The Aniene River, the second-largest tributary of the Tiber after the Nera River, is 98.5 km long. Along its course, it flows through the territory of 17 municipalities, the last of which is the Metropolitan City of Rome. Near Tivoli, after a significant drop in elevation, it opens onto the Roman plain, running alongside the A24 motorway up to the outskirts of the capital. Within the city, it crosses Via Tiburtina, Via Nomentana, and Via Salaria before flowing into the Tiber near Via dei Prati Fiscali.

The river passes through territories that differ both environmentally and socio-economically, which results in a range of critical issues and needs that require careful attention.

In the upper and middle valley (up to the municipality of Tivoli), residential settlements are generally located at a distance from the river, with the exception of the towns of Subiaco, Vicovaro, and Tivoli. In the Roman countryside, due to its flat morphology, there is greater urban expansion along the riverbanks, which increases progressively as it reaches the municipality of Rome. The flat area upstream of the city is also characterized by intensive agricultural use, which needs to be monitored for its potential impact on water quality.

The abundance of its waters has historically made the Aniene a valuable resource for supplying the city’s aqueducts and, more recently, for powering hydroelectric plants that have significantly contributed to the industrial development of cities such as Tivoli and Subiaco.

After crossing the G.R.A. (Grande Raccordo Anulare), the Aniene flows entirely through urbanized areas until it joins the Tiber. In its final urban stretch, it is fully protected by the Aniene Valley Nature Reserve, which, with its 620 hectares of green space, is the fifth largest natural reserve within the Municipality of Rome.

The river represents an important ecological corridor for plant and animal species along the north-eastern axis of the city.

Unlike the Tiber, the Aniene — with its vegetated banks — is subject to less effective monitoring and control of degradation along its shores. It is therefore essential to activate a virtuous mechanism of community involvement in monitoring conditions of environmental degradation along the river, including the periodic mapping of the most critical points.

Between 2022 and 2023, through the “RomaUP” project, it emerged that pollution is widespread along the entire course of the Aniene, from the G.R.A. to its mouth. Seven chemical, physical, and biological parameters indicative of water quality were analyzed: ammonia, Escherichia coli, phosphates, nitrates, electrical conductivity, pH, and turbidity. At all sampling points, the values were found to be significantly above critical thresholds for most of these parameters.

For this reason, it is important to integrate additional data, especially when such data can be collected with the involvement of people living in the area. This involvement not only contributes to greater ecological awareness, but also enables people to take an active role in knowledge production, generating reflections on the practices to be implemented and proposed to political decision-makers.

The project involves a participatory environmental monitoring campaign of the waters of the Aniene River, carried out through field activities, training sessions, local networking, and advocacy. The initiative builds on and continues the work carried out over the past two years in collaboration with the association A Sud, aimed at protecting the Aniene and Tiber rivers and their ecological systems.

To provide concrete support to those working to safeguard this valuable ecosystem, the participating associations have deemed it essential to continue monitoring water quality in the river’s urban stretch and to extend sampling to the upstream, extra-urban section beyond the Grande Raccordo Anulare, up to the Tivoli area, where several environmental criticalities are present.

Citizen science activities involve the direct participation of activists, residents, and local associations in field data collection, scientific validation, and the dissemination of results. The aim is to foster open and accessible dialogue among civil society representatives, academics, technical experts, and institutional actors around some of Rome’s key environmental challenges.

The section selected for sampling activities is the final stretch of the river (approximately 25 km), from the municipality of Tivoli, passing through the G.R.A., to the point where the Aniene flows into the Tiber within the urban area of Rome, near Via Salaria.

Duration: 2023-2024
Coordinator: Insieme per l’Aniene Aps
Partners: A Sud, Retake Roma Sacco Pastore, A.D.A., Roma Adventure ASD
Beneficiaries: 120 activists, 120 school students and 2 schools
Funding: Periferia Capitale Programme, Fondazione Charlemagne