Thesis (M.A.)--Ohio University, August, 2002. / Title from PDF t.p. Includes bibliographical references (leaves 70-75)

Rapid population growth and urbanization in semi-arid and arid regions has led to alterations in the water, carbon (C), and nitrogen (N) cycles (Gallo et al. 2014), prompting demands for mitigation strategies. Green Infrastructure (GI) is one of the methods used in urban storm water mitigation that delays and attenuates stormwater runoff by storing water in vegetated depressions. In the Southwest these depressions, also called bioswales, have the potential to act as biogeochemical hot spots, encouraging nutrient cycling, infiltration, plant growth, and microbial activity (McClain et al. 2003). An influx of water to GI initiates a combination of physical and microbial processes that result in increased CO2 efflux and N mineralization known as the Birch Effect (Birch, 1958). This study examines GI in Tucson, AZ through inducing an artificial precipitation regime and determining how soil properties, GI design, and biogeochemical characteristics influence the response. In natural systems it has been shown that soil moisture, soil properties, organic matter, length of dry period, nutrients such as carbon and nitrogen, and microbial biomass influence soil respiration and nitrogen mineralization (Borken and Matzner 2009). The purpose of this study is to determine the role that the Birch Effect plays in urban stormwater GI. Additionally we seek to determine how soil and nutrient properties and precipitation regime affect the amplitude of the response. It was found that soils from GI features tend to have higher concentrations of organic matter, total carbon, and total nitrogen, as well as higher water holding capacity and lower bulk density. It was also shown that soils originating from GI features tend to illicit a greater CO2 flux upon rewetting than soils from adjacent areas. The linear relationships found between % clay, pH, bulk density, WHC, SOM, TC, and TN suggest that the reason for the greater response to wetting is due to the altered physiochemical composition. The results of this study can be utilized to increase microbial activity and remediation in urban GI features. This fits into the larger goal of GI to help mitigate many of the issues associated with Urban Stream Syndrome (USS) such as flashier hydrography response, increased nutrient and contaminant concentrations, increased erosion, altered channel morphology and reduced biodiversity (Meyers et al. 2005).

Urbanization has considerably altered natural hydrology of urban watersheds by increasing runoff volume, producing higher and faster peak flows, and reducing water quality. Efforts to minimize or avoid these impacts, for example by implementing low impact development (LID) practices, are gaining momentum. Designing effective and economical stormwater management practices at a watershed scale is challenging; LIDs are commonly designed at site scales, considering local hydrologic conditions (i.e., one LID at a time). A number of empirical studies have documented hydrologic and water quality improvements achieved by LIDs. However, watershed scale effectiveness of LIDs has not been well studied. Considering cost, effort, and practicality, computer modeling is the only viable approach to assess LID performance at a watershed scale. As such, the United States Environmental Protection Agency’s Stormwater Management Model (SWMM) was selected for this study. It is well recognized that model predictions are plagued by uncertainties that arise from the lack of quality data and inadequacy of the model to accurately simulate the watershed. To scrutinize sensitivity of prediction accuracies to spatial resolution, four SWMM models of different spatial detail were developed for the Ballona Creek watershed, a highly urbanized watershed in the Los Angeles Basin, as a case study. Detailed uncertainty analyses were carried out for each model to quantify their prediction uncertainties and to examine if a detailed model improves prediction accuracy. Results show that there is a limit to the prediction accuracy achieved by using detailed models. Three of the four models (i.e., all but the least detailed model) produced comparable prediction accuracy. This implies that devoting substantial resources on collecting very detailed data and building fine resolution watershed models may not be necessary, as models of moderate detail could suffice. If confirmed using other urban watersheds, this result could benefit stormwater managers and modelers. All four SWMM models were then used to evaluate hydrologic effectiveness of implementing bioretention cells at a watershed scale. Event based analyses, 1-year, 2-year, 5-year and 10-year storms of 24-hours were considered, as well as data from October 2005 to March 2010 for a continuous simulation. The runoff volume reductions achieved by implementing bioretention cells were not substantial for the event storms. For the continuous simulation analysis, however, about twenty percent reductions in runoff volume were predicted. These results are in-line with previous studies that have reported ineffectiveness of LIDs to reduce runoff volume and peak for less frequent but high intensity storm events.

