habitat rupestre.pdf - Società Friulana di Archeologia

THE INFLUENCE OF GEOLOGICAL AND GEOMORPHOLOGIC ASPECT IN THE REALIZATION OF ARTIFICIAL CAVESCRHIMA-CINP projectFig. 8 A panoramic view of the Lake Nemi near Rome (photo: C. Germani).Fig. 9 Meskendir Valley (Cappadocia – Central Turkey). The millenarianerosion in an artifi cial drainage tunnel has caused the remodelling of thecross section: the original section is suspended on the vault of the cavity(photo: G. Bologna - Centro Studi Sotterranei ). In this case, the remodellingis caused also by the exfoliation.conditioned by the difference in elevation between the sourceand the final destination (Castellani, 1999). This granted theright water load for public and private fountains.During the Spanish vice – Realm, at the end of the 17th century,human settlements in the high Neapolitan districts hadwaters from wells, also because ancient aqueducts had not thenecessary water loads (Fiengo, 1990). The subterranean hydrogeologicalassessment plays a primary role for the realization,the stability and the preservation of an underground work(Delle Rose et al., 2006). The underground water circulationis an important conditioning aspect during the realization andthe fruition of the work. It is function of primary and secondarypermeability of each rock formation. In case of lithoidrocks, the presence of draining or plugging fractures can createserious risks of flooding and impossible fruition (Fig. 6).In other situations, deepening the mines can bring to interceptthe water table, with the evident necessity of lowering itthrough pumping out waters; if this solution is not economicallyconvenient, works will be abandoned. If the richness ofthe deposit brings to lower the piezometric surface, the undergroundworks will be totally submerged at the end of the extraction(Fig. 7). The control of lake levels and the reclaimingof marshy areas are very important hydraulic works. The possibilityof restoring unhealthy and marshy lands has alwaysbeen a determining aspect for the realization of emissaries, asin the Lakes of Nemi (Castellani & Caloi, 2000; Castellani etal., 2003), Albano (Castellani & Dragoni, 1989), and Fucino(Burri, 1987; 2005).There are many geological and structural factors that affectthe distribution of springs and their discharge, depending onthe subterranean catchment. Their quality is important for thecaptation and the transport of waters through aqueducts.If walls and the bottom of these works are not properly covered,after years of abandonment they can be remodelled bythe erosion of water. Water searches for a natural base profileby means of re-incisions at the bottom (Bertucci et al., 1995;Cappa, 1999), while the original sections are abandoned at thetop (Fig. 9). These are very particular speleogenetic features,where the formation of a natural cavity in rocks (not necessarilykarst rocks, as tuffs or cineritic rocks) is due to mechanicalerosion, which is induced by the pre-existence of an artificialabandoned cavity.Fig. 10 The rupestrian village of Zelve (Cappadocia, Central Turkey) was abandoned only in 1950 because of the risk of collapses (photo: R. Bixio - CentroStudi Sotterranei). The images show the same view: a great isolated pinnacle in 1985 is subject to erosion. In 1990 the pinnacle is already collapsed.volumeRicerca_OK_2012-11-15.indd 22 16/11/2012 15:00:46