thanks to @amapanda river maps I found the German river Altmühl is not mapped correctly.
Problem is, the Main-Donau-Channel and the Altmühl are kind of the same in the lower part starting at Dietfurt an der Altmúhl to when the river flows into the Danube. In the lower part the name is Main-Donau-Kanal. How can this be solved? It seems one can not enter two names for the same line.
See https://waterwaymap.org/#map=11.97/48.96354/11.6929&tiles=planet-grouped-ends


