Attribute: POTE, [meters above reference datum] (node-wise)

Fixed potential heads are changed or assigned for the first time with POTE. To switch off the potential head boundary condition for nodes completely, the node number must be specified as negative (for any potential value). In later time steps, that same node can also be assigned a potential head again by assigning a positive node number with the corresponding potential head value.

The following rules must be adhered to for simulations with the interpolation of transient boundary conditions:

• If a fixed potential head is switched on and then switched off, the first specification with the negative node number (for switching off) must have a 'realistic' potential head, as this potential head is still required for the interpolation of the data in the intermediate times between switching on and switching off. For example, if the transient input file contains the following data:

Point of time 10 POTE 10.0 1 (on)

Point of time 20 POTE 5.0 -1 (off)

In a calculation with the interpolation of POTE in this example, the potential head values of 9.0, 8.0, 7.0 and 6.0 m would be used for the intermediate time points 12, 14, 16 and 18. The boundary condition would only be turned off at time point 20.

• If a fixed potential is switched off and then switched on again, it is only switched on at the point in time specified in the transient input file and not at a previous intermediate point in time. There is also no interpolation between the old ('switched off') and new ('switched on') potential heads at intermediate points in time.