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