Simulate a flood

Note:

This tutorial continues the workflow of Set up a flood simulation. It's not necessary to have completed that tutorial before starting this one, but doing so will give you context about the data used to perform the flood simulation and how you can simulate a flood using your own data and area of interest.

In 2024, the United States experienced 27 weather- and climate-related events that resulted in damage of more than $1 billion each to affected communities and their infrastructure. Severe rainfall and flooding events make up a significant portion of these costs, with Hurricane Helene alone causing $79.6 billion in damage to the southeastern United States. Understanding and preparing for flooding caused by these extreme weather events has become a critical need for communities.

In this two-part tutorial series, you'll use ArcGIS Pro to perform a sophisticated flood simulation for a hypothetical high rainfall event in Houston, Texas. By analyzing the results alongside structure and road data, it's possible to predict how infrastructure might be impacted by such an event.

In this tutorial, the second in the series, you'll use the prepared data to perform the simulation. Then, you'll export the results as a flood depth raster, which you'll compare to buildings and roads data to determine how much infrastructure might be impacted by the flood event. You'll also configure flood depth charts to quickly view the impacts at different flood levels.

This tutorial was last tested on April 8, 2026, using ArcGIS Pro 3.6. If you're using a different version of ArcGIS Pro, you may encounter different functionality and results.

Requirements

• ArcGIS Pro Advanced (see options for software access)

Run the flood simulation

Using the input layers that were configured in the previous tutorial, you'll set the parameters for the flood simulation and run it.

Define the simulation extent

First, you'll download an ArcGIS Pro project package containing the data necessary to perform the flood simulation for the area of interest. Then, you'll define the simulation extent and create a simulation layer.

Note:

If you completed the tutorial Set up a flood simulation, you can use the project from that tutorial instead of downloading the project package for this tutorial.

1. Download the Houston Flood Simulation 2 project package.
2. Browse to the downloaded file and double-click it to open the project in ArcGIS Pro. If necessary, sign in using your licensed ArcGIS account.

   Note:

   If you don't have access to ArcGIS Pro or an ArcGIS organizational account, see options for software access.

   The project contains a 3D scene of downtown Houston, Texas, with layers necessary for simulating flooding.

   

   The following layers are included:

   • The Structures and Roads layers, which contain important infrastructure in the area.
   • The Model Boundary layer, which contains the boundary of the study area for the simulation.
   • The Maximum Infiltration raster layer, which contains the maximum infiltration values for the ground at each pixel. This layer was created based on land cover values.
   • The Infiltration Rates raster layer, which contains the infiltration rate values for the ground at each pixel. This layer was created based on soil hydrologic groups and impervious surface percentages.
   • The Surface Roughness raster layer, which contains the surface roughness coefficient values for the ground at each pixel. This layer was created based on land cover values.
   • The NLCD 2024 Fractional Impervious Surface, USA SSURGO Soil Hydrologic Group, and NLCD 2024 Land Cover layers, which were used to create the other raster layers. All of these layers were clipped to the study area from ArcGIS Living Atlas of the World layers.
   • The WorldElevation3D/Terrain3D layer, which contains elevation data.
   • The four Environment layers, which make up the basemap and are for visualization and context purposes only.

   Note:

   To learn more about these layers and their sources, see the tutorial Set up a flood simulation.

   Next, you'll start setting parameters for the flood simulation. First, you'll define its extent. You'll use the model boundary, which already defines the extent of the scene.

3. On the ribbon, click the Analysis tab. In the Workflows group, click the Simulation button.

   

   A menu appears, listing three types of simulations to choose from. The Default option creates a flood simulation layer with no preset water. The Rainfall option creates a flood simulation layer with heavy rainfall. The Water Source option creates a flood simulation layer with a water source in the center.

   The flood in your simulation will be caused by a heavy rainfall event, so you'll choose the appropriate option.

4. Choose Rainfall.

   

   A toolbar appears at the bottom of the scene with options for setting the simulation extent. You have the option to manually set the simulation extent either by choosing a center point and setting a distance or by sketching a rectangle. You already have a layer that contains your model boundary, so you'll use it to set the extent rather than creating one manually.

