Picnic above the Autobahn // A park above the Autobahn reconnecting a once divided neighbourhood
Edouard Manet's painting "Le déjeuner sur l'herbe" served as inspiration for the new Dorothea Buck Park on the A7 tunnel in Hamburg-Schnelsen. Where once avalanches of cars pushed along in the open air, today - above the traffic noise and a four-lane road - a vegetative biodiversity thrives, residents meet for picnics, neighbourhood children play football in safety, allotment gardeners grow fruit and vegetables on a 3.0 ha green roof.
Local
Germany
City of Hamburg represented by the Eimsbüttel District Office
Mainly urban
It refers to a physical transformation of the built environment (hard investment)
No
No
Yes
2022-09-25
As a representative of an organisation
Name of the organisation(s): POLA Landschaftsarchitekten GmbH Type of organisation: For-profit company First name of representative: Jörg Last name of representative: Michel Gender: Male Nationality: Germany Function: Founder and principal Address (country of permanent residence for individuals or address of the organisation)<br/>Street and number: Neue Schönhauser Straße 16 Town: Berlin Postal code: 10178 Country: Germany Direct Tel:+49 30 240009910 E-mail:mail@pola-berlin.de Website:https://www.pola-berlin.de/en
Edouard Manet's painting "Le déjeuner sur l'herbe" served as inspiration for the new park on the A7 tunnel in Hamburg-Schnelsen. Where once avalanches of cars pushed along in the open air, today - above traffic noise and a four-lane motorway - a vegetative biodiversity thrives, residents meet for picnics, neighbourhood children play football safely, allotment gardeners grow fruit and vegetables. A 3.0 ha green roof on the so-called Schnelsen lid made Manet's picturesque illusion of breakfast in the countryside a built reality.
For this purpose, 44,500 tonnes of earth were moved within the 560 m long park, 150 trees were planted and a total of 42 small gardens were laid out on a 1.4 ha area. During the 12-year planning and construction period, the selection of perennials and shrubs was constantly adapted to the rapidly changing urban climate and the latest findings from the monitoring of soil management on the lid.
The park has reunited the formerly divided Hamburg district and already set numerous impulses in the active district life shortly after its ceremonial opening. The park above the formerly dividing motorway corridor has matured into a green district centre, an open space that connects people, brings them together and enhances the sense of life and values of an entire district.
Shortly after its completion, the park was christened with the name of Dorothea Buck, a sculptor from Schnelsen who campaigned for the destigmatisation of mentally ill people. The neighbourhood place called "Geschwister-Tölke-Platz" on Frohmestrasse, which is located within the park, is also named after people who were involved in a medical context and who lived in Schnelsen.
It is no coincidence that the naming of the square and park pays homage to people who have been socially committed, because this project also wants to and can make an impact in terms of both social and ecological sustainability.
Regaining a sense of belonging
Barrier-free encounter
XXL green roof
Urban gardening
Increase of biodiversity
In order to fully understand the regaining of a sense of belonging, it is necessary to take a detour into the history of the former village of Schnelsen. While the first documented mentions of "Senelse" date back to 1347, the Schnelsen School, which has stood on today's Frohmestraße since 1749 and is the focal point of Schnelsen for many citizens, is particularly important for the open space presented here. This former city centre is only 190 metres away from Geschwister-Tölke-Platz and the entrance to Dorothea-Buck-Park.
The construction of the A7 motorway from 1965-1968 changes the village character of Schnelsen brutally. The old village pond was filled in to make way for the Schleswiger Dam, and Schnelsen was divided into two parts, the only connection being the bridge over the A7 motorway in Frohmestraße. Today, this former road connection is marked by “POLAs” citizens' square.
Where once the city centre underwent a hard cut, today a place invites people to meet, exchange and spend time in the green - without the urge of "costly" consumption. "Neighbours" rediscover themselves as such, the park's long green axis is used as a car-free path connection to the north-west of Hamburg. The quality of this design also lies in the renewal of references that have been lost in the meantime. The removal of barriers, sometimes with the help of the reinterpretation of common (craft) techniques and design approaches, connects people more strongly with the place, ensures identification, "locates" and, in the best case, creates a sense of home.
