Val di Chiana

Provinces: Arezzo (AR) and Siena (SI)

Situation

The Val di Chiana, the valley of the River Chiana, extends southward for some 70km/45mi from Arezzo to Chiusi.

Topography

The Val di Chiana is the natural continuation of the Upper Arno Valley, which in prehistoric times drained into the Tiber but was later compelled by the build-up of soil deposited by the Arno's tributary streams to turn northwest. Some of the water of the Chiana (the Roman Clanis) continued to flow south, producing the rare phenomenon of a river dividing into two. The valley then degenerated into fever-ridden marshland, until it was drained in the mid 18th century and became one of the most fertile regions in Italy. The Tuscan Chiana discharges its abundant flow of water into the Arno by way of the Canal Maestro, while the Roman Chiana (generally called the Chiani) flows into the Paglia, a tributary of the Tiber, at Orvieto.