How to configure the Water Overlays

Please note: This page is currently being updated.

This page describes several use cases and examples of configurations in the Flooding Overlay.

Simulate a levee breach scenario 1

In this scenario we want to simulate a levee breach near an adjacent waterbody. In this example, the whole waterbody is present in the 3D project. This is important to notice, to model the correct volume of the waterbody. If your waterbody is too large or your project is smaller, you can model the breach area differently, see therefore the use case below. In this scenario you would want to have the breach connected to the water body, since we are going to use the water level of the waterbody to determine the flooding.

In the steps here, the breach area is drawn in the Editor. It is also possible to import a GeoJSON file with the location of the breach.

How to set-up the breach area:

1. In the Editor go to GEO Data --> Areas
2. Add a new area by clicking in the bottom left corner.
3. Select the newly created area (named Area) and give it a fitting name on the right
4. Zoom in to the location where you want to have the breach and click on the Adjust area button
5. Select the location of your breach and click on Apply settings. Make sure the breach is connected to the water body.
6. Go to the tab attributes and set the breach floor attribute by adding the attribute name, value and clicking on save.

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How to configure the flooding:

1. Add a Flooding Overlay and go to the Configuration Wizard of the Flooding Overlay.
2. In step 2.1 select the attribute that specifies your breach floor so the software knows which area is your breach area.
3. Click on Next.
4. In the dropdown menu choose the name of your breach area and check if the attributes correspond with what you have set as attributes or change them here.
5. In step 2.2 import your water level areas with at least a water level attribute.
6. Finish the Wizard and refresh the Overlay.
7. After the flooding is calculated, check the Water Balance to get more insight in your scenario.

Simulate a levee breach scenario 2

In this scenario we want to simulate a levee breach near an adjacent water body, but in this case, the water body is not fully in 3D in the project. For example, if your project is of a part of Flevoland and you don't want to create a project of the whole IJsselmeer, you can simulate the flooding by the IJsselmeer. In this scenario you would not want to have the breach connected to the water body, since we are not going to import the water level of this water body. This means the water body will not have a water level and thus the flooding will go to the lowest point which is probably to the water body and not the land.

In the steps here, the breach area is drawn in the Editor. It is also possible to import a GeoJSON file with the location of the breach.

How to set-up the breach area:

1. In the Editor go to GEO Data --> Areas
2. Add a new area by clicking in the bottom left corner.
3. Select the newly created area (named Area) and give it a fitting name on the right
4. Zoom in to the location where you want to have the breach and click on the Adjust area button
5. Select the location of your breach and click on Apply settings. Make sure the breach is not connected to the water body and ideally draw it on the inside of the dike.
6. Go to the tab attributes and add the breach floor attribute and the outlet capacity. The outlet capacity is the volume of the waterbody. Also add either the outlet Q or the outlet level to determine how much water will flow through the breach.

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How to configure the flooding:

1. Then follow the steps above to configure the flooding.
2. In step 2.2 when you import the water level areas, don't import the water level area for the large water body near your breach area.
3. Finish the Wizard and refresh the Overlay.
4. After the flooding is calculated, check the Water Balance to get more insight in your scenario.

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Time-controlled flow rate in a breach area

To create a variable Outlet Q in a breach area, a CSV (comma-separated values) file can be imported. Below the steps on how to create such a breach area. For this example we create the CSV in Excel, but you can also use another program to create the CSV.

How to set-up your CSV in Excel:

1. Open Excel.
2. In the first column, define your time steps. This can be in seconds, minutes, hours or days.
3. Add the corresponding flow rates per step in the second column.
4. Save the Excel as a CSV.

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How to import the CSV as the flow rate:

1. Either add a breach area or have your GeoJSON file with your breach area ready. The area should have at least a breach floor attribute.
2. Add a Flooding Overlay.
3. Go to the Configuration Wizard of the Flooding Overlay.
4. In step 2.1 either select the attribute that specifies your breach floor or import your GeoJSON file.
5. Click on Next.
6. In the dropdown menu, select your breach area. Now click on Edit.
7. Import your CSV file by selecting the CSV file.
8. Select the time units in your file.
9. Select the seperator for your file.
10. Click on Apply.

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Multi breach simulation

It is also possible to simulate a situation in where there is first one levee breach, following by another (or multiple). Therefore we also make use of the variable Outlet Q and a CSV file as mentioned above in the previous use case. In the steps below, two breaches are demonstrated, but the same steps apply to multiple breaches.

