Multilayer blue-green roofs as nature-based solutions for water and thermal insulation management

Abstract

Green roofs have been widely recognized as sustainable nature-based solutions to mitigate floods in urban areas, which, in the last decades, are increasing due to the combination of intense worldwide urbanization and climate change. Besides flood mitigation, green roofs provide additional benefits for the urban environment (e.g., reducing the urban heat island and ensuring energy saving for the underneath building). Moreover, green roofs facilitate the increase of urban biodiversity, attracting different species of small animals, and upgrade the city aesthetic value. Among the different types of green roofs, multilayer blue-green roofs present an additional layer to store water during rainfall events. As part of the Polder Roof field lab project, prototypes of multilayer blue-green roof developed by the Dutch company Metropolder were installed in four Italian cities: Cagliari, Palermo, Perugia, and Viterbo. The four prototypes and the experimental set up are described and the potential benefits of this innovative solution are discussed. Preliminary analyses, from December 2020 to December 2021, enable to estimate runoff reduction and thermal properties of multilayer blue-green roofs, underlying the high potential of this nature-based solution, which allows to retain most of the rainfall events and to mitigate the daily temperature variability.

Drainage systems design in urbanized areas under land use changes scenarios: case study of Narok Town (Kenya)

“…The channel geometric properties were designed as an improvement to convey the estimated peak flow for both the investigated channels by increasing their crosssections. In order to overcome some of the limitations highlighted by the present study, future research should concentrate on: 1) improving the surveys of the river network, using also UAV devices that proved to be effective in flood risk management (Annis et al, 2020); 2) using bidimensional hydraulic models to map eventual flood prone areas; 3) introducing and testing blue-green infrastructure in urban drainage to mitigate natural capital losses and contribute to other forms of capital crucial for human well-being (Cristiano et al, 2022)…”

Sensing and Measurement Techniques for Evaluation of Nature-Based Solutions: A State-of-the-Art Review

“…As shown in Table 1, this systematic review indicates that the most researched NbS interventions include green roofs, green walls (e.g., [58,105,106]), urban vegetation, and street trees. Most NbS studies have primarily focused on single functions and a limited number of studies have focused on NbS efficacy evaluation post-implementation that are often restricted to a specific geographic region [25,107]. It should be noted that the most easily sensed and measured NbS functions such as air pollution abatement, temperature regulation, and storm water management have been the most widely researched [36,37,47,61,74,87,88,96,99,103,107,108].…”

Impact of the Innovative Green Wall Modular Systems on the Urban Air

“…The research studies on urban resilience contribute to the resilience assessment and sustainable storm water management in practical urban planning in a context of climate adaptation plans, and identify the environmental indicators that evaluate the outcomes of the metropolitan and local planning process and actions [22,23]. We analyzed many projects that can be used as a "green print" with a great potential use of green infrastructure in the regeneration of the cities, with multiple benefits ranging from ecosystem restoration and increased property values, to improvements in personal wellbeing, and these can serve as an effective climate change adaptation solution [24,25].…”