Wetlands - Revision history

Peni Metho: /* Interactions controlling the wetland’s access to water */

2021-06-08T08:11:53Z

Interactions controlling the wetland’s access to water

Peni Metho at 14:23, 7 June 2021

2021-06-07T14:23:48Z

Peni Metho at 14:20, 7 June 2021

2021-06-07T14:20:26Z

Peni Metho at 14:19, 7 June 2021

2021-06-07T14:19:48Z

Peni Metho at 14:17, 7 June 2021

2021-06-07T14:17:06Z

Peni Metho at 13:52, 7 June 2021

2021-06-07T13:52:13Z

Peni Metho at 13:38, 7 June 2021

2021-06-07T13:38:21Z

Peni Metho: /* Wetland storage and water balance concept */

2021-06-07T13:33:30Z

Wetland storage and water balance concept

Peni Metho at 13:28, 7 June 2021

2021-06-07T13:28:37Z

Peni Metho at 13:17, 7 June 2021

2021-06-07T13:17:42Z

@@ Line 151: / Line 151: @@
 |}
-<sup><small>a</small></sup> <small>ACRU4 has a riparian zone HRU which can be used as a wetland with direct subsurface and groundwater inflows; and bidirectional, horizontal groundwater interactions with the wetland storage '''(Julia's link to section on riparian zones)'''</small>
+<sup><small>a</small></sup> <small>ACRU4 has a riparian zone HRU which can be used as a wetland with direct subsurface and groundwater inflows; and bidirectional, horizontal groundwater interactions with the wetland storage '''('''''see'' riparian zones in [[applying tools in specific use cases]]''')'''</small>
 <sup><small>b</small></sup> <small>depends on wetland type: floodplains with subsurface storage will have bidirectional wetland-river interactions, floodplains with surface storage and lakes have unidirectional storage as water moves from the river into the wetland or from the wetland back into the river</small>

@@ Line 39: / Line 39: @@
 All modelling tools except for SWAT conceptualise its simulated wetland as riparian wetlands. In the case of SWAT, a riparian wetland can be modelled using modified versions of SWAT available from independent researchers.
-As another example of modifying setups to infer a wetland type, Rahman et al. (2016)<sup>3</sup> developed a version of SWAT with riparian wetlands by changing the internal mechanisms of the model to allow the wetland to receive water from the river as opposed to the wetland only contributing water to the river. A summary of the wetland type preferences is presented below.
+As another example of modifying setups to infer a wetland type, Rahman et al. (2016)<sup>[https://doi.org/10.1016/j.envsoft.2016.07.003 5]</sup> developed a version of SWAT with riparian wetlands by changing the internal mechanisms of the model to allow the wetland to receive water from the river as opposed to the wetland only contributing water to the river. A summary of the wetland type preferences is presented below.
 {| class="wikitable"
 |+Type of wetlands in modelling tools
@@ Line 174: / Line 174: @@
 '''<small>[4]</small>''' <small>Rivers-Moore, N. A., Kotze, D. C., Job, N., & Mohanlal, S. (2020). Prediction of Wetland Hydrogeomorphic Type Using Morphometrics and Landscape Characteristics. Frontiers in Environmental Science, 8, 58. https://doi.org/10.3389/fenvs.2020.00058</small>
-<small>'''[5]'''</small> <small>Rahman, M. M., Thompson, J. R., & Flower, R. J. (2016). An enhanced SWAT wetland module to quantify hydraulic interactions between riparian depressional wetlands, rivers and aquifers. Environmental Modelling & Software, 84, 263-289. DOI: 10.1016/j.envsoft.2016.07.003.</small>
+<small>'''[5]'''</small> <small>Rahman, M. M., Thompson, J. R., & Flower, R. J. (2016). An enhanced SWAT wetland module to quantify hydraulic interactions between riparian depressional wetlands, rivers and aquifers. Environmental Modelling & Software, 84, 263-289. https://doi.org/10.1016/j.envsoft.2016.07.003.</small>
 <small>'''[6]'''</small> <small>Gray, R.P. (2011). Techniques for Assessing the Impacts of Wetlands on Hydrological Responses Under Varying Climatic Conditions. (Master's dissertation, Pietermaritzburg: University of KwaZulu-Natal). http://hdl.handle.net/10413/8076</small>
 <small>'''[7]'''</small> <small>Yeo, I. Y., Lee, S., Lang, M. W., Yetemen, O., McCarty, G. W., Sadeghi, A. M., & Evenson, G. (2019). Mapping landscape-level hydrological connectivity of headwater wetlands to downstream waters: A catchment modelling approach-Part 2. Science of the Total Environment, 653, 1557-1570. https://doi.org/10.1016/j.scitotenv.2018.11.237</small>

