Aachtopf (Aachquelle)
Germany's largest karst spring, at the town of Aach in the Hegau, fed largely by Danube water that seeps away upstream. Divers have followed the mostly water-filled passage about 400 m in a straight line from the spring pool, with only a short dry stretch in the 'Seenhalle', until a collapse blocks the way after about 600 m. Strong flow and murky water make it one of the hardest cave dives in the country, and it has only been roughly surveyed. In 2015 a cave diver discovered pale loaches here – the first cave fish known from Europe.
Facts
- Region: Germany – Mines & Caves
- Area: Swabian Jura & Baden-Württemberg
- Depth: 0–18 m
- Level: advanced
- Current: strong
- Type: cave
- Coordinates: 47.846444, 8.857889
- Highlights: Germany's largest karst spring, about 8,000 l/s on average, fed by Danube water seeping underground, underwater cave route about 400–600 m to a collapse, first European cave fish (a loach population found in 2015), sump
- Permit: According to the town of Aach, the Aachquelle may be dived only by experienced cave divers with permission (in practice Full Cave level certification and a cave-exploration team are needed); the spring has been a natural monument since 1939. The source does not name the issuing authority – start with Aach town hall. Check current status.
- Issuer / contact: Stadt Aach (Rathaus)
- Phone: +49777493090
- Email: gemeinde@aach.de
- Address: Hauptstraße 16, 78267 Aach
- Website: https://www.aach.de/de/Freizeit-Tourismus/Aachquelle
- Tips: Not a recreational site: no operator, no public access to the cave. Only experienced cave divers with permission; dives are realistic only at low discharge. The spring pool and its park can be visited from the shore. Check current status.