Vegetated roof technologies are increasingly being adopted as treatment measures to mitigate the effects of urban stormwater. A mass balance approach was used to assess the wet weather performance of a vegetated roof on the top of city hall in Waterloo, Ontario. Vegetated and control roof sections were instrumented to measure precipitation inputs, storage and outflow for 18 storm events from June to October, 2006. Concentrations of suspended solids (SS), total phosphorus (TP), soluble reactive phosphorus (SRP), copper (Cu), zinc (Zn), chromium (Cr) and cadmium (Cd) in precipitation and roof (vegetated and control) runoff were measured. A total of 155.6 mm of rain fell during the study period. The vegetated roof retained 64.5 mm (41.5%) of the total rainfall while the control roof retained ~ 5.1 mm (3.3 %). For individual rain events, the vegetated roof retained an average of 3.5 mm (47.6 %) while the control roof retained ~ 0.3 mm (4.7 %). Water retention varied with storm size, season and was influenced by wetting history. The vegetated roof retained 80.6 % of precipitation for light storm events (≤ 3.5 mm) and 34.9 % for large storm events (> 3.5 mm). The control roof retained 7.6 % light storm events and 3.7 % for large storm events. Water quality from the vegetated roof did not show significant improvement as only Zn concentrations in runoff from the vegetated roof were significantly lower than that measured in runoff from the control roof. Concentrations of SS, Cu, Cr and Cd in vegetated roof runoff were relative to concentrations in rainfall and control roof runoff and TP and SRP concentrations were significantly higher than that in rainfall or control roof runoff. Results gained from this study may assist people in planning and stormwater management by providing insight into the monitoring, development and application of new stormwater controls.

Population growth, urbanization and climate change threaten urban water systems. The rise of demands caused by growing urban areas and the potential decrease of water availability caused by the increase of frequency and severity of droughts challenge the continued well-being of society. Due to increasing environmental and financial constraints, water management paradigms have shifted from supply augmentation to demand management, and water conservation initiatives may efficiently decrease water demands to more sustainable levels. To provide reliable assessment of the efficiencies of different demand management strategies, new modeling techniques are needed that can simulate decentralized decisions of consumers and their interactions with the water system. An integrated simulation-optimization framework, based on the paradigm of Complex Adaptive Systems, is developed here to model dynamic interactions and adaptations within social, built, and natural components of urban water systems. The framework goes beyond tradition engineering simulations by incorporating decentralized, heterogeneous and autonomous agents, and by simulating dynamic feedback loops among modeling components. The framework uses modeling techniques including System Dynamics, Cellular Automata, and Agent-based Modeling to simulate housing and population growth, a land use change, residential water consumption, the hydrologic cycle, reservoir operation, and a policy/decision maker. This research demonstrates the applicability of the proposed framework through a series of studies applied to a water supply system of a large metropolitan region that is located in a semi-arid region and suffers recurrently from severe droughts. A set of adaptive demand management strategies, that apply contingency restrictions, land use planning, and water conservation technologies, such as rainwater harvesting systems, are evaluated. A multi-objective Evolutionary Algorithm is coupled with the CAS simulation framework to identify optimal strategies and explore conflicting objectives within a water system. The results demonstrate the benefits of adaptive management by updating management decisions to changing conditions. This research develops a new hydrologic sustainability metric, developed to quantify the stormwater impacts of urbanization. The Hydrologic Footprint Residence captures temporal and spatial hydrologic characteristics of a flood wave passing through a stream segment and is used to assess stormwater management scenarios, including Best Management Practices and Low Impact Development.

Impervious surfaces such as roads, sidewalks, and roofs increase the volume of runoff generated in a watershed. Traditional stormwater management techniques emphasize conveyance of runoff away from impervious surfaces in order to reduce flooding. Rain gardens are becoming popular as a different means to manage stormwater in such a way that runoff is captured and infiltrated onsite rather than conveyed offsite. A stormwater management system consisting of a rainwater harvest system, rain garden, and infiltration chamber was built at the Coca-Cola Refreshments USA, Inc. distribution center in Lexington, Kentucky during the fall of 2011. Precipitation, inflow, and water level were measured from May, 2012 to April, 2013 to evaluate the hydrologic performance of the rain garden. The rain garden had a high infiltrative capability and was able to capture and infiltrate 100% of the runoff generated during the study period. The results of the study were used to formulate recommendations for rain garden design and construction in central Kentucky.

