Ground flow formula (Water Overlay) - Revision history

Rudolf@tygron.nl at 14:30, 17 October 2025

2025-10-17T14:30:37Z

← Older revision		Revision as of 14:30, 17 October 2025
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	Ground flow is different from surface flow, since it has to account for the slowdown and porousness of the medium. In general, horizontal ground flow is calculated using formulas described in Harbaugh 2005<ref ~~name="~~Harbaugh~~"/><~~ref ~~name="~~Modflow~~"/>~~. However, when an [[Aquifer (Water_Overlay)\|aquifer]] is present, the [[ground flow formula (Water Overlay)#Aquifer formula\|Aquifer formula]] is applied.		Ground flow is different from surface flow, since it has to account for the slowdown and porousness of the medium. In general, horizontal ground flow is calculated using formulas described in Harbaugh 2005{{ref\|Harbaugh}}{{ref\|Modflow}}. However, when an [[Aquifer (Water_Overlay)\|aquifer]] is present, the [[ground flow formula (Water Overlay)#Aquifer formula\|Aquifer formula]] is applied.

	It depends on the configuration of the [[Hydraulic conductivity with thickness (Water Overlay)\|HYDRAULIC_CONDUCTIVITY_WITH_THICKNESS]] attribute value in the [[Water Overlay]] what Hydraulic Conductivity formula is used:		It depends on the configuration of the [[Hydraulic conductivity with thickness (Water Overlay)\|HYDRAULIC_CONDUCTIVITY_WITH_THICKNESS]] attribute value in the [[Water Overlay]] what Hydraulic Conductivity formula is used:
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	\|references=		\|references=
	<references>		<references>
	<ref name=~~"Modflow">~~Langevin, C.D., Hughes, J.D., Banta, E.R., Niswonger, R.G., Panday, Sorab, and Provost, A.M. (2017) ~~∙ Documentation for the MODFLOW 6 Groundwater Flow Model: U.S. Geological Survey Techniques and Methods~~, book 6, ~~chap.~~ A55 ~~∙ p 31 ∙ found at:~~ https://pubs.usgs.gov/publication/tm6A55 ~~(last visited~~ 04-02-2025~~)</~~ref>		{{ref\|Modflow
	~~<ref~~ name=~~"Harbaugh">Harbaugh, A.W., 2005,~~ MODFLOW-2005, the U.S. Geological Survey modular ground-water model-the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16, ~~variously paginated~~.~~</ref>~~		\|name=Documentation for the MODFLOW 6 Groundwater Flow Model: U.S. Geological Survey Techniques and Methods
			\|author=Langevin, C.D., Hughes, J.D., Banta, E.R., Niswonger, R.G., Panday, Sorab, and Provost, A.M. (2017)
			\|page=31, of book 6, chapter A55
			\|source=
			\|link=https://pubs.usgs.gov/publication/tm6A55
			\|lastvisit=04-02-2025
			}}
			{{ref\|Harbaugh
			\|name=MODFLOW-2005, the U.S. Geological Survey modular ground-water model-the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16
			\|author=>Harbaugh, A.W., 2005
			\|page=various
			\|source=
			\|link=
			\|lastvisit=
			}}
	</references>		</references>
	}}		}}

