Wiktionary
peak flow
n. 1 The largest measure of air respired from the lungs 2 The largest volume of water discharged from a stream or river
Usage examples of "peak flow".
If the analogy to the channeled scablands is correct, floods involving water discharges of millions of cubic meters per second and peak flow velocities of tens of meters per second, but lasting perhaps no more than a few days, have occurred on Mars.
But at the peak flow, what he was doing jumped out at him in stark relief.