Surface model (Water Overlay) - Revision history

Rudolf@tygron.nl: /* Microrelief and minimum flow threshold */

2026-02-25T13:19:38Z

Microrelief and minimum flow threshold

← Older revision		Revision as of 13:19, 25 February 2026
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	\|link=https://www.tuwien.at/index.php?eID=dumpFile&t=f&f=150915&token=e51c85712b7e70bcb769575d03f4680753d55f01~~, http://visdom.at/media/pdf/publications/Poster.pdf~~		\|link=https://www.tuwien.at/index.php?eID=dumpFile&t=f&f=150915&token=e51c85712b7e70bcb769575d03f4680753d55f01
	\|lastvisit=2026-02-25		\|lastvisit=2026-02-25
	}}		}}

Rudolf@tygron.nl at 11:23, 25 February 2026

2026-02-25T11:23:27Z

← Older revision		Revision as of 11:23, 25 February 2026
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	\|page=		\|page=
	\|source=		\|source=
	\|link=~~http~~://~~www.math~~.tamu.edu/~gpetrova/KPSV.pdf		\|link=https://people.tamu.edu/~gpetrova//KPSV.pdf
	\|lastvisit=~~2019~~-04-11		\|lastvisit=2026-02-25
	}}		}}
	</references>		</references>

Rudolf@tygron.nl at 11:19, 25 February 2026

2026-02-25T11:19:00Z

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	\|link=https://www.tuwien.at/index.php?eID=dumpFile&t=f&f=150915&token=e51c85712b7e70bcb769575d03f4680753d55f01, http://visdom.at/media/pdf/publications/Poster.pdf		\|link=https://www.tuwien.at/index.php?eID=dumpFile&t=f&f=150915&token=e51c85712b7e70bcb769575d03f4680753d55f01, http://visdom.at/media/pdf/publications/Poster.pdf
	\|lastvisit=~~2015~~-02-25		\|lastvisit=2026-02-25
	}}		}}
	{{ref\|Kurganov2		{{ref\|Kurganov2

Rudolf@tygron.nl at 11:18, 25 February 2026

2026-02-25T11:18:16Z

← Older revision		Revision as of 11:18, 25 February 2026
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	\|page=		\|page=
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	\|link=~~http~~://~~citeseerx~~.~~ist~~.~~psu~~.~~edu/viewdoc/download~~?~~doi~~=~~10.1.1.700.7977~~&~~rep~~=~~rep1~~&~~type~~=~~pdf~~, http://visdom.at/media/pdf/publications/Poster.pdf		\|link=https://www.tuwien.at/index.php?eID=dumpFile&t=f&f=150915&token=e51c85712b7e70bcb769575d03f4680753d55f01, http://visdom.at/media/pdf/publications/Poster.pdf
	\|lastvisit=~~2018~~-06-29		\|lastvisit=2015-02-25
	}}		}}
	{{ref\|Kurganov2		{{ref\|Kurganov2

