Attribute: GLEI [-]

To determine the position of a potential line (groundwater isoline), whose value is unknown, the attribute GLEI is assigned to nodes, which receive in the modelling process all the same potential value.

 

In the case of vertical models, the definition of unknown potential head is useful with pumping wells where the pumping rate is defined or should be varied. All nodes along the well beneath the water table should have the same potential head. The attribute GLEI with value = 0. is assigned to these nodes.

In case of horizontal models, GLEI can be assigned to the shore nodes of a lake where the water table depends on the ground water table.

In 3D models, GLEI is used for fully penetrating wells, because the potential head must be equal over the full length of the well.

In partial 3D models, along the border between the 2D and the 3D part, unknown equal potential heads are used to define equal potential heads over the complete depth (see chapter Creating a 2D model combined with a partial 3D model).

 

All nodes of one list have the same potential head. A list is complete, if no continuation line follows (blank in column 80).

The value in columns 1 to 14 can be used to define a constant potential difference between two nodes. The potential heads remain unknown. However, they are determined so that the difference in the potentials is equal to the prescribed value.

 

Example:

 

GLEI ks3 : nodes with equal unknown potential heads

0.00000 64- 65, 67, 66, 69, 68, 71- 73,

0.00000 75, 74,

 

Nodes 64 to 69 and 71-73 have the same potential head. Nodes 75 and 74 also have the same potential head, but the value is not necessarily equal to the previous list. Thus several different sets of data can be entered.