Water security: the “new normality” of informal settlements. Nature-Based Solutions as sustainable mitigation and adaptation strategies

The COVID-19 pandemic showed us how fragile cities are when dealing with this phenomenon. The lack of green areas, high pollution levels, and human overpopulation contributed to the increase of the urban heat island effect and proved to be the perfect ingredients for the spread of the virus that changed, perhaps forever, our ways of living inhabiting. The consequences were even more dramatic for the inhabitants of informal neighbourhoods, as these exacerbated existing problems related to economic instability and low food and water security. This paper proposes using Nature-Based Solutions to mitigate and adapt to climate change and increase access to water in informal settlements. The research study focused on analysing two technologies, the Blue-Green roof and Rain Garden, developing a prototype for each one. Considering that the practice of self-building characterises spontaneous settlements, the modules were conceived to be built by the inhabitants using recycled materials. These low-tech strategies improve indoor thermal comfort, facilitate the storage of filtered rainwater for domestic use and provide access to affordable food through domestic scale cultivation. Implementing these solutions in marginalised neighbourhoods could also empower residents to face challenges related to Global Warming, such as runoffs generated by heavy precipitations, and improve hygienic conditions to prevent the spread of diseases.