Hello, I created a model and included tidal conditions. But from my point of view, the result is not plausible.
The calculation starts with the maximum water level (elevation: 4,98 m) based on a Time-Elevation-Curve
Boundary Conditon Typ: Tidal
Tidal Gate: False
The correct water-level is shown during the calculation time-steps (?).
By using the Hydraulic Reviewer to check the Overflow Volume it gives me a total amount of about 10 m3. That is not plausible. Can someone assume where my mistake is?
And here are the files
0407.Strang_1 ohne lateral 20180817.stsw.zip7128.Strang_1 ohne lateral 20180817.zip2018-08-19_Pegelrohdaten St_Pauli.zip
The profile you provided is for scenario "Dynamisch Überflutung r-15-30".When I open the model you provided this scenario doesn't have outfall O-1 set to use a tidal boundary condition type. Perhaps you didn't save the model before uploading it or you uploaded an older revision of the model?
From the image of the Cyclic Time-Elevation Curve you provided for outfall O-1, it appears that you are using the values from your spreadsheet's "Wasserstand Zustand 5 Faktor 2,5" column.
The image of the curve data you provided starts with time=1min, however the elevations start with values that correspond with time=0min (in the spreadsheet).
I recommend starting with time=0min and use the elevation values that correspond to these times in the spreadsheet.
Note that there is a difference between entering this data starting at 0min and 1 min. The following profile shows how this change will impact the results.
I am not seeing a total overflow volume of about 10 cu-m reported in the Hydraulic Reviewer for catchments or manholes in either of these configurations/scenarios.
Try correcting the values in the "Cyclic Time-Elevation Curve" to match the values in the spreadsheet.If that doesn't help, then please provide the updated model files and images of matching results that you believe are incorrect.Why do you believe the results you are seeing are not plausible? The results that I'm seeing appear to be reasonable for what is being modeled. Were you expecting the total overflow volume to be less or more than 10cu-m?
What software are you using?
Is this an existing system that you want to find out how much will overflow, or are you designing a system to avoid overflow?
Here are some related articles that might be helpful.
How to find volume (such as overflow volume) through specific elements
Troubleshooting unstable SewerGEMS and CivilStorm results using the implicit solver
Bentley Technical Support
Answer Verified By: Michael Schäffer
One quick note to add along with Craig's answer:
The screenshot of the profile shows the result at time zero. The red lines indicate the maximum HGL at each node, and you can see that it is above the ground elevation for most of the network, which is likely the cause of the overflow volume, in the particular case that you were looking at (which may be different from the model that you sent, per Craig's reply). Be sure to move forward in time using the Time Browser, to see what happens later in the simulation.
If the overflow is unexpected, check your Continuity Error and general network stability, and adjust the advanced calculation options per the second article that Craig linked to.
Jesse DringoliTechnical Support Manager, OpenFlows ProductsBentley Communities Site AdministratorBentley Systems, Inc.
I have used CivilStorm since one year on and off, so I am not very experienced in the application of the software and to use the forum. I am sorry for that. I use MS with CivilStorm (Connect Edition) because of the existing project structure.
The system does exist and I would like to calculat the overflow volume depending on the tidal/water level. In a second step I would like to integrate the existing pump stations to drain the area (outfall will be closed).
I thought the results were not correct because when I increased the water leve I got nearly the same outputs. But your were right. The time -curve was incorrect. Maybe I made I mistake by copy and paste the values into the software. I did the correction and now my curve looks right.
On your and my curves I see a negativ outflow. Is the reason the empty storm water network by t = 0? Do I have to define the water-level in the stormwater network for the calculation start?
I will check the links you have recommended and I thank you for the great help.
Michael Schäffer said:On your and my curves I see a negativ outflow. Is the reason the empty storm water network by t = 0? Do I have to define the water-level in the stormwater network for the calculation start?
What do you mean by negative outflow? Is the "Flow (Total Out)" field in the Outfall properties reporting negative outflow?
It would be helpful if you shared a snapshot of what you are seeing.
The flow in the storm-water conveyance system is generated from the runoff from your catchments.
The negative flows may be related to the hydraulic grade in the system. Since you are defining the elevation at the outfall, if the elevation is higher than the hydraulic grade further upstream, this may result in flow moving upstream into the network.