This project is established on the following questions:  How can Stockholm adapt to increasing extreme rainfall events through combined stormwater drainage strategies?How can social sustainability be implemented in stormwater treatment?How can stormwater and social design educate the public about the importance of clean water bodies?  Global and national trends show that annual precipitation is increasing, and extreme weather events are becoming more common. Urban landscapes are more susceptible to cloudburst flooding due to impervious surfaces. Additionally, when the stormwater runoff reaches water bodies, it can pollute its recipients unless the stormwater is treated beforehand. Stockholm is an urbanised area with several surrounding water bodies of various sizes that are burdened by human activity, and the water quality in most water bodies is currently at an unsatisfactory ecological and chemical level.  The project site has been determined through mapping, where the accumulation of stormwater flows have been mainly considered. Another important factor is the socio-economically vulnerable aspect, to be able to tackle the social sustainability aspect. For this project, the lake Magelungen is the water body targeted, and the connected site is Hagsätra. This project is using a holistic approach to stormwater management, where the design of recreational spaces, such as parks and playgrounds, can be utilised to serve an ecological as well as a social purpose. A set of toolboxes have been set forth through research and case studies which have been contextualised in the site through sequences and strategies.

Many municipalities have established stormwater user fees (SUFs), commonly known as stormwater utilities, to raise revenue for stormwater management programs, however little is known about the trends among the fees currently in existence. This research observes trends in the establishment, type and magnitude of user fees by analyzing location, population density, home value, and establishment for a comprehensive national stormwater user fee database with data for 1,490 user fees. The Equivalent Residential Unit (ERU), a SUF that charges based on impervious area, was the most prevalent fee type in all NOAA Climate regions of the U.S. except the West and West North Central. The Tier system, a SUF that charges differently for properties by defined categories, was the second most prevalent in all regions except the East North Central and West North Central. The ERU was found in larger cities with high population densities whereas flat fees, SUFs that charge a single rate for all properties, were found in smaller towns. Higher home values led to higher monthly fees for 28% of the municipalities analyzed. The Residential Equivalence Factor (REF), a SUF that charges based on runoff produced, was popular in municipalities with higher home values and the flat fee was popular in those with lower home values. The number of SUFs established increased near Phase I MS4 permit and Phase II small MS4 permit deadlines. / Master of Science

While a policy of more decentralized stormwater management is increasingly being pursued in areas containing new housing developments, the question arises as to how stormwater management is handled in existing settlements, where restructuring the drainage system is a much more complex affair and often requires the active involvement of property owners. Recognizing that the multidimensional objectives of stormwater management in settlements call for a range of local strategies, this article examines the interaction and strategic contribution of two key municipal institutions for regulating stormwater management, namely, compulsory connection and usage and stormwater charges, in order to examine how they meet these objectives when property owners are involved. The following questions are addressed: How do these two key institutions link the varied objectives of stormwater management with practical options for decentralization? Which institutional designs are capable of integrating property owners into a municipal stormwater strategy in a coherent manner? What is current local government practice? This article begins by analyzing the interactions between different objectives of stormwater management, the interplay of the two key institutions, and options for stormwater management on private properties. On this basis, we then present an empirical study of current practice in 44 medium to large cities in Germany. This shows that while local governments devise very different—and often inconsistent—institutional designs, decentralization is quite commonly pursued in existing settlements.

