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{{learned|what the Water Overlay is|what use-cases the Water Overlay can be applied to|what data is required to fully configure the Water Overlay|what options are available to configure the Water Overlay|how to analyse the results of the Water Overlay|how the Water Overlay's functionality has been implemented}}
A Water Overlay is a [[Grid Overlay|grid overlay]] for which results are calculated by the [[Water Module]]. The [[Water_Module_Basics|Basic theory of the Water Module]] in the {{software}} is an implementation of a 2D grid based shallow water model based on the 2D Saint Venant equations. The module is further enhanced with infiltration, evaporation, groundwater flow and hydraulic structures. Depending on the use case, the simulated period can be set to few seconds and up to a few months. The [[Water_Module_Theory|theory]] section describes in detail how calculations are performed.
==What is the Water overlay==
__NOTOC__
The water [[Overlay|overlay]] is an implementation of a large number of hydrological formulas which together can simulate the flow of water across large areas with a high level of detail. Its calculations form a simulation of an arbitrary amount of time, during which water is allowed to move.
To perform the calculations, the project area is divided into a [[Grid overlay|grid of cells]]. Each cell has a specific quantity of water and specific hydrological parameters based on the data in the project. The total time which should be simulated is divided into discrete [[Timestep formula (Water Overlay)|timesteps]]. Per timestep, each cell communicates with its adjacent cells to exchange water, based on its water level, surface height, current flow direction and other factors. Accuracy and reliability is obtained by dividing the project area and simulation time into sufficiently small cells and steps, at the cost of more computation time.


Water flow is affected by properties of the surface across which it flows, including the [[terrain height]] and the properties of the underlying [[terrain]].
The final results of the calculation can be inspected, as well as intermediate snapshots of the hydrological situation during the simulation, known as [[Timeframes (Water Overlay)|timeframes]].


To perform the calculations, the project area is divided into a [[Grid overlay|grid of cells]]. Each cell has a specific quantity of water, and specific hydrological parameters based on the data in the project. The total time which should be simulated is divided into discrete {{inlink|Timestep formula|timesteps}}. Per timestep, every cell communicates with all adjacent cells to exchange water. By dividing the project area and simulation time into sufficiently small cells and steps the behavior becomes effective continuous.
==Variants==
A Water Module will be initialized by adding one of the following Overlays to a project. Each variant has a number of parameters tuned to best fit specific use-cases. This means that each of these overlays is based on the same theory and calculation method, however they are customized to conveniently provide insight in different aspects of the Water Module.
{| class="wikitable"
|[[File:Overlay_rainfall.png]]
|[[Rainfall_(Overlay)|Rainfall Overlay]]
|provides insight into the water stress and impact caused by (excessive) rainfall
|-
|[[File:Overlay_flooding.png]]
|[[Flooding_(Overlay)|Flooding Overlay]]
|provides insight into water stress and impact caused by breaches in levees or other sources causing excessive water inflow
|-
||[[File:Overlay_groundwater.png]]
|[[Groundwater_(Overlay)|Groundwater Overlay]]
|provides insight into long-term processes of water flow both on the surface and underground
|}
<!--==Input Data and Settings==
The calculations performed by the Water Overlay are influenced by many kinds of geographical information present in the project area. For any given location, [[terrain]], [[construction]]s and other features can influence either the initial state of the simulation or how water flows in a given area.


The final results of the calculation can be inspected, as well as snapshots of the hydrological situation in the simulation, known as {{inlink|lcase=1|Timeframes}}.
Furthermore, the Water Overlay features a number of overall settings which can be configured for the hydrological calculations and its results. These settings do not have a geographical or temporal element to them, and are fixed values relevant for the simulation as a whole.


===Variants===
;[[Hydrologic_features_(Water_Overlay)|Hydrological features]]
The water overlay can be added to a project as one of a number of variants. Each variant has a number of parameters tuned to best fit certain use-cases. The following preconfigured variants exist:
* [[Rainfall_(Overlay)|Rainfall Overlay]], provides insight into the water stress caused by (excessive) rainfall.
* [[Flooding_(Overlay)|Flooding Overlay]], provides insight into water stress caused by breaches in levees or other sources causing excessive water inflow.
* [[Groundwater_(Overlay)|Groundwater Overlay]], provides insight into long-term processes of water flow both on the surface and underground.
 