5. In the Contents pane, click the Model Boundary layer to select it.
6. On the simulation toolbar, click the Area from Selected Layer button.

   

   Note:

   The Area from Selected Layer button will not be available unless a layer is selected in the Contents pane.

   On the scene, handles appear on the four edges of the model boundary, with a rotation control in the center. You can use these handles and the control to modify the extent, but you don't need to do that in this case.

7. On the simulation toolbar, click the Create Simulation in Area button.

   

   A new simulation layer, Flood Layer 1, is added to the Contents pane. The Configure Simulation pane appears. This pane contains options for configuring your flood simulation.

Configure basic parameters

Next, you'll configure some basic parameters for the simulation, including its name and resolution.

1. In the Contents pane, click Flood Layer 1 to make its name editable. Rename it to Houston Flooding and press Enter.

   

   The name of the simulation layer will be used as a prefix for the file names of any flood rasters you export from the simulation.

   Next, you'll set the resolution, or cell size, of the simulation. Simulations with higher resolutions have more detail, but take longer to process.

2. On the ribbon, click the Simulation tab. In the Resolution group, click the Cell Size drop-down menu and confirm 4096 is chosen.

   

   The number 4096 refers to the number of cells the result layer will be divided into. Your study area has a size of 6,000 meters by 6,000 meters, so when divided into a 4096 x 4096 grid, each cell has a size of 1.465 meters per side. This value is automatically calculated and shown in the box next to the menu.

   Tip:

   To set a specific resolution, such as 1 meter, click the Maximum Fit button next to the drop-down menu to make the Cell Size box editable and type the value you want.

   You can also change the temporal resolution. This option determines the number of computations done per second of the simulation. When water moves faster, for instance when it moves over steep terrain, it's important to set the temporal resolution higher, as there will be more changes per second. For flat terrain, where water flows slowly, a low number of computations per second is acceptable. In this example, the terrain of Houston is relatively flat, so you'll use a low temporal resolution.

3. In the Resolution group, confirm Temporal is set to Low.

   

   The last resolution setting is the slider between Precise and Fast. This setting determines the relative fidelity of the terrain resolution used by the simulation. A more precise resolution provides the best results, but has a slightly longer processing time.

   Because your simulation covers a relatively small area, has a moderate cell size, and will have a short duration, the overall processing time will be relatively short, so you'll use a more precise resolution for better results.

4. In the Resolution group, drag the slider so it is next to Precise.

   

   The simulation's resolution settings have been configured.

Configure precipitation parameters

Next, you'll determine the precipitation rate for the high rainfall event that causes your simulated flood. To base this rainfall event on a realistic storm scenario for Houston, you'll use the NOAA Atlas 14 Precipitation Frequency Data Server (PFDS). This resource estimates storm rainfall and duration for different regions of the United States.

1. Go to the Atlas 14 PFDS interactive map for Texas.
2. Under Select location, for By address, type Houston and choose Houston, TX, USA.

   

   The map zooms to Houston.

   Tip:

   To find estimates for a more specific location, you can either search by latitude or longitude or drag the crosshairs on the map.

3. Under the map, scroll down to the Point Precipitation Frequency (PF) Estimates section.

   This section contains a table of precipitation frequency estimates (in inches) for the location on the map. The table is organized by the duration of the rainfall and the average recurrence interval in years, with higher recurrence intervals indicating rarer and more severe storms.

   For this tutorial, you'll simulate a flood with a 1-hour duration and a 10-year interval. This event represents a historic storm (one that happens once every 10 years) with a short but intense duration.

   

   Based on the table, the estimated precipitation rate for a rainfall event of this type is 3.22 inches (equal to 81.78 millimeters). You'll use this value (in millimeters) for your simulation.

4. Return to ArcGIS Pro. In the Configure Simulation pane, for Rainfall Rate, confirm Duration is set to 1:00:00 and change Rate to 82 mm.

