Defining Riser Outflow Pipe

The Riser Outflow Pipe panel of the Storage Area Data dialog box allows the user to define general parameters for the pipe that directly discharges flow captured by the vertical riser structure. This article describes how to interact with the Riser Outflow Pipe panel. Refer to this article in our knowledge base to learn more about the Storage Area Data dialog box.

Follow the steps below to define the specifications for the riser outflow pipe:

1. In the Storage Area Data dialog box, select Riser Outflow Pipe from the Storage Area Specifications dropdown combo box.
   
2. The corresponding panel with options for defining the riser outflow pipe will be displayed.
   

Pipe Definition

This section allows the user to define the general parameters for the selected pipe.

The following options are provided in this section:

• Pipe shape
  This dropdown combo box allows the user to select the type of pipe shape. The following pipe shapes are available:

• 1. Arch
  2. Box
  3. Circular (default)
  4. Ellipse
  5. Pipe Arch
     

• Backflow flap gate
  This checkbox option specifies whether a flap gate will be enabled to prevent backflow (or flow reversal) for the pipe. By default, this checkbox option is unchecked.

• Pipe type
  This dropdown combo box lists the available pipe types that are supported. Note that the options in the dropdown combo box will change based on the selected pipe shape.

• Pipe entrance
  This dropdown combo box lists the available pipe entrance types that are supported. Note that the options in the dropdown combo box will change based on the selected pipe shape.

• Number barrels
  This spin-control entry defines the number of identical pipe barrels that are defined. By default, the software uses a value of 1. However, the user can enter a value ranging from 1 to 10.

Pipe Dimensions

This section allows the user to define the dimensions and other parameters of the pipe.

The following options are provided in this section:

• Diameter or height
  This entry field defines the diameter of a circular pipe or the height of a box pipe shape.

• Width or span
  This entry field defines the width (or span) of a box pipe shape. Note that this entry field is enabled only when Box is selected as the pipe shape under the Pipe Definition section. Otherwise, this entry field is disabled (i.e. grayed out).

• Pipe length
  This entry field defines the length of the pipe being modeled. The user can click the [Pick] button to measure the pipe length from the Map View.

• Inlet invert elevation
  This entry field defines the pipe invert elevations on the upstream (inlet) end. The user can click the […] button to select the pipe inlet invert elevation from the Map View. Clicking the [Down] arrow button causes the pipe invert elevation to be set equal to the storage area invert elevation.

• Outlet invert elevation
  This entry field defines the pipe invert elevations at the downstream (outlet) end. The user can click the […] button to select the pipe outlet invert elevation from the Map View. Clicking the [Down] arrow button causes the pipe invert elevation to be set equal to the storage area invert elevation.

• Pipe slope (H:V)
  This entry field displays the slope of the pipe. In addition, this field can be used to set the slope of the pipe. The user can click on the edit option (i.e., the pencil icon) adjacent to the Pipe slope (H:V) field to change the read-only field into an editable field. The user can then enter the pipe slope and click on the [Accept changes] button. The software will then adjust the unlocked pipe end invert elevation to meet the updated slope value.
  
  Note: To set the slope of the pipe, the user should first select the end of the pipe invert elevation that is to be locked.

   

  The following options are provided in the dropdown combo box adjacent to the Pipe slope (H:V) entry field:

• 1. Lock Downstream Invert
  2. Lock Upstream Invert

Pipe Coefficients

This section allows the user to define Manning’s roughness, entrance loss and exit loss coefficients for the selected pipe.

The following options are provided in this section:

• Manning’s roughness
  This entry field defines the roughness of the pipe. Clicking the […] button displays the Manning’s Roughness lookup dialog box, which allows the user to choose Manning’s roughness coefficient to be assigned to a pipe.
  
  

• Entrance loss coefficient
  This entry field defines the head loss coefficient associated with energy losses at the inlet of the pipe as the flow enters the pipe from a node (i.e., manhole, junction box, routing junction, catch basin, or storage area). Clicking the […] button displays the Pipe Entrance Loss Coefficients lookup dialog box, which allows the user to choose the entrance loss coefficient to be assigned to a pipe.
  
  

• Exit loss coefficient
  This entry field defines the head loss coefficient associated with energy losses at the outlet of the pipe as the flow leaves the pipe and enters a node (i.e., manhole, junction box, routing junction, catch basin, or storage area). Clicking the […] button displays the Pipe Exit Loss Coefficients lookup dialog box, which allows the user to choose the exit loss coefficient to be assigned to a pipe.