Rudolf@tygron.nl at 14:39, 17 October 2025

2025-10-17T14:39:34Z

← Older revision		Revision as of 14:39, 17 October 2025
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	__NOTOC__		__NOTOC__
	[[File:Waterlevel_schematic.png\|300px\|thumb\|right\|Fig. 1. For each grid cell:<br>''B'' = bottom elevation<br>''h'' = water depth<br>''w'' = water surface elevation]]		[[File:Waterlevel_schematic.png\|300px\|thumb\|right\|Fig. 1. For each grid cell:<br>''B'' = bottom elevation<br>''h'' = water depth<br>''w'' = water surface elevation]]
	[[File:Inundation overlay 04 HWP(1).PNG\|thumb\|250px\|Fig. 2. A 2-D grid-based representation of average water depths, discharges and bathymetry in a case where the middle cell is fully flooded in the y-dimension, but only partially flooded in the x-dimension. Blue solid and red dashed lines denote the waterlines and bathymetry slopes in both dimensions, respectively. For a bilinear reconstruction, the cell averages coincide with the values at the cell centers, while bathymetry is approximated by its values at the cell vertices.<ref ~~name="~~Horvath~~"/>~~]]		[[File:Inundation overlay 04 HWP(1).PNG\|thumb\|250px\|Fig. 2. A 2-D grid-based representation of average water depths, discharges and bathymetry in a case where the middle cell is fully flooded in the y-dimension, but only partially flooded in the x-dimension. Blue solid and red dashed lines denote the waterlines and bathymetry slopes in both dimensions, respectively. For a bilinear reconstruction, the cell averages coincide with the values at the cell centers, while bathymetry is approximated by its values at the cell vertices.{{ref\|Horvath}}]]
	[[File:Inundation overlay 04 HWP(2).PNG\|thumb\|250px\|Fig. 3. Continuous bathymetry function (green line) and its piecewise linear approximation (brown dots). The approximated function values equal to the continuous ones at the cell vertices (green dots). The cell average value (blue dot) equals both the average value of the vertex values (green dots) and the average value of the values at the cell interface midpoints (brown dots).<ref ~~name="~~Horvath~~"/>~~]]		[[File:Inundation overlay 04 HWP(2).PNG\|thumb\|250px\|Fig. 3. Continuous bathymetry function (green line) and its piecewise linear approximation (brown dots). The approximated function values equal to the continuous ones at the cell vertices (green dots). The cell average value (blue dot) equals both the average value of the vertex values (green dots) and the average value of the values at the cell interface midpoints (brown dots).{{ref\|Horvath}}]]
	The [[Water Module]]'s primary function is simulating two-dimensional flow of water across the surface. In order to do this, the project area is first discretized into ''x'' by ''y'' cells depending on the configured [[grid cell size]]. Secondly, water is initialized in the model. Finally, a set of rules is required that describes the behavior of the flow.		The [[Water Module]]'s primary function is simulating two-dimensional flow of water across the surface. In order to do this, the project area is first discretized into ''x'' by ''y'' cells depending on the configured [[grid cell size]]. Secondly, water is initialized in the model. Finally, a set of rules is required that describes the behavior of the flow.

	===Surface flow scheme===		===Surface flow scheme===
	In the model, imbalances in the water surface elevation across the grid drive the flow of water until a state of equilibrium is reached in terms of ''h'' and flux. Behavior of the flow is described by a second-order semi-discrete central-upwind scheme produced by Kurganov and Petrova (2007)<ref ~~name="~~Kurganov2~~"/>~~, which is based on the 2-D Saint-Venant equations (a.k.a. shallow water equations):		In the model, imbalances in the water surface elevation across the grid drive the flow of water until a state of equilibrium is reached in terms of ''h'' and flux. Behavior of the flow is described by a second-order semi-discrete central-upwind scheme produced by Kurganov and Petrova (2007){{ref\|Kurganov2}}, which is based on the 2-D Saint-Venant equations (a.k.a. shallow water equations):

	:<math>		:<math>
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	====Shoreline reconstruction====		====Shoreline reconstruction====
	This scheme is further extended with the shoreline reconstruction method by Bollerman et al (2014), which ensures better numerical stability at the wetting and drying fronts of a flood wave<ref ~~name="~~Bollerman~~"/>~~. An elaborate explanation is provided by Horváth et al. (2014)<ref ~~name="~~Horvath~~"/>~~.		This scheme is further extended with the shoreline reconstruction method by Bollerman et al (2014), which ensures better numerical stability at the wetting and drying fronts of a flood wave{{ref\|Bollerman}}. An elaborate explanation is provided by Horváth et al. (2014){{ref\|Horvath}}.

