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Val Calnègia and the Foroglio Waterfall

The footprint of the glaciers

Svizzera, Cantone Ticino, CEVIO

Positioning

Foroglio

COORDINATES
(CH 1903) E   685371 N   136386 H   681.0
(WGS 84) Long.   8.548 Lat.   46.373
GENERAL EVALUATION
DIFFICULTY E-T2/T3
SCIENTIFIC INTEREST PRIMARY:
Glacial morphology

SECONDARY:
Hydromorphologie
OTHER INTERESTS Ethnographical, Landscape, Hiking, Archaeological, Architectural
Naturalistic, Didactic
GEOSITE   GEOMORPHOLOGICAL - glaciers

DESCRIPTION

The homes in Bavona are elegantly gathered in clusters around a few strips of land in a valley of long, flat tracts which are disturbed in places by frequent deposits of debris at the foot of the slopes. This main feature of the valley is in contrast to the extensive watery meadows below the walls, which are almost vertical for most of its length. Some lateral valleys have cut into the rocky sides, creating deep, narrow gorges which run down to the bottom. However, in this charming picture there is something exceptional. The side valley which branches off upstream of the Terra di Foroglio in fact has a “U” shape very similar to that of the main valley, but with a fundamental difference: its outlet is located 200 metres above the valley floor. The difference in height between Val Calnegia and Val Bavona is partially filled by short rapids and debris which the Foroglio Waterfall forcefully pours down upon.

INSIGHT

The geomorphological origins of Val Calnègia and the Foroglio Waterfall must be placed in close relationship with the glacial dynamics of the whole of Val Bavona. The geometry of the relief is in fact largely determined by shaping undergone by the slopes during the glaciations of the Quaternary Period. The typical trough shape of the profiles of Val Bavona and Val Calnegia is often wrongly considered to be a pure glacial form. In fact, it is the result of joint action between the processes of fluvial and glacial erosion. The lifting of the alpine chain has resulted in the direct definition of a hydrographic network responsible for a primary and constant deepening of the valley grooves. Only beginning in the Pleistocene Epoch, when there was a lowering of the average temperature, did the ice spread over the alpine caps, occupying the river valleys and flowing down to the plains south of the Alps. In this context, from 1.8 million years ago until about 13,000 years ago, the glacier originating from the region of Robièi repeatedly occupied the axis of Bavona, scraping and shaping the sides and bottom, which only later was partially filled by morainic, fluvial and gravitational debris. The bedrock of Val Calnègia, on the contrary, is visible at the end of the valley. At Puntìd, the Calnègia River carves the rock before hurling itself from the step which connects it with the Foroglio Waterfall at Bavona. The significant difference in height with respect to the valley is mainly due to the different size of the glaciers which have passed through, as well as to the importance of the preliminary fluvial erosion. The catchment area of Val Calnègia is, in fact, smaller than that of the wider and deeper Val Bavona.

CURIOSITIES

Underneath the boulders which have tumbled down the slopes, man has ingeniously made space for a number of shelters which are defined as “splüi”, “grondan” or “cantine”, depending on their architecture and function. In Val Calnègia, shortly after Puntìd (coordinates CH 1903: 684,640 / 135,660), you can observe an exceptional case: the “Splüia Bèla”. This giant boulder was split into several parts due to its violent impact with the ground, creating a living space for shepherds as well as a large shelter for their animals.
scala temporale periodi geologici

HOW TO REACH THE SITE

From exit 47 of the A2 motorway (Bellinzona Sud), proceed in the direction of Locarno. Follow the A13 until the exit for Vallemaggia after the Mappo-Morettina tunnel. Once in Vallemaggia, continue for another 23 kilometres until Bignasco where, turning to the left, you head towards Val Bavona. After a further 6 kilometres, you come to Foroglio, which has a large car park.

USEFUL INFORMATION FOR THE VISIT

To reach Puntìd, the entrance to Val Calnègia, take the path from the village of Foroglio. This takes you towards the valley in about half an hour.

TO LEARN MORE

AA.VV. (2004): Vivere tra le pietre. Costruzioni sottoroccia, Museo di Valmaggia, Armando Dadò, Locarno, 370 pp.
COTTI G. et al. (1990): Introduzione al paesaggio naturale del Cantone Ticino.Vol. 1, Le componenti naturali, Bellinzona, 484 pp.
GROSSI P (2008): Crosa. Coll. Laghetti alpini della Svizzera italiana, Op. 14, Centro di dialettologia e di etnografia, Bellinzona.
ZAPPA F. (2006): La Val Calnègia... tra dirupi e pietraie. Coll. Sentieri di pietra, Vallemaggia Turismo.

http://www.vallemaggia.ch/

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Programma di cooperazione transfrontaliera Italia - Svizzera 2007 - 2013 Progetto cofinanziato dal Fondo Europeo Sviluppo Regionale (FESR)
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