Urban offsetting model (biodiversity or water)

At the beginning of the twenty-first century, Kunming’s urban planning faced major challenges, including fragmented development, environmental degradation, and limited green spaces (Ref 1). In response, the municipal government launched a series of strategic plans aimed at promoting high-quality urban development and environmental restoration.
Baisha Lake was identified as a key area in these strategies, with plans for Baisha Lake Park first highlighted in 2017 (Ref 2) and reaffirmed in the "Opinions on Supporting High-Quality Development in Kunming" in 2021 (Ref 2). To implement parts of this broader strategy, the government entered into public-private partnerships. In 2018, land development rights for parts of East Baisha Lake were granted to Dahua Group, on the condition that 40% of the area be reserved as green space and that ecological restoration efforts be undertaken (Ref 3, 4).
The Eastside Baisha Lake Park project, launched by Dahua Group in February 2023 (Ref 3, 5), is thus one component of this larger government-led urban renewal effort. The project follows the city's planning framework of “one lake, six zones, 46 scenic nodes” and includes 55 hectares of green space, with 40% designated as parkland. By the end of 2023, 6.5 hectares had been completed, and the south bank of the park opened to the public in September 2023 (Ref 3, 6).
The broader East Baisha Lake area's development was originally planned by the state-owned Kunming Urban Construction Company, but land rights were later transferred to Dahua Group. Thus, while a private developer is leading the construction, the project remains a part of Kunming’s publicly driven strategy to restore the lake and enhance urban livability.

The Upper Detroit Riverfront Habitat and Parks Restoration Project aims to restore and enhance vital fish and wildlife habitats along the Detroit River. This initiative seeks to rehabilitate approximately 30 acres of upland and shoreline habitats within Riverfront-Lakewood East Park, A.B. Ford Park, and Mariners Park (all located alongside the river), covering nearly one mile of the Detroit River and its shorelines.
Key outcomes include improving approximately 1,000 linear feet of existing shoreline along the Detroit River by incorporating native wetland edges and fish spawning shelves into the restoration efforts. The project also plans to enhance around 2,000 linear feet of canal shoreline and 800 linear feet along Fox Creek to create or improve habitats for fish and herpetological species. In Riverfront-Lakewood East Park, 28 acres are targeted for the establishment or enhancement of native vegetation to support birds, mammals, and pollinators. If feasible, the creation of about 7 acres of wetlands, along with shallow and deep-water habitats, is also part of the vision.
The project is guided by the City of Detroit's 2017 Parks and Recreation Improvement Plan and represents part of a broader strategy to revitalize the city’s green spaces after years of underfunding. With renewed commitment, the city has allocated nearly $12 million to enhance neighborhood parks, particularly in areas that have lacked investment over the past decade.
However, the project was temporarily halted in 2020 due to high water levels causing flooding in the adjacent neighborhood. As of 2024, it remains on hold while the City of Detroit conducts a flood mitigation study. Despite this delay, the project remains a critical step toward fostering community stewardship and creating sustainable green spaces that improve the quality of life for all Detroit residents.
(Ref. 1, 4, 5)

A new addition has enriched Gdańsk's green spaces: the park at Szubieniczna Mountain near the Gdańsk University of Technology. This area, located behind the cutting-edge STOS building housing the "Kraken" supercomputer, has been transformed into a vibrant urban oasis. Covering approximately 7,500 square meters and costing 3.5 million zlotys, the park introduces a sustainable and welcoming environment for students, residents, and visitors alike.
The park aligns with the university's PG Climate Plan, a strategic initiative promoting environmental sustainability through research, education, and green infrastructure. Historically a neglected area with overgrown trees and bushes, it has now been revitalized to create a functional and aesthetic space that merges ecological values with public utility.
Key features of the park include over 1,500 new plantings—trees, shrubs, and flowers—that enhance biodiversity and create a visually appealing landscape. Ecological innovations such as a rain garden and energy-efficient lighting reflect the park's commitment to sustainability. Recreational and educational facilities include a mini amphitheater, an outdoor gym, and walking paths interspersed with gravel squares surrounded by flower meadows.
A new pathway connects the campus to Szubieniczna Hill, granting access to Gdańsk's largest water reservoir and offering stunning panoramic views. This transformation underscores how urban green spaces can address climate challenges while improving quality of life for the community. The Szubieniczna Mountain Park is not just a park—it’s a symbol of progress toward a greener future for Gdańsk. (1-2)

