As rain events are likely to intensify and the proportion of impervious areas in cities increases, greater demands are put on stormwater management. Nature-Based Solutions (NBS) have become more popular over the past decades to be integrated into the stormwater strategy in order to reduce the volume of runoff in cities. For NBS to be effective over long term, maintenance must be prioritized. This study addressed two questions, what are the difficulties in modeling (lack of) maintenance over time and what are the consequences in terms of water quantity with inadequate maintenance on the long- term efficiency of NBS?. This was found by developing a hydrodynamic model in SWMM, where three NBS types were modeled, rain garden, permeable pavement, and infiltration trench. The efficiency of maintenance was investigated by creating several scenarios where different parameters were identified to represent maintenance. The parameters were varied for different precipitation events, as the effect of maintenance depends on the type of precipitation used. In general, inadequate maintenance has been proven to have little impact on rain events with a return period of 2-years, while a large difference could be seen for intense rains. Two consequences as a result of an absence of maintenance are overgrown vegetation and clogging of the media. Clogging was investigated for all three NBS types, and was found to have a large impact on its efficiency over time. The result also shows that despite the inadequate management, NBS can still contribute to manage stormwater, but with lower efficiency. / I takt med att regnen kommer att intensifieras och andelen hårdgjorda ytor i städer ökar, så ställs allt högre krav på dagvattenhantering. Naturbaserade lösningar (NBS) har under senaste decenniet blivit alltmer populära att integrera i dagvattenstrategin för att minska mängden dagvatten i städer. För att NBS ska vara effektiv över tid behöver skötseln prioriteras. Den här studien adresserar två frågor, vilka är svårigheterna med att modellera (bristfällig) underhåll över tid och vad är konsekvenserna av bristfälligt underhåll på NBS effektivitet över tid. Detta besvarades genom att skapa en modell i SWMM där tre NBS typer modellerades, regnbädd, genomsläpplig yta och infiltrationsdike. Effekten av underhåll undersöktes genom att skapa flera scenarion där olika parametrar som identifieras för att representera underhåll. Parametrarna förändrades sedan för olika nederbördstyper, då effekten av underhåll beror på vilken nederbördstyp som studeras. Bristfälligt underhåll sågs generellt inte ha någon större påverkan på 2-års regn, medan en stor differens kunde ses för de intensiva regnen. Igenvuxen vegetation på ytan och igentäppning av media, som konsekvens av undermåttligt underhåll, undersöktes bland annat för de tre NBS typerna, och resultatet visade att det har stor påverkar på dess effektivitet över tid. Resultatet visar också, trots otillräckligt underhåll, att kan NBS ändå bidra till att hantera dagvatten, men med betydligt lägre effektivitet.

Sustainable changes become increasingly urgent with the climate crisis, which makes it necessary to study the human-environmental relationship. Tiveden National Park is a shared environment, and this thesis studied how sustainability was interpreted and implemented in the management of the park. The overall aim was to study how different scales of government balance ecological, economic, and social pillars of sustainability within their occupation. To precise the study, the aim specifically was to study how the balancing of ecological, economic, and social aspects is implemented in the park’s management by Region Västra Götaland, Region Örebro, Västra Götaland county administration board, Örebro county administration board, Askersund municipality, Karlsborg municipality, and Laxå municipality. After presenting a theoretical framework and interviewing ten informants at the previously mentioned organizations, the resulting analysis presented that resource scarcity and ecological threats were frequent sustainability problems at all organizations. Dialogue, positive attitudes, and long-term thinking were used by the organizations to balance sustainability conflicts of interest. The larger the spatial responsibility of each organization was, the more interdisciplinary the organization had capacity to work. The organizations interpreted sustainability similarly, but prioritized the aspects differently depending on the person’s affiliation.

