1. General information
Location and description of the intervention
City or FUA
Bonn
Region
Europe
Native title of the NBS intervention
Umgestaltung des Rheindorfer Baches in Auerberg und Graurheindorf
Short description of the intervention
The 18 km long Rheindorfer stream flowing into the Rhine has faced increased urbanization, industrial activity and surface sealing over the last decades of the 20th century. As a result, numerous interventions were made to its original structure, such as the creation of a concrete bed for the stream and the straightening of the stream course. Meanwhile, an increasing amount of pressure was put on its water carrying capacity. In order to improve the flood retention capacity of the stream, the renaturalization project of the stream was executed in some parts of the water body. The project aims were 1) to restore the natural course of the stream and the state of the riverbeds, thus enhancing the stream's capacity to buffer floods, 2) restore the natural biodiversity of the floodplain and 3) to create a recreational area for locals (1,2).
Address

Bonn
Germany

Location
The NBS is situated in an area, with clear delineation of boundaries and a specific shape (polygon). The NBS project can also have more than one area location (more than one polygon, situated close by).
Area boundary
POINT (7.085865 50.752402)
POINT (7.086241 50.752531)
POINT (7.08579 50.754004)
POINT (7.084674 50.754981)
POINT (7.084159 50.754716)
POINT (7.085189 50.753073)
Type of area before implementation of the NBS
Residential
Public Greenspace Area
Website of the intervention
http://www.bonn.bund.net/themen_und_projekte/geocaching/tour_nord/7_rheindorfer…
Timeline of intervention
Start date of the intervention (planning process)
unknown
Start date of intervention (implementation process)
2001
End date of the intervention
2002
Present stage of the intervention
Completed
Goals of the intervention
1. Increase the retention capacity of the stream during high water levels of the Rhine (1);
2. Recreational space for residents (1);
3. Ecological enhancement of the area and conservation of the tree population (1).
Quantitative targets
1. Creation of 5,000 cubic metres of additional retention area in case of flooding of the Rhine in terms of natural floodplains (2);
2. Seeding of over 2,000 trees (varied tree species), reseeding an area of 3,600 sqm (1).
Monitoring indicators defined
Unknown
Sustainability challenge(s) addressed
Water management (SDG 6)
Flood protection
Stormwater and rainfall management and storage
Improvements to water quality
Green space, habitats and biodiversity (SDG 15)
Green space creation and/or management
Regeneration, land-use and urban development
Promote natural styles of landscape design for urban development
Health and well-being (SDG 3)
Creation of opportunities for recreation
Implementation activities
1. The Rheindorfer stream was freed from its concrete structure and shell (2).
2. Transformation of the straight course of the stream into a curvy course and thus extending the total length of the stream. (2)
3. Plantation of 2,000 different trees and new seeds covering 3,600 sqm, out of which 600 sqm is grassland (1).
4. Creation of a natural floodplain by flattening the riverbeds and the embankments. (2)
With these measures, the capacity of the stream as a water retention area was enlarged by 5,000 to a total capacity of 17,000 cubic metres of capture. An additional aim was the reintroduction of natural habitat to improve its provision of ecosystem services (2).
Type of NBS project
Creation of semi-natural blue areas
Ecological restoration of ecosystems
Management and improved protection of rivers and other blue areas
NBS domain and interventions
Ecological domain(s) where the NBS intervention(s) is/are implemented
Grey infrastructure featuring greens
Riverbank/Lakeside greens
Blue infrastructure
Rivers/streams/canals/estuaries
Vegetation Type
Grass
Shrubs
Trees
Please specify how many trees were planted
2000
Amenities offered by the NBS
Benches and drinking water stations
Services
Expected ecosystem services delivered
Provisioning services
Water (surface and ground water for drinking and non-drinking purposes)
Regulating services
Flood regulation
Water purification / filtration
Habitat and supporting services
Habitats for species
Scale
Spatial scale
Micro-scale: District/neighbourhood level
Beneficiaries
Primary Beneficiaries
Local government/Municipality
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
The project was designed and implemented by the local water authority (city of Bonn) (1).
