A. All stakeholders benefit fairly from the project

The ROOF WATER-FARM is an innovative demonstration site located in the heart of Berlin, near Potsdamer Platz, showcasing sustainable urban infrastructure that integrates wastewater treatment and food production. Situated in the "Block 6" quarter of the 1987 International Building Exhibition in Berlin-Kreuzberg, the site transforms wastewater and rainwater collected from nearby buildings into usable resources for farming and fertilizer production (Ref. 1). This project provides a real-world example of how sustainable systems can be incorporated into everyday urban design to enhance resilience and functionality.

At the ROOF WATER-FARM, water from rooftops and surrounding households is channeled into a treatment plant, where it is analyzed for micropollutants and purified. The treated water is then used for both fish farming in aquaponics systems and plant irrigation in hydroponic farming. The nutrient-rich water from the fish tanks nourishes plants, while also contributing to the production of food. This integrated approach actively supports climate protection by managing rainwater runoff and using plants for CO2 storage, helping to mitigate the urban heat island effect (Ref. 4).

This demonstration site embodies how cities can move toward a circular economy, where wastewater is reused for both farming and water management. The project also serves as a hub for learning and experimentation in sustainable urban design, with the greenhouse acting as a space for collaboration and innovation in infrastructure development (Ref. 2; Ref. 5). By incorporating these technologies into urban environments, the ROOF WATER-FARM demonstrates a future where buildings and neighborhoods efficiently recycle water, produce food, and reduce environmental impact.

“El Chamizal is a site of significant sociocultural importance and a key part of the identity of the people of Juarez. It is frequently visited by over 200,000 people seeking a space for recreation and enjoyment.” Located along the Rio Bravo/Grande river, El Chamizal is a park and a riparian area (Ref 2). Despite its popularity, the park has been suffering three decades of irregular management by the Municipal Government of Juárez and is facing issues such as accelerated desertification, soil degradation, and biodiversity loss. (Ref.2)

To counteract some of these challenges, in February 2024, the Secretariat of Environment and Natural Resources (Semarnat) and the National Commission of Protected Natural Areas (Conanp) designated El Chamizal Park, spanning 327 hectares, as a Zone of Ecological Restoration (ZER) (Ref 1).

The restoration plan involves dividing the park into four distinct zones, each with specific recovery actions (Ref 1; 2). Zone A, covering 107.3 hectares, is designated as a conservation area where reforestation with native species must commence. Zone B, which spans 47.8 hectares, also requires reforestation with native plants. Zone C, encompassing 12.7 hectares, consists of flooded or floodable plains that must remain in their current state. However, the surrounding ecosystem in this zone needs restoration with native aquatic plants to aid in stormwater purification. Zone D, at 159.8 hectares, contains existing infrastructure—such as buildings, installations, and communications—that must remain unchanged (Ref 3, p. 96). The project proposal is still awaiting implementation.

The Dreamy Draw Recreation Area is located in Phoenix, Arizona. It is situated near the Phoenix Mountains Preserve and provides access to various hiking and biking trails, as well as scenic desert landscapes. The Dreamy Draw Recreation Area project is a comprehensive initiative aimed at enhancing an existing park space. Key improvements include infrastructure upgrades, trail enhancements, and ecological restoration efforts. Through the construction of new ramadas, expanded parking, and increased accessibility features, the project seeks to create a more welcoming and inclusive environment for all visitors. This endeavor was launched as part of the City's Drought Pipeline Project.
One important component of the project is revegetation, which includes the planting of native saguaros to support ecological restoration and improve the park's visual appeal. The project addresses several longstanding challenges, such as limited parking, outdated facilities, and the need for improved trail conditions. By adding more parking spaces, installing modern restrooms, and constructing accessible pathways, the enhancements contribute to a safer and more enjoyable experience for visitors. Additionally, the revegetation efforts help restore natural habitats and mitigate the ecological impacts of urbanization on the local environment.
In total, more than two dozen mature saguaros were replanted in the newly reopened Dreamy Draw Recreation Area, creating an “immediate visual impact,” particularly along Route 51. The Mountain Parks and Preserves Committee held a meeting on Monday evening to review the revegetation work completed over the summer, with the area reopening on September 7.
Of the 58 cacti planted in this project, 27 saguaros—referred to as "reclamation saguaros" by Wayne Colebank, a landscape architect on the project—were previously stored by Phoenix Water Services at the 24th Street Water Treatment Plant near Lincoln Drive and 24th Street. (1-11)