===Use cases===
The water overlay is complex and versatile, and can configured for a large number of different detailed use cases.
Due to the complexity of the water overlay, if an exact understanding of the functioning of the water overlay is not required or desired, it may be preferable to follow the instructions to complete one or more specific use cases, as found on the [[Use cases Water Overlay|water overlay's use cases page]].
{{main|Use cases Water Overlay}}
 
==How to use the Water overlay==
<onlyinclude>{{#if:{{{how to use|<noinclude>main</noinclude>}}}|<!--
 
-->In general, when a water overlay is added to a project it will immediately be capable of calculating results. However, these will be based on default settings and will at best give a broad sense of water stress.
 
To use any variant of the overlay properly, it is recommended that you ensure the project meets a number of {{inlink|lcase=1|Prerequisites}}. Next, it is recommended to prepare all {{inlink|Data|data related to the hydrological model}}, which defines the functioning and flow of the water. Included in this preparation is a clear idea of the {{inlink|{{#if:<noinclude>main</noinclude>|Model connections|Calculation properties}}|climate conditions}} and what kind of {{inlink|{{#if:<noinclude>main</noinclude>|Result type|Result types}}|output}} is desired. After these preparations have been made, {{inlink|{{#if:<noinclude>main</noinclude>|Configuration|Adding and configuring the overlay}}|creation and configuration}} of the overlay can begin. When the configuration is completed, a [[Grid overlay#Grid recalculation|recalculation]] of the overlay will yield more accurate and appropriate results.
 
After the overlay has calculated results, a number of means exist to {{inlink|{{#if:<noinclude>main</noinclude>|Results|Data analysis}}|analyse the results}} of the calculation performed.<!--
 
-->|}}</onlyinclude>
 
===Prerequisites===
<onlyinclude>{{#if:{{{prerequisites|<noinclude>main</noinclude>}}}|<!--
 
-->When creating your [[project]], make sure it meets the following criteria:
* Your project has been loaded in with a high-resolution DEM. This can be configured during the [[Terrain_height#Terrain_height_in_the_Tygron_Platform|new project wizard]].
* Your project is large enough to account for {{#if:<noinclude>main</noinclude>|{{inlink|Model border|edge effects}}|[[Water_Overlays#Model border|edge effects]]}}.<!--
--><includeonly>
For more tips for preparation and use, see the [[Water Overlay#Additional tips for preparation and use|Water Overlay]] page.</includeonly><!--
 
-->|}}</onlyinclude>
 
===Additional tips for preparation and use===
<onlyinclude>{{#if:{{{tips|<noinclude>main</noinclude>}}}|<!--
 
-->There are a number of additional points of attention when creating a project with the intent of using this overlay:
* When creating a new project in the [[Wizard|new project wizard]], consider using the [[GEO_Data#AHN3|AHN3]] dataset rather than the default AHN2. Where coverage is available, the AHN3 dataset will be more accurate. Where coverage is not available, the default AHN2 should be used.
* Additionally, when creating a new project, consider whether you want to use the [[GEO_Data#IMWA|IMWA]] dataset for {{#if:<noinclude>main</noinclude>|{{inlink|lcase=1|Hydrological constructions}}|[[Water_Overlays#Hydrological constructions|hydrological constructions]]}}. Although this dataset is not complete, some information about constructions which serve as {{#if:<noinclude>main</noinclude>|{{inlink|lcase=1|Culvert}}|[[Water Overlay#Culvert|culvert]]}}s other relevant objects can be loaded in from this datasource. If more complete or accurate data is available to be loaded in into the project after it is created, it may be desirable to disregard this source so that hydrological constructions are not doubly included.
* Water flow can often be dictated by small features in an area, such as small openings between buildings, and thin [[levee]]s. To have these small features included properly in the calculations, the {{#if:<noinclude>main</noinclude>|{{inlink|Grid cell size configuration|grid cell size}}|[[Water Overlay#Grid cell size configuration|grid cell size]]}} will need to be set to an appropriate size. The default setting offered by the {{software}} will often need to be adjusted to allow for smaller features to be recognized without having their presence averaged out with their surroundings.
* The water overlay performs a complete simulation, which is a series of complex calculations across multiple layers. Depending on the configuration of the overlay, the {{#if:<noinclude>main</noinclude>|{{inlink|Calculation time impacts|calculation time}}|[[Water Overlay#Calculation time impacts|calculation time]]}} can range from seconds to hours. If the overlay is to be used in a setting where response times need to be short, it may be preferable to configure the overlay for greater speed rather than excessive precision.<!--
 