	{{WaterOverlay formula nav}}		{{WaterOverlay formula nav}}

Frank@tygron.nl at 15:28, 4 February 2025

2025-02-04T15:28:50Z

← Older revision		Revision as of 15:28, 4 February 2025
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	\|references=		\|references=
	<references>		<references>
	<ref name="Modflow">Langevin, C.D., Hughes, J.D., Banta, E.R., Niswonger, R.G., Panday, Sorab, and Provost, A.M. (2017) ∙ Documentation for the MODFLOW 6 Groundwater Flow Model: U.S. Geological Survey Techniques and Methods, book 6, chap. A55 ∙ p 31 ∙ found at: https://~~doi~~.~~org~~/~~10.3133~~/tm6A55 (last visited ~~2019~~-02-04)</ref>		<ref name="Modflow">Langevin, C.D., Hughes, J.D., Banta, E.R., Niswonger, R.G., Panday, Sorab, and Provost, A.M. (2017) ∙ Documentation for the MODFLOW 6 Groundwater Flow Model: U.S. Geological Survey Techniques and Methods, book 6, chap. A55 ∙ p 31 ∙ found at: https://pubs.usgs.gov/publication/tm6A55 (last visited 04-02-2025)</ref>
	<ref name="Harbaugh">Harbaugh, A.W., 2005, MODFLOW-2005, the U.S. Geological Survey modular ground-water model-the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16, variously paginated.</ref>		<ref name="Harbaugh">Harbaugh, A.W., 2005, MODFLOW-2005, the U.S. Geological Survey modular ground-water model-the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16, variously paginated.</ref>
	</references>		</references>

Frank@tygron.nl: /* Aquifer formula */

2024-03-05T13:29:13Z

Aquifer formula

← Older revision		Revision as of 13:29, 5 March 2024
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	: <math>{KD}_a</math> = The [[Aquifer kd (Water Overlay)\|AQUIFER_KD]] attribute of aquifer.		: <math>{KD}_a</math> = The [[Aquifer kd (Water Overlay)\|AQUIFER_KD]] attribute of aquifer.
	: <math>\Delta x</math> = Size of grid cell.		: <math>\Delta x</math> = Size of grid cell.
	: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)\|timestep]].		: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)\|timestep]] in seconds.
	: <math>w_{n,t}</math> = Ground water level in cell <math>n</math> at time <math>t</math>;		: <math>w_{n,t}</math> = Ground water level in cell <math>n</math> at time <math>t</math>;
	: <math>z_a</math> = [[Aquifer datum (Water Overlay)\|the datum height of the aquifer]] at the cell.		: <math>z_a</math> = [[Aquifer datum (Water Overlay)\|the datum height of the aquifer]] at the cell.

Frank@tygron.nl: /* Hydraulic Conductivity with Thickness */

2024-03-05T13:29:01Z

Hydraulic Conductivity with Thickness

← Older revision		Revision as of 13:29, 5 March 2024
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	: <math>KD_n</math> = The hydraulic conductivity of the cell, multiplied with the thickness of the layer, defined in [[Terrain hydraulic conductivity with thickness md (Water Overlay)\|HYDRAULIC_CONDUCTIVITY_WITH_THICKNESS_MD]] of the ground terrain.		: <math>KD_n</math> = The hydraulic conductivity of the cell, multiplied with the thickness of the layer, defined in [[Terrain hydraulic conductivity with thickness md (Water Overlay)\|HYDRAULIC_CONDUCTIVITY_WITH_THICKNESS_MD]] of the ground terrain.
	: <math>\Delta w</math> = Ground water level difference at time <math>t</math>.		: <math>\Delta w</math> = Ground water level difference at time <math>t</math>.
	: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)\|timestep]].		: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)\|timestep]] in seconds.
	: <math>\Delta x</math> = Size of grid cell.		: <math>\Delta x</math> = Size of grid cell.
	: <math>V_{KD,t}</math> = The amount of water to be transported at time <math>t</math> between one cell and the other.		: <math>V_{KD,t}</math> = The amount of water to be transported at time <math>t</math> between one cell and the other.

