In Portugal, most of the population lives in urban areas and almost all cities have developed around rivers. Rivers in cities, called urban rivers, and their riparian woodland can provide important services to human populations, such as helping to maintain air temperature and humidity, contributing to lessen the effect of temperature extremes and climate change, mitigate urban floods, contribute to the improvement of air quality, to carbon sequestration and reduction of the greenhouse effect, improve the appearance of cities, constitute natural green areas that can be used for leisure and sports activities, improving human health, and constitute biodiversity reserves and can also be used by migrating species such as some birds.

However, urban development has taken a heavy toll on urban rivers and streams that have been artificialized, channeled, polluted or buried over time. As a result, their ecosystems have been largely degraded and the benefits they could provide are compromised.

It is therefore urgent to recover urban rivers, streams and their ecosystems. This is a priority at European level, which fits within the broader concept of returning nature to cities and the United Nations Sustainable Development Goals.

The implementation of measures to recover urban rivers and make cities more natural systems depends not only on scientific knowledge, but also on the recognition of this need by the population and politic groups as well as their active participation in this process.

That is why the CRESCERIO project was developed between 2018 and 2022 with a pilot class from the Solum Basic School with the main objectives of:

• Make the riverside ecosystems known, in particular the urban streams of the city of Coimbra, to the school community (children, teachers, parents, and others) and encourage children’s contact with nature;

• Make the biodiversity of urban streams known and analyse their main threats;

• Foster contact with scientific activities related to the ecological assessment of rivers (collecting samples of fauna and flora in the field and identify organisms with scientific optical instruments and calculate their quality indices);

• Develop social responsibility for the preservation and recovery of urban rivers and their ecosystems through the school community.