Water quality monitoring in the connecting channels of the Great Lakes is part of Environment and Climate Change Canada’s commitment to the Canada-United States Great Lakes Water Quality Agreement (GLWQA) under the auspices of the International Joint Commission (IJC, 1989) to evaluate the effectiveness of pollution control programs carried out in the Great Lakes Basin. Water quality monitoring in the Connecting Channels began with the establishment of a fixed sampling site on the Niagara River at Niagara-on-the-Lake (NOTL) in 1975 and, over the next decade, additional sites were added on the St. Lawrence River at Wolfe Island in 1976 and upstream on the Niagara River at Fort Erie (FE) in 1983. Monitoring in the St. Clair River began at two locations, Port Lambton and Point Edward, in 1987.