Hydraulic structures (Water Overlay)

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The water system can be enhanced with a number of hydraulic structures. These are constructions which transport water to, from, and between specified cells, according to their flow model and given parameters. The behavior of these constructions can be adjusted by adjusting the related attributes.

In general, for ease of use, hydraulic structures are by default imported as underground constructions.

Icon Name Category Type Identification key
Waterwizard icon inlet.png Inlet Hydraulic structure Point INLET_Q
Waterwizard icon pump q.png Pump Hydraulic structure Line PUMP_Q
Waterwizard icon culvert.png Culvert Hydraulic structure Line CULVERT_DIAMETER
Waterwizard icon sewer overflow.png Sewer overflow Hydraulic structure Point SEWER_OVERFLOW
Waterwizard icon weir.png Weir Hydraulic structure Line WEIR_HEIGHT

In order to get more familiar with the different hydraulic structures in the Water Overlay check out Quadrant 3 of the Water Module Testbed. This Testbed is available to you as a project in the Tygron Platform.


Hydraulic structures can be either line-based or point-based:

  • Line-based constructions
    Line-based constructions form a direct connection between two exact cells, allowing water to flow from one point to another. The flow is dictated by the construction's formula. The endpoints of a line-based construction, the exact cells which are connected by the construction, are computed based on the orientation and size of their polygon. Essentially, the furthest ends of the polygon are used as end-points. Because the cells of either endpoint are considered adjacent, any calculated flow through line-based hydraulic structures is instantaneous.
  • Point-based constructions
    Point-based constructions add or remove water in one or more computational layers, based on their formula's. The center-point of a point-based construction, the exact cell where the effect takes place, is the geometric center of the construction's polygon.

Note that the more complex the polygon is, the more difficult it is for the Tygron Platform to resolve it to a simple line or center point.


Constructions can be identified as a hydraulic structure when this construction has the identification attribute. This is the first attribute in the described table of attributes for each hydraulic structure. They are also listed in the table above.

The identification attribute (and all other attributes used by hydraulic structures) can be configured as a key of the Water Overlay. Keys indicate which attribute of constructions or features is used to represent specific geographical input parameters for the calculation. This can be of use when setting up a project or template which makes use of user-provided geodata.

Total flow

When the calculation of the water overlay completes, the total amount of water that has flowed through a specific construction is stored in an attribute in that construction. By default, this attribute is OBJECT_FLOW_OUTPUT, and the flow is expressed in m3. Since multiple water overlays can exist in the project simultaneously, the attribute name is appended with an underscore and the overlay ID such that each overlay (as they are added to the project) can write to a unique attribute.


  • Only one hydraulic structure can be assigned to a particular grid cell.
  • The Base type result overlay visualizes which type of hydraulic structures are placed where.
  • If a single construction has attributes related to multiple hydraulic structures, only one is selected. The selection order is: Weir, Sewer overflow, Inlet, Pump, Culvert.