	General sequence of computational steps:		General sequence of computational steps:
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	\|references=		\|references=
	<references>		<references>
	<ref name=~~"Bollerman">~~Bollermann, Andreas & Chen, Guoxian & Kurganov, Alexander & Noelle, Sebastian. (2014)~~. A Well-balanced Reconstruction for Wetting, Drying Fronts. IGPM Report.~~ 313~~. ∙ found at:~~ https://www.researchgate.net/publication/269417532_A_Well-balanced_Reconstruction_for_Wetting_Drying_Fronts ~~(last visited:~~ 2019-07-24~~)</~~ref>		{{ref\|Bollerman
	~~<ref~~ name=~~"Horvath">~~Zsolt Horváth, Jürgen Waser, Rui A. P. Perdigão, Artem Konev and Günter Blöschl (2014) ~~∙ A two-dimensional numerical scheme of dry/wet fronts for the Saint-Venant system of shallow water equations ∙ found at:~~ http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.700.7977&rep=rep1&type=pdf ~~and https~~://~~www.vrvis~~.at/publications/~~pdfs/PB-VRVis-2014-034~~.pdf ~~(last visited 2024~~-03-~~15)</~~ref>		\|name=A Well-balanced Reconstruction for Wetting, Drying Fronts. IGPM Report
	~~<ref~~ name=~~"Kurganov2">Kurganov A, Petrova G (2007) ∙~~ A Second-Order Well-Balanced Positivity Preserving Central-Upwind Scheme for the Saint-Venant System ~~∙ found at:~~ http://www.math.tamu.edu/~gpetrova/KPSV.pdf ~~(last visited~~ 2019-04-11~~)</ref>~~		\|author=Bollermann, Andreas & Chen, Guoxian & Kurganov, Alexander & Noelle, Sebastian. (2014)
			\|page=313
			\|source=
			\|link=https://www.researchgate.net/publication/269417532_A_Well-balanced_Reconstruction_for_Wetting_Drying_Fronts
			\|lastvisit=2019-07-24
			}}
			{{ref\|Horvath
			\|name=A two-dimensional numerical scheme of dry/wet fronts for the Saint-Venant system of shallow water equations
			\|author=Zsolt Horváth, Jürgen Waser, Rui A. P. Perdigão, Artem Konev and Günter Blöschl (2014)
			\|page=
			\|source=
			\|link=http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.700.7977&rep=rep1&type=pdf, http://visdom.at/media/pdf/publications/Poster.pdf
			\|lastvisit=2018-06-29
			}}
			{{ref\|Kurganov2
			\|name=A Second-Order Well-Balanced Positivity Preserving Central-Upwind Scheme for the Saint-Venant System
			\|author=Kurganov A, Petrova G (2007)
			\|page=
			\|source=
			\|link=http://www.math.tamu.edu/~gpetrova/KPSV.pdf
			\|lastvisit=2019-04-11
			}}
	</references>		</references>
	}}		}}

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

Maxim@tygron.com at 10:18, 15 July 2025

2025-07-15T10:18:07Z

← Older revision		Revision as of 10:18, 15 July 2025
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	{{article end		{{article end
	\|notes=		\|notes=
	* Water can be added to and removed from the described surface system by the [[Rain model (Water Overlay)\|rain]], [[~~Evaporation~~ model (Water Overlay)\|~~evaporation~~]] and [[Infiltration model (Water Overlay)\|infiltration model]], as well as certain [[Hydraulic structures (Water Overlay)\|hydraulic structures]] and [[Breach (Water Overlay)\|breach]]es.		* Water can be added to and removed from the described surface system by the [[Rain model (Water Overlay)\|rain]], [[Evapotranspiration model (Water Overlay)\|evapotranspiration]] and [[Infiltration model (Water Overlay)\|infiltration model]], as well as certain [[Hydraulic structures (Water Overlay)\|hydraulic structures]] and [[Breach (Water Overlay)\|breach]]es.
	* In the case of [[Ground model (Water Overlay)\|subsurface flow]] a different flow system with different equations are used.		* In the case of [[Ground model (Water Overlay)\|subsurface flow]] a different flow system with different equations are used.
	* In addition to water flowing in between grid cells, water can also flow ''through'' [[Hydraulic structures (Water Overlay)\|hydraulic buildings]].		* In addition to water flowing in between grid cells, water can also flow ''through'' [[Hydraulic structures (Water Overlay)\|hydraulic buildings]].

