Marianne Beckmann
Marianne Beckmann, head of the Network division at VA Syd (formerly VA-verket Malmö). Has worked on stormwater issues for 20 years in Malmö and has led many tours of the Augustenborg stormwater system.
leap together and improve the environment in Au-gustenborg.
The Eco-city Augustenborg project aimed to increase the area’s sustainable development, be it economic, social or environmental. VA-verket saw an opportunity to further develop its plans for sus-tainable stormwater management.
Throughout the 1990s, VA-verket had built several blue-green infrastructures, mainly in new developments in Malmö’s outskirts. This had been part of the inter-departmental cooperation that had been implemented around the detailed planning process. It had also introduced methods to slow the flow of water in built-up areas, such building a pond at Olof Hågensens Allé and a swale along Vanåsgatan. Here engineers managed to reduce the risk of basement flooding by superfi-cially slowing the rainwater’s path.
In Augustenborg, several departments got in-volved and the ambitions were considerably loft-ier. In their hands they had a unique opportunity to apply the principles of sustainable stormwater management to a whole district’s built environ-ment. Compared with the efforts at Olof Hågen- sens Allé and along Vanåsgatan, where no major changes were made beyond the streets themselves, Augustenborg offered new opportunities to test ideas on a larger scale and tie many components into a whole. Augustenborg sits on the border be-tween the dense inner city and sparser residential areas, so the new systems would be more urban than those in newly developed areas on Malmö’s outskirts.
Augustenborg’s sewage system was built ac-cording to the standards of the 1950s. It was a combined system, which collects stormwater and wastewater through the same pipes. The down-side to this is that during heavy rain the system can overload. risking an outflow of wastewater in nearby basements connected to the system. In Augustenborg, flooded basements were a common problem, and there was a huge need to relieve the sewage system. Traditional solutions could have
been used, but those responsible instead chose to try new ideas and methods for sustainable storm-water management.
The way the area was built, with open court-yards and “houses in the park”, was well suited for a new way of diverting stormwater above ground.
Although the area’s flatness was a clear challenge.
From conventional to experimental
Several initiatives in the Eco-city project involved stormwater management. The theoretical part of transforming the system was a project called Open stormwater management in a built-up district, which was funded by MKB, the Streets and Parks Department, the Internal Services Department, the VA-verket water utility, Byggforskningsrådet (now Formas) and VA-forsk (now Svenskt Vatten Utveckling). The application to Byggforsknings-rådet (the Building Research Council) lists three challenges that the project is designed to overcome:
1. Environmental stormwater management - to manage stormwater locally as far as possible.
Augustenborg’s rainwater would be diverted away from the combined sewage system to re-duce the risk of basement flooding. The next step was to separate the pipe network outside the area, so that the stormwater that needed to be diverted, despite the open system, would not be routed to pumping stations and sew-age treatment plants, but instead led directly to the recipient which is Malmö’s canals.
2. To foster increased social and environmental sustainability by creating an interesting and varied urban environment where stormwater is given space and through design can con-tribute to well-being for the residents and in-creased biodiversity.
3. To develop the sub-components of the storm-water system so they can later be implement-ed in other more densely populatimplement-ed parts of the city, but also newly developed areas.
Augustenborg was to be a national and inter-national inspiration.
Stormwater would be locally managed by de-laying the raindrops’ journey through the city’s landscape. For this, the builders laid green roofs, and installed gutters, canals and delay ponds at ground level. Work was planned for areas owned by the Internal Services Department (the engi-neering unit’s workshops were covered in green roofs and a botanical roof garden was created), in MKB’s residential gardens, in the schoolyard and in the park. Two new open waterways would also
be built, one in the south and one in the north.
There was an agreement to see the opportunities rather than limitations. The conventional ap-proach, which accounts for property boundaries and connection points, would be thrown out during the expansion and the work would focus on shared solutions. Throughout the Eco-city Au-gustenborg project holding a dialogue with resi-dents was vital (Stahre, 2008).
The stormwater system was changed in stages.
It started in the southern part of Augustenborg, where water flows east to west before being divert-ed into stormwater pipes in the southwestern part of Augustenborg and taken to Malmö’s canals. See Image 1.
In stage one, ambitions were very high, in both design and capacity terms. Those responsible wanted to preserve (and to some extent recreate) the area’s period character, which is also clear in the design of the stormwater system, which followed a rather strict form. The overarching vision was of a water system which was visible throughout, from
Image 2. The drainpipe and gutter in stage 1, southern section. Image by Lars-Erik Widarsson and Ulf Thysell.
the bottom of drainpipes to open gutters and ca-nals. Rainwater would come off roofs and follow the drainpipes into open gutters, which created a difference in level in the pavement, see Image 2.