In order to avoid duplication, later sections will present the extent to which this landscape architectural intervention works in the areas of accessibility, biodiversity and roof greening, and how it pays into the UN's sustainability goals.
By intervening in the built substance, Schnelsen has regained its real centre after more than 60 years - where transit traffic used to dominate the scene - and at the same time experiences a new sense of home.
Through a barrier-free design, the participation of diverse stakeholders in the public dialogue and the use of public space is made possible. At the same time, the design attempts to force the mobility turnaround by cutting back the dimensions of the former street space and instead enlarging the strolling areas along Frohmestraße and the newly created small gardens.
The hedges separating the allotment gardens from the general path are deliberately kept low to encourage the so-called "view over the garden fence". Social interaction between allotment gardeners and park visitors is explicitly desired.
The number of parking spaces provided is now smaller; at the same time, pedestrians and cyclists have been given more space for traffic and movement. A new kind of balance has been created.
In the area of plant selection, too, an attempt was made to meet the diverse demands of the user groups and at the same time to strengthen biodiversity in the urban space. For example, in the area of woody plants, varieties were chosen that on the one hand can withstand climatic changes and on the other hand can thrive on the special surface of a rooftop. At the same time, they were selected for their bird- and insect-friendliness and bring great visual diversity to the outdoor space through their variations in growth form, structure and height. The perennials were selected for robustness and longevity.
While on the one hand care was taken to use only native perennials, these must also be very insect-friendly and, through their variations, flower all year round in the park. Here, too, the ever-changing image of the park should constantly attract visitors, serve insects and increase biodiversity in an urban context.
By "fading out" the motorway in terms of design and developing this new public space, an upgrading of the historically based town centre was achieved, which can establish itself as a sustainable and lively place with its open space quality. The attractiveness of Schnelsen was permanently increased and the entire area revitalised.
In addition to a traffic situation optimised exclusively for cyclists, wheelchair users and pedestrians, a new green local centre was created where previously there was a "car traffic ditch".
Through an absolut barrier-free design, the participation of diverse stakeholder groups in this public space is made possible. In addition, barriers have been removed not only between people and nature but also among people. In particular, the Geschwister-Tölke-Platz as a neighbourhood square, where parties can be held if desired, a community plot and the elongated rows of small gardens along the edge of the tunnel encourage dialogue with "accidental" neighbours.
In the entire square and park area, there are no places that cannot be used or accessed by people with limited mobility. The design works with strong black and white contrasts so that impaired persons can orientate themselves well and safely in this space. The different choice of surfacing materials also ensures that different forms of movement, speeds and playability are permitted.
In addition, the special needs of disadvantaged groups were taken into account by the choice of furniture, for example by providing armrests or leaning facilities.
Overall, the various places in the park were not 'branded', which could have led to their use by specific user groups. The park thus allows free forms of play and use for all ages and people.
In the run-up to the competition in 2010, there was no special form of public participation, but afterwards the planning was presented regularly and during the process in various committees, public meetings and to all interested stakeholders.
The "Forum Kollau - Verein für die Geschichte von Lokstedt, Niendorf und Schnelsen e.V.", an association for the History of this area, has set itself the task of collecting, preserving, researching, exhibiting and communicating district history - with the aim of a diverse and lively exchange with young and old contemporaries. Accordingly, Forum Kollau has been a reliable partner in communicating the project progress of tunnel and park construction within the city. In its brochure ""Ohne Dach ist Krach" - Der lange Weg zum Schnelsener Autobahndeckel" ("Without a roof is noise" - the long road to the Schnelsen motorway lid), the association documents the 20-year construction period from the beginnings of the citizens' initiative in Bahrenfeld to the planting of the silver lime tree, where once there stood the city oak before the motorway was built. The Forum Kollau also understands the covering of the motorway as a building of the century that reunites Schnelsen and is of great importance for the neighbouring districts.
This re-established solidarity between the districts and their citizens creates trust and satisfaction, which can have a positive effect on the way people interact with each other. The course of the process has shown that these changes are much stronger if future users are kept informed early and constantly about the design process.
