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Note that there is an example model that illustrates this situation. Please look in the StormNET Lessons folder labeled "Lesson Siphon".
Also, we have added additional material to the next StormNET User Manual regarding modeling of pressurized flow and flooding flow. And, the next StormNET shows open channel links that are flooding on the plan view. This new release should be available in a couple of weeks. Contact our technical support team if you want to try out a beta of this next release. (This also includes the new User Manual.)
The "Max/Rim Elevation" entry defines the elevation of the junction manhole rim (or height of the junction above the junction invert) in ft or m. If you are modeling a pipe bend without a manhole, this should be the height of the pipe. If you are modeling a channel, then this should be the height of the ditch.
The "Surcharge Elevation" entry is used to denote the elevation value (or depth above the junction invert) when pressurized (surcharged) flow changes to flooding overflow (ft or m).
To simulate bolted (sealed) manhole covers and force main connections, then this value should be the specified high enough above the MAX/RIM ELEVATION value so that the computed hydraulic gradeline is less than specified value. When the computed hydraulic gradeline is greater than this specified value, flooding is assumed to occur at the node.
Note that if the manhole is to be allowed to overflow and flood, then the node cannot become pressurized and this value should be set equal to the junction invert or 0. Then, when the computed hydraulic gradeline is above the MAX/RIM ELEVATION, flooding will occur. Similarly, to simulate a blowout of a manhole cover, this value can be set equal to the specified MAX/RIM ELEVATION value.
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