Yoga adherents claim many benefits of the practice, including promotion of bone health and prevention of osteoporosis. However, few, if any, studies have investigated whether yoga enhances bone mineral density. Furthermore, none have identified force generation in yoga. The purpose of this study is to collect ground reaction force (GRF) data on a variety of common hatha yoga postures that would be practiced in fitness centers or private studios. Twelve female and eight male volunteers performed a sequence of 28 common hatha yoga postures while ground reaction force data were collected with an AMTI strain-gauge force plate. The sequence was repeated six times. Four variables were studied: the maximum vertical GRF, the mean vertical GRF, the maximum resultant GRF, and the mean resultant GRF. Univariate analysis was used to identify mean values and standard deviations for each of the four variables. Multivariate analysis revealed some variation due to gender but none due to age or weight. Means were similar across all poses and subjects, and standard deviations were small. This unique yoga sequence produced low impact forces in both upper and lower extremities. Further research is warranted to determine whether these forces are sufficient to promote osteogenesis or maintain current bone health in yoga practitioners.

Degradation of the nation's waters continues to be a problem and urban runoff is a large contributor to it. New stormwater management policies stress the importance of using stormwater control practices that reduce the quantity and improve the quality of stormwater runoff. The new approaches tend to emphasize small-scale, on-site practices over large scale. Yet to achieve water quality benefits, stormwater control practices must be maintained over time. Maintenance costs of these facilities, however, are poorly understood. A case study of five municipalities around the United States is used to estimate inspection and enforcement costs for each case site. Maintenance activities and costs were collected at the case sites for the following stormwater controls: dry ponds, wet ponds, wetlands, bioretention facilities, sand filters, and infiltration trenches. Cost estimates indicate that inspection and enforcement is not influenced by type. Maintenance cost estimates change depending on the BMP type. Estimated annual post-construction costs applied to a hypothetical 1,000-acre indicate that moving from large-scale to small-scale stormwater controls has a large impact in terms of financial obligation. / Ph. D.

This study examines the use of bioretention as a strategy to reduce the thermal impact associated with urban stormwater runoff in developing cold water stream watersheds. Temperature and flow data were collected during ten controlled trials at a bioretention facility located in Blacksburg, Virginia. It was determined that bioretention has the ability to reduce the temperature of thermally charged stormwater runoff received from an asphalt surface. Significant reductions in average and peak temperatures were observed. However, this facility was unable to consistently reduce the temperature below the threshold for trout health. The ability of bioretention to reduce runoff flow rates could also serve to reduce the thermal impact. Based on these results it was concluded that bioretention appears to have the capability to reduce the thermal impact of urban stormwater runoff on cold water stream ecosystems. / Master of Science

Low Impact Development (LID) is gaining popularity as a solution to erosion, flooding, and water quality problems that stormwater ponds partially address. LID analysis takes a spatially lumped approach, based on maintaining the predevelopment Curve Number and time of concentration, precluding consideration of the spatial distribution of impervious areas and Integrated Management Practices (IMP's), runoff-runon processes, and the effects of land grading. Success is thus dependent on the accuracy of the assumption of watershed uniformity, applied to both land cover distribution and flow path length. Considering the cost of long-term paired watershed monitoring, continuous, spatially-distributed hydrologic modeling was judged a better method to compare the response of LID, forest, and conventional development. Review of available models revealed EPA-SWMM 4.4H as the most applicable to the task. A 4.3-acre subwatershed of a local subdivision was adapted to LID using impervious surface disconnection, forest retention, and IMPs. SWMM was applied to the LID development at a fine spatial scale, yielding an 80-element SWMM model. The LID model was modified to reflect conventional development, with gutters, storm sewer, and detention. A predevelopment forest model was also developed. Two parameter sets were used, representing a range of assumptions characterized as favorable or unfavorable toward a particular development form. Modeled scenarios included favorable and unfavorable versions of Forest, LID, uncontrolled Conventional Development, and Conventional Development with Stormwater Management. SWMM was run in continuous mode using local rainfall data, and event mode using NRCS design storms. Runoff volumes, peak flows, and flow duration curves were compared. / Master of Science