The Lower Salt River Restoration Project (LSRRP) is a riparian restoration initiative located along the Lower Salt River within the Mesa Ranger District of the Tonto National Forest. This collaborative project seeks to restore a section of the Lower Salt River Recreation Area that was severely impacted by the 2017 Cactus Fire. The Cactus Fire was a significant wildfire that caused extensive damage to vegetation and habitat in the area, highlighting the need for targeted restoration efforts to rebuild the ecosystem and mitigate future fire risks.
The LSRRP’s primary activities focus on removing invasive tamarisk trees, which are highly flammable and contribute to the intensity of wildfires, and planting native seedlings to reestablish local flora. By removing tamarisk trees, the project aims to create a landscape that is more resistant to fire, reducing the wildfire risk for the region. Additionally, the project supports the abundance and diversity of native plant species by removing invasive plants and planting thousands of native riparian tree species.
The restoration efforts also aim to enhance the riparian habitat by expanding two critical vegetation communities—the mesquite bosque and the cottonwood-willow gallery forest. These communities support rich biodiversity and offer essential habitats for local wildlife.
Beyond ecological restoration, the project emphasizes community involvement and awareness. It provides opportunities for the local community to participate in the project through environmental education events for K-12 students and ongoing volunteer involvement in monitoring and maintaining restored areas.
Overall, the Lower Salt River Restoration Project is a proactive effort to protect and revitalize the Lower Salt River Recreation Area, enhancing its ecological resilience and engaging the community in long-term conservation. (2-4, 6, 8, 11)

The Green Corridor Südpanke is a transformative restoration project that unveiled 700 meters of the river Südpanke, connecting Invalidenpark and Südpankepark in the heart of Berlin. This initiative, part of Berlin's broader mission to restore the Panke River, was spearheaded by the state of Berlin with a focus on ecological restoration, biodiversity enhancement, microclimate cooling, and creating recreational spaces to improve the quality of life for residents (Ref. 2; Ref. 3).
Historically, the river in this area was channeled underground. The project brought the Südpanke back to the surface, integrating ecological principles and landscape planning into the design. The restored section of the river now flows openly in a natural watercourse bed, making it accessible to the public (Ref. 5). The restoration was completed in 2021, transforming the area with features such as playgrounds, lawns, benches, and a continuous biking and walking path that weaves through the green spaces.
Work on the project began in 2010 but was interrupted by the construction of the neighboring headquarters of the Federal Intelligence Service. As a result, parts of the green corridor were opened to the public in 2012, with the full restoration completed nearly a decade later, in 2021 (Ref. 3; Ref. 6).
The project established a seamless connection for cyclists and pedestrians from Invalidenpark in the south to Südpankepark in the north. The new open water section cools the microclimate in Berlin's densely built-up center while providing a critical habitat for plants and animals. Embankments and meadows near the Federal Intelligence Service's property support wild bees and other pollinators, fostering biodiversity. The Green Corridor Südpanke is a vibrant example of how urban ecological restoration can contribute to sustainability, quality of life, and resilience in a growing city. (Ref. 2)

The Rain Garden 2.0 project at Gdańsk University of Technology is an innovative green infrastructure initiative that manages and purifies rainwater while enhancing biodiversity. Part of the international NICE (Nature-based solutions for urban climate adaptation) initiative, this project serves as a living hub for testing solutions to address urban climate challenges. Opened in July 2023, the rain garden exemplifies a multifunctional approach to water retention, pollutant filtration, and urban biodiversity support. It is located behind the Faculty of Chemistry's Building C and has a capacity exceeding 11 cubic meters. (Ref. 1; Ref. 6)
The garden, designed by researchers from the Faculty of Civil and Environmental Engineering under the leadership of Prof. Magdalena Gajewska, captures rainwater runoff to prevent urban flooding and mitigate the strain on storm sewer systems. It absorbs pollutants, improves water quality, and supports over 1,100 hydrophyte plants, creating a natural solution for heavy rainfall events.
Beyond water management, the garden contributes significantly to urban biodiversity. Its moist soil and diverse plant species—designed to thrive in a range of conditions—help create habitats for insects and other small wildlife, boosting ecological resilience. (Ref. 1)
The rain garden’s innovative design consists of several key components. The first stage channels rainwater into reservoirs, reducing the energy of inflowing water. Subsequent parts purify the water through sedimentation processes, effectively filtering out pollutants such as those from streets and roads. Early research shows that these purification methods work exceptionally well, retaining a broad spectrum of pollutants before the water reaches the garden’s main basin. The project also benefits from cutting-edge laboratory equipment, allowing for detailed monitoring and analysis of water quality. (Ref. 1)