-->|}}</onlyinclude>
 
==Configuration==
See: [[Water Overlay Configuration]]
 
==Results==
See [[Results_(Water_Overlay)|results]].
 
==Data==
The calculations performed by the water overlay are influenced by many kinds of geographical information present in the project area. For any given location, [[terrain]], [[construction]]s and other features can influence either the initial state of the simulation or how water flows in a given area.
 
;[[Hydrologic_features_(Water_Overlay)|Hydological features]]
:The water system can be enhanced with a number of hydrological features, which can be loaded in as [[area]]s. These hydrological features form special properties or modifications on the hydrological system. See [[Hydrologic_features_(Water_Overlay)|Hydological features]] for a list of supported features.
:The water system can be enhanced with a number of hydrological features, which can be loaded in as [[area]]s. These hydrological features form special properties or modifications on the hydrological system. See [[Hydrologic_features_(Water_Overlay)|Hydological features]] for a list of supported features.
;[[Hydraulic structures (Water Overlay)|Hydraulic structures]]
;[[Hydraulic structures (Water Overlay)|Hydraulic structures]]
:See [[Hydraulic structures (Water Overlay)|Hydraulic structures]] for the list of supported structures.
:See [[Hydraulic structures (Water Overlay)|Hydraulic structures]] for the list of supported structures.
;Hydrological attributes of constructions
;[[Additional_hydrological_attributes_of_buildings_(Water Overlay)|Hydrological attributes of buildings]]
:Besides the [[construction]]s which directly influence the hydrologic model as a [[Hydraulic structure|hydraulic structure]], each construction may also have attributes which can contribute to the hydrological model in some way. These attributes are stored and used on a grid cell level. This is different from the hydraulic structure attributes, which are stored and used on an object level. For a full list, see [[Additional_hydrological_attributes_of_constructions_(Water Overlay)|Additional hydrological attributes of constructions]].
:Besides the [[building]]s which directly influence the hydrologic model as a [[Hydraulic structures (Water Overlay)|hydraulic structure]], each building may also have attributes which can contribute to the hydrological model in some way. These attributes are stored and used on a grid cell level. This is different from the hydraulic structure attributes, which are stored and used on an object level. For a full list, see [[Additional_hydrological_attributes_of_buildings_(Water Overlay)|Additional hydrological attributes of buildings]].
;Hydrological attributes of terrain
;[[Terrain_attributes_(Water_Overlay)| Hydrological attributes of terrain]]
:[[Terrain]]s in a project have a number of hydrological attributes which can influence the flow of water in a project. Because there is always both surface and underground terrain defined for the entirety of the project area, all cells are affected by all attributes of terrains, unless a construction is present with overwriting values. For a full list, see [[Terrain_attributes_(Water_Overlay)| Terrain attributes for the water overlay]].
:[[Terrain]]s in a project have a number of hydrological attributes which can influence the flow of water in a project. Because there is always both surface and underground terrain defined for the entirety of the project area, all cells are affected by all attributes of terrains, unless a building is present with overwriting values. For a full list, see [[Terrain_attributes_(Water_Overlay)| Terrain attributes for the water overlay]].
;Model settings
;[[Model_attributes_(Water_Overlay)|Model settings]]
:{{main|Model_attributes_(Water_Overlay)|Water Model attributes}}
:For a full list, see: [[Model_attributes_(Water_Overlay)|Water Model attributes]]