Key actors - initiating organization
Local government/municipality
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"
European Water Framework Directive issued in 2000 (integrated water management concept including the preservation of water- and land-related ecosystem services), which in Germany was translated into the following national laws: "Wasserhaushaltsgesetz" and the "Landeswassergesetz" (translated: water regime law, national water law) (4)
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"
"Bachentwicklungsplan" (English: River Development Plan) issued by the city council of Bonn in 1988 (4)
"Hochwasserschutz-Konzept" (English: Flood Risk Management Concept) issued by the city council of Bonn in 1997 (5)
Mandatory or voluntary intervention
Mandatory (based on policy)
Intervention is mandatory
Other
Please specify other type of mandatory intervention
mandatory by the EU Water Framework Directive
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
Unknown
Presence of city network or regional partnerships focused on NBS - mentioned in connection to the project
Unknown
Presence of GI / NBS research project - mentioned in connection to the project
Yes
Please specify
in the 1980s the city council Bonn was aware of the poor ecological condition of several rivers and therefore commissioned an investigation of the river qualities: next to the low water quality, the concrete walls were criticized which prevent species from thriving which require diversity of ecosystems and substrates (1).
Subsidies/investment for GI / NBS in the city - mentioned in connection to the project
Unknown
Co-finance for NBS
Yes
Co-financing governance arrangements
Unknown
Was this co-governance arrangement already in place, or was it set up specifically for this NBS?
Unknown
Financing
Total cost
€100,000 - €500,000
What is/was the Cost/Budget (EUR) of the NBS or green infrastructure elements?
490,000
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)
490,000 Euros total cost, of which 65 percent were funded by the federal government of North-Rhine-Westphalia (1,2).
Source(s) of funding
Public regional budget
Type of fund(s) used
Earmarked public budget
Non-financial contribution
Unknown
Business models
Risk reduction model
Which of the involved actors was motivated by this model?
Public actor (e.g. municipality)
Type of innovation
Unknown
Novelty level of the innovation
Unknown
Please specify novelty level of the innovation
Renaturalization is a common procedure that has been applied for decades. I would therefore consider the level of innovation to be low.
Replicability/Transferability
Unknown
Please specify Replicability/Transferability
Expanding the renaturalization measures to areas further downstream are planned (Ref. 2)
Impacts, benefits
Environmental impacts
Climate change
Strengthened capacity to address climate hazards/natural disasters
Water management and blue areas
Improved water quality
Increased protection against flooding
Enhanced protection and restoration of freshwater ecosystems
Description of environmental benefits
- With the re-naturalization and expansion of the Rheinstream and the flood retention area of the stream itself and also the Rhein, the areas are better prepared for the anticipated effects of climate change (2).
- The biological water quality of the stream has improved due to the new natural riverbed that is an ideal habitat for microorganisms, the natural floodplain area, available deadwood and the natural flow conditions. According to a study the environmental quality of the renaturalized stream section is higher compared to then non-renaturalized parts, in terms of water quality, species diversity and soil quality. The study classified the water quality of the restored stream section "good" sometimes "very good" (6).
- With the restoration of the natural curvy and wider course of the stream, its retention capacity has been increased and its total length has been extended that both contribute to lowering the risk of flooding. The expansion of the natural flood plain also adds to the flood risk reduction efforts. (2)
- With the removal of the concrete bed of the stream and the re-greening of the area with native floodplain plants, the natural biodiversity of the stream has been restored that resulted in the advanced development of microorganisms and habitat creation ideal for native plant and animal species of the floodplain (2,6).
Economic impacts
Unknown
Description of economic benefits
Unknown
Social and cultural impacts
Health and wellbeing
Gain in activities for recreation and exercise
Description of social and cultural benefits
- With benches and natural design the riverbank area of the Rheindorfer stream is ideal for recreational activities. (1,6)
Type of reported impacts
Expected impacts
Achieved impacts
Indicators
- Length of the stream (1,2,6);
- Capacity of the flood retention area in cubic meters (2);
- Biological water quality (6).