   

   Note:

   If you chose a precipitation frequency estimate for a different duration, you would also need to change the Duration parameter to match.

   You have the option to simulate multiple phases of intensity over time, such as a gradually increasing or decreasing rainfall rate. To accomplish this, you can add more rows to the Rainfall Rate table, each with its own duration and rate. Rates can also be exported or imported as a .csv file with the format of Seconds, Rate, Units (for example, 3600, 82, mm). For this tutorial, you'll simulate a consistent intensity with only one phase.

Configure input layers

Next, you'll configure the input layers to use in the simulation. You'll use the layers that were created in the previous tutorial.

1. In the Configure Simulation pane, for Participating Layers, confirm Visible Layers is chosen.

   

   This parameter ensures that any 3D layers visible on the map will be used as obstructions to flooding. In this case, you want the structures to be used.

2. In the Contents pane, confirm the Structures layer is turned on (checked) and that the 3D structures are visible on the map.

   

   Tip:

   In addition to local 3D building features, like the ones used in this tutorial, you can also use 3D buildings from a hosted scene layer, such as a 3D basemap. These buildings will be treated the same as extruded polygons, multipatch features, or models by the simulation. The benefit of using local 3D building features is that you can later measure and visualize flood depth impacts for each structure; this is not possible with buildings from a hosted scene layer.

   You won't set the Starting Water Level parameter, which adds water to the simulation before the simulation starts. Your simulation will assume a dry state before the rainfall event.

   Next, you'll set the infiltration rasters. You've already created two infiltration rasters, one measuring infiltration rate and one measuring maximum infiltration.

3. In the Configure Simulation pane, for Infiltration Rate (units/hr), choose Infiltration Rates. Confirm the unit of measurement is set to mm.
4. For Maximum Infiltration, choose Maximum Infiltration. Confirm the unit of measurement is set to mm.

   

   Lastly, you'll set the surface roughness raster, which determines the level of obstruction of the terrain surface and the smoothness of surface water flow.

5. For Surface Roughness Value, choose Surface Roughness.

   

   The rest of the pane lists the dimensions of the simulation. You set these dimensions when you set the resolution parameters.

6. At the bottom of the Configure Simulation pane, click Apply.

   The parameters you set are applied. You're ready to run the flood simulation. Before you do, you'll save the project, just in case you run into any problems when running the simulation.

7. On the Quick Access Toolbar, click the Save Project button.

   

   Since this is a tutorial, you'll reduce the playback rate for the simulation so the simulation takes relatively little time to run. This parameter has no impact on the output layer, only on how quickly the display is updated while the simulation runs. The end state of the simulation will be the same regardless of this parameter.

8. On the ribbon, in the Playback group, change Rate to 1 fps.

   

   The overall speed of the simulation is determined by the following factors:

   • The size of the simulation area and its cell size, temporal resolution, and precision
   • The Duration parameter of the simulation
   • The playback rate
   • Your computer's hardware specifications and graphics card

   This simulation may take between 2 minutes and 5 minutes, depending on your computer's hardware.

   Note:

   If your simulation fails to run or takes a particularly long time to run, your computer may not meet the ArcGIS Pro system requirements.

9. In the Build group, click Run.

   

   The simulation runs. On the ribbon, in the Playback group, the current duration is displayed in the Current box. Once it reaches 1 hour (the duration you set for the simulation), the simulation is complete.

   After the simulation finishes, the scene shows the end state of the simulation: the flooding after 1 hour of the extreme rainfall event. The blue water depth surface shows relative flood intensity.

   

   The river deepened and its channels widened. Other low elevation areas had significant flooding, including both major and minor roadways. Some areas experienced fragmented flooding areas, whereas others, like the area on the eastern side of the model boundary, experienced more widespread flooding. These patterns indicate potential impacts such as road closures, reduced access for emergency services, and increased risk to nearby properties and infrastructure, particularly where flooding is deeper and more continuous.

   Tip:

   To view earlier parts of the simulation again, use the options in the Playback group on the ribbon. You can also increase the playback rate to view the simulation in more detail.

