A tradition celebrating its 61st year, the Chicago River is dyed green the Saturday before each St. Patrick’s Day — unless the holiday falls on a Saturday. The dyeing process starts at 10 a. m. Saturday, March 11 , and stretches from Orleans Street almost three quarters of a mile east to Columbus Drive. [ Vintage Chicago Tribune: IRISH in Chicago ] How the tradition began Mayor Richard J. Daley is credited not only with reviving Chicago’s St. Patrick’s Day parade , but also proposing the idea of greening part of Lake Michigan to celebrate the holiday. It was his boyhood friend and Chicago Plumbers Union business manager Stephen M. Bailey who suggested dyeing the Chicago River instead. The Chicago River would run green for the first time in 1962 (the same year the photo below was taken), one year after Savannah, Ga. , unsuccessfully tried to dye its river green for the Irish holiday. The first year of river-dyeing, the boat crew used an oil-based Air Force dye that kept the river green for nearly a month and caused an outcry from environmentalists. So a vegetable dye was substituted. (Chicago Tribune Archives) City workers use vegetable dye to turn the Chicago River green for St. Patrick's Day in 1976. (Mario Petitti/Chicago Tribune) The first person entrusted with turning the river green was William J. Barry, a Chicago port employee who died in 1985. Mike Butler assumed the role in the early 1970s. “Bill was from Bridgeport,” Butler told the Tribune in 1995 . “The mayor trusted him. Bill’d do anything for the mayor. Even though he was a little afraid of water, he went out there. That’s how much he loved the mayor. ” Butler led the volunteer crew for more than 40 years. He died in 2016 , but the annual dyeing of the Chicago River for St. Patrick’s Day is still a family reunion for the Butler and Rowan clans, the two families responsible for the tradition of turning the murky water into a bright “Ghostbusters” Slimer green . “It’s not the easiest job in the world. It’s messy. It can be dangerous at times. You go back and forth in the water, and you could hit something and that could tip over the boat. ” — Mike Butler, crew captain, in 1995 Mike Butler, who was in charge of dying the Chicago River green for St. Patrick's Day for more than 40 years, died July 12, 2016. He was 81. (Chuck Berman / Chicago Tribune) How the Chicago River is dyed green According to Tom Rowan, head of the crew Prep work: Early in the morning, the crew arrives at a city boat slip on the North Branch of the river. Everyone wears clothes and shoes they don’t mind getting dirty and a white paper smock over their clothes. “The washer machine — if you’re not careful, the next load of clothes will come out with a green tinge to them. ” — Mike Butler in 1995 On the water: The crew hops aboard two small motorboats donated by volunteers. The larger boat, at approximately 18 feet, has a crew of four. The smaller boat, a 12-footer, has two people. “There’re times when there’s ice in the river, and that’s when you worry. You hit a chunk of ice — hell, the bow of that boat, it wasn’t made to be an ice-breaker. ” — Mike Butler, crew captain, in 1995 A 10 a. m. start: The larger boat is responsible for dyeing the river, which begins when it arrives under the Michigan Avenue bridge near Wacker Drive. “It’s a ritual of the parade. A lot of people figure it wouldn’t even be right if they didn’t see the green river. ” — Mel Loftus, St. Patrick's Day parade grand marshal in 1995 Kitchen secret: Three men use flour sifters to dump about 40 pounds of an environmentally friendly orange powder into the river. The fourth drives the boat. The formula for the powder, which turns the water bright green when it hits, is top-secret. “I don’t know how you can write about this, but your bodily functions change for a day afterward. (The orange powder) makes everything green. ” — Mike Butler, crew captain, in 1995 Powder spread: The smaller boat “chases” the larger boat and churns up the water, which helps disperse the powder across the river. Traveling the river between Wabash Avenue and Columbus Drive, the large boat snakes across the waterway dumping powder. “We feel very much like we are the chosen. They applaud us. People tip their hats to you. You feel like you’re king for a day. ” — Mike Butler, crew captain, in 1995 Green sheen: It takes about 45 minutes for the river to turn completely green. Depending on which direction the wind is blowing, the water can stay green for up to a few days. “If you drank it — except for the pollution in the river water — it wouldn’t hurt you. It’s just food coloring. ” — Mel Loftus, St. Patrick's Day parade grand marshal in 1995 That one time the river was dyed blue A crew dyed the Chicago River blue in 2016 to celebrate the World Series champion Cubs on the day of the team’s victory parade and celebration. Watch a time-lapse video of the Chicago River being dyed blue for the Cubs World Series celebration on Nov. 4, 2016. (WGN-TV) (Chicago Tribune) Sources: As told to the Chicago Tribune by Tom Rowan and Michael Butler, whose families have been involved in dyeing the Chicago River since 1962; illustrations by Rick Tuma; Chicago St. Patrick’s Day Parade Committee; Choose Chicago ; Tribune reporting and archives interactive_content.