The straightening of the Rhine by the Baden engineer Tulla shortened the shipping route between Basel and Worms by 81 km and better protected the country from flooding. However, this shifted the risk of flooding downstream and affected biodiversity. Starting in 1817, the first six cuts were made north of Karlsruhe. First, a guide ditch was dug, from which the river then carried out its own washing of soil until the new riverbed was formed and could be reinforced. At times, up to 3,000 day laborers were working on it at the same time. The Upper Rhine correction was not completed until 1876, after almost sixty years of construction. The straightening separated the area of the Rheinschanze near Mechtersheim from the Palatinate side. As compensation, Mechtersheim received the island of Flotzgrün, which is enclosed by the Berghausen Altrhein.