Urban offsetting model (biodiversity or water)

The Ringsend Open-Air Laboratory project in Dublin, Ireland, is part of a broader effort to adapt urban areas to increasing climate change risks. This initiative focuses on installing green roofs and deploying a network of environmental sensors to enhance urban resilience. Launched in 2018 under the Horizon 2020 OPERANDUM project, the effort seeks to find nature-based solutions for climate change impacts worldwide. Led by the University of Bologna, OPERANDUM involves over 20 partners, primarily in Europe, working together to address environmental challenges like flooding, drought, and coastal erosion through the establishment of ten "Open Air Laboratories" globally.
In Dublin, the project aims to bolster flood resilience in Ringsend, a critical economic area near the city’s tech district, which faces substantial flood risks due to its low elevation and proximity to the Dodder River. This river, which flows through both rural and urban areas before meeting the River Liffey near Ringsend, has caused property and infrastructure damage from extreme rainfall and combined river and tidal flooding.
Green roofs play a key role in mitigating urban flood risks in this project. These rooftop gardens absorb large volumes of rainfall before it reaches the streets, easing the load on existing flood prevention systems like storm drains and gullies and reducing the need for additional "grey" infrastructure. Based on community insights and recommendations, construction has begun on a green roof on top of the CHQ building in Dublin’s Docklands, in partnership with Dogpatch Labs.Complementing this, over 100 sensors have been deployed in recent research trials across Dublin. OPERANDUM researchers are now building on this foundation to create a denser, more reliable, and cost-effective sensor network, with data from earlier low-cost sensor trials made publicly accessible via Dublinked, Dublin’s open data platform, and exploring the use of LPWAN for environmental sensing. (1-5, 7)

The "Mangle Verde" project is a community-led intervention aimed at reforesting mangrove areas in Cartagena, particularly around the Ciénaga de la Virgen and Ciénaga de Juan Polo. Initiated by Gloria Sánchez and other members of the Villa Gloria community, this project is a response to the environmental degradation caused by urban development, including the construction of a viaduct, and the damages inflicted by invasive settlements and pollution​(ref 1,4). The primary goal of the project is to restore the mangrove ecosystems, which are essential for maintaining water quality, preventing coastal erosion and supporting marine biodiversity conservation (ref 4). In addition, this initiative provides socio-economic benefits by fostering ecotourism and increasing fish populations, which directly benefit the local fishing economy​(ref 1). The "Mangle Verde" project emerged as a grassroots response to compensations granted by the Concesión Costera for the damage caused by infrastructure projects in the region. Local residents of Villa Gloria, recognizing the importance of the mangrove ecosystem, established nurseries in their homes where they cultivate three types of mangroves (ref 2,4). So far, the initiative has planted over 26,860 mangrove saplings and is committed to continuing the reforestation efforts, which also include cleaning and maintaining the canals around the mangroves​ (ref 1). Beyond ecological restoration, the project also addresses key environmental risks in Cartagena, including coastal flooding and habitat degradation, driven by both natural phenomena (e.g., tides) and human activities such as urban sprawl and illegal dumping (ref 6, 7).

The riparian forest of Montgérald, through which the “Monsieur” River flows, is located within Fort-de-France and boasts rich biodiversity, featuring around 100 species of shrubs and trees and about 30 animal species, including 16 types of birds. It is one of the last remnants of the mesophilic forest type and the only example in a French peri-urban setting. This unique ecosystem is recognized as a Natural Area of Ecological, Faunal, and Floral Interest (ZNIEFF) and a Classified Wooded Area (EBC), underscoring the need for conservation efforts.
Covering nearly 21 hectares, this site offers ecological benefits like air quality improvement and temperature regulation, providing a "fresh air island" near the city center. However, it faces significant challenges, including flooding caused by climate change and heavy rains, which exacerbate erosion along the Monsieur River. The area is also threatened by invasive alien species, making conservation measures even more crucial.
Since 2015, the municipality of Fort-de-France, along with project partners, has been working on developing this natural space for both conservation and public engagement purposes. The most recent actions occurred in 2020, including riverbank restoration, clearing invasive species, and creating walking paths and educational installations. Additionally, the project features an awareness campaign targeting local schools. The ongoing initiative aims to merge biodiversity conservation with community recreational use and environmental education, ensuring the resilience of this vital ecosystem against the impacts of climate change. (Refs. 1, 2, 3)

