OR/14/007 Modules - Revision history

Ajhil: /* VKD */

2021-10-20T08:51:24Z

VKD

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	[[Image:14007 math13.png\|frameless\|center\| 500px\| ]]		[[Image:14007 math13.png\|frameless\|center\| 500px\| ]]
	{{clear}}[[Image:14007 fig3.7.png\|thumb\|center\|300px\|'''Figure 3.7'''    VKD saturated zone component.]]{{clear}}		{{clear}}[[Image:14007 fig3.7.png\|thumb\|center\|300px\|'''Figure 3.7'''    VKD saturated zone component.]]{{clear}}

	~~Hydraulic conductivity~~

	==Reference==		==Reference==

	[[Category:OR/14/007_AquiMod User Manual (v1.0)\| 03]]		[[Category:OR/14/007_AquiMod User Manual (v1.0)\| 03]]

Ajhil: /* Q1T1S1 */

2021-10-20T08:50:41Z

Q1T1S1

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	Like the Q1K1S1 saturated zone component, this component also employs a single outlet (Figure 3.6). However, the transmissivity is assumed to be fixed and independent of the hydraulic head, h. This is equivalent to a confined aquifer representation.		Like the Q1K1S1 saturated zone component, this component also employs a single outlet (Figure 3.6). However, the transmissivity is assumed to be fixed and independent of the hydraulic head, h. This is equivalent to a confined aquifer representation.
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	[[Image:14007 fig3.6.png\|thumb\|center\|300px\| '''Figure 3.6''' Q1T1S1 saturated zone component.]]		[[Image:14007 fig3.6.png\|thumb\|center\|300px\| '''Figure 3.6'''    Q1T1S1 saturated zone component.]]
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Ajhil: /* 3.3.5 VKD */

2021-10-20T08:50:27Z

3.3.5 VKD

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	==~~3.3.5~~ VKD==		===VKD===
	As an alternative to using specified layers and outlets, the user can also implement a variable conductivity with depth (VKD) profile. Here a ‘cocktail glass’ representation is can be employed which has two distinct sections (Figure 3.7). In the lower section, between the base of the aquifer, z1 and the elevation of the point of inflection, zp, the hydraulic conductivity is constant. In the upper section above zp, the hydraulic conductivity increases linearly with elevation. Subsequently, the transmissivity is calculated as:		As an alternative to using specified layers and outlets, the user can also implement a variable conductivity with depth (VKD) profile. Here a ‘cocktail glass’ representation is can be employed which has two distinct sections (Figure 3.7). In the lower section, between the base of the aquifer, z1 and the elevation of the point of inflection, zp, the hydraulic conductivity is constant. In the upper section above zp, the hydraulic conductivity increases linearly with elevation. Subsequently, the transmissivity is calculated as:

Ajhil: /* Q3K3S1= */

2021-10-20T08:49:50Z

Q3K3S1=

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	</center>		</center>

	==Q3K3S1===		===Q3K3S1===
	This component represents flow in the saturated zone by a rectangular block of aquifer with dimensions ∆x and ∆y denoting its length and width [L] respectively. A mass balance calculation is performed at each time-step to calculate the new groundwater head:		This component represents flow in the saturated zone by a rectangular block of aquifer with dimensions ∆x and ∆y denoting its length and width [L] respectively. A mass balance calculation is performed at each time-step to calculate the new groundwater head:

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	[[Image:14007 fig3.6.png\|thumb\|center\|300px\| '''Figure 3.6''' Q1T1S1 saturated zone component.]]		[[Image:14007 fig3.6.png\|thumb\|center\|300px\| '''Figure 3.6''' Q1T1S1 saturated zone component.]]
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	==3.3.5 VKD==		==3.3.5 VKD==
	As an alternative to using specified layers and outlets, the user can also implement a variable conductivity with depth (VKD) profile. Here a ‘cocktail glass’ representation is can be employed which has two distinct sections (Figure 3.7). In the lower section, between the base of the aquifer, z1 and the elevation of the point of inflection, zp, the hydraulic conductivity is constant. In the upper section above zp, the hydraulic conductivity increases linearly with elevation. Subsequently, the transmissivity is calculated as:		As an alternative to using specified layers and outlets, the user can also implement a variable conductivity with depth (VKD) profile. Here a ‘cocktail glass’ representation is can be employed which has two distinct sections (Figure 3.7). In the lower section, between the base of the aquifer, z1 and the elevation of the point of inflection, zp, the hydraulic conductivity is constant. In the upper section above zp, the hydraulic conductivity increases linearly with elevation. Subsequently, the transmissivity is calculated as:

