From Wednesday divers will be searching the Hollandse IJssel near Oudewater for World War II bombs. The river needs maintenance between Gouda and Nieuwegein, and the water board wants to make sure that everything is safe before the work can begin, NOS reports.

Historical research shows that the river contains many WWII bombs that never exploded. As long as they are left alone, they are not dangerous. But part of the work that needs to be done to the river is dredging to keep it deep enough for barges. Therefore the bombs will have to be removed first.

The search for bombs is expected to take about five days. A research boat already mapped all metal objects in the river. Divers will now investigate them from close by, according to RTV Utrecht. The expectation is that most of these objects will be things like shopping carts, bicycles and traffic signs. Any bombs found will be rendered harmless. 

If all goes according to plan, the dredging will start on August 1st.