Parameters dialog.

The superlink number is displayed at the top of each set of superlink attributes.

Pipes

In the Pipes section, the following options are available at the top:

• Initialize Pipes from Arc Geometry – Creates a pipe for each arc segment on the selected arc and creates a node for each node or vertex on the arc. Attributes associated with the superlink (arc) and superjunctions (nodes) are transferred to the generated pipes and nodes, but these transferred data values can be edited. Node ground surface elevations are extracted from the 2D grid elevations at the location of each node or vertex on the selected arc. These pipes and nodes are output to the GSSHA Storm Pipe Network (SPN) file when the GSSHA project run. It is important to define pipe and node parameters for all the pipe arcs in the storm or tile drain network.
• Delete Pipes – Delete the selected pipe(s) and nodes from the arc. Re-initialize the pipes from the arc geometry after making any changes that need to be made or WMS may not output the correct pipe and node attributes for the selected arc.
• Show – Affects both the Pipes and Nodes spreadsheets. A drop-down with the following options:
  • "Current arc" – Shows only pipes associated with the current arc described on the row in the GSSHA feature arcs Properties dialog where the button was clicked when opening this dialog.
  • "Selected arcs" – Shows only pipes associated with the arcs currently selected in the Main Graphics Window.
  • "All arcs" – Shows pipes associated with all arcs on the GSSHA storm drain coverage.

The spreadsheet has the following columns:

• Pipe Type – A drop-down with the following options:
  • "Circular"
  • "Rectangular"
• Diameter/Height – A decimal value in meters for diameter (circular pipes) or height (rectangular pipes).
• Width – A decimal value in meters.
• Slope – A decimal ratio of horizontal rise to one unit of vertical rise (m/m).
• Manning's n – A decimal Manning's n roughness value.
• Length – A decimal distance in meters.
• Conductance – A decimal distance value describing the average distance water travels through the pipe walls in centimeters per hour.
• Drain Spacing – A decimal distance in meters for regularly-spaced openings that allow water to infiltrate into the groundwater.

Adverse Slope Detection

If a segment on an arc has an adverse slope, and the option to display adverse slopes is turned on, WMS displays in red the arc with the adverse slope. If any of the stream or pipe arcs in a GSSHA model have adverse slopes, an warning will display in the GSSHA Model Check dialog indicating which pipe arc IDs have adverse slopes.

Nodes

The distribution of vertices (nodes) along an arc (superlink) in the GSSHA storm drain coverage is important in the storm/tile drain model used by GSSHA. Space nodes closely near junctions and farther apart toward the center of the superlink. WMS has an option in the Redistribute Vertices dialog for feature arcs that allows for defining a second bias. Each of the bias values defines the ratio of spacing between vertices at the center of the arc and at the middle of the arc. Use the same bias value along with a specified vertex spacing or a number of vertex segments to define vertices close together at the ends and far apart at the center of the superlink.

WMS 10.0 and later versions automatically update the pipes and nodes for a superlink when a vertex is added or deleted along an arc. When redistributing vertices on an arc, WMS updates the pipes and nodes on that arc. The attributes for the new pipes and nodes are assigned based on the attributes assigned to the arc and the upstream superjunction point before adding vertices to the arc.

WMS 10.0 and later versions also have an option in the WMS Display Options that allows displaying a special symbol for any nodes or superjunctions in the GSSHA Storm Drain coverage that have more than zero inlets.

The Nodes spreadsheet has the following columns:

• Ground Surface Elevation – A decimal elevation value in meters.
• Invert Elevation – A decimal elevation value in meters.
• Manhole Area – A decimal area value in square meters.
• Inlet Type – A drop-down with the following options:
  • "0 grate inlets (no flow capture)"
  • "1 grate inlets"
  • "2 grate inlets"
  • "3 grate inlets"
  • "4 grate inlets"
  • "5 grate inlets"
  • "6 grate inlets"
  • "7 grate inlets"
  • "8 grate inlets"
  • "9 grate inlets (all flow captured)"
  • "Node connects to junction"
• Weir Side Length – A decimal length value in meters.
• Orifice Diameter – A decimal diameter value in meters.
• Hydrograph output – Turn on to enable output to a hydrograph. GSSHA hydrographs are displayed at node/vertex locations instead of at grid cell centers since WMS reads the hydrographs based on link/node, pipe/node, or superjunction numbers.