Il Lacus Turni ed il Lacus Juturnae due laghi scomparsi della provincia di Roma

Abstract

The lakes whose toponym is linked to the mythical character Turnus (Turno) and to that of his sister, the nymph Juturna (Giuturna), are two, places a few kilometers from each other and both in the province of Rome. The first lake, near Pavona village (Albano) with the current toponym of "il laghetto (pond)”, was known and well documented in antiquity as Lacus Turni. It was then indicated in historical cartography with the name "Lake Giuturna" or Lacus Juturnae or “lake of Castle Savelli". This lake was reclaimed by Pope Paul V in 1611. The second lake, known only from the historical cartography following 1660 with the toponym "Lacus Turni" or "Lake of Torno”, was located on the border between the territory of Rome and that of Pomezia, in the locality of Macchia della Capocotta it disappears from cartography in the mid-nineteenth century. About it was completely lost the memory as well as location. The first lake has origins well known, develops in the upper Pleistocene after the phase of volcanic activity that has determined the depression (maar) that hosts it. This lake is documented from the historical point of view and finds a precise geomorphological connotation. The second lake is set on the deposits of the Pleistocene medium p.p. of the Castelporziano Unit "red ancient Duna " Auct., on the highest of the sea terraces that border the Roman coast. About it currently remains only a small pond, partially reclaimed that, in the past, it was to be fed by some sub-lacual springs so as to originate an emissary (Rio Torno or Rio Turnus) flowing towards the coast near Torvaianica village. The analysis of historical cartography and historical-archaeological data, integrated by the analysis of the geological and eomorphological context in a GIS environment has made it possible to clarify many aspects of the evolution of these lakes. About the lake of Pavona the hydraulic context has been better defined as connected to the egulation of its waters in Roman era and its subsequent reclamation. About the Lake of Pomezia was able to proceed to a its precise location. In addition, its subcircular shape, the original arrangements, the structural context and stratigraphic as well as the presence in the area of significant gaseous emanations, both cold and hot, have suggested that its origin could be compatible with a sinkhole, similar to what happened for many other small lakes and sinkhole ponds present in the Lazio territory.