In the recent century, a process of urbanization has increased globally. Previously rural or natural land have been converted into impervious surfaces to make way for housing, industries, and roads. This anthropogenic process has resulted in an increased amount of surface runoff from precipitation, so-called stormwater. Stormwater can accumulate a range of pollutants when it flows over the impervious surfaces of our cities. These pollutants can have a negative impact on the lakes and streams that receive the stormwater from the urban environments. To reduce the environmental problems associated with the content of stormwater, various techniques have been developed for stormwater treatment, with the aim of reducing the pollutant load in the runoff before it enters the receiving waterbody. One such technology is stormwater biofiltration, also known as bioretention. Stormwater biofilters were developed in the USA in the early 90's and they utilize the natural water remediation properties of plant-soil systems. They are generally characterized by a vegetated submerged filter bed with an underlying drainage layer. They have shown to be an effective method for stormwater pollutant removal. The treatment processes take place both in the vegetation and in filter material. As th ematerial choices and design of the biofilters can vary, so can its treatment performance. Stormwater biofilters have grown in popularity in the last decades since their development and numerous studies have been conducted to evaluate the systems’ treatment efficiency. However, knowledge gaps still exist regarding their implementation in colder climates and the suitability of different configurations and materials. This study examines the removal performance of total and dissolved heavy metals (Cd (cadmium),Cu (copper), Pb (lead) and Zn (zinc)), phosphorus, nitrogen and total suspended solids (TSS) in three stormwater biofilters in a Swedish climate, located in central Malmö. The current biofilters are designed with different configurations of their filter media and are built with 1) sand-basedfilter material 2) sand-based filter material with a submerged zone and 3) filter media consisting of 50% sand-based material in combination with 50% pumice. The results showed that the treatment capacity of the biofilters with a filter media of only sand (biofilter S) and with sand as well as a submerged zone (biofilter S_SZ) was similar for all pollutants. The reduction of total levels of metals (> 85 %) and TSS (>90 %) was consistently high and similar to levels achieved in previous studies for both temperate and colder climates. The removal of dissolved metals was lower in comparison to the removal of the total metal fractions, but the dissolved fractions were still generally reduced in the effluent. A positive removal of total phosphorus and total nitrogen was overall displayed in the effluent from the two biofilters; however,leaching was shown for the dissolved fractions. For nitrogen (N) species, the concentrations in the runoff were generally below the detection limit for the analysis making it difficult to establish probable removal percentages. For the biofilter S_P, which contained a mix of sand and pumice, the removal capacity was lowerfor all parameters compared to the other designs. Overall, the pollutant removal performances are regarded to be satisfactory for biofilters S andS_SZ and their implementation suitable for the given site. However, further investigations should be performed during warmer seasons, especially regarding the removal of nutrients.

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No description available.

Vattenbrist blir allt vanligare i vårt samhälle och belastningen på vattenresurser och dricksvattensystemen ökar, även i Sverige. Det finns stora möjligheter att ersätta användningen av dricksvatten med vatten av lägre kvalitet för vissa ändamål, till exempel vid toalettspolning och bevattning. Att samla upp och använda dagvatten från tak och andra hårdgjorda ytor kan vara ett steg emot att använda mindre volymer dricksvatten. Många faktorer måste dock beaktas när ett sådant system ska implementeras. Vid sådana tillfällen kan en multikriterieanalys utföras. Water Investments for Sustainability Enhancement and Reliability (WISER) är ett Excel-baserat beslutsverktyg som är utvecklat för att underlätta transparent beslutsfattande kring dricksvattensystem och är baserat på multikriterieanalys. Detta arbete utvärderade möjligheterna att använda regn- och dagvatten som komplement till dricksvatten. Frågeställningarna undersökte vilka typsystem som finns för regn- och dagvattenåtervinning samt vilka hållbarhetskriterier (tekniska, sociala, miljömässiga och ekonomiska) som är lämpliga för att utvärdera dessa system som ett alternativ till dricksvattenanvändning. Beslutsverktyget WISER testades även i samarbete med en lokal VA-organisation på ett nytt exploateringsområde i Kistinge industriområde.   Metoden var en litteraturstudie och tillämpning av WISER i fallstudien. Två workshops anordnades där lokala intressenter från Laholmsbuktens VA och Halmstads kommun deltog. Där valdes kriterier för att bedöma fyra alternativa regn- och dagvattenåtervinningssystem: fastighetsnära insamling av regnvatten från tak med enskild eller gemensam magasinering, samt ett storskaligt system som samlar i regn- och dagvatten i dagvattendammar med enkel eller avancerad rening.   Resultatet visade att typsystem för regn- och dagvattenåtervinning varierar i komplexitet, men består vanligtvis av en uppsamlingsyta, magasinering, grovfilter och pumpar. Potentiella kriterier att använda vid utförande av en multikriterieanalys för regn- och dagvattensystem utvecklades och tillämpades i fallstudien. Resultatet visade att WISER var användbart som beslutsstöd för regn- och dagvattenåtervinning. För Kistinge industriområde var de mindre regnåtervinningssystemen som hade tak som uppsamlingsyta att föredra framför ett storskaligt system som samlar in både regn- och dagvatten. Alla system presterade dock på liknande nivå som att använda dricksvatten i stället, vilket tyder på att regnvattenåtervinning med dessa system inte nödvändigtvis innebär en hållbarhetsmässig fördel. / Today, problems caused by water shortages are increasing in frequency and magnitude even in Sweden. However, there are great opportunities to replace the use of potable water with water of a lower quality, for example when flushing toilets and irrigation. Collecting and recycling stormwater from roofs and other hardened surfaces can be a step towards using less potable water. There are multiple factors that need to be considered when implementing such a system, and a way to oversee the different perspectives is by doing a multi-criteria analysis (MCA). This is a common decision support method when analyzing complex problems. Water Investments for Sustainability Enhancement and Reliability (WISER) is a multi-criteria analysis decision tool that was developed to facilitate transparent decision-making regarding drinking water systems. The aim of this project was to apply and evaluate WISER to analyze various aspects of using stormwater as a supplement to potable water. The main questions in this report included what types of systems are available for stormwater recycling. Moreover, what sustainability criteria (technical, social, environmental, and economic) are appropriate to use to evaluate those systems as an alternative to drinking water use? The decision tool WISER was also applied to see if it can be used to determine whether implementing a stormwater system is a sustainable alternative. The case study was an industrial area called Kistinge in the Southwest of Sweden.   The method was based on a literature study and applying the WISER tool in the case study. Two workshops were organized where local stakeholders from the municipality in Halmstad and the local water and wastewater organization LBVA participated in the selection of relevant criteria for the case study and to assess four alternative stormwater recycling systems in WISER: local or centralized collection from roofs, and centralized collection with and without advanced treatment. Calculations were also made to assess drinking water savings, based on local precipitation data and assumptions regarding collection areas and system designs. The result of the study showed that the available stormwater systems and their area of use vary. Most common type of stormwater recycling systems include a collection area, pipes and storage, a filter, and a pump. Potential criteria to use in a multi-criteria analysis for stormwater recycling systems were developed and evaluated on the case study. The results from the MCA showed that for this industrial area, the small stormwater recycling systems using roofs as the collection area were preferable over bigger systems which managed stormwater from the whole industrial area. However, all systems received a similar index compared to using potable water instead, indicating a weak sustainability performance.

