Urban offsetting model (biodiversity or water)

Meadow orchards with fruit trees were an integral part of subsistence farming and form part of the cultural heritage of Wuppertal. To preserve and further develop these meadows as an important habitat for flora and fauna and promote their potential for sustainable consumption, 4 such meadows were sponsored, maintained and promoted by the city of Wuppertal in close collaboration with the working group for fruit meadows via events, communal harvesting activities and hands-on courses since 1999. Since 2015, these meadows have increasingly drawn the attention of "foodsharing" movements and during the nationwide research year "future town". (Ref. 1, 2, 6, 8). Enclosed between areas of intensive conventional agriculture and the federal motorway, the orchards as islands of biological diversity are important places of retreat and relaxation. (Ref. 5) Communal activities are also offered, such as the co-creation of “edible experience spaces”, joint harvesting and providing a base for additional social projects (Ref. 6).

Situated on an area of 52 acres, Father Collins Park incorporates many sustainability-focused features and has won a number of awards. Over 1200 trees and 2000 native saplings were planted to help integrate the existing woodland, maximise biodiversity, and vastly increase the ecological value of the park. Also, wetland areas were created to filter and clean the water in the park as part of a recycling system that replenishes and helps clean the lake and water features. The wetland areas mimic the characteristics of natural wetlands and create a special ecosystem that encourages greater biodiversity in the park. (Ref. 1)

As part of the EU Life+ CITYWATER project (of 3 cities), a sustainable stormwater management solution based on biofiltration was implemented in Maunulanpuisto Park in Helsinki, in order to purify rainwater and meltwater and improve water quality in the Haaganpuro Brook.
As the drainage area is heavily trafficked and paved with asphalt, high solid, nutrient and oil levels have occasionally been measured in the rainwater and meltwater entering the Haaganpuro brook. Such contamination is harmful to the fish stocks (e.g. trout) and other organisms in the brook. The biofiltration solution was the first of its kind in Helsinki. The solution also supported the City of Helsinki stormwater strategy, which aims at changing management towards sustainable solutions and states that stormwater should in first hand be infiltrated on spot, where it is created (ref. 1).

After relevant local regulations had been adapted and allowed for keeping apiaries in the city of Białystok, in 2016, the Institute of Biology at the University of Bialystok put six beehives on its rooftop. The initiative aims at increasing biodiversity and pollination in the city. It promotes beekeeping and sustainable production and consumption patterns, and the honey is a brand product of the University [1,3,4].

The company running the Zabalgarbi waste disposal site manages a solid waste–to-energy plant and also houses a mechanical biological treatment (MBT) plant, a composting plant, a landfill and a leachate treatment plant. During construction of the first plant, Zabalgarbi regenerated and recovered the entire Artigas-Arraiz area covering 108 hectares. The area was degraded by shaft mining activity and an opencast quarry. The project aimed at the reforestation and landslide mitigation of this degraded area. Today the area has been reforested, trails were built and space provided for people to enjoy themselves in gardens, picnic areas and along forest tracks. (Ref 1)

Lodge Hill is a nature area allocated to become a settlement capable of delivering approximately 5000 dwellings by 2028 (original plans). Green infrastructure is a key component of the current plans and specific GI implementation will be based on the existing GI assets. Specifically, the plans include green corridors, sustainable urban drainage systems (SUDs), various parks and street greenery, community allotments, buffer zones around sites of special scientific importance (SSSIs) and woodland (Ref 1).
The plans for Lodge Hill have been controversial, as Chattenden Woods and Lodge Hill Site of Special Scientific Interest (SSSI) is a nationally important area of ancient woodland and rare grassland that supports one of the largest populations of nightingales in the UK (Ref. 7, 8, 9).
In 2018 Kent Wildlife Trust started a campaign (#SaveLodgeHill) to ask Medway Council to not to allocate Lodge Hill development, which has resulted in a scaled-back version of the original plans for Lodge Hill from the construction of 2,000 to 500 houses, avoiding any direct loss of the Site of Special Scientific Interest - which will still have an impact on the nightingale's population (Reg. 7).

Wetlands provide a varying degree of treatment of discharged water and are ideally suited for the containment and treatment of polluted water runoff, being a holistic example of Sustainable Drainage Systems (SuDS). The Dublin Local Authority installed an Integrated Constructed Wetland to treat polluted water discharged from the urban area, with the aim of cleaning urban runoff and drainage water. It was meant to purify water that discharges into a pond, and later on into the Tolka river. The project has been very successful in treating polluted water effectively, according to studies. (Ref. 1; Ref. 3)

The project aims to completely redevelop ‘Rozemaai’, a neighborhood in Antwerp, focusing on climate change adaptation, green spaces, and recreation. This includes a sustainable drainage system in which storm water flows via swales into a water stream with nature-friendly river banks, trees and bushes in the neighborhood, green parking lots, allotments and recreational facilities such as picnic tables (Ref. 1, 2, 3, 4, 5). Since 2019, the district has had a new, accessible park in which the Donkse brook plays a leading role (Ref. 7).

From 1850 to 1956 the area Eskesberg was a limestone mine, after that up until 1972 it served as a landfill. When taken over by the city of Wuppertal, groundwater contamination and outgassing required a large remediation to remove toxic substances and recover the area according to nature conservation guidelines. (Ref. 8) Since 2005, it has been turned into a nature conservation area covering 8.5 ha where several rare plants and animals have resettled and thus the area also serves as an important recreational space for residents (Ref. 1, 2, and 3). The project was initiated by the local government, who also collaborate with different partners for maintaining the nature conservation area, such as the biological station, which organizes excursions, performs monitoring on the terrain and sets up bee hives. Also, residents apart from visiting the area can actively participate in its maintenance as volunteers, guided by the city of Wuppertal and the NGO Biologische Station Mittlere Wupper. Furthermore, the nature conservation association of Wuppertal and scientists from the university of Cologne are involved in the intervention by conducting research on the terrain (Ref. 1, 2, 3 and 6).

On 'De Roma', an old cinema that has been renovated into a theatre, a green roof of 650m2 was created which improves biodiversity and contributes to Antwerp's climate change adaptation (Ref. 1, 4). A bee house was also later installed on the roof (Ref. 2). The green roof is created by volunteers of De Roma and Kopspel, which is an organization that provides learning-working places for student of 'Deeltijds beroepssecundair onderwijs (Part-time Secondary Professional Education) and temporary employment for people that want to turn back to the labour market (Ref. 1).