← Older revision		Revision as of 14:20, 7 June 2021
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	Using the national classification system of wetlands and other aquatic ecosystems in South Africa endorsed by SANBI (Ollis et al., 2013)<sup>[http://biodiversityadvisor.sanbi.org/wp-content/uploads/2016/07/Classification-system-for-wetlands-other-aquatic-ecosystems.pdf]</sup>, information about the physical wetland’s characteristics, hydrological processes and water movement, as well as its regulatory role on streamflow is available. The fourth level classification of wetlands as hydrogeomorphic units provides this information and has been used in other hydrological studies (Maherry et al., 2017<sup>[http://www.wrc.org.za/wp-content/uploads/mdocs/2191-1-16.pdf 2]</sup>; Tanner et al., 2019<sup>[http://www.wrc.org.za/wp-content/uploads/mdocs/2548_final.pdf 3]</sup>, Rivers-Moore et al., 2020<sup>[https://doi.org/10.3389/fenvs.2020.00058 4]</sup>).		Using the national classification system of wetlands and other aquatic ecosystems in South Africa endorsed by SANBI (Ollis et al., 2013)<sup>[http://biodiversityadvisor.sanbi.org/wp-content/uploads/2016/07/Classification-system-for-wetlands-other-aquatic-ecosystems.pdf]</sup>, information about the physical wetland’s characteristics, hydrological processes and water movement, as well as its regulatory role on streamflow is available. The fourth level classification of wetlands as hydrogeomorphic units provides this information and has been used in other hydrological studies (Maherry et al., 2017<sup>[http://www.wrc.org.za/wp-content/uploads/mdocs/2191-1-16.pdf 2]</sup>; Tanner et al., 2019<sup>[http://www.wrc.org.za/wp-content/uploads/mdocs/2548_final.pdf 3]</sup>, Rivers-Moore et al., 2020<sup>[https://doi.org/10.3389/fenvs.2020.00058 4]</sup>).

−	This information serves as a standard and comparable starting point for describing the physical wetland. If the situation allows, this information can be supplemented with ~~information~~ from local monitoring.	+	This information serves as a standard and comparable starting point for describing the physical wetland. If the situation allows, this information can be supplemented with data from local monitoring.

@@ Line 162: / Line 162: @@
 == References==
-<small>This page presents material adapted from Metho, 2021, A case study approach comparing wetland representation in hydrological models when estimating water availability for long-term averages, and short-term floods and droughts, MSc dissertation, UCT, supported (in-part) by the WRC project “Critical catchment model inter-comparison and model use guidance development” (2019-2021) '''(add link to project background page)'''</small>
+<small>This page presents material adapted from Metho, 2021, "A case study approach comparing wetland representation in hydrological models when estimating water availability for long-term averages, and short-term floods and droughts" MSc dissertation, UCT, supported (in-part) by the WRC project “Critical catchment model inter-comparison and model use guidance development” (2019-2021) '''(''see'' [[Model inter-comparison study (2020-21)]])'''</small>
 <small>Citations</small>

