Sewer outflow under water level area

Jan Dekker

Hi,

We are working on a project where the complete (rain) sewer enters a small lake within the neighborhood. Therefore, we created a sewer system with an outflow to this lake. The only problem, the height at which the sewer outflow is situated is below the water level in the project area. Because of this, there is no outflow and all the rain stays on the streets. Is there a workaround or some way to resolve this problem?

Thanks in advance,

Jan

Godelief

Hi @Jan Dekker ,

You can change the height of the sewer overflow by changing the SEWER OVERFLOW attribute: https://support.tygron.com/wiki/Sewer_overflow_attribute_(Water_Overlay) https://support.tygron.com/wiki/Sewer_model_(Water_Overlay)#Sewer_Overflow

If you go to the Configuration Wizard of your Water Overlay and then navigate to the step about sewer overflows, you can select the outflow from the dropdown menu and change the height. You will probably also see a warning about the sewer overflow being submerged and therefore inactive. If you have adjusted the height, the wizard will validate this and either show a warning or not. This way you can see whether the sewer overflow is now functional or still inactive.

Jan Dekker

Hi,

Thanks for the quick reply. The underlying problem from this situation is that the overflow from the sewer, looking at the reality, is at -6.8m NAP. The water level from the area is at -5.8m NAP. When we run the model with these numbers there are no errors. We also see that it calculates with an average land height of -7.3 NAP. This is lower than every land height in the project area, so we don't really understand this height.

However, with these numbers, there is no water coming out of the sewage outflow. We can of course put the overflow at a higher level, but at which height will be a guess. Is it possible that Tygron calculates the pressure from the water entering the sewer system at -4 NAP and uses that so the outflow works, even though it is fully supmerged?

Thanks in advance,

Jan

Godelief

Hi @Jan Dekker ,

No that is not yet possible, but can you let us know the name of your project and give Tygron Support access to it by changing the rights? Then we can take a look into your project and see how to get the sewer overflow working.

When you go to File in your project you can set the project rights (https://support.tygron.com/wiki/Permissions, see this page with more info and images).

Jan Dekker

Hi,

Thanks for the reply. The project name is Regenboogbuurt V14 and I changed the rights as mentioned above. We already tried to get the sewer overflow working, such as choosing a higher SEWER_OVERFLOW. When this was set, the overflow was working until the water level reached this height. Therefore, choosing a height to low means to few water goes through the overflow to the lake and choosing to high means to much water.

Thanks in advance,

Jan

Godelief

Hi Jan,

Good to hear that you already managed to get the sewer overflow working. I do not have any additional tips on how to choose the most realistic sewer overflow height for your use case in where you have a sewer overflow which is submerged. How the sewer overflow currently works in Tygron is as free flowing water, without pressure etc. To make the sewer overflow functional set the overflow at the maximum height that the open water can reach due to the pressure from the sewer. This value is something you have to determine yourself.