Ground infiltration formula (Water Overlay): Difference between revisions

Revision as of 12:43, 25 January 2024

Underground infiltration (from the unsaturated zone to the saturated zone) is calculated per cell.

First the height of the unsaturated zone is calculated.

H_{unsat}=H_{surface}-WL_{underground}

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

S=W_{unsat}/H_{unsat}

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

d_{i}=min(H_{unsat},\Delta t\cdot I_{und})

Finally, calculate the actual amount of water infiltrating.

\Delta w=d_{i}\cdot S

Where:

$H_{unsat}$ = The height of the unsaturated zone.
$S$ = Ratio of water to height in the unsaturated zone.
$d_{i}$ = The height distance in the unsaturated zone which can be subject to infiltration to the saturated zone.

$W_{unset}$ = 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.
$WL_{underground}$ = The groundwater level, relative to datum.
$H_{surface}$ = The terrain height in the cell, relative to datum.
$I_{und}$ = The GROUND_INFILTRATION_MD of the underground terrain type.

@@ Line 8: / Line 8: @@
 Then calculate the distance of the unsaturated zone which can infiltrate.
-: <math>C_{inf} = min( H_{unsat} , \Delta t \cdot I_{und} )</math>
+: <math>d_{i} = min( H_{unsat} , \Delta t \cdot I_{und} )</math>
 Finally, calculate the actual amount of water infiltrating.
-: <math>\Delta w = C_{inf} \cdot S</math>
+: <math>\Delta w = d_{i} \cdot S</math>
 Where:
@@ Line 19: / Line 19: @@
 * <math>H_{unsat}</math> = The height of the unsaturated zone.
 * <math>S</math> = Ratio of water to height in the unsaturated zone.
-* <math>C_{inf}</math> = The height in the unsaturated zone which can be subject to infiltration to the saturated zone.
+* <math>d_{i}</math> = The height distance in the unsaturated zone which can be subject to infiltration to the saturated zone.
 * <math>W_{unset}</math> = 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.