Participative evaluation of Sustainable Urban Drainage systems with ClimateCafé Malmö

Malmö is well known within the field of urban hydrology, as the city was a pioneer in integrated water management (Stahre 2008). In 1998 the Augustenborg neighbourhood was refurbished due to its reoccurring problems with flooding and damage caused by water (Niemczynowicz 1999). The project “Ekostaden” (Eco-city) included many initiatives implementing nature-based solutions (NBS), such as swales and rain gardens for infiltrating surface (storm) water into the ground (Climate Adapt 2016) (Figure 1). International stakeholders want to know if these NBS still function satisfactorily after 20 years and what we can learn from the “Augustenborg strategy” and apply in other parts of the world. To quote the German philosopher Georg Wilhelm Friedrich Hegel, “we learn from history that we do not learn from history.” Augustenborg is an ideal location to demonstrate the sustainability of NBS, test the functionality for infiltration of surface water in swales, map the build-up of potential toxic elements (PTE), and test the water quality after 20 years operation. This evaluation is done in 2019 with the international, participatory and multidisciplinary method ‘ClimateCafé and the results are presented at the international seminar Cities, rain and risk, June 2019 in Malmö (Boogaard et al. 2019). ClimateCafé is a field education concept involving different fields of science and practice for capacity building in climate change adaptation. Over 20 ClimateCafés have already been carried out around the globe (Africa, Asia, Europe), where different tools and methods have been demonstrated to evaluate climate adaptation. The 25th edition of ClimateCafé took place in Malmö, Sweden, in June 2019 and focussed on the Eco-city of Augustenborg. The main research question - “Are the NBS in Augustenborg still functioning satisfactorily?”- was answered by interviews, collecting data of water quality, pollution, NBS and heat stress mapping, and measuring infiltration rates (Boogaard et al. 2020)

Potential Toxic Elements in Sustainable Urban Drainage Systems:Is the Soil Quality of Bio-Swales after 10–20 Years Still Acceptable?

Sustainable urban drainage systems (SuDS) or nature-based solutions (NBSs) are widely implemented to collect, store and infiltrate stormwater. The buildup of pollutants is expected in NBSs, and Dutch guidelines advise monitoring the topsoil of bio-swales every 5 years. In the Netherlands, almost every municipality has implemented bio-swales. Some municipalities have over 300 bio-swales, and monitoring all their NBSs is challenging due to cost and capacity. In this study, 20 locations where bio-swales with ages ranging between 10 and 20 years old were selected for a field investigation to answer the following question: is the soil quality of bio-swales after 10 years still acceptable? Portable XRF instruments were used to detect potential toxic elements (PTEs) for in situ measurements. The results showed that for copper (Cu), zinc (Zn) and lead (Pb), 30%, 40% and 25% of the locations show values above the threshold and 5%, 20% and 0% above the intervention threshold, meaning immediate action should be taken. The results are of importance for stakeholders in (inter)national cities that implement, maintain, and monitor NBS. Knowledge of stormwater and soil quality related to long-term health risks from NBS enables urban planners to implement the mostappropriate stormwater management strategies. With these research results, the Dutch guidelines for design, construction, and maintenance can be updated, and stakeholders are reminded that the monitoring of green infrastructure should be planned and executed every 5 years

Knowledge exchange on climate adaptation best management practices for sustainable water management in resilient cities

Cities are becoming increasingly vulnerable to climate change, and there is an urgent need to make them more resilient. The Climatescan adaptation tool www.climatescan.nl is applied as an interactive tool for knowledge exchange and raising awareness on Nature-Bases Solutions (NBS) targeting young professionals in ClimateCafes. Climatescan is a citizen science tool created through ‘learning by doing’, which is interactive, open source, and provide more detailed information on Best Management Practices (BMPs) as: exact location, website links, free photo and film material. BMPs related to Innovations for Climatic Events (INXCES) as stormwater infiltration by swales, raingardens, water squares, green roofs subsurface infiltration are mapped and published on social media. Climatescan is in continuous development as more data is uploaded by over 250 people around the world, and improvements are made to respond to feedback from users. In an early stage of the international knowledge exchange tool Climatescan, the tool was evaluated by semi-structured interviews in the Climatescan community with the following result: stakeholders demand tools that are interactive, open source, and provide more detailed information (location, free photo and film material). In 2016 Climatescan (first stage of INXCES) was turned into an APP and within two years the tool had over 10,000 users and more than 3,000 international projects. More than 60% of the users are younger than 34 and 51% of users are female, resulting in engagement with an important target group: young professionals. The tool is applied in Climatecafe.nl around the world (The Netherlands, Sweden, Philippines, Indonesia, South Africa) where in a short period of time stakeholders in triple helix context (academia, public and private sector) work on climate related challenges and exchange their knowledge in a café setting. Climatescan has also been used in other water challenges with young professionals such as the Hanseatic Water City Challenge and Wetskills. During the INXCES project over 1000 BMPs related to Innovations for Climatic Events (INXCES) are mapped in all partner countries (figure 1). The points of interest vary from just a location with a short description to a full uploaded project with location, description and summary, photos and videos, presentations, links to websites with more information and scientific papers and books (as Bryggen in Norway: https://www.climatescan.nl/projects/16/detail )

Risk assessment for areas prone to flooding and subsidence:a case study from Bergen, Western Norway

Bergen city centre is prone to both subsidence and flooding. With a predicted increase in precipitation due to climate change, a higher proportion of rainfall becomes surface runoff, which results in increased peak flood discharges. In addition, it has been predicted that sea-level rise and increasing storm surges will result in coastal flooding. In this study, the dual hazards of flooding and subsidence are analysed to exemplify possible risk assessment maps for areas most prone to the combination of both. Risk assessment maps are a support tool to identify areas where mitigation of subsidence and adaptation for surface water management will be most efficient and measures can be implemented. The results show that dual hazard assessment, like that described in this paper, can be a useful tool for decision-makers when prioritizing areas to implement measures such as Sustainable Urban Drainage Systems

ClimateCafé: an interdisciplinary educational tool for sustainable climate adaptation and lessons learned

ClimateCafé is a field education concept involving dierent fields of science and practice for capacity building in climate change adaptation. This concept is applied on the eco-city of Augustenborg in Malmö, Sweden, where Nature-Based Solutions (NBS) were implemented in 1998. ClimateCafé Malmö evaluated these NBS with 20 young professionals from nine nationalities and seven disciplines with a variety of practical tools. In two days, 175 NBS were mapped and categorised in Malmö. Results show that the selected green infrastructure have a satisfactory infiltration capacity and low values of potential toxic element pollutants after 20 years in operation. The question “Is capacity building achieved by interdisciplinary field experience related to climate change adaptation?” was answered by interviews, collecting data of water quality, pollution, NBS and heat stress mapping, and measuring infiltration rates, followed by discussion. The interdisciplinary workshops with practical tools provide a tangible value to the participants and are needed to advance sustainability eorts. Long term lessons learnt from Augustenborg will help stormwater managers within planning of NBS. Lessons learned from this ClimateCafé will improve capacity building on climate change adaptation in the future. This paper oers a method and results to prove the German philosopher Friedrich Hegel wrong when he opined that “we learn from history that we do not learn from history