Canada's Massive Mackenzie River Basin (image) Walter and Duncan Gordon Foundation Share Print E-Mail Caption The Mackenzie is Canada's longest river -- about 1,800 km -- and pours a staggering 10.3 million liters (enough to fill four Olympic swimming pools) into the Arctic Ocean every second, along with 100 million tons of sediment per year. That's slightly more than the St. Lawrence River discharges into the Atlantic, experts estimate. Credit Walter & Duncan Gordon Foundation Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.