The Nature Reserve covers a surface area of 162 hectares between Carignano and Carmagnola. Its name derives from the name of a meander of river Po which was abandoned during the flood of May 1977. In the oxbow, today almost completely filled with earth, many bird species find shelter, favored by a rich and characteristic marshy vegetation consisting of Reeds, Cattails, Sedges, Alders, Willows, and Black Poplars. The presence of a colony of Bee-eaters in the area is of considerable importance. Downstream, with the scientific advice of experts working for the local Natural History Museum, the Municipality of Carmagnola has created in 1987 Gerbasso Woodland: it is a "didactic" example of the ancient and huge plain forest which covered in the past the whole Po Plain. Gerbasso Woodland covers 19 ha and includes a willow grove, a oak-hornbeam grove, and some meadows. This stretch of river Po is characterized by the presence of the largest gravelly shores existing upstream Turin. Ad the edges of the Nature Reserve there area big quarry lakes which, when they will no longer be exploited, will be recovered with naturalistic, didactic, and recreational purposes, creating around them didactic routes, cycle facilities, and structures for the observation of nature.
Lanca di San Michele Special Nature Reserve is safeguarded not only by the establishment law of River Po Park, but also according to the regional law no. 47 of 3rd April 1995 "Norme per la tutela dei biotopi", the Decision 85/338/CEE of 27th June 1985, and the Directive 92/43/CEE of 21st May 1992, since it has been considered as "ecological entity of great interest for the conservation of nature" and therefore subject to the environmental-landscape regulations according to law 8th August 1985, no. 431 and the European regulations, recognizing it as SCI – Site of Community Importance (code IT1110024).