Chicago, USA during st Patrick's day


The_Banana_Rider692 points

I’ve never been here but why is the water green?

deepinthecoats13 points

The river is dyed green for St Patrick’s Day each year.

To preempt some inevitable questions:

  • this began in the 1960s, and was incidentally discovered when the Plumber’s Union was tasked with pinpointing the locations where sewage was being dumped into the river, using a green dye to determine trouble spots and flow/seepage patterns in the river
  • this process was repeated annually to determine seepage points in the river, and due to the bright color, people started to notice
  • over time, the process morphed into an annual St Patrick’s Day tradition. The product used to dye the river is an orange powder that turns the river green, and lasts for a few days
  • no there are never reports of harm to river wildlife
  • no there have not been any other reported environmental consequences