1. General information
Location and description of the intervention
City or FUA
Stuttgart
Region
Europe
Native title of the NBS intervention
Begrünte Stadtbahngleise (Rasengleiskörper)
Short description of the intervention
Greened-over urban railway tracks (grass tracks) is a city-wide program in Stuttgart which assumes the construction of tram lines with grassed-over tracks. This applies not only to planning and construction but also long-term maintenance (ref 1).
Address

Implemented throughout the city
Stuttgart
Germany

Location
The NBS is a city-wide initiative, the GIS point marks the centre of the city
Type of area before implementation of the NBS
Central Business District / City Centre
Website of the intervention
https://nacto.org/wp-content/uploads/2016/04/3-7_Green-Tram-Tracks-The-Advantag…
Timeline of intervention
Start date of the intervention (planning process)
unknown
Start date of intervention (implementation process)
2010
End date of the intervention
ongoing
Present stage of the intervention
Ongoing
Goals of the intervention
1. Decrease in CO2 emissions;
2. Decrease the heat in the city center;
3. Revive the pedestrianism in the city;
4. Increase green space fraction in the roadsides;
5. Make the urban environment more comfortable and liveable for residents;
6. Reduction of noise reflection;
7. Increase in biodiversity (ref 1, 2, 4).
Quantitative targets
1. Decrease of reflection of road materials (albedo);
2. Decrease in noise in Hz (ref 1, 4).
Monitoring indicators defined
1. Average heat in °C;
2. Albedo, coefficient of reflectivity factor;
3. Square meters of new green areas;
4. number of trees planted (ref 1).
Sustainability challenge(s) addressed
Climate action for adaptation, resilience and mitigation (SDG 13)
Climate change mitigation
Green space, habitats and biodiversity (SDG 15)
Green space creation and/or management
Environmental quality
Air quality improvement
Noise reduction
Regeneration, land-use and urban development
Regulation of built environment
Climate change mitigation: What were the goals of the NBS?
Sequester and store carbon
Climate change mitigation: What activities are implemented to realize the conservation goals and targets?
Install vertical or horizontal artificial surfaces that help with carbon storage and cooling
Implementation activities
1. Maintainance and expansion of green spaces along the tram tracks
2. Improving the sidewalks for pedestrians
3. Introduction of high reflection building and road materials, high reflection points for vehicles
4. Planting new trees (ref 1, 2)
Type of NBS project
Creation of new green areas
NBS domain and interventions
Ecological domain(s) where the NBS intervention(s) is/are implemented
Grey infrastructure featuring greens
Railroad bank and track greens
Vegetation Type
Grass
Shrubs
Amenities offered by the NBS
Unknown
Services
Expected ecosystem services delivered
Regulating services
Local climate regulation (temperature reduction)
Air quality regulation
Carbon storage/sequestration
Habitat and supporting services
Maintenance of genetic diversity
Cultural services
Aesthetic appreciation
Scale
Spatial scale
Meso-scale: Regional, metropolitan and urban level
Beneficiaries
Primary Beneficiaries
Citizens or community groups
Governance
Governance arrangements
Government-led
Please specify the roles of the specific government and non-government actor groups involved in the initiative
Tram companies operating in Stuttgart, for example, Stuttgarter Straßenbahnen AG (SSB). (ref 5)
Key actors - initiating organization
Local government/municipality
Private sector/corporate actor/company
Land owners
Public space owned by the city
Key actors - Other stakeholders involved (besides initiating actors)
Local government/municipality
Private sector/corporate actor/company
Land owners
Public space owned by the city
Participatory methods/forms of community involvement used
Unknown
Policy drivers
NBS intervention implemented in response to an Regional Directive/Strategy
Yes
Please specify the "Regional Directive/Strategy"
1. UN Framework Convention on Climate Change (ref 2)
NBS intervention implemented in response to a national regulations/strategy/plan
Yes
Please specify the national regulations/strategy/plan
1. The “Act on the Prevention of Harmful Effects on the Environment Caused by Air Pollution, Noise, Vibration and Similar Phenomena” (or in short BImSchG –Federal Immission Control Act) (1) The BImSchG regulates the admissibility of plants and products using factors such as emission limits, which in the final reckoning does reduce the release of substances damaging to the climate.
2. "Development Planning Act" (Building Code). Within the framework of development planning, landscape and green space plans are used as a way of implementing the objectives of nature and landscape conservation. These encompass an inventory of natural conditions in the relevant area and the claims made for its use (ref 1, 2).
