134, Sima de la Porra la Altiquera (H-11), Pozu de la Altiquera. It is difficult to delineate both, the southern and the western boundaries of the system. For this reason it can not be determined where lies the divide between the areas drained by the Río Junjumia and the Río Redemuna.
The shortest, no more than 3 km long, is the system related with the Río La Beyera. It drains possibly a small, northern part of the exploration area. The southern limit of this system can not be precisely delineated, hence it can not be ascertained if the area of its influence reaches behind the line: Sierra Les Robeques - Porru Curelles. The base of erosion of this system lies at altitude ca 1100 m, where the waters surface on Vega Brical, and soon disappear in the active stream cave Pozo Palomberu, to reappear in the Río La Beyera. Accepting that the southernmost parts of the area have elevations close to 1600 m, we get the maximum vertical range of ca 500 m. In the initial course it is supplied, among others, from the east, from Vega El Forcau, by the known cave system Pozu de la Vega El Forcau. The western limit is difficult to draw in the discussed area.
Because of the difficulties in establishing the western boundaries of the systems related to the Río Redemuna and the Río Beyera, one can not exclude that a very narrow, eastern stripe of the exploration area is drain by the system related to the Río Casano. This system, directed to the north, is supplied in its southern part by caves Sistema Jorcada Blanca (F2/F7) and Pozu del Redondo (F20). The waters surface in the valley of the Río Casano in Hoyo La Madre. It is difficult to establish if the system reaches farther south, draining water from beneath Jou de Arenizas and, much lower, from the slopes of the Pico Conjurtau and Porru Cureles.
It will appear soon if the concept outlined above is correct. We are entering a new decade and a new century. The fourth decade of exploration in this part of the western massif of the Picos de Europa is before us.