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 | * WL<sub>underground</sub> = The 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 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. | ||
{{Template:WaterOverlay_nav}} | {{Template:WaterOverlay_nav}} | ||
{{Water Module buttons}} | {{Water Module buttons}} | ||
Revision as of 08:16, 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.
