Gulfstream Park illegally discharged pollutants into a canal that flows to the Intracoastal Waterway for at least four years starting in 2011, according to a lawsuit filed this week by the U.S. Attorney’s Office. The horse racing track could face fines of $37,500 a day per violation – or more than $50 million — for violating the federal Clean Water Act, said the lawsuit filed Wednesday by the …