10. On the scene, click anywhere on the water surface.

    A pop-up appears with information about the water depth, speed, flow rate, and flow direction at the location you clicked.

    

11. Close the pop-up. Close the Configure Simulation pane.
12. Save the project.

You've configured the flood simulation parameters and run the simulation, which shows where flooding is likely to happen during an extreme rainfall event. Next, you'll explore the results of your simulation.

Explore the results

Now that you've run the flood simulation, you'll export its results to a multidimensional Cloud Raster Format (CRF) raster that you can use for further visualization and analysis. You'll symbolize the CRF file to see where the most severe flooding occurs and create a temporal profile to see how flooding changes over the course of the simulation.

Export the results

First, you'll export a CRF that contains the water depth in the simulation.

1. On the ribbon, on the Simulation tab, in the Export group, click Analysis Results.

   

   The Export Simulation pane appears.

2. Confirm Name Prefix is set to Houston Flooding. For Location, keep the default location (in your project's default folder).
3. For Vertical Units, choose Meter. Confirm Format is set to CRF.

   By default, the start time is the hour closest to your current time. You'll change it to 12:00 a.m. so the progressive time stamps are more easily interpreted. This change is more useful for longer flood simulations that span multiple hours, but it's a good practice to follow in general.

4. For Start Time, change the time to 12:00:00 AM.

   

   Note:

   The date in the Start Time parameter is your current date. You can leave the date unchanged; it does not need to match the date in the example image.

   Next, you'll choose which results from the simulation to export. There are four options: water depth, water absolute height, water velocity vector, and water speed. For this tutorial, you'll only use water depth, which you'll use to assess which structures and roads will be impacted by the flood.

5. For Water Levels, uncheck every option except Water Depth.

   

   By default, a 1-hour simulation is exported at an interval of every 5 minutes of the simulation. It's possible to change the interval if you want more or less detail in the results, but you'll use the default value for this workflow.

   You'll also leave Include the simulation initial state unchecked, which will remove the first time step of the simulation from the exported results. If you included a starting water level in your simulation, you would want to check this option, but since you didn't, there's no meaningful information in the first time step.

6. At the bottom of the pane, click Export.

   The simulation is exported to a CRF file. The process may take up to a minute. Once it completes, you'll add the CRF file to your scene from the Catalog pane.

7. Close the Export Simulation pane.
8. In the Contents pane, under Simulations, turn off the Houston Flooding layer.
9. On the ribbon, click the View tab. In the Windows group, click Catalog Pane.

   

   The Catalog pane appears. By default, your CRF file was exported to your project folder.

10. In the Catalog pane, expand Folders and expand Houston Flood Simulation 2.

    

11. Right-click Houston Flooding_WaterDepth.crf and choose Add To Current Map.

    The flood depth CRF file is added to the scene. It is displayed with a default black and white continuous color ramp, with lighter areas having higher water depth. By default, the CRF shows the earliest time slice, when flooding was at its lowest, so the raster is mostly black.

    

Symbolize the flood depth raster

It would be more intuitive if flooding was depicted with a blue color scheme to represent water. You'll import a layer file that you downloaded with the project to apply more meaningful symbology to the layer.

1. In the Contents pane, click the color ramp for Houston Flooding_WaterDepth.crf.

   

   The Symbology pane appears.

2. In the Symbology pane, click the options button and choose Import from layer file.

   

3. In the Import symbology window, under Project, expand Folders, Houston_Flood_Simulation_2 (or 1, if you're using the same project from the previous tutorial), and commondata.

   

   Files attached to a project package are included in the userdata folder.

4. Click the userdata folder. Click Flood Raster by Depth.lyrx to select it.

   

5. Click OK.

   The symbology of the layer file is applied to the flood depth raster. The Symbology pane updates to show the flood depth values for each color in the scheme:

   

   The values range from under 3 inches (0.0762 meters) to over 3 feet (0.9144 meters). The lowest class is set to a transparent color to focus attention on where flooding is more severe. These depth cutoffs are guided by the National Weather Service's Turn Around Don't Drown campaign, which advises citizens of the following dangers:

   • It takes only 6 inches of fast-moving flood water to knock over an adult.
   • It takes only 12 inches of rushing water to carry away most cars.
   • It takes only 2 feet of water to carry away SUVs and trucks.

