The Ipswich River watershed has experienced increasing urbanization in recent years. The river, which supplies water to over 300,000 residents (twice the watershed’s population), was considered one of the 10 Most Endangered Rivers in the U.S. in 2003 due to seasonal low-flow and no-flow events. Seasonal outdoor water restrictions have curbed residential demand; however, impervious surfaces and municipal sewer systems direct much of the runoff outside the watershed. Low-impact development (LID) practices, specifically those that infiltrate runoff, have the potential to keep more water in the watershed, and increase baseflows in the river. This study seeks to ascertain the barriers and motivations that exist to LID adoption. A paper survey including Likert-scale questions and a photo preference component was sent to 1,000 homeowners in the watershed. Analysis of responses employed factor analysis and means comparisons to compare responses between concerned homeowners (those who belonged to the local watershed association) and randomly-selected homeowners. Income and educational attainment were significant variables in both aesthetic preferences and willingness to adopt LID practices. Perceived cost of landscape changes and concern about disease-carrying pests also surfaced as barriers to residential adoption. The findings emphasize alternate strategies for land use planners, landscape professionals and environmental organizations to promote behavioral changes in the way residential landscapes are managed, and policies municipalities could adopt to implement more widespread use of LID practices. More widespread understanding and appreciation of the multiple benefits of rain LID landscapes could also serve all three groups.

With over half of the world’s population living in urban settlements and an ongoing urbanization, cities today offer a unique opportunity to tackle climate change. Emissions of greenhouse gases derive from all products and services used, and in Sweden the average inhabitant emit 7 tons of greenhouse gases in carbon dioxide equivalents every year from privately acquired products and services, calculated from a consumption perspective. Long-term climate goals, and international climate agreements sets a limit of 1-2 tons. Lifestyle changes are important to achieve sustainable development, but planning practices today generally do not try to influence citizens’ consumption, and is presumed cannot affect inhabitants’ consumption of food, clothes, electronics, furniture, etc.  This thesis investigates how planning and the built environment can practically encourage more sustainable consumption patterns, and which of these practices would be suitable to implement in the current sustainability project of Norra Kymlinge. The study concludes that sustainable consumption patterns could be encouraged in Norra Kymlinge through: collaborative living, sharing infrastructure, green leases, food production, personal measurement, and semi self-built apartments. For future research, more quantitative studies on the topic are suggested.

Urban stormwater runoff is both an environmental threat and a valuable water resource. This dissertation explores the use of two stormwater management strategies, namely green stormwater infrastructure and stormwater real-time control (RTC), for capturing and treating urban stormwater runoff. Chapter 2 focuses on clean bed filtration theory and its application to fecal indicator bacteria removal in experimental laboratory-scale biofilters. This analysis is a significant step forward in our understanding of how physicochemical theories can be melded with hydrology, engineering design, and ecology to improve the water quality benefits of green infrastructure. Chapter 3 focuses on the novel application of unsteady transit time distribution (TTD) theory to solute transport in a field-scale biofilter. TTD theory closely reproduces experimental bromide breakthrough concentrations, provided that lateral exchange with the surrounding soil is accounted for. TTD theory also provides insight into how changing distributions of water age in biofilter storage and outflow affect key stormwater management endpoints, such as biofilter pollutant treatment credit. Chapter 4 focuses on stormwater RTC and its potential for improving runoff capture and water supply in areas with Mediterranean climates. We find that the addition of RTC increases the percent of runoff captured, but does not increase the percent of water demand satisfied. Our results suggest that stormwater RTC systems need to be implemented in conjunction with context-specific solutions (such as spreading basins for groundwater recharge) to reliably augment urban water supply in areas with uneven precipitation. Through a combination of modeling and experimental studies at a range of scales, this dissertation lays the foundation for future integration of TTD theory with RTC to improve regional stormwater management. / Doctor of Philosophy / Urban stormwater runoff contains a variety of pollutants. Conventional storm drain systems are designed to move stormwater as quickly as possible away from cities, delivering polluted runoff to local streams, rivers, and the coastal ocean – and discarding a valuable freshwater resource. By contrast, green stormwater infrastructure captures and retains stormwater as close as possible to where the rain falls. Green stormwater infrastructure can also help remove pollutants from stormwater through physical, chemical, and biological treatment processes. This dissertation describes two modeling approaches for understanding and predicting pollutant removal processes in green stormwater infrastructure (Chapters 2 and 3). Chapter 4 explores the implementation of smart stormwater systems, which use automated controllers and sensors to adaptively address stormwater management challenges. Through a combination of modeling and experimental studies at a range of scales, this dissertation lays the foundation for future improvements to regional stormwater management.

Cities worldwide are facing problems to mitigate the impact of urban stormwater runoff caused by the increasing occurrence of heavy rainfall events and urban re-densification. This study presents a new approach for estimating the potential of the Management of Urban STormwater at Block-level (MUST-B) by decentralized blue-green infrastructures here called low-impact developments (LIDs) for already existing urban environments. The MUST-B method was applied to a study area in the northern part of the City of Leipzig, Germany. The Study areas was divided into blocks smallest functional units and considering two different soil permeability and three different rainfall events, seven scenarios have been developed: current situation, surface infiltration, swale infiltration, trench infiltration, trough-trench infiltration, and three different combinations of extensive roof greening, trough-trench infiltration, and shaft infiltration. The LIDs have been simulated and their maximum retention/infiltration potential and the required area have been estimated together with a cost calculation. The results showed that even stormwater of a 100 year rainfall event can be fully retained and infiltrated within the blocks on a soil with low permeability (kf = 10−6 m/s). The cost and the required area for the LIDs differed depending on the scenario and responded to the soil permeability and rainfall events. It is shown that the MUST-B method allows a simple down- and up-scaling process for different urban settings and facilitates decision making for implementing decentralized blue-green-infrastructure that retain, store, and infiltrate stormwater at block level.

