Ground infiltration formula (Water Overlay): Difference between revisions

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* 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.
* 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.
* WL<sub>underground</sub> = The groundwater level, relative to {{datum}}.
* WL<sub>underground</sub> = The [[Groundwater level formula (Water Overlay)|groundwater level]], relative to {{datum}}.
* H<sub>surface</sub> = The terrain height in the cell, relative to {{datum}}.
* H<sub>surface</sub> = 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.
* I<sub>und</sub> = The [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]] of the underground terrain type.


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Revision as of 08:17, 14 June 2019

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

First the height of the unsaturated zone is calculated.

Hunsat = Hsurface - WLunderground

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

S = Wunsat/Hunsat

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

Cinf = min( Hunsat , Δt * Iund )

Finally, calculate the actual amount of water infiltrating.

Δw = Cinf * S

Where:

  • Δw = The underground infiltration which takes place.
  • Δt = Computational timestep.
  • Hunsat = The height of the unsaturated zone.
  • S = Ratio of water to height in the unsaturated zone.
  • Cinf = The height in the unsaturated zone which can be subject to infiltration to the saturated zone.
  • Wunset = 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.
  • WLunderground = The groundwater level, relative to datum.
  • Hsurface = The terrain height in the cell, relative to datum.
  • Iund = The GROUND_INFILTRATION_MD of the underground terrain type.

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