The main stream of the Rhein river flows almost due west across Holland as the Waal river. The flow is unhindered by weirs or locks, all the way to the sea, forming the Rhine Delta in the Netherlands. A parallel, northern branch is the Neder-Rijn, which flows into other branches that are a busy highway for commercial barges and cruise ships. A large portion of the flow turns north at Arnhem on the Gelderse IJssel, into the IJsselmeer. Several ancient branches of the Rhein in the Netherlands continue the Rhein name (Rijn in Dutch): Neder-Rijn, Kromme Rijn, Leidse Rijn, Oude Rijn. The Oversteek bridge is shown above, at Nijmegen; note the water-level scales on each of the bridge supports, showing the range of possible flooding. Land has been opened on the north side of the river at Nijmegen to make room for flooding.