==Troubleshoot, warnings and recommendations==
When the Water Overlay is used and calculations take place, there are some problems or points of attention the calculation can run into. Where possible, the Water Overlay will show appropriate warnings when running into any issues.
See [[Warning_and_recommendations_(Water_Overlay)|Troubleshoot, warnings and recommendations]];
-->


==Model connections==
==Results==
To gain insight into how this Water Overlay ties together several models, see [[Model_connections_(Water_Overlay)|Model connections]].
With a Water Overlay, a user can generate multiple [[Results_(Water_Overlay)|results]] for a single water simulation. For further information about these outcomes, see also [[Results_(Water_Overlay)|results]] and [[Result type (Water Overlay)|result types]].
 
==Settings==
The water overlay features a number of overall settings which can be configured for the hydrological calculations and its results. These settings do not have a geographical or temporal element to them, and are fixed values relevant for the complete simulation.
 
===Result type===
{{Editor ribbon|header=Current situation|bar=Overlays|left panel=The overlay|right panel=General tab}}
{{main|Result_type_(Water_Overlay)|Result types}}
 
===Keys===
The water model makes use of data present in geographical features in the [[3D world]]. This data is used as input for the various calculations which together model the water flow. The water model recognizes what attributes of geographical features form the parameters required for the calculation through key definitions. Each key is the name of an attribute which the water model should use to determine a specific parameter.
 
Keys are set to default attribute names, which apply to {{inlink|lcase=1|Hydrological features}}, {{inlink|lcase=1|Hydrological constructions}}, and {{inlink|lcase=1|Hydrological properties of terrain}}. Keys can be changed so that imported data can be interpreted without renaming attributes, or to allow different configurations to come forth from the same dataset.
 
==Calculations==
The water overlay performs a large number of calculations to form a complete hydrological simulation. Depending on the desired viewpoint, both the overarching concepts as well as the implemented formulas can be reviewed for detailed insight into how the water overlay works.
 
===Models===
Multiple models are implemented which in conjunction form the water model in its entirety.
 
* [[Surface_model_(Water_Overlay)|Surface model]]
* [[Underground_model_(Water_Overlay)|Underground model]]
* [[Rain_model_(Water_Overlay)|Rain model]]
* [[Evaporation model (Water Overlay)|Evaporation model]]
* [[Sewer_model_(Water_Overlay)|Sewer model]]
* [[Storage_model_(Water_Overlay)| Storage model]]
* [[Chemical_flow_model_(Water_Overlay)|Chemical flow model]]
* [[Border_model_(Water_Overlay)|Border model]]
 
===Formulas===
The precise calculations which govern the water overlay's simulation are many and varied, and based as much as possible on available expert knowledge.
 
Model related Formula's:
* [[Timestep_formula_(Water_Overlay)|Timestep formula]]
* [[Calculation_preference_formula_(Water_Overlay)|Calculation preference formula]]
* [[Surface_water_level_formula_(Water_Overlay)|Surface water level formula]]
* [[Groundwater_level_formula_(Water_Overlay)|Groundwater level formula]]
* [[Surface_flow_formula_(Water_Overlay)|Surface flow formula]]
* [[Underground_flow_formula_(Water_Overlay)|Underground flow formula]]
* [[Surface_evaporation_formula_(Water_Overlay)|Surface evaporation formula]]
* [[Underground_evaporation_formula_(Water_Overlay)|Underground evaporation formula]]
* [[Surface_infiltration_formula_(Water_Overlay)|Surface infiltration formula]]
* [[Underground_infiltration_formula_(Water_Overlay)|Underground infiltration formula]]