@@ Line 31: / Line 31: @@
-Each modelling tool can explicitly represent one type of wetland. A summary of the wetland type preferences is presented in Table 1.
+Each modelling tool can explicitly represent one type of wetland. In some modelling tools, the alternative wetland type can be implied by modifying the setup of the wetland unit in the catchment and how water is routed through the catchment.
 For example, a simulated wetland in ACRU-4 was designed to represent riparian wetlands. However, GIWs can be represented by splitting one catchment into two subcatchments, with the upland subcatchment containing riparian wetlands to act as GIWs (Gray, 2011)<sup>[http://hdl.handle.net/10413/8076 6]</sup>.
@@ Line 41: / Line 39: @@
 All modelling tools except for SWAT conceptualise its simulated wetland as riparian wetlands. In the case of SWAT, a riparian wetland can be modelled using modified versions of SWAT available from independent researchers.
-As another example of modifying setups to infer a wetland type, Rahman et al. (2016)<sup>3</sup> developed a version of SWAT with riparian wetlands by changing the internal mechanisms of the model to allow the wetland to receive water from the river as opposed to the wetland only contributing water to the river.
+As another example of modifying setups to infer a wetland type, Rahman et al. (2016)<sup>3</sup> developed a version of SWAT with riparian wetlands by changing the internal mechanisms of the model to allow the wetland to receive water from the river as opposed to the wetland only contributing water to the river. A summary of the wetland type preferences is presented below.
 {| class="wikitable"
-|+Table 1. Type of wetlands in modelling tools
+|+Type of wetlands in modelling tools
 !Description!! style="background:#F2CEE0;" |WRSM-Pitman!! style="background:#F2D4CE;" |SPATSIM-Pitman!! style="background:#CEF2CE;" |ACRU-4!! style="background:#F2F2CE;" |SWAT!! style="background:#CEE6F2;" |MIKE-SHE
 |-
@@ Line 58: / Line 52: @@
 !Ability to infer counter wetland type
 | style="background:#FFF5FA;" |Yes|| style="background:#FFF7F5;" | Yes|| style="background:#F5FFF5;" |No|| style="background:#FFFFF5;" |No|| style="background:#F5F8FF;" |Yes
 |}
 ==Wetland storage and water balance concept==
 There are two components to the wetland water balance concept: the storage and regulation of the storage with inflows and outflows.
@@ Line 68: / Line 67: @@
 *the processes regulating the wetland storage (the mechanism for how the wetland is filled with and releases water, sometimes referred to as the spill-and-fill process)
 * the spatiotemporal scale of the simulated wetland and storage calculations (the spatial scale of the wetland, its catchment unit in the context of the modelling tool and the rate or time step at which water levels are calculated)
+The following table describes these wetland storage differences in the modelling tools compared.
 {| class="wikitable"
-|+Table 2. Wetland storage characteristics, processes and scale
+|+Wetland storage characteristics, processes and scale
 !Description!! style="background:#F2CEE0;" |WRSM-Pitman!! style="background:#F2D4CE;" |SPATSIM-Pitman!! style="background:#CEF2CE;" |ACRU-4!! style="background:#F2F2CE;" |SWAT!! style="background:#CEE6F2;" |MIKE-SHE
 |-
@@ Line 86: / Line 85: @@
 |}
 The inflows and outflows of a simulated wetland water balance are indicators of the water sources available to the wetland and that the wetland can contribute to.
 An illustrative summary of the wetland water balances in each modelling tool is presented in '''Figure 1a-e'''. Most of the simulated wetlands receive surface water and rainfall as the main inflow with groundwater incorporated into the surface water flow pathway. ACRU and MIKE-SHE are the only tools with wetlands that have a separate inflow of groundwater. WRSM-Pitman and SWAT do not have direct groundwater outflows. In these tools, the wetlands contribution to groundwater is through baseflow and seepage losses, respectively. All modelling tools can account for water losses through evapotranspiration.
@@ Line 116: / Line 115: @@
 [[File:Water flow pathways between the wetland and the river or catchment.jpg|thumb|503x503px|Figure 2. Water flow pathways between the wetland and the river or catchment (Metho, 2021)]]
 Similar to the wetland water balance, the interactions that the simulated wetland has with the surrounding catchment and between different components of the catchment controls the wetlands access to water. The interactions are either unidirectional (going in one direction and downstream only) or bidirectional (able to go back and forth between the source and destination of the water). Figure 2 illustrates this in terms of water routing between wetland and surface water. Uni- and bidirectional flows are depicted on the left and right, respectively.
 The wetland’s interactions with groundwater can be uni- or bidirectional as well vertical and horizontal. Figure 3 illustrates the potential water flow pathways. Vertically, water can move up or downwards between the water stored, soil, subsurface materials and groundwater reserves. Horizontally, water can move between the wetland and the surrounding land. The dashed red lines indicate water moving bidirectionally from and to the wetland.
 [[File:Vertical and horizontal, uni- and bi-directional water flow pathways between the wetland and groudnwater.jpg|thumb|503x503px|Figure 3. Wetland-groundwater water flow pathways (Metho, 2021)]]
-Each modelling tool has a specific way of routing water to the river and uses the water flow pathways to capture the influence of the wetland on retaining and releasing water. The movement of water between water resources in the catchment and the wetland is presented in Table 3.
+Each modelling tool has a specific way of routing water to the river and uses the water flow pathways to capture the influence of the wetland on retaining and releasing water. The movement of water between water resources in the catchment and the wetland is tabulated in '''the main source of water and interactions of the wetland in the modelling tools'''.
 The inflows into the wetland may include surface water, groundwater or a combination of these sources. Some wetlands receive groundwater directly from subsurface water or from groundwater while other simulated wetlands receive groundwater as a proportion of runoff and river flows. Interactions between the wetland and the catchment, surface water, groundwater and river are possible. The difference between wetland-surface water interactions and wetland-river interactions is that the former represents the channel inflow component in the water balance and is at the upstream end of the wetland while the latter refers to the interactions between the wetland and the river of the (sub)catchment (this could be at the downstream or upstream end of the wetland). Water losses from the wetland to groundwater, the surrounding catchment and the channel, another important water loss is through evapotranspiration.
 {| class="wikitable"
-|+Table 3. The main source of water and interactions of the wetland in the modelling tools
+|+The main source of water and interactions of the wetland in the modelling tools
 !Description!! style="background:#F2CEE0;" |WRSM-Pitman!! style="background:#F2D4CE;" |SPATSIM-Pitman!! style="background:#CEF2CE;" | ACRU-4!! style="background:#F2F2CE;" |SWAT!! style="background:#CEE6F2;" |MIKE-SHE
 |-

