FM Tutorial M01 QGIS GPKG 1D2D Links: Difference between revisions
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Created page with "<ol> =Introduction= In this section we will set up the Flood Modeller-TUFLOW linkage to apply a water level boundary to the 2D cells along the 1D/2D interface. In the 2D boun..." |
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=Introduction=
In this section we will set up the Flood Modeller-TUFLOW linkage to apply a water level boundary to the 2D cells along the 1D/2D interface. In the 2D boundary condition (2d_bc) GIS layer, we define the location at which this link occurs. The 2D water level applied at the 2D boundary cells is calculated in the 1D Flood Modeller
Depending on the water level in the surrounding 2D cells, flow can either enter or leave the HX cells. The volume of water entering or leaving the 2D boundary is added or subtracted from the 1D Flood Modeller model to preserve volume. We must connect the HX lines to the 1D Flood Modeller model. This is done using CN type lines in the 2d_bc layer, where a CN line is connected to the HX line, the water level from the 1D Flood Modeller nodes is transferred to the HX line. In between 1D nodes, a linear interpolation of water level is applied. This is shown in the figure below.
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<br>Often HX lines are located along the top of a levee (natural or artificial) or flood defence running along the river bank. When carving a 1D channel through a 2D domain, the HX line must be either on the top of the levee or on the inside of the levee (closest to the channel). If the HX line is located on the other side of the levee away from the channel, the effect of the levee on water flow is <u>'''not'''</u> modelled. In the sections above, it can be seen that the boundary cell is along the levee and the interaction between the channel and the floodplain (1D and 2D) occurs at the correct elevation. <br>
<br>Where there are junctions within the Flood Modeller 1D model (i.e. at structures), both the nodes immediately upstream and downstream must be connected to TUFLOW. The HX lines must be broken between the junctions as this is a requirement of a linked Flood Modeller – TUFLOW model<br>.
<br>The generation of the 1D-2D links for Flood Modeller – TUFLOW models can be partially automated through the use of the [https://help.floodmodeller.com/v1/docs/how-to-use-the-tuflow-link-lines-generator-tool TUFLOW Link Line] tool in Flood Modeller
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