Bangladesh is one of the most vulnerable countries to climate change, with coastal areas being especially vulnerable. Along the Bangladeshi coast lies mangrove forests that protect against storm surges, tropical cyclones, SLR, coastal erosion, and salt-water intrusion. On Char Kukri Mukri, a remote island in the Bay of Bengal, Keora-species (Sonneratia apetala) mangroves are planted. The forest is virtually a monoculture in degradation and thus needs restoration through enrichment. Therefore, this study aimed to explore the opportunities and limitations of mangrove enrichment as climate adaptation on Char Kukri Mukri. We conducted semi-structured interviews with local communities and other key stakeholders and analysed soil and water samples along the island's south coast to assess this. Our results indicate that the soil is highly saline, which, combined with projected climate impact, limits the abilities of more sensitive mangroves to survive there. Climate impacts severely affect the lives and livelihoods of the people living on Char Kukri Mukri. Successful adaptation requires further involvement of local communities, site-specific solutions, and a holistic approach to adaptation. However, a hindrance to adaptation measures is the lack of resources to fund large-scale projects, which leads to beneficiaries being required to provide money and land themselves to be considered for projects. This risks systematically excluding the landless poor, and there is therefore a need to reform adaptation financing systems so that measures benefit the most vulnerable. / Bangladesh är ett av de länder i världen som är mest sårbara för klimatförändringarna. Kustområdena är mest känsliga. Längs Bangladeshs kust finns mangroveskogar, som skyddar mot klimateffekter som stormar, cykloner, havsnivåhöjning, kusterosion, och saltvattenintrång. På Char Kukri Mukri, en avlägsen ö utanför Bangladeshs centralkust i Bengaliska viken, har mangrover av arten Keora (Sonneratia apetala) planterats. Skogen är praktiskt taget en monokultur som håller på att förstöras, och det finns därför ett behov av att restaurera skogen. Denna studie syftade till att undersöka möjligheterna och hindrena för restaurering av mangroveskogarna som klimatanpassning på Char Kukri Mukri. För att uppnå detta genomförde vi semistrukturerade intervjuer med lokalbefolkningen och andra nyckelintressenter, och analyserade jord- och vattenprover tagna vid öns sydkust. Våra resultat indikerar att jorden har hög salthalt, vilket i kombination med ökade klimateffekter minskar mer känsliga mangrovearters möjligheter att överleva i dessa områden. Klimateffekter påverkar människorna och deras försörjning på Char Kukri Mukri i hög grad. Lyckad klimatanpassning kräver mer inkludering av lokalbefolkningen i initativ, platsspecifika lösningar, samt ett holistiskt tillvägagångssätt. Resursbrist hindrar dock investeringar i storskaliga och långsiktiga projekt, vilket gör att förmånstagare behöver bidra med pengar och mark till projekten. Detta gör att fattiga människor som inte äger mark systematiskt exkluderas ur anpassningsprojekten. De nuvarande finansieringssystemen behöver därför reformeras för att projekten ska ge fördelar till de människor som är mest sårbara för klimatförändringarna.

The recognition of nature in the resolution of societal challenges has been growing in relevance. This recognition has been associated with the development of new concepts from science and policy such as natural capital, ecosystem services, green infrastructure, and more recently Nature-Based Solutions (NBS). NBS intends to address societal challenges in an effective and adaptive form providing economic, social, and environmental benefits. The overall aim of this PhD thesis is to develop an environmental and economic assessment of NBS for highly urbanised territories based on rationales and models underpinning ecosystem services, urban/landscape ecology, and life cycle thinking approaches. This combined evaluation approach would help to better understand if NBS are cost-effective or not. The aim is developed according to four specific objectives. The first objective corresponds to the characterisation of NBS in relation to urban contexts and the problematics that they can help to address or mitigate. To achieve this objective a critical review on the study of the relationship between NBS, ecosystem services (ES) and