Leonardo, Milan and water

«Water is, among the four elements, the second least heavy and the second least stable. It never has any rest until it reaches its maritime element […] It rises voluntarily by the cause of heat into delicate vapor within the air. The cold freezes it; stability corrupts it. […] It takes every odor, color, and flavor, and of itself it has nothing.»
Paris Manuscript C, f. 26 v.

During the nineteenth century, with the arrival of railroads and the subsequent invention of internal combustion engines, transportation on rails and on roads was facilitated, which resulted in an increasing diminution of the importance of the canals as a system of transportation and communication. The inner canal network in Milan began to raise worries about hygiene because of its putrid waters. After it ceased being a privileged transportation route, it even became a sort of obstacle to the expansion of the city.

The Canals after Leonardo

In 1480, a few years before Leonardo arrived in Milan, the Florentine Giovanni Ridolfi highlighted the industriousness of the city, its «excellent artisanship […] in every art. » It was filled with hydraulic wheels, which were used for “fulling textiles, preparing paper, sawing lumber, striking metal, grinding grain.” Closed within its circle of canals, Milan utilized the defensive moat system, constructed between 1157 and 1158, to irrigate fields, for the movement of hydraulic wheels, and for navigation.

The many drawings in Leonardo’s codices prove how his interest for hydraulic works and for water were but a single aspect of his method of observation and representation of landscapes; at the same time, this representation made use of points of view that were equally artistic, naturalistic, and engineering.

Study of nature

«Before proceeding, first I will undertake some experiments,», noted Leonardo, when he decided to apply himself to improving the hydraulic works. Among the canals of Milan, the one to which Leonardo dedicated the greatest attention was the Naviglio Grande (Grand Canal).
The Canal is worth 50 gold ducats, it produces 125 thousand ducats a year, and it is 40 miles long [71.4 km] and 20 braccia wide [11.9 m] ».

Leonardo displayed a great interest for works of practical hydraulics, especially for the constructions of the Canals and the resistance of their banks.
«No canal that flows out of rivers will last if the water of the river from which it arises is not completely enclosed, as in the Martesana Canal and the one that flows out of the Ticino [the Naviglio Grande].(il Naviglio Grande).»
Codex Atlanticus, f. 184 v.

Study and survey of the waterways and canals

The duchy’s waterway system, with its small ports and its depots, permitted Milan to receive at low cost the various materials in arrival: stone, lime, grain, iron, and especially lumber, compensating for the lack of any large river.
Leonardo made observations and surveys relating to the water vessels on the canals.
«The largest boats made are 71/2 braccia wide [4.5 m] and 42 braccia long [25 m], with sides 11/2 braccia high [0.9 m]. »

Purpose of the canals

Based on his observations and surveys of the locks used in Milan, Leonardo described (or projected?) some improvements, such as the design for the graduated levels and introducing a hatch below, to be included in the corner doors.
«It is necessary to connect the Canals that do not tend to flow forward to low places, to where the water falls through the hatch of lock. Then, when the water arrives there, it will fall through this hatch among the other water, then fall into the boat and immediately fill it and submerge it. »

Perfecting the Locks

After Filarete’s project for Sforzinda, an ideal city in honor of Francesco Sforza, Leonardo, as well, was fascinated by the idea of planning a city as a formally complete organism.
The waterways are as important as the streets, but «if you want this to have effect […] you must choose an appropriate site, for example, placing it next to a river that will provide you for canals … ».

The Ideal City

During his stay in Vigevano, the city favored by the Sforzas, Leonardo described an ingenious project for reclaiming marshy lands, to be executed using water.
The “ladder” at Vigevano was initially used for reclaiming land and subsequently for bearing water to an irrigated meadow on a steep slope: it was a construction of great interest in terms of the techniques of reclaiming and irrigation.

Irrigation systems and land drainage

During the French domination, Leonardo studied two canal tracts in order to complete the navigational route between Milan and Lago di Como, which was already available from Trezzo sull’Adda to Milan via the Martesana Canal, but impracticable through the tumultuous tract of the Adda corresponding to the Gola di Paderno.
In a sketch illustrating the Brianza lakes, the Lambro, and the final part of the Lago di Lecco, Leonardo took considered a canal that would lead from the lake to the Lambro and from there to Milan. Though this hypothesis was immediately rejected, it has the merit of having presented Lombard cartography with the first image of the minor lakes, which until that time had been completely ignored on maps.

Observation of the lands

During 1506 Leonardo received the commission of projecting a new residence for the governor of Milan, Charles d’Amboise.
This commission offered Leonardo the opportunity to study the Nirone and the Fontelunga, the two watercourses that delimited the chosen area.
The small derivative canals were to have been used for feeding the ornamental waterworks for the “garden of delights” and for taking away discharge waters.

The Garden of Delights and Drawbridges

After Leonardo’s death, his studies and proposals for the Canals were taken up again by other engineers. The Paderno Canal, which initially had been financed by Francois I, was projected by Giuseppe Meda, the painter and highly capable engineer, during the second half of the sixteenth century. The numerous technical and economical problems interrupted the works, however, around the end of the century.
The work was terminated in 1777 through the initiatives of the Austrian government.