Evapotranspiration model (Water Overlay) - Revision history

Frank@tygron.nl at 10:48, 16 December 2025

2025-12-16T10:48:05Z

← Older revision		Revision as of 10:48, 16 December 2025
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	{{article end		{{article end
	\|seealso=		\|seealso=
			<div style="column-count:2">
	* [[Ground transpiration result type (Water Overlay)]]		* [[Ground transpiration result type (Water Overlay)]]
	* [[Surface evaporation result type (Water Overlay)]]		* [[Surface evaporation result type (Water Overlay)]]
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	* [[Surface last evaporation result type (Water Overlay)]]		* [[Surface last evaporation result type (Water Overlay)]]
	* [[Last evapotranspiration result type (Water Overlay)]]		* [[Last evapotranspiration result type (Water Overlay)]]
			</div>
	==Related formulas==		==Related formulas==
	* [[Surface evaporation formula (Water Overlay)\|Surface evaporation formula]]		* [[Surface evaporation formula (Water Overlay)\|Surface evaporation formula]]

Frank@tygron.nl at 10:46, 16 December 2025

2025-12-16T10:46:48Z

← Older revision		Revision as of 10:46, 16 December 2025
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	* [[Surface evaporation result type (Water Overlay)]]		* [[Surface evaporation result type (Water Overlay)]]
	* [[Evapotranspiration result type (Water Overlay)]]		* [[Evapotranspiration result type (Water Overlay)]]
			* [[Ground last transpiration result type (Water Overlay)]]
			* [[Surface last evaporation result type (Water Overlay)]]
			* [[Last evapotranspiration result type (Water Overlay)]]
	==Related formulas==		==Related formulas==
	* [[Surface evaporation formula (Water Overlay)\|Surface evaporation formula]]		* [[Surface evaporation formula (Water Overlay)\|Surface evaporation formula]]

Frank@tygron.nl at 10:46, 16 December 2025

2025-12-16T10:46:12Z

← Older revision		Revision as of 10:46, 16 December 2025
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	If, during any timestep, the amount of water present is less than what is calculated to evaporate, the water present will evaporate, but because there was not enough water to evaporate, the actual total amount of evaporation will be less than the amount that was calculated to potentially evaporate.		If, during any timestep, the amount of water present is less than what is calculated to evaporate, the water present will evaporate, but because there was not enough water to evaporate, the actual total amount of evaporation will be less than the amount that was calculated to potentially evaporate.

			{{article end
			\|seealso=
			* [[Ground transpiration result type (Water Overlay)]]
			* [[Surface evaporation result type (Water Overlay)]]
			* [[Evapotranspiration result type (Water Overlay)]]
	==Related formulas==		==Related formulas==
	* [[Surface evaporation formula (Water Overlay)\|Surface evaporation formula]]		* [[Surface evaporation formula (Water Overlay)\|Surface evaporation formula]]
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	* [[Ground model (Water Overlay)\|Ground model]]		* [[Ground model (Water Overlay)\|Ground model]]

	~~{{article end~~
	~~\|seealso=~~
	* [[Ground transpiration result type (Water Overlay)]]
	* [[Surface evaporation result type (Water Overlay)]]
	* [[Evapotranspiration result type (Water Overlay)]]
	\|notes=		\|notes=
	* The [[Water Overlay Wizard\|configuration wizard]] is the easiest way to adjust evaporation and rainfall.		* The [[Water Overlay Wizard\|configuration wizard]] is the easiest way to adjust evaporation and rainfall.

Frank@tygron.nl at 10:45, 16 December 2025

2025-12-16T10:45:41Z

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 If, during any timestep, the amount of water present is less than what is calculated to evaporate, the water present will evaporate, but because there was not enough water to evaporate, the actual total amount of evaporation will be less than the amount that was calculated to potentially evaporate.
 {{article end
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 * If the next time key for the evaporation rate is smaller than the previous time key for [[rain model (Water Overlay)|rainfall]], the previous rate of evaporation is continued until the end of the simulation.
 }}
 {{WaterOverlay formula nav}}

Frank@tygron.nl at 10:45, 16 December 2025

2025-12-16T10:45:14Z

← Older revision		Revision as of 10:45, 16 December 2025
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	{{article end		{{article end
			\|seealso=
			* [[Ground transpiration result type (Water Overlay)]]
			* [[Surface evaporation result type (Water Overlay)]]
			* [[Evapotranspiration result type (Water Overlay)]]
	\|notes=		\|notes=
	* The [[Water Overlay Wizard\|configuration wizard]] is the easiest way to adjust evaporation and rainfall.		* The [[Water Overlay Wizard\|configuration wizard]] is the easiest way to adjust evaporation and rainfall.

