CHICAGO (CBS) — Thousands of green-clad Chicagoans celebrated St. Patrick’s Day Saturday first with the annual river dyeing, followed by the parade down Columbus Drive.

It almost sounded like a sporting event along the banks of the Chicago River as crews dyed the water green, reports WBBM’s Mike Krauser.

Thousands of people lined both sides of the river cheering as crews from the Plumber’s Union Local 130 carried on the unique Chicago tradition dating back to 1962.

Pat McCarthy, parade coordinator with the Plumber’s Union says it happened almost by accident. Some plumbers were working with dye to detect leaks.