urban challenges (UC) was developed. As a main output, a graph of plausible cause-effect relationships between NBS, ES and UC is obtained. The graph represents a first step to support sustainable urban planning, moving from problems (i.e. urban challenges) to actions (i.e. NBS) to resolutions (i.e. ES). The second objective corresponds to the definition of an adequate set of biophysical and monetary assessment methods and indicators to evaluate the value of NBS in urbanised contexts. To achieve this objective, a review of existing methods on ecosystem services valuation, life cycle cost analysis and life-cycle assessment are developed. The review takes into account specific constraints such as easiness to use and availability of data. At the end, potential methods and indicators were selected, which will be later integrated in the combined assessment framework. The third objective corresponds to the design of a combined assessment framework integrating methods from life cycle assessment, landscape/urban ecology and ecosystem services that quantifies the environmental and economic value of NBS informing about the cost-effectiveness of its entire life cycle. To achieve this objective, a conceptual framework is developed. From it, a system dynamics model of ecosystem (dis)services is developed and coupled with a life cycle assessment method. The combined evaluation is tested with a relevant NBS type (i.e. urban forest) in a case study in the metropolitan area of Madrid. The fourth objective is the development of a decision support (DSS) tool that integrates the assessment framework as part of iterative design processes in urban planning and landscape design. The DSS intends to enhance the interrelation between science, policy and planning/design. To achieve this objective a user-friendly web-based prototype DSS on NBS, called NBenefit$®, is developed. The prototype DSS provides the user a simple form of quantifying the provision of multiple ES and costs over the entire life cycle (implementation, operational life, and end-of-life) of NBS. This thesis contributed to the characterisation of NBS and its environmental and economic assessment to inform urban planning and landscape design processes, allowing decisions that are more informed. / Il riconoscimento della natura nella risoluzione delle sfide sociali è diventato sempre più importante. Questo riconoscimento è stato associato allo sviluppo di nuovi concetti provenienti dalla scienza e dalla politica, come il capitale naturale, i servizi ecosistemici, le infrastrutture verdi e, più recentemente, le soluzioni basate sulla natura (NBS). NBS intende affrontare le sfide della società in una forma efficace e adattabile fornendo benefici economici, sociali e ambientali. Lo scopo di ricerca di questa tesi di dottorato è quello di sviluppare una valutazione ambientale ed economica delle NBS per territori altamente urbanizzati basata su logiche e modelli che hanno alla base i servizi ecosistemici, l'ecologia urbana e paesaggistica e degli approcci di approcio life cycle. Questo quadro di valutazione combinato aiuterebbe a capire meglio se le NBS sono costo effetive e se contribuiscono a uno sviluppo resiliente e sostenibile. Questo scopo di ricerca è sviluppato secondo quattro obiettivi specifici. Il primo obiettivo corrisponde alla caratterizzazione delle NBS in relazione ai contesti urbani e alle problematiche che possono aiutare ad affrontare o mitigare. Per raggiungere questo obiettivo è stata sviluppata una revisione critica dell letteratura sullo studio della relazione tra NBS, servizi ecosistemici (ES) e sfide urbane (UC). Come risultato principale, si ottiene un grafico delle relazioni causa-effetto plausibili tra NBS, ES ed UC. Il grafico rappresenta un primo passo per supportare la pianificazione urbana sostenibile, passando dai problemi (es. UC) alle azioni (es. NBS) alle risoluzioni (es. ES). Il secondo obiettivo corrisponde alla definizione di un set di metodi e indicatori di valutazione biofisica e monetaria adeguate per valutare il valore della NBS in contesti urbanizzati. Per raggiungere questo obiettivo, viene sviluppata una revisione dei metodi esistenti sulla valutazione dei servizi ecosistemici, l'analisi dei costi del ciclo di vita e la valutazione del ciclo di vita. La revisione tiene conto di vincoli specifici come la facilità d'uso e la disponibilità dei dati. Alla fine, sono