If the Flow simulation period is 2 weeks and resulted that it was not
enough for the DO and BOD curves in observation points to be
stabilized according to Steer-Philips equation. Do I have to run the
Flow model for longer time or just I need to increase the WAQ
simulation period - with same Flow simulation period- ?
Also in general, if I increased the WAQ simulation period than the
Flow, will the model re-use the flow cycle starting from the first
time-step or it will use the last time-step calculations as constant
to be governing? knowing that the flow is steady.
WAQ will reuse the hydrodynamic result cyclically if the WAQ
simulation period exceeds the FLOW simulation period. That does mean
that you have to be a bit careful about the precise period of the
hydrodyamic calculation: the start of the (converted) flow field and
the end should be close enough, that is end at the same tidal phase,
preferrably highwater. Otherwise there would be a large jump in the
water volume from the last time in the flow result to the first time,
resulting in a mass error. This is corrected for, but still the
smaller the correction, the better.