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| {{learned|what the rainfall overlay is|how the rainfall overlay can be used|how the rainfall overlay can be configured|what principles govern its calculation|what formulas are used to perform the calculations}}
| | [[File:Rainfall-Overlay.jpg|thumb|right|200px|Rainfall overlay]] |
| | The Rainfall Overlay is a variant of the [[Water Overlay]], which in turn is a [[Grid overlay|grid overlay]]. Water overlays are connected to the [[Water Module]], a complex hydrological calculation module within the {{software}}. |
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| ==What is the rainfall overlay==
| | The Rainfall overlay specializes in displaying the hazard and impact of (heavy) rainfall over the project area. Based on the elevation model, terrain roughness and representations of the sewer and water systems, several result types can be generated by the accompanying Water Module. |
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| The rainfall overlay is a [[grid overlay]], which calculates where and how water would flow in situations where severe rainfall takes place. It does so by simulating water falling onto the [[3D world]] over the course of thousands of steps. During each step, water can, among other things, land on the ground, flow over the surface, infiltrate into the ground, flow underground, and end up in surface water.
| | A [[Rainfall_Overlay_tutorial|Rainfall Overlay Tutorial]] is available to get you started with this overlay. |
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| By repeating these simulation steps thousands of times, the influx and flows of water are accurately approximated.
| | In order to get more familiar with the different components of the Rainfall Overlay check out Quadrant 2 of the [[Testbed_water_module|Water Module Testbed]]. This Testbed is available to you as a project in the {{software}}. |
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| ==What can the rainfall overlay be used for== | | ==Rainfall overlay results== |
| The rainfall overlay is currently fit for simulating the flow and effects of severe rainfall on flat or mildly hilly areas, for map sizes of up to 5km. Larger maps, or calculations which involve an impulse of water such as levee breaches are not yet recommended. | | The Rainfall Overlay is a Water Overlay that is connected to the Water Module. This Water Module performs two dimensional grid based water simulations for a large set of input data and parameters, configured mostly through a related [[Water Overlay Wizard]]. When a simulation finishes, the module stores the result in the Rainfall overlay based on the selected result type. Only one result type can be stored per Rainfall overlay. |
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| The overlay can be configured to display various results of the simulated rainfall. For example it is possible to see the maximum amount of water certain locations had to endure, or the amount of water which has flowed across certain locations. | | The Water Module however, is not restricted to generating only one type of result. Instead it can produce multiple unique result types for one single simulation. |
| | Fortunately it is possible to add additional result type overlays which relate to a particular Rainfall overlay. These are known as [[Result Child Overlay]]s. Again, each child overlay only stores one particular result type. |
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| ===Output types===
| | Apart from multiple result types, the Rainfall overlay can also store result data of multiple, intermediate simulation results, instead of just a single end result. These intermediate simulation results are known as [[timeframes (Water Overlay)|timeframes]]. |
| * '''WATER_STRESS''': The maximum amount of excess water at any time during the simulation. Differs from SURFACE_MAX_VALUE because water stored on bodies of water are not immediately deemed "excess".
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| * '''SURFACE_LAST_VALUE''': The amount of water remaining on the surface after the simulation is over
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| * '''SURFACE_MAX_VALUE''': The largest amount of water that was on the surface at any time during the simulation. Differs from WATER_STRESS in that water stored on bodies of water is included.
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| * '''SURFACE_FLOW''': The total amount of water which has flowed across the surface
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| * '''SURFACE_DURATION''': The total amount of time the surface has water on it
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| * '''SEWER_LAST_VALUE''': The amount of water remaining in the sewer after the simulation is over
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| * '''SEWER_MAX_VALUE''': The largest amount of water that was in the sewer at any time during the simulation
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| * '''UNDERGROUND_FLOW''': The total amount of water which has flowed underground
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| ==Adding and removing the overlay==
| | For the full list of result types, see [[Result type (Water Overlay)#List of Result Types|List of Result Types]]. |
| The overlay can be added to the project multiple times, to present different outcomes or different scenarios. For information on adding and removing the overlay to and from the [[project]], see the page on [[overlay#Adding and removing overlays|overlay]]s in general.
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| ==Configuring the overlay==
| | For other results, which are not overlay results, but still related to the simulation for a particular Rainfall overlay, see [[Results (Water Overlay)|Rainfall overlay results]]. |
| Accompanying the inherent complexity of the overlay is the ability to add additional data and adjust various values to change or enhance the way it calculates. The overlay itself contains a number of attributes which can be configured. Attributes in other parts of the project, such as the connected [[weather|rain definition]], buildings, terrains, and areas defining water level areas.
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| ===Data required=== | | ==Module== |
| No data is explicitly required. The overlay is designed to provide initial calculations based on default values and minimal assumptions. However, the model can be refined with your own data. The following data can be prepared and uploaded in [[geojson]] format:
| | A Rainfall Overlay can be configured by opening the Rainfall Overlay Wizard. More in-depth information can be found under each of the categories below. |
| | {{Water Module buttons}} |
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| ====Water level areas==== | | ==References== |
| For defining "level areas" with a set water level. This file is loaded in as [[area]]s.
| | # [[Water Module Theory#Formulas|Water model formulas]] |
| {| class="wikitable"
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| ! Attribute
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| ! Description
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| ! Example
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| ! Remark
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| |-
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| | NAME
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| | The name of the water level area.
