Ground infiltration formula (Water Overlay): Difference between revisions

Revision as of 12:52, 25 January 2024

The infiltration from the unsaturated zone to the saturated zone is calculated per cell.

First the height of the unsaturated zone is calculated.

d_{u}=B_{c}-w_{g}

Then the ratio of water amount to unsaturated height is calculated.

r=\Delta w_{u}/d_{u}

Then we calculate the distance of the unsaturated zone which can infiltrate.

d_{i}=min(d_{u},\Delta t\cdot I_{g})

Finally, calculate the actual amount of water infiltrating.

\Delta w_{i}=d_{i}\cdot r

Where:

w_{g}

B_{c}

= the datum height of the surface of cell c, set by the elevation or a Terrain elevation prequel.

d_{u}

= The height of the unsaturated zone.

\Delta w_{u}

= The amount of water in the unsaturated zone. The height of the water column if the equivalent amount of water was placed on the surface.

r

= Ratio of water to height in the unsaturated zone.

\Delta t

= Computational timestep.

I_{g}

= The GROUND_INFILTRATION_MD of the underground terrain type.

d_{i}

= The height distance in the unsaturated zone which can be subject to infiltration to the saturated zone.

\Delta w_{i}

= The infiltration which takes place from the unsaturated zone to the saturated zone.

@@ Line 7: / Line 7: @@
 : <math>r = \Delta w_u/d_{u}</math>
-Then calculate the distance of the unsaturated zone which can infiltrate.
+Then we calculate the distance of the unsaturated zone which can infiltrate.
 : <math>d_{i} = min( d_{u} , \Delta t \cdot I_{g} )</math>