How to set up a multi breach scenario:

1. First create a CSV file in where you structure the data in a way that at the start of the simulation, the outlet is 0. See for an example the image below.
2. Either add two breach areas or have your GeoJSON file with your breach areas ready. The areas should have at least a breach floor attribute.
3. Add a Flooding Overlay.
4. Go to the Configuration Wizard of the Flooding Overlay.
5. In step 2.1 either select the attribute that specifies your breach floor or import your GeoJSON file.
6. Click on Next.
7. In the dropdown menu, select the breach area that breaks second.
8. Click on Edit and import the CSV file.
9. Finish the Wizard and refresh the Overlay.

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Import waterdepth data

For modelling the correct volume of a waterbody, it is important that the depth of a waterbody is accurately modelled. If you have data of your waterbodies and their depth, for example sections of water bodies, it is possible to import this data as part of the DEM (Digital Elevation Model). Together with importing your water level areas, the volume of the waterbody can then be more accurately calculated. Below the steps on how to import the data.

The steps below assume you have already a digital dataset of your waterdepth data available (thus no PDF's with sections). Either a vector dataset of the waterbodies with an attribute that shows the depth or a raster dataset of the waterdepth data is sufficient to ues. The steps below describe how to use the vector dataset with the depth of the soil of the waterbodies. For this use case, the use of a GIS is needed to transform the vector data to a (partial covering) raster dataset to import in the Tygron Platform. In this example, we use QGIS.

How to create the raster dataset:

1. Open the vector dataset in a GIS. In this case we use a shapefile of the waterbodies (polygons) with the waterdepth as attribute of these polygons.
2. Now we want to create the raster by making use of the rasterize menu. This menu can be found in the tab Raster > conversion > rasterize (vector to raster)
3. Define in the panel the shapefile, the output raster and either the raster size or resolution.
4. When these settings have been set, click on the pencil icon to edit the text. Add the following statement to the text box: -a_nodata 0 (see image). This means that 0 depicts the no data value in the raster. This will create a raster dataset with only values for the depth where there is a waterbody and no data values where there is no waterbody. When importing this into the Tygron Platform, on the places where there is nodata, the Tygron Platform will use the values from the default heightmap created with open data.
5. Click on OK and wait till the raster data is created. Now you can close the GIS program.

Simulate a flood wave with in- and outlet areas

To simulate a scenario of for example a flood wave in a river, you can create in- and outlet areas. These are basically breach areas. The inlet area demonstrates the inflow of water, the outlet area demonstrates the outflow of water. The images show an example with invented values for the attributes.

How to set up a flood wave scenario:

1. Draw two areas at the one side of the river where water will flow in and at the other side of the river where the water flows out. It is also possible to import a GeoJSON file with these areas.
2. The areas should have a breach floor attribute. Give the inlet area an outlet level and/or outlet Q. This depends on the data you have of the scenario. If you know for example the water level of a flood wave, use the outlet level. If you know the flow rate, use the outlet Q. Both is also possible, then the outlet level has precedence over the outlet Q. For the outlet area, enter, a negative outlet Q value and/or an outlet level.
3. Add a Flooding Overlay and go to the Configuration Wizard of the Flooding Overlay.
4. In step 2.1 either select the attribute that specifies your breach floor or import your GeoJSON file.
5. Click on Next.
6. In the dropdown menu, check if the attributes of the areas correspond with what you have set as attributes.
7. In step 2.2 import your water level areas with at least a water level attribute.
8. Finish the Wizard and refresh the Overlay.
9. After the flooding is calculated, check Water Balance to get more insight in the scenario.

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Track flow in a hydrological system

To track water in a hydrological system, i.e. find where water from a specific point flows to, it is possible to artificially add a chemical emitter in the water system. Any water passing through that construction will pick up the chemical. By having a result type added which highlights that chemical, the flow of the water can be tracked quite accurately.

For the purposes of this scenario, a simple hydrological model will be assumed, although the same technique can be used for breaches and other calamitous scenarios. We will also assume we can use the CHLORIDE particle as our "tracker". We will track any water flowing in from outside the system through a specific inlet.

How to set up water flow tracking:

1. Configure a base hydrological system. For the specified scenario, use the groundwater overlay.
2. Ensure the hydrological system has at least one inlet configured to simulate flow into the hydrological system.
3. Also ensure the hydrological system has a CHLORIDE result type, either as main result or as a child result type.
4. Find the inlet, the water of which you want to track, in the 3D world.
5. Add the "CHLORIDE" attribute to the inlet, with a value of "1".
6. Ensure the overlay is recalculated.
7. Inspect the "Chloride" result overlay. The greater the concentration of chloride in any given location, the more water from the inlet has flowed there.

To track water from different sources (different inlets, or other hydrological constructons), add the attribute to the construction of which you wish to track the water.

To track water from different sources collectively, each source can be configured with the same chemical attribute. (In the specified example, multiple sources can be provided with the CHLORIDE attribute.)

To track water from different sources with the ability to differentiate between what water came from which specific source, each source can be given a different chemical to produce.