stati selezionati potenziali metodi e indicatori, che saranno successivamente integrati nel quadro di valutazione combinato. Il terzo obiettivo corrisponde alla progettazione del quadro di valutazione combinato, integrando metodi di valutazione del ciclo di vita, ecologia paesaggistica / urbana e servizi ecosistemici che quantifica il valore ambientale ed economico della NBS informando sull'efficacia in termini di costi del suo intero ciclo di vita. Per raggiungere questo obiettivo, prima viene sviluppato un quadro concettuale. Da esso, viene sviluppato un modello di dinamica di sistemi per calcolare i servizi (e disservici) ecosistemici, il quale è interrelazionato con un metodo di valutazione life cycle. Questa valutazione combinata viene testata con un tipo di NBS pertinente (foresta urbana) in un caso di studio nell'area metropolitana di Madrid. Il quarto obiettivo è lo sviluppo di uno strumento di supporto decisionale (DSS) che integri il quadro di valutazione come parte dei processi di progettazione iterativa nella pianificazione urbana e nella progettazione del paesaggio. Il DSS intende migliorare l'interrelazione tra scienza, politica e pianificazione / progettazione. Per raggiungere questo obiettivo è stato sviluppato Nbenefit$® un prototipo di DSS online per la valutazzione NBS di facile uso. Il prototipo DSS fornisce all'utente una forma semplice per quantificare multipli ES e costi (internalizatti o no) durante l'intero ciclo di vita (implementazione, vita operativa e fine vita) del NBS. In conclusione, questa tesi ha contribuito alla caratterizzazione di NBS e alla sua valutazione ambientale ed economica per informare i processi di pianificazione urbana e progettazione del paesaggio, consentendo decisioni più informate.

Considering the potential for natural wetlands to store and retain water in the landscape,restored and constructed wetlands are increasingly implemented as Nature‐BasedSolutions (NBS) to mitigate downstream flooding. However, there is a frequent lack ofknowledge of the performance of NBS, and particularly wetlands, and how to best selectperformance indicators to measure their effectiveness. The aim of this study was to assessthe flood regulation services of multiple constructed wetlands at catchment scale. TheSWAT+ model was used to assess the impacts of 35 constructed wetlands in the 193 km2Råån catchment in southwest Sweden. The assessment was based on a paired simulationscenario, with and without wetlands, and performance was evaluated based on impacts onthe downstream river hydrograph (peak flow rate, time-to-peak, recession curve shape,daily streamflow average) as well as event-based (daily average streamflow for differentprecipitation ranges), descriptive (average wetland storage capacity), consequential(overbank flooding) and social (social acceptance) indicators. The results implied that theflow regulating capability of the modeled wetlands was directly related to their outflowmechanisms. The wetlands had an average storage capacity of 0.38 m3 per m2 area butbecause the wetlands seemed to frequently exceed their maximum storage capacity duringhigh flow events, and the excess water was immediately spilled downstream, the wetlandsprovided limited flood regulation services. There were no visible impacts on thehydrograph-related indicators and the daily streamflow average was reduced by anegligible 0.02%. Furthermore, there were no significant differences in wetlandperformance between small and heavy rainfall events and the model output showed nosigns of overbank flooding for either wetland scenario. In terms of social acceptance, recentwetland projects in Råån catchment seem to have been well-received by farmers andlandowners in the area. However, lack of wetland-specific data, such as volume and dailyinflow and outflow data, as well as other model uncertainties, motivated a low confidencegrade for the indicators. In fact, if indicator values are to be useful tools in the futureintegration of wetlands as nature-based solutions, in-situ monitoring data of wetland waterbalance components are required. To support future policies and decision-making, adaptedtools and further research are needed to assess the impact of NBS on upstream-downstream processes. / Naturliga våtmarkers förmåga att hålla kvar och lagra vatten i landskapet gör attrestaurerade och anlagda våtmarker alltmer implementeras som naturbaserade