Description
Part of the gorge is also visible from the bridge on the municipal road leading to Povo, located at the northern end of the section of direct interest. The stretch of gorge that is the subject of restoration work includes two characteristic waterfalls created by artificial 'greenhouses' (Vecchia Serra di Ponte Alto to the north and Serra Madruzzo, to the south), the construction of which can be traced back, at least as far as the first interventions are concerned, to the first half of the 16th century (1537), commissioned by Prince-Bishop Bernardo Clesio to limit the damage caused to the city by the flooding of the Fersina torrent.
Among the works worthy of mention are a long spiral staircase carved into the rock in the second half of the 19th century (currently not equipped with a lighting system) and an impressive terminal waterfall (Serra Madruzzo) about fifty metres high, both visible in the second part of the film.
GEOLOGY
The gorge has the appearance of a veritable 'canyon' and is about 100 metres deep and varies in width, in the middle and lower stretches of the incision, from about 10 to 15 metres, with a slightly sinuous course determined by progressive fluvial erosion over time and variations in the speed of the current. The incision is excavated almost exclusively in the Scaglia Rossa formation, represented by red slab micritic limestones (layer thickness 5 - 15 cm), sometimes flinty, with marly interlayers, and marls (Upper Cretaceous; Turonian -? Palaeocene). Only in the basal part and further upstream of the gorge has fluvial-torrential erosion brought to light the lower rock formations, represented by Maiolica and Rosso Ammonitico Veronese and consisting of micritic limestone and reddish nodular limestone, well stratified, with ammonites (Upper Jurassic; Upper Bajocian - Upper Barremian).
ACCESS
Access to the "Orrido di Ponte Alto" Geological Site is near the hamlet of Cognola, about 3.5 km east of Trento, along the former S.S. n. 47, a few metres south of the junction leading to Povo and is easily reached by car.