Master of Science / Biological & Agricultural Engineering / Stacy L. Hutchinson / Increasing attentiveness to climate change and the dependence of human life on natural resources has spurred awareness about the detrimental impacts of human activity on the environment. Ecosystem services, or the benefits that humans derive from ecosystems, have changed more in the past 50 years than in any other comparable period in human history (Carpenter et al., 2009).The dilemma of managing the trade-off between immediate human needs and maintaining the ability of the Earth to provide ecosystem services is considered to be one of the largest challenges of this century (Foley et al., 2005). The ecosystem service concept aims maximize the provision of services across an entire ecosystem to achieve overall ecosystem health through land management, policy, and economic decisions. The intent of this research was to improve such decisions by increasing the understanding about the relationship between urban best management practices and freshwater provision, erosion regulation, and flood regulation ecosystem services. Fifty-six land management scenarios with varying densities of BMP application were simulated using the Stormwater Management Model (SWMM). The ecosystem services resulting from these land management scenarios were quantified using indices developed by Logsdon and Chaubey (2013). Results demonstrate that the application of bioretention cells improve both freshwater provision and erosion regulation services immediately downstream from the implementation site, and an increase in erosion regulation services was observed at the greater watershed scale. There was no change in the provision of freshwater, erosion regulation, or flood regulation services observed by the application of green roofs or rain barrels at either scale of analysis.

Urbanization increases runoff during storm events due to a reduction in vegetation and an increase in impervious surfaces, which limits the land's capacity to absorb and slow down water. This increase in runoff contributes to channel erosion. While extensive research exists on the hydrologic benefits of various types of stormwater control measures (SCMs), the relationship between urbanization, widespread SCM implementation, and channel stability in headwater streams remains less explored. Additionally, the impact of climate change (CC) on SCMs, with its growing focus due to improved global and regional CC models and data, is a critical area of study. However, most existing studies rely on simplified design storm analyses and unit-area runoff models, and there is a lack of comprehensive research evaluating the long-term, continuous hydrologic response of SCMs under future CC scenarios. This study presents an in-depth evaluation of the effectiveness of SCMs in maintaining channel stability in urbanized headwater streams, with a particular focus on the challenges posed by urbanization and CC. Conducted in a small catchment in Montgomery County, Maryland, USA, the study employs a sequential hierarchical modeling approach integrating the Storm Water Management Model (SWMM) with the Hydrologic Engineering Center's River Analysis System (HEC-RAS). First, the impact of a stormwater management system design following Maryland's Unified Stormwater Sizing Criteria (USSC) on channel stability was investigated. Simulation over 16 years (2004-2020) demonstrated that the majority of storm events were short in duration, with the greatest peak flows resulting from storm events with durations less than 24 hours. However, results indicated that despite the use of multiple SCMs, channel changes, including both degradation and aggradation up to 1.2 m, are likely over a period of 16 years. Study results indicate SCMs should be designed using continuous simulation models to simulate pre- and post-development sediment transport. Secondly, the impact of SCMs and CC on flow regime and channel stability was examined, challenging the previous simplified analyses. The findings highlight that future CC scenarios, characterized by decreased total rainfall but increased intensity, will likely shift watershed hydrology towards a flashier regime, exacerbating channel erosion. To address these shortcomings, a multicriteria design approach for SCMs is required, considering local sediment transport capacity and the complexities of urban catchments under changing climatic conditions. Lastly, evaluation of the impact of proposed stormwater regulations on channel stability using a novel three-step methodology revealed that SCM design goals focused on maintaining pre-development sediment transport or excess shear stress could reduce channel disturbance. Overall, this study illustrates the need for more nuanced and holistic approaches to stormwater management to ensure channel stability, especially in the face of the challenges posed by climatic changes. / Doctor of Philosophy / As cities grow, with more buildings and roads replacing green spaces, managing stormwater becomes a crucial challenge. Without enough soil and plants to absorb it, stormwater rushes over these hard surfaces, contributing to stream erosion. This urban scenario sets the stage for my research, which investigated effective ways to handle stormwater in cities to protect small, local streams. The focus of this study was to understand the performance of stormwater control measures (SCMs), which are engineered structures designed to manage this excessive runoff in urban environments. The key question is: Are SCMs effective, especially as we face the impacts of climate change? This research was conducted in a small watershed in Montgomery County, Maryland, using computer simulations to replicate water flow and stream conditions over a 16-year period. The findings reveal that, despite using SCMs, streams can still experience significant changes. This is especially true during intense, short-duration storms that can rapidly increase stream flow and cause channel erosion. With climate change, these problems may increase. Future weather patterns could lead to less frequent but more intense rainstorms. This study suggests that our approach to designing SCMs needs to be more sophisticated, taking into account not only the amount of water running into streams, but also the amount of coarse sediment moving during floods. In summary, this research highlights the need for comprehensive strategies in urban water management to ensure the stability and health of urban streams amidst the challenges of increasing urban development and climatic changes.