Maxim@tygron.com at 14:16, 22 July 2025

2025-07-22T14:16:39Z

← Older revision		Revision as of 14:16, 22 July 2025
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	=== Feddes factor ===		=== Feddes factor ===
	Conceptually, water can ~~evaporate~~ from the ground via crop, tree and plant foliage. Their roots can draw water from the unsaturated and saturated zones in the ground, when these reach deep enough and the [[Water ~~evaporation~~ factor (Water Overlay)\|~~evaporation~~ factor]] is non-zero. Water is drawn from the ground and ~~evaporated~~ into the air, effectively removing it from the hydrological model.		Conceptually, water can transpirate from the ground via crop, tree and plant foliage. Their roots can draw water from the unsaturated and saturated zones in the ground, when these reach deep enough and the [[Water transpiration factor (Water Overlay)\|transpiration factor]] is non-zero. Water is drawn from the ground and transpirated into the air, effectively removing it from the hydrological model.
	Water for ~~evaporation~~ can only be drawn from sections of the ground which are within reach of the roots, as defined by the root depth. Using the multiple root depth values, it is also possible to define a threshold at which the roots are unable, or less able, to extract ground water, due to oxygen stress. It such case up to 4 root depth values have to be provided, from deepest to less deep.		Water for transpiration can only be drawn from sections of the ground which are within reach of the roots, as defined by the root depth. Using the multiple root depth values, it is also possible to define a threshold at which the roots are unable, or less able, to extract ground water, due to oxygen stress. It such case up to 4 root depth values have to be provided, from deepest to less deep.

	[[File:Feddes_trapezium.jpg\|500px]]		[[File:Feddes_trapezium.jpg\|500px]]
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	=== Seasonal factor ===		=== Seasonal factor ===
	[[File:Seasonal_evap_grass.jpg\|thumb\|right\|Varying [[Water evaporation factor (Water Overlay)\|evaporation factor]] of grass, depending on the [[Season formula (Water Overlay)\|time of year]].]]		[[File:Seasonal_evap_grass.jpg\|thumb\|right\|Varying [[Water evaporation factor (Water Overlay)\|evaporation factor]] of grass, depending on the [[Season formula (Water Overlay)\|time of year]].]]
	The ground evaporation can be configured directly by changing the terrain type's [[terrain water ~~evaporation~~ factor (Water Overlay)\|~~WATER_EVAPORATION_FACTOR~~]] and building 's [[Water evaporation factor (Water Overlay)\|~~WATER_EVAPORATION_FACTOR~~]]. If these attributes are set to 0, no ground evaporation will take place. This attribute can also be set as 4 distinct values, one for each [[Season formula (Water Overlay)\|growth season]]. This allows for more ~~evaporation~~ during a crops growth season and less during the winter.		The ground evaporation can be configured directly by changing the terrain type's [[terrain water transpiration factor (Water Overlay)\|WATER_TRANSPIRATION_FACTOR]] and building 's [[Water evaporation factor (Water Overlay)\|WATER_TRANSPIRATION_FACTOR]]. If these attributes are set to 0, no ground evaporation will take place. This attribute can also be set as 4 distinct values, one for each [[Season formula (Water Overlay)\|growth season]]. This allows for more transpiration during a crops growth season and less during the winter.

	=== Varying ~~evaporation~~ rate===		=== Varying transpiration rate===
	Similar to the [[#Surface evaporation\|surface evaporation]], the rate of ground ~~evaporation~~ is also determined by the [[Weather (Water Overlay)\|weather definition]]'s [[Evaporation m (Water Overlay)\|evaporation rate]]. Multiplying the weather's evaporation rate and the ~~evaporation~~ factor of the building or terrain (as applicable) gives the actual ~~evaporation~~ rate for the ground.		Similar to the [[#Surface evaporation\|surface evaporation]], the rate of ground transpiration is also determined by the [[Weather (Water Overlay)\|weather definition]]'s [[Evaporation m (Water Overlay)\|evaporation rate]]. Multiplying the weather's evaporation rate and the transpiration factor of the building or terrain (as applicable) gives the actual transpiration rate for the ground.

	Ground ~~evaporation~~ first draws water from the unsaturated region and then from the saturated region. If, according to the calculated ~~evaporation~~ rate, a sufficient amount of water can ~~evaporate~~ from the unsaturated zone, no water will ~~evaporate~~ from the saturated zone. Otherwise, all water in the unsaturated zone which is in reach of the roots of the building or terrain (as applicable) is ~~evaporated~~, and the remainder of the amount of water which should ~~evaporate~~ according to the ~~evaporation~~ rate is ~~evaporated~~ from the saturated zone. The sum of ~~evaporation~~ in the unsaturated zone and the saturated zone will never exceed the calculated ~~evaporation~~ rate.		Ground transpiration first draws water from the unsaturated region and then from the saturated region. If, according to the calculated transpiration rate, a sufficient amount of water can transpirate from the unsaturated zone, no water will transpirate from the saturated zone. Otherwise, all water in the unsaturated zone which is in reach of the roots of the building or terrain (as applicable) is transpirated, and the remainder of the amount of water which should transpirate according to the transpiration rate is transpirated from the saturated zone. The sum of transpiration in the unsaturated zone and the saturated zone will never exceed the calculated transpiration rate.

