Turbine (or other) discharge

[Karin&Bethi]

Dear Chris,

To overcome initial condition difficulties, one can fake the initial flow by allowing a little turbine flow before failure occurs. If this turbine flow makes a significant difference in the filling of the upstream reservoir, the reservoir loss can be added to the upstream reservoir inflow hydrograph.

And now my question:
Does this “baseflow”, which is already in the river channel, when routing starts (this "baseflow" exists already in the x-sections further downstream at routing time 0hrs), affect the computed outflow hydrograph? Respectively, is then the peak of the outflow wave higher than it would be without the turbine discharge?

Sincerely,
Karin

[Chris Maeder]

Karin:

With regard to your question on how much increasing base flow affects the downstream water surface elevations, it all depends upon how much additional base flow you are adding.

If the percentage of additional base flow is much less than the peak discharge from the routing of the flood wave, I would not be concerned about it.

Sincerely,

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