Essentially water was collected from the seepage of rainwater and from springs in the hills surrounding Siena. The idea was to channel this water first to the city and then from one part of the city to another. Without modern instrumentation work on the Bottini tunnels was necessarily slow, with decades or centuries involved in the completion of various branches.
These ‘Bottini’, a name referring to the barrel vaulting of the underground galleries, follow the line between the porous upper level of limestone and the lower impermeable clay layer. Until 1914 this network and its fountains were the only source of water for Siena. That has changed as Siena's water now comes from Mt. Amiata, but still today the old network gathers water that feeds the fountains and wells throughout the city.
There are two principal branches of the system - one that carries water from Fontebecci to the large Fontebranda Fountain, the other, constructed in 1300, that feeds the beautifully decorated Fonte Gaia pool in Piazza del Campo as well as other smaller fountains.
Construction of the UNESCO-recognized Fontebranda fountain began at the end of the 13th C. and its three wide Gothic arches and adjacent open air pool illustrate a system of water usage common at the time: the first pool for potable water for the local citizens, a second (now filled in) serving as a drinking trough for animals, and a third set aside for washing clothes.
Water flowing through the underground canals fed mills, tanneries and dye-works throughout the city - one of the latter belonging to the Benincasa family of Saint Catherine. With the passing of centuries private citizens, tired of carrying water from wells and fountains, began to demand that their households be connected to the city's water supply. In the 19th century the amount they could take was based on how much they paid, this measured in 'dadi' - 1 dado corresponded to about 400 liters every 24 hrs. Plaques throughout the bottini make note of who was to receive how much.
And while water was eventually assured, the network had to be protected. There were severe laws prohibiting 'foreigners' from entering the tunnels, from cultivating above them or from stealing water for private use. From 1467 entrances outside the city walls were closed to stop enemies from breeching the city's defenses through its acqueducts.
Even now entrance into the tunnels is carefully guarded though guided tours in the spring and autumn can be organized (well in advance) through the “La Diana” association, which allow visitors to walk along the passageways where gathered rainwater flows along channels to public fountains or private wells.
Parts of the network have fallen into disrepair or calcification though it is the mission of the La Diana association to maintain the tunnels and keep the network alive in the minds of its citizens for the engineering marvel that it is.
The Water Museum, located at Fonti di Peschaia, 1, provides a multimedia presentation of this engineering feat and the role it played in the city.
If a visit is not possible, read a more complete history of the Bottini.
If you'd like us to organise a trip around these secret tunnels, ask us in plenty of time and we will do our best - though tickets cannot be assured!
