Groundwater level.

In a 1D calculation this record should be given value of the groundwater level. The groundwater is below that -value.

In a 2D calculation this record should be given sets of which specify the level of the groundwater at several locations; In 2D you need to give the sets as follows:

- specify sets for increasing

In 3D the phreatic line is specified as follows. Denote the lowest x with x_0, the next higher x with x_1 etc. Denote the lowest y with y_0, the next higher y with y_1 etc. Denote the phreatic level z value for x_i y_j with z_ij. Then give the following:

- x_0 y_0 z_00 x_1 y_0 z_10 etc.
- x_0 y_1 z_01 x_1 y_1 z_11 etc.
- etc.

In nodes above the phreatic level the pressure will be set to zero during the calculation.

As a special option in 2D and 3D, you can specify one value only, which
sets a constant phreatic level of that value everywhere.
In this special case, you do not need to specify **groundflow_phreaticlevel_n**.