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Lake Borello, or Stagno di Oulx, is the only wet area in Val di Susa: since 1995, it has been an oasis for the protection of the rich ecosystem and commonly hunted animals.

The pond derives was created by filling a clay quarry which was used to supply construction material for the Frejus Tunnel (1861-1871).
After that, the basin was also used to produce ice; along with a similar facility in Salbertrand, the middle and lower Valle di Susa would receive a steady and abundant supply of ice.
In the 1930s, ice production and agriculture disappeared completely, thus the basin slowly filled up and naturally evolved to become the current pond; it is now surrounded by extensive reeds (Phragmites australis), peat bogs and hygrophilous meadows dominated by the presence of Carex spp ., and Eriophorum spp.

Forest vegetation is made of strips of Scots pine woods (Pinus sylvestris) and mesophilic broad-leaved trees; willows, viburnums, and Prunus padus grow in the undergrowth.

In 1974, following some research by Professor Mondino, the pond of Oulx was included in a list of natural areas of interest; this important recognition was mainly due to the presence of rare species (especially in Susa Valley and western Piedmont Alps) like:

– Epipactis palustris, an orchid identified by Pignatti in “Flora of Italy”, extremely rare in the Alps; it prefers humid grassland and swamp environments, as well as fresh soil with basic reactions in the mountain and on the hills;

– Frangula alnus, a deciduous shrub of the Rhamnaceae family, which is found mainly in humid environments and along the edges of forest formations, as well next to ditches and canals;

– Molinia coerulea, a heliophilous species found on sandy or peaty soils;

– Allium scorodoprasum, a Liliacea extremely fond of dry drained soils;

– Salix repens, a creeping willow typical of alpine peat bogs, which grows well in very humid soils; quite rare in the Alps, it has found a perfect habitat around Lake Borello;

– Schoenus ferrugineus, extremely rare in the Susa Valley, it grows well in the swamps and shallow bogs – possibly subacid.

This post is also available in: Italiano (Italian)