At the same time, the design with its park and neighbourhood square raises awareness - for the history of a city and the importance of natural space. The park as a bridge (over the motorway) may be understood ambiguously here: The redesign of the place creates identity and, through its high quality of stay, creates connections - both with each other and with nature.
The expansion of the A 7 motorway is triggering impulses for urban development in the Hamburg districts of Eimsbüttel and Altona that radiate far beyond the neighbouring areas. At the heart of the project are three tunnels in Schnelsen, Stellingen and Altona - the "Hamburg lids". These are intended not only to protect against noise, but also to offer citizens one thing above all: a better quality of life.
Where Hamburg wanted to realise more than the legally required noise protection, the city also had to participate in the financing. The costs were paid from the sale of municipal land, which is freed up for housing development by shifting green spaces and allotment gardens to the motorway lids.
The additional and already opened 560-metre-long lid in Schnelsen is currently being supplemented by the approximately 890-metre-long Stellingen federal lid. The lid in Altona is to be supplemented as the third construction phase over a distance of more than two kilometres, so that in Hamburg as a whole, approximately 3.5 kilometres of covered motorway and about 27 hectares of newly reclaimed green space will be created.
At the same time this noise protection project creates new residential space on about 60 hectares which are newly available for housing construction - due to noise reduction or because of the transfer of previous uses to the lids. There are development plans for more than 3,800 new flats as well as a large new sports facility in the Bahrenfeld district. Instead of sealing new areas, inner-city redensification can now be carried out on a grand scale.
As the first project to be implemented, the Schnelsen lid has a model and pilot character. The interest of planners and local authorities within Germany is immense, but even a delegation from Japan has already visited the project. The park on the motorway tunnel is contemporaneous as a major research project in the field of soil management, soil climatology, soil subsidence and water retention.
In addition to three representatives on the client's side and a contact person at the municipal approval authority, there was very intensive cooperation with the preliminary trades, first and foremost with the engineering firm Grassl GmbH, which carried out the static tests for the design of the tunnel surface. Bringing a total of 44,500 tonnes of earth, 150 trees and 42 small gardens onto a roof area 560 m long and about 34 m wide was absolutely new territory for all involved.
The cooperation with Krebs + Kiefer Ingenieure GmbH, who took care of the tunnel drainage and the implementation planning of the tunnel drainage, was correspondingly intensive. The particular planning challenge here was to provide enough water for the trees, shrubs and lawns on an area of 3.0 hectares, but at the same time to ensure that the water weight did not exceed the permissible total load or inadvertently make its way into the tunnel, while at the same time the tunnel had to be ventilated.
When it came to the planting environment and soil management, the planners from Melchior+wittpohl Ingenieurgesellschaft GbR did a great job. Already two years before the planned placement of the soil, the 44,500 tonnes of soil were stored externally and constantly monitored with regard to germ formation, soil subsidence and temperature development in the subsoil and topsoil. The results of the monitoring were discussed and changes in substrate thicknesses or soil compositions were decided in order to support the plants with an optimal soil in regard to the special environment and the constant climatic changes.
Without this close and time-intensive interdisciplinary cooperation of the various planning trades, the implementation of this mammoth task would not have been possible. Only through intensive joint research a common habitat for plants and animals, that is also capable of adapting to climatically changing living conditions, could be implemented on a roof top.
This landscape architecture project has only been handed over to the public four months ago. How many animal and insect species have become native to the 3.0 ha area or how well the plants adapted both to the special environment of a tunnel lid and to the climate changes will only become apparent in the coming years.
What has been proven, is the ability of this architectural intervention to screen street noise and exhaust odours from the park. So far, the trees and shrubs, perennials and grasses have grown very well and have not suffered any significant damage in their first winter on the roof top.
The outdoor space is used by very different groups of people throughout the day. While joggers tend to be active in the morning or evening hours, dog owners use the green space all day for their walks or cyclists choose to take shortcuts through the green. The gravelled areas invite people to play boules in the afternoons and at weekends, while on the grassy areas they can choose to kick footballs or fly kites. Because of the lack of 'branding' of the areas, they are used flexibly and quite differently.
