Ground infiltration formula (Water Overlay): Difference between revisions

Revision as of 12:46, 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.

d_{u}=B_{c}-WL_{underground}

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

r=W_{unsat}/d_{u}

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

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

Finally, calculate the actual amount of water infiltrating.

\Delta w=d_{i}\cdot r

Where:

\Delta w

= The underground infiltration which takes place.

\Delta t

= Computational timestep.

d_{u}

= The height of the unsaturated zone.

r

= 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.

B_{c}

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

I_{u}

= The GROUND_INFILTRATION_MD of the underground terrain type.

@@ Line 2: / Line 2: @@
 First the height of the unsaturated zone is calculated.
-: <math>d_{u} = H_{surface} - WL_{underground}</math>
+: <math>d_{u} = B_{c} - WL_{underground}</math>
 Then the ratio of water amount to unsaturated height is calculated.
@@ Line 8: / Line 8: @@
 Then calculate the distance of the unsaturated zone which can infiltrate.
-: <math>d_{i} = min( d_{u} , \Delta t \cdot I_{und} )</math>
+: <math>d_{i} = min( d_{u} , \Delta t \cdot I_{u} )</math>
 Finally, calculate the actual amount of water infiltrating.
@@ Line 14: / Line 14: @@
 Where:
-* <math>\Delta w</math> = The underground infiltration which takes place.
+: <math>\Delta w</math> = The underground infiltration which takes place.
-* <math>\Delta t</math> = Computational timestep.
+: <math>\Delta t</math> = Computational timestep.
-* <math>d_{u}</math> = The height of the unsaturated zone.
+: <math>d_{u}</math> = The height of the unsaturated zone.
-* <math>r</math> = Ratio of water to height in the unsaturated zone.
+: <math>r</math> = Ratio of water to height in the unsaturated zone.
-* <math>d_{i}</math> = The height distance 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.
+: <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.
-* <math>WL_{underground}</math> = 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}}.
-* <math>H_{surface}</math> = The [[Terrain height (Water Overlay)|terrain height]] in the cell, relative to {{datum}}.
+: <math>B_c</math> = the datum height of the surface of cell c, set by the [[Elevation (Water Overlay)|elevation]] or a [[Terrain elevation prequel (Water Overlay)|Terrain elevation prequel]].
-* <math>I_{und}</math> = The [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]] of the underground terrain type.
+: <math>I_{u}</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 12:46, 25 January 2024

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