Ajhil: /* Weibull */

2021-10-20T08:49:19Z

Weibull

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	[[Image:14007 fig3.2.png\|thumb\|center\|~~300px~~\| '''Figure 3.2'''    Probability distribution function of the Weibull distribution using different λ and k combinations.]]		[[Image:14007 fig3.2.png\|thumb\|center\|500px\| '''Figure 3.2'''    Probability distribution function of the Weibull distribution using different λ and k combinations.]]
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Ajhil: /* Weibull */

2021-10-20T08:49:03Z

Weibull

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	where α is the scaling parameter. The Weibull function can represent exponentially increasing, exponentially decreasing, and positively and negatively skewed distributions. It is used because it allows the exploration of different distributions, whilst being smooth, which is considered to be more physically justifiable than randomly selected monthly weights.		where α is the scaling parameter. The Weibull function can represent exponentially increasing, exponentially decreasing, and positively and negatively skewed distributions. It is used because it allows the exploration of different distributions, whilst being smooth, which is considered to be more physically justifiable than randomly selected monthly weights.
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	[[Image:14007 fig3.2.png\|thumb\|center\|300px\| '''Figure 3.2''' Probability distribution function of the Weibull distribution using different λ and k combinations.]]
			[[Image:14007 fig3.2.png\|thumb\|center\|300px\| '''Figure 3.2'''    Probability distribution function of the Weibull distribution using different λ and k combinations.]]
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Ajhil: /* Unsaturated Zone Module */

2021-10-20T08:48:36Z

Unsaturated Zone Module

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	{\| class="wikitable"		{\| class="wikitable"
	\|+ Table 3.2    Summary of unsaturated zone module components.		\|+ Table 3.2    Summary of unsaturated zone module components.
	! ID !! Name !! ~~description~~		! '''ID''' !! '''Name''' !! '''Description'''
	\|-		\|-
	\| 1 \|\| Weibull \|\| Drainage from the soil is attenuated through the unsaturated zone using a Weibull distribution transfer function.		\| 1 \|\| Weibull \|\| Drainage from the soil is attenuated through the unsaturated zone using a Weibull distribution transfer function.

Ajhil: /* FAO */

2021-10-20T08:48:04Z

FAO

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	[[Image:14007 fig3.1.png\|thumb\|center\|~~300px~~\|'''Figure 3.1 (a)''' FAO soil zone component conceptualised as a bucket with a finite capacity and (b) the change in ratio of AET to PET with SMD as described by equation 4.]]		[[Image:14007 fig3.1.png\|thumb\|center\|500px\|'''Figure 3.1 (a)'''    FAO soil zone component conceptualised as a bucket with a finite capacity and (b) the change in ratio of AET to PET with SMD as described by equation 4.]]
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Ajhil: /* Soil Zone Module */

2021-10-20T08:47:22Z

Soil Zone Module

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	{\| class="wikitable"		{\| class="wikitable"
	\|+ Table 2    Summary of soil zone module components.		\|+ Table 2    Summary of soil zone module components.
	\| '''ID \|\| Name \|\| Description'''		\| '''ID''' \|\| '''Name''' \|\| '''Description'''
	\|-		\|-
	\| 1 \|\| FAO \|\| Drainage from the base of the soil zone is calculated using a soil water balance method based on a simplification of the algorithm developed by the UN Food and Agricultural Organisation (Allen et al., 1998<ref name="Allen">Allen, R G, Pereira, L S, Raes, D & Smith, M. 1998. Crop evapotranspiration — Guidelines for computing crop water requirements — FAO Irrigation and drainage paper 56. Food and Agriculture Organization of the United Nations. </ref>).		\| 1 \|\| FAO \|\| Drainage from the base of the soil zone is calculated using a soil water balance method based on a simplification of the algorithm developed by the UN Food and Agricultural Organisation (Allen et al., 1998<ref name="Allen">Allen, R G, Pereira, L S, Raes, D & Smith, M. 1998. Crop evapotranspiration — Guidelines for computing crop water requirements — FAO Irrigation and drainage paper 56. Food and Agriculture Organization of the United Nations. </ref>).

