An article in Vol. 83, No. 3 (1979) of The Wisconsin Engineer confirms that, indeed, one can safely say that the celebration of St. Patrick's Day is an established tradition in the UW College of Engineering. According to the article's author, Nikki Abramoff:

“The St. Patrick's Day tradition started at the UW around 1915, when the students learned the true story of St. Patrick. The famous patron saint of Ireland was not only a great religious leader, he was also a highly educated engineer and lawyer.

“[This discovery] was found to be a fitting excuse for a party during a somewhat dull month, and so the holiday began.”

The original celebration was a tame one, but it reached a raucous peak during the 1930s. By that time, it was traditional on March 17 for the engineers and lawyers to pelt each other with snowballs across the hill. Being resourceful, the engineers came up with a substitute for snowballs — rotten eggs. The first use was limited to the number of rotten eggs available in the area, but in succeeding years, the smelly ammunition was shipped in from Chicago by the carload. Anyone who walked on Bascom Hill that day (where the engineers and lawyers occupied opposing buildings), knew it was St. Pat's day by the smell. And those who marched in the annual parade were smart to wear plastic overcoats.