How to Use the Hydrology Tools

The hydrology tools can help you effectively prepare for hydrological (water/rainfall) events. They simulate how water might flow given the current surface of your worksite. 

How to use Flood to Level Analysis

Flood to Level Analysis helps visualize the potential impact of a flood at specified water levels. This tool is essential for emergency preparedness and risk management, providing immediate visual feedback on flood and rising water scenarios.

Click on the HYDRO tab and select Flood to Level.

Hydro Flood to Level.png


Hydro Pick Flood Level From Map.png

Select a point on the map to simulate how water would flow.

Pick Flood Level From Map Example.gif

You can also change the reference level if you want to start the flood level from a specific elevation on the map.

Hydro Flood to Level Change Reference Level.png

How to use Surface Runoff Simulation 

Understanding water flow is crucial for planning drainage and containment strategies.

The Surface Runoff tool simulates and shows water flow across a site during rainfall or spills. This feature includes options to indicate flow direction and spill impact areas using the point and polygon tools.

We currently use constant values for friction (Manning's value) and infiltration across the simulation region.

From the HYDRO tab, select Surface Runoff.

Hydro Surface Runoff.png

Preferential Flow Path

The Preferential Flow Path option shows the downward direction of flow. Check the checkbox to turn on this option and see where water may flow or collect across your site. This can help identify areas where standing water may occur or drainage is incorrect.

 Surface Runoff Preferential Flow Path.png

Surface Runoff Preferential Flow Path Example.png

Liquid Drop Analysis

The Liquid Drop Analysis option focuses on a specific area of the site. It generates a visual representation of where liquid may flow and collect in the event of a spill.

You can draw a circle or custom polygon around the point on the map where you want to see the Liquid Drop Analysis.

 Surface Runoff Liquid Drop Analysis.png


Click a point on the map and use the slider to change the radius size around your point.

Turn on this option by checking the checkbox and setting the radius (in meters) of the area you want to see. 

Surface Runoff Liquid Drop Analysis Circle.gif


Similarly, choose the POLYGON option and draw a custom boundary around the area you want to see. The liquid drop color gradient helps indicate the flow's direction from red to purple.

Surface Runoff Liquid Drop Analysis Polygon.gif

How to use Catchment/Watershed Analysis

This tool allows you to draw regions and automatically generate breached stream networks to analyze the effectiveness of watersheds and identify catchment areas.

This tool helps you understand the size and shape of the catchment area that feeds into a stream or dam on your worksite.  Understanding catchments can help you plan to mitigate extreme weather events.

To use this tool, you must first compute a breached stream network for the area you are interested in. Once done, you can click on one of the streams to compute the catchment area and display the watershed.

A breached stream network has had a breaching algorithm applied to depressions in the DEM before computing the stream network.  This allows depressions to overflow to lower worksite areas during catchment area calculations, as in extreme weather events.  This means the stream network you see may not always flow in a downhill direction.

From the HYDRO tab, click Catchment/Watershed Analysis.

Catchment Watershed Analysis.png

Follow the workflow by selecting a previously saved polygon, or create a new one from the dropdown list to use as your simulation region. 

Note that inflows and outflows outside the simulation region won't be modeled.

Catchment Watershed Analysis Pick Simulation Region.png

Catchment Watershed Analysis Create New Region.png

Click PREPARE SIMULATION REGION. Once ready, click on Show Stream Network to turn on the simulation.

Catchment Watershed Analysis Show Stream Network.png

Once generated, the arrows show the directional path of the stream network.

Catchment Watershed Analysis Show Stream Network Example.png

You can pick an area on the map (the OUTFLOW POINT) to see a shaded representation of all the stream networks contributing to that overflow.

Catchment Watershed Analysis Outflow Point.png

How to run a Direct Rainfall Simulation 

Based on a rainfall graph, this tool simulates surface water runoff and pooling on your site.  This is useful in preparing for and understanding how water will pool and flow on your site for various rainfall events, including approximating 10-year or 50-year rain events/floods.

Select or create a new Simulation Region.

This simulation can take several minutes to several hours to generate, depending on the size and complexity of the area selected.

Direct Rainfall Select Simulation Region.png

Click SIMULATE DIRECT RAINFALL. Then, select the parameters for the simulation.

Simulation name: The name that will be displayed in the list of simulations.

Simulation length: The number of hours that will be simulated.

Rainfall: The rainfall rate during the simulation. Customize the rainfall graph by selecting a rainfall CSV.

You can either download the example RAINFALL CSV and customize it or upload your own Rainfall CSV.

  • To edit the example, click the DOWNLOAD RAINFALL CSV button and edit it to customize. 
  • Or click UPLOAD RAINFALL CSV and select a suitable file.  

Note that if the CSV is shorter than the simulation length, the last rainfall rate will continue to be applied for the remainder of the simulation.

Simulation speed/accuracy: This affects the grid cell size used for the simulation. 

Depending on your needs, you can select:

Faster (2m grid, or ~6.5ft grid), 

Average (1m grid, or ~3.5ft grid), or 

More accurate (0.5m grid, or ~1.5ft grid).

Water depth gradient: The gradient style/colors that will be displayed on the map to show water depth. 

Note this is not editable after the simulation is complete.

Water depth gradient maximum: The upper end of the gradient scale. Depths greater than this will appear as the darkest color in the water depth gradient. 

Note this is not editable after the simulation is complete.

Catchment Watershed Analysis Direct Rainfall Select Parameters.png

Once the simulation is complete, select it in the left-hand panel and move the time slider to view the water depth at different times during the simulation.

Direct Rainfall View Completed Simulation.png.png


Learn how to simulate, plan, and manage water and rain events with Propeller's new hydrology tools on our YouTube channel.

I still can't do it!

We wrote these articles to equip you with everything you need to get the job done on your own, but we understand that sometimes this isn't sufficient.

If you're stuck, you can connect with our support team by clicking the support button on the top right corner of your user portal.

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