How did Canada and the United States cooperate to reduce Great Lakes pollution?

Canada and the United States have collaborated for over a century to manage and protect the Great Lakes, primarily through the International Joint Commission. Established by the 1909 International Boundary Waters Treaty, this commission was tasked with preventing disputes and overseeing issues related to shared boundary waters, including the regulation of water quality and the mitigation of water pollution.1

Following the environmental crises that became prominent after World War II, international cooperation intensified to address concerns such as eutrophication and the accumulation of toxic substances. Since the 1970s, authorities from both nations have undertaken major cooperative efforts in pollution control. These initiatives have been essential in improving water quality and supporting the recovery of various fish populations. Furthermore, conservationists have advocated for strategies such as the diversion of treated sewage away from the lakes to help maintain water integrity.23