Once the FE mesh has been finalised, the necessary model data must be assigned. This includes, for example, fixed potential heads as boundary conditions of the first kind (POTE), watercourse water level (stage) and leakage coefficients at streams (VORF and LERA), groundwater recharge rates (FLAE), hydraulic conductivity values (KWER), well abstractions (KNOT) or areas with uniform potential heads (GLEI).

It should be noted that data that is required throughout the modelled area, such as hydraulic conductivity values, subsurfaces or terrain elevations, must be assigned to all or by interpolation so that all elements or nodes are fully occupied.

Data that is only required at specific points or lines, such as leakage coefficients, well abstractions or fixed potential heads at the boundary of the model, can be assigned directly.

The existing structure data file schritt2_netz.str contains the data types POTE, VORF, KNOT and GLEI associated with the structure. To assign the data as attributes in the model, perform the following:

Via the Structure Assign List... or Attributes Assign From structure... List... menu items, the following dialogue appears:

Assigning structural data

All structures can be selected using the left mouse button while pressing the SHIFT key and clicking on the top and bottom structures, the dialogue is then confirmed with the "OK" button. Another dialogue window will appear in which the precision parameters of the assignment can be defined. (Note: Data type DATA is always ignored when assigning.)

Assignment parameters

If no further modifications are made, the data is assigned after pressing the OK button. The menu item Attributes Edit nodes Pick can be used to investigate individual nodes to confirm that the POTE attribute are assigned at the north-eastern boundary, the VORF attribute at the nodes of the stream, the GLEI attribute at the nodes of the lake and the KNOT attribute at the three wells.

Open the View Show Attributes Attributes… menu item or click the Isolines/area plots/values... toolbar button. The following window appears,

Attribute display

To display the fixed potential heads select the POTE attribute in the Attribute dropdown box. By using the default "Circles" display type and pressing OK, it becomes clear that not all nodes of the north-eastern boundary have a potential value. This is due to the accuracy parameters of the data assignment.

Illustration of the allocated (not yet complete) potential heads

If we now reassign POTE from the structures (Select the structure with the POTE attribute via the Structure Assign List… menu item) with the following precision parameters:

Specification of the accuracy parameters

The display is then updated automatically and shows that the attribute has successfully been assigned to all the nodes on the north-eastern boundary.

The completeness of the assignment should also be checked for the GLEI data type of the lake nodes. By default, GLEI cannot be displayed with circles as it is displayed as a polyline by default. However, it can still be displayed with circles by making a workaround via another data type (a nodal type such as, e.g., 1KON, KKKK). With Attributes Copy Attribute-wise... GLEI can be copied to KKKK, and can then be displayed as circles. Once the check has been completed, the auxiliary data (KKKK) should be deleted again.

Copying attributes

The next step is assignment through interpolation of external data formats