Ajhil at 08:46, 20 October 2021

2021-10-20T08:46:57Z

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	</center>		</center>

	==~~3.1.1~~ FAO==		===FAO===
	This component simulates soil moisture as a function of vegetation and soil properties. The soil column is conceptualised as a bucket with a maximum volume of water available to plants after the soil has drained to its field capacity (Figure 3.1a). This is termed the ''total available water ''(TAW) which is calculated as:		This component simulates soil moisture as a function of vegetation and soil properties. The soil column is conceptualised as a bucket with a maximum volume of water available to plants after the soil has drained to its field capacity (Figure 3.1a). This is termed the ''total available water ''(TAW) which is calculated as:

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	where SMD is the ''soil moisture deficit ''[L], PPTN is the total ''precipitation ''input [L] and AET is the ''actual evapotranspiration ''[L], which is calculated as a function of ''potential evapotranspiration ''(PET) [L] and the SMD (Figure 3.1b):		where SMD is the ''soil moisture deficit ''[L], PPTN is the total ''precipitation ''input [L] and AET is the ''actual evapotranspiration ''[L], which is calculated as a function of ''potential evapotranspiration ''(PET) [L] and the SMD (Figure 3.1b):


	[[Image:14007 math4.png\|frameless\|center\| 500px\| ]]		[[Image:14007 math4.png\|frameless\|center\| 500px\| ]]


	When the soil zone becomes saturated any rainfall in excess of the evaporative demand of the vegetation becomes ''excess water ''(EXW). This excess water is then split between soil drainage and ''surface runoff''. The proportion of the excess water (EXW) that drains to the unsaturated zone is:		When the soil zone becomes saturated any rainfall in excess of the evaporative demand of the vegetation becomes ''excess water ''(EXW). This excess water is then split between soil drainage and ''surface runoff''. The proportion of the excess water (EXW) that drains to the unsaturated zone is:
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	where SD is the soil drainage and BFI is the ''baseflow index'', which defines the average proportion of stream flow that a river receives from groundwater discharge. Surface runoff is then calculated as the remainder of the excess water.		where SD is the soil drainage and BFI is the ''baseflow index'', which defines the average proportion of stream flow that a river receives from groundwater discharge. Surface runoff is then calculated as the remainder of the excess water.
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	[[Image:14007 fig3.1.png\|thumb\|center\|300px\|'''Figure 3.1 (a)''' FAO soil zone component conceptualised as a bucket with a finite capacity and (b) the change in ratio of AET to PET with SMD as described by equation 4.]]		[[Image:14007 fig3.1.png\|thumb\|center\|300px\|'''Figure 3.1 (a)''' FAO soil zone component conceptualised as a bucket with a finite capacity and (b) the change in ratio of AET to PET with SMD as described by equation 4.]]
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	==Unsaturated Zone Module ==		==Unsaturated Zone Module==

	Currently there is only one unsaturated zone component available in the AquiMod software (Table 3.2).		Currently there is only one unsaturated zone component available in the AquiMod software (Table 3.2).
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	</center>		</center>

	===~~3.2.1~~ Weibull===		===Weibull===
	Recharge is distributed over a number of time-steps, n, and the proportion of soil drainage for each time-step is calculated using a two-parameter Weibull probability density function:		Recharge is distributed over a number of time-steps, n, and the proportion of soil drainage for each time-step is calculated using a two-parameter Weibull probability density function:

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	</center>		</center>

	==~~3.3.1~~ Q3K3S1==		==Q3K3S1===
	This component represents flow in the saturated zone by a rectangular block of aquifer with dimensions ∆x and ∆y denoting its length and width [L] respectively. A mass balance calculation is performed at each time-step to calculate the new groundwater head:		This component represents flow in the saturated zone by a rectangular block of aquifer with dimensions ∆x and ∆y denoting its length and width [L] respectively. A mass balance calculation is performed at each time-step to calculate the new groundwater head:

