Green densification model

After its abandonment by the British military in 2012, the development of a new utilization concept and plan for the former military base in Gremmendorf was encouraged by the city’s planning department. Intensive citizen participation efforts were identified and ideas conceptualized, followed by an architectural competition based on which the spatial development plan was elaborated. The plan, which is currently being developed further by the winning architecture bureaus in coordination with the spatial development authority, intends the development of an attractive living quarter as a "garden town" with several green and sustainable drainage elements (Ref. 1 and 5).

B.Bylon Roof Park is a green park on top of the B.Amsterdam building which provides a healthy environment for employees and citizens of the neighbourhood. The park contains a vegetable garden, recreational facilities, meeting spots, sport facilities, a herb garden, a water basin, fruit trees, chickens and a restaurant (1,2,5,8). The roof park stores and uses storm water and an organic circular decomposing system provides plant nutrients. (4,7).

In 2008, a green wall of more than 500 m^2 using a hydroponic watering system was developed on the side of the Max Juvenal bridge. Designed by Patrick Blanc, french botanist and pioneer in the development of green walls, it is considered an "authentic work of art, which evolves over time and the seasons and contributes to "renaturing" the urban space" (Ref. 4, page 7). The wall is intended to illustrate the benefits that green walls can bring to the environment, such as the reduction of heat islands in urban areas and their contribution to cleaner air due to the production of oxygen and the reduction of CO2 rate by photosynthesis (Ref. 1).

Wakefield Council is "responsible for managing over 2650 acres of grass in parks and countryside areas across the Wakefield district (this includes cutting the grass)". Since 2015, there are small areas where "the grass is being left to grow" naturally for environmental benefits. (Ref. 1) The objective of the project by leaving derelict some grass areas are that "the environmental benefits of leaving some grass to grow naturally include encouraging wild flowers to grow which will support bees and other insects, and aiding drainage to reduce flood risk" (Ref 1).

It is the most extensive green roof in Lublin, designed to cover 16,700 square meters rooftop area of the shopping mall 'Castle Terraces' (Tarasy Zamkowe). Its purpose is to serve as a green recreational area for relaxation and public events, as well as an ecological solution for heat mitigation and water retention. The roof is divided into two parts: 1) an area accessible to the public with flower meadows, walking paths, viewing points from which the visitors can see Lublin’s old town 2) ‘intensive cultivation area’ with endemic trees, bushes and succulents which are not directly accessible to the public [1,2,3,8].

Appletree is an outdoor community resource, where people of all ages and from all walks of life, get together to grow e.g. fruit, and contribute to developing and maintaining the area. The growing space and garden are divided into different areas, offering a range of gardening experience. The community also contributes to their permaculture, wildlife and wildflower areas. The community is constantly planting and regenerating areas of the garden. (Ref. 1)

The Polder Roof is a green roof originally installed on the top of the Old School Amsterdam, Gaasterlandstraat, Amsterdam with innovative controllable water storage and drainage system on which crops are grown, solar panels are installed and that provides space for recreation. (1,2) Thereby, it combines multiple benefits including the reduction of heat stress, noise reduction, sustainable energy provision, biodiversity, food production and climate change adaptation (2,7). The Polder Roof was a pilot project that won an innovation award and is viewed as an example for urban climate change adaptation solutions. (2).

In 2019, due to the renovation of the former Old School building, it was necessary to relocate the Polder roof to a different place. The Polder Roof is a completely de-mountable system, made up of crates with a sedum layer on top, thus it could be removed quite easily from the Old School roof and put somewhere else. In the name of circularity, the sustainable drainage system was moved to the roof of the South Food Bank building. (10,11,12) With the relocation of the Polder Roof system, however, the size of the green roof has decreased to 1200 sqm from 2010 sqm (2).

The project assumes planting roses and other flowery shrubs in the Szczecin's district of Kijewo. Characterized by heavy traffic, the area has benefited from 'rose gardens' along its main roads and neighbourhood squares as a way of mitigating the traffic noise. The rose gardens serve as natural acoustic screens for noise reduction. The initiative additionally aims to enhance the aesthetics of the area and the image of the Szczecin's city - in line with its long-term brand management strategy "Szczecin floating garden 2050". According to the initiators of the project, it refers to the tradition of roses, which would decorate the same neighbourhood in the past [1].

Due to the challenges caused by climate change, Hamburg decided to become greener and developed a comprehensive, pioneering green roof strategy. The strategy aims at creating 100 hectares of new green walls by 2019 by providing grants for building owners for greening roofs and offering them rain water fee reduction owing to the rain water retention of the green roofs. (Reference 1) The financial support offered until the end of 2019 is 3 million EUR. (Reference 2) The services offered by the city in this plan consist of four pillars: promotion (financial incentive), dialogue, regulation, and scientific support. (Reference 7)

Since the mid-eighties, several German cities like Karlsruhe have been implementing green tram tracks, followed by a period of decline due to incompatibility with technical and construction requirements (Ref. 2). Since around 2003, the city of Karlsruhe has re-introduced the greening of tram tracks with the main objectives of noise reduction and cloudburst infiltration (climate adaptation). Mostly in combination with urban redevelopment projects, several tram tracks across Karlsruhe have been renewed and greened in different forms by using continuously advancing technologies (Ref. 3, 6 and 7).