The section between Basel in Switzerland and Bingen in Germany is known as the “Franco-German Upper Rhine”. Part of this section (from Weil am Rhein to Lauterbourg near Karlsruhe) forms the border between France and Germany.
A particular feature of the southern part is the large volume of water carried in early summer. Snow melting in the Alps means that much more water flows through this part of the Rhine.
Until the 18th century, the Franco-German Upper Rhine was a natural river with many branches and meanders. It was straightened for shipping and agriculture in the 19th century. Ten weirs with hydroelectric power plants are also located in this part of the Rhine. Most of the water flows through the man-made Alsace Canal, which runs parallel to the Old Rhine. This has changed the landscape significantly.
If you look at the map you will see that the Rhine divides between Basel and Breisach-am-Rhein. The left-hand section (the western side) is the Alsace Canal, and the right-hand section (the eastern side) is the Old Rhine. The orange squares are hydroelectric power plants. The fishes represent places where special fish-ladders have been set up to make it easier for fish to pass the power plants and other obstacles.