water

pipe

dirty

waste

environment

sewage

river

pollution

industry

industrial

flowing

flow

drain

tube

stream

ecology

sewer

pipeline

liquid

treatment

drainage

canal

environmental

substance

nature

tunnel

sewerage

old

toxic

garbage

floodwater

contaminate

fluid

sluice

unclean

catchment

contamination

pipes

danger

polluter

culvert

pollute

polluting

runoff

waterway

wastewater

drainpipe

flood

polluted

round

disaster