Ground infiltration formula (Water Overlay)

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

First the height of the unsaturated zone is calculated.

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle H_{unsat} = H_{surface} - WL_{underground}}

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

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle S = W_{unsat}/H_{unsat}}

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

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

Finally, calculate the actual amount of water infiltrating.

$\Delta w=C_{inf}\cdot S$

Where:

• $\Delta w$ = The underground infiltration which takes place.
• $\Delta t$ = Computational timestep.

• Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle H_{unsat}} = The height of the unsaturated zone.
• Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle S} = Ratio of water to height in the unsaturated zone.
• Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle C_{inf}} = The height in the unsaturated zone which can be subject to infiltration to the saturated zone.

• Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 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.
• Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle WL_{underground}} = The groundwater level, relative to datum.
• Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle H_{surface}} = The terrain height in the cell, relative to datum.
• Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle I_{und}} = The GROUND_INFILTRATION_MD of the underground terrain type.

Related

The following topics are related to this formula.

Formulas

Groundwater level formula

Surface infiltration formula

Underground seepage formula

Models

Underground model

Infiltration model

Tracer flow model

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