Abstract

Acea is one of the main Italian multi-utility companies and leader in Italy in the water sector. With the aim of preserving drinking water to be distributed and of protecting the biodiversity in the areas surrounding water sources, Acea developed a semiautomatic change identification and classification system through satellite detection. Using satellite observation technique which diversifies spatial resolution (from 20 cm to 50 m) and time steps (from 1 month to 1 year) the Company obtains the best possible results in terms of protection of the natural resources.

The Experience

Acea Ato 2, the operating company of the Acea Group providing water services across a large area of central Latium, including Rome, is also responsible for monitoring areas where sources supplying drinking water to approximately 3.7 million inhabitants lie.

The ecosystem service - provision of drinking water - standing in these areas features a wealth of priceless natural resources and is therefore also particularly fragile.

With a view to maintaining value - thereby preventing any form of offence and damage preserving at the maximum level possible the natural resources involved, including biodiversity (strongly tied to the care of efficient ecosystem services) - the area surrounding the sources, totaling 6 million square meters (600 hectares), is subject to “total protection”, in accordance with the safeguard plan (Italian Decree 152/2006) and benefits from a thorough control and monitoring process.

This process provides a fundamental support to the early analysis of changes in land use. In particular, remote monitoring allows the prompt measurement and detection of any changes occurred in the intended use of land, in those areas under protection.

As a result, in addition to traditional on-site control operations conducted by its own staff, Acea Ato 2 has resolved to develop a semiautomatic change identification and classification system through satellite detection.

The satellite allows images to be first captured across the territory at different times and then compared, highlighting any changes occurred in these timeframes, as well as the extent and type of any such changes.

By relying on IT tools and complex mathematical algorithms, satellite images can be compared down to the smallest detail, with the option to record every change and develop a change map showing both changed and unchanged items.

The software is also equipped with appropriate reporting features showing, among other things, the classification of the extent of the changes detected according to the degree of criticalness pertaining to the nature of the recorded event.

As showed in the model on Image 2, the input images to the system go through various phases:

• an ingestion preparatory phase that consists of extracting metadata representing some specific characteristic of the images;
• a pre-processing intermediate phase, that executes geometrical co-registration, radio metriccalibration and georeferenced procedures;
• change detection phase that represents the core of the system.

The change detection algorithm is based on the mining of two spectrum images, complementary between each other, that measure the change occurred between two optical remote detected images, through the analysis of the spectrum signature of each pixel/shape of the image.

The block model that implements the above described change detection algorithm is showed on Image 3. As it can be noticed, the spectrum features, once calculated, are jointly developed through a categorization process, whose aim is to produce a change map, that is a classification map where only two classes appear, of which one represents the changed objects and the other the non-changed objects.

The following image 4 shows the application interface that gives an element very useful for the analysis: the comparison between the change map obtained through the algorithm and the image visible of the scene under observation.

By diversifying the spatial resolution (from 20 cm to 50 m) and time steps (from 1 month to 1 year), depending on the level of attention required by law (Italian decree 152/2006) and by the internal company’s procedure established to safeguard sources, according to their criticality and vulnerability, it is possible to reach a very high level of control and protection on the field.

Water is one of the main natural resources on earth and represents Acea’s core businesses.

If such important resource is affected in some way, it will not be available for all the services Acea offers to the territory and the flora and fauna living in the same land would also be damaged.

With the satellite monitoring, the possible changes, either due to human activities or to natural events, are promptly detected. Without such a system, as it was before year 2010, and only with in situ checking activities, the probability of missing some of the dangerous changes from the ecosystem point of view would be much higher. Any possible misuse of the land, such as illegal constructions, is identified.

With satellite monitoring it is possible to “see” the new building being constructed (or any other change) starting from early evidences through different colors that would result from the images taken by the satellite system.

In 2014, after the first experimentation, the following numbers were obtained:

• 90 image analyses had been conducted;
• 45 change maps had been verified;
• 5 suspect situations had been identified.

Analyses conducted to date have shown how satellite monitoring activity can actually represent a major supplement to “ground” control, allowing expected improvement goals to be attained, including a more accurate and timely detection of criticalities and, as a result, a more appropriate planning of protection actions.

The experimentation can be improved by trying to get a larger number of images per year and photos with higher resolution.

A positive effect in terms of streamlining of human resources has also been reached; some of the staff is dedicated to this task of image analysis and to check on site any problems encountered while other employees can be devoted to different important activities.The organizational impact has been relatively soft, being the most important effect of new procedures related to the substitution of field inspection activities (low skilled people) with a more interesting IT stream, leading towards a higher level of professional skills.

Finally, the advantages in terms of time saved and targets met can be underlined: being the territory very large, without the satellite system it would be almost impossible to check every area. Awareness of company’s employees, particularly among technicians, about the importance of environment protection activities, has increased in consequence of such technological innovation.

On one hand financial resources needed to the implementation of IT tool are quite important and till now wholly in charge of Acea, on the other hand, economic positive feedback is foreseen for the reduction of operative costs due to the saving of the staff work. Last but not least, a decrease in financial implications is envisaged due to the expected reduction in restoration activities thanks the availability of the IT tool that can intercept land abuse before they happen.