Through the intervention, Schnelsen has regained its original centre and experienced a strengthening of the citizens' bond with the place. Inevitably, the encounter in the green also leads to a new bond between people who were previously separated by a four-lane motorway. The place that used to be avoided because of its noise and smell is now a meeting place for diverse target groups.
As predicted for the "Hamburg lid" project, this first completed construction already radiates far into the Schnelsen neighbourhood. The neighbouring streets have experienced a considerable upgrading; the structural redensification in the centre of Schnelsen has already begun. And last but not least, the idea of a much-needed change in mobility is gaining more and more support from resident, partly because the green space on their doorstep makes it easier to make the switch.
As described before, in the context of conversions or extensions of inner-city-motorways noise protection guidelines are usually met with noise protection walls or by following the minimum requirements of building law. Hamburg has gone much further with its “Hamburg lids”, not only by literally blocking out the noise caused by tunnel construction, but also by making some 27 ha of green and recreational space available to the residents of the Hanseatic city as a result.
It is not so much the long inner-city tunnel structures, but the greening and "playability" of the newly created outdoor spaces that have an extremely innovative character. Both the three guided tours as part of the Hamburg Day of Architecture 2022 and the ceremonial opening of the area in September last year were very well attended. The interest in the engineering achievement and the joy about the transformation of the site is great not only among the professional public, but also among Hamburg's population. Accordingly, the citizens' association of Schnelsen used the opening of the park as an occasion for the first of what will surely be many citizens' festivals on Geschwister-Tölke-Platz.
The partial financing of the project was certainly also innovative. By relocating parts of existing small gardens, previously located directly next to the motorway, to the parks on the lids, valuable inner-city building land was created. Thanks to the new lids and the reduced noise, Hamburg was able to designate and sell the new brownfield sites as such.
The period between winning the competition and completing the project is not without reason 12 years. Operating in a field that had never before been tackled in this way, at least not in Hamburg and probably not elsewhere in Europe, a classic planning service for a green roof was transformed into a collaborative research project involving various actors.
Constantly new findings, whether gained through own research or from the changing conditions outside (e.g. climate change), led to constant changes and adaptations of the own planning. At the same time, the process was determined by a constant balancing between necessity and possibility. How much design can the cover tolerate in its entirety? What do the different construction heights, wind loads and other influences allow? The discussions were held regularly and with all those involved in the process.
As a pilot project, the park will also be closely monitored and analysed after completion so that the findings can be directly incorporated into the planning of the other two Hamburg lids and possible follow-up projects elsewhere in Europe. I.e. the first transfer of knowledge to two other locations within Hamburg West is already being implemented.
In principle, the knowledge gained from the construction of the lid over the A7 motorway can be transferred to any project in which a multi-lane road is to be tunnelled over and then provided with a park on the roof of the tunnel. Naturally, the findings from this construction project must then always be adapted to the static conditions on site, to the climatic conditions and not least to the prevailing building law.
The beneficiaries are every resident next to a motorway that is hidden under a tunnel roof in favour of a park, as well as the more distant neighbourhood, which uses this new piece of greenery as a recreational area for itself. Cleaner air, less noise pollution and freely accessible attractive green space serves society as well as wildlife and plants.
Certainly, the redevelopment of Schnelsen's city centre does not solve the immense climate problems that the global community has to face. However, the city can take responsibility and make a contribution by increasing the attractiveness of using alternatives to private cars and thus promoting a mobility turnaround. This aspect pays off in terms of CO2 emission savings, as does the conscious choice of sustainable building materials and the planting of diverse trees and plants selected to increase biodiversity and defy climate change.
In the spirit of living more sustainably, many people are changing their diet and/or purchasing behaviour. Vegetarian products are constantly gaining market share, fish and meat consumption is decreasing and shoppers are increasingly turning to seasonal and regional fruit and vegetables. The availability of 42 private allotment gardens and one communal allotment gives many people the opportunity to grow their own food. The relationship to the product changes through the appreciation of one's own harvest. Not only adults but also their children learn how to grow food again.
In addition, the district of Schnelsen has been upgraded, creating not only good potential but also an attractive basis for inner-city redensification. This in turn addresses the lack of living space without sealing more (rural) land.
