Ground bottom flow formula (Water Overlay): Difference between revisions
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* <math>\Delta t</math> = Computational timestep in seconds. | * <math>\Delta t</math> = Computational timestep in seconds. | ||
* <math>h_{x,y}</math> = Ground water head in the grid cell. | * <math>h_{x,y}</math> = Ground water head in the grid cell. | ||
* <math>h_{d,t}</math> = ground water level (or head) of the external zone causing the seepage at time t, in meters | * <math>h_{d,t}</math> = additional ground water level (or head) of the external zone causing the seepage at time t, in meters | ||
* <math>h_{ | * <math>h_{c_{x,y}}</math> = constant ground water level (or head) of the external zone causing the seepage, in meters | ||
* <math>h_{v,t}</math> = additional variation of seepage head over time | * <math>h_{v,t}</math> = additional variation of seepage head over time | ||
* <math>c</math> = resistance of the separating layer in days | * <math>c</math> = resistance of the separating layer in days | ||
* <math>ws</math> = water storage fraction of the soil | * <math>ws</math> = water storage fraction of the soil | ||
==Notes== | |||
* <math>h_{c_{x,y}}</math> and <math>c_{x,y}</math> can both be provided as spatially variable values. | |||
* <math>h_{d,t}</math> can be provided as a set of values, variable over time. | |||
==See also== | ==See also== | ||
Revision as of 09:38, 14 August 2020
Underground seepage (from (or to) outside the project area) is calculated per cell.
The seepage is calculated using the following formula:
- 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 \Delta s = \frac{h_{d}(t) - h_{x,y}}{c_{x,y}} \cdot \frac{\Delta t}{24 \cdot 60 \cdot 60}}
The external seepage head is variable over time by the introduction of hv,t
- 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_d(t) = h_{c_{x,y}} + h_{v,t}(t)}
Finally, calculate the actual amount of water seeping into (or out of) the ground from the bottom.
Where:
- 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 \Delta s} = The underground seepage which takes place, in meters.
- 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 \Delta t} = Computational timestep in seconds.
- 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_{x,y}} = Ground water head in the grid cell.
- 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_{d,t}} = additional ground water level (or head) of the external zone causing the seepage at time t, in meters
- 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_{c_{x,y}}} = constant ground water level (or head) of the external zone causing the seepage, in meters
- 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_{v,t}} = additional variation of seepage head over time
- 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} = resistance of the separating layer in days
- 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 ws} = water storage fraction of the soil
Notes
- 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_{c_{x,y}}} and 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_{x,y}} can both be provided as spatially variable values.
- 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_{d,t}} can be provided as a set of values, variable over time.
See also
- The formula is based on the formula of Pankow for estimating seepage
- Seepage result
- Seepage geotiffs
- Seepage fluctuation