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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. |
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| 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]]. |
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| 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. |
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| 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. |
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| ===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: | | :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. |
| * [[Rainfall_(Overlay)|Rainfall Overlay]], provides insight into the water stress caused by (excessive) rainfall.
| | ;[[Hydraulic structures (Water Overlay)|Hydraulic structures]] |
| * [[Flooding_(Overlay)|Flooding Overlay]], provides insight into water stress caused by breaches in levees or other sources causing excessive water inflow.
| | :See [[Hydraulic structures (Water Overlay)|Hydraulic structures]] for the list of supported structures. |
| * [[Groundwater_(Overlay)|Groundwater Overlay]], provides insight into long-term processes of water flow both on the surface and underground.
| | ;[[Additional_hydrological_attributes_of_buildings_(Water Overlay)|Hydrological attributes of buildings]] |
| | :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]]. |
| | ;[[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 building is present with overwriting values. For a full list, see [[Terrain_attributes_(Water_Overlay)| Terrain attributes for the water overlay]]. |
| | ;[[Model_attributes_(Water_Overlay)|Model settings]] |
| | :For a full list, see: [[Model_attributes_(Water_Overlay)|Water Model attributes]] |
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| ===Use cases=== | | ==Troubleshoot, warnings and recommendations== |
| {{main|Use cases Water Overlay}}
| | 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. |
| {{stub|type=section}}
| | See [[Warning_and_recommendations_(Water_Overlay)|Troubleshoot, warnings and recommendations]]; |
| 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]].
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| ==How to use the Water overlay==
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| <onlyinclude>{{#if:{{{how to use|<noinclude>main</noinclude>}}}|<!--
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| -->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.
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| 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.
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| 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.<!--
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| ===Prerequisites===
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| <onlyinclude>{{#if:{{{prerequisites|<noinclude>main</noinclude>}}}|<!--
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| -->When creating your [[project]], make sure it meets the following criteria:
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| * 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]].
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| * Your project is large enough to account for {{#if:<noinclude>main</noinclude>|{{inlink|Model border|edge effects}}|[[Water_Overlays#Model border|edge effects]]}}.<!--
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| --><includeonly>
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| For more tips for preparation and use, see the [[Water Overlay#Additional tips for preparation and use|Water Overlay]] page.</includeonly><!--
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| ===Additional tips for preparation and use===
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| <onlyinclude>{{#if:{{{tips|<noinclude>main</noinclude>}}}|<!--
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| -->There are a number of additional points of attention when creating a project with the intent of using this overlay:
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| * 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.
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| * 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.
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| * 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.
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| * 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.<!--
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| ==Configuration==
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| See: [[Water Overlay Configuration]]
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| ==Results== | | ==Results== |
| See [[Results_(Water_Overlay)|results]].
| | 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]]. |
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| ==Data==
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| 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.
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| ===Hydrological features===
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| 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.
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| ===Hydraulic stuctures===
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| See [[Hydraulic structures (Water Overlay)|Hydraulic structures]] for the list of supported structures.
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| ===Hydrological attributes of constructions===
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| 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.
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| For a full list, see [[Additional_hydrological_attributes_of_constructions_(Water Overlay)|Additional hydrological attributes of constructions]]. | |
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| ===Hydrological attributes of terrain===
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| [[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.
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| For a full list, see [[Terrain_attributes_(Water_Overlay)| Terrain attributes for the water overlay]].
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| ===Model connections===
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| To gain insight into how this Water Overlay ties together several models, see [[Model_connections_(Water_Overlay)|Model connections]].
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| ==Settings== | | ==How-to's== |
| 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.
| | * [[How to add and remove an Overlay]] |
| | * [[How to manually configure a Water Overlay|Configure a Water Overlay]] |
| | * [[How to edit an overlay legend|Edit an overlay legend]] |
| | * [[How to add Subsidence (Water Overlay)|Combine with Subsidence Overlay]] |
| | * [[Water Model Limits]] (some basic rules) |
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| ===Result type=== | | ===Features and components=== |
| {{Editor ribbon|header=Current situation|bar=Overlays|left panel=The overlay|right panel=General tab}}
| | * [[Hydrological features (Water Overlay)|Hydrological features]] |
| {{main|Result_type_(Water_Overlay)|Result types}}
| | * [[Hydraulic structures (Water Overlay)|Hydraulic structures]] |
| | | * [[How to_manually_configure_a_Water_Overlay|Manual configuration Options]] |
| ===Keys===
| | * [[Simulation data (Water Overlay)|Simulation data]] |
| 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.
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| 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.
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| ===Attributes=== | | ===Attributes=== |
| {{main|Model_attributes_(Water_Overlay)|Water Model attributes}}
| | * [[Model attributes (Water Overlay)|Water Module Attributes]] |
| | | * [[Hydrological attributes of buildings (Water Overlay)|Hydrological Attributes of Buildings]] |
| ==Calculations==
| | * [[Hydrological attributes of terrains (Water Overlay)|Hydrological Attributes of Terrains]] |
| 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.
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| ===Models===
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| Multiple models are implemented which in conjunction form the water model in its entirety.
