Ground infiltration formula (Water Overlay): Difference between revisions

Revision as of 17:17, 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}''Thentheratioofwateramounttounsaturatedheightiscalculated.:<math>S=W_{unsat}/H{unsat}

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

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

Finally, calculate the actual amount of water infiltrating.

Δw = C_inf * S

Where:

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.
-: ''H<sub>unsat</sub> = H<sub>surface</sub> - WL<sub>underground</sub>''
+: <math>H_{unsat} = H_{surface} - WL_{underground}''
 Then the ratio of water amount to unsaturated height is calculated.
-: ''S = W<sub>unsat</sub>/H<sub>unsat</sub>''
+: <math>S = W_{unsat}/H{unsat}</math>
 Then calculate the distance of the unsaturated zone which can infiltrate.
-: ''C<sub>inf</sub> = min( H<sub>unsat</sub> , Δt * I<sub>und</sub> )''
+: <math>C_{inf} = min( H_{unsat} , \Delta t \cdot I_{und} )''
 Finally, calculate the actual amount of water infiltrating.