Ground infiltration formula (Water Overlay): Difference between revisions

Latest revision as of 13:49, 5 March 2024

Water can infiltrate from the unsaturated zone to the saturated zone.

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 f_{i,t}\cdot I_{g})

Finally, we calculate the actual amount of water that infiltrates from the unsaturated zone to the saturated zone.

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

Where:

w_{g}

= 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.

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 in seconds.

f_{i,t}

= The interpolated infiltration factor at time

t

. Configured using INFILTRATION_FACTOR_S.

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 1: / Line 1: @@
-Underground infiltration (from the unsaturated zone to the saturated zone) is calculated per cell.
+[[File:underground_model.jpg|thumb|right|Water can infiltrate from the unsaturated zone to the saturated zone.]]
+The infiltration from the unsaturated zone to the saturated zone is calculated per cell.
 First the height of the unsaturated zone is calculated.
-: <math>H_{unsat} = H_{surface} - WL_{underground}</math>
+: <math>d_{u} = B_{c} - w_g</math>
 Then the ratio of water amount to unsaturated height is calculated.
-: <math>S = W_{unsat}/H_{unsat}</math>
+: <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>C_{inf} = min( H_{unsat} , \Delta t \cdot I_{und} )</math>
+: <math>d_{i} = min( d_{u} , \Delta t \cdot f_{i,t} \cdot I_{g} )</math>
-Finally, calculate the actual amount of water infiltrating.
+Finally, we calculate the actual amount of water that infiltrates from the unsaturated zone to the saturated zone.
-: <math>\Delta w = C_{inf} \cdot S</math>
+: <math>\Delta w_i = d_{i} \cdot r</math>
 Where:
-* <math>\Delta w</math> = The underground infiltration which takes place.
+: <math>w_g</math> = The [[Groundwater level formula (Water Overlay)|groundwater level]], relative to {{datum}}.
-* <math>\Delta t</math> = Computational timestep.
+: <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>d_{u}</math> = The height of the unsaturated zone.
-* <math>H_{unsat}</math> = The height of the unsaturated zone.
+: <math>\Delta w_u</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>S</math> = Ratio of water to height in the unsaturated zone.
+: <math>r</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>\Delta t</math> = Computational [[Timestep formula (Water Overlay)|timestep]] in seconds.
+: <math>f_{i,t}</math> = The interpolated infiltration factor at time <math>t</math>. Configured using [[Infiltration_factor_s_(Water_Overlay)|INFILTRATION_FACTOR_S]].
-* <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>I_{g}</math> = The [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]] of the underground terrain type.
-* <math>WL_{underground}</math> = The [[Groundwater level formula (Water Overlay)|groundwater level]], relative to {{datum}}.
+: <math>d_{i}</math> = The height distance in the unsaturated zone which can be subject to infiltration to the saturated zone.
-* <math>H_{surface}</math> = The [[Terrain height (Water Overlay)|terrain height]] in the cell, relative to {{datum}}.
+: <math>\Delta w_i</math> = The infiltration which takes place from the unsaturated zone to the saturated zone.
-* <math>I_{und}</math> = The [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]] of the underground terrain type.
 ==Related==
 The following topics are related to this formula.
 ; Formulas
-: [[Groundwater level formula (Water Overlay)|Groundwater level formula]]
+: [[Groundwater level formula (Water Overlay)]]
-: [[Surface infiltration formula (Water Overlay)|Surface infiltration formula]]
+: [[Surface infiltration formula (Water Overlay)]]
-: [[Underground seepage formula (Water Overlay)|Underground seepage formula]]
+: [[Ground bottom flow formula (Water Overlay)]]
 ; Models
-: [[Underground model (Water Overlay)|Underground model]]
+: [[Ground model (Water Overlay)]]
-: [[Infiltration model (Water Overlay)|Infiltration model]]
+: [[Infiltration model (Water Overlay)]]
-: [[Tracer flow model (Water Overlay)|Tracer flow model]]
+: [[Tracer flow model (Water Overlay)]]
 {{WaterOverlay formula nav}}

Ground infiltration formula (Water Overlay): Difference between revisions

Latest revision as of 13:49, 5 March 2024

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