	==Example for dynamic evaporation==		==Example for dynamic evaporation==
	See the table below for an example of dynamic ~~evaporation~~:		See the table below for an example of dynamic transpiration:
	{\| class="wikitable"		{\| class="wikitable"
	!Time key (minutes)		!Time key (minutes)

Maxim@tygron.com at 14:07, 22 July 2025

2025-07-22T14:07:32Z

← Older revision		Revision as of 14:07, 22 July 2025
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	Water can transpire from the [[Ground model (Water Overlay)\|ground]] if the cell's surface meets either of the following criteria:		Water can transpire from the [[Ground model (Water Overlay)\|ground]] if the cell's surface meets either of the following criteria:
	* A [[building]] on the surface		* A [[building]] on the surface
	** The building has a non-zero [[Water ~~evaporation~~ factor (Water Overlay)\|~~WATER_EVAPORATION_FACTOR~~]].		** The building has a non-zero [[Water transpiration factor (Water Overlay)\|WATER_TRANSPIRATION_FACTOR]].
	** The building has a non-zero [[Root depth m (Water Overlay)\|root depths]].		** The building has a non-zero [[Root depth m (Water Overlay)\|root depths]].
	* No building on the surface		* No building on the surface
	** The surface terrain type has a non-zero [[terrain water ~~evaporation~~ factor (Water Overlay)\|~~WATER_EVAPORATION_FACTOR~~]].		** The surface terrain type has a non-zero [[terrain water transpiration factor (Water Overlay)\|WATER_TRANSPIRATION_FACTOR]].
	** The surface terrain type has a non-zero [[terrain root depth m (Water Overlay)\|root depths]].		** The surface terrain type has a non-zero [[terrain root depth m (Water Overlay)\|root depths]].
	In other words: if a building is present the building's properties are used, otherwise the terrain's properties are used.		In other words: if a building is present the building's properties are used, otherwise the terrain's properties are used.
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	==Related formulas==		==Related formulas==
	* [[Surface evaporation formula (Water Overlay)\|Surface evaporation formula]]		* [[Surface evaporation formula (Water Overlay)\|Surface evaporation formula]]
	* [[Ground ~~evaporation~~ formula (Water Overlay)\|Ground ~~evaporation~~ formula]]		* [[Ground transpiration formula (Water Overlay)\|Ground transpiration formula]]

	==Related models==		==Related models==

Maxim@tygron.com at 13:33, 16 July 2025

2025-07-16T13:33:40Z

← Older revision		Revision as of 13:33, 16 July 2025
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	The default setup for evaporation consists of a single period of evaporation and an evaporation amount. It is possible to configure an evaporation rate which [[How_to_load_in_dynamic_evaporation_rate_(Water_Overlay)\|varies over time]]. More periods with varying amounts of evaporation (including an evaporation rate of zero) can be defined.		The default setup for evaporation consists of a single period of evaporation and an evaporation amount. It is possible to configure an evaporation rate which [[How_to_load_in_dynamic_evaporation_rate_(Water_Overlay)\|varies over time]]. More periods with varying amounts of evaporation (including an evaporation rate of zero) can be defined.

	[[File:Evapotranspiration.jpg\|~~small\|No description.~~]]		[[File:Evapotranspiration.jpg\|500px]]

	==Surface Evaporation==		==Surface Evaporation==

Maxim@tygron.com at 13:33, 16 July 2025

2025-07-16T13:33:11Z

← Older revision		Revision as of 13:33, 16 July 2025
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	The default setup for evaporation consists of a single period of evaporation and an evaporation amount. It is possible to configure an evaporation rate which [[How_to_load_in_dynamic_evaporation_rate_(Water_Overlay)\|varies over time]]. More periods with varying amounts of evaporation (including an evaporation rate of zero) can be defined.		The default setup for evaporation consists of a single period of evaporation and an evaporation amount. It is possible to configure an evaporation rate which [[How_to_load_in_dynamic_evaporation_rate_(Water_Overlay)\|varies over time]]. More periods with varying amounts of evaporation (including an evaporation rate of zero) can be defined.

	[[File:Evapotranspiration.jpg\|No description.]]		[[File:Evapotranspiration.jpg\|small\|No description.]]

	==Surface Evaporation==		==Surface Evaporation==

Maxim@tygron.com at 13:32, 16 July 2025

2025-07-16T13:32:42Z

← Older revision		Revision as of 13:32, 16 July 2025
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	The default setup for evaporation consists of a single period of evaporation and an evaporation amount. It is possible to configure an evaporation rate which [[How_to_load_in_dynamic_evaporation_rate_(Water_Overlay)\|varies over time]]. More periods with varying amounts of evaporation (including an evaporation rate of zero) can be defined.		The default setup for evaporation consists of a single period of evaporation and an evaporation amount. It is possible to configure an evaporation rate which [[How_to_load_in_dynamic_evaporation_rate_(Water_Overlay)\|varies over time]]. More periods with varying amounts of evaporation (including an evaporation rate of zero) can be defined.

	[[File:Evapotranspiration.jpg~~\|thumb~~\|No description.]]		[[File:Evapotranspiration.jpg\|No description.]]

	==Surface Evaporation==		==Surface Evaporation==