Over the past decades, the fast-changing global climate poses a significant challenge to many cities around the world to embrace resilience concepts, whereby a safe-to-fail planning approach replaces traditional fail-safe practices. The change in perspectives has seen an increase in climate-adapted infrastructural projects being integrated with the new urban planning agendas across the world. The investigation conducted was designed to understand the process of how resilience concepts travel between different cities, by investigating the actors who move policy knowledge, their roles in it, as well as the knowledge transfer process mechanism that is responsible for the movement of such policies. The investigation took advantage of a scoping study technique to answer the research questions, using mostly secondary data and an interview to verify the secondary sources. The findings and the discussion provided insights on who is involved in resilience policies and how these policies are transferred from one place to another. The investigation uncovered the influence policy mobilizers has on the movement of policy knowledge, as well as how the mobilization of policy knowledge can both be beneficial or detrimental, depending on the way it was moved or implemented. / Under de senaste decennierna utgör det snabba föränderliga globala klimatet en betydande utmaning för många städer runt om i världen med att anamma motståndskraftskoncept, där en planeringsstrategi med säkerhet att misslyckas ersätter traditionella felsäkra metoder. Förändringen i perspektiv har ökat klimatanpassade infrastrukturprojekten som integrerats med nya stadsplaneringsagendorna över hela världen. Studien genomfördes för att få en förståelse av hur motståndskraftskonceptet färdas mellan olika städer och detta genomfördes genom att undersöka de aktörer som förflyttar politisk kunskap och deras roller i den samt den kunskapsöverföringsmekanism som är ansvarig för rörelsen av sådan politik. Studien utnyttjade en scoping-studieteknik för att få svar på forskningsfrågorna, med mestadels sekundär data och en intervju för att verifiera sekundärkällorna. Resultaten och diskussionen gav insikter om vem som är inblandad i motståndskraft och hur policy överförs från en plats till en annan. Studien avslöjade även inflytande av politiskt mobilisering och kunskap som både kan vara fördelaktig eller skadlig beroende på hur den flyttades eller genomfördes.

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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.

This thesis investigates the effectiveness of Low Impact Development Infrastructure (LIDI) and Green Infrastructure (GI) in reducing flooding resulting from heavy rainfall events and sea-level rise, and in improving stormwater quality in the City of Miami Beach (CMB). InfoSWMM was used to simulate the 5, 10, and 100-year, 24-hour storm events, total suspended solids (TSS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) loadings, and in evaluating the potential of selected LIDI and GI solutions in North Shore neighborhood. Post-development results revealed a decrease of 48%, 46%, and 39% in runoff, a decrease of 57%, 60%, and 62% in TSS, a decrease of 82%, 82%, and 84% in BOD, and a decrease of 69%, 69%, and 70% in COD loadings. SWMM 5.1 was also used to simulate the king tide effect in a cross section in Indian Creek Drive. The proposed design simulations successfully demonstrated the potential to control flooding, showing that innovative technologies offer the city opportunities to cope with climate impacts. This study should be most helpful to the CMB to support its management of flooding under any adaptation scenarios that may possibly result from climate changes. Flooding could be again caused as a result of changes in inland flooding from precipitation patterns or from sea-level rise or both.

The purpose of this study is to determine if Low Impact Development (LID) can effectively mitigate flooding under projected climate scenarios. LID relies on runoff management measures that seek to control rainwater volume at the source by reducing imperviousness and retaining, infiltrating and reusing rainwater. An event-driven hydrologic/hydraulic model was developed to simulate how climate change, land use and LID scenarios may affect runoff response in the Bowker Creek watershed, a 10km2 urbanized catchment located in the area of greater Victoria, British Columbia, Canada. The first part of the study examined flood impacts for the 2050s (2040-2069) following the A2 emissions scenario. For the 24-hour, 25-year local design storm, results show that projected changes in rainfall intensity may increase flood extents by 21% to 50%. When combined with continued urbanization flood extents may increase by 50% to 72%. The second part of the study identified potential locations for three LID treatments (green roofs, rain gardens and top soil amendments) and simulated their effect on peak in-stream flow rates and flood volumes. Results indicate that full implementation of modeled LID treatments can alleviate the additional flooding that is associated with the median climate change projection for the 5-year, 10-year and 25-year rainfall events. For the projected 100-year event, the volume of overland flood flows is expected to increase by 1%. This compares favourably to the estimated 29% increase without LID. In term of individual performance, rain gardens had the greatest hydrologic effect during more frequent rainfall events; green roofs had minimal effect on runoff for all modelled events; and top soil amendments had the greatest effect during the heaviest rainfall events. The cumulative performance of LID practices depends on several variables including design specifications, level of implementation, location and site conditions. Antecedent soil moisture has a considerable influence on LID performance. The dynamic nature of soil moisture means that at times LID could meet the mitigation target and at other times it may only partially satisfy it. Future research should run continuous simulations using an appropriately long rainfall record to establish the probabilities of meeting performance requirements. In general, simulations suggest that if future heavy rainfall events follow the median climate change projection, then LID can be used to maintain or reduce flood hazard for rainfall events up to the 25-year return period. This study demonstrates that in a smaller urban watershed, LID can play an important role in reducing the flood impacts associated with climate change. / Graduate