canalization
channel
collector
concrete
corridor
creepy
danger
dark
decay
deep
dirt
dirty
drain
drainage
empty
environment
exploration
exploring
flooded
flow
glow
illuminated
industrial
industry
inside
light
mud
oviform
ovoid
passage
pollution
river
sewage
sewer
sewerage
sludge
smelly
splash
stinking
stone
storm drain
stream
subterranean
tunnel
turning
underground
urban
wastewater
water