Vacant space model

Zollverein is an abandoned colliery and coking plant near the center of Essen in Germany (Ref. 6). Since 1993 the mining here stopped, and the site was turned into a derelict area, so nature could win back its territory. Most of the railway tracks and the smaller industrial leftovers are now covered with moss, grass, and weeds (Ref. 4). After the site was recognized as a World Heritage Site in 2001, it started being developed as a multifunctional cultural, tourist and recreational center keeping and developing biotopes that emerged over time (Ref. 11).

In 2016, the project facilitated the revitalization and development of green areas in Dąbie (by an urban part of the Vistula River) to create the Dąbie Park. The park had been a neglected vacant green space with randomly scattered former playground facilities. The initiative involved greenery management and creation (bushes, trees, flower meadows), building new sports facilities (running/cycling paths, a basketball field), new infrastructural solutions (new water drainage system, a viewpoint) and creating a safe and modern space for children in a playground surrounded by large trees which provide shadow. The modernization and revitalization of the park infrastructure and local greenery have made the green riverbank area accessible to the public [1,4,5].

A 21-kilometer regional cycle and footpath between the cities of Essen, Mülheim am der Ruhr and Duisburg was developed from the former unused railway route of the Rheinische Bahn. The path was landscaped to ensure the comfort of pedestrians and cyclists. Part of the route passes through Emscher Park and become a full-fledged part of the green infrastructure of Essen (Ref. 1).

When the national German railway company shut down parts of the former East station of Leipzig and its tracks in 2012, citizens developed an idea for its secondary use and came up with the concept of the "Parkbogen Ost" which represents a 5-kilometre long circle of bicycle lanes, footpaths and outdoor space surrounding the East of Leipzig. The city of Leipzig recognized its potential to connect the Eastern Leipzig with the city centre and developed the strategy further by issuing a "Masterplan Parkbogen Ost" as the base for a step-wise implementation of the project in 2013 (Ref. 5).

In 2013, local activists came up with an initiative to plant 100 trees and 100 bushes in different parts of the District XIII in Kraków. It was supposed to be financed by the participatory budget of Kraków. Still, the delay in implementation led to a situation when the second project by the same team (plant 101 trees and 101 bushes) overlapped with the previous one the following year. The city implemented the original idea, and the district received 100 trees and 101 bushes in 2015. The project aimed to increase the aesthetic and decorative value of the area and to increase the comfort of living of its inhabitants, as well to obtain funds for urban greenery management [1,3].

EPAEM (Euromediterranean public development establishment) launched the development a new park of 14 hectares. Located in former industrial area at the gates of the northern districts of Marseille, it is considered to be one of the poorest districts in France (Ref. 1). The planned park Aygalades is divided into two parts: the southern part of 4 hectares called Bougainville Park and the northern part of 10 hectares which runs along the Aygalades river (Ref. 1). Development work on Bougainville Park is set to begin in September 2020 with completion in 2023 (Ref. 12). The park is described as "the first step of a large project to restore a highly degraded industrial site" (Ref. 12).

The ‘University Park Essen’ is developed on a former railway site in the inner city of Essen, that had been a wasteland for almost 30 years. By revitalizing this about the 13-hectare large plot, an urban green quarter for residential and commercial use is created. The centricity of the park within the new quarter between the city center, shopping mall Limbecker Square and the university campus is the first visible component of the development and therefore shapes the new identity of the quarter (Ref. 4).

“The Nottingham in Bloom campaign is a city-wide partnership which includes residents, businesses, schools, community groups and a wide range of volunteers. The aim is to encourage more people to get involved to improve their local area. Together they [through the campaign] produce horticultural excellence and enhance the local landscape, the environment and the character of Nottingham.” (Ref. 1)

A new lake with green banks was built in the district of Altenhof in Essen in order to improve the quality of life in the neighborhood, create new recreational facilities and prolong the existing transport and green infrastructural developments in Essen. The water is supplied to the lake by means of groundwater from a separate well, as well as rainwater from the surfaces of neighboring roofs (Ref. 1).

Arkwright Meadows Community (AMC) Garden is situated in the heart of inner city Nottingham, Prior to 2001, the site was a disused, derelict and rubbish-strewn piece of land. In 2001, a group of Meadows residents came together to improve this derelict piece of land and work started to create the infrastructure of the community garden. The area was transformed into a green oasis and outdoor learning environment. (ref. 8)