Piping failure centreline elevation

Mr. Maeder,

I am trying to model a piping failure of a dam (Dam Crest at 829.4 m, Water Surface Elevation at Time of Breach 826.2). The dam cross section bottom width is at least as wide as the channel height, which in this case is 12.2 m (Bottom of Dam = Bottom of Breach Elevation 817.2 m). The model does not generate results at these elevations. Only when I place the piping failure centreline elvation and the bottom of Breach Elevation at 871.2 m (which is halfway between Water Surface Elevation at Time of Breach and the Bottom of Dam/Breach) am I able to generate data for all breach parameters necessary for a piping failure inundation study.

Please advise.

(More specifically, is the piping failure centreline elevation, the elevation at which piping failure/rectangular orifice is initiated? From the User's Manual in section 6.6.2 is h (subscript f) the piping failure centreline elevation?)

Thank you.

Miroslawa Hirna, E.I.T.
Water Resources Engineer
UMA Engineering Ltd.
Email: mhirna@umagroup.com

Dear Miroslawa Hirna :

The model might be experiencing some tailwater submergence effects that are preventing you from lowering the piping elevation at the bottom of the dam. Or, there might be some other effect that is causing this problem.

If you have any additional questions or need any further information, please contact me again.

Sincerely,

Chris E. Maeder, M.S.
Senior Technical Engineer
chris.maeder@bossintl.com

One more question:

More specifically, is the piping failure centreline elevation, the elevation at which piping failure/rectangular orifice is initiated? From the User's Manual in section 6.6.2 is h(subscript f) the piping failure centreline elevation?

Thank you.

Dear Miroslawa :

The elevation that you specify is where the piping failure starts at.

If you have any additional questions or need any further information, please contact me again.

Sincerely,

Chris E. Maeder, M.S.
Senior Technical Engineer
chris.maeder@bossintl.com