51°43′50″N4°42′57″E / 51.730431°N 4.715881°E /51.730431; 4.715881
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TheRhine–Meuse–Scheldt Delta is ariver delta in theNetherlands formed by the confluence of theRhine, theMeuse and theScheldtrivers. In some cases, the Scheldt Delta is considered a separate delta to the Rhine–Meuse Delta. The result is a multitude ofislands,branches and branch names, in which awaterway that appears to be one continuous stream may have numerous separate names for different sections, e.g. Rhine →Bijlands Kanaal →Pannerdens Kanaal →Nederrijn →Lek →Nieuwe Maas →Het Scheur →Nieuwe Waterweg. Since the Rhine contributes most of the water, the term "Rhine Delta" is commonly used, although this name is also used forthe delta where theAlpine Rhine flows intoLake Constance. By some calculations, the Rhine–Meuse–Scheldt Delta covers 25,347 km2 (9,787 mi2), making it the largest in Europe.[1]
The Rhine–Meuse–Scheldt Delta is economically extremely important, since the three rivers are major navigablewaterways. The delta is the entrance from theNorth Sea to theGerman andCentral Europeanhinterland (and to a lesser extentFrance). Major ports in the delta areRotterdam,Antwerp (Belgium),Vlissingen,Amsterdam (through theAmsterdam–Rhine Canal), andGhent (through theGhent–Terneuzen Canal). The land areas in the delta are protected from flooding by the DutchDelta Works.
The shape of the Rhine Delta is determined by twobifurcations: firstly, atMillingen aan de Rijn, the Rhine splits into theWaal and theNederrijn, and secondly nearArnhem, theIJssel branches off from the Nederrijn. This creates three main flows, two of which change names rather often. The largest and southern main branch begins as the Waal and continues as theBoven Merwede ("Upper Merwede"), theBeneden Merwede ("Lower Merwede"), theNoord River ("North River"), theNieuwe Maas ("New Meuse"),Het Scheur ("the Rip") and theNieuwe Waterweg ("New Waterway"). The middle flow begins as theNederrijn, then changes into theLek, then joins the Noord, thereby forming the Nieuwe Maas. The northern flow keeps the name IJssel until it flows into LakeIJsselmeer. Three more flows carry significant amounts of water: theNieuwe Merwede ("New Merwede"), which branches off from the southern branch where it changes from the Boven to the Beneden Merwede; theOude Maas ("Old Meuse"), which branches off from the southern branch where it changes from the Benede Merwede into the Noord, and theDordtsche Kil, which branches off from the Oude Maas.
Before theSt. Elizabeth's flood (1421) theMeuse flowed just south of today's line Merwede–Oude Maas to the North Sea and formed anarchipelago-like estuary with the Waal and the Lek. This system of numerous bays, estuary-like extended rivers, many islands and constant changes of the coastline, is hard to imagine today. From 1421 to 1904, the Meuse and the Waal merged further upstream atGorinchem to form theMerwede. For flood protection reasons, the Meuse was separated from the Waal through a lock and diverted into a new outlet called the "Bergse Maas", then theAmer flowing into the former bay known as theHollands Diep.
The northwestern part of the estuary (aroundHook of Holland), is still calledMaasmond ("Meuse Mouth"), ignoring the fact that it now carries only water from the Rhine. This might explain the confusing naming of the various branches.
The hydrography of the current delta is characterized by the delta's main arms, disconnected arms (Hollandse IJssel,Linge,Vecht, etc.) and smaller rivers and streams. Many rivers have been closed ("dammed") and now serve asdrainage channels for the numerouspolders. The construction ofDelta Works changed the delta in the second half of the 20th century fundamentally. Currently Rhine water runs into the sea, or into former marine bays now separated from the sea, in five places, namely at the mouths of the Nieuwe Merwede, Nieuwe Waterway (Nieuwe Maas), Dordtse Kil,Spui and IJssel.
The Rhine–Meuse Delta is a tidal delta, shaped not only by thesedimentation of the rivers, but also by tidal currents. This meant that high tide formed a serious risk because strong tidal currents could tear huge areas of land into the sea. Before the construction of the Delta Works, tidal influence was palpable up toNijmegen, and even today, after the regulatory action of the Delta Works, the tide acts far inland. At the Waal, for example, the most landward tidal influence can be detected betweenBrakel andZaltbommel.
Already in the time ofJulius Caesar, the "Island of theBatavi" was known to theRomans. Its eastern point was the split of the Rhine into theOude Rijn and theWaal, which at this time were the two main branches of the Rhine. The Waal flowed into the Meuse in the Roman period.
Pliny the Elder'sNatural History gives a list of tribes living in the "Gaulish islands", within the delta region between different mouths of the Rhine. First, he mentions the large island of theBatavians and theCananefates. Then he gives the list of other peoples who he says are stretched out along 100Roman miles, between the mouth of theHelinius (understood to be the main mouth of theMeuse, where theWaal (Latin:Vacalis) also discharged) and the Roman fortification atFlevum (a port north of theOld Rhine).[2] The Romancastrum atFlevum was mentioned by Tacitus, and is equated today withVelsen.[3] Although the details are no longer clear, there was apparently sometimes an extension of the OldIJ that came close to the North Sea here.[4] But the term Flevo was also used byPomponius Mela to refer to thefresh water lakes which were in the area of the modernZuiderzee, which Mela specifically says that the Rhine fed into. So the Rhine mouth mentioned by Pliny might have been a discharge into a lake, or perhaps water running to Flevum on the coast may have run via the lakes to the coast, perhaps first through an ancient version of theVecht, or theIJssel. The IJssel however was joined to the Rhine artificially, byDrusus, and is quite far from any of the places known to be called Flevus.Suetonius says that this channel was still referred to asDrusus' fossa in his time.[5] Some authors have argued that the mouth Pliny mentions is theVlie, much further to the north than Velsen where the main waters of the lake entered the North Sea.[6]
There are actually fiveemissaries, namely:
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