lösningarför att mildra översvämningar i nedströms belägna områden. Det råder dock brist påkunskap om hur effektiva naturbaserade lösningar är och hur nyckelindikatorer bäst kanväljas för att mäta hur väl dessa system fungerar. Syftet med denna studie var att utvärderaanlagda våtmarkers förmåga att mildra översvämningar i ett avrinningsområde. SWAT+modellen användes för att bedöma påverkan av 35 anlagda våtmarker i Råånsavrinningsområde (193 km2) utanför Helsingborg. Bedömningen baserades på ettsimuleringspar, med och utan våtmarker, och effektiviteten utvärderades baserat påhydrografens egenskaper (flödestopp, stegringsfasen, recessionsfasen, daglig medel-vattenföring) samt med en nederbördsbaserad (daglig medelvattenföring för olikanederbördsintervall), beskrivande (genomsnittlig lagringskapacitet), konsekvensbaserad(översvämmad mark) och social (social acceptans) indikator. Resultatet antydde att denflödesreglerande förmågan hos de modellerade våtmarkerna var direkt kopplad till derasutflödesmekanismer. Våtmarkerna hade en genomsnittlig lagringskapacitet på 0.38 m3 perm2 yta men eftersom de ofta verkade överskrida sina maximala lagringskapaciteter underhögflöden, och överskottsvattnet omedelbart släpptes igenom nedströms, tillhandahöllvåtmarkerna en mycket begränsad flödesdämpande funktion. Det fanns inga synligaeffekter på de hydrografrelaterade indikatorerna och den dagliga medelvattenföringenminskade med försumbara 0.02%. Dessutom sågs inga signifikanta skillnader mellan småoch kraftiga nederbördshändelser och modellen visade inga tecken på översvämmad markför något av våtmarksscenarierna. Vad gäller social acceptans tycks de senastevåtmarksprojekten i Rååns avrinningsområde ha tagits emot väl av lantbrukare ochmarkägare i området. Bristen på våtmarksspecifika data, såsom volym och dagliga in- ochutflödesdata, samt andra modellosäkerheter medförde dock ett lågt förtroende förindikatorerna. Om indikatorvärden ska vara användbara verktyg i den framtida integ-reringen av våtmarker krävs uppmätta data över våtmarkernas vattenbalanskomponenter.För att stödja framtida beslutsfattande behövs även anpassade verktyg och ytterligareforskning för att bedöma påverkan av naturbaserade lösningar på uppströms-nedströmsprocesser.

Diese Arbeit beschäftigt sich mit Aerial Rivers („luftgetragenen Flüssen“), den bevorzugten Wegen des Flusses von Feuchte in der Atmosphäre. Ziel ist es, die Voraussetzung für deren Integration in aktuelle Paradigmen der Wasserwirtschaft zu schaffen. Im Mittelpunkt der Arbeit stehen Amazonien und die angrenzenden Gebiete, also Regionen der Erde, in denen sich derzeit der Landnutzungswandel mit am schnellsten vollzieht. Aus theoretischer Sicht wird das Wissen über die Verbindung zwischen Aerial Rivers und Oberflächenflüssen erweitert. Mit Hilfe eines Algorithmus zur Verfolgung des atmosphärischen Feuchtigkeitstransports werden die Auswirkungen von entferntem Landnutzungswandel in Windrichtung auf die Niederschlagsmenge einer Zielregion quantifiziert. Die räumliche Heterogenität des Einflusses der gesamten Quellevapotranspirationsfläche (precipitationsehed) auf die/den empfangene/n Niederschlagsmenge/Oberflächenabfluss der Zielregion wird untersucht und führt zur Identifizierung der „Most Influential Precipitationshed“ (MIP), der für Managementzwecke relevantesten Teilfläche. Ein Aerial River-Managementbeispiel für Santa Cruz (Bolivien) zeigt, dass die strategische Wiederaufforstung im MIP sowohl die Niederschlagsmenge als auch den empfangenen Oberflächenabfluss erhöht und 22%-59% des zukünftigen Wasserbedarfszuwachses einer schnell wachsenden Stadt decken kann. Weiterhin werden sozio-technische Regime entlang von Aerial Rivers, die zu Extremereignissen wie Megadürren beitragen können, mit Hilfe der sozialwissenschaftlichen Methode der Multi-Level-Perspektive (MLP) untersucht. Ursachen wie Bodenpolitik und Marktinterventionen in Brasilien und Bolivien steuern weit entfernte kolumbianische Energieregime und deren Wandel. Aerial Rivers sind also zentral für zukünftiges Gewässermangement einschließlich Wasserkraft; ihr Management erfordert jedoch eine ganzheitliche Betrachtung der gesellschaftlichen Schnittstellen über administrative Grenzen und Sektoren hinweg. / Aerial rivers are the preferential pathways of moisture flows in the atmosphere. They connect the atmosphere, the water system, and the land system. This thesis aims