Avenc de les Granotes

A small rise of just under 2 metres, which via a low passage communicates with a pit of about 15 metres with walls lined by flowstone. At its base, in a Southerly direction, a short gallery with a low ceiling communicates with another pit of about 20 metres of drop. In its lower section a window communicates laterally with another hollow with a blind dome and whose lower end remains flooded for about 10 metres.

Returning to the base of the entrance pit and heading North, a stalagmitic flowstone is climbed and one enters a new vertical section, highly broken up, of about 25 metres of drop and which, as in the other route, reaches a flooded level.

A short way from the start of this second route, a window gives access to a series of short galleries and small pits that descend to about 40 metres of depth from the entrance level.

Walls lined by flowstone. Stalagmitic flowstone at the base of the entrance pit.

The underwater exploration of the two flooded levels confirmed that the water comes through infiltrations from the water table, entirely impenetrable. It seems more than likely that they shared the same water table and that it is also the one that appears in the cova del Centenari.

The first visits were made by members of the ERE – CEC in 1955. On 11 June of the same year, together with members of the GES – CMB they carried out the complete exploration and the survey.

At the same time, the ERE of the CEC explored a small cavity located on the other side of the hill, right next to the road, where after descending 2 metres they found a flooded pit with the same characteristics. It was named avenc de les Granotetes. It disappeared shortly afterwards due to widening of the road.

This suggests that the survey carried out in 1955 (we know of no other) is somewhat exaggerated, since we have been able to verify that the real height of the entrance is 40 metres above sea level.

We have news of some exploration around 1998/99 by members of the GE Pedraforca resident in Castelldefels and by the owners' own son, and it seems that inside there is a presence of carbonic gas.