The rain water and the carried one from the rivers, in case of necessity, was gathered in cisterns or depots digged in natural surfaces and reinforced with stone. There are circular or square depots located in the courtyards of private houses or in the squares of the blocks for a communal use as this arranged with a crossroads that keeps yet the channel to gutter the water on its inside.
In the crossroads we can see how the city was planned to defend itself from the North cold wind realizing the joint of the several parts of the terraced streets to block the air. The big stones located in the centre of the street helped to pass from a sidewalk to another without getting muddy since house drains were in the streets.