Big-box Urban Mixed-use Developments (BUMDs) are mixed-use developments with a consistent typology that incorporate big-box retailers in a central role. They are also becoming popular in the Atlanta region. While BUMDs serve an important economic role, they also cause issues with stormwater. This study explores integrating a on-site approach to stormwater management into the design of BUMDs. These new designs not only significantly lower the amount of stormwater run-off, but also have potential for better, more attractive, developments.

The global move to more sustainable and renewable energy sources causes increased fluctuations in theelectric market. That fact combined with the Swedish regulations on micro producers make high levels ofself-use critical and have increased the interest in energy storage of energy from intermittent sources.Cooperation with Eksta AB have provided the opportunity to evaluate an innovative energy storage conceptfor a future exploitation area of around 17,2 hectares planned residential and urban area. This bachelorthesis studies the potential of using stormwater management ponds for small-scale energy storage in theform of pumped hydro energy storage (PHES). The focus is on storage of surplus energy from a solarenergy system designed for micro production and local energy supply. However, it also evaluates thepotential of using the equivalent dimensions for energy storage which storage level only change whenbuying or selling electricity at market prices for arbitrage purposes.Potential in the form of financial benefit and increased self-use of solar energy are studied through aquantitative methodology that, in the case of storing surplus energy from a solar system, use a simulationmodel developed for this thesis that takes Eksta´s contractual electric specifications into account. Toevaluate the case of energy storage for arbitrage a simulation model is used in the form of an algorithmbaseddrive strategy named “Optimal”, which has been recreated from research in the field of energy storageand drive strategies. The level of innovation is high on account of including such as energy additions to thestorage from rain water management, energy losses from dispersion of stored stormwater to surroundingground layers, it´s novel focus on a stormwater pond for energy storage, the rarely studied combination ofPHES and small scale solar systems and finally that the dimensions of the pump and turbine that is neededin PHES is based on PaT (pump as turbine) technology, allowing the reverse drive of a centrifugal pumpto operate as a turbine.Sensitivity analysis is included to increase the understanding of PHES-stormwater systems in the case of Eksta and as a concept for energy storage. The work also includes a brief examination of relevant regulationsin order to supply a wider perspective.The result shows that the implementation of a PHES-stormwater system during the years 2018 and 2019increased the self-use of generated solar energy by 28,59 % and provide the joint financial benefit of 5989SEK. The simulation model of energy storage for arbitrage during the years 2018 and 2019 resulted in thecombined financial benefit of 699 SEK when “Optimal” operation strategy is used and 678 SEK with apractically applicable operation strategy.The main conclusion is that PHES-stormwater systems as an energy storage for small-scale solar surplushas high potential to increase the self-use of solar energy but relatively low potential to increase the financialbenefits of small-scale solar systems. From the sensitivity analysis it can be concluded that the simulatedPHES-stormwater system is sensitive to small and medium ranged changes in storage capacity, efficiency,rate of dispersion, set electrical buying price and selectivity of which hours to empty the storage. This whilebeing generally insensitive to small and medium ranged variations in installed peak effect of the solar system,filling/emptying time and the relative size of the turbine compared to the pump.The conclusion from the simulation of arbitrage application is that the potential for financial benefit inthese circumstances is extremely low. The sensitivity analysis lead to the conclusion that the system issensitive to small and medium ranged variations in storage capacity, efficiency, filling/emptying time andmarginal operation costs.Besides the limited financial benefit, other potential hindrances may be the legality of connecting the systemelectrically, lack of financial benefits given to larger but still small-scale solar systems and the eventuality ofdisrupting the main function of the stormwater pond, which is purifying stormwater.

