The ENVIBASE-Project

Documentation / Online Handbook

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Description of the Problem

Water and water resources have always played a crucial role in the history of the transformation of land in the Milan area. The first stage of the process involved transforming the countryside into agricultural land in the twelfth century thanks to a water distribution system with a network of irrigation canals.

In the second place, the Industrial Revolution wouldn't have been possible without technical advances in manufacturing and transport media, but there is no doubt that these changes depended on the availability of power (first mechanical, then electrical) guaranteed by the existence of a vast and widespread water network.

The hydrographical system in the metropolitan area of Milan is characterised by numerous watercourses which cross the area, flowing mainly from north to south. The most important are the Ticino river, forming a natural boundary between the provinces of Milan and Novara; the Olona river, which flows down one of Lombardy's oldest industrial conurbations (the Olona valley); the Lambro Settentrionale River, which, en route, crosses some of the largest municipalities in the metropolitan area (Monza, Sesto San Giovanni, and the eastern side of Milan); and the Adda river, which separates the provinces of Milan and Bergamo. The other numerous watercourses are streams (Bozzente, Lura, Groane streams, Seveso, Molgora), which cross industrial areas and receive a considerable amount of domestic and industrial sewage.

Large irrigation canals also cut across the Milan area from east to west, such as the Villoresi, Martesana, Grande, and Pavese canals, and the Northwest Scolmatore canal, into which the waters of the Seveso, Groane, Lura, Bozzente, and Olona streams all flow before reaching the Ticino.

The hydrographical system in the metropolitan area presents two kinds of problems. First, the main problems have to do with the safety of the watercourses:

These problems are responsible for frequent flooding in the countryside and built-up areas near the rivers. This is due to over-development and the difficulties encountered in territorial planning, which has failed to respect the hydrogeological structure of the watercourses.

Secondly is the issue of the quality of the water. The condition of the hydrographical system is further aggravated by the poor quality of all the watercourses listed above. Campaigns to monitor the quality of the water, carried out by Milan's Provincial Authorities, revealed that the watercourses which were monitored as part of the campaign may be classified according to the degree of pollution, i.e.:

Man-made watercourses are less polluted but are not free from risks. The main cause of pollution is faecal coliforms; this is due to the fact that many towns located near rivers discharge their unpurified waste into the water, as the sewage plants have never actually been built. The most remarkable example of this is the municipality of Milan's failure to provide a water conditioning complex.

Metal pollution, typical of industrial waste, has been detected mainly by monitoring stations situated in the north and north-east parts of the metropolitan area, namely in areas with the highest concentration of industry.

The water-bearing strata of the metropolitan area has a radial structure with concave and convex cone-like areas in central and northern parts as well as channels and subparallel areas in the southern part.

The deep depression which characterised the site of the city of Milan up until the end of the nineties, caused by the enormous concentration of private and public wells, is slowly filling up due to the closure of numerous manufacturing facilities.

Having receded for decades, the bed is now beginning to rise alarmingly (the bed rose some eight metres from 1991 to 1996), causing serious problems in the city's subsoil.

The groundwater is very deep in the northern area, reaching up to sixty metres, with the exception of the river beds where it is no more than a few metres deep. The depth of the groundwater diminishes progressively until the water resurfaces, giving rise to an area of springs, mainly in the southern area.

In the Italian legal system, responsibility for water resources is shared by a number of different bodies.

With regards to groundwater, ever since Regional Law n. 62/85 came into effect, the province of Milan has set up a groundwater information system (Sistema Informativo per la Falda - SIF) which organises and processes all the data supplied by researches on the quality of groundwater and sources of pollution and by the bodies responsible for managing and supervising the use of groundwater (USSL, Drinking Water Consortium, municipalities). This has made it possible to arrive at a complete picture of the pollution scenario based on present knowledge, with the further aim of improving the management and scheduling of land reclamation work according to available resources.

The approval of law n.183 of 1989 on environmental preservation has led to changes in the responsibilities for planning, managing, and controlling watercourses, constituting the basin's authority .

A further step forward was taken with the passing of law n. 36/94, which has the objective to ensure that the entire water cycle is governed by a single body. The most important initiatives currently underway in the province of Milan are in the area of planning and scheduling work relating to the entire water cycle. In accordance with the Regional Purification Plan, in the field of water purification, the prime objective is to raise the standards of watercourses currently classified as "polluted" so that they meet category D requirements.

Concerning the Waterworks Provincial Plan, despite continuous emergencies in the province of Milan and following incidents of groundwater pollution resulting in well closures and water shortages, other rich sources of good quality groundwater have been located that can supply drinking water to other areas during water shortages (these are so-called "water factories").

Data Sources

In view of the different responsibilities of the authorities, the data currently available on the condition of surface and subsurface water are held by numerous bodies, namely:


At present, no specific methodology is used to process the data available. Data is processed and organised according to the individual requirements of the various organisations (public bodies, management bodies, research centres).


The most important operating results involve groundwater data and are available from the province of Milan SIF information system (Groundwater Information System). In particular, it is possible to consult: maps showing where pollutants are to be found in the water-bearing strata, surveys of public and private wells with data on analyses, databases on the piezometric variations in the underground strata. With regards to surface waters, publications are available from the Province of Milan's Ecology Department and contain the results of surveys conducted to determine the characteristics of watercourses above ground.


The data available, in the form of tables, graphs, and maps, are used mainly for:

Results Analysis and evaluation methods Data
inventory maps / cadastral register Complex summarising / interpolation maps reference area / resolution / scale analogical / digital result calculation steps and spatial depiction main parameter Other necessary data Temporal distribution of data collection survey unit scale
Watercourses   Metropolitan area of Milan
Digital map base CTR
Analysis of the most important parameters Water levels and
Flow rates of the
  water level:
1 day measurement
1 representative measurement point for each watercourses
Quality of surface water   Metropolitan area of Milan hard copy Analysis of the most important parameters
Evaluation of measuring values applying own classification
Representation of 3 quality classes
Oxygen minimum/ Saturation
Faecal coliforms
Heavy metals
  6 measurements per annum
1 representative measurement point for each watercourses
Quality of groundwater   Metropolitan area of Milan
hard copy Analysis/choice of the most important parameters
Evaluation of measuring values applying drinking water standards
Organ-halogen Compounds
  Monitoring program
Public wells
Depth of groundwater   Metropolitan area of Milan
hard copy   Terrain level
Groundwater level
  Groundwater level
from 1987
1 value/year
Public and private wells
Groundwater use   Metropolitan area of Milan hard copy Analysis of available dates Volume extracted   Annual quantity
Public and private wells

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