Chandler Park, a historic park in Detroit constructed in the 1800s, underwent multiple expansions from 1922 to 1950 to include amenities such as a pool (later converted into a water park), a golf course, and public green spaces. In 2013, an expert panel recommended constructing a 2.5-million-gallon marshland within the park to provide a unique recreational and educational feature and incorporate green infrastructure principles for improved stormwater management. Completed in December 2019, the Chandler Park marshland was a collaborative project between The Greening of Detroit and the Chandler Park Conservancy, designed to enhance Green Stormwater Infrastructure (GSI) across 200 acres.
The marshland manages 2.5 million gallons of stormwater, substantially reducing the load on Detroit’s combined sewer system and minimizing basement flooding during heavy rains. Engineered with rain gardens, bioswales, and a pump system circulating up to 4 feet of water, the marshland fosters a balanced ecosystem with higher oxygen levels, benefiting local flora and fauna.
With 4,500 native plants, the marshland supports diverse wildlife, including migrating birds, turtles, frogs, pollinators like bees and butterflies, and natural mosquito predators. This project not only contributes to flood mitigation but also improves water quality by capturing stormwater and allowing pollutants to settle.
Additionally, the marshland provides a foundation for future environmental education, with plans to add an outdoor classroom and public learning spaces. The use of native plants ensures low maintenance and sustainability, requiring minimal water and fertilizers. By creating new habitats and recreational areas, the Chandler Park Marshland promotes biodiversity, environmental education, and community engagement, while alleviating urban runoff’s impact on Detroit’s sewer system.
(Ref.1-3)

The Panke is a watercourse that rises outside Berlin and reaches the urban area of the city, flows through the districts of Pankow and Mitte and flows into the Berlin-Spandau Ship Canal in Wedding. The length of the Panke is around 29 kilometres. Almost the entire length of the Panke in Berlin (around 17.6 km) is to be renaturalised - on the section from the state border in the north of Berlin to its confluence with the Berlin-Spandauer-Schifffahrtskanal (BSSK). The Panke is currently a small watercourse that has been heavily remodelled by humans. In large parts of the watercourse, the banks have been straightened like a canal and reinforced with sheet piling, among other things. Existing riverbed drops and weirs prevent fish from travelling unhindered through the watercourse. Studies on water body (structural) quality, typification and other biological quality characteristics have shown that the Panke has poor status values in the majority of Berlin's sections, e.g. in terms of the fish population. The negative assessment results are primarily attributed to the lack of habitat and structural diversity, the lack of passability of the watercourse and, in some cases, high nutrient loads. (Ref. 1)

The restoration of the river was initiated by the State Berlin, following the European Water Framework Directive. The central aim is to implement flood plains and recreate the pre-straightened water course, to ensure space for flooding, habitats for more diverse flora and fauna, increase water flow for better water quality and create a site for recreation in a densely built city. (Ref. 1; Ref. 2) The project started back in 2003 and is expected to be finished in the 2030s (Ref. 2; Ref. 7).

The Establecimiento Público Ambiental (EPA) Cartagena has led multiple tree-planting initiatives in the Mamonal Sector as part of its ongoing efforts to promote environmental sustainability in Cartagena. The main goals of this initiative are to recover and enhance urban green spaces by planting trees, improve air quality and build a strong environmental culture within the community. In April 2024, EPA Cartagena led a tree-planting and public space recovery initiative in Nuevo Oriente, in collaboration with local authorities, community representatives, and the private sector, such as Veolia, as part of its ongoing efforts to strengthen environmental education and promote urban sustainability (ref 1). In a related tree-planting campaign, 210 new trees in Mamonal and Membrillal to help mitigate climate change, reduce air pollution, and protect local biodiversity. The effort received support from local industries such as Etex and AM SAS Mamonal. This campaign also aimed to enhance the natural environment in industrial areas and to encourage other companies and community members to join in environmental restoration efforts (ref 3).

This initiative was launched by the local government of La Paz, focusing on afforestation of the Mallasa landfill, which was closed in 2004 (1-4 & 6-10). While some plantations were established in the area when the landfill was closed, the overall plan aimed to manage the waste until the site was sufficiently clean for new projects—a process expected to take at least a decade (6). By 2021, signs of biodiversity, including flora and fauna, had begun to return to the former landfill. In response, the municipality of La Paz implemented a project to plant 6,000 native tree species, along with other shrub species, to further enhance biodiversity regeneration and establish a second urban forest in the city (3 & 4 & 7 & 8).

