| Swist | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Germany |
| Subdivision Type2: | States |
| Subdivision Type3: | Reference no. |
| Subdivision Name3: | DE: 2742 |
| Source1 Location: | Near Kalenborn (bei Altenahr) |
| Source1 Elevation: | ca. |
| Mouth Location: | Near into the Erft |
| Mouth Elevation: | ca. |
| Custom Label: | References |
The Swist is a stream, long, in the German Rhineland. It rises on the northern edge of the Eifel at 330 metres above sea level and empties from the right and southeast into the Rhine tributary, the Erft, between Weilerswist and (a district of Erftstadt). Occasionally the Swist is also called the Swistbach, and locals often just call it der Bach ("the stream"). The Swist flows through the municipality Swisttal, the town of Meckenheim and Flerzheim. There are cycle paths by the side of the stream along this stretch. The Swist gave its name to Swisttal and the town of Weilerswist. Its source area is situated at the northern edge of the Eifel.
Its source lies at in the northern part of the Eifel in the Ahr Hills, north of the village of Kalenborn in the collective municipality of Altenahr in the county of Ahrweiler. The Swist has an average gradient of 5 ‰ and flows initially to Vettelhoven (Grafschaft) in a northeasterly direction and then descends at a gradient of just 1.3 ‰ through the Fore-Eifel. It continues along the western slopes of the hill ridge in the börde landscape of the Rheinbach Loess Plateau through Meckenheim, Flerzheim, Morenhoven, Heimerzheim and . At the Swist empties into the Erft between Weilerswist and Bliesheim.
Its catchment area lies between that of the Rhine near Bonn and its smaller tributaries like the Hardtbach or to the northwest and that of its parent river, the Erft around Euskirchen right in the west and peters out quickly towards the north-northwest. It is rural and, in the open country, arable fields predominate. Around the upper courses of the stream and its especially along its important left-hand tributaries there is a large contiguous forest as well as pastures and meadows. The largest part of the catchment belongs to the state of North Rhine-Westphalia, the source region is in Rhineland-Palatinate.
The most important tributary of the Swist is the Steinbach, which joins from the left at river kilometre 15.7 as the Jungbach. Between and Essig it bears the name Orbach. The 20.5adj=midNaNadj=mid stream has a catchment of which is about 17% that of the Swist. The tributaries of the Swist are listed below.
| Name | Position [km] | Location | Length [km] | Catchment [km<sup>2</sup>] | Mouth height [m. ü. NN] | DGKZ | |
|---|---|---|---|---|---|---|---|
| Kahlenborner Bach/Swistbach | 42.939 | right | 0.6 | 2742 112 | |||
| Buchenwaldbach | 42.407 | left | 1.0 | 2742 114 | |||
| Nonnenbach | 39.185 | right | 2.2 | 1.950 | 2742 12 | ||
| Bach von Alteheck | 38.103 | right | 1.5 | 1.262 | 2742 132 | ||
| N.N. | 35,251 | left | 1.1 | 2742 134 | |||
| Unnamed stream | 32;660 | left | 1.7 | 2742 136 | |||
| Unnamed stream | 31,899 | right | 1.4 | 2742 138 | |||
| Essigbach | 29.680 | left | 5.9 | 7.629 | 182 | 2742 14 | |
| Mühlengraben/Spießgraben | 29,334 | right | 1.4 | 4.405 | 178 | 2742 16 | |
| Altendorfer Bach | 28.585 | left | 10.0 | 11.534 | 176 | 2742 2 | |
| Ersdorfer Bach | 27.247 | left | 7.5 | 5.267 | 170 | 2742 32 | |
| Morsbach/Wormersdorfer Bach | 24.692 | left | 6.7 | 12.342 | 161 | 2742 34 | |
| Unnamed stream | 22.675 | right | 3.1 | 155 | 2742 392 | ||
| Mühlengraben | 19.088 | right | 2.1 | 146 | 2742 394 | ||
| Eulenbach | 19.066 | links | 12.3 | 23.059 | 146 | 2742 4 | |
| Wallbach | 17.589 | left | 8.9 | 22.600 | 143 | 2742 52 | |
| Steinbach/Orbach/Jungbach | 15.717 | left | 20.5 | 48.227 | 140 | 2742 6 | |
| Buschbach | 13.482 | right | 8.2 | 21.965 | 134 | 2742 74 | |
| Schießbach | 12.676 | left | 13.7 | 16.627 | 132 | 2742 8 | |
| Mühlengraben | 12.141 | right | 1.6 | 131 | 2742 912 | ||
| Uhlshover Graben | 12.01 | left | 1,8[1] | 131 | |||
| Kottengrover Graben | 11.485 | right | 0.7 | 0.736 | 130 | 2742 92 | |
| Kriegshover Bach | 9.733 | right | 4.2 | 8.042 | 127 | 2742 94 | |
| Müggenhausener Fließ | 3.999 | left | 5.2 | 11.846 | 113 | 2742 96 | |
| Weilerswister Mühlgraben | 0.675 | left | 2.9 | 107 | 2742 992 |
Originally the River Ahr flowed in what is now the riverbed of the Swist. After the uplifting of the Ahr Hills, and its route northwards was barred, the Ahr tried to find a way directly to the Rhine.
In places it is said that the Swist is the longest stream (i.e. German Bach, small river) in Europe[2] This probably goes back to when its course was marked by wide meanders in the area of the low gradient between Vettelhoven and its mouth. Since the straightening of the Swist in the early 20th century and certainly no later than its canalisation in the 1960s it has probably lost this record.
The Roman aqueduct to Cologne crossed the valley of the Swist between Meckenheim and Rheinbach on an arched bridge which was 1,400 metres long and up to 10 metres high. Archaeologists have worked out that the bridge must have once had 295 arches with an inside width of . Nothing is left of the structure apart from a low strip of rubble. In Lützermiel the foundations of a Prussian bridge have survived. The bridge once carried the district road (Bezirksstraße) from Bonn to Schleiden, built in 1823, over the Swist.