Ground infiltration formula (Water Overlay): Difference between revisions

Revision as of 17:19, 4 December 2020

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.

C_{inf}=min(H_{unsat},\Delta t\cdot I_{und})

Finally, calculate the actual amount of water infiltrating.

\Delta w=C_{inf}\cdot S

Where:

$\Delta w$ = The underground infiltration which takes place.
$\Delta t$ = Computational timestep.

$H_{unsat}$ = The height of the unsaturated zone.
$S$ = Ratio of water to height in the unsaturated zone.
$C_{inf}$ = The height 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 2: / Line 2: @@
 First the height of the unsaturated zone is calculated.
-: <math>H_{unsat} = H_{surface} - WL_{underground}''
+: <math>H_{unsat} = H_{surface} - WL_{underground}</math>
 Then the ratio of water amount to unsaturated height is calculated.
@@ Line 14: / Line 14: @@
 Where:
-* Δw = The underground infiltration which takes place.
+* <math>\Delta w</math> = The underground infiltration which takes place.
-* Δt = Computational timestep.
+* <math>\Delta t</math> = Computational timestep.
-* H<sub>unsat</sub> = The height of the unsaturated zone.
+* <math>H_{unsat}</math> = The height of the unsaturated zone.
-* S = Ratio of water to height in the unsaturated zone.
+* <math>S</math> = Ratio of water to height in the unsaturated zone.
-* C<sub>inf</sub> = The height in the unsaturated zone which can be subject to infiltration to the saturated zone.
+* <math>C_{inf}</math> = The height in the unsaturated zone which can be subject to infiltration to the saturated zone.
-* W<sub>unset</sub> = 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.
+* <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.
-* WL<sub>underground</sub> = The [[Groundwater level formula (Water Overlay)|groundwater level]], relative to {{datum}}.
+* <math>WL_{underground}</math> = The [[Groundwater level formula (Water Overlay)|groundwater level]], relative to {{datum}}.
-* H<sub>surface</sub> = The [[Terrain height (Water Overlay)|terrain height]] in the cell, relative to {{datum}}.
+* <math>H_{surface}</math> = The [[Terrain height (Water Overlay)|terrain height]] in the cell, relative to {{datum}}.
-* I<sub>und</sub> = The [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]] of the underground terrain type.
+* <math>I_{und}</math> = The [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]] of the underground terrain type.
 ==Related==

Ground infiltration formula (Water Overlay): Difference between revisions

Revision as of 17:19, 4 December 2020

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