The Great Lakes are also the primary source of industrial water use for the region. The International Joint Commission has identified over 300 toxic chemicals of concern in the waters and sediments of the Great Lakes. Drops in water levels mean those chemicals are less diluted. Lower lake levels also increase the risk of disturbing contaminated sediments making them more mobile for uptake through the food chain. The commercial viability of already shallow harbours and connecting channels can also be impacted.
Climate change adds more uncertainty and demands a prudent and comprehensive approach.
This is more than six times the average daily outflow from Lake Ontario to the St. Lawrence River. Ninety four per cent of those withdrawals were for hydroelectric power. Consumptive use of the waters of the Great Lakes results in permanent water loss from the system. In 1992, consumptive use in the Great Lakes Basin amounted to 11 million litres of water per day. Global water use per capita has increased by over five times in the last 300 years.