to provide knowledge for integration of aerial rivers into management of these systems. It focuses on Amazonia and adjacent areas, which collectively experience some of the most rapid land use change on the planet. This thesis further develops three key aspects (theoretical, technical, and societal) of knowledge concerning aerial rivers. From a theoretical aspect, it advances the knowledge of connection between aerial rivers and surface rivers. Using a moisture tracking algorithm, the impact from upwind land use change via aerial rivers on target regions’ runoff reception is quantified. Spatial heterogeneity in the influence of the precipitationshed on runoff reception of the target region is found, implying a need to determine the most influential precipitationshed (MIP) for management purposes. From a technical aspect, the work demonstrates an aerial river management example for a rapidly growing city. It is shown that strategic reforestation in the MIP can increase both rainfall and runoff reception and secure 22%-59% of a rapidly growing city’s future water needs. Finally, the work explores the societal aspect of aerial river management. Socio-technical regimes along aerial rivers contributing to extreme events of mega-drought were traced through the social scientific method of multi-level perspective. It reveals that the source regimes such as land policy and market interventions in Brazil and Bolivia govern remote Colombian energy regimes and their transitions through aerial rivers. These findings show that aerial rivers are relevant and viable options for the development of future water resources - including hydropower - but their management will require a holistic consideration of the various societal interfaces as they cross jurisdictional boundaries and sectors.

With increased urbanization and climate change, heavy rainfall events and urban floods are becoming more frequent. To meet the demands for effective climate adaptation strategies and mitigation measures, Nature-Based Solutions (NBS) have received increased attention. The city of Stockholm has a long history of implementing such solutions for local stormwater management, to capture surface runoff by infiltration and retention at its source. Implementing urban trees with skeletal soil is a well-established approach with the potential as an effective mitigation measure. Nevertheless, the literature review found few studies with evidence of their effectiveness in terms of flood risk mitigation. To contribute to this knowledge gap, the aim of this study was to quantitatively assess the effectiveness of urban trees with skeletal soils. By investigating their effectiveness in reducing flood extent, runoff volumes, and peak flows during different rainfall events, the results are thought to provide new insights and support decision-makers. In fulfilling the study objectives, the hydrological functions of plant beds with skeletal soils were investigated, and an urban flood model was developed within the MIKE+ 2D Overland Module. Three scenarios, including a baseline scenario and two full-scale implementations of skeletal soils, were evaluated under different design storms. The results revealed that urban trees with skeletal soils have low effectiveness in flood risk reduction under heavy rainfall events, but are an effective measure for rainfalls with low return periods. For flood risk mitigation, this study emphasizes a hybrid approach, combining multiple NBS with traditional grey infrastructure. Uncertainties related to model performance and hydrological parameters raised concerns about the reliability of the results. Therefore, plant beds with skeletal soils should not be disregarded, but require further investigations. This study recommends alternative modelling approaches, such as coupling the 2D overland flow model with a 1D network model, and emphasizes the need for comprehensive analyses, empirical data, and field measurements. Future research should explore the collective impact of various NBS, and incorporate economic valuation through cost-benefit analysis (CBA). / Med en ökad urbanisering och påverkan av klimatförändringar blir intensiva nederbördshändelser och stadsöversvämningar allt vanligare. För att möta kraven på mer effektiva strategier för klimatanpassning och riskbegränsande åtgärder har naturbaserade lösningar fått ökad uppmärksamhet. Stockholms stad har en