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)

Bound by miles of steel, concrete, or brick walls, Berlin’s rivers and artificial canals often look alike. Plastic bottles, along with ducks, swans, and perhaps the occasional coot seeking scraps from humans, are some of the few visible signs of life. Underwater, the scene is similarly sparse and monotonous, with only a handful of resilient species able to endure the harsh conditions.
In response to this lack of biodiversity, researchers from the Leibniz Institute for Freshwater Ecology and Inland Fisheries in Berlin collaborated with the engineering firm Wite to create the Vertical Wetland project. This initiative introduced plant boxes that attach to sheet piling along canal walls, extending into the water to form miniature habitats. These boxes serve as refuges for insects, birds, fish, and other small animals, offering hiding spots and sheltered spaces for egg-laying among the roots and boxes protruding into the water. Known as "ecological stepping stones," vertical wetlands enable animals to rest and safely traverse urban waterways, fostering biodiversity along urban riverbanks.
Vertical wetlands present a quick and cost-effective way to ecologically upgrade sections of urban waterways. Although they can’t fully replace natural riverside habitats, these mini-habitats offer substantial ecological benefits. Native river floodplain plants, including willows, reeds, rushes, and shallow-water species like irises and marsh marigolds, provide the foundation of these structures. All materials used are environmentally friendly and biodegradable.
By covering the grey, industrial surfaces of riversides, the vegetation cools the local environment, both on land and in the water, and helps improve water quality. Plant shading cools water, reducing eutrophication risks and creating a healthier habitat for aquatic life.
The Vertical Wetland project’s pilot installation was successfully implemented and tested in 2023 in the Berlin-Spandau Ship Canal. (1, 3, 6)

Sourced from Northern Worcestershire, the River Stour has played a significant role in the industrial heritage of Birmingham and the Black Country (Ref 1). It consists of 11 Water Framework Directive water bodies and multiple tributaries, spanning 200 km in length (Ref 2, 3). Once a pristine Salmonid river that powered the Industrial Revolution, rapid industrialization severely impacted the river, leaving it heavily polluted with sewage (ibid.).
Initiated by the Birmingham and Black Country Wildlife Trust (BBCWT) in 2021, the Love Your River Stour (LYRS) project focuses on Dudley and Wolverhampton, aiming to transform the River Stour and its surrounding green spaces into a beautiful, wildlife-rich source of pride for local communities and to create a corridor for wildlife to thrive through the heart of the Black Country (Ref 4).
Phase 1 of the project was completed in June 2023, bringing significant improvements along the river (Ref 5, 6, 7, 8). In Phase 2, the project will extend to a stretch running through Cradley Heath and Lye (Ref 7, 8). This initiative is funded by the UK Government's Green Recovery Challenge Fund.

The Dublin Urban Rivers LIFE (DURL) project incorporates two interconnected wetlands in Griffeen Park as part of its broader initiative to improve water quality, natural water management and aquatic biodiversity in urban areas. These wetlands were specifically designed as a natural sewage system to treat wastewater from the surrounding areas, addressing a significant environmental issue known as "domestic misconnection." Domestic misconnection occurs when household appliances, such as washing machines, dishwashers, and kitchen sinks, are incorrectly linked to surface water drains rather than the sewage system. This leads to untreated wastewater being directly discharged into local waterways, contributing to contamination.
In the River Griffeen catchment, which includes approximately 12,000 dwellings and associated infrastructure, domestic misconnections are a considerable threat to water quality. The DURL project focuses on identifying and rectifying these misconnected appliances to ensure that wastewater is properly treated before entering the river. This process will not only improve water quality but will also provide flood alleviation and support healthier aquatic ecosystems in the area.
The project is aligned with broader environmental policies, including the River Basin Management Plan 2022-2027, the Water Framework Directive, the Climate Change Action Plan, the Floods Directive, and the draft Biodiversity Plan. One of the key strategies is to use a Geographic Information System (GIS) to streamline inspections for domestic misconnections, making the process faster and more cost-effective.
The constructed wetlands in Griffeen Park, with a standing water depth of approximately 30 cm, are planted with a variety of native Irish species. These wetlands offer a natural, sustainable solution to wastewater treatment, with the potential for similar applications across Europe. (Ref. 2, 4)