The afforestation efforts took place between 2021 and 2022, coordinated through "forestry brigades" made up of diverse volunteer groups. These groups included members from public institutions, private company representatives, NGOs (both environmental and non-environmental), universities, religious organizations, and local citizen groups (8-10). A total of 12 hectares were reforested out of the 33-hectare area (1 & 7). Following this, the area was closed to the public and is expected to become a biodiversity sanctuary within ten years, with ongoing monitoring by the municipal environmental agency (7). Among the trees planted, some were chosen to attract birds with their fruit, others to support the pollination of hummingbirds and bees, while others were intended to enrich the soil with nutrients—all species being native to the region (3 & 7).

Additional goals of the initiative include raising awareness about climate change, fostering a sense of environmental stewardship through community engagement, and advancing the municipality's decarbonization plans (3 & 9). Some of the seedlings and saplings were purchased by the municipality at a cost of 6,160 euros, with private companies also contributing financial support to the initiative (1 & 7).

In an architecturally important area of Berlin, situated between the Landwehr Canal, the Kulturforum (the Berliner Philharmonie and the Berlin State Library) and the new construction on Potsdamer Platz, a combination of green and grey infrastructure has been realised to minimise the burden on Berlin’s existing water infrastructure.
Green and non-green roofs harvest annual rain, which flows through the site’s buildings and is used for toilet flushing, irrigation, and fire systems. The roofs retain and then release water to the large on-site buffer pond, which has five underground storage tanks. Next to the roofs, a series of urban ponds and connecting canals have been implemented, with a combined area of approximately 1.2 hectares. They are filled with rainwater, creating an oasis for urban life. Vegetated biotopes are integrated into the overland landscape and serve to filter and circulate the water that runs along streets and walkways. The lake’s water quality is excellent, forming a natural habitat for animals and cooling the surroundings, while fresh water usage in the buildings has been reduced. (Ref. 1; Ref. 2; Ref. 3; Ref. 6)
The project was implemented in the 1990s as part of the development of Potsdamer Platz in the wake of the reunification of Germany. Several architects collaborated on the implementation that was completely privately funded. Beyond its ecological and technical features, the site is a blue natural site in the heavily built city centre of Berlin and allows people to linger and enjoy natural features. The drainage system won several sustainability prices and is considered a successful integration of nature and technology-based mechanisms to foster climate change adaptation. As the rainwater system stores rainwater in underground tanks and ponds, the urban sewage system is relieved during heavy rain, and water can evaporate. Therefore, the small water circle is closed, and the microclimate is cooled. (Ref. 2; Ref. 6)

The Recovery of Cienaga Juan Polo project is primarily aimed at reopening the natural mouth of the Manzanillos to restore water flow between the sea and the Juan Polo coastal wetland, which has been affected by human activities leading to high salinity and water stagnation issues (ref 2). The project is led by Fundacion Serena del Mar. Environmental and social sustainability are core components of the project design, which has included extensive community consultations since 2013. These consultations have resulted in agreements covering employment opportunities, education, and infrastructure development (ref 2). Key implementation activities include the reforestation of mangroves and targeted interventions to address ecological degradation, such as increased salinity, water stagnation, and biodiversity loss (ref 2). The project also seeks to enhance the quality of life for surrounding communities by restoring traditional economic activities, particularly fishing, and integrating sustainable urban planning elements such as canals, sluices, and navigable waterways. These features are designed to support the development of a "blue corridor" for aquatic mobility within Serena del Mar (ref 2, 3). In addition, it also contributes to local capacity building through environmental education programs that engage community members, researchers, and NGOs in biodiversity monitoring and sustainable practices​ (ref 1).

The "EnRútate por el Ambiente" initiative is a collaborative strategy implemented in Cartagena through a partnership between Ecopetrol, EPA Cartagena, and the Cartagena Refinery. The initiative aims to promote sustainable community development in neighborhoods adjacent to the refinery by addressing key environmental challenges such as pollution and the degradation of water bodies and green spaces. Its overarching objective is to improve quality of life through the promotion of sustainable practices and environmental stewardship (ref 5).
The strategy is structured around three programs. The first component focuses on the management of public spaces for recreation and environmental care. The second, Guardians of the Channels, seeks to empower local residents as promoters of water body conservation within their communities. The third program promotes the engagement of all community members, including schools and educational institutions, through participatory environmental initiatives (ref 1).