Manholes are junctions placed at the intersection of two or more links. Three types of manholes exist in a sewer collection system.
- Normal: Where the physical location of a manhole exists in the collection system or a physical break is needed for a change in pipe attributes (e.g. diameter, material).
- Chamber: A quasi-node placed to represent a break between a pump and a force main. No loads can be defined for a chamber.
- Outlet: The facility where sewage flows exit the collection system. These nodes define the discharge end or the most downstream element of a sewer network. The exit condition can be grouped into four cases as shown below.
§ Nonsubmerged, free fall
§ Nonsubmerged, continuous
§ Nonsubmerged, hydraulic jump, Submerged
Manholes must also have their elevation above datum (e.g., sea level) specified in order for HGL profiles to be generated. Click here to view the fields required for a manhole.
How do I…
- Create a manhole?
- Edit a manhole?
- Edit a group of manholes?
- Delete a manhole?
- Recall a deleted manhole?
To create a manhole, click on the create node icon or from the Create menu, click Add/Insert Manhole.
Once the command is initiated, a crosshair cursor will appear. Select the location of the new node by left mousing clicking anywhere on the map display.
With the manhole placed, a dialog box will appear requesting the ID for the manhole, a description and the type of manhole being placed (Normal, Chamber, or Outlet). Once an ID, description and type are specified, press OK to end the command.
(Note: You can also use the Digitize Network command from the Create menu to create a pipe and node network at the same time. Once digitized, the user is able to add relevant modeling data in the Attribute Browser dialog box.)
Graphic Edit – To edit the manhole graphically, use the Move Node icon to select the node. Once the node is selected, left mouse click on top of the node and hold the button and drag the mouse at the same time. A red rubber band will appear showing the user where the node will be located. Once the node is moved to its new location, release the mouse button. The node is now relocated. (Note: If the user has not enabled “Auto Length Calculation” under the Tools -> Preferences menu, all pipes connected to that node will not have their lengths automatically changed.)
Data Edit – To edit the data related to a node, first select the node using the Select icon. Once selected, the user is able to edit the database data related to the node under the Node tab of the Attribute Browser dialog box.
Group edits can be made by either creating a domain first and then selecting the Edit Domain Attributes icon, or the user can use the Edit Selection Attributes icon. Both icons are found on the Edit Network toolbar or can also be found under the Edit Menu.
Once the Edit Selection Attributes command is initialized, the user makes a selection and presses the <Enter> key. At this point, the Edit Attribute dialog box is displayed allowing the user to edit any field for any of the 4 data elements that may have been selected.
To delete a manhole, from the Edit menu, select Delete Node or select the Delete Node icon. H2OMAP Sewer will prompt the user to confirm deletion. (Note: All links attached to the node being deleted will also be deleted.) The node and associated links are deleted graphically but can still be recalled from the database using the recall command. However, if Auto Database Packing is enabled (Tools -> Preferences), then any element deleted is permanently deleted from the database and cannot be recalled.
To recall a deleted node, go to Utilities menu, point to Recall, then select Node. In order to perform the recall, the user must know the ID of the node that was deleted. If the ID is unknown, select the Show Deleted Nodes command from the Recall menu to see a list of ID’s that have been deleted.