The canals and navigable rivers of Burgundy extend over 621 miles (1,000 km) divided into three canals and a river, the Seille, a tributary of the Saône reserved for pleasure boating over 30 miles (49 km). The longest of the canals is the 'Canal de Bourgogne' (150 miles / 242 km), followed by the Canal du Nivernais (110 miles / 178 km) and the Canal du Centre (69 miles / 112 km). Navigating these watercourses requires the use of maps of the navigable network to visualize the routes, know their mileage, the number and size of the locks, the drafts, the ports and the possible stops ... More touristic brochures are also distributed by the boat rental companies to their customers.