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River IJssel (IPA: [ˈɛi̯səl]), sometimes called Gelderse IJssel (Gelderlandic IJssel) to avoid confusion with its Holland counterpart, is a 120 km long branch of the Rhine in the Dutch provinces of Gelderland and Overijssel. It flows north from the city of Arnhem until it discharges into the IJsselmeer ("Lake IJssel", until the 1932 completion of the Afsluitdijk known as the Zuiderzee). In medieval times the estuary of the IJssel was the Vlie. It is one of the three major distributary branches into which the Rhine divides itself shortly after crossing the German-Dutch border, the other two being the Lower Rhine and Waal rivers. The name IJssel is thought to derive from the Germanic i sala, meaning "dark water". The average discharge of the IJssel can change significantly. The average discharge has been stated as 300 cubic meters per second. This can be as low as 140 and as high as 1800 (not sure on this, citations needed).

Contents 1 The IJssel as the lower part of the Oude IJssel 2 The IJssel as a Rhine distributary 3 Tributaries and connecting canals 4 Delta 5 See also

The IJssel once was the lower part of the Oude IJssel ("Old IJssel", German Issel, literate German translation "Alte Issel"), a small river that rises in Germany and is now a 70 km long tributary of the IJssel, merging with the main IJssel at Doesburg. The connection between the Rhine and the IJssel was probably artificial, being dug by men under the Roman general Nero Claudius Drusus as a defence against Germanic tribes and to let Roman shipcarry troops along it. The current Oude IJssel has been, after the Rhine, the main contributor of the flow of the river until today. The source of the Oude IJssel is near Borken in North Rhine-Westphalia, Germany. First it flows south-west until it nearly reaches the Rhine near Wesel, then it turns north-west. After Isselburg it crosses the border with the Netherlands (province Gelderland). It flows through Doetinchem and joins the IJssel in Doesburg.

From the moment the connection between the Rhine and IJssel was dug, the Rhine became the largest contributor to the flow of the IJssel, although only a relative low amount of the total Rhine flow is making its way into the IJssel system. Various tributaries can sometimes add quite some water to the total flow of the IJssel river, fore example the Berkel and the Schipbeek. The IJssel river is the only branch of the Rhine Delta that is taking up tributary rivers rather than giving rise to distributary ones.

The latter only happens at the very last stretches of the river, where the relatively minor IJssel Delta is created. Most of the Delta branches has been dammed up to lower the risk of major floods. Several of the delta creeks are, however, still connected without interruption. Of course this is a severe contrast with times long gone, the times before the Zuiderzee with high tides was converted to the shallow, fresh and tide-less waters of the IJsselmeer, severely diminishing the reach and potential build-up of the delta.

This all suggests that the IJssel is more or less a river in its own right. Although it's been fed by the Rhine, it still contains a lot of its own character as being a river that, although distributing a part of the Rhine outflow, still manages to be a river system that is retaining its distinct character. A river that is perfectly able to function on at its own, even without the inflow of Rhine water.

The following canals and tributary streams connect to the IJssel:

• Apeldoorns Kanaal (west) near the town of Dieren
• river Oude IJssel (east) at the city of Doesburg
• the Berkel stream (east) at the city of Zutphen
• the Twentekanaal (east) between Zutphen and the village of Eefde (municipality of Gorssel)
• the Schipbeek stream (east) near the city of Deventer
• the Grift stream (west) at the town of Hattem; its lower reaches have been channelised to form the mouth of the Griftkanaal
• the Willemsvaart canal (east) at the city of Zwolle
• the Zwolle-IJsselkanaal (east) near Zwolle

Near the city of Kampen, the river IJssel flows into the IJsselmeer through a small delta, the branches of which are called, west to east, Keteldiep, Kattendiep, Noorddiep, Ganzendiep and Goot. Of these, the Keteldiep and Kattendiep channels are the main navigational arteries; the Noorddiep has been closed off at both sides.

The Delta is partially shared with the river Vecht, which flow as the Zwarte Water (Black Water) into the Zwarte Meer. This lake could should probably be included in the IJssel Delta.

Railroad bridges (with nearest train station on the left and right bank):

• between Arnhem Velperpoort and Duiven
• between Brummen/Klarenbeek and Zutphen
• between Apeldoorn and Deventer
• between Wezep and Zwolle

• Hollandse IJssel