|Location:||East of the village Eprave, north of the show cave Han-sur-Lesse. Follow N86 from Han-sur-Lesse to Rochefort, at the end of Han-sur-Lesse turn left on Rue du Beau Séjour and then immediately right. At the end of the paved road you can see the rocks in the forest to the left.|
|Dimension:||Spring: 800 l/s.|
|Address:||Geopark Famenne-Ardenne, npo, Place Théo Lannoy, 2 - 5580 Han-sur-Lesse, Tel: +32-84-345172. E-mail:|
|As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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|1993||cave closed with a gate.|
The Grotte d'Eprave is named after the nearby village. The rocks were it is located ar a popular climbing spot, the top of the cliff offers a great view over the valley and the surrounding limestone hills, which are called Tiennes by the locals. The cave is located at the foot of the cliff, above the valley floor. There are stone steps leading to the cave. Only the entrance area of the cave is accessible. The inner part of the cave has nice speleothems and so the cave was closed by a gate in 1993 to protect the cave.
Below the cave is the resurgence of a cave river which emerges from the lower waterfilled level of the cave. The Eprave resurgence is a vauclusian spring and with an average discharge of 800 l/s it is the biggest in Belgium. The Wamme and Lomme rivers feeds several underground streams, flowing from north-east to south-west following the geological structure. In other words: the rivers are loosing water in their bed. From Rochefort the Lomme looses water, in dry periods the river vanishes completely from the surface and the river bed is dry, until the lost water reappears at the Eprave resurgence.
Middle Devonian limestones (Givetian Stage) are folded by the Ardenne orogeny and form a stripe on the surface. The limstone is bordered by the shales of the Nismes formation (Frasnian). This rock is not soluble and thus not karstified, so the underground water is "forced" to emerge at the Eprave exurgence.
The system of underground waterflows is currently examinated in the KARAG (Karst Aquifer Research by Gephysics) project. The scientists worked together with local cavers to place sensor systems in various caves which access to the water table, and a cave lab at Rochfort Cave was used for collecting data. The project uses geophysical methods like gravimetry which is recorded and analyzed with special software. If you are interest, they published the first dissertation online on their website, see the link below.