Techniques, materials and processes for construction and design
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NEW EUROPEAN BAUHAUS AWARDS : existing completed examples
Blue Green Grey Systems
Full project title
Blue Green Grey Systems for reslilient and livable streetscapes
Our complex urban environments require flexible designs that can handle multiple functions simultaneously and make their surrounding flourish. Blue Green Grey System is nature-based technology for designing multifunctional spaces where elements like Blue (water) Green (vegetation) and Grey (hard surfaces) are integrated in the same area and volume. The result is a more beautiful, healthy and climate-resilient urban environment that is better prepared for future challenges.
Where was your project implemented in the EU?
When was your project implemented?
Has your project benefited from EU programmes or funds?
Which programme(s) or fund(s)? Provide the name of the programme(s)/fund(s), the strand/action line as relevant and the year.
II. DESCRIPTION OF THE PROJECT
Please provide a summary of your project
Our complex urban environment requires flexible designs that can handle multiple functions simultaneously and make their surrounding flourish with lower demands for space and lower expenses for building and maintenance. By integrating Blue, Green and Grey systems (BGG systems) we create multifunctional streetscapes that can handle transport and traffic load (the grey), stormwater and pollution (the blue) and at the same time give the vegetation's rootsystem the space it needs to thrive (the green). The result is a more attractive and resilient urban environment with lower risk of flooding and reduced drought stress to vegetation that can deliver its ecosystem services.
Hard surfaces such as roads, parking lots, walkways and cycle paths are traditionally constructed with a subbase layer that consists of crushed rock with the fraction 0-90 mm. In this conventional subbase the roots struggle to grow due to very low permeability and gas exchange and there are no possibilities to use the subbase for storage of stormwater. In BGG-system, the subbase is utilized in a new way. By using crushed rock without the fine fractions (open subbase material) there will be a subbase with large pores that can be filled with water and air. The Open Subbase Layer (OSL) has a capacity to detain up to 400 l of water per cubic meter. Using the OSL as a foundation for the system, we then add other facilities to the design. Depending on the use of the space, the demands of stormwater management for the specific site and on desired design, we install different constructions for example rain gardens, plant beds, permeable pavement, tree trench etc.
The system was originally developed in the Swedish innovation project ”Klimatsäkrade systemlösningar för urbana ytor” financed by Vinnova and was first implemented in the new smart district Rosendal in Uppsala in 2019. Building on its success the system is now being implemented in different parts of Sweden and other EU countries.
Please give information about the key objectives of your project in terms of sustainability and how these have been met
The natural water cycle has been disturbed within the modern urban environment, where there is heavy competition for a relatively small amount of space. Previously, trees had the space to extend their roots so that water could seep to them through the ground, but decades of urban construction have created dense superstructures above impermeable surfaces. This kind of environment lacks both adequate space for planting as well as natural water management.
Disregarding circumstances which are crucial for vegetation and stormwater management during city planning causes a number of costly problems. High water flows and floods alternate with damage from drought. Roots destroy construction as they seek better growing conditions. Continued expansion and densification of cities cause an increase of stormwater and the need to replace existing pipes. Climate change and increased demand for both water purification, and better overflow management are also consequences of increased density.
To address the complexities of cities, urban environments require smart infrastructure that can address multiple issues at the same time. Building separate solutions for each function becomes costly and space-consuming. Instead, stormwater management and planting beds can coexist with hard surfaces and their intrinsic requirements for traffic loads and a safe environment. In this way a greener, more attractive urban environment is created which lowers the risk of flooding and damage from drought.
BGG systems contribute to better stormwater
• Regulating stormwater flows, reducing flood risk, purifying water
BGG systems improve conditions for
• Creating large volumes for planting beds, Enabling gas exchange in planting beds, Increasing water access
BGG systems additionally:
• Create aesthetically pleasing and appealing
streetscapes, Lower temperatures of urban streets, Function as a carbon sink, Contribute to circularity by reuse of material from demolition
Please give information about the key objectives of your project in terms of aesthetics and quality of experience beyond functionality and how these have been met
BGG projects can be built with natural elements that are designed for public use and with attention to beauty and aesthetics. It enables the opportunity to upgrade a city’s appearance while at the same time address stormwater management and other important ecosystem services. The combination of blue and green aspects of the infrastructure is especially more beautiful than if these aspects were implemented independently. The places that include the BGG are easier to distinguish because of their correspondence to site topography, native flora and drainage. By providing stormwater functions and function of rootzone underground in form of Open Subbase Layer we create generous and good growing conditions for trees even in extremely dense environments. That will have an effect on growth of tree canopies that can grow in big size which as result has the strong sensorial experience to people who use public spaces. The possibility to work with a wide range of plant material can provide richness of sensorial experience which at the same time compliments increase of biodiversity (see an example from Campus in Vellinge on image bgg_campus.JPG.
Please give information about the key objectives of your project in terms of inclusion and how these have been met
When BGG is well-integrated in the urban space, it increases its safety and acts as a strong motivator for social interaction. It provides with public space where people can engage in recreation and be physically active – alone, in social groups, or with their families. People can use BGG to engage with their own social networks at the same time as they can look and see how others spend their leisure time.
BGG systems has strong benefits for enhancing social interaction and integration, including:
• Increasing activity of people interacting in groups outdoors.