Cities are facing environmental crises like never before, with problems of excess water runoff, degraded water quality, air pollution, and energy use reaching critical levels. The development of urban areas and the built environment is the primary cause of these problems and the built environment needs to be a part of the solution. This design thesis project produces a prototype design for the Urban EcoHousing development on a city block in Alexandria, Virginia. Design goals for the project connect the "Ecological Services of the Urban Landscape" to the "Rights of the Urban EcoHousing Resident" to create livable green spaces that can serve ecological functions and give the residents spaces to use. A comparison study with a conventional housing development at the same location illustrates that ecohousing can meet the requirements of the conventional development while providing superior results for the residents and the environment. / Master of Landscape Architecture

Sustainable Built Environments Senior Capstone Project / Porous concrete pavements have been used in the eastern United States to effectively manage storm water when used as an alternative to impervious surfaces. This paper reviewed a wide body of available literature and research to examine their potential to reduce runoff at the University of Arizona. This study found that their unique structural properties enable them to infiltrate and detain large volumes of water in a stone sub-base below the slab, filtering out many street related contaminants without the need to install additional infrastructure. Porous concrete surfaces may support green development in the southwest where water is both a sensitive and valuable resource. However, long-term structural durability, clogging potential due to dust, and maintenance requirements have yet to be fully understood in this region. This paper then summarizes critical factors that affect the performance of porous concrete and proposes a framework for future study to be conducted by the University of Arizona in a way that would reduce runoff to major campus roads, contribute to a better understanding of sustainable storm water management in the southwest, and demonstrate leadership in environmental stewardship.

Partial-infiltration permeable pavement (PP) systems provide environmental benefits by increasing infiltration, attenuating storm flows and improving stormwater quality. This thesis focuses on the performance and operation of partial-infiltration PP systems over low permeability soil in Ontario. Three PP, AquaPave®, Eco-Optiloc® and Hydromedia® Pervious Concrete were monitored over two years and their performance was evaluated relative to an impermeable Asphalt control. Field data was collected from the Kortright PP pilot parking lot in Vaughan, Ontario. Through the use of restrictor valves on underdrains the PP systems were shown to provide substantial hydrologic benefits by eliminating stormwater outflow for rain events less than 7mm, reducing peak flows by 91% and reducing total stormwater volume by 43%. Stormwater quality was analyzed for winter and non-winter seasons. The PP were shown to greatly reduce the concentration and total loading of suspended solids, nutrients, hydrocarbons and most heavy metals. Some water quality data, such as pH, K, or Sr levels, indicate that the quality of PP effluent will change as the system ages. Study of PP sample boxes at the University of Guelph highlighted the role that construction materials have on effluent quality and showed that pollutants introduced by the pavement and aggregate are almost entirely in a dissolved form and decline very rapidly after a season of exposure to rainfall. Benefits to water quality were sustained during winter months. The partial-infiltration PP systems were shown to provide buffering of Na and Cl concentrations. Small and large-scale maintenance practices for PP systems were investigated. Small-sized equipment testing found that vacuum cleaning and pressure-washing have good potential to improve infiltration capacity. Testing of full-sized streetsweeping trucks demonstrated that permeability can be partially restored on PICP by suction-based sweeping. Vacuum-sweeping was beneficial on a PC pavement which had experienced large permeability losses. Results of this study indicate that partial-infiltration PP systems can be effective measures for maintaining or restoring infiltration functions on parking lots and other low volume traffic areas, even in areas with low permeability soils.

