Stormwater runoff has severe negative and direct impact on the quality of surface waters and groundwater. The impact can cause chemical and heavy-metal pollution. Applying well established methods to map pollutants in urban areas and specifically in Nature-Based Solutions (NBS), such as Sustainable UrbanDrainage Systems (SuDS) is a step towards improving the water quality in the urban water cycle. Traditional mapping of pollutants by the means of soil samples is costly, which is the main reason why the environmental-technical functioning of rainwater facilities has not been investigated on a large scale andsystematically. X-ray fluorescence (XRF) is a known analysing method for finding metals and other components, for laboratory analysis and portable instruments. In this work we propose a new approach of mapping method for pollutants in-situ, such as heavy metals in soil in SuDS, with case studies from theNetherlands where swales were implemented 20 years ago. In situ XRF measurements is a quick and costefficient analysis for heavy meatal mapping in the respect to contaminated soil. In situ XRF measures of various elements, including heavy metals is carried out in a quickscan and accurate manner and measures both qualitatively and quantitatively. It makes the time-consuming and costly interim analyses by laboratories superfluous. In this study, we suggest a new methodology approach for in situ mapping of pollutants in various swales that were implemented from 20 to 5 years ago. The results differ due to multiple factors (age, use of materials, storage volume, maintenance, run off quality, etc.). Several locations reached unacceptable levels, above the national thresholds for pollutants. The spatial distribution of pollutants in the over 30 swales mapped in the Netherlands show that the preferred water flow in theSuDS controls the spreading of pollutants. The swales investigated are presented in an interactive way with the open source tool www.climatescan.nl, containing more than 100 swales, part of which has been investigated with in situ XRF measurements. The research results are of great importance for all stakeholders in (inter)national cities that are involved in climate adaptation. SuDS is the most widely used method for storing stormwater and infiltrating in the Netherlands. However, there is still too little knowledge about the long-term functioning of the soil of these facilities.
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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.
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In recent years, there has been a steady increase in the number of bioretention systems installed worldwide. However, there has only been limited research on the long-term effectiveness of these sustainable urban drainage system devices. This paper presents the results of a series of controlled field experiments investigating the pollutant removal efficiency of three bio-filtration system that have been in service for over five years in the Sunshine Coast in Australia. The results of this study suggest that the long-term pollution removal performance of these systems may not be as effective as previously thought and further research is needed.
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Sustainable urban drainage systems (SuDS) such as swales are designed to collect, store and infiltrate a large amount of surface runoff water during heavy rainfall. Stormwater is known to transport pollutants, such as particle-bound Potential Toxic Elements (PTE), which are known to often accumulate in the topsoil. A portable XRF instrument (pXRF) is used to provide in situ spatial characterization of soil pollutants, specifically lead (Pb), zink (Zn) and copper (Cu). The method uses pXRF measurements of PTE along profiles with set intervals (1 m) to cover the swale with cross-sections, across the inlet, the deepest point and the outlet. Soil samples are collected, and the In-Situ measurements are verified by the results from laboratory analyses. Stormwater is here shown to be the transporting media for the pollutants, so it is of importance to investigate areas most prone to flooding and infiltration. This quick scan method is time and cost-efficient, easy to execute and the results are comparable to any known (inter)national threshold criteria for polluted soils. The results are of great importance for all stakeholders in cities that are involved in climate adaptation and implementing green infrastructure in urban areas. However, too little is still known about the long-term functioning of the soil-based SuDS facilities.