lång historia av att använda sådana lösningar för lokalt omhändertagande av dagvatten, med fokus på att fånga upp ytavrinning genom infiltration och fördröjning. En väletablerad metod innefattar användandet av stadsträd med skelettjordar, med potential som en effektiv skyfallsåtgärd. Trots detta visade litteraturstudien att det finns begränsat vetenskapligt stöd för deras effekt när det gäller översvämningshantering. För att fylla denna kunskapslucka syftar denna studie till att kvantitativt bedöma effekten hos stadsträd med skelettjordar. Genom att analysera deras effekt när det gäller att minska översvämningsmängder, avrinningsvolymer och toppflöden under varierande nederbördshändelser hoppas studien kunna bidra med nya insikter samt stödja beslutsfattare. För att uppnå dessa mål genomfördes en analys av de hydrologiska funktionerna hos skelettjordar, och en skyfallsmodell togs fram inom ramen för MIKE+ 2D Overland Module. Tre scenarier, inklusive ett nulägesscenario samt två fullskaliga användningar av skelettjordar, utvärderades under varierande typregn. Resultaten visade att skelettjordar har generellt låg effekt vid intensiva regn, men kan betraktas som en effektiv åtgärd för dagvattenhantering vid normala flöden. För att minska risken för översvämningar betonar denna studie vikten av att kombinera flera naturbaserade lösningar med traditionell grå infrastruktur. Osäkerheter relaterade till modellens prestanda och hydrologiska parametrar väckte dock tvivel kring resultatens tillförlitlighet. Således bör stadsträd med skelettjordar ej helt förkastas som skyfallsåtgärd. Studien föreslår alternativa modelleringsmetoder, såsom att koppla 2D-modellen med en nätverksmodell, samt understryker behovet av avancerade analyser och empiriska data för att förbättra modellens precision och tillförlitlighet. Framtida forskning bör inriktas mot att undersöka den samlade effekten av olika naturbaserade lösningar samt inkludera ekonomisk värdering genom kostnadsnyttoanalys.

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This research explores the potential of retrofitting enhanced or extended-depressed tree pits (ETPs/EDTPs) around existing street trees to bolster pre-development hydrological processes in two Hamiltonian neighbourhoods to help satisfy their social, economic, and environmental needs and work toward the Sustainable Development Goals (SDGs). Using QGIS and openly available data to create catchment areas, establish the feasibility of a 20:1 catchment to pit area ratio, and investigate the performance of five available structured soil cells, the innovative Analytical Probabilistic Model (APM) for Bioretention systems was adapted to conduct a parametric sensitivity analysis and subsequently compute the Road Runoff Reduction Efficiency (RRRE) of the designs under different climatic scenarios. The catchment to pit area ratio, design storage depth, and final infiltration rate were found to have a significant impact on the RRRE while the average evapotranspiration rate did not. Based on a 75% efficiency cut-off, and assuming a 20:1 catchment to pit area ratio, the shallowest two depths were deemed ineffective in all final infiltration rate scenarios while the largest depth provided efficiencies greater than 75% runoff reduction even when faced with the lowest rate of 6 mm hr-1. Comparing the RRRE during current climatic conditions to a simulated 2050s winter suggests that the RRRE of the deepest implementation is impacted only half as much as the shallowest; larger systems are more resilient. This research has reinforced the versatility and efficiency of the Analytical Probabilistic Model for modeling system performance of LIDs and ETPs, supports the prominent findings of the efficacy of enhanced tree pits to significantly contribute to urban stormwater management and re-establish more natural and sustainable hydrologic processes, and promotes them as a key to reaching the SDGs in Hamilton, Ontario. / Thesis / Master of Applied Science (MASc) / The Sustainable Development Goals call for action from every member of society. This research explores the potential Stormwater Management Engineers have to do so by retrofitting street trees with Enhanced or Extended-Depressed Tree Pits, increasing rooting volume and offering the tree more water from the adjacent road to simultaneously meet the natural needs of the tree and reduce urban runoff.