Hållbar dagvattenhantering är ett koncept som, i takt med ökade regnmängder och tät bebyg-gelse, blivit mer och mer uppmärksammat inom stadsplanering. Det handlar om att hitta ettmer robust system för att hantera det dagvatten som uppstår genom att kombinera både rör-och ledningssystem med andra lösningar som fördröjer och renar vattnet innan det når ut tillrecipienten. Samtidigt är samhällsbyggnadsprocessen ofta komplex och involverar många olikaaktörer vilket också gäller för dagvattenhantering. I och med detta uppstår ett antal utmaningarsom problematiserar processen mot att få till en mer hållbar dagvattenhantering. Detta arbetesyftar till att komma underfund med de utmaningar som finns när det kommer till samverkanrelaterat till dessa frågor samt att klargöra hur samverkan kan förbättras för att uppnå en merhållbar dagvattenhantering. I arbetet görs en litteraturstudie vars främsta syfte är att reda ut begreppet samverkan, vad sombidrar till god samverkan och vilka positiva effekter samverkan kan ha i ett projekt. För att sedanreda ut vilka utmaningar och framgångsfaktorer som finns kring dagvattenfrågan genomförs enkvalitativ studie i form av sju intervjuer med personer som på olika sätt arbetar med dagvatten.Dessutom används två analysverktyg, Fyrfältaren och Forum-Arena-Court, för att sortera in debehov och förbättringar som behövs arbetas med. Det framkommer att det finns en del problematik kopplat till samverkan och dagvattenhantering.Det finns främst förbättringspotential när det kommer till att hantera de olika perspektiv ochintressen som kommer med att ha många olika aktörer involverade. Där framstår det som viktigtatt dagvattenfrågan är med tidigt i processen och att det skapas en gemensam målbild kring vadsom ska genomföras i projektet. Utöver detta finns det även en del utmaningar när det kommertill tydlighet kring hur projektet ska genomföras. Här är det viktigt att det finns tydliga riktlinjerfrån kommunens sida samt att se till att det finns en kontinuitet och dialog. Sammantaget finnsdet behov av förbättring kring samverkan och detta skulle kunna möjliggöra vägen mot en merhållbar dagvattenhantering. / Sustainable stormwater management is a concept that, with increasing amounts of rain and densesettlements, has been paid more attention to in urban planning. It revolves around finding amore robust system for managing stormwater by combining systems using pipes with othersolutions that delay and clean the water before it reaches the recipient. At the same time, theprocesses within urban planning are complex and involve many different parties which is alsotrue for stormwater management. Consequently, a number of challenges arise which complicatesthe process of achieving sustainable stormwater management. This study aims to find what thecooperation challenges are and to find out how cooperation can be improved to achieve a moresustainable stormwater management. In the study, a literature study is conducted with the purpose of investigating the conceptof cooperation, what good cooperation consists of and what positive effects it might have ina project. To figure out what the challenges and the factors of success are when it comes tostormwater management, a qualitative study consisting of seven interviews with people workingwith storm water is conducted. In addition, two tools for analysis, Forum-Arena-Court andFyrfältaren, are used to categorize the needs and improvements that need working with. There appears to be some issues regarding cooperation in connection to stormwater management.Mainly, there is potential for improvement when it comes to handling the different perspectivesand interests that come with having several different parties involved. It seems important to makesure that stormwater management is included early in the process and that there is a commonvision regarding what is supposed to be achieved within the project. Moreover, there are also afew challenges in regards to clarity of how the project is to be carried through. It is important tohave clear guidelines from the municipality’s side as well as continuity and dialogue throughoutthe project. To summarize, there are a few areas where improvement is needed when it comesto cooperation and this could possibly lead the way towards a more sustainable stormwatermanagement.