Erdbachhöhle

The Erdbachhöhle lies near Breitscheid in the eastern Westerwald, where the Erdbach stream vanishes underground in a series of swallets called Kleingrubenloch. The cave is set in a karst area formed from a Devonian coral reef, stretching roughly 100 m down from the surface. Water travels underground before reappearing 1.25 km east and 110 m lower as a strong karst spring west of Erdbach. The underground route shows varied flow times between 14 and 35 hours, with one flood event cutting the journey to just two hours. This points to a large, branching cave network with changing water paths. Measurements show the spring releases about twice the volume that sinks in at Breitscheid, so more tributaries must join the system. Known passages form a shaft-and-canyon pattern with little sinter decoration, and the cave remains partly unexplored and closed to the public. Explorers first entered in 1965 after a new swallet collapsed, mapping nearly 500 m and reaching 96 m depth within two years. After the entrance was sealed by floodwater, it reopened in 1991 and led in 1997 to a 1,000 m extension from nearby Schwinde C. A connection to the Erdbachhöhle was proved in 1999 through a siphon, making the combined Erdbach-Höhlensystem about 1,800 m long. It is the second-largest cave system in Hesse, lying only a few hundred metres from the Herbstlabyrinth-Adventhöhle-System.