Sardinia is the second largest island in the Mediterranean: it measures 24,089 sq.Km, and is located between 38°51'52" and 41°15'42" Lat. North and 8°8' and 9°50'Long. East.
This island, which is situated in the middle of the Western Mediterranean, lies just 12 km from Corsica, at a distance of 120 km from Tuscany and 185 Km from the North African coast. It is surrounded by shallow seas, and its coastline measures 1,849 Km in total.
The Sardinian coasts are generally high and rocky; the coast is however varied by articulated sections, with promontories and wide and deep bays surrounded by islets. Where the coast is low and leads to plains, the sea seems at times to reach inland by means of marshes, wetlands, sandy dunes. The coast is more rugged and broken in large sections in the north-west and north-east.
The geology of Sardinia is extremely ancient; its rocks date back to the Early Palaeozoic (300 million years); as a consequence, the island does not have high peaks, since its mountains have been levelled by long processes of erosion. The landscape is dominated by a rocky tableland of granite, schist, trachyte, basalt (locally known as "giare" or "gollei"), sandstone or limestone (called "tonneri" or "tacchi"), which range between 300 and 1,000 Mt. in height.
Among the mountain ranges, it worthy to be mentioned the Gennargentu - in the centre of the island (Flumendosa basin)- with its highest peak of 1,834 m., the mount Limbara in the north (1,362 Mt.) and the mount Rasu, the highest mountain in the "Marghine" range, which lies diagonally for 40 km also in the north.
These reliefs alternate with deep valleys and winding riverbeds. With the notable exception of the Campidano, a large plain to the south, which starts from the gulf of Cagliari and stretches for 100 km to the gulf of Oristano, in Sardinia there are few plains, usually of small extension.
Of the great forests of ilex, oak, chestnut and carob - which have been intensely exploited since ancient times - we find today ample remains which cover approximately one sixth of the total ground area for an extension of about 475,000 hectares. Particularly imposing is the forest of Gutturu Mannu, in the south, which is the largest in the Mediterranean.
There are three major rivers, both as to length and water flow: the Flumendosa, which flows into the sea in the southern part of the east coast, the Tirso which flows into the Gulf of Oristano and the Coghinas which flows into the sea in the north (Gulf of Asinara). We should also remember the Temo which flows into the sea at Bosa and is the only navigable river in Sardinia. Their waters have been harnessed and form artificial lakes. The main reservoir systems of Sardinia are reported in Figure 2‑1.
The waters which flow underground and appear as karst springs both in the open and in caves are also of great interest.
Equally important are the mineral springs flowing from fractures in the terrain due to ancient processes of volcanism dating back to the Tertiary and Quaternary; these waters have therapeutic properties and are also marketed in the form of mineral water.
The climate is generally mild and is influenced by the masses of air coming from the Atlantic, from Africa and from the Arctic.
The weather is generally good, over the year there is an average of 300 days of sunshine, with rain during the remaining period; the largest concentration of rainy days occurs during the winter and autumn, with some sudden showers in springtime.
The average temperature in July is 23.9°C while in January it is 11.1°C; average annual humidity is 70%. The island is swept by many winds - firstly by the mistral, a wind from the north west, which is fresh and piercing in the winter, and during the summer months mitigates the heat, making the air drier and more breathable.
Less frequent is the sirocco - which usually hits the western coast - and the north east winds which blow along the eastern coast.
Molentargius lagoon near Cagliari, a characteristic salt marsh and one of the most important wetlands internationally, succeeds in attracting an incredible concentration of birds, in spite of the encroaching city. Common water birds such as duck, waders and common species of marshland birds flock there together with gulls, and pink flamingos.
Not far from Alghero in northwest Sardinia lies Capo Caccia, a limestone outcrop dropping sheer for a hundred feet or so to the sea. This place is particularly known for its caves, especially Neptune's grotto, to which access is gained from the water or by a long flight of steps. Though the vegetation on the cape is somewhat thin, it includes a number of native species, some of them found nowhere else in the world.