Frank@tygron.nl: /* Microrelief and minimum flow threshold */

2024-03-15T15:27:33Z

Microrelief and minimum flow threshold

← Older revision		Revision as of 15:27, 15 March 2024
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	<references>		<references>
	<ref name="Bollerman">Bollermann, Andreas & Chen, Guoxian & Kurganov, Alexander & Noelle, Sebastian. (2014). A Well-balanced Reconstruction for Wetting, Drying Fronts. IGPM Report. 313. ∙ found at: https://www.researchgate.net/publication/269417532_A_Well-balanced_Reconstruction_for_Wetting_Drying_Fronts (last visited: 2019-07-24)</ref>		<ref name="Bollerman">Bollermann, Andreas & Chen, Guoxian & Kurganov, Alexander & Noelle, Sebastian. (2014). A Well-balanced Reconstruction for Wetting, Drying Fronts. IGPM Report. 313. ∙ found at: https://www.researchgate.net/publication/269417532_A_Well-balanced_Reconstruction_for_Wetting_Drying_Fronts (last visited: 2019-07-24)</ref>
	<ref name="Horvath">Zsolt Horváth, Jürgen Waser, Rui A. P. Perdigão, Artem Konev and Günter Blöschl (2014) ∙ A two-dimensional numerical scheme of dry/wet fronts for the Saint-Venant system of shallow water equations ∙ found at: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.700.7977&rep=rep1&type=pdf and ~~http~~://~~visdom~~.at/~~media~~/~~pdf~~/~~publications/Poster~~.pdf (last visited ~~2018~~-06-29)</ref>		<ref name="Horvath">Zsolt Horváth, Jürgen Waser, Rui A. P. Perdigão, Artem Konev and Günter Blöschl (2014) ∙ A two-dimensional numerical scheme of dry/wet fronts for the Saint-Venant system of shallow water equations ∙ found at: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.700.7977&rep=rep1&type=pdf and https://www.vrvis.at/publications/pdfs/PB-VRVis-2014-034.pdf (last visited 2024-03-15)</ref>
	<ref name="Kurganov2">Kurganov A, Petrova G (2007) ∙ A Second-Order Well-Balanced Positivity Preserving Central-Upwind Scheme for the Saint-Venant System ∙ found at: http://www.math.tamu.edu/~gpetrova/KPSV.pdf (last visited 2019-04-11)</ref>		<ref name="Kurganov2">Kurganov A, Petrova G (2007) ∙ A Second-Order Well-Balanced Positivity Preserving Central-Upwind Scheme for the Saint-Venant System ∙ found at: http://www.math.tamu.edu/~gpetrova/KPSV.pdf (last visited 2019-04-11)</ref>
	</references>		</references>

Frank@tygron.nl: /* Microrelief and minimum flow threshold */

2024-03-04T16:43:25Z

Microrelief and minimum flow threshold

← Older revision		Revision as of 16:43, 4 March 2024
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	===Microrelief and minimum flow threshold===		===Microrelief and minimum flow threshold===
	[[File:water_overlay_surface_model_microrelief_flow_threshold.png\|thumb\|right\|[[Water microrelief m (Water Overlay)\|Microrelief]], optional [[Microrelief storage fraction (Water Overlay)\| microrelief storage fraction]] and the minimum flow threshold.]]		[[File:water_overlay_surface_model_microrelief_flow_threshold.png\|thumb\|right\|[[Water microrelief m (Water Overlay)\|Microrelief]], optional [[Microrelief storage fraction (Water Overlay)\| microrelief storage fraction]] and the minimum flow threshold.]]
	For water to flow from a cell to its neighbors, the height of a water column needs to be at least 0.5mm. We call this the ''minimum flow threshold''. However, if microrelief is defined, this minimum flow threshold of a cell is potentially raised to the amount specified for microrelief. Microrelief can be specified by a function's [[Water microrelief m (Water Overlay)\|microrelief]] or terrain's [[Terrain water microrelief m (Water Overlay)\|microrelief]], or using a grid overlay for the [[Microrelief prequel (Water Overlay)\|Microrelief prequel]].		For water to flow from a cell to its neighbors, the height of a water column needs to be at least 0.5mm. We call this the ''minimum flow threshold''. However, if microrelief is defined, this minimum flow threshold of a cell is potentially raised to the amount specified for microrelief. Microrelief can be specified by a function's [[Water microrelief m (Water Overlay)\|microrelief]] or terrain's [[Terrain water microrelief m (Water Overlay)\|microrelief]], or using a grid overlay for the [[Microrelief prequel (Water Overlay)\|Microrelief prequel]]. Furthermore an optional [[Microrelief storage fraction (Water Overlay)\|Microrelief storage fraction]] can be set, which will be applied to the microrelief threshold.

