|Length||30 km (19 mi)|
The Oude Maas (Dutch pronunciation: [ˌɔudə ˈmaːs]) ("Old Meuse") is a distributary of the Rhine River, and a former distributary of the Maas River, in the Dutch province of South Holland. It begins at the city of Dordrecht where the Beneden Merwede river splits into the Noord River and the Oude Maas. It ends when it joins the Nieuwe Maas to form Het Scheur
The Oude Maas forms the southern boundary of the IJsselmonde island. Soon after Dordrecht the Dordtsche Kil forks off and after that the Oude Maas forms the northern boundary of the Hoeksche Waard island, flowing west until the Spui river forks off at the town of Oud-Beijerland. The Oude Maas then heads northwest between the towns/cities of Spijkenisse and Hoogvliet and joins river Nieuwe Maas opposite the city of Vlaardingen, the combined river is known as Het Scheur and flows to the North Sea.
The river is tidal and has nature and recreation areas.
The hydrological distribution of the Maas have always been subject to change. During the early Middle Ages the main flow of the Maas followed a path towards the sea that have now mostly disappeared, leaving the Binnenbedijkte Maas lake as only remaining remnant. In the 13th century a major flood forced the Maas to shift its main course north towards the Merwede river (which is the continuation of the Waal river, thus being part of the Rhine delta). From then on, several stretches of the original Merwede were named Maas instead and served as the primary outflow of that river. Those branches are currently known as the Nieuwe Maas and Oude Maas. For several centuries the Nieuwe and Oude Maas were considered part of the Maas delta. Near Vlaardingen, these two met and then split again at the island of Rozenburg: the north branch was known as Het Scheur and the south branch as either Nieuwe Maas or Brielse Maas because it flowed close to Brielle. Het Scheur and the Brielse Maas then met again to form an estuary known as Maasmond ("Mouth of Meuse").
However, during another series of severe floods the Maas found an additional path towards the sea, resulting in the creation of the Biesbosch wetlands and Hollands Diep estuaries. Thereafter, the Maas split near Heusden into two main distributaries, one flowing north to join the Merwede, and one flowing directly to the sea. This diminished the influence of the Maas on the Oude and Nieuwe Maas distributaries. The branch of the Maas leading directly to the sea eventually silted up, (and now forms the Oude Maasje stream), but in 1904 the canalised Bergse Maas was dug to take over the functions of the silted-up branch. At the same time, the branch leading to the Merwede was dammed at Heusden, (and has since been known as the Afgedamde Maas) so that little water from the Maas now enters the old Maas estaury, or the Rhine distributaries. The resulting separation of the rivers Rhine and Maas is considered to be the greatest achievement in Dutch hydraulic engineering before the completion of the Zuiderzee Works and Delta Works. Since then, the vast majority of the flow of the Oude and Nieuwe Maas come from the Rhine, and not the Maas.
Connections from the IJsselmonde island on the north:
- with Hoeksche Waard island:
- 1st and 2nd Heinenoordtunnel (motor vehicles, cyclists)
- with Voorne-Putten island:
- Spijkenisser Bridge (motor vehicles, cyclists, pedestrians)
- metro tunnel