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| {{learned|what the Water Overlays are|how to configure the Water Overlays}} | | 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. |
| | __NOTOC__ |
| | 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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| ==What are the Water Overlays==
| | 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]]. |
| With the Water Overlays the following overlays are meant:
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| * [[Rainfall_(Overlay)|Rainfall Overlay]]
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| * [[Flooding_(Overlay)|Flooding Overlay]]
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| * [[Groundwater_(Overlay)|Groundwater Overlay]]
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| Each of these overlays have some common configuration steps which will be described on this page.
| | ==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. |
| ==Tips on creating a new project when working with the Water Overlays== | |
| When creating a new project in the [[Wizard|new project wizard]], take into account the [[Terrain_height#Terrain_height_in_the_Tygron_Platform|Advanced options]]. In this menu for example the [[GEO_Data|AHN3]] dataset can be selected, which, if available for your project area provides the most recent heightdata available as Open Data. Also, the [[GEO_Data|IMWA]] dataset is already checked, this means that if available in your project area, Water Level areas and/or Culverts are already imported.
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| ==Configuration Wizard==
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| Each of the Water Overlays has a configuration wizard which helps the user with configuring the overlay.
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| The Configuration Wizard can be found in the General tab of the overlay. <br>
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| [[File:Config_wizard.JPG|900px]] <br>
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| For the [[Flooding_(Overlay)|Flooding Overlay]] the wizard has an extra step, the [[Rainfall_(Overlay)|Rainfall]] and [[Groundwater_(Overlay)|Groundwater Overlay]] wizard are basically the same.
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| The settings in the wizard can always be changed after finishing the wizard by opening the wizard again and changing a value and recalculating the overlay.
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| <br>'''Step 1'''
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| In the first step the simulation time is set, based on either a rainfall or without a rainfall. Also the evaporation reference factor (over time) can be set.
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| <br>'''Step 2'''
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| In the second step the elements of the water system can be imported. In some sub-steps the there are four options: to do nothing and proceed, to import the data with the [[Geo_Data_Wizard|Geo data wizard], or when you already have the data imported to select it based on an attribute of the data or to let the {{software}} automatically generate some data.
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| The following elements can be imported:
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| * the breach areas (only for the [[Flooding_(Overlay)|Flooding overlay]]
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| * water level areas; when automatically generating data one water level area covering the whole project area is created. The water level can be adjusted afterwards.
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| * ground water data
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| * sewer areas; can also be automatically generated based on the urbanization of the project area
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| * inundated areas; these are areas that are already inundated at the start of the flooding
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| * constructions; for the constructions keep in mind that when the data is point data, it has to overlap two water level areas. Therefore make sure the point data is on the border of two water level areas
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| ** Weirs
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| ** Culverts
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| ** Pumps
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| ** Sewer overflows; if chosen to automatically generate the sewer areas, the sewer overflows can also be automatically generated
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| <br>'''Step 3'''
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| Adjust, if needed, the hydrological coefficents used for the calculations for the [[Terrain#Surface|surface terrain]], the [[Terrain#Underground|underground terrain]] and the [[Functions#Function_values|function values]] (for example the amount of water storage for a certain type of building).
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| <br>'''Step 4'''
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| The water system can be made visable with panels and a network visualization.
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| <br>'''Step 5'''
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| In step 5 you have to choose the result types (the different results which can be exported) you want to see after the calculation is done. Some overlays require a threshold value. Read below for the different result types to choose from and the threshold values. One of the overlays can be selected as the first overlay, which then will be visible as the parent Overlay. You can always later adjust the result types you want to see and calculate the Overlay again.
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| Also you can set the number of timeframes in the slider. The timeframes are the intermediate results of the calculation and are not the same as the timesteps. Each timeframe contains numerous timesteps, based on the grid cell size and the speed of the flooding (see for more information the [[Flooding_(Overlay)#Flooding_Model|Courant number]]). The more timeframes you choose, the more insight you will get into the calculation. Each of the timeframe results can be exported.
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| <br>'''Step 6'''
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| In the last step, some additional result types can be chosen to be visualized. Thes overlays contain input data that is used for the calculation, for example the manning value.