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| | PG 256
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| | This attribute is not loaded in as attribute, but can be used as name to identify the resulting area in the Engine later on.
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| |-
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| | WATER_LEVEL
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| | The height of the water, in meters, measured from Amsterdam Ordnance Datum (mNAP).
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| | 1.6
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| | For a water level area with infinite storage, this can be set to an extreme negative number (e.g. -9999). However, note that this would also place this area far below level areas with a proper height set.
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| |-
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| | OUTLET
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| | The amount of water which disappears from this level area in cubic meters per second (m3/s).
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| | 0.007
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| |}
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| If no water levels exist, a virtual water level area is assumed which covers the entire [[3D world]], with no OUTLET value and a WATER_LEVEL of -1000.
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| ====Sewers====
| | {{WaterOverlay output nav}} |
| For defining "sewers" which allow for water storage. This file is loaded in as [[area]]s.
| | {{Overlay nav}} |
| {| class="wikitable" | |
| ! Attribute
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| ! Description
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| ! Example
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| ! Remark
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| |-
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| | NAME
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| | The name of the sewer.
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| | Sewer North-East
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| | This attribute is not loaded in as attribute, but can be used as name to identify the resulting area in the Engine later on.
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| |-
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| | SEWER_PUMP_SPEED
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| | The speed at which water is pumped out of the sewer, in cubic meters per hour (m3/h).
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| | 1
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| | All areas which are not plots of this kind should either not have PERCEEL as an attribute, or should have it set to 0.
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| |-
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| | SEWER_STORAGE
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| | The amount of water which can be stored in this sewer, in meters (m).
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| | 0.007
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| | The total amount of storage for this sewer is the surface area of the polygon representing this sewer, times this attribute.
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| |}
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| If no sewers exist, the model has no water flowing into sewer containers for storage.
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| It's possible to generate sewers automatically, using the " Create Sewer Areas" function in the editor:
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| {{Editor ribbon|header=3D World|bar=Areas|dropdown=Create Sewer Areas}} | |
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| ====Weirs====
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| For defining connections between level areas. This file is loaded in as [[construction]]s.
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| {| class="wikitable"
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| ! Attribute
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| ! Description
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| ! Example
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| ! Remark
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| | NAME
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| | The name of the weir.
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| | PG 256
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| | This attribute is not loaded in as attribute, but can be used as name to identify the resulting contruction in the Engine later on.
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| |-
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| | WEIR_HEIGHT_M
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| | The height of the weir, in meters, measured from Amsterdam Ordnance Datum (mNAP).
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| | 1.8
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| | When using this model outside of the Netherlands, the height is in the same scale as the [[Terrain height]] of the project. When an extreme negative value is used, the construction acts like a culvert.
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| |-
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| | WEIR_SPEED
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| | The speed at which water is moved from one level area to the other, in cubic meters per second (m3/s).
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| | 0.007
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| | Once the water level exceeds the height of the weir, the water flows at this constant speed until the water level no longer exceeds the height of the weir.
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| |-
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| | WATEROUTLET
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| | The speed at which this construction also functions as a water outlet, in cubic meters per second (m3/s).
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| | 0.005
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| | This is in addition, and takes precedence, over the water pumped out at WEIR_SPEED.
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| |}
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| If no weirs exist, there are no connections between water level areas and water is not transferred between them.
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| Weirs must overlap with at most 2 water level areas. If a weir overlaps with more that 2 water level areas, 2 areas are selected at random which the weir pumps between. If a weir overlaps with only 1 water level area, only its outlet function is processed. Weirs which do not overlap with any water level areas have no effect.
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| ====Warnings====
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The Rainfall Overlay is a variant of the Water Overlay, which in turn is a grid overlay. Water overlays are connected to the Water Module, a complex hydrological calculation module within the Tygron Platform.
The Rainfall overlay specializes in displaying the hazard and impact of (heavy) rainfall over the project area. Based on the elevation model, terrain roughness and representations of the sewer and water systems, several result types can be generated by the accompanying Water Module.
A Rainfall Overlay Tutorial is available to get you started with this overlay.
In order to get more familiar with the different components of the Rainfall Overlay check out Quadrant 2 of the Water Module Testbed. This Testbed is available to you as a project in the Tygron Platform.
Rainfall overlay results
The Rainfall Overlay is a Water Overlay that is connected to the Water Module. This Water Module performs two dimensional grid based water simulations for a large set of input data and parameters, configured mostly through a related Water Overlay Wizard. When a simulation finishes, the module stores the result in the Rainfall overlay based on the selected result type. Only one result type can be stored per Rainfall overlay.
The Water Module however, is not restricted to generating only one type of result. Instead it can produce multiple unique result types for one single simulation.
Fortunately it is possible to add additional result type overlays which relate to a particular Rainfall overlay. These are known as Result Child Overlays. Again, each child overlay only stores one particular result type.
Apart from multiple result types, the Rainfall overlay can also store result data of multiple, intermediate simulation results, instead of just a single end result. These intermediate simulation results are known as timeframes.
For the full list of result types, see List of Result Types.
For other results, which are not overlay results, but still related to the simulation for a particular Rainfall overlay, see Rainfall overlay results.
Module
A Rainfall Overlay can be configured by opening the Rainfall Overlay Wizard. More in-depth information can be found under each of the categories below.
References
- Water model formulas