Frank@tygron.nl: /* Hydraulic Conductivity without Thickness */

2024-03-05T13:28:51Z

Hydraulic Conductivity without Thickness

← Older revision		Revision as of 13:28, 5 March 2024
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	: <math>A_{c,t}</math> = Area of conductance at time <math>t</math>.		: <math>A_{c,t}</math> = Area of conductance at time <math>t</math>.
	: <math>\Delta w</math> = Ground water level difference at time <math>t</math>.		: <math>\Delta w</math> = Ground water level difference at time <math>t</math>.
	: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)\|timestep]].		: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)\|timestep]] in seconds.
	: <math>\Delta x</math> = Size of grid cell.		: <math>\Delta x</math> = Size of grid cell.
	: <math>\bar{w_{t}}</math> = Averaged ground water level at time <math>t</math>, based on water levels in ground, [[Terrain water storage percentage (Water Overlay)\|WATER_STORAGE_PERCENTAGE]] and potentially the [[Surface water level formula (Water Overlay)\|surface water level]], when the ground is filled to the top.		: <math>\bar{w_{t}}</math> = Averaged ground water level at time <math>t</math>, based on water levels in ground, [[Terrain water storage percentage (Water Overlay)\|WATER_STORAGE_PERCENTAGE]] and potentially the [[Surface water level formula (Water Overlay)\|surface water level]], when the ground is filled to the top.

Frank@tygron.nl: /* Hydraulic Conductivity without Thickness */

2024-03-05T13:06:34Z

Hydraulic Conductivity without Thickness

← Older revision		Revision as of 13:06, 5 March 2024
Line 26:		Line 26:
	: <math>A_{c,t}</math> = Area of conductance at time <math>t</math>.		: <math>A_{c,t}</math> = Area of conductance at time <math>t</math>.
	: <math>\Delta w</math> = Ground water level difference at time <math>t</math>.		: <math>\Delta w</math> = Ground water level difference at time <math>t</math>.
	: <math>\Delta t</math> = Computational timestep.		: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)\|timestep]].
	: <math>\Delta x</math> = Size of grid cell.		: <math>\Delta x</math> = Size of grid cell.
	: <math>\bar{w_{t}}</math> = Averaged ground water level at time <math>t</math>, based on water levels in ground, [[Terrain water storage percentage (Water Overlay)\|WATER_STORAGE_PERCENTAGE]] and potentially the [[Surface water level formula (Water Overlay)\|surface water level]], when the ground is filled to the top.		: <math>\bar{w_{t}}</math> = Averaged ground water level at time <math>t</math>, based on water levels in ground, [[Terrain water storage percentage (Water Overlay)\|WATER_STORAGE_PERCENTAGE]] and potentially the [[Surface water level formula (Water Overlay)\|surface water level]], when the ground is filled to the top.

Frank@tygron.nl: /* Hydraulic Conductivity with Thickness */

2024-03-05T13:06:25Z

Hydraulic Conductivity with Thickness

← Older revision		Revision as of 13:06, 5 March 2024
Line 45:		Line 45:
	: <math>KD_n</math> = The hydraulic conductivity of the cell, multiplied with the thickness of the layer, defined in [[Terrain hydraulic conductivity with thickness md (Water Overlay)\|HYDRAULIC_CONDUCTIVITY_WITH_THICKNESS_MD]] of the ground terrain.		: <math>KD_n</math> = The hydraulic conductivity of the cell, multiplied with the thickness of the layer, defined in [[Terrain hydraulic conductivity with thickness md (Water Overlay)\|HYDRAULIC_CONDUCTIVITY_WITH_THICKNESS_MD]] of the ground terrain.
	: <math>\Delta w</math> = Ground water level difference at time <math>t</math>.		: <math>\Delta w</math> = Ground water level difference at time <math>t</math>.
	: <math>\Delta t</math> = Computational timestep.		: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)\|timestep]].
	: <math>\Delta x</math> = Size of grid cell.		: <math>\Delta x</math> = Size of grid cell.
	: <math>V_{KD,t}</math> = The amount of water to be transported at time <math>t</math> between one cell and the other.		: <math>V_{KD,t}</math> = The amount of water to be transported at time <math>t</math> between one cell and the other.