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| ==Result types==
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| Each Water Overlay is a [[grid overlay]] showing results on the surface (flooding), sub-surface (groundwater), open water and sewer system. The following results are produced:
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| {| class="wikitable" | | {| class="wikitable" |
| ! Result type
| | |[[File:Overlay_rainfall.png]] |
| ! Unit
| | |[[Rainfall_(Overlay)|Rainfall Overlay]] |
| ! Description
| | |provides insight into the water stress and impact caused by (excessive) rainfall |
| |- | |
| |BASE_TYPES | |
| |nominal value | |
| |Division of gridcells in water, land, water level areas, sewer areas that are connected to the sewer, breach areas and hydrological constructions | |
| |-f
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| |CHLORIDE
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| |
| |
| |
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| |-
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| |DIRECTION
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| |Degrees
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| |The direction of the flooding
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| |-
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| |EVAPORATED
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| |m (mm)¹
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| |The amount of water that is evaporated
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| |-
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| |GPU OVERVIEW
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| |
| |
| |
| |
| |-
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| |IMPACTED_BUILDINGS
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| |nominal value
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| |Constructions impacted by flood: the value from the function value indicator is assigned to a building if the water depth at a grid-cell surrounding the building exceeds the overlay attribute value IMPACT_FLOOD_TRESHOLD_M
| |
| |-
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| |LAST SPEED
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| |m/s
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| |The speed of the flooding at the last calculated timestep
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| |- | | |- |
| |MAX SPEED | | |[[File:Overlay_flooding.png]] |
| |m/s | | |[[Flooding_(Overlay)|Flooding Overlay]] |
| |The maximum speed of the flooding of all the calculated timesteps | | |provides insight into water stress and impact caused by breaches in levees or other sources causing excessive water inflow |
| |- | | |- |
| |NITROGEN | | ||[[File:Overlay_groundwater.png]] |
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| | |[[Groundwater_(Overlay)|Groundwater Overlay]] |
| |
| | |provides insight into long-term processes of water flow both on the surface and underground |
| |-
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| |PHOSPHORUS
| |
| | | |
| | | |
| |-
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| |SEWER_LAST_VALUE
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| |m (mm)¹
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| |The amount of water in the sewer storage at the last calculated timestep | |
| |- | |
| |SEWER_MAX_VALUE
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| |m (mm)¹
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| |The maximum amount of water in the sewer storage of all the calculated timesteps
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| |-
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| |SURFACE_DURATION
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| |s (min)¹
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| |The amount of time the water depth in a cell exceeds the value set in the overlay attribute value SHOW_DURATION_FLOOD_LEVEL_M
| |
| |-
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| |SURFACE_FLOW
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| |m3/m2
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| |Total volume of water passed a grid-cell, scaled by the cell surface (grid cell-size^2)
| |
| |-
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| |SURFACE_LAST_VALUE
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| |m (mm)¹
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| |The water depth at the last calculated timestep
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| |-
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| |SURFACE_MAX_VALUE
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| |m (mm)¹
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| |The maximum water depth of all the calculated timesteps
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| |-
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| |UNDERGROUND_FLOW
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| |m³/m²
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| |Total infiltration amount from the surface to groundwater
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| |-
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| |UNDERGROUND_LAST_STORAGE
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| |-
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| |UNDERGROUND_LAST_VALUE
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| |m (mm)¹
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| |The amount by which the groundwater table has risen above the initial groundwater level at the last calculated timestep
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| |-
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| |UNDERGROUND_MAX_STORAGE
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| |
| |
| |
| |
| |-
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| |UNDERGROUND_MAX_VALUE
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| |m (mm)¹
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| |The maximum amount by which the groundwater table has risen above the initial groundwater of all the calculated timesteps
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| |-
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| |UNDERGROUND WATERTABLE
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| |
| |
| |
| |
| |-
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| |WATER_STRESS
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| |m (mm)¹
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| |The maximum water depth during the simulation (almost the same as the SURFACE_MAX_VALUE, but at the terrain type water only a water depth is shown if the depth exceeds the overlay attribute value ALLOWED_WATER_INCREASE_M)
| |
| | |
| |} | | |} |
| | <!--==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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| ¹ the units between () are as displayed in the 3D client. If exported to GTiff the SI-convention is used: meters (m) and seconds (s).
| | 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. |
| | |
| ==General Tab==
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| [[File:General_tab.JPG|250px|right|The geberal tab of the Water Overlays.]]
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| The General Tab can be found at the panel on the right side, when selecting a Water Overlay. In this tab several settings can be adjusted.
