Additionally, it seems the canal is a distinct diagonal shape that breaks off from the Elbe river, why not start the canal near Hamburg and then finish it nearby in Lubeck? This seems to be a shorter and less labor intensive route.
Actually, there had been another famous canal around that area that connect River Elbe and River since the end of the 14th century: Stecknitz Canal. This waterway was a one of rare examples of canals with locks that controlled the water levels to facilitate the transfer of ships (linked to the picture of the canal lock in Wikipedia), and it had played an important role for Lübeck merchants to transfer the salt from Lüneburg both to the Baltic and to the North Sea (via Hamburg) at the heyday of the Hanseatic League. The canal had been essentially the predecessor of now Elbe-Lübeck Kanal (or Elbe-Trave Canal) that would be constructed in the end of the 19th century (1895).
On the other hand, the modern Kiel Canal also had its predecessor, though dated back only to the 18th century, Eider Canal that connected the Wadden Sea in the West with the Baltic Sea. In short, Kiel Canal in the 19th century re-used some of its waterways, not built from a scratch.
Then, why [ex-]Eider Canal was preferred to [ex-] Stecknitz Canal as a course of the new (?), actually renovated waterway by the emperor? I'm not so well versed in the 19th German history, but some previous research suggests the money was the issue.
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