The view on stormwater has changed in recent years, considering the ongoing climate change. By implementation of blue-green infrastructure, it is possible to locally delay and purify stormwater, promoting the natural cycle. At the same time the pipeline network can be relieved and reduce the risks of flooding. With these facilities, sustainable urban development can be achieved, which is increasingly demanded in the construction industry today. The purpose of this study has been to identify sustainable suggestions for implementation in newly developed environments for stormwater management. This was done by leveraging knowledge to meet current and future needs for stormwater delay and purification. To identify suitable sustainable suggestions, several factors influencing the choice of facility were inspected, with an emphasis on costs and capacity. The research questions for this study were answered through interviews with professionals in the construction industry. This was done to gain a deeper understanding of design, costs, and capacity. The interview questions were based on the literature review conducted prior to the interviews. The literature review laid the ground for the theoretical part on which the interview questions were based. To identify factors influencing costs and capacity in the choice of facility, questions addressing these issues were included in the interview, where respondents were asked to rate the cost of different facilities on a scale from 1-10. The results of the study signify that sustainable stormwater management suggestions should involve blue-green infrastructure. Examples include ditches, permeable pavements, and stormwater ponds. These mimic the LOD (Local management of stormwater) principle, which involves managing stormwater locally where it occurs. The design must be done according to standards, which is demonstrated by the ability to manage both current and future needs for different types of flows. Various factors influence the choice of facility, including site conditions, drainage area size, existing facilities or infrastructure, requirements, guidelines, regulations, and flexibility, all of which make each project unique and require consideration of these factors. Finally, the factors of cost and capacity will affect each other, but the primary goal of addressing social, economic, and ecological aspects will always take precedence. / Synen på dagvatten har förändrats de senaste åren, med betraktande på de kontinuerliga klimatförändringarna. Genom att integrera blågrön infrastruktur är det möjligt att fördröja och rena dagvattnet lokalt, vilket främjar det naturliga kretsloppet. Samtidigt som ledningsnätet kan avlastas och minska riskerna för översvämningar. Med dessa anläggningar är det möjligt att uppnå en hållbar stadsutveckling, vilket är ett allt större krav idag i bygg- och anläggningsbranschen. Syftet för denna studie har varit att identifiera hållbara åtgärdsförslag för att kunna implementera vid nyexploaterade miljöer för hantering av dagvatten. Detta genomfördes genom att lyfta kunskaper för att möta dagens och framtidens behov av fördröjning samt rening av dagvatten. För att identifiera lämpliga hållbara åtgärdsförslag undersöks flera olika faktorer som påverkar val av anläggning. Detta med betoning på kostnader och kapacitet. Frågeställningarna för denna studie besvaras genom intervjuer med yrkesverksamma roller inom bygg- och anläggningsbranschen. Detta genomfördes för att skapa en djupare förståelse för utformningen, kostnader och kapacitet. Frågorna till intervjun var baserade på den litteraturstudie som hade genomförts innan intervjuerna. Litteraturstudien lade grunden till den teoridel som intervjufrågorna var baserade på. För att identifiera faktorer som påverkar kostnader och kapacitet vid val av anläggning fanns det med frågeställningar kring detta i intervjun, vilket respondenterna fick besvara vad olika anläggningar kostar på en skala mellan 1-10. Studiens resultat pekar på att åtgärdsförslag som ska vara hållbara för hantering av dagvatten, bör vara blågrön infrastruktur. Exempelvis kan detta vara diken, permeabla anläggningar och dagvattendammar. Allt som efterliknar LOD-principen som innebär att hantera dagvattnet lokalt där det uppstår. Utformningen ska ske enligt standarder, vilket påvisas av att dagens och framtidens behov vid olika typer av flöden ska kunna hanteras. Olika faktorer påverkar val av anläggning där områdets förutsättningar, avrinningsområdets storlek, befintliga anläggningar eller infrastruktur, krav, riktlinjer, regler och flexibilitet utgör att alla projekt är unika där dessa parametrar behöver tas i beaktning. Slutligen, faktorerna kostnader och kapacitet kommer att påverka varandra, men det får kosta vad det kosta vill för att det primära målet för sociala, ekonomiska och ekologiska aspekter kommer alltid först.