Eider Canal Eider Canal The Eider Canal (also called the Schleswig-Holstein Canal) was an artificial waterway in southern Denmark (later northern Germany) which connected the North Sea with the Baltic Sea by way of the rivers Eider and Levensau. Constructed between 1777 and 1784, the Eider Canal was built to create a path for ships entering and exiting the Baltic that was shorter and less storm-prone than navigating around the Jutland peninsula. In the 1880s the canal was replaced by the enlarged Kiel Canal, which includes some of the Eider Canal's watercourse. The canal's watercourse followed the border between the duchies of
Geology of the Baltic Sea on the Baltic water body became the Yoldia Sea. About 10,700 years ago the continued land rise separed the Baltic water body from the ocean again and Yoldia Sea turned into the Ancylus Lake. This lake lasted until 10,000 years before present when a new connection to the ocean was established, this time in the Danish straits forming the Littorina Sea. Land rise did not close off Littorina sea but it made its connection the ocean over time more shallow allowing less salt water to enter it, thus gradually it evolved into the current Baltic Sea with somewhat brackish water.