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	where i is the layer number for m layers and ∆h<sub>i</sub> [L] is the difference between the groundwater head and the elevation of the aquifer outlet point. Importantly due to the explicit form of Equation 9 used, the groundwater head at the previous time-step, h* [L] is used:		where i is the layer number for m layers and ∆h<sub>i</sub> [L] is the difference between the groundwater head and the elevation of the aquifer outlet point. Importantly due to the explicit form of Equation 9 used, the groundwater head at the previous time-step, h* [L] is used:


	[[Image:14007 math10.png\|frameless\|center\| 500px\| ]]		[[Image:14007 math10.png\|frameless\|center\| 500px\| ]]
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	Using this component, the hydraulic conductivity can be configured to increase or decrease with depth according to the user’s preference. However, for some aquifers it may be preferable to have an increasing hydraulic conductivity with elevation. As such, an additional α parameter also exists for this component which can be switched to force this condition when using randomly sampled Monte Carlo parameter sets (See Appendix 1).		Using this component, the hydraulic conductivity can be configured to increase or decrease with depth according to the user’s preference. However, for some aquifers it may be preferable to have an increasing hydraulic conductivity with elevation. As such, an additional α parameter also exists for this component which can be switched to force this condition when using randomly sampled Monte Carlo parameter sets (See Appendix 1).
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	[[Image:14007 fig3.3.png\|thumb\|center\| 300px\| '''Figure 3.3''' Q3K3S1 saturated zone component.]]		[[Image:14007 fig3.3.png\|thumb\|center\| 300px\| '''Figure 3.3'''    Q3K3S1 saturated zone component.]]
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	==~~3.3.2~~ Q2K2S1==		===Q2K2S1===
	This component employs the same structure according to equations 8-11, however, here only two layers are defined. Each layer is independent and has its own discharge outlet (Figure 3.4). The deepest layer represents groundwater which flows out of the catchment via subsurface flow paths. The upper outlet is a lumped representation of surface discharge points in the catchment including rivers and springs. It may flow intermittently if the groundwater head falls below the outlet elevation. As with the Q3K3S1 component, the hydraulic conductivity can be forced to increase with elevation when using randomly sampled parameter sets by specifying the α parameter.		This component employs the same structure according to equations 8-11, however, here only two layers are defined. Each layer is independent and has its own discharge outlet (Figure 3.4). The deepest layer represents groundwater which flows out of the catchment via subsurface flow paths. The upper outlet is a lumped representation of surface discharge points in the catchment including rivers and springs. It may flow intermittently if the groundwater head falls below the outlet elevation. As with the Q3K3S1 component, the hydraulic conductivity can be forced to increase with elevation when using randomly sampled parameter sets by specifying the α parameter.
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	==~~3.3.3~~ Q1K1S1==		=== Q1K1S1===
	This component employs the same structure according to equations 8-11, however, here only one layer is defined with a single discharge outlet (Figure 3.5).		This component employs the same structure according to equations 8-11, however, here only one layer is defined with a single discharge outlet (Figure 3.5).
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	[[Image:14007 fig3.5.png\|thumb\|center\|300px\| '''Figure 3.5''' Q1K1S1 saturated zone component.]]		[[Image:14007 fig3.5.png\|thumb\|center\|300px\| '''Figure 3.5'''    Q1K1S1 saturated zone component.]]
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	==~~3.3.4~~ Q1T1S1==
			===Q1T1S1===
	Like the Q1K1S1 saturated zone component, this component also employs a single outlet (Figure 3.6). However, the transmissivity is assumed to be fixed and independent of the hydraulic head, h. This is equivalent to a confined aquifer representation.		Like the Q1K1S1 saturated zone component, this component also employs a single outlet (Figure 3.6). However, the transmissivity is assumed to be fixed and independent of the hydraulic head, h. This is equivalent to a confined aquifer representation.
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	[[Image:14007 math13.png\|frameless\|center\| 500px\| ]]		[[Image:14007 math13.png\|frameless\|center\| 500px\| ]]
	{{clear}}[[Image:14007 fig3.7.png\|thumb\|center\|300px\|'''Figure 3.7''' VKD saturated zone component.]]{{clear}}		{{clear}}[[Image:14007 fig3.7.png\|thumb\|center\|300px\|'''Figure 3.7'''    VKD saturated zone component.]]{{clear}}

	Hydraulic conductivity		Hydraulic conductivity