Attributes: MXKE for max. exfiltration rates [m³/TU/m] (polyline), MXEE for max. exfiltration rates [m³/TU/m²] (elements, horizontal and 3D models only), MXKI for max. infiltration rates [m³/TU/m] (polyline), MXEI for max. infiltration rates [m³/TU/m²] (elements, horizontal and 3D models only)

These values define maximum infiltration and exfiltration rates for leakage relationships. Limiting the rate along a polyline requires a value per unit length [m³/TU/m]. The maximum rate for the single nodes is obtained by multiplying by the proportional distance. The distance is defined as the sum of half the distances to the adjacent nodes. That's why the correct order of the nodes is very important! The maximum rate for an element has the unit [m³/TU/m²]. It is obtained by multiplying by the corresponding element area. Maximum infiltration rates can also be defined with the help of tear-off heights (data type ABRI with water course level (VORF)).

 

Examples:

MXKI = 0 means, that no water infiltrates into the groundwater from these nodes.

MXEI = 0 means, that no water infiltrates into the groundwater from these elements.

MXKE = 0 means, that no water from the groundwater reach these nodes.

MXEE = 0 means, that no water from the groundwater reach these elements.

 

(In case of inverse modelling, maximum infiltration and exfiltration rates are not available.)

The relationship of the leakage parameters illustrates the following graphic:

 

Relationship of the leakage parameters

 

If in a model maximum in- and/or exfiltration rates are assigned an iteration is done automatically during any flow calculation. Exceeds the calculated leakage rate at a node or element the maximum in- or exfiltration rate, the leakage boundary condition is switched off and the appropriate maximum rate is set as new boundary condition. The iteration is continued until the conditions are fulfilled for all nodes and elements.

The leakage limitations can be defined as transient boundary condition as well using the attributes KMKE and KMKI.