Water gotta go home

Under Kamiyashiro Station flows a small creek.
Concrete catch-all receptacle of a large city.
Full of algae.
Tadpoles.
Your occasional soccer ball lost forever.
Discarded cans.
Bazillionand one cigarette butts.
A couple of kilometers down its concrete trench it joins the Tempaku River.
Koi. Ducks. Bass. Your occasional Aiyu. Turtles. Snakes. Frogs.
Homeless colonizing bridges.
When it rains but good, best be up off the bank.
Meter+ rise in a few minutes.
Flush.
Water gotta go home, city or no.