brown

canal

channel

concrete

creek

culvert

dirt

dirty

discharge

ditch

drain

drainage

ecological

environment

environmental

exit

flow

flowing

flush

garbage

green

industrial

industry

liquid

nature

outflow

outlet

overflow

pipe

piping

pollution

public

rainwater

round

runoff

rust

sanitary

sewage

stagnant

stormwater

stream

system

toxic

tube

underground

untreated

waste

wastewater

water

waterway