NBS intervention implemented in response to a local regulation/strategy/plan
Yes
Please specify the "local regulation/strategy/plan"
1. Stuttgart’s urban climate protection scheme (KLIKS). The State Capital Stuttgart is currently undertaking a whole range of measures aimed at reducing greenhouse gases. These endeavors have been successfully implemented over a period of several years. One significant way in which to approach the adjustment process is by taking the climate into account in local urban planning (ref 1)
Mandatory or voluntary intervention
Mandatory (based on policy)
Intervention is mandatory
Spatial planning guidance
Spatial planning law
Environmental regulation
Energy regulation
Building regulation
Enablers
Presence of specific city-level GI/NBS vision/strategy/plan - mentioned in connection to the project
Unknown
Presence of specific city-level GI/NBS section/part in a more general plan - mentioned in connection to the project
Yes
Please specify the general plan with GI/NBS section
1. Stuttgart’s urban climate protection scheme (KLIKS). The State Capital Stuttgart is currently undertaking a whole range of measures aimed at reducing greenhouse gases. These endeavors have been successfully implemented over a period of several years. One significant way in which to approach the adjustment process is by taking the climate into account in local urban planning (ref 1)
If there is a relevant strategy or plan, please specify the theme / type of the plan.
City specific climate change policy or plan
Presence of city network or regional partnerships focused on NBS - mentioned in connection to the project
Yes
Please specify
The green rail network (Grüngleisnetzwerk) is a grouping of innovative small and medium-sized enterprises (SMEs), large companies, transport companies and research facilities in German cities. It combines the research and development capacities of the participating companies, their application-related knowledge and the know-how from various research facilities.The focus is on the development of innovative system solutions for the intensive and extensive greening of street lanes It supports the railway greening in Stuttgart (ref 6)
Presence of GI / NBS research project - mentioned in connection to the project
Yes
Please specify
The Klimaatlas offers a written description of the city climate supported by planning recommendations and analysis maps at a 1:20,000 scale, a scale that corresponds to that of the city’s land use maps. The analysis maps identify ‘climatopes’ defined by daily variation in thermal energy, a vertical roughness of the land, topographical position, and type of land use. Stuttgart identifies eleven climatopes: water, open land, forest, greenbelt, garden city, city periphery, city, core city, commercial, industry, and railway land. In particular, "railway climatope" was identified. Each has a climatic role with planning implications (ref 2).

Subsidies/investment for GI / NBS in the city - mentioned in connection to the project
Unknown
Co-finance for NBS
Yes
Co-financing governance arrangements
Yes
Co-governance arrangement
Other
Please specify other co-financing type
Corporate
Was this co-governance arrangement already in place, or was it set up specifically for this NBS?
Unknown
Financing
Total cost
Unknown
What is/was the Cost/Budget (EUR) of the NBS or green infrastructure elements?
Unknown
What are the total amount of expected annual maintenance costs?
Unknown
What is the expected annual maintenance costs of the NBS or GI elements?
Unknown
Please specify cost savings
Unknown
Please specify total cost (EUR)
Unknown
Source(s) of funding
Public local authority budget
Corporate investment
Type of fund(s) used
Earmarked public budget
Direct funding (grants, subsidies, or self-financed projects by private entities)
Non-financial contribution
Unknown
Business models
Green densification model
Vacant space model
Please specify other environmental impact
Water retention during precipitation
Which of the involved actors was motivated by this model?
Public actor (e.g. municipality)
Type of innovation
Technological
Infrastructural innovation
Please specify technological innovation
The practice of green railway tracks is new for the integrated development strategy of the city of Stuttgart.
Novelty level of the innovation
The innovation is copied/derived from previous initiative(s) with substantial adaptation
Please specify novelty level of the innovation
The practice of green railway tracks isn’t exactly new, it was first used in Liverpool in 1924 (3). In Germany, the green railway tracks were firstly introduced already in Freiburg in 1983. During the discussions on the implementation fo the similar policy in Stuttgart, this example was referenced (5).
Replicability/Transferability
The innovation is transferred to new initiative(s) with substantial adaptation
Please specify Replicability/Transferability
Grass tram routes have become more prevalent over the past 10 years throughout Europe, as well as outside. For instance, in the city of Kagoshima in Japan (3). However, not always this measure is grounded on such wide-scale environmental regulations, such as in Stuttgart.
Impacts, benefits
Environmental impacts
Climate change
Enhanced carbon sequestration
Environmental quality
Improved air quality
Reduced noise exposure
Water management and blue areas
Improved stormwater management
Green space and habitat
Increased green space area
Increased number of species present
Other
Description of environmental benefits
1. The project has increased the overall green space in the city;
2. Some of the sedum planted are evergreen species which will help in keeping the tracks green even in winter;
3. These provide habitat for innumerable insects and other invertebrates;
4. The extensive vegetation systems retain 50 % of precipitation and the intensive vegetation systems retain 70 % up to 100 %.;
5. During winter the dust coverage on the leaves reaches up to 100 % helping in pollution reduction;
6. The materials used can absorb 500 - 1000 Hz of noise.;
7. The rail temperature in grass and sedum track remains within 25-30 °C;
8. Local contaminants of the air can deposit on the vegetation surface of tram track greening. The contaminants are partially bound and metabolised by the plants. (ref 3)
Economic impacts
Generation of income from NBS
Description of economic benefits
1. Studies indicate that 12 % of the customers are willing to pay higher prices in greened business areas. This could help the city to earn more by controlling the price for traveling and tickets. (ref 4)
Social and cultural impacts
Social justice and cohesion
Improved access to urban green space
Health and wellbeing
Improved physical health
Improved mental health
Description of social and cultural benefits
1. The optical valuation of green tram track influences social and mental health of humans. 2. The physical health of the locals has improved with the contribution from the sedum in absorbing the pollutant from the air. (ref 1, 5)
Type of reported impacts
Expected impacts
Achieved impacts
Indicators
Kms of new green tram track, pollutant absorption and water retention. (ref 3)
Environmental, social and economic impacts
Climate action for adaptation, resilience and mitigation (SDG 13)
Green space, habitats and biodiversity (SDG 15)
Environmental quality
Regeneration, land-use and urban development
Health and well-being (SDG 3)
Analysis of specific impact categories
Job creation: The NBS created ...