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The challenge of sustainable development requires cities to aim for drastic improvements in the systems that support its vital functions. Innovating these systems can be extremely hard, and might take lots of time. A transparent and democratic strategy is important to guarantee support for change. Such a process should aim at developing consensus regarding a basic vision to guide the process of systems change. This paper sketches future options for the development of sanitation- and urban drainage systems in industrialized economies. It will provide an analysis of relevant trends for sewage system innovation. In history, sewage systems have emerged from urban sewage and precipitation removal systems, to urban sewage and precipitation removal and cleaning systems. The challenge for the future is recovering energy and resources from sewage systems while maintaining/improving its sanitary service and lowering its emissions. https://doi.org/10.3390/su11051383 LinkedIn: https://www.linkedin.com/in/karel-mulder-163aa96/
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Climate change and urbanization will increase the frequency and magnitude of urban flooding and water quality problems in many regions of the world. In coastal and delta areas like The Netherlands and the Philippines, where urbanization is often high, there has been an increase in the adoption of sustainable urban drainage systems (SUDS). SUDS are installed around the world with the expectation to reduce urban flooding and reduce the pollution impact on receiving waters. Most cities in Asia are starting to implement SUDS as their strategy to make their cities sustainable and resilient.The combination of SUDS with appropriate wastewater treatment and management systems have the potential to be multifunctional in alleviating flood run-off, improving water quality, alleviating heat stress and as a source for reusing the stormwater and wastewater.Since the earliest SUDS are implemented in Europe decades ago it is advised to use the lessons learnt in this process. International knowledge exchange is promoted in projects as IWASTO where several organisations from the Philippines and The Netherlands join forces on a specific region as the Pateros riverin Manila with the aim to minimise the pollution impact on this receiving water. The first findings of this project related to storm water and wastewater management are presented in this paper. In this stage of the project high level support models that map the challenges in the city (such as flooding and heatstress) arevaluable tools for implementing cost effective sustainable drainage for improving water quality.
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One of the goals for the JPI Water funded project INovations for eXtreme Climatic Events (INXCES) is to provide risk assessment tools for urban hydro-climatic events. Combining disciplines increases the capacity to manage and improve the mitigation of the infrastructure for stormwater in urban areas. INXCES is an European collaboration among the cites Bergen, NO, Groningen, NL, Bucharest, RO, and Luleå, SE.In urban areas infrastructure, such as sewage and drainage systems, is installed in the subsurface to cope with surface water and stormwater runoff. However, the natural patterns are preferred hence human effort. A flood model using Digital Elevation Model (DEM) show the flow patterns of stormwater and areas exposed to flooding. Combining mapping of natural flow paths and floodmodelling, areas prone to flooding is accentuated. The subsurface infrastructure in these prone areas are exposed to larger quantities of water during heavy rainfall events, which is becoming more frequent due to climate change. Results from this interdisciplinary study, will give the water and wastewater authority a risk assessment to pinpoint areas where water infrastructure is more exposedto failure, clogging and damages. Furthermore, we argue that areas that are prone to repeated flooding are more exposed for subsidence in the ground. Larger movement in the ground will cause damage to the infrastructure, such ascracking of pipelines and damage to buildings, roads etc. By combining results mentioned above with subsidence data (InSAR date collected from Satellites), a risk assessment map can show areas to prioritize. Subsurface measures such as SUDS (Sustainable Urban Drainage Systems) can be a resilient solution to a recurrent problem in an urban area, as a remediation to flooding (and drought)and as stabilisation of ground conditions.
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A baseline study was performed to characterize the stormwater quality from the upstream roofs and road areas. Results showed variations in stormwater quality. This may inhibit single-step treatment performance. Therefore, a ‘treatment train’ of several SUDS measures was developed in order to achieve high pollutionremoval rates and to help prevent loss of valuable archaeological deposits and thereby reduce subsidence.
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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 anddamage 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 demonstratethe 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 theinternational, 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 carriedout 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).
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The shallow subsurface in historic cities often contains extensive archaeological remains, also known as cultural deposits. Preservation conditions for naturally degradable archaeological remains are strongly dependent on the presence or absence of groundwater. One of the main goals at such heritage sites is to establish a stable hydrological environment. Green infrastructural solutions such as Sustainable Urban Drainage Systems (SUDS) can support preservation of cultural deposits. Several cases show that implementation of SUDS can be cost effective at preservation of cultural deposits. These include Motte of Montferland, City mound of Vlaardingen, Weiwerd in Delfzijl, and the Leidse Rijn area. In all cases, the amount of underground infrastructure is minimised to prevent damaging cultural layers. SUDS have been implemented to preserve cultural heritage. The first monitoring results and evaluation of the processes give valuable lessons learned, transnational knowledge exchange is an important element to bring the experiences across boundaries.
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