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|
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| ===Calculation Preference===
| | ;[[Hydrologic_features_(Water_Overlay)|Hydrological features]] |
| Here you can manipulate the computation time step by choosing between the option SPEED, AVERAGE and ACCURACY. The computational timesteps will be set according to the Courant criterion:
| | :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]] |
| | :See [[Hydraulic structures (Water Overlay)|Hydraulic structures]] for the list of supported structures. |
| | ;[[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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| Δt = Δx /u<sub>max</sub>
| | ==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]]; |
| | --> |
|
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|
| where:
| | ==Results== |
| * Δt = computational timestep
| | 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]]. |
| * Δx = grid cell size
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| * u<sub>max</sub> = max velocity, assumed 2.5 (SPEED), 5 (AVERAGE) and 10 (ACCURACY) m3/s respectively
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| ===Grid cell size=== | | ==How-to's== |
| The {{software}} computes flow equations over a rectangular cartesian grid, the grid cell size can be set by clicking on Change Grid.
| | * [[How to add and remove an Overlay]] |
| After the grid cell size is changed, the Overlay is immediately being recalculated.
| | * [[How to manually configure a Water Overlay|Configure a Water Overlay]] |
| Note: if you choose a smaller grid cell size, both the amount of time steps (see Calculation Preference) and amount of computational cells increase.
| | * [[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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| ===Refresh Grid=== | | ===Features and components=== |
| By Refreshing the grid, the Overlay is recalculated. This may take some time, depending on the grid cell size, the size of your project and the calcualtion preference.
| | * [[Hydrological features (Water Overlay)|Hydrological features]] |
| Below some use cases when to use Refresh Grid:
| | * [[Hydraulic structures (Water Overlay)|Hydraulic structures]] |
| * when you have changed a setting in the Configuration Wizard, but not clicked on the Finish button of the wizard. | | * [[How to_manually_configure_a_Water_Overlay|Manual configuration Options]] |
| * when you change the Result type or calculcation preference in the General tab
| | * [[Simulation data (Water Overlay)|Simulation data]] |
| * when you change the legend in the Legend tab
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| * when you change the keys in the Keys tab | |
| * when you change the attrbutes of the Overlay in the Attributes tab | |
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| ===Export Grid File=== | | ===Attributes=== |
| You can export the current result type as either a GeoTiff (binary file/bitmap image can be opened in a GIS or in an image viewer) or ASCII (text file, can also be opened in a GIS but is also readable in a text editor) file.
| | * [[Model attributes (Water Overlay)|Water Module Attributes]] |
| Also, it is possible to export the difference result type of the current and maquette situation.
| | * [[Hydrological attributes of buildings (Water Overlay)|Hydrological Attributes of Buildings]] |
| | * [[Hydrological attributes of terrains (Water Overlay)|Hydrological Attributes of Terrains]] |
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| ===Save Overlay result===
| | {{WaterOverlay output nav}} |
| With this option you can create a duplicate inactive copy of the current overlay. This is noticeable in the Overlays panel on the left side of the screen. The duplicated overlay will have (inactive copy) behind the overlay name and is greyed out. This copy is not being recalculated when changing settings in the original duplicated overlay. When checking the checkbox: active in simulation, the copy becomes active again and can be recalculated. Also the overlay name is again in black and not grayed out anymore.
| | {{Overlay nav}} |
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| ===Show Water Balance===
| | [[Category:Water Module]][[Category:Overlays with result types]] |
| The Water Balance panel shows the in- and outflow of water in m3. The Water Balance panel is also visible when clicking on the Debug info (see below).
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| The water balance is made up of the following components (dependent on what is in the project):
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| * Land surface: amount of water on the land surface after simulation (m3)
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| * Water surface: amount of water stored on water cells after simulation (m3)
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| * Building storage: amount of water stored in building storage (m3)
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| * Sewer storage: amount of water stored in sewers after simulation (m3)
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| * Underground storage: amount of water stored in the sub-soil after simulation (m3)
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| * Evaporated: amount of water evaporated after simulation (m3)
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| * Outlet: amount of water extracted from the model during the simulation via outlets of water areas or sewer pumps (m3).
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| ===Warnings===
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| When the grid cell size is too large in combination with the project size, a warning pops up. This means that calculated results are not accurate. The solution to this is to change the grid cell size to a smaller number.
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| ===Debug Info===
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| The debug info contains the following information:
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| * Rain: the amount of rainfall (mm) in the duration of the rainfall event (hours)
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| * Total Simulation: the simulation period (hours)
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| * Cells: The dimensions of the simulation: the amount of computational cells and the amount of time steps (cycles)
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| * Water areas:
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| * Weir flow: the amount of water flown over weirs during simulation (m3)
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| * Sewer overflow: the amount of water flown over sewer overflows during simulation (m3)
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| * GPU time: the computation time on GPU (seconds)
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| * Volume: total volume of the in- and outflow of water in the model.
