| Radolfzeller Aach | |
|---|---|
 Aachtopf, view from the Radolfzeller Aach source in the direction of the flow | |
 Map, with place names in Alemannic | |
| Location | |
| Country | Germany |
| State | Baden-Württemberg |
| District | Konstanz |
| Cities | |
| Physical characteristics | |
| Source | |
| • location | Aachtopf in Aach |
| • coordinates | 47°50′48″N 8°51′29″E / 47.84667°N 8.85806°E |
| • elevation | 475 m (1,558 ft) |
| Mouth | |
• location | into Untersee between Radolfzell and Moos |
• coordinates | 47°42′57″N 8°56′28″E / 47.71583°N 8.94111°E |
• elevation | 395 m (1,296 ft) |
| Length | 32.0 km (19.9 mi) [1] |
| Basin size | 255 km2 (98 sq mi) [1] |
| Discharge | |
| • average | 10 m3/s (350 cu ft/s) |
| Basin features | |
| Progression | Rhine→ North Sea |
| TVC | DE/2172 |
The Radolfzeller Aach (also known as Hegauer Aach) is a right or north tributary of the Rhine in the Hegau region, southern Baden-Württemberg (Germany). It is approximately 32 km (20 mi) long and drains into Lower Lake Constance. Most of its waters derive from the Danube river through the Danube Sinkhole.