Surface infiltration formula (Water Overlay)

Surface infiltration is calculated per cell. First, the infiltration capacities are calculated:

${\bar {I}}_{top}={\begin{cases}{\bar {I}}_{con},&{\text{if constructions are present on top of the surface}}\\{\bar {I}}_{terrain},&{\text{otherwise}}\\\end{cases}}$

${\bar {I}}_{surface}=min({\bar {I}}_{ground},{\bar {I}}_{top})$

Then the actual infiltration:

$\Delta w_{t}=min(h_{t},{\bar {I}}_{surface}\cdot \Delta t\cdot f_{i,t})$

Where:

{\bar {I}}_{con}

= The average infiltration capacity based on constructions on top of the surface, based on GROUND_INFILTRATION_MD defined in either the building or function.

{\bar {I}}_{terrain}

= The average infiltration capacity based on the surface terrain, defined by GROUND_INFILTRATION_MD. This value should be interpreted as the vertical conductivity (Kv) of the sub-soil.