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-28T12:52:56Z No. of bitstreams: 2 Tese - Patrícia Layne Alves - 2015.pdf: 6139087 bytes, checksum: 2d26cabd2939ffa1c0a67132b80a0490 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-28T12:54:31Z (GMT) No. of bitstreams: 2 Tese - Patrícia Layne Alves - 2015.pdf: 6139087 bytes, checksum: 2d26cabd2939ffa1c0a67132b80a0490 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-28T12:54:31Z (GMT). No. of bitstreams: 2 Tese - Patrícia Layne Alves - 2015.pdf: 6139087 bytes, checksum: 2d26cabd2939ffa1c0a67132b80a0490 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-04-16 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Problems related to water, in the urban environment, have drawn attention in the face of the problem caused by its lack and/or excess. Among this backdrop there is the tumultuous occupation of urban space that combined with the suppression of soil coverage and vegetation leads to the urban runoff higher volume, pollution and shorter time to peak discharge. In this context, the benefits of urban afforestation are present, which besides the aesthetic value added to space, set up physical barriers to stormwater, favoring its retention, storage and infiltration into the soil. This study aims to evaluate the capacity of rainfall interception treetops the some species, reduce the volume of urban runoff, slow the flow peaks, as well as to expand the attention span of an urban watershed. The research was field experiments with recurrent arboreal species in the urban afforestation of Uruaçu, Goiás, using pluviographs, trunk collectors and water level sensor. From the use of interception parameters determined in this study, computer simulations using the Storm Water Management Model Model (SWMM) were performed, starting from the proposition of scenarios with different types of territorial installment associated with the Low Impact Development practices (LID) and urban forestry. During the data collection period 2012/2013, the rainfall events had a median of accumulated rainfall of 16.7mm. During this period, the median values of interception were Mangifera indica - 8.0mm; Pachira aquatica - 7.4mm; Licania tomentosa - 7.2mm; and Caesalpinia peltophoroides - 4.8mm. The period of data collection relating to 2013/2014, the median precipitation of rainfall events were 20.7mm, and the median values for interception and stemflow were respectively: 5.7mm and 0.1mm for Mangifera indica; 4.5mm and 0.2mm for Licania tomentosa; and 3.8mm and 0.3mm for Tabebuia ochracea. The delay at the start of average rains caused by tree species was 3min. The presence of individual trees afforded a median delay in the peak time of 3 min, a reduction of the peak flow of 0.8 mm/min and runoff of 4.7mm/min. Through simulations with the scenario where the wooded urban planning aggregated all LID techniques employed in this study, it was possible to achieve a reduction in peak flows in 3.42m³ / s, compared to conventional design; allowing storage of a volume of water in 4470.59m³ local infiltration proposed structures; and delay the peak flows of up to 6 min. This thesis confirms the interference of the individual characteristics of the species in the rain interception capability by their canopies and reducing runoff, highlighting the need for careful definition of the species that make up the urban forestry; testifies the existence of variations in interceptions in relation to rainfall events and during their occurrence; as well as quantitative data points precipitate volume reduction and drained by the tree individual presence in urban areas. Their research shows that, alone, afforestation and LID techniques cause little reduction in volume and flow and little delay in time to peak flow, while combined contribute significantly to drainage. This study differs from the use of recording rain gauges and linígrados for the measurement of precipitation and runoff directly under the canopy of individual trees in an urban environment; and adds to SWMM the insertion of arboreal benefits in hydrological simulation. / Os transtornos relacionados à água, no ambiente urbano, têm merecido destaque diante da problemática causada pela sua falta e/ou excesso. Dentre este cenário, tem-se a ocupação desordenada do espaço urbano, que aliada à supressão da cobertura natural do