The gutters run to a concrete canal, see Image 3. The canal was designed to mimic the 1950s design that was to be recreated and was large
enough detain a so-called 25-year rainfall event, of the type that happens on only one day in each quarter century.
The journey continues through a wet pond, which slows the water’s path, to another canal, with concrete cubes along the bottom, see Image 4. The cubes symbolise a stylised stream. The ca-nal’s irregular bottom creates vortices which help oxygenate the water, while vegetation could be es-tablished on the bottom (Stahre, 2008). The water then flows into a meandering swale before being collected and delayed in a pond at the southwest corner of the district. Here, there is also an outlet connected to pipes in the adjoining street.
When the southern section was completed, stage two - the northern section – began, see Fig-ure 6. The section runs along Lönngatan and in the northwest ties into the drainage pipe network outside the area. By the time planning and imple-mentation started, parts of the original manage-ment team had been replaced and the objective had in part changed (Delshammar et al, 2004).
The capacity was reduced to only manage a so-called 10-year rainfall event - while the designers abandoned the austere 1950s look and integrated the open waterways more into natural appearance,
Image 5. At the end of the system a large pond slows the water’s journey. An overflow mechanism that leads into the pipe network in the street beyond is visible at the far end of the pond. The picture was taken in 2016 shortly after the surrounding vegetation was cleared and cut down. Image by Stefan Billqvist.
Image 1. Stage one, southern section. Illustration by ISS Landsca-ping (from presentation by Joanna Theland).
Image 4. “The cube canal”. Image by Elisabet Rudenholm.
Image 3. The ‘50s-style concrete canal. When the picture was taken in 2002, railings had not yet been installed at the canal crossings. Image by John Dolocek.
see Image 7. This was probably a combination of wanting to reduce costs, while thinking a grassy swale was more appealing than a concrete canal.
In the same way, roof runoff was “hidden” in the northern section, as the drainpipes were di-rected straight into the ground, and connected to nearby swales, see Image 9. Just as with the latticed gutters, you must look closer to understand how the stormwater is handled. It looks like a conven-tional system but is still a surface system with large capacity. In this stage, less focus was placed on in-cluding residents, but instead MKB did more in the gardens than during the first stage, which were also upgraded to handle stormwater at surface level (Delshammar et al, 2004).
Alongside the construction of the new storm-water system in Augustenborg, the network of pipes outside Augustenborg was redesigned to lead stormwater from the district into Malmö’s canals, meaning it no longer put strain on downstream pumping stations and sewage treatment plants.
The last stage in the transformation of the stormwater system involved laying a new pipeline along Augustenborgsgatan. Conventional pipes under the street were the preferred option here due to the topographical challenges of the area, but the outcome was exactly the same as in the open system. The pipes diverted the rainwater away from the sewage system. That way rainwater does not end up putting strain on Malmö’s pumping stations and treatment plants, but instead runs harmlessly into the city’s canals.
Image 7. Stormwater swale along Lönngatan. Image by Ulf Thy-sell. The gutters here were given lattice covers, rather than being open, making the stormwater system less visible in the urban environment, see Image 8.
Image 8. During stage two, which developed the northern section, the open gutters were replaced by latticed gutters, and the gravel with asphalt. Image by Ulf Thysell
Image 9. In stage two, the northern section, it is less obvious that the drainpipe deposits its water above ground. Image by Ulf Thysell.
Image 6. The northern section. Illustration by ISS Landscaping (from a presentation by Joanna Theland)
Foto: Leif Runeson.
Image 10. The pond at Södra Grängesbergsgatan. A. Newly built pond 2002, image by John Dolocek.
B. The pond a year later, image by Ulf Thysell. C. Redesigned pond in 2012 which had the same holding capacity but was differently designed and had a pump to circulate the water, image by Leif Runeson.
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Lessons learned
The Augustenborg project was characterised by a willingness to try new ideas and push boundaries.
Through the residential area, in gardens, a new ca-nal system led water from the drainpipes through gutters. Playgrounds and green areas in the resi-dential gardens were designed to handle and retain stormwater. A stormwater swale was built along a cycle path. It was a full-scale experimental work-shop, where boundaries and regulations were no restraint and test first and adapt later was the guid-ing principle.
The result is an area which is globally renowned among stormwater enthusiasts, and still today at-tracts visitors from near and far to explore how a sustainable urban drainage system can be integrat-ed into a semi-urban residential environment. But of course, the experimental spirit has meant some parts are adapted over time, as they have been dis-covered to work less well. Among these were some accessibility angles that were not considered at first when the focus was on creating an innovative stormwater system. These have subsequently been remedied (Niemi et al, 2004).