Hydraulic structure related Formula's:
==How-to's==
* [[Culvert_formula_(Water_Overlay)|Culvert formula]]
* [[How to add and remove an Overlay]]
* [[Weir_formula_(Water_Overlay)|Weir formula]]
* [[How to manually configure a Water Overlay|Configure a Water Overlay]]
* [[Breach_growth_formula_(Water_Overlay)|Breach growth formula]]
* [[How to edit an overlay legend|Edit an overlay legend]]
* [[Breach_flow_formula_(Water_Overlay)|Breach flow formula]]
* [[How to add Subsidence (Water Overlay)|Combine with Subsidence Overlay]]
* [[Pump_formula_(Water_Overlay)|Pump formula]]
* [[Water Model Limits]] (some basic rules)
* [[Sewer_Overflow_formula_(Water_Overlay)|Sewer Overflow formula]]
* [[Inlet_formula_(Water_Overlay)|Inlet formula]]


===Computational structure===
===Features and components===
{{stub|type=section}}
* [[Hydrological features (Water Overlay)|Hydrological features]]
The formulas and concepts come together in a single computational structure which is repeated a large number of times until the total simulation duration has been reached.
* [[Hydraulic structures (Water Overlay)|Hydraulic structures]]
* [[How to_manually_configure_a_Water_Overlay|Manual configuration Options]]
* [[Simulation data (Water Overlay)|Simulation data]]


====Order of operations====
===Attributes===
During the calculation, multiple facets have to be calculated. In each timestep, each aspect of the calculation has to be performed. Although as timesteps become smaller exact order of operation becomes less important, the order of operations can lead to specific behavioral details in some edge cases.
* [[Model attributes (Water Overlay)|Water Module Attributes]]
* [[Hydrological attributes of buildings (Water Overlay)|Hydrological Attributes of Buildings]]
* [[Hydrological attributes of terrains (Water Overlay)|Hydrological Attributes of Terrains]]


Calculations are performed in the following order:
{{WaterOverlay output nav}}
* Horizontal surface flow and horizontal underground flow
{{Overlay nav}}
* Rain
* Building storage
* Sewer inflow
* Surface evaporation
* Groundwater evaporation (saturated zone)
* Groundwater evaporation (unsaturated zone)
* Underground infiltration
* Surface infiltration
* Exfiltration
* Hydrological constructions (culverts, weirs, pumps, in- and outlets, outlets)
* Hydrological areas (sewer overflow, breach in- and outflow)
* Chemical movement, based on the water flow and infiltration which has occurred


==Warnings and recommendations==
[[Category:Water Module]][[Category:Overlays with result types]]
When the water overlay is used and calculations take place, there are some problems or points of attention the calculation can run into. Where possible, the water overlay will show appropriate warnings when running into any issues.

Latest revision as of 13:40, 17 January 2023

A Water Overlay is a grid overlay for which results are calculated by the Water Module. The Basic theory of the Water Module in the Tygron Platform is an implementation of a 2D grid based shallow water model based on the 2D Saint Venant equations. The module is further enhanced with infiltration, evaporation, groundwater flow and hydraulic structures. Depending on the use case, the simulated period can be set to few seconds and up to a few months. The theory section describes in detail how calculations are performed.

To perform the calculations, the project area is divided into a grid of cells. Each cell has a specific quantity of water and specific hydrological parameters based on the data in the project. The total time which should be simulated is divided into discrete timesteps. Per timestep, each cell communicates with its adjacent cells to exchange water, based on its water level, surface height, current flow direction and other factors. Accuracy and reliability is obtained by dividing the project area and simulation time into sufficiently small cells and steps, at the cost of more computation time.

The final results of the calculation can be inspected, as well as intermediate snapshots of the hydrological situation during the simulation, known as timeframes.

Variants

A Water Module will be initialized by adding one of the following Overlays to a project. Each variant has a number of parameters tuned to best fit specific use-cases. This means that each of these overlays is based on the same theory and calculation method, however they are customized to conveniently provide insight in different aspects of the Water Module.

Overlay rainfall.png Rainfall Overlay provides insight into the water stress and impact caused by (excessive) rainfall
Overlay flooding.png Flooding Overlay provides insight into water stress and impact caused by breaches in levees or other sources causing excessive water inflow
Overlay groundwater.png Groundwater Overlay provides insight into long-term processes of water flow both on the surface and underground

Results

With a Water Overlay, a user can generate multiple results for a single water simulation. For further information about these outcomes, see also results and result types.

How-to's

Features and components

Attributes