   On the scene, you're still looking at the earliest time slice, when the rainfall event had only recently started, so there is barely any flooding. Because the CRF file is multidimensional, it contains data from several time steps in the simulation. You'll change the layer so the most recent time slice is displayed instead, showing the most extreme flooding.

6. In the Contents pane, confirm Houston Flooding_WaterDepth.crf is selected.
7. On the ribbon, click the Multidimensional tab.

   

   Note:

   The Multidimensional tab is contextual, meaning it only appears when a relevant layer is selected. If Houston Flooding_WaterDepth.crf is not selected in the Contents pane, the tab won't be available.

8. In the Current Display Slice group, for StdTime, choose the time slice that ends with 01:00:00.

   

9. In the Contents pane, turn off the Structures and Roads layers.

   The scene now shows the flooding at the end of the extreme rainfall event.

   

   The most severe flooding tends to occur around rivers and other water bodies, but there are some areas throughout the city where streets and neighborhoods receive significant flooding.

Create a temporal profile

Using the StdTime parameter on the Multidimensional tab, you can explore any time slice during the simulation. Rather than look at each time slice individually, though, you'll create a temporal profile of a specific location to see how its water depth changes over time.

1. On the ribbon, on the Multidimensional tab, in the Analysis group, click the Temporal Profile button.

   

   A chart view and the Chart Properties pane appear. Currently, the chart is empty. You'll define an area of interest to create the temporal profile.

2. On the scene, zoom to an area of high flooding, such as the neighborhood near Dart Street:

   

3. In the Chart Properties pane, for Define an area of interest, click the Point button.

   

4. On the scene, click anywhere in the darkest blue area near Goliad Street.

   

   The chart updates, showing the change in water depth over time at the location you clicked. Each node in the line represents a time slice in the simulation. The depth is listed in meters.

   

   In the example image, flooding reaches 0.4 meters (1.31 feet) by the second time slice. Each time slice represents five minutes, so flooding has already become dangerous only 15 minutes after the severe rainfall event began. (You didn't include the first time slice when you exported the CRF file, so the first node in the graph represents 5 minutes after the start of the event.)

   Tip:

   Point to a node on the chart to see the exact depth in meters at that time slice.

   By 30 minutes into the event, the water depth has reached 0.93 meters (3.05 feet), meaning it is deep enough to carry away SUVs and trucks, according to the Turn Around Don't Drown benchmarks. Quick warnings and response times in this area might be essential to preventing harm.

5. Optionally, explore other locations and their temporal profiles.

   Note:

   Clicking another area on the scene will add another line to the temporal profile chart. The individual lines can be turned on and off in the Chart Properties pane.

6. When finished, close the chart and the Chart Properties pane. Close the Symbology pane.
7. Navigate back to the full extent of the study area.

   Tip:

   To navigate to the full extent quickly, right-click Model Boundary in the Contents pane and choose Zoom To Layer.

8. Save the project.

By exporting the results of your flood simulation to a multidimensional CRF file, you were able to better visualize it to understand where flooding is most severe. You also created a temporal profile to understand how flooding changes over time. Next, you'll analyze the results to understand how the simulated flood will impact infrastructure.

Assess impacts to infrastructure

How will the flooding in the simulation affect structures? To answer this question, you'll run a geoprocessing tool to calculate the maximum flood depth in and around each structure feature for each time step. By joining the output table to the structures layer, you can symbolize the structures by maximum flood depth, identifying buildings likely to be impacted the most by flooding. You'll also create charts to summarize the results.

Determine flood depth for each structure

To determine the flood depth experienced by each structure, you'll use the Sample tool, which creates a table that shows the values of cells from a raster at defined locations (in this case, the locations of structures).

