This natural lake, fed by a thermal spring, is the most important naturalist and archaeological site in the Euganean Hills
The Lago della Costa extends along the southeast side of the Euganean Hills, in the valley at the foot of the hamlet of Arquà Petrarca. Embedded between the slopes of Mount Calbarina and Mount Ricco, it appears as a wonderful sheet of blue water, surrounded by the nearby woods and the dark peaty plain emerged from the marshes from the mid-sixteenth century, thanks to the drainage led by the Retratto di Monselice (reclamation of swamps). It can be reached either descending from the Borgo del Poeta, east direction, or driving south on the provincial road n. 72 connecting Monselice to Galzignano: near the crossroads that leads to Arquà in fact here starts the path set up by the Park Authority and marked by special signboards.
Its relevance from both naturalist and archaeological points of view, definitely represents the main reason for visiting this lake site, whose dimensions were much larger in ancient time. Today, the shore appears practically abandoned, the vegetation is typically represented by marsh plants with prevalence of reed-beds and willows. The area is also interesting as we may observe several species of the local fauna, especially waterfowl, amphibians and fish.
Moreover, a thorough study of the deposits on the lake bed allowed the reconstruction of paleoclimate and palaeography of the territory: an accurate analysis of fossil pollens managed to identify the botanical associations dating back to the late-glacial era until the Iron Age (about 10,000 years ago).
The ancient origins of the lake
The origin of the lake Costa is ancient indeed and in prehistoric times the site was already attended by the first inhabitants of the Euganean Hills. Thanks to several artifacts found on its banks, it became one of the most important archaeological sites in the area. As a matter of fact, between the eighteen and the sixteenth centuries BC, at the beginning of the Bronze Age, this small body of water housed a wide lake-dwelling settlement, marked by circular huts. Later it was abandoned during the Mid Bronze Age (XVI from XV century BC.), likely because of events related to climate change. The finds recovered during divers excavations (fragments of ceramic pottery, bone-horn artefacts for the practice of hunting and fishing, the remains of worked fossil wood), can be observed today in the National Archaeologic Museum of Este as well as in the archaeological section of the Civic Museums of Padua.
The thermal waters
The lake Costa is fed by a thermal spring of hot water that flows on the end of a small peninsula that juts out into the center of the reservoir. Once few trickles of cold water coming from the nearby mountains contributed to ensure the water supply. However, the gradual drying up and exploitation of rivers for agricultural use, have implied that the lake is now fed almost exclusively by the thermal spring. For this reason, the extension of the water is variable and is gradually decreasing.
In the past both thermal water and muddy seabed made the lake suitable for the extraction of valuable therapeutic mud used in the spas of Abano and Montegrotto. Today muds are mainly extracted from the nearby pond of Lispida, which is also fed by springs of sulphurous waters that have acquired heat thanks to the well-known geothermal hydrological circuit.
Legends and stories of Lago della Costa
Several legends related to the lake della Costa have been handed down over the centuries. All of them fantasize about the smoke exhaled by warm lake water that during the winter and in the darkness of night evoke the presence of evil spirits. The most famous legend, taken by the writer Silvia Rodella in her book "Euganean Legends" tells us that in an unspecified time, instead of the lake here stood a monastery of friars, whose conduct was inequitable. One day a beggar knocked on the convent door and the only good-hearted little monk welcomed him. One of the following nights, the generous little friar was convinced by the beggar with an excuse to leave the monastery, which was suddenly struck by a violent storm that destroyed it completely, killing all the sinners inside. In correspondence of the rubble, a chasm opened and swallowed the impure souls and wiped out forever the remains of the monastery. The reservoir was then filled with boiling water fed from hell where sinners lie.
Currently the lake is visible from the road that runs along its eastern flank and from the paths of the nearby mountains. In fact its banks are enclosed by a network and to access it visitors must ask permission to the owners, because now the area is privately owned. The fence is necessary because in the past some local residents drowned while taking a bath, probably because of the depth of the reservoir quite profound at its center.
Thanks to its high naturalist and historical value, since 2011 the lake della Costa has been recognized as a site of Community interest and inscribed on the UNESCO World Heritage lists along with other pile-dwelling sites in the Alps.
A few steps from the lake, always at Costa, we can find another source of thermal water, the so-called Fonte Raineriana (Ranieri Source). In 1829, in order to protect and ease its use, the Archduke Ranieri of Austria built an artifact similar to a Roman temple, whose function was to celebrate even the healing powers of the water flowing here. The elegant neoclassical building was designed by the famous architect Giuseppe Jappelli. The small temple was demolished in 1932 and rebuilt a few years later, in 1938, by Adolfo Callegari, who took care to get a faithful reproduction of the nineteenth century model.
A marble plaque with a Latin inscription, placed outside the source, recalls the merit of the Archduke for having funded studies on sulphate-carbonate water intended to validate its therapeutic benefits. Today, the former source is relegated to the side of the square used as a parking lot of a restaurant-pizzeria; the water has almost completely dried up, however approaching the temple visitors can still feel the characteristic smell of the thermal water rich in sulfur.
Iniziativa finanziata dal Programma di sviluppo rurale per il Veneto 2014-2020
Organismo responsabile dell'informazione: GAL Patavino.
Autorità di gestione: Regione del Veneto
- Direzione AdG FEASR Parchi e Foreste -