Frank@tygron.nl: /* Aquifer formula */

2024-03-05T13:06:16Z

Aquifer formula

← Older revision		Revision as of 13:06, 5 March 2024
Line 64:		Line 64:
	: <math>{KD}_a</math> = The [[Aquifer kd (Water Overlay)\|AQUIFER_KD]] attribute of aquifer.		: <math>{KD}_a</math> = The [[Aquifer kd (Water Overlay)\|AQUIFER_KD]] attribute of aquifer.
	: <math>\Delta x</math> = Size of grid cell.		: <math>\Delta x</math> = Size of grid cell.
	: <math>\Delta t</math> = Computational [[Timestep (Water Overlay)\|timestep]].		: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)\|timestep]].
	: <math>w_{n,t}</math> = Ground water level in cell <math>n</math> at time <math>t</math>;		: <math>w_{n,t}</math> = Ground water level in cell <math>n</math> at time <math>t</math>;
	: <math>z_a</math> = [[Aquifer datum (Water Overlay)\|the datum height of the aquifer]] at the cell.		: <math>z_a</math> = [[Aquifer datum (Water Overlay)\|the datum height of the aquifer]] at the cell.

Frank@tygron.nl: /* Aquifer formula */

2024-03-05T13:05:56Z

Aquifer formula

← Older revision		Revision as of 13:05, 5 March 2024
Line 64:		Line 64:
	: <math>{KD}_a</math> = The [[Aquifer kd (Water Overlay)\|AQUIFER_KD]] attribute of aquifer.		: <math>{KD}_a</math> = The [[Aquifer kd (Water Overlay)\|AQUIFER_KD]] attribute of aquifer.
	: <math>\Delta x</math> = Size of grid cell.		: <math>\Delta x</math> = Size of grid cell.
	: <math>\Delta t</math> = Computational timestep.		: <math>\Delta t</math> = Computational [[Timestep (Water Overlay)\|timestep]].
	: <math>w_{n,t}</math> = Ground water level in cell <math>n</math> at time <math>t</math>;		: <math>w_{n,t}</math> = Ground water level in cell <math>n</math> at time <math>t</math>;
	: <math>z_a</math> = [[Aquifer datum (Water Overlay)\|the datum height of the aquifer]] at the cell.		: <math>z_a</math> = [[Aquifer datum (Water Overlay)\|the datum height of the aquifer]] at the cell.

Frank@tygron.nl: /* Aquifer formula */

2024-03-05T13:05:15Z

Aquifer formula

← Older revision		Revision as of 13:05, 5 March 2024
Line 61:		Line 61:

	Where:		Where:
	: <math>w_{n,t}</math> = Ground water level ~~in cell <math>n</math>~~ at time <math>t</math>;		: <math>\Delta w_{t}</math> = Ground water level difference between the two adjacent cells at time <math>t</math>;
	: <math>{KD}_a</math> = The [[Aquifer kd (Water Overlay)\|AQUIFER_KD]] attribute of aquifer.		: <math>{KD}_a</math> = The [[Aquifer kd (Water Overlay)\|AQUIFER_KD]] attribute of aquifer.
	: <math>\Delta x</math> = Size of grid cell.		: <math>\Delta x</math> = Size of grid cell.
	: <math>\Delta t</math> = Computational timestep.		: <math>\Delta t</math> = Computational timestep.
			: <math>w_{n,t}</math> = Ground water level in cell <math>n</math> at time <math>t</math>;
	: <math>z_a</math> = [[Aquifer datum (Water Overlay)\|the datum height of the aquifer]] at the cell.		: <math>z_a</math> = [[Aquifer datum (Water Overlay)\|the datum height of the aquifer]] at the cell.
			: <math>V_{K(D),t}</math> = The calculated amount of water to be transported at time <math>t</math> between one cell and the other.
	: <math>V_{a,t}</math> = Volume in <math>m^{3}</math> that flows between the two adjacent cells due to the aquifer at time <math>t</math>.		: <math>V_{a,t}</math> = Volume in <math>m^{3}</math> that flows between the two adjacent cells due to the aquifer at time <math>t</math>.
	~~: <math>\Delta w_{t}</math> = Ground water level difference between the two adjacent cells at time <math>t</math>;~~
	~~: <math>V_{K(D),t}</math> = The calculated amount of water to be transported at time <math>t</math> between one cell and the other.~~

	{{article end		{{article end