@@ Line 21: / Line 21: @@
 ==Type of wetland==
-Simulated wetlands in modelling tools used in the model inter-comparison project '''(link to page listing models reviewed and the ICS page)''' have basic premises on which the wetland concept is built.
+Simulated wetlands in modelling tools used in the model inter-comparison project (''see'' [[Scope: what’s covered (and not!) in this wiki|Wiki scope: Modelling software tools & versions covered]] for a list of the modelling tools) have basic premises on which the wetland concept is built.
 *ACRU-4 conceptualises a simulated wetland as a depressional area with shallow water tables which become discharge zones for groundwater and surface water
@@ Line 114: / Line 114: @@
 ==Interactions controlling the wetland’s access to water ==
-[[File:Water flow pathways between the wetland and the river or catchment.jpg|thumb|503x503px|Figure x. Water flow pathways between the wetland and the river or catchment (Metho, 2021)]]
+[[File:Water flow pathways between the wetland and the river or catchment.jpg|thumb|503x503px|Figure 2. Water flow pathways between the wetland and the river or catchment (Metho, 2021)]]
-Similar to the wetland water balance, the interactions that the simulated wetland has with the surrounding catchment and between different components of the catchment controls the wetlands access to water. The interactions are either unidirectional (going in one direction and downstream only) or bidirectional (able to go back and forth between the source and destination of the water). Figure 3 illustrates this in terms of water routing between wetland and surface water. Uni- and bidirectional flows are depicted on the left and right, respectively.
+Similar to the wetland water balance, the interactions that the simulated wetland has with the surrounding catchment and between different components of the catchment controls the wetlands access to water. The interactions are either unidirectional (going in one direction and downstream only) or bidirectional (able to go back and forth between the source and destination of the water). Figure 2 illustrates this in terms of water routing between wetland and surface water. Uni- and bidirectional flows are depicted on the left and right, respectively.
-The movement of water between water resources in the catchment and the wetland is presented in Table 3. Each modelling tool has a specific way of routing water to the river and uses the water flow pathways to capture the influence of the wetland on retaining and releasing water.
+The wetland’s interactions with groundwater can be uni- or bidirectional as well vertical and horizontal. Figure 3 illustrates the potential water flow pathways. Vertically, water can move up or downwards between the water stored, soil, subsurface materials and groundwater reserves. Horizontally, water can move between the wetland and the surrounding land. The dashed red lines indicate water moving bidirectionally from and to the wetland.
 The inflows into the wetland may include surface water, groundwater or a combination of these sources. Some wetlands receive groundwater directly from subsurface water or from groundwater while other simulated wetlands receive groundwater as a proportion of runoff and river flows. Interactions between the wetland and the catchment, surface water, groundwater and river are possible. The difference between wetland-surface water interactions and wetland-river interactions is that the former represents the channel inflow component in the water balance and is at the upstream end of the wetland while the latter refers to the interactions between the wetland and the river of the (sub)catchment (this could be at the downstream or upstream end of the wetland). Water losses from the wetland to groundwater, the surrounding catchment and the channel, another important water loss is through evapotranspiration.