1. On the ribbon, click the Analysis tab. In the Geoprocessing group, click Tools.

   

   The Geoprocessing pane appears.

2. In the Geoprocessing pane, search for Sample. In the list of results, click the Sample (Image Analyst Tools) tool.

   

3. For Input rasters, choose Houston Flooding_WaterDepth.crf.

   A message indicates that only filtered records will be used. The filter means that only the current time step will be analyzed. You want to analyze all time steps, so you'll choose to use all records.

4. Turn off Use the filtered records.

   

5. For Input location raster or features, choose Structures.
6. For Output table or feature class, type Structures_Sample_Depth.

   You have the option to change the resampling technique, which sets the algorithm used to determine how values are obtained from the raster. The default option, Nearest, will use the nearest neighbor algorithm to find raster values that are closest to each structure. This option is acceptable, so you'll leave it unchanged.

   You'll change the ID field of the output table to use the building ID for each structure. By ensuring the output table has a field that matches a field in the Structures layer, you'll later be able to join the table to the structures.

7. For Unique ID field, choose Building ID.

   

   Your raster is multidimensional, so you'll process it for each time step.

8. Check Process as multidimensional.

   More options appear related to multidimensional datasets. By default, the average value will be found, but when it comes to flooding, the maximum value is most important. The highest level of flooding will cause damage, even if the water is only that high for a short period.

9. For Statistics type, choose Maximum.

   You'll also add a short buffer distance around each input feature (the structures) for statistics to be calculated. The flood simulation only extends to the edge of any 3D objects in the scene because you used them as barriers. By using a buffer, you'll ensure you capture the water depth just outside the structure's walls. Because the simulation resolution is 1.465 meters, you'll use a buffer distance of 2 meters to capture at least one cell all the way around each structure.

10. For Buffer distance field or value, type 2.

    This value uses the same unit of measurement as the input features, which is meters.

    Lastly, you'll set the output table to have a column-wise layout, meaning that each time step will have its own column. This way, you can symbolize the results by time step.

11. Check Column-wise layout.

    

    To potentially reduce processing time, you'll set the parallel processing factor to take advantage of multiple CPU cores, which many modern computers have.

12. Click the Environments tab.

    

13. For Parallel Processing Factor, type 90%.

    

14. At the bottom of the pane, click Run.

    The tool runs. It may take a few minutes to complete. When it does, the Structures_Sample_Depth table is added to the Contents pane.

15. In the Contents pane, scroll down to the Standalone Tables section. Right-click Structures_Sample_Depth and choose Open.

    The table appears.

    

    The table contains the maximum flood depth value (in meters) for each structure at each time step. The time steps are ordered from earliest to latest. The table also contains the BUILD_ID field, which matches the building IDs in the Structures layer.

16. Close the table.

Symbolize impacted structures

Next, you'll visualize the results of the sampled table on the scene. First, you'll join the table to the Structures layer. Then, you'll apply symbology that highlights structures by the maximum flood depth they experience. The result will be a scene that shows which structures will be most impacted by the simulated flood.

1. In the Contents pane, turn on the Structures layer.
2. In the Geoprocessing pane, click the Open Another Tool button and choose Open Another Tool.

   

3. Search for Join Field and open the Join Field tool.
4. For Input Table, choose Structures. For Input Field, choose Building ID.
5. For Join Table, choose Structures_Sample_Depth. For Join Field, choose BUILD_ID.

   

   Next, you'll choose the fields to join. You want to join all of the time step fields, which are the majority of the fields. You'll use field mapping to remove the few fields you don't want to join.

6. For Transfer Method, choose Use field mapping.

   A field map appears, listing all of the fields in the Structures_Sample_Depth field.

7. Point to the BUILD_ID field and click the Remove button.

   

8. Remove the X and Y fields.

   Now, only the 12 time step fields are listed in the field map.

   

9. Click Run.

   The tool runs and the Structures_Sample_Depth table is joined to the Structures layer.

