Who would build a water bridge over a river?

It’s real. A 1km-long water bridge over the Elbe River in Germany joining the Elbe-Havel canal to the Mittelland canal near the eastern town of Magdeburg.
Who would build a water bridge over a river?

It’s real. A 1km-long water bridge over the Elbe River in Germany joining the Elbe-Havel canal to the Mittelland canal near the eastern town of Magdeburg.