According to the FAO, in 2022, 16.6 million Peruvians faced moderate or severe food insecurity, representing an increase of 1.5 million compared to the previous year (3). This situation was exacerbated by the health crisis, inflation, and job losses, leaving three out of ten Peruvians in poverty in 2021. The situation was particularly critical in Metropolitan Lima and Callao, with 14% of families reporting difficulties in acquiring protein-rich foods due to their precarious economic situation (2).
In response to this food crisis, the Municipality of Lima implemented the "Lima te Cuida" (Lima Takes Care of You) initiative, in which residents from vulnerable areas got training to create urban gardens and produce organic compost to help the community kitchens in these areas become self-sustainable (1, 2). An example of this initiative is the community garden in A.H. Villa Mosha in San Juan de Lurigancho, where a community garden has been built, and community members have been trained in small-scale planting, cultivation, care, and harvesting of various foods (2).
This initiative has been supported by the MUSA project "Mujeres Unidas por la Seguridad Alimentaria y Ambiental" (Women United for Food and Environmental Security) as part of the project "Alimentando a Lima desde Adentro" (ALDA) (Feeding Lima from within), which has had an impact in eight districts of Lima to strengthen food security (3). In addition to promoting urban agriculture, the project seeks to influence public policy through training and development of proposals to promote urban agriculture at the local level (4).

The GLAS Garden in Ballymun was established in 2011 by the NGO Global Action Plan, serving as a community-driven initiative that offers a welcoming and accessible space where people of all ages and abilities can engage with nature, learn new skills, and build connections within their community. The garden is actively utilized on a weekly basis by various groups, including St. Michael’s House, Saol Clubhouse, the Central Remedial Clinic, Ballark Youth Training, and Young Ballymun. It features a polytunnel for year-round growing, a whimsical fairy garden, and numerous microhabitats, including a pond, composting systems, a grow dome, and an innovative rainwater harvesting system made from recycled plastic bottles.
As part of the social regeneration program for Ballymun, the Green Living and Sustainability (GLAS) community garden has been operated by Global Action Plan (GAP) since its inception. It is supported by Dublin City Council under the Social Regeneration Fund and serves as a hub for environmental education and social inclusion in the area.
GAP’s GLAS garden brings together individuals of all ages and abilities, providing a socially inclusive space for participatory learning and active exploration of sustainability. It plays a crucial role in helping individuals and groups reduce their carbon footprint, produce organic food, and enjoy nature, thus transforming the garden into a space for positive change. (1-5)

The Belt Line Center building, located in Detroit, Michigan, property of Letts Industries, features a green-blue roof, along with a rain garden, showcasing the benefits of green infrastructure in historic properties. The idea for this retrofit emerged in 2015 after a major renovation, when Chip Letts, CEO of Letts Industries, recognized the potential of green infrastructure for long-term energy efficiency and storm-water management.
The initiative gained momentum in 2018, following the Detroit Water and Sewerage Department's (DWSD) introduction of new drainage fees, which charged $750 per acre of impermeable surfaces. The DWSD also offered up to 80% discounts for properties implementing green solutions, further incentivizing the project.
The project officially began in 2020 after securing PACE funding (Property Assessed Clean Energy funding, a financing mechanism that enables property owners to fund energy efficiency, renewable energy, and water conservation projects) from CounterpointeSRE (financial institution), marking the first use of commercial PACE financing for a green roof in Michigan. The green roof, covering 17,250 square feet, includes 300 square feet of pedestal pavers and a 2,500 square foot blue roof. These features enhance stormwater management, energy efficiency, and roof longevity; the center also incorporates two beehives to support local biodiversity.
These systems work in tandem with the ground-level rain garden to capture and infiltrate stormwater runoff, significantly reducing the impact on Detroit’s stormwater system. The project aligns with the city’s broader sustainability goals, including the Beltline Greenway initiative, which will pass directly behind the property, integrating the building into Detroit’s expanding network of green spaces and bike paths.
The Belt Line Center serves as a model for revitalizing historic buildings through innovative financing and sustainable design, enhancing Detroit’s environmental resilience. (Ref.1-5)

Fjärdingsparken is a city park that has been constructed in two phases, the second finishing in 2023 [Ref. 1]. The initial phase of the plan focuses on building a new kindergarten, and it includes developing the park surrounding the kindergarten to increase locals' access to green space and recreation. The first phase also involved building a football field at the park's edge [Ref. 1, 4, 5]. The second phase continued the park's development focusing on rain water management and biodiversity. The park was constructed so that up to 900 m3 of rainwater can be managed in the park during a 100-year rain, protecting the surrounding area from flooding. This is part of a flooding strategy for the city. The park includes a meadow, aiming to provide habitat for flowers and plants supporting pollinators and butterflies. It also contains amenities such as an outdoor gym, a dog park, and a "play forest" designed for children. The climate impact of constructing the park was evaluated in an attempt to reduce GHG emissions [Ref. 1-3].

