QUDM reports bug

[Tim Evans]

Hi,
The latest QUDM states”
As of 2016 it has been noted (e-­mail correspondence) that problems exist within the RORB that may adversely impact on its ability to model complex detention basin outlet systems where the outlet pipes are set a different elevations. As a result, the model may not accurately calculate detention storage routing because of its assumptions for downstream tailwater level. Later updates may have resolved this issue.”

Is this still the case, or has it been fixed ?
Tim

[RoryNathan]

Hi Tim,
I haven’t seen anything in the QUDM manual on this, but it is worth stating that this “problem” is not an error that needs fixing, it represents a type of situation that RORB was never developed to cater for. RORB is a hydrologic model thus not well suited to dealing with hydraulic controls that may influence flood behaviour. The influence of such things as tailwater levels on outlet works are best evaluated with hydraulic models, though if these relate to reasonably predictable d/s conditions then it would be possible to include this in the RORB model via a bespoke S-Q-E relationship. That is, use a hydraulic model to asses how tailwater levels influence outflow rates, then input that relationship into RORB for design purposes.
Cheers,
Rory

[Author]

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