Along its course, the Garonne is joined by three other major rivers: the Ariège, the Tarn, and the Lot. Just after Bordeaux, the Garonne river finally meets the Dordogne, after which the two rivers become the Gironde estuary, which after approximately 60 miles joins the Atlantic Ocean. Other tributaries include the Save and the Gers.
The Garonne is one of the few rivers in the world that exhibit a tidal bore. Surfers and jet skiers can ride the tidal bore at least as far as the village of Cambes (70 miles from the Atlantic) and even further upstream.
The Garonne plays an important role in inland shipping. The river not only allows seagoing vessels to reach the port of Bordeaux but also forms part of the "Canal des Deux Mers", linking the Mediterranean Sea to the Bay of Biscay, allowing a shorter and safer way for goods to pass from the agricultural areas of the South of France to the Atlantic.
From the ocean, ships pass through the Gironde estuary until the mouth of the Garonne (to the right of the Dordogne when sailing upstream). The Garonne remains navigable for larger vessels up to the "Pont de Pierre" (Stone Bridge) in Bordeaux. River vessels can sail upstream to Castets-en-Dorthe, where the Garonne Lateral Canal (Canal Latéral à la Garonne) joins the river. The lateral canal takes the ships through 53 locks to the town of Toulouse, where the canal meets the Canal du Midi, the next stage of the "Canal des Deux Mers".
The Garonne Lateral Canal was subject to one of the largest infrastructure works in Europe, when it was adapted to the standardized barge size of 38 by 5 meters, during the last century. French minister Freycinet ordered that all major canals used for long distance transport be suitable for vessels of those standard dimensions. The extension of all of the former 30 meter locks to the new standard length was carried out throughout the lateral canal. The other half of the Canal des Deux Mers, the Canal du Midi, partly escaped this operation, because by the time the works had reached the area where the most locks were situated, commercial traffic on the canal had almost disappeared. The works were stopped, leading to the cultural heritage status of the United Nations that has made the Canal du Midi famous. (Source: NoorderSoft Waterways database)