The Joe Louis Greenway is a 27.5-mile recreational pathway designed to create safe, connected, and equitable spaces throughout Detroit. It will link 23 neighborhoods across Detroit, Hamtramck, Highland Park, and Dearborn, connecting them to each other and to the Detroit riverfront. The greenway will transform a blighted, abandoned rail corridor into a park that runs through the heart of Detroit's communities. (Ref. 2, 3)
This project is guided by a Framework Plan funded by the Ralph C. Wilson, Jr. Foundation and shaped by extensive community input. Residents voiced a strong desire for the greenway to provide off-street recreation and increased access to green spaces across Detroit. Additionally, they advocated for the restoration and remediation of former industrial sites, which the Conrail section of the greenway will address. (Ref. 4) The design incorporates stormwater management to mitigate flooding, native meadow plantings to support bird habitats, and tree-lined paths for shade and improved air quality. The Framework Plan ensures the Joe Louis Greenway will transform infrastructure that once divided neighborhoods into one that unites them, reconnects natural systems, drives economic redevelopment, and fosters a resilient social network. (Ref. 13)
The concept originated in 2007 with the Friends of the Inner Circle Greenway local NGO and became part of the Detroit Greenways Coalition Network Vision in 2009. The Detroit Greenways Coalition Network Vision is a comprehensive plan developed by the Detroit Greenways Coalition (NGO), an organization dedicated to promoting non-motorized transportation and green infrastructure throughout the city. After years of advocacy and collaboration with the city of Detroit, the project’s route was finalized. In 2017, Mayor Mike Duggan announced the greenway would be renamed in honor of Joe Louis, the legendary boxer and Detroit native who championed African Americans' rights and symbolized social justice. (Ref. 1, 2,)

Cagliari's waterfront is currently characterized by extensive soil sealing, which has rendered the soil impermeable, leading to a loss of biodiversity and contributing to the urban heat island effect. Additionally, the waterfront is disconnected from the city due to heavy traffic. In 2023, the Municipality of Cagliari launched the "Green Promenade for Cagliari’s Seafront" project, aimed at revitalizing the waterfront and reconnecting the city with its coastal heritage. Led by Stefano Boeri Architetti, the project seeks to transform the area into a continuous green space that integrates pedestrian pathways with shaded public areas, functioning as a "green lung" to mitigate urban heat and enhance biodiversity.
The initiative will introduce over 200 new trees and 5,700 square meters of green space, creating a park that beautifies the area, improves air quality, and lowers local temperatures. A key focus of the project is fostering cultural and social inclusion by developing new community hubs that encourage diverse activities and strengthen social cohesion. Additional features include recreational areas, sports fields, and outdoor seating. (Ref. 1, 2,3)
The project also aims to enhance social inclusion, environmental sustainability, and urban connectivity, ultimately transforming the waterfront into a vibrant public space that reflects Cagliari’s identity.
However, the lengthy construction process has disrupted local businesses and reduced foot traffic, making the area less attractive during the redevelopment phase. (Refs. 10, 11, 12 & 13).

The Floating University was initiated in 2018 at the rainwater retention basin of the former Tempelhof airport in Berlin. Though not an official university, it serves as a space for transdisciplinary, communal learning, transforming an abandoned urban site into a vibrant community resource. The project reclaims the basin, hosting workshops and events that range from ecological lectures to cultural and art programs, fostering collaboration between diverse disciplines and communities.
The architecture collective raumlaborberlin originally envisioned the project as a six-month initiative. Artists, universities, and seminar groups contributed to designing the space and organizing workshops. However, due to its success, an NGO, Floating e.V., was established to sustain the project. Today, the NGO manages the site and continues its mission of engaging communities with urban and ecological themes.
After Tempelhof airport closed in 2008, the basin was infrequently cleaned, leading to contamination and sediment accumulation. Over time, a wetland ecosystem emerged, attracting plants, insects, birds, mammals, and amphibians. This natural development complements the Floating University’s infrastructure, which consists of open timber structures like a kitchen, art installations, communal spaces, vertical gardens, gardening beds, and an auditorium. These structures integrate seamlessly with the basin’s existing technical framework and wetland environment.
Floating e.V. aims to make the basin accessible to Berlin’s urban population while sparking discussions about urban climate, resource management, and water cycles through diverse and artistic programs. Smaller initiatives focus on specific ecological themes, such as plant diversity and soil health, through projects like a seed archive and soil lab.
The Floating University exemplifies how abandoned urban spaces can be revitalized into hubs for learning, creativity, and ecological awareness. (1-3, 8, 9)