No information available
Negative impacts: Did the project cause any problems or concerns?
No information was found regarding negative impacts of the project
COVID-19 pandemic
Unknown as of September, 2020.
Methods of impact monitoring
Process of recording NBS impacts
Conduct a baseline survey before and after NBS implementation
Methods used to evaluate the impacts of NBS
Measurements of biophysical aspects of the NBS (e.g. temperature, water flow)
Evidence for use of assessment
Presence of an assessment, evaluation and/or monitoring process
Unknown
Presence of indicators used in reporting
No evidence in public records
Presence of monitoring/evaluation reports
No evidence in public records
Availability of a web-based monitoring tool
No evidence in public records
Impact assessment mechanism
Name of any specific impact assessment tools
unknown
Link to the output of assessments
https://www.research.manchester.ac.uk/portal/files/33527689/FULL_TEXT.PDF
Use of GIS in mapping impacts
Yes
Citizen involvement
Citizens involvement in assessment/evaluation
Yes
Mode(s) of citizen involvement in evaluation/assessment
Questionnaire
Citizens involvement in the analysis of the assessment/evaluation
Unknown
Follow-up to the evaluation / assessment
Unknown
References
Web links relevant to the intervention
Green Transport: The Grass Tramway of Kagoshima
Green Tram Tracks
VerkehrGrüne Gleise gegen Lärm und Feinstaub
Wirkung und Funktion Grüner Gleise
Documents relevant to the intervention
Attachment Size
Climate change – challenge facing urban climatology (1.46 MB) 1.46 MB
Towards a Liveable Urban Climate: Lessons from Stuttgart (1 MB) 1 MB
List of references
1. Office of Urban Planning and the Environment. (2010). Climate change – challenge facing urban climatology. State Capital Stuttgart. Office of Urban Planning and the Environment. Environmental Protection Office. Section of Urban Climatology. In association with the Communication Department.
2. Michael Hebbert, Brian Webb. (2007). Towards a Liveable Urban Climate: Lessons from Stuttgart, Available at: https://www.research.manchester.ac.uk/portal/files/33527689/FULL_TEXT.PDF. Accessed on 23rd September, 2020.
3. Tom Moran. (2013). Green Transport: The Grass Tramway of Kagoshima, Available at: http://www.urbanghostsmedia.com/2013/06/green-transport-grass-tramway-kagoshima/. Accessed on 23rd September, 2020.
4. Hendrikje Schreiter (2010). Green Tram Tracks, Available at: https://nacto.org/wp-content/uploads/2016/04/3-7_Green-Tram-Tracks-The-Advantages-of-Implementing-Vegetation-Systems-in-Tram-Tracks_2010.pdf. Accessed on 23rd September, 2020.
5. (2010). VerkehrGrüne Gleise gegen Lärm und Feinstaub, Available at: http://www.stuttgarter-nachrichten.de/inhalt.verkehr-gruene-gleise-gegen-laerm-und-feinstaub.9f36a9fa-2ad5-4582-b87f-7d849740f285.html. Accessed on 23rd September, 2020.
6. Wirkung und Funktion Grüner Gleise, Available at: http://www.gruengleisnetzwerk.de/images/downloads/wirkung.pdf. Accessed on 23rd September, 2020.
Comments and notes
Comments
1. In order to reduce water requirement and the level of care needed during the anticipated extended
periods of drought and heat, plant species will be chosen which have greater resistance to dry conditions (1).
2. Also worthy of mention is an experiment carried out by the tram company Stuttgarter Straßenbahnen AG (SSB) involving the use of turf to retroactively green over existing ballast and sleeper tracks. The experimental area is located in Olgaeck at the junction of the U 15 line into Alexanderstraße. Should this method prove successful, then it would be possible to green over not only new
track sections but also suitable stretches of existing stock (1).
Additional insights
The project is still ongoing, so no final evaluation conducted so far. however, climatope analysis provided the basis for spatial planning recommendations of the project. With pixels of up to 100 meters, the planning maps are not detailed enough to apply to the individual lot level, but they provide neighbourhood-level guidance, and a basis for localized micro climatic appraisal where necessary (2).
Pictures of the NBS
/sites/default/files/nbs/images/snimok_ekrana_2017-07-12_v_14.58.07.png
Public Images
Green Tram Track
Stadtklima Stuttgart
https://www.stadtklima-stuttgart.de/stadtklima_filestorage/download/AfU-Heft-3-2010-Web.pdf