Storage Areas are lake-like regions where water can be channeled in or out. In CivilGEO’s software, the user can use the Automated Draw Storage Areas command to define the boundary of a storage area. The software defines the storage area boundary by creating a planar surface at the defined water surface elevation and then intersects it with the defined terrain surface. The resultant clipped polygon represents the storage area (or reservoir).
Follow the steps below to use the Automated Draw Storage Areas command.
- From the Input ribbon menu, click the Storage Areas dropdown menu and select the Automated Draw Storage Areas command.
- The Automated Draw Storage Areas dialog box will be displayed.
The following sections describe the Automated Draw Storage Areas command and how to interact with the above dialog box.
Storage Area Specifications
The Storage Area Specifications section is used to define the storage area ID. By default, the storage area ID is automatically suggested in the Storage area ID entry using a predefined format. However, the user can enter a different ID if needed.
General Specifications
The General Specifications section is used to define the general specifications for drawing the storage area.
The following options are available:
- Terrain surface
The dropdown combo box lists the terrain surfaces associated with the project, which are used to define the storage area boundary. By default, the current scenario’s terrain surface is selected. If there is no terrain surface defined for the selected scenario, then this entry is undefined. Note that the dropdown combo box does not list the hybrid terrain surfaces (i.e., composite of different terrain surfaces).
- Thin boundary polyline (removes redundant vertices)
This checkbox option removes redundant vertices that do not contribute to the shape of the generated storage area boundary. By default, this checkbox option is checked.
- Smooth boundary polyline
This checkbox option controls whether extra vertices are added along the storage area boundary to improve their appearance. By default, this checkbox option is checked.
Defining Storage Area Boundary Limits
The Define Storage Area Boundary Limits section is used to define the maximum limits for generating the storage area boundary.
The following options are available:
- Current screen limits
When this option is selected, the software will use the current extents of the Map View as the boundary limit for generating the storage area boundary.
- User-defined limits
When this option is selected, the user can click the [Pick] button to draw a rectangular region to define the storage area boundary limits on the Map View. Clicking the [Pick] button temporarily hides the dialog box. The user can then draw a rectangular region to define the limits on the Map View. After releasing the mouse, the user will be returned to the dialog box. The User-defined limits read-only field will be changed from Undefined to defined.
- Terrain surface limits
When this option is selected, the terrain surface area used to generate the storage area boundary will have the same extent as the elevation grid.
- Model extents
When this option is selected, the software will create a rectangular bounding region to the extents of the defined model, along with an additional buffer boundary.
Computing Storage Area Boundary
The Compute Storage Area Boundary section is used to define where the software should create a storage area boundary. The software requires the user to select a point within or on the boundary of the storage area to define the parameters for computing the storage area boundary. Note that if there is no terrain surface defined for the selected scenario, then this section is disabled (i.e., grayed out).
The following options are available:
- Select point in storage area
This option allows the user to select a point within the storage area or on its boundary. Clicking the […] pick button will cause the Automated Draw Storage Areas dialog box to temporarily disappear. A prompt will be displayed on the status bar instructing the user to select a point on the Map View. After selecting a point, the user is immediately returned to the dialog box, and the read-only field will be changed from Undefined to Defined.
- Storage area crest elevation
This entry field allows the user to define an elevation at which the software will determine the storage area boundary. Alternatively, the user can click the […] pick button to select the crest elevation from the Map View.
- Compute storage area boundary
Clicking the [Compute] button causes the software to compute the storage area boundary. Note that this button is disabled until the user defines all the required options in the dialog box needed for computing the storage area boundary.
Computing Storage Area Volume
The Compute Storage Area Volume section is used to define how the software should compute the storage area volume curve. Note that this section is disabled (i.e. grayed out) until the user has computed a storage area boundary.
The following options are available:
- Storage area maximum elevation
This entry field allows the user to define the maximum elevation to be used in computing the storage area volume curve for the selected storage area. Note that the software automatically computes this entry once the storage area boundary has been computed. However, the user can enter a different value if needed. Alternatively, the user can click the […] pick button to select the storage area’s maximum elevation from the Map View.
- Storage area minimum elevation
This entry field allows the user to define the minimum elevation to be used in computing the storage area volume curve for the selected storage area. Note that the software automatically computes this entry once the storage area boundary has been computed. However, the user can enter a different value if needed. Alternatively, the user can click the […] pick button to select the storage area’s minimum elevation from the Map View.
- Storage area depth
This read-only field represents the difference between the Storage area maximum elevation and the Storage area minimum elevation entries.
- Storage area volume depth increment
This dropdown combo box allows the user to select the storage area volume depth increments. The dropdown combo box lists the following storage area volume depth increments:
- 1
- 25
- 50
- 1 (default)
- 2
- 5
- 5
- 10
- 20
- Compute storage area volume
Clicking the [Compute] button causes the software to compute the storage area volume. The software will then update the Elevation Area Volume Plot with the extracted storage area volume curve data from the selected terrain surface, as shown below.
The software will also update the corresponding Elevation Area Volume Data Table with the extracted storage area volume curve data from the selected terrain surface, as shown below.
Assigning Storage Area
When all the options have been defined in the Automated Draw Storage Areas dialog box, click the [Assign] button. The software will then define the storage area on the Map View.