solo e da vegetação acarretam ao escoamento urbano maior volume, poluição e menor tempo ao pico de vazão. Neste contexto, insere-se os benefícios da arborização urbana, que além do valor estético que agrega ao espaço, oferece barreiras físicas às águas pluviais, favorecendo a sua retenção, armazenamento e infiltração no solo. Este estudo se propõe a avaliar a capacidade de algumas espécies arbóreas em interceptar as águas de chuva pelas suas copas, reduzir o volume de escoamento superficial urbano, retardar os picos de vazão, bem como de ampliar o tempo de concentração de uma bacia hidrográfica urbana. A pesquisa teve experimentos de campo com espécies arbóreas recorrentes à arborização urbana de Uruaçu, Goiás, utilizando pluviógrafos, coletores de tronco e linígrafos. A partir do emprego dos parâmetros de interceptação determinados neste estudo, foram realizadas simulações computacionais com o uso do modelo Storm Water Management Model (SWMM), partindo da proposição de cenários com diferentes tipologias de parcelamento territorial associados às práticas de Low Impact Development (LID) e à arborização urbana. Durante o período de coleta de dados de 2012/2013, os eventos chuvosos tiveram mediana de 16.7mm de precipitação acumulada. Neste período, os valores medianos de interceptação foram: Mangifera indica – 8.0mm; Pachira aquatica - 7.4mm; Licania tomentosa – 7.2mm; e, Caesalpinia peltophoroides - 4.8mm. No período de coleta dados referente a 2013/2014, as precipitações medianas dos eventos chuvosos foram de 20.7mm, e os valores medianos para interceptação e escoamento pelo tronco, foram respectivamente: 5.7mm e 0.1mm para a Mangifera indica; 4.5mm e 0.2mm para a Licania tomentosa; e, 3.8mm e 0.3mm para a Tabebuia ochracea. O retardo mediano no início das chuvas ocasionado pelas espécies arbóreas foi de 3min. A presença dos indivíduos arbóreos propiciou, um atraso mediano no tempo ao pico de 3 minutos, uma redução do pico de vazão de 0.8 mm/min e do escoamento superficial de 4.7mm/min. Através de simulações, com o cenário em que o planejamento urbano arborizado agregava todas as técnicas de LID neste estudo empregadas, conseguiu-se atingir a redução das vazões de pico em 3.42m³/s, em relação ao projeto convencional; permitindo o armazenamento de um volume de água de 4470.59m³ nas estruturas de infiltração locais propostas; e, retardar os picos de vazão em até 6 min. Esta tese, confirma a interferência das características individuais das espécies na capacidade de interceptação de chuva por suas copas e na redução do escoamento superficial, ressaltando a necessidade de definição criteriosa das espécies que comporão a arborização urbana; atesta a existência de variações nas interceptações em relação aos eventos chuvosos e durante suas ocorrências; bem como, aponta dados quantitativos de redução de volume precipitado e escoado pela presença do indivíduo arbóreo no meio urbano. A pesquisa comprovou que, isoladamente, a arborização e as técnicas de LID causam pouca redução no volume e vazão e, pouco retardo no tempo ao pico do escoamento, enquanto que somadas contribuem de forma significativa à drenagem. O presente estudo se difere pela utilização de pluviógrafos e linígrados para a aferição de precipitações e escoamento superficial diretamente sob as copas de indivíduos arbóreos em ambiente urbano; e, agrega ao SWMM a inserção dos benefícios arbóreos na simulação hidrológica.

Over the past decades, climate change and urbanization have altered the regional hydro-environments, causing a series of stormwater management problems including urban flood and non-point pollution. Low impact development (LID) has been identified as a sustainable strategy for stormwater management. However, given the complex impacts of climate change and urbanization on hydro-environments, the performance of LID strategy under future changes remains largely unexplored. Accordingly, this research characterized the LID performance under changes in climate and urbanization. To provide an additional reference to sustainable stormwater management, the following specific topics were addressed: (1) Through hydraulic and water quality modeling, the LID performances of flood mitigation and pollution removal were systematically evaluated at the city scale. (2) Through uncertainty analysis, the impact of model parameter uncertainty