@@ Line 6: / Line 6: @@
 This information serves as a standard and comparable starting point for describing the physical wetland. If the situation allows, this information can be supplemented with information from local monitoring.
 The criteria for assessing the suitability of a simulated wetland are based on how the modelling tool deviates from the standard definition of simulated wetland and other critical differences. At a very basic level, a simulated wetland is a depressional landscape that forms a water storage unit regulated by a water balance of temporally variable inflows and outflows (Rahman et al., 2016)<sup>[https://doi.org/10.1016/j.envsoft.2016.07.003 5]</sup>. The main, reoccurring differences from this definition occur through the following features in the simulated wetland concept:
@@ Line 34: / Line 35: @@
 In some modelling tools, the alternative wetland type can be implied by modifying the setup of the wetland unit in the catchment and how water is routed through the catchment.
-For example, a simulated wetland in ACRU-4 was designed to represent riparian wetlands. However, GIWs can be represented by splitting one catchment into two subcatchments, with the upland subcatchment containing riparian wetlands to act as GIWs (Gray, 2011)<sup>[http://hdl.handle.net/10413/8076 6]</sup>. Water from the GIW is then routed to the downstream subcatchment.
+For example, a simulated wetland in ACRU-4 was designed to represent riparian wetlands. However, GIWs can be represented by splitting one catchment into two subcatchments, with the upland subcatchment containing riparian wetlands to act as GIWs (Gray, 2011)<sup>[http://hdl.handle.net/10413/8076 6]</sup>.
-All modelling tools except for SWAT conceptualise its simulated wetland as riparian wetlands. In the case of SWAT, a riparian wetland can be modelled using modified versions of SWAT available from independent researchers. As another example of modifying setups to infer a wetland type, Rahman et al. (2016)<sup>3</sup> developed a version of SWAT with riparian wetlands by changing the internal mechanisms of the model to allow the wetland to receive water from the river as opposed to the wetland only contributing water to the river. Alternatively, WRSM-Pitman as a conceptual, modular and parameterised model is equipped with the option to represent GIWs by indicating through a parameter that the wetland is an off-channel storage system.
+Alternatively, WRSM-Pitman as a conceptual, modular and parameterised model is equipped with the option to represent GIWs by indicating through a parameter that the wetland is an off-channel storage system.
 While simulated wetlands consider the wetland type as an indicator of the wetland’s connection to the river, physical GIWs are not necessarily under the same restriction (GIWs can be functionally connected to the river network as reported in Yeo et al. (2019)<sup>[https://doi.org/10.1016/j.scitotenv.2018.11.237 7]</sup>).
@@ Line 81: / Line 88: @@
 The inflows and outflows of a simulated wetland water balance are indicators of the water sources available to the wetland and that the wetland can contribute to.
-An illustrative summary of the wetland water balances in each modelling tool is presented in '''Figure 1'''. Most of the simulated wetlands receive surface water and rainfall as the main inflow with groundwater incorporated into the surface water flow pathway. ACRU and MIKE-SHE are the only tools with wetlands that have a separate inflow of groundwater. WRSM-Pitman and SWAT do not have direct groundwater outflows. In these tools, the wetlands contribution to groundwater is through baseflow and seepage losses, respectively. All modelling tools can account for water losses through evapotranspiration.
