Nord-Ostsee-Kanal
The Eider remains tidal as far as the lock at Nordfeld, above Friedrichstadt. There is a further lock named near Wrohm, upstream of Nordfeld. A further beyond Lexfähre is the junction with the short Gieselau Canal, which provides a navigable link to the Kiel Canal at Oldenbüttel. The Eider therefore provides an alternative route from the North Sea to the Kiel Canal, avoiding the tides of the estuary of the Elbe.