Every year on St. Patrick’s Day, the Chicago River is dyed green to celebrate Irish heritage. This unique tradition dates back over 50 years and has become an iconic part of the city’s holiday celebrations. But how long does the river actually stay green after it’s dyed? Let’s take a look at the dyeing process and how long the emerald green color sticks around.
The Dyeing Process
The dyeing process begins a few days before St. Patrick’s Day. Members of the local plumbers union use boats and bins to pour orange dye into the river. This orange dye mixes with the river’s blue water to create a bright green color. Approximately 40 pounds of dye are used to color the river each year.
The dyeing event takes place at 9 am on the Saturday before St. Patrick’s Day. Thousands of people gather along the river banks to watch members of the Chicago Plumbers Union Local 130 pour the dye in. As the orange liquid mixes and spreads through the water, the river transforms into a vivid green spectacle.
The secret dye formula was developed specifically for Chicago’s river dyeing tradition. It contains ingredients like flour and vegetable oil. The dye is designed to be harmless to wildlife and the environment.
How Long Does the Green Color Last?
So how long does the Chicago River stay green after it’s dyed? The vibrant emerald color lasts around 5-6 hours. After this time, the dye begins to fade and dissipate.
Here is a breakdown of the timeline:
- 0-2 hours after dyeing: Peak green color. The river is a bright, Kelly green hue.
- 2-4 hours after dyeing: Color remains strong but starts fading slightly.
- 4-6 hours after dyeing: Noticeable fading to a more blue/green aqua color.
- 8-12 hours after dyeing: Most of the dye has washed away, river returns to normal blue. Only a hint of green remains.
- 24 hours after dyeing: The river is back to its typical blue, the temporary green color has completely vanished until next year.
So within about half a day, the vivid green river transforms back to blue. The color lasts just long enough for the St. Patrick’s Day celebrations and parades held along the river banks in downtown Chicago.
Why Does the Color Eventually Disappear?
There are a few reasons why the green river dye gradually fades and washes away:
- Dilution – The constant flow of the river water dilutes and spreads out the dye over time.
- Absorption – Particles in the water absorb the dye pigment little by little.
- Exposure to sun – Sunlight accelerates the breakdown of the dye molecules.
- Boat traffic – Boat propellers and turbulence help mix and dissipate the dye.
Within several hours, these factors cause the vibrant green color to be slowly stripped away. While the environmental impact is low, the man-made dye does not cling permanently to the river’s natural state.
History of the Green Dye Tradition
The annual Chicago River dyeing first started in 1962, thanks to the Chicago Journeymen Plumbers. The local plumbers union debuted the St. Patrick’s Day river tradition using 100 pounds of dye. It was intended as a test but quickly became an iconic city ritual.
Since the initial 1962 dyeing, a few others have been involved in carrying on the tradition:
- 1966: The Chicago Journeymen Plumbers stopped dyeing the river after doing it for 5 years.
- 1967-1968: No one dyed the river green.
- 1969: Tom Rowan and the Chicago Dye Club brought back the tradition.
- 1970-present: Members of the Chicago Plumbers Union Local 130 have dyed the river green every year since.
For over 50 years now, the plumbers union has dutifully kept the beloved annual tradition alive in Chicago.
By the Numbers: Chicago River Dyeing
Here are some interesting facts and figures about the green dyeing of the Chicago River:
| Year dyeing began | 1962 |
|---|---|
| Pounds of dye used | Approx. 40 lbs |
| Dye color before mixing | Orange |
| Dyeing event start time | 9 am |
| Dye poured from | Boats and dye bins |
| Who pours the dye | Chicago Plumbers Union Local 130 |
| Peak green duration | 2 hours |
| Time for dye to fade | 6-12 hours |
Environmental Impact
Despite being a man-made process, the green dyeing of the Chicago River has a relatively low environmental impact. The dye is specifically designed to be biodegradable and safe for plant and animal life.
In 1966, the Illinois Attorney General tested the ecological effects of the dye. They found it did not negatively harm water quality, plants, or fish populations. The vegetable-based dye even serves as a food source for some microorganisms in the river.
While the dyeing tradition has continued, environmental laws have also gotten stricter over the decades. The Plumbers Union works closely with the Metropolitan Water Reclamation District to ensure proper water quality and safety is maintained.
Significance of the Green River Ritual
So why go through all this effort each year to dye the Chicago River green? The act has important cultural significance for the city.
First, it transforms the Chicago River into a symbolic Irish waterway. Turning the river green helps kick off the city’s enormous St. Patrick’s Day celebrations and parades. The eye-catching display also draws crowds of spectators and tourists.
Second, it reflects the pride Chicagoans take in local traditions. Unique events like the river dyeing create civic identity and bring people together. The plumbers have kept the beloved ritual going for over 50 years now.
Finally, the river’s green transformation signals the impending arrival of spring. Despite its brevity, it’s a lively display of color that contrasts winter’s grey landscape with a bright, verdant hue.
Future of the Green River Custom
What does the future hold for Chicago’s iconic green river tradition? There’s no reason to think the annual dyeing will stop any time soon.
The Chicago Plumbers Union remain committed to carrying on the St. Patrick’s Day ritual started by their forebears. Generations of Chicagoans look forward to the familiar spectacle each March. As long as the plumbers continue their work, the Windy City will have its green river.
Of course, environmental regulations could impact how the dyeing is done. But the Plumbers Union works closely with authorities to follow proper protocol. As long as they do, the emerald green river should flow for years to come.
Conclusion
The green dyeing of the Chicago River has become an iconic local tradition. Each St. Patrick’s Day, a bright green hue washes over the river for several hours. But the emerald color is only temporary. Within 6-12 hours, the river transforms back to its normal blue.
While brief, the annual dyeing ritual has important cultural meaning in Chicago. It kicks off holiday celebrations, creates civic pride, and signals the coming of spring. As long as the capable Chicago Plumbers Union continues the tradition, locals and tourists alike can continue enjoying this unique display.