Rain is very scarce, but the canals supply ample water for cultivation and all other purposes.
Canals lead from Milan to the Ticino, Adda and P0.
Numerous canals intersect the district, affording ample means of irrigation.
Alkmaar is a typical North Holland town, with tree-lined canals and brightly coloured 17th-century houses.
On the west side, however, there are the remains of several canals or channels, some still carrying water, one of which, the Shattel-Hai, leaving the Tigris at Kut-el-Amara, and emptying into the Euphrates at Nasrieh, is still navigable.