Frank@tygron.nl: /* Microrelief and minimum flow threshold */

2024-03-04T16:41:08Z

Microrelief and minimum flow threshold

← Older revision		Revision as of 16:41, 4 March 2024
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	===Microrelief and minimum flow threshold===		===Microrelief and minimum flow threshold===
	[[File:water_overlay_surface_model_microrelief_flow_threshold.png\|thumb\|right\|Microrelief and minimum flow threshold]]		[[File:water_overlay_surface_model_microrelief_flow_threshold.png\|thumb\|right\|[[Water microrelief m (Water Overlay)\|Microrelief]], optional [[Microrelief storage fraction (Water Overlay)\| microrelief storage fraction]] and the minimum flow threshold.]]
	For water to flow from a cell to its neighbors, the height of a water column needs to be at least 0.5mm. We call this the ''minimum flow threshold''. However, if microrelief is defined, this minimum flow threshold of a cell is potentially raised to the amount specified for microrelief. Microrelief can be specified by a function's [[Water microrelief m (Water Overlay)\|microrelief]] or terrain's [[Terrain water microrelief m (Water Overlay)\|microrelief]], or using a grid overlay for the [[Microrelief prequel (Water Overlay)\|Microrelief prequel]].		For water to flow from a cell to its neighbors, the height of a water column needs to be at least 0.5mm. We call this the ''minimum flow threshold''. However, if microrelief is defined, this minimum flow threshold of a cell is potentially raised to the amount specified for microrelief. Microrelief can be specified by a function's [[Water microrelief m (Water Overlay)\|microrelief]] or terrain's [[Terrain water microrelief m (Water Overlay)\|microrelief]], or using a grid overlay for the [[Microrelief prequel (Water Overlay)\|Microrelief prequel]].

Frank@tygron.nl: /* Microrelief and minimum flow threshold */

2024-03-04T15:45:17Z

Microrelief and minimum flow threshold

← Older revision		Revision as of 15:45, 4 March 2024
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	===Microrelief and minimum flow threshold===		===Microrelief and minimum flow threshold===
			[[File:water_overlay_surface_model_microrelief_flow_threshold.png\|thumb\|right\|Microrelief and minimum flow threshold]]
	For water to flow from a cell to its neighbors, the height of a water column needs to be at least 0.5mm. We call this the ''minimum flow threshold''. However, if microrelief is defined, this minimum flow threshold of a cell is potentially raised to the amount specified for microrelief. Microrelief can be specified by a function's [[Water microrelief m (Water Overlay)\|microrelief]] or terrain's [[Terrain water microrelief m (Water Overlay)\|microrelief]], or using a grid overlay for the [[Microrelief prequel (Water Overlay)\|Microrelief prequel]].		For water to flow from a cell to its neighbors, the height of a water column needs to be at least 0.5mm. We call this the ''minimum flow threshold''. However, if microrelief is defined, this minimum flow threshold of a cell is potentially raised to the amount specified for microrelief. Microrelief can be specified by a function's [[Water microrelief m (Water Overlay)\|microrelief]] or terrain's [[Terrain water microrelief m (Water Overlay)\|microrelief]], or using a grid overlay for the [[Microrelief prequel (Water Overlay)\|Microrelief prequel]].