Manholes are physical structures that connect pipes. They may be circular or rectangular in shape.
Junction Type - Select either Simple Junction or Manhole from the drop-down list.
Easting - The easting coordinate at the centre of the icon on Plan.
Northing - The northing coordinate at the centre of the icon on Plan.
|The Cover Level, Depth and Invert Level are linked so that whichever parameter is highlighted with the radio button will be calculated from the other two variables.|
Cover Level - The ground level (above datum) and the level where flooding is reported. An overflow or spillway crest level may be specified at a lower level as part of the outlet control details. If a Surface Data is present the Cover Level will automatically be picked up from the centre of the icon. Above the Cover Level, water will be stored above the ground and then allowed to drain back into the network. The default ponding area used for the flooded volume is 1000 m².
Depth - The depth of the manhole, i.e. the Cover Level minus the Invert Level.
Invert Level - Represents the level (above datum) of the base of the manhole.
Chamber Shape - Select the chamber shape as Circular or Rectangular to enable the dimensions to be set.
Diameter - The diameter is shown if Circular is selected as the Chamber Shape.
Length - The length is shown if Rectangular is selected as the Chamber Shape.
Width - The width is shown if Rectangular is selected as the Chamber Shape.
Where a manhole is an outfall with no outlets, the analysis will ignore the chamber dimensions as it is seen as free discharging (except where there is an surcharged level).
When set to rectangular, the manhole will orient itself towards the biggest outgoing connection (or the last placed connection, if there are multiple connections of the same size as the biggest).
Is Access Required - This checkbox determines if the manhole requires access and therefore if an offset needs to be calculated. Checking this box enables the pipe intersection fields.
Intersection Easting - The easting coordinate of where the incoming and outgoing connections meet inside the junction.
Intersection Northing - The northing coordinate of where the incoming and outgoing connections meet inside the junction.
The Is Access Required box is only visible for a Circular Manhole. This is due to an offset that is only required for Circular Manholes.
Manhole Locked - This checkbox determines if the manhole is locked, which prevents it from being affected from the manhole sizing calculations.
Refer to the Inlets and Outlets pages for more details on these tabs.