Grotte della Baix Ebre

The Baix Ebre brings together 188 catalogued cavities, of which 105 are pits and 83 are caves. The whole totals 18705 metres of surveyed passage and a maximum depth of 283 metres. The predominant lithologies are dolomites (93 cavities) and limestones (92), with a lesser presence of conglomerates (3).

Among the cavities most notable for their length are the Forat de Riu Algars, with 2000 metres of passage at Alfara de Carles (el Port), a drop of 43.5 metres and a meandering layout; the surveyed passage is 1190 metres. The Avenc de la Crisi, with 1215 metres, contains the largest vertical drop in Catalonia, at el Port (Tortosa). Other relevant cavities are the Avenc del Cim de l'obaga del Pollo, of 754 metres, and the Avenc dels Mamelons, of 700 metres.

As for depth, the Avenc Cp.6 reaches 283 metres on the S slope of Mont Caro (el Port), at the head of the barranc de Cova Pintada, and was explored by the Espeleo Club Tortosa from 1985. The Avenc Cp.1, with 195 metres of drop in the Cova Pintada sector (el Port), presents subhorizontal conduits, chambers and shafts down to the -179.5 level. Also notable are the Avenc del Camí de Xàquera, of 180 metres of depth at Tivenys (Baix Ebre), discovered and cleared by the GIE – CE Gràcia around 1972 or 1973, and reached by the UEC de Tortosa in 2014; and the Avenc dels Mamelons, of 167 metres of depth at the Mola de Catí (el Port, Tortosa).