+An illustrative summary of the wetland water balances in each modelling tool is presented in '''Figure 1a-e'''. Most of the simulated wetlands receive surface water and rainfall as the main inflow with groundwater incorporated into the surface water flow pathway. ACRU and MIKE-SHE are the only tools with wetlands that have a separate inflow of groundwater. WRSM-Pitman and SWAT do not have direct groundwater outflows. In these tools, the wetlands contribution to groundwater is through baseflow and seepage losses, respectively. All modelling tools can account for water losses through evapotranspiration.
 {| class="wikitable"
@@ Line 88: / Line 95: @@
 !Water balance
 |-
-|style="background:#F2CEE0;" |WRSM-Pitman
+| style="background:#F2CEE0;" |'''WRSM-Pitman'''
-|style="background:#FFF5FA;" |[[File:Img updated WB wrsm-pitman.jpg|center|thumb|900x900px|Figure 1a]]
+| style="background:#FFF5FA;" |[[File:Img updated WB wrsm-pitman.jpg|center|thumb|900x900px|Figure 1a]]
 |-
-| style="background:#F2D4CE;" |SPATSIM-Pitman
+| style="background:#F2D4CE;" |'''SPATSIM-Pitman'''
-|style="background:#FFF7F5;" |[[File:Img updated WB SPATSIM-pitman.jpg|thumb|900x900px|Figure 1b]]
+| style="background:#FFF7F5;" |[[File:Img updated WB SPATSIM-pitman.jpg|thumb|900x900px|Figure 1b|alt=|center]]
 |-
-| style="background:#CEF2CE;" |ACRU
+| style="background:#CEF2CE;" |'''ACRU'''
-|style="background:#F5FFF5;" |[[File:Img updated WB acru.jpg|center|thumb|900x900px|Figure 1c]]
+| style="background:#F5FFF5;" |[[File:Img updated WB acru.jpg|center|thumb|900x900px|Figure 1c]]
 |-
-| style="background:#F2F2CE;" |SWAT
+| style="background:#F2F2CE;" |'''SWAT'''
-|style="background:#FFFFF5;" |[[File:Img updated WB swat.jpg|thumb|900x900px|Figure 1d]]
+| style="background:#FFFFF5;" |[[File:Img updated WB swat.jpg|thumb|900x900px|Figure 1d|alt=|center]]
 |-
-|style="background:#CEE6F2;" |MIKE-SHE
+| style="background:#CEE6F2;" |'''MIKE-SHE'''
-| style="background:#F5F8FF;" |[[File:Img updated WB mike-she.jpg|thumb|900x900px|Figure 1e]]
+| style="background:#F5F8FF;" |[[File:Img updated WB mike-she.jpg|thumb|900x900px|Figure 1e|alt=|center]]
 |}
 ==Interactions controlling the wetland’s access to water ==
@@ Line 159: / Line 164: @@
 == References==
 <small>This page presents material adapted from Metho, 2021, A case study approach comparing wetland representation in hydrological models when estimating water availability for long-term averages, and short-term floods and droughts, MSc dissertation, UCT, supported (in-part) by the WRC project “Critical catchment model inter-comparison and model use guidance development” (2019-2021) '''(add link to project background page)'''</small>

@@ Line 81: / Line 81: @@
 The inflows and outflows of a simulated wetland water balance are indicators of the water sources available to the wetland and that the wetland can contribute to.
 An illustrative summary of the wetland water balances in each modelling tool is presented in '''Figure 1'''. Most of the simulated wetlands receive surface water and rainfall as the main inflow with groundwater incorporated into the surface water flow pathway. ACRU and MIKE-SHE are the only tools with wetlands that have a separate inflow of groundwater. WRSM-Pitman and SWAT do not have direct groundwater outflows. In these tools, the wetlands contribution to groundwater is through baseflow and seepage losses, respectively. All modelling tools can account for water losses through evapotranspiration.
- [[File:Img updated WB SPATSIM-pitman.jpg|thumb|700x700px|Figure 1b. Wetland water balance in SPATSIM-Pitman]]
+{| class="wikitable"
-[[File:Img updated WB wrsm-pitman.jpg|left|thumb|700x700px|Figure 1a. Wetland water balance in WRSM-Pitman ]]
+|+Wetland water balances in each modelling tool