Environmental, social and economic impacts
Climate action for adaptation, resilience and mitigation (SDG 13)
Environmental quality
Green space, habitats and biodiversity (SDG 15)
Water management (SDG 6)
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
No evidence in public records
Methods used to evaluate the impacts of NBS
Unknown
Evidence for use of assessment
Presence of an assessment, evaluation and/or monitoring process
No
Presence of indicators used in reporting
No
Presence of monitoring/evaluation reports
No
Availability of a web-based monitoring tool
No
Impact assessment mechanism
Name of any specific impact assessment tools
No impact assessment tools have been used. However, independently to the project, a study on the environmental quality of the river has been performed in 2017 which compared two different river sites (one where the naturalization occurred and another further upstream with heavily modified, artificial water body) and found that they differ in their ecological condition. The one in the renaturalized area turned out to score better in several assessment categories (hydro-morphological, chemical, biological) (6).
Link to the output of assessments
http://www.ewa.uni-bonn.de/e.wa/eWaComponents/Literature/3_eWaJournal/pdf/e.Wa_…
Use of GIS in mapping impacts
No
Citizen involvement
Citizens involvement in assessment/evaluation
No
Citizens involvement in the analysis of the assessment/evaluation
No
Follow-up to the evaluation / assessment
No
References
Web links relevant to the intervention
short description of the project (absence of website)
Article in General-Anzeiger Bonn
Article in Kölner Stadt-Anzeiger
List of references
1. City Council for Urban Development (2002) ‘Die Umgestaltung des Rheindorfer Baches in Auerberg und Graurheindorf’. Bonn: City Council of Bonn, p. 2. Document unavailable on September 11, 2020
2. Kleinfeld, R. (2002) ‘Aus einem Beton-Bach wird eine Auenlandschaft’, General-Anzeiger Bonn. Accessed on September 11, 2020 http://www.general-anzeiger-bonn.de/region/Aus-einem-Beton-Bach-wird-eine-Auenlandschaft-article157640.html.
3. Johnen, R. (2002) ‘Zurück zur Natur - stückweise’, Kölner Stadtanzeiger, 19 August. Accessed on September 11, 2020 http://www.ksta.de/zurueck-zur-natur---stueckweise-14150568.
4. Tiefbauamt Bonn (2008) ‘Bachentwicklungsplan 2008. Überarbeitung und Fortschreibung des BEP 1988’. Bonn: City Council Bonn, p. 108. Accessed on September 11, 2020. http://atlas.naturvation.eu/sites/default/files/nbs/reports/bachentwicklungsplan_2008fortschreibung.pdf
5. Stadtbauamt Bonn Kanal-und Wasserbauabteilung (1997) ‘Hochwasserschutz - Konzept’. Bonn: City Council Bonn, p. 82. Accessed on September 11, 2020. http://atlas.naturvation.eu/sites/default/files/nbs/reports/1997-12-xx-dok_hochwasserschutzkonzept_bonn.pdf
6. Baum, M. and Claren, J. (2017) ‘Gewässerökologische und ökosystemare Untersuchung des Rheindorfer Bachs in Bonn’, Zeitschrift für wasserbezogene Forschung von Studierenden, 1 (Wasser im urbanen Raum. Eine sozio-hydrologische Betrachtung), pp. 42–50. Accessed on September 11, 2020. http://www.ewa.uni-bonn.de/e.wa/eWaComponents/Literature/3_eWaJournal/pdf/e.Wa_Journal_2017vol.1.pdf.
Attachments
Attachment Size
Policy document "Bachentwicklungsplan" 2008 revision (1.65 MB) 1.65 MB
Policy document "Hochwasserschutzkonzept" 1997 (1.69 MB) 1.69 MB
Project folder renaturalizing the Rheindorfer stream (789.63 KB) 789.63 KB
Scientific journal assessment environmental quality of the stream (3.87 MB) 3.87 MB
Comments and notes
Public Images
Renaturalization of the Rheindorfer Stream (From Matthias Franke 2006)
Renaturalization of the Rheindorfer Stream (2006)
Matthias Franke, retrieved 07/19/2018
Renaturalization of the Rheindorfer Stream
Renaturalization of the Rheindorfer Stream (2006)
Matthias Franke, retrieved 07/19/2018
Renaturalization of the Rheindorfer Stream
Renaturalization of the Rheindorfer Stream (2006)
Matthias Franke, retrieved 07/19/2018