Centralized infrastructure (CI) is difficult to sustain with limited water and fossil fuel resources because CI withdraws 100% of water demand from the environment as an open-loop system and electricity is consumed to transport and treat water and wastewater while demand is increasing. Hybrid infrastructure (HI) is proposed to combine CI with decentralized alternatives such as low impact development (LID) technologies (i.e., xeriscaping, rain gardens, and rainwater harvesting) or greywater reclamation systems with membrane bioreactors (MBRs). Water, wastewater, and stormwater systems in the City of Atlanta (COA) were regarded as CI. HI was compared to CI using life cycle environmental impacts measured by water reuse index (WRI) and life cycle assessment (LCA) scores. WRI is a ratio of water withdrawal to sustainable water resources of wastewater (i.e., return flow) and stormwater discharge, which presents water stress level (e.g., 0.2 ~ 0.4: medium-high level). LCA score is determined as % of annual world average environmental damage per capita. As stormwater runoff, water demand, greywater generation, rainwater harvesting, etc. vary depending on land use and population density, feasibility of decentralized alternatives was evaluated in eleven residential communities. Five single-family residential communities were designated as between R-1 of 16 people/10 acres and R-5 of 169 people/10 acres and six multi-family residential communities were designated as between RG-1 of 148 people/10 acres and RG-6 of 5,808 people/10 acres. HI with LID technologies reduced WRI of COA that relies on CI from 0.45 to 0.12. HI reduced the LCA scores of CI with combined sewer system (CSS) by between 1% for RG-6 and 68% for R-1 and the LCA scores of CI with separate sewer system (SSS) by between 0% for RG-6 and 18% for R-1. As population density increases for the multi-family residential communities, harvested rainwater decreases and a small amount of water demand is satisfied. Consequently, it has a negligible impact on the LCA scores in RG-6. HI with greywater reclamation system reduced WRI of COA from 0.45 to 0.35. HI resulted in the LCA scores greater as compared to CI in the five single-family communities and RG-1, RG-2, and RG-3 because of the electricity consumption of small-scale MBR. However, the electricity consumption per kgal decreases with increasing MBR treatment capacity and the LCA scores were reduced by 5% for RG-4, 15% for RG-5, and 21% for RG-6. The MBR treatment capacity of RG-4 is 15.6 kgal/day.

Made available in DSpace on 2016-06-02T20:00:37Z (GMT). No. of bitstreams: 1 3523.pdf: 12073466 bytes, checksum: 878f935338c5beb08fa768751f31d082 (MD5) Previous issue date: 2009-02-15 / Urbans areas even biggens are becoming impermeabilized reducing the soil`s infiltration rate and increasing the velocity and volume of runoff, changing meaningly the hydrological cycle and causing floods. A set of techniques able to create hydrologically functional landscape can be found at Low Impact Development (LID) that works just similar to the natural, becoming possible the development of projects adapted to the natural topography, maintaining the yield of the lot and the local hydrological function; aiming at esthetics valorization and stormwater control management with low cost. This study makes use of this methodology since the beginning of the planning process, working at the some time with urban, environmental and hydrological aspects, intending to recuperate or even to keep the pre-development behavior of the area. To support the local hydrology, reduce sealing, keeping time to concentrate, to keep Fingerprinting, enhance infiltration, among others. It compares the predevelopment conditions, the conventional urbanization and that with LID techniques related to aspects mentioned to a specifc area at UFSCar Campus, São Paulo. This search revealed that is possible to have an urban planning using LID, with urban, environmental and hydrological advantages in the opposite to the conventional development systems, such as the increase of permeable areas, vegetation areas and the reduction of peak discharge and stormwater runoff. Low impact development makes these interventions in a simultaneous way just to re-establish the pre-existents conditions, and then to make use of integrated management`s practice. / Áreas urbanas cada vez maiores são impermeabilizadas, reduzindo a capacidade de infiltração do solo e acelerando a velocidade do escoamento superficial, alterando significativamente o ciclo hidrológico, e gerando inundações. Encontra-se no Desenvolvimento de Baixo Impacto (Low Impact Development, LID), um conjunto de técnicas capazes de criar paisagens hidrologicamente funcionais, com comportamento similar ao natural, facilitando o desenvolvimento de planos adaptados a topografia natural, mantendo o rendimento do lote e as funções hidrológicas do local; visando a valorização estética e a gestão de controle de águas pluviais menos custosas. Este trabalho utiliza-se desta metodologia desde o início do processo de planejamento, trabalhando concomitantemente os aspectos urbanísticos, ambientais e hidrológicos, de modo a recuperar e/ou manter o comportamento hidrológico de pré-ocupação da área. Os recursos são, manter hidrologia local, reduzir impermeabilização, manter o tempo de concentração, manter as digitais locais, potencializar infiltração, dentre outros. Comparam-se as condições de pré-ocupação, urbanização convencional e urbanização com técnicas de LID, quanto aos aspectos mencionados para uma área do Campus da UFSCar, em São Carlos/SP. Como resultado essa pesquisa revelou que o planejamento urbano utilizando-se de técnicas de baixo impacto é possível, apresentando vantagens urbanísticas, ambientais e hidrológicas sob os sistemas de desenvolvimento convencionais, tais como aumento das áreas permeáveis, das áreas de cobertura vegetal, redução da vazão de pico e do volume de escoamento superficial. O desenvolvimento de baixo impacto realiza estas intervenções de forma simultânea para restabelecer as condições pré-existentes, e só então, empregar práticas de gerenciamento integrado.