affluence afflux affluxion cascade cataract chute collapse comedown concourse confluence conflux course crash crosscurrent current debacle declension declination descending descension descent discharge down downbend downcome downcurve downfall downflow downgrade downpour downrush downtrend downturn downward trend drain drainage drift driftage drop dropping effluence efflux effluxion effusion exhalation exhaust fall falling flow flowing flowoff fluency flux gravitation gush inclination inflow mill run millrace onrush onward course outfall outflow outflowing outpour outpouring plummeting pounce race rapids run runoff rush set spate stoop stream surge swoop tide trend undercurrent undertow water flow waterfall