As one of Canada's major commercial ports, the Port of Toronto helps to ensure the safe navigation of more than 7,000 recreational boaters; 100 lakers; dozens of Harbour tour vessels; visiting cruise ships; and 35-45 international or ocean-going ships per year. PortsToronto owns and operates Marine Terminal 51 and Warehouse 52 within the Port of Toronto. The 50-acre PortsToronto marine terminals facility has more than 225,000 square feet of warehouse space and over 30 acres of paved marshalling area, for short/long-term storage, warehousing and project staging. PortsToronto'a International Marine Passenger Terminal saw 15 cruise ships visit over the 2015 summer season, bringing 5,400 passengers through Toronto. In 2013, the Port of Toronto moved close to 1.6 million metric tonnes of cargo by ship, including salt, sugar, cement, and high-value project materials needed to support Toronto’s booming construction industry. Cargo travels to/from countries such as Germany, Australia, South Korea, China and the U.S.A. Delivering 1.6 million metric tonnes of bulk cargo by ship via the Port takes about 40,000 40-tonne trucks off congested roads and highways. PortsToronto's Harbour Clean-Up Program sees the removal of approximately 1.8 million pounds (500-800 metric tonnes) of floating debris and driftwood from the Harbour each year – the equivalent weight of one car every day of the year. PortsToronto dredges between 20,000 and 40,000 cubic metres of material from the bottom of the Keating Channel each year to prevent flooding of the Don River and keep sediment from the inner harbour. This is equivalent to the size of 85 refrigerators being collected on every day of the year.