The Naviglio Grande is a canal in Lombardy, northern Italy,
joining the Ticino river near Tornavento (23 km south of Sesto
Calende) to the Porta Ticinese dock, also known as the Darsena,
in Milan. It drops 34 m over 49.9 km. It varies in width from 22
m to 50 m from Tornavento to Abbiategrasso, dropping to 15 m
between there and Milan. Initially carries 63 m³ per second, 116
outlets take water to irrigate 500 square kilometres leaving the
canal 12 m wide and carrying 12 m³ per second as it enters the
dock. The Naviglio Grande was the first artificial canal in
Europe and the most important of the Milan “navigli”. Probably
originating as a ditch dug in 1157 between Abbiategrasso and
Landriano as a defense against Barbarossa, it was one of the
largest post-medieval engineering projects, allowing development
of commerce, transport and agriculture. In 1177, construction
began near Tornavento, but problems stopped work almost
immediately. In 1179 however, a dam was constructed and water
from the Ticino was directed