Demo Watershed Project

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The Demo Watershed project

The Demo Watershed project is available for all users with Preview access and can be found in the main menu under Edit projects. This project does not count towards your license.

This project is intended for hydrologists and other water experts.

This project showcases the Watershed Module.

The Demo Watershed project demonstrates the Watershed Overlay in a testbed setting. It can serve as a working demo to further explore the details of the available components, the used models and formulas and the configurable parameters.

Exploring the project

Boundary conditions and input

  1. Click on the Pumping stations Overlay in the Overlay bar (see image). Notice the highlighted areas under the grey water tap. These areas are two outlets which remove water from the project. These areas are marked as discharge areas as input for the Watershed Module.
  2. Select the Water level areas Overlay and notice the two water level areas.
  3. Go to the Rainfall Overlay and play the Overlay. This Overlay shows the Surface last value result type of a heavy short rainfall. The blue with red lines are culverts, which connect the water terrains. The blue with orange lines are the outlets.
  4. Select the Surface elevation result type and notice the forest area is higher than the rest of the project area.
  5. Take a look at the Surface avg direction result result type. The arrows show the average flow direction of the water. Notice that in the forest area, the arrows point inwards. Zoom out a bit and play the Surface average direction result type and notice that around timeframe 25 the direction of the arrows stay the same. This result type is used as input for the Watershed Module for the direction of the rainwater flow on the terrain.

Results

  1. Take a look at the Watershed Overlay. This overlay shows the calculated watershed areas. For example: rainfall water that falls on the terrain in the red watershed area, flows to the water terrains in the red watershed area. Notice that the colors of the watershed areas are the same as their corresponding discharge areas. (see Pumping stations Overlay) Notice that the forest area is not part of a watershed area, since the forest retains the water. Also check out the Surface Average Direction result result type for this forest area.
  2. Select the Discharge areas result type and notice that the initial discharge areas (see Pumping stations Overlay) are propagated with much more water terrains by the culverts (water connections). Zoom in to the yellow arrow on the edge of the two discharge areas and notice that the flow in the two culverts on either side of the arrow is opposite. This is an option in the Watershed configuration wizard, to use the culvert flow direction for propagating the discharge areas.
  3. To highlight this, go to the Base types result type and see the Blue Entry and Green Exit point of this culvert. The entry and exit points represent where water flows in and out of the culvert.
  4. Click again on the Watershed Overlay and notice that the road area depicted with the question mark icon is also not part of a watershed area. Since there are no culverts that connect the water terrains parallel with the road with the other water terrains, the water terrains next to the road are not included in the watershed calculations.
  5. Click on the Watershed indicator in the top bar. This indicator shows the surface area of the watershed areas and of the land that does not belong to a watershed area. This indicator is created by using the Tygron Query Language in an Excel.

Analyse

Remaining water
To calculate watersheds in the remaining water terrains, such as the water terrains near the question mark icon, take the following steps:

  1. In the Current situation tab, click on the Overlay button. Select in the Left menu the Watershed Overlay and open the Configuration wizard in the right panel.
  2. Click Next until you reach step 2. In step 2, check the option Discharge remaining water and take note of the min area m2 option in the wizard. With this option checked, water terrains that are larger than the set minimal area size are now also taken into account as unique discharge areas.
  3. Click several times on Next in the wizard, until you can Finish the wizard.
  4. After finishing the wizard, the overlays will be recalculated. Notice the area near the question mark is now also included in the Watershed Overlay.
  5. Open the Watershed indicator and notice that the area size that is not assigned to a watershed area is much smaller. Go back to the configuration wizard and uncheck the Discharge remaining water option for the next steps.

Water connections
To analyse the effect of the water connections and the configurable parameters, follow the next steps:

  1. Go to the culvert, highlighted by the orange culvert icon and click on this icon. Set the Culvert threshold on 2m, so this culvert does not connect the water terrains anymore. Click on Send to adjust the value.
  2. When the overlays are done calculating, go to the Watershed Overlay and notice how the watershed areas have changed. Since the water cannot flow through the culvert to the other water terrains, part of the water terrains are not included in a watershed area anymore.
  3. Click on the Future design tab and stop the test run by clicking on the stop button. Go back to the Current situation tab and open the Watershed configuration wizard.
  4. In the wizard, click Next until you reach step 4. Uncheck the culvert flow direction option and click on Finish.
  5. Repeat step 1 and notice that the watershed areas stay the same. Since the culvert flow direction is not taken into account, the presence of the culvert connects the water terrains and are therefore taken into account in the Watershed Overlay.
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