Defining Storage Area Spillways

The Storage Area Spillways panel of the Storage Area Data dialog box allows the user to define a spillway that directly discharges from the storage area to the downstream element of the project without going through a vertical riser structure. This article describes how to interact with the Storage Area Spillways 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 specifications for storage area spillways:

1. In the Storage Area Data dialog box, select Storage Area Spillways from the Storage Area Specifications dropdown combo box.
   
2. The corresponding panel with the options for defining storage area spillways will be displayed.
   

Spillway Definitions

This section provides a data grid that allows the user to define the type and flow direction of the spillway.

The following column entries are provided in this data grid:

• Spillway Type
  This dropdown combo box allows the user to select the type of spillway to be used. The following entries are provided in the dropdown combo box:
  1. None
  2. Roadway
  3. Standard – Rectangular
  4. Standard – Trapezoidal
  5. Standard – V-Notch
     
• Flow Direction
  This dropdown combo box allows the user to select the flow of the spillway being routed. The following entries are provided in this dropdown combo box:
  1. Auxiliary
  2. Main

Standard Spillway Specifications

This section allows the user to define specifications for a standard spillway.

Note that this section is disabled (i.e., grayed out) when Roadway is selected as the spillway type in the Spillway Definitions section.

The following parameters are provided in this section:

• Spillway crest elevation
  This entry field defines the spillway crest elevation. Clicking the […] button allows the user to measure the elevation of the spillway crest from the Map View.
• Spillway length
  This entry field defines the bottom width of a rectangular and trapezoidal spillway. Clicking the [Pick] button allows the user to measure the length of the spillway from the Map View. Note that this entry field is disabled (i.e., grayed out) when Standard – V-Notch is selected as the spillway type in the Spillway Definitions section.
• Spillway side slope (H:V)
  This entry field defines the side slope of the sides of a trapezoidal and V-notch spillway. Note that this entry field is disabled (i.e., grayed out) when Standard – Rectangular is selected as the spillway type in the Spillway Definitions section.
• Spillway discharge coefficient
  This entry field defines the weir discharge coefficient for the spillway structure. Clicking the […] button displays the Weir Coefficients lookup dialog box, allowing the user to select the weir discharge coefficient that can be assigned.
  

Roadway Spillway Specifications

This section allows the user to define input data for the roadway to act as a spillway.

Note that this section is enabled only when Roadway is selected as the spillway type in the Spillway Definitions section. Otherwise, this section is disabled (i.e., grayed out).

The following parameters are provided in this section:

• Roadway centerline elevation
  This entry field defines the roadway crest elevation. Clicking the […] button allows the user to measure the elevation of the roadway centerline from the Map View.
• Roadway length
  This entry field defines the length of the roadway that will act as a spillway. Clicking the [Pick] button allows the user to measure the roadway length from the Map View.
• Roadway width (in flow direction)
  This entry field defines the width of the roadway (in the direction of flow) that will act as a spillway. Clicking the [Pick] button allows the user to measure the roadway width from the Map View.
• Roadway discharge coefficient
  This entry field defines the weir discharge coefficient for the roadway structure that will act as a spillway.
• Roadway surface type
  This dropdown combo box allows the user to select the type of roadway surface that will act as a spillway. The following roadway surface types are provided:
  1. Gravel Surface
  2. Paved Surface