Check Files 1d mhc

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This GIS layer contains information on the Manholes in the 1D model. Manholes are used to model energy losses at junctions and can occur in the same location as pit channels (which convey water between the ground and the underground drainage network. The manholes can be manually assigned or automatically created and numerous loss methods are available. Refer to the TUFLOW manual for further guidance.

Attributes of mhc_check

Attribute Name Attribute Description
ID The ID of the manhole.
Type The type of manhole, options are:
  • "C" Circular chamber
  • "R" Rectangular chamber
  • "J" Junction with no chamber
Loss_Approach The manhole loss approach. The options are outlined in the Manhole section of the TUFLOW Manual.
Ignore If the manhole has been set to ignore.
Invert_Level The bottom or bed elevation of the manhole.
Flow_Width The flow width of the manhole chamber. Losses are calculated as the flow expands into the manhole chamber and contracts into the outgoing channel.
Flow_Length The length of the manhole chamber in the direction of flow.
ANA Any additional nodal area that has been added at the manhole (value in square metres or square feet).
K_Fixed Fixed component of the calculated manhole loss coefficient. If using the Fixed approach, this is the only coefficient applied.
Km Manhole exit coefficient used by the Engelhund approach.
K_Bend_Max The upper limit of the combination of KƟ and Kdrop in the Engelhund approach.
C_reserved Not used.
N1_reserved Not used.
N2_reserved Not used.
N3_reserved Not used.
i_1d_layer The index to the input layer that has created the manhole. For example an i_1d_layer value of 4 would be the 4th input layer (1d_nwk_M08_pits_001) below.

Read GIS Network == mi\1d_nwk_M04_channels_001.MIF
Read GIS Network == mi\1d_nwk_M05_bridge_001.MIF
Read GIS Network == mi\1d_nwk_M07_trunk_998.MIF
Read GIS Network == mi\1d_nwk_M08_pits_001.MIF

No_Inlet_Culverts The number of incoming culverts based on the digitised direction.
No_Outlet_Culverts The number of outgoing culverts based on the digitised direction.
Highest_Soffit The elevation of the highest soffit (obvert) for the connected channels.
Surface_Area The surface area of the manhole.


For MapInfo users the style of the point object is dependent on the manhole type and dimensions. For example a "C" (circular) type manhole is shown as a circle object with the size proportional to the flow width.