• Increasing people’s predisposition to spending time with family and friends. Therefore, well-integrated BGG has many social benefits, such as inspiring individuals to spend more time with their relatives and friends and proving an aesthetically pleasing space in which to interact.
BGG systems can increase streets' safety for all users of the street and can help to harmonize mobility. That is done for example by:
• placing BGG system with plant beds / rain gardens in a zig-zag form which has an effect on slowing down a car traffic. (see an example of BGG systems on street Rundelsgatan in Vellinge on picture bgg_rundelsgatan_0.jpg)
• placing a stripe of BGG system with rain gardens / plant beds between motorized traffic and cyclpath with sidewalk where plant beds / raingardens act as aesthetically pleasing buffer (see an example of BGG system at Strandbogatan in Uppsala on picture bgg_strandbogatan_0.JPG)
Please give information on the results/impacts achieved by your project in relation to the category you apply for
IMPACT ON CARBON DIOXIDE REDUCTION WITH BIOCHAR
In a BGG System carbon dioxide can be stored as biochar at a possible amount of 135-300 ton CO2e/ha.
IMPACT ON WATER FLOW
Stormwater flow is slowed by raingardens but is also safeguarded by flow regulators in control pits. This results in a stormwater outflow is 5-30 l/s/ha (including climate factor 1.25).
IMPACT ON RETENTION
The system is dimensioned for at least a 30-year rainfall (including climate factor 1.25). The system can retain 40-100 mm of precipitation from the street including front yards and 50% of roof runoff from nearby properties.
IMPACT ON POLLUTION LOAD
BGG systems purifywater with the help of biochar, plant roots, microbiotic life, filtration and sedimentation, they are expected to make a purification level of 70-80%.
IMPACT ON CIRCULAR ECONOMY
BGG systems contribute not only to resume the water cycle but can have an impact on the circulation of materials that were previously used for construction and now are being demolished. During construction of BGG systems can be used reused-concrete (for example from the demolition of buildings) or selected fractions of stones from the subbase layer during the reconstruction of existing streets can be reused as well.
IMPACT ON BIODIVERSITY
Integrating more vegetation and plant varieties in our urban environments improves the opportunities for microorganisms, plants, and animals to survive and flourish. Green corridors between green areas further improve circumstances.
IMPACT ON HEAT AND ENERGY
Vegetation which creates a tree canopy over urban streets helps to keep temperatures from rarely exceeding 25°C by casting shadows and the evaporation effect. Both reduced outdoor temperatures and the shading of facades reduces the need for interior air conditioning, thereby reducing energy consumption.
Please explain the way citizens benefiting from or affected by the project and civil society have been involved in the project and what has been the impact of this involvement on the project
In densely-urbanised areas, people are lacking sensual and spiritual connection with nature. This can have a negative cumulative effect in the form of weak physical and mental health. The BGG provides natural spaces, which support both active and passive recreation, help to provide relief from work and stress and also decrease the prevalence of lifestyle-related diseases, including hypertension, diabetes and obesity. BGG helps urbanites feel more connected to nature and other people – emotionally and intellectually.
Please highlight the innovative character of the project
One of first thoughts during innovation process was if we can find some sort of material or volume that exists everywhere in our streetscapes. We have identified that there exists such space and material that we have in subbase layer, which is the lowest part of superstructure for hard surfaces that consists of crushed rock usually with the fraction 0-90 mm. In this conventional subbase the roots struggle to grow due to very low permeability and gas exchange and there are no possibilities to use the subbase for storage of stormwater.
But we have other superstructures in our cities that can provide stormwater function and even vegetation can grow there sometimes more then we want - like constructions for railway infrastructure where macadam is used. So we raised question. Is something here that we can learn and take it with us? Yes! It is that in such kind of construction we don’t have any zero fraction and that allows for presence of pores! So then we looked again on streetscape and we tried to take away the smallest fractions from the subbase layer and result is that we have very open material with 30-40 % of porosity which allows for retention of stomwater between 300-400 l / m3. The same space we can utilise as rootzone for trees while preserving the function of traffic load. So instead of convention subbase layer we use Open Subbase Layer. It mainly consists of macadam and it works as basis for the BGG system where we can put other constructions like rain gardens, plant beds, parking spaces, etc. on top of it - base on how we want to design our streetcapes.
What is truly unique with this system is that it provides with gas exchange and smart regulation of stormwater. Its multifunctional and flexible which makes it very convenient to include it in standard building processes as we know it.
Please explain how the project led to results or learnings which could be transferred to other interested parties
Together with nine Swedish municipalities, Edge has developed a manual that describes every step to create streetscapes with Blue Green Grey systems. The handbook is addressed at those who plan, design, build, and manage streetscapes and requires guidance in integration of Blue (water), Green (vegetation) and Grey (hard surfaces). Is a supportive and resourceful document that helps to safe-guard complete process of successful implementation of BGG systems – from first investigation steps to design, construction and maintenance so that it can deliver all of its benefits.
The manual is free to download on https://bluegreengrey.edges.se both in English and Swedish.
Edge that is driving the development of BGG systems spents every year approximately 300 hours lecturing about #bluegreengrey systems to municipalities, universities, NGO's and private experts.
Is an evaluation report or any relevant independent evaluation source available?
III. UPLOAD PICTURES
By ticking this box, you declare that all the information provided in this form is factually correct, that the proposed project has not been proposed for the Awards more than once under the same category and that it has not been subject to any type of investigation, which could lead to a financial correction because of irregularities or fraud.
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