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| * [[Surface_model_(Water_Overlay)|Surface model]] | |
| * [[Underground_model_(Water_Overlay)|Underground model]] | |
| * [[Rain_model_(Water_Overlay)|Rain model]]
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| * [[Evaporation model (Water Overlay)|Evaporation model]]
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| * [[Sewer_model_(Water_Overlay)|Sewer model]] | |
| * [[Storage_model_(Water_Overlay)| Storage model]]
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| * [[Chemical_flow_model_(Water_Overlay)|Chemical flow model]]
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| * [[Border_model_(Water_Overlay)|Border model]]
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| ===Formulas===
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| The precise calculations which govern the water overlay's simulation are many and varied, and based as much as possible on available expert knowledge.
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| Model related Formula's:
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| * [[Timestep_formula_(Water_Overlay)|Timestep formula]]
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| * [[Calculation_preference_formula_(Water_Overlay)|Calculation preference formula]]
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| * [[Surface_water_level_formula_(Water_Overlay)|Surface water level formula]]
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| * [[Groundwater_level_formula_(Water_Overlay)|Groundwater level formula]]
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| * [[Surface_flow_formula_(Water_Overlay)|Surface flow formula]]
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| * [[Underground_flow_formula_(Water_Overlay)|Underground flow formula]]
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| * [[Surface_evaporation_formula_(Water_Overlay)|Surface evaporation formula]]
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| * [[Underground_evaporation_formula_(Water_Overlay)|Underground evaporation formula]]
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| * [[Surface_infiltration_formula_(Water_Overlay)|Surface infiltration formula]]
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| * [[Underground_infiltration_formula_(Water_Overlay)|Underground infiltration formula]]
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| Hydraulic structure related Formula's:
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| * [[Culvert_formula_(Water_Overlay)|Culvert formula]]
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| * [[Weir_formula_(Water_Overlay)|Weir formula]]
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| * [[Breach_growth_formula_(Water_Overlay)|Breach growth formula]]
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| * [[Breach_flow_formula_(Water_Overlay)|Breach flow formula]]
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| * [[Pump_formula_(Water_Overlay)|Pump formula]]
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| * [[Sewer_Overflow_formula_(Water_Overlay)|Sewer Overflow formula]]
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| * [[Inlet_formula_(Water_Overlay)|Inlet formula]]
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| ===Computational structure===
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| {{stub|type=section}}
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| 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.
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| ====Order of operations====
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| 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.
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| Calculations are performed in the following order:
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| * Horizontal surface flow and horizontal underground flow
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| * Rain
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| * Building storage
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| * Sewer inflow
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| * Surface evaporation
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| * Groundwater evaporation (saturated zone)
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| * Groundwater evaporation (unsaturated zone)
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| * Underground infiltration
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| * Surface infiltration
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| * Exfiltration
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| * Hydrological constructions (culverts, weirs, pumps, in- and outlets, outlets)
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| * Hydrological areas (sewer overflow, breach in- and outflow)
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| * Chemical movement, based on the water flow and infiltration which has occurred
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| ==Warnings and recommendations==
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| 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.
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| ===Configuration wizard warnings===
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| While configuring the water overlay using the {{inlink|lcase=1|Configuration wizard}}, each type of {{inlink|lcase=1|Data}} loaded in or found in the project must meet certain requirements to be functional. For example, configured {{inlink|WATER_LEVEL|water levels}} may deviate greatly from the mean terrain height in the project, or certain {{inlink|lcase=1|Hydrological constructions}} may not be shaped appropriately or intersect with required features. In these cases, the configuration wizard will show the warnings in the steps related to the specific type of data.
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| ===Inaccurate terrain===
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| When the [[Terrain_height#Terrain_height_in_the_Tygron_Platform|project is created]], the advanced options allow for selecting a high-resolution height map to be loaded in. The default, low resolution height map can introduce artifacts in the calculation due to inaccuracy. This issue can currently only be resolved by reloading the project area.
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| ===Calculation halted===
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| If the overlay is recalculated, but the [[Recalculate indicators|(re)calculation is halted]], the water overlay will not contain meaningful results. A warning will be displayed indicating that the calculation did not complete.
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| ===Large cell size===
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| The water overlay performs its calculations based on a discretization of the project area. This means both that areas of water are considered a single block, and that obstacles and hydrological properties are averaged out over the extent of a cell. To best approach a realistic, continuous water flow and a realistic model of obstacles and values, it is sufficient to reduce the size of the cells the calculation uses.
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| ===Limited cycles===
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| {{stub|type=section}}
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| ====Calculation time impacts====
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| {{stub|type=section}}
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| <!--==References==
| | {{WaterOverlay output nav}} |
| <references>
| | {{Overlay nav}} |
| <ref name="hydradius">DUFLOW manual ∙ found at: http://resolver.tudelft.nl/uuid:97184101-cc3b-483a-bba0-3d2bfdf31cdd ∙ (last visited 2019-03-08)</ref>
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| </references>-->
| | [[Category:Water Module]][[Category:Overlays with result types]] |