10. Close the Geoprocessing pane.

    Now that the tables are joined, you'll symbolize the Structures layer based on the flood depth experienced by each building. Like when you symbolized the flood depth raster, you'll use a layer file you downloaded with the project to apply preconfigured symbology, though the process is a little different for a feature layer compared to a raster layer.

11. In the Contents pane, right-click Structures and choose Symbology.
12. In the Symbology pane, click the options button and choose Import symbology.

    

    The Geoprocessing pane appears, showing the Apply Symbology From Layer tool. The input layer is already populated.

13. For Symbology Layer, click the Browse button.

    

14. In the Symbology Layer window, expand Folders, Houston_Flood_Simulation_2 (or 1), and commondata. Click the userdata folder.
15. In the userdata folder, click Structures by Depth.lyrx. Click OK.

    The layer file is added to the tool parameters. Lastly, you'll set the field to use for the symbology. You'll symbolize the layer using the latest time step, when flooding is likely at its peak.

16. For Symbology Fields, for Type, choose Value field. For Target Field, choose the last WaterDepth_StdTime field (the one located at the very bottom of the list of fields).

    

17. Click Run.

    The symbology is applied. Now, structures are symbolized by water depth, with darker structures experiencing more flooding.

    

18. Close the Geoprocessing and Symbology panes. In the Contents pane, expand the Structures layer.

    

    The legend indicates that the symbology breakpoints are the same ones you used to symbolize the flood depth raster, ranging from under 3 inches to over 3 feet.

19. Optionally, pan, zoom, and tilt the scene to explore it and identify the buildings most impacted by flooding.

    Tip:

    For an optional challenge, or to test what you've learned, try following the same process to analyze and symbolize the flood impacts to roads:

    • Run the Sample tool with the same parameters, except using the Roads layer as the input feature layer and the Object ID field as the unique ID field.
    • Join the output table to the Roads layer using the Object ID field and the LOCATIONID field.
    • Symbolize the layer using the Roads by Depth.lyrx file.

    The road features have already been processed using the Densify and Split Line at Vertices tools to create vertices every 10 meters of every road and split the roads into individual segments 10 meters in length. Because of this, the symbolized roads will show the maximum flood depth for every 10-meter road segment, more accurately indicating where deep flood water begins and ends. The road features also already have flood depth data from a sample flood simulation, in case you want to skip the steps of running the Sample tool and joining the tables.

Configure a range slider

While you can explore the scene manually to see the flood depth for each building, your scene would be more useful if it were possible to show only buildings impacted by specific flood depths. One way to do that is by configuring a range slider. A range slider will allow you to quickly filter the buildings on the map by flood depth, so you can focus on only the most impacted buildings.

1. In the Contents pane, right-click Structures and choose Properties.

   The Layer Properties window appears.

2. Click the Range tab.

   

3. Click Add Range.

   

   To configure the range slider, you'll choose the field to filter by. In this case, you'll filter by the last flood depth field, when flooding is at its peak. You also used this field to symbolize the buildings.

4. For Start Field, choose the last WaterDepth_StdTime field (the one located at the very bottom of the list of fields).

   

5. Click Add. At the bottom of the Layer Properties window, click OK.

   On the side of the scene, the range slider appears. It's currently disabled.

6. Point to the slider and click the Range disabled button.

   

   Two handles appear on the range slider, which you can set to display a range of flood depths. By default, the range is from 0.00 to -1.00, so no buildings are displayed on the scene (because no buildings have a negative flood depth value).

   

7. Click the 0.00 handle, type the maximum flood depth value displayed at the top of the range slider (which should be 5.63 or a similar number), and press Enter.

   By changing the upper handle to the maximum flood depth value, all buildings are once again displayed on the scene.

8. Click the -1.00 handle, type 0.30, and press Enter.

   The scene is filtered to show only buildings that experienced at least 0.30 meters (30 centimeters, or about 1 foot) of flooding during the storm.

   

   By using the range slider, you can quickly filter the scene to show only buildings that your simulation indicates will experience significant flooding.

9. Optionally, change the lower handle to different values and explore the scene.
10. When finished, change the lower handle to 0.00 and return to the full extent of the scene.

