the construction of artificial shipping canals was necessary in the industrialisation period of the ruhr due to lacking transportation routes via capable, navigable rivers. the oldest part, the dortmund-ems canal, is connecting the eastern ruhr since 1898 with the north sea. in 1914 the connection to the rhine followed via the rhine-herne canal and the datteln-hamm canal was opened, too. in 1930 the wesel-datteln canal was finished. all these connected waterways need to bridge altitude differences between the starting point, the connected harbours and the arrival point. for these purposes there are today e.g at the rhine-herne canal 5 sluices and at the wesel-datteln canal 6 sluices; at the henrichenburg boat lift two ancient and two actually utilized sluices facilitate the bypassing of the altitude difference within the dortmund-ems-kanal to dortmund harbour.