Greening the Bunker - A utopia becoming reality?

 

By Phaedon Angelopoulos & Nanne Richardsen

In St. Pauli, a Hamburg neighbourhood with world-famous nightlife, a WW2 bunker is being transformed into an green urban oasis. Five additional floors have been added on top of the bunker in the past years, reaching a final height of 58 metres. Its sheer height makes the multi-level rooftop garden a viewing platform for its visitors and a landmark itself. The visualisation of the Bunker greening, supposed to be finished in October 2023, shows a greened staircase added to the outside of the building, merging and allowing access of the construction with the public park below. Originating from the idea and request of a local citizen initiative and expected to provide various ecosystem services to the neighbourhood, the project seems like a prime example of urban greening. Nonetheless, it faces criticism regarding the beautification of a Nazi Germany landmark built by forced labourers.

Picture 1: Visualisation of the planned project, perspective from ground (Planungsbüro Bunker/Matzen Immobilien) Source: https://www.bunker-stpauli.de/wp-content/uploads/2019/08/Bunker-St.Pauli-Rendering-004.jpeg

In 1942 the flak bunker was built to provide shelter to up to 25000 people during the Second World War, while mainly serving air defence purposes. After the war ended, the bunker in St. Pauli was never demolished since the amount of dynamite to destroy the 3,5 metre thick walls would cause serious damage to surrounding buildings. Instead, it was used as a media centre starting in the 1950s and turned into a cultural space for music and arts, hosting the club and concert venue ‘Uebel & Gefaehrlich’ up until today. The complex is owned by the city of Hamburg but managed by Matzen Immobilien GmbH & Co. KG who is a long-term leaseholder for a time span of 99 years. A local citizen initiative came forward with the idea to green the bunker’s roof and make it accessible to the public. Included in their plan was a space to commemorate the 1000 forced labourers who built the complex in less than 300 days without any protection from air strikes. Contrary to voices claiming that the bunker itself is a reminder of its history, Anita Engels, council speaker of Hilldegarden, stresses that the building lacked a memorial and visitors were unaware of its history, specifically the forced labour. The citizen initiative, which during the process self-organised as the Hilldegarden organisation, will be a non-profit tenant in the bunker project. The contract between the city of Hamburg and the leaseholder Matzen secures so-called ‘Stadtteilflächen’, spaces in the complex reserved for local non-profit initiatives, like Hilldegarden.

The added floors are set to house a hotel, while others will be rented out as business spaces once the project is finished. As the floors are designed in a pyramid shape, the roof greening will be installed on all five new levels, the top roof and a stairway. By doing so, the roof not only gains a new purpose but also loses its former one as an air defence base. Instead of beautifying a relic of the Nazi regime, it is permanently transformed. While its primary function is substantially different, its form continues to serve as a reminder and thus all but erases its past.

The term “Urban Ecosystem Services” refers to the benefits people draw from nature and ecosystems found within urban areas. They are divided into five key categories based on the service they provide towards the quality of the local environment, such as air purification, or rainwater management. Cities, including Hamburg, are characterised by high density in the built environment, leaving little room for Ecosystem Services, particularly those that have to do with air quality, leisure and heating management. Indeed, as we can see in the ‘before’ photos of the site, it is bordered by a park with several more in its immediate vicinity, yet the site itself is entirely built of concrete. This lack of Urban Ecosystem Services on the site is what some of the stakeholders involved with the project are aiming to rectify.

Picture 2: “Before”, historical Imagery from 2000, showing the bunker and undeveloped, or in the process of being developed, surrounding area. Source: Google Earth

The bunker project aims to transform the existing structure into an oasis of green space, and by extension provide a range of ecosystem services within the dense urban core of the city. This case study falls under the “urban forest” category, with approximately 5000 plants and 7600sqm of green space planned. Additionally, this ecosystem service has the capacity to provide cleaner air in the surrounding areas, target the heat island effect by creating a microclimate, thanks to the volume of vegetation. Further, Nature-based Solutions have been shown to effectively address biodiversity challenges in urban areas. In this case, we are talking about a novel ecosystem, which can only improve the local microclimate by reducing the area of bare concrete.

Picture 3: “Now”, current Imagery showing development. The bunker can be seen at the top of the image surrounded by cranes. The empty space shown in the previous image is used as an event space and is publicly accessible. Source: Google Earth

The planned development, funded by private investment, incorporates Environmental Services. Whether the expectations regarding the ecosystem services will be met, will be assessed by a team of researchers from the TU Berlin. To measure ESS like temperature regulation, air humidity, wind speed and evaporation, the team installed 80 sensors, which will provide data over a timespan of five years from the inauguration of the construction.

Picture 4: “After”, visualisation of the planned project with height expansion and greening. Source: Planungsbüro Bunker/Matzen Immobilien https://www.bunker-stpauli.de/wp-content/uploads/2019/08/Bunker-St.Pauli-Rendering-001.jpeg

The completed project is supposed to include a wide range of Ecosystem Services, namely belonging in the categories of air purification, climate regulation, biodiversity and habitat as well as aesthetic and leisure. The site is subject to various goals, ranging from ecosystem service provision to the environment and the neighbourhood over economic success for the leaseholder to the creation of a memorial by Hilldegarden. Whether the multi-purpose construction will be successful depends on the perspective, as Engels stresses. But even though only the future will reveal if expectations are met, the initiating role of citizens in the planning process is a prime example of how greening in the city can be implemented in co-creation.

 

References:

Bolund, P. and Hunhammar, S. (1999) “Ecosystem services in urban areas,” Ecological Economics, 29(2), pp. 293–301. Available at: https://doi.org/10.1016/s0921-8009(99)00013-0.

Bunker St.Pauli (n.D.), "Der Bunker St. Pauli", www.bunker-stpauli.de.

Engels, A. (2023) "Hilldegarden and the St. Pauli bunker development". Interview by Nanne Richardsen [phone], 28 April.

Hilldegarden e.V. (N.D.), "Hilldegarden", www.hilldegarden.org.

Schröder, A. (2019), "Kann man aus einem Nazi-Bunker ein Hotel machen?", Deutschlandfunk Kultur https://www.deutschlandfunkkultur.de/streit-um-flakbunker-auf-st-pauli-kann-man-aus-einem-nazi-100.html.