    Tip:

    If you followed the optional steps to analyze and symbolize roads by flood depth, you can also configure a range slider for roads. To do so, open the Layer Properties pane for the Roads layer and configure the range slider the same way you did for the Structures layer.

Configure a flood depth chart

You now have a visual understanding of how buildings in the area are affected by the simulated flood. Lastly, you'll summarize the impacts of the flood simulation using a chart. Unlike a visual assessment of a scene, a chart will indicate exactly how many structures are impacted by different flood depths, as well as what types of structures are impacted.

1. In the Contents pane, right-click Structures, point to Create Chart, and choose Bar Chart.

   

   A chart view and the Chart Properties pane appear. You'll configure a chart that shows the number of buildings affected by flooding for each building occupancy type.

2. In the Chart Properties pane, for Category or Date, choose Building Occupancy Classification. For Aggregation, confirm Count is chosen.

   

   Tip:

   For a more granular breakdown, you can also choose Primary Occupancy for the Category or Date parameter.

   You'll also label each bar in the chart with the total count and sort them from highest count to lowest.

3. Check Label bars. For Sort, choose Y-axis Descending.

   

   The chart updates.

   

   Currently, the chart shows all buildings by type, regardless of the severity of the flood impacts. However, the chart can be used in conjunction with the range slider to show only buildings impacted by a specified flood depth.

4. On the scene, change the lower handle of the range slider from 0.00 to 0.30.

   The chart updates. Now, it shows only structures experiencing at least 0.30 meters of flooding.

   

   The filtered chart indicates that 552 residential structures will experience significant flooding, as well as 102 commercial structures and a smaller number of other types of structures.

   The chart is linked to the scene in other ways. For instance, by clicking a bar in the chart, you can highlight all buildings on the scene of that building type.

5. In the chart, click the Commercial bar.

   On the scene, commercial buildings experiencing at least 0.30 meters of flooding are selected.

   

6. In the chart, press Ctrl and click the Commercial bar to deselect the features.
7. Optionally, use the chart and range slider to explore the scene.

   Tip:

   If you followed the optional steps to analyze and symbolize roads by flood depth, you can also create a flood depth chart for roads. To do so, follow the same process you used to create the structures chart using the Roads layer. When configuring the chart, for Category or Date, choose the MAF/TIGER Feature Class Name field, which was added to the layer to provide human-readable road class names.

   It makes more sense to aggregate the roads chart by road length rather than number of features. To do so, for Aggregation, choose Sum. The road lengths are in meters by default, while kilometers would be more appropriate. For Numeric field(s), click the Set an expression button and use the expression ($feature.length_m/1000). The result is a chart that shows the length of road in kilometers impacted by flooding.

8. When finished, close the chart and the Chart Properties pane.
9. Save the project.

In this tutorial, you simulated a flood in ArcGIS Pro. Then, you explored the results by exporting them to a flood depth raster and creating a temporal profile. Lastly, you used the simulation results to assess the impacts to structures.

Understanding potential flood impacts is essential for preparing for them. Though this workflow was focused on Houston, Texas, it can be performed for any location as long as you have the necessary input data. To learn more about the input data and how many of the layers in this tutorial can be configured for your own area of interest, see Set up a flood simulation.

You can find more tutorials in the tutorial gallery.

Acknowledgements

• The Structures layer was derived from the USA Structures layer.
• The Roads layer was derived from the Transportation (Roads and Railroads) layer.
• The NLCD 2024 Fractional Impervious Surface layer was derived from the USA Annual NLCD - Fractional Impervious Surface layer.
• The USA SSURGO Soil Hydrologic Group layer was derived from the USA SSURGO - Soil Hydrologic Group layer.
• The NLCD 2024 Land Cover layer was derived from the USA Annual NLCD - Land Cover layer.
• The Model Boundary layer was created by the tutorial author.
• Environment Map sources: Esri, TomTom, Garmin, FAO, NOAA, USGS, © OpenStreetMap contributors, © World Wildlife Fund, Inc., and the GIS User Community