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| If you click on the Debug Infom the Water Balance panel pops up.
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| ==Keys tab==
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| The tab Keys refers to the settings for the water system (areas and constructions) that are adjusted by following the configuration wizard in the General tab. It is therefore generally not needed to change the keys in this tab, as this can be done also in the configuration wizard. However, below an explanation of the Keys for areas and buildings.
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| | |
| {| class="wikitable"
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| ! Attribute
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| ! Unit
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| ! Description
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| |-
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| |Water Level
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| |m + datum
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| |initial water level, relative to datum, for all water cells in a water area
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| |-
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| |Outlet
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| |m3/s
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| |water abstraction for all water cells in a water area
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| |-
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| |Outlet level
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| |m + datum
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| |initial water level, relative to datum, for all water cells in an outlet area (breach for example)
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| |-
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| |Outlet capacity
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| |m3
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| |maximum amount of water that can be used for the outlet
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| |-
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| |Sewer Storage
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| |m
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| |available storage in sewers at the start of simulation in a sewer area
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| |-
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| |Sewer Pump Speed
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| |m3/s
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| |sewer water abstraction for all cells in a sewer area
| |
| |}
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| Keys referring to constructions (building attributes)
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| {| class="wikitable"
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| ! Attribute
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| ! Unit
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| ! Description
| |
| |-
| |
| |Weir Height
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| |m + datum
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| |weir crest level
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| |-
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| |Weir Output
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| |m3/s
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| |The amount of water that flows through a weir/culvert
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| |-
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| |Weir Coefficient
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| |
| |
| |linear weir coefficient for accounting discharge & contraction losses
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| |-
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| |Culvert Speed
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| |m3/s
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| |the discharge capacity of a culvert
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| |-
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| |Pump Speed
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| |m3/s
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| |the capacity of a pump
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| |-
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| |Sewer Overflow Height
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| |m + datum
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| |the height of a crest of a sewer overflow
| |
| |-
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| |Sewer Overflow Speed
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| |m3/s
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| |the discharge capacity of a sewer overflow
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| |-
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| |Chloride
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| |mg/m2
| |
| |
| |
| |-
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| |Nitrogen
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| |mg/m2
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| |
| |
| |-
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| |Phosphorus
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| |mg/m2
| |
| |
| |
| |-
| |
| |}
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| ==Attributes tab==
| |
| This tab shows the attributes of result types that can be adjusted. These attributes can also be adjusted in the configuration wizard in step 5 in the General tab. It is therefore generally not needed to change the attributes here. However, below an overview of the Overlay Attributes.
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| | |
| {| class="wikitable"
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| ! Attribute
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| ! Unit
| |
| ! Description
| |
| |-
| |
| |ALLOWED_WATER_INCREASE_M
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| |m
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| |increment by which the water level on a water cell is allowed to increase before the depth is shown in the WATER_STRESS result type
| |
| |-
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| |AVG_SURFACE_WATER
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| |
| |
| |
| |
| |-
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| |DESGIN_FLOOD_ELEVATION_M
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| |m
| |
| |
| |
| |-
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| |GROUND_BOTTOM_DISTANCE_M
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| |m
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| |
| |
| |-
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| |GROUND_WATER
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| |
| |
| |
| |
| |-
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| |IMPACT_FLOOD_THRESHOLD_M
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| |m
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| |maximum waterdepth around a building where after the building is assumed impacted shown in the IMPACTED_BUILDINGS result type
| |
| |-
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| |MAX_SPEED_MS
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| |
| |
| |
| |
| |-
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| |MIN_SLOPE
| |
| |
| |
| |slope whereunder the pressure slope is assumed 0
| |
| |-
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| |SEWER_OVERFLOW_THRESHOLD
| |
| |
| |
| |fraction of storage whereafter sewer overflows take place
| |
| |-
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| |SHOW_DURATION_FLOOD_LEVEL_M
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| |m
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| |threshold value of the amount of water on a grid cell that is used for the SURFACE_DURATION result type
| |
| |-
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| |SUPERGRID
| |
| |
| |
| |
| |
| |-
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| |SURFACE_WATER_EVAPORATION_FACTOR
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| |
| |
| |
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| |-
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| |TIMEFRAMES
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| |
| |
| |the number of intermediate (overlay) results you would like to see of the calculation. A timeframe is not the same as a timestep. A timeframe is an intermediate (overlay) result and can contain already a number of timesteps. The number of timesteps is based on the grid cell size and the speed of the flooding (see for more information the [[Flooding_(Overlay)#Flooding_Model|Courant number]]).
| |
| |}
| |
