air
autumn
cascade
coast
cold
current
danger
downstream
eddy
environment
fall
fast
floods
flora
foliage
free
heavy
hike
mouth
muddy
outdoor
outside
peril
pollution
quiet
rainfall
rains
rapids
river
rush
rushing
see
space
splash
spray
stream
stroll
sun
sweep
swept
tranquil
trek
upstream
valley
vegetation
walk
wash
water
wet
white