One reason the Augustenborg project started in the first place was the clear commitment to the stormwater issue from several players in the mu-nicipality, who shared an ambition to try some-thing new, exciting and better. Augustenborg was ripe for change, as property owner MKB wanted to increase the area’s status, water utility VA-verket had new ideas about sustainable stormwater man-agement which suited MKB, while the Service Department was as interested in investing in its properties. There was an enormous desire to try something new, to take the issue of open and sus-tainable stormwater management one step further, and this made it possible to focus on the possibili-ties instead of being limited by obstacles.
Now that twenty years have passed, parts of the stormwater system have changed, after the limit-less and permissive culture also brought problems that were discovered during operations. A change that was made rapidly was the design of the pond
by Södra Grängesbergsgatan. In its original form, algae started to grow as nutrients entered the wa-ter stream, which was also poorly oxygenated, see Images 10a and b. The pond was remade, while maintaining inertia in the system and not chang-ing the amount of floodchang-ing it could deal with. A circulation pump was installed to combat algae formation and make the outdoor environment more pleasant, see Image 10c. Fresh water is pumped into the system by MKB for aesthetic reasons at times of low rainfall (Eliasson 2018).
Making the stormwater’s route from the roofs across the area visible, a feature that had been so important during stage one in the south, had al-ready disappeared when the northern section of the system was built. Over time the appearance of stage one has also changed as the original drain-pipes and gutters have been replaced by drains that are connected to latticed gutters which do not cre-ate an indentation, a little bump, in the ground.
Maybe this is because it increases accessibility and decreases operating costs.
The management of the blue-green infrastruc-ture has sparked discussions and changes. From the beginning, the operations were meant to fol-low the spirit of the Eco-city: a group of local res-idents would be hired to care for the stormwater system in their neighbourhood. However, this never came to fruition (Söderblom, 2004). The stormwater system is currently managed by a con-tractor hired by the Property Management, Street and Parks Department, but paid for by VA Syd.
There is still some uncertainty about which areas MKB is responsible for, and which fall to VA Syd (Eliasson, 2018). See more on experiences from managing the system on page 193.
In stage one in particular, the southern section, a lot of time was spent engaging with residents.
At the same time, time was limited and the pro-ject was complex. The amount of influence that residents could really have was therefore very lim-ited (Delshammar et al, 2004). In addition, the meetings were not very well attended, making it doubtful how much they represented the views
of the community at large (Krantz et al, 2002).
In general, communicating with customers and residents is significantly more prioritised today than it was 20 years ago, and there would have been a different level of communication and con-versation if a similar project was carried out today.
How do we proceed?
As noted earlier, Augustenborg’s outdoor environ-ment became a kind of experienviron-mental workshop be-cause four players were willing to work together to solve the stormwater problems, and push bound-aries together.
Since Augustenborg’s stormwater system was rebuilt, Malmö has faced several heavy rainfall events, which the system has clearly handled well.
This demonstrates how much capacity is provid-ed by a system that slows the water and directs it to controlled flooding areas. It is therefore part of ensuring Malmö can withstand heavy downpours.
The lessons from Augustenborg, and from other ar-eas with sustainable urban drainage systems, have therefore been considered in subsequent projects to plan and manage rainfall. There is a clear awareness that several municipal departments and the water utility need to work together to develop sustaina-ble stormwater solutions in a built-up urban area.
Together we must make room for the water. How-ever, most other districts have many more property owners and other stakeholders than Augustenborg, which makes it difficult to copy the area’s storm- water system directly.
Although the quality of stormwater was consid-ered when building the open system through Au-gustenborg, the project almost exclusively focused on managing heavy downpours. Today, quality is much more at the centre. This is in part because of the EU Water Directive and environmental qual-ity standards and, above all, the higher standards of stormwater quality that will be demanded going forward. The solutions in Augustenborg are clearly part of how to manage stormwater, but improve-ments must still be made.
The transformation of Augustenborg’s stormwa-ter system is still unique and may continue to be so going forward. It was a special initiative which was allowed to challenge engineering, design and finan-cial norms. The experience from both the project’s successes and the parts that need improvement has informed VA Syd’s later work. The schematic pic-ture that Peter Stahre drew to demonstrate the tran-sition from conventional to sustainable stormwater management, see Image 11, is still valid. Stormwa-ter management encompasses both waStormwa-ter quanti-ty and water content, and its aesthetics when it is diverted above ground. But the emphasis must be decided for individual projects, not least amid com-mon discussions on multifunctionality. In a densi-fying urban environment, which is accommodating more and more people, multifunctionality becomes increasingly important. So as not to get lost during operations, the system’s main purpose needs to be clarified. Is it a meeting place, an area designated for stormwater handling or a meadow for pollinat-ing insects? Is the rain garden by the street primarily a stormwater treatment plant, a street decoration or a traffic safety measure?
Image 11. From traditional to sustainable stormwater manage-ment (Stahre 2004).
Quantity
Quality
Quantity Design