Green Ventilation Corridors

1. General information

Location and description of the intervention

City or FUA

Stuttgart

Region

Europe

Native title of the NBS intervention

Grüne Belüftungskorridore

Short description of the intervention

The Green Ventilation Corridors network in Stuttgart, Germany is an implemented nature-based solution coupled with regulatory policies and incentives. Within this initiative, Green ventilation corridors were created to enable fresh air to sweep down from hills surrounding the city (4).

Address

Introduced systematically around the whole 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

http://climate-adapt.eea.europa.eu/metadata/case-studies/stuttgart-combating-th…

Timeline of intervention

Start date of the intervention (planning process)

1992

Start date of intervention (implementation process)

1998

End date of the intervention

2014

Present stage of the intervention

Completed

Please specify "other" stage of the intervention

The intervention started with the adoption of the Regional Plan of Stuttgart in 1998 that assumed first regulations in relation to green air corridors (5).

2. Objectives of the intervention

Goals of the intervention

1. Preserve and channel cool air throughout the city (1)
2. Connecting rural areas with the city center (1)
3. Prevent urban heat island effect and poor air quality (2)
4. Enhance biodiversity (2)
5. Support health and wellbeing of citizens providing more recreational spaces (5)

Quantitative targets

Unknown

Monitoring indicators defined

1. Annual CO2 emissions in tons
2. Average temperature in °C
3. Square meters of new green urban areas
4. Overall thermal stress in % (8)

Sustainability challenge(s) addressed

Climate action for adaptation, resilience and mitigation (SDG 13)

Climate change mitigation

Green space, habitats and biodiversity (SDG 15)

Habitat and biodiversity restoration

Green space creation and/or management

Environmental quality

Air quality improvement

Noise reduction

Inclusive and effective governance (SDG 16)

Effective management

Health and well-being (SDG 3)

Creation of opportunities for recreation

Climate change mitigation: What were the goals of the NBS?

Sequester and store carbon

Reduce energy demand, with the use of renewables or energy efficiency improvements

Climate change mitigation: What activities are implemented to realize the conservation goals and targets?

Increase green urban nature for carbon storage (wetlands, tree cover)

Improve carbon sequestration through selection of more adaptable species

What types of restoration goals are / were defined for the NBS intervention?

Species-focused

What activities are implemented to realize the restoration goals and targets?

Restore species (native, endangered, or unspecified)

Restore ecological connectivity

Implementation activities

The following implementation activities have taken place;
1. Production of the urban climatic map
2. Introduction of new building regulations
3. Creation of the climate-relevant ventilation lanes, parks and green corridors (5, 7)

Type of NBS project

Creation of new green areas

3. NBS domains, ES and scale

NBS domain and interventions

Ecological domain(s) where the NBS intervention(s) is/are implemented

Grey infrastructure featuring greens

Alley or street trees and other street vegetation

Railroad bank and track greens

Green parking lots

Parks and urban forests

Pocket parks/neighbourhood green spaces

Green corridors and green belts

Vegetation Type

Grass

Shrubs

Trees

Please specify how many trees were planted

65,000 trees in parks and open spaces and 35,000 street trees (7)

Amenities offered by the NBS

Benches and drinking water stations

Playgrounds

Services

Expected ecosystem services delivered

Regulating services

Local climate regulation (temperature reduction)

Air quality regulation

Noise reduction

Carbon storage/sequestration

Habitat and supporting services

Habitats for species

Maintenance of genetic diversity

Cultural services

Aesthetic appreciation

Recreation

Scale

Spatial scale

Meso-scale: Regional, metropolitan and urban level

Beneficiaries

Primary Beneficiaries

Citizens or community groups

4. Governance and financing

Governance

Governance arrangements

Government-led

Please specify the roles of the specific government and non-government actor groups involved in the initiative

Verband Region Stuttgart (the association of regional cities and municipalities) and the City of Stuttgart. The Section of Urban Climatology within the Office for Environmental Protection of the City of Stuttgart contributed with its specialist knowledge. The evaluation and processing of the data for drawing up of the basic material required to produce the maps were undertaken by an external specialist consultant. (1)

Key actors - initiating organization

Local government/municipality

Land owners

Public space owned by the city

Key actors - Other stakeholders involved (besides initiating actors)

EU body

National government

Regional government

Local government/municipality

Land owners

Public space owned by the city

Participatory methods/forms of community involvement used

Dissemination of information and education

Policy drivers

NBS intervention implemented in response to an Regional Directive/Strategy

Unknown

NBS intervention implemented in response to a national regulations/strategy/plan

Unknown

NBS intervention implemented in response to a local regulation/strategy/plan

Yes

Please specify the "local regulation/strategy/plan"

The Regional Plan of Stuttgart (1998) illustrated a system of open-space corridor that channel cooler air down preserved, undeveloped park areas on hillsides and through low-density developed areas, connecting rural areas and the city center. Within the city, shaded parks are connected to the air flow channels wherever possible, providing cooling for local neighborhoods (1). Land use within the green corridors and on the slopes is strictly regulated; the preferred width is a minimum of 100 m (1).

Mandatory or voluntary intervention

Mandatory (based on policy)

Intervention is mandatory

Spatial planning guidance

Environmental regulation

Building regulation

Enablers

Presence of specific city-level GI/NBS vision/strategy/plan - mentioned in connection to the project

Yes

Please specify

Stuttgart Cool City Program. The primary objective of Stuttgart's current urban framework plan is to preserve and enhance cohesive green corridors in a dwelling and partly built-up areas of open land on hillside sites. Due to the heat produced by the industrial activity in the city, trees are planted and green areas are created to enhance airflow and overall air quality in the city (7).

Presence of specific city-level GI/NBS section/part in a more general plan - mentioned in connection to the project

Unknown

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

ICLEI – Local Governments for Sustainability is the world’s leading network of over 1,500 cities, towns, and metropolises committed to building a sustainable future. Aims: to make their cities sustainable, low-carbon, resilient, biodiverse, resource-efficient, healthy and happy, with a green economy and smart infrastructure (2). The project of Stuttgart green ventilation corridors was mentioned in the ICLEI briefing sheet and encouraged to be implemented in other cities.

Presence of GI / NBS research project - mentioned in connection to the project

Yes

Please specify

Liu Shuyu, Shen Jihuang. (2015). Urban Ventilation Corridor Planning Method Based on the Local Circulation – Taking Stuttgart, Germany as an example [J]. Journal of Zhejiang University: engineering science edition, 2010, 44 (10): 1985-1991. (11)

Subsidies/investment for GI / NBS in the city - mentioned in connection to the project

Yes

Please specify

The project was funded by the City of Stuttgart and the Verband Region Stuttgart (11)

Co-finance for NBS

Co-financing governance arrangements

Was this co-governance arrangement already in place, or was it set up specifically for this NBS?

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 regional budget

Public local authority budget

Type of fund(s) used

Direct funding (grants, subsidies, or self-financed projects by private entities)

Non-financial contribution

Unknown

Business models

Green densification model

Which of the involved actors was motivated by this model?

Public actor (e.g. municipality)

5. Innovation

Type of innovation

System innovation

Please specify system innovation

The Stuttgart network of Green Ventilation Corridors is one of the first systemic NBS for cooling of cities and improving overall environmental qualities (11).

Novelty level of the innovation

The innovation is completely new without connections to previous initiative(s)

Please specify novelty level of the innovation

Stuttgart is considered as a pioneering city in Germany in regard to an implementation of a city-level green corridor ventilation NBS (2).

Replicability/Transferability

The innovation is transferred to new initiative(s) with substantial adaptation

Please specify Replicability/Transferability

Stuttgart experience was studied and partially used in China, Shenzhen case (11)

6. Evaluation and learning

Impacts, benefits

Environmental impacts

Climate change

Lowered local temperature

Enhanced carbon sequestration

Environmental quality

Improved air quality

Green space and habitat

Increased green space area

Increased ecological connectivity across regeneration sites and scales

Description of environmental benefits

1. "Over 39% of Stuttgart’s surface area has been put under the protection of nature conservation orders … greenery covers more than 60% of the city. Stuttgart contains 5,000 hectares of forests and woodland, 65,000 trees in parks and open spaces and 35,000 street trees. 300,000 square meters of rooftops have been greened and [more than] 40 out of 250 kilometres of tram tracks have been grassed. In line with the city development vision, 60 hectares of greenfield land previously earmarked for development has been cut from the 2010 land development plan to protect existing green space".
2. The many and various efforts to reduce pollutant and nutrient inputs into ecosystems by means of environmental legislation also support the conservation of habitats and biodiversity.
3. Compilation of detailed information about the area’s topography, climate and land use allows for precise planning for different areas, which together aim to improve air quality and mitigate the urban heat island effect.
4. Targeted interventions such as a building ban in the hills around the town, and prevention of building projects that might obstruct the ventilation effect of nocturnal cold-air flows have resulted in preservation and enhancement of air exchange and cool air flows in the city. (1, 5, 7)

Economic impacts

Unknown

Description of economic benefits

Unknown

Type of reported impacts

Expected impacts

Achieved impacts

Indicators

60 hectares of greenfield land previously earmarked for development has been cut from the 2010 land development plan to protect existing green space, average temperature control during the summer months, the total number of new trees planted. (12)

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

Inclusive and effective governance (SDG 16)

Health and well-being (SDG 3)

Sustainable consumption and production (SDG 12)

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

Collection of monitoring data continuously throughout the project to aid evaluation

Methods used to evaluate the impacts of NBS

Focus groups

GIS data analysis

Observation (including virtual surveillance methods)

Evidence for use of assessment

Presence of an assessment, evaluation and/or monitoring process

Yes

Presence of indicators used in reporting

Yes

Presence of monitoring/evaluation reports

Yes

Link to monitoring/evaluation reports

http://climate-adapt.eea.europa.eu/metadata/case-studies/stuttgart-combating-th…

Availability of a web-based monitoring tool

No evidence in public records

Impact assessment mechanism

Name of any specific impact assessment tools

1. The study of Baden-Württemberg region showing the effect of built-up land cover, including roads and railroads, on landscape fragmentation (Source: Institute of Landscape Planning and Ecology, University of Stuttgart) (3). See 'additional comments' for additional info.

2. Thermal maps are the other example of the impact assessment mechanism. They illustrate the results of the measuring flights which allow for a snapshot of the temperature distribution and for the identification of temperature differences in different parts of the city (5).

Link to the output of assessments

https://ugecviewpoints.wordpress.com/2016/01/12/structure-and-agency-the-seeds-…

Use of GIS in mapping impacts

Yes

Citizen involvement

Citizens involvement in assessment/evaluation

Unknown

Citizens involvement in the analysis of the assessment/evaluation

Unknown

Follow-up to the evaluation / assessment

Unknown

7. Sources

References

Web links relevant to the intervention

Structure and agency: The seeds of sustainability for 21st century cities

HOW CITIES ARE USING NATURE-BASED SOLUTIONS FOR SUSTAINABLE URBAN DEVELOPMENT

STUTTGART: COOL CITY

Urban Climate in Stuttgart Ventilation corridors and green in the city

German Strategy for Adaptation to Climate Change

Stuttgart Region: Multifunctional Green Infrastructure for an Attractive Urban …

Stuttgart, Germany: green ventilation corridors

List of references

1. DeKay. M. and Brown. G.Z. (2013) Sun, Wind, and Light: Architectural Design Strategies. John Wiley & Sons.
2. (2017). ICLEI Briefing Sheet - Nature-based Solutions, Available at: http://unfccc.int/files/parties_observers/submissions_from_observers/application/pdf/778.pdf. Accessed on 20th September, 2020.
3. UGEC Viewpoints. (2016). Structure and agency: The seeds of sustainability for 21st-century cities, Available at: https://ugecviewpoints.wordpress.com/2016/01/12/structure-and-agency-the-seeds-of-sustainability-for-21st-century-cities/. Accessed on 20th September, 2020.
4. ICLEI. (2017). HOW CITIES ARE USING NATURE-BASED SOLUTIONS FOR SUSTAINABLE URBAN DEVELOPMENT, Available at: http://cbc.iclei.org/cities-using-nature-based-solutions-sustainable-urban-development/. Accessed on 20th September, 2020.
5. Edward Ng and Chao Ren (no date) The Urban Climatic Map: A Methodology for Sustainable Urban Planning. Routledge, Available at: https://books.google.com.tr/books?id=vDmDCgAAQBAJ&pg=PT541&lpg=PT541&dq=ventilation+green+corridor+stuttgart&source=bl&ots=AIW3rWlnQh&sig=BKWGfGBXKPSNFcQLJfXv_dj3_9I&hl=ru&sa=X&ved=0ahUKEwj40O35m4PVAhUsJJoKHZ1OC2gQ6AEIczAM#v=onepage&q=ventilation%20green%20corridor%20stuttgart&f=false. Accessed on 20th September, 2020.
6. Danish Architecture Centre (2017). STUTTGART: COOL CITY. Dac&Cities, Available at: http://www.dac.dk/en/dac-cities/sustainable-cities/all-cases/green-city/stuttgart-cool-city/
7. CIRCLE2 (2013). Urban Climate in Stuttgart Ventilation corridors and green in the city, Available at: http://www.circle-era.eu/np4/%7B$clientServletPath%7D/?newsId=519&fileName=8_CIRCLE_2_ECCA_Ventilation_corridors_Ul.pdf. Accessed on 20th September, 2020.
8. German Federal Government (2008). German Strategy for Adaptation to Climate Change, Available at: http://www.preventionweb.net/files/27772_dasgesamtenbf1-63.pdf. Accessed on 20th September, 2020.
9. Oppla Case Study (2017). Stuttgart Region: Multifunctional Green Infrastructure for an Attractive Urban Region, Available at: http://oppla.eu/casestudy/17477. Accessed on 20th September, 2020.
10. Liu Shuyu, Shen Jihuang. (2015). Urban Ventilation Corridor Planning Method Based on the Local Circulation – Taking Stuttgart,
Germany as an example [J]. Journal of Zhejiang University: engineering science edition, 2010, 44 (10): 1985-1991.
11. CEEWeb (2017). Stuttgart, Germany: green ventilation corridors. Available at: http://www.ceeweb.org/work-areas/priority-areas/green-infrastructure/climate/. Accessed on 20th September, 2020.
13. Antony Mwangi Wambui (2012). Towards “Cool Urbanity”: Green Infrastructure and City Form Spatial Realignment for Natural Ventilation. Department of Landscape Architecture. College of Design. North Carolina State University.

Attachments

Attachment	Size
NBS Stuttgart example (3.73 MB)	3.73 MB
Towards “Cool Urbanity”: Green Infrastructure and City Form Spatial Realignment for Natural Ventilation (3.78 MB)	3.78 MB

Additional comments

1. Section 6 (Impact assessment tools).

The German state of Baden-Württemberg studied the extent to which its physical development, built-up land cover, and location of other barriers (e.g., roads and railroads) had fragmented its landscape. Its findings showed that large green patches of natural habitat had been degraded and destroyed—with detrimental effects on other species that depend on relatively uninterrupted areas for mating, resource, gathering, etc—far more extensively than previously thought

Interview comments

Since 1992, a scheme has been in place for Stuttgart residents to adopt a tree within the newly introduced green spaces. Today some 182 caretakers have adopted almost 500 trees. They are responsible for watering the tree, reporting pest attacks, removing the leaf litter and fallen branches, and protecting the tree from dog fouling (13). Planting new trees is an important step in cooling the city.

Comments and notes

Comments

1. Section 6 (monitoring/evaluation).

The Climate Atlas for the region of Stuttgart was published in 2008, based on the previous work in this area carried out by the City of Stuttgart since the 1980s and the in-house urban climatology department (in existence in the City of Stuttgart since 1938). The Climate Atlas provides standardized climatic assessments for the 179 towns and municipalities in the Stuttgart region. The Atlas comprises maps which show regional wind patterns, flows of cold air, air pollution concentrations, and other relevant information required to inform planners on what to do for urban climatic optimization that could inform new projects and retrofits. A key element of the Atlas is an area classification based on the role that different locations play in air exchange and cool airflow in the Stuttgart region, based on topography, development density and character, and provision of green space.

Additional insights

Recent research in the sphere of climate change influences the implementation of the Green Ventilation Corridors NBS. According to the Intergovernmental Panel on Climate Change (IPCC), there is a “very high probability” (i.e. a probability of over 90
percent) that the greater part of the warming observed since 1950 is due to human activities. Moreover, in 2007 the IPCC stated in its Fourth Assessment Report that means temperatures in the northern hemisphere for the second half of the 20th century were very probably higher than for any other 50-year period during the last 500 years and were probably the highest in at least
the last 1300 years (9). The project was funded by the City of Stuttgart and the Verband Region Stuttgart and emerged as an implementation of recommendations made in the Climate Atlas for the region of Stuttgart. The project itself was implemented by the Office of Urban Planning and Urban Renewal, with support from the Office for Urban Protection (12).

Pictures of the NBS

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Public Images

Climate Adapt

https://climate-adapt.eea.europa.eu/metadata/case-studies/stuttgart-combating-the-heat-island-effect-and-poor-air-quality-with-green-ventilation-corridors/#cost_benefit_anchor