The 2GW connection will bring mainly wind power generated in the north of the country to west and south Germany.
Amprion said the surveys should provide information on how the nearly 90 waters – rivers, lakes and small streams – could be crossed with the underground cable route.
There are two possibilities: either an open cable laying through the water, or closed construction under the water, the company said.
A-Nord sub-project manager responsible for cable construction Ludger Jungnitz said: “In order to comply with the minimum distances between the riverbed and the cable system, we are already looking at crossing points to specify the route planning.”
The link is still in the middle of federal planning, which should ultimately see the federal network agency approve a 1000-metre wide corridor for the cable, Amprion said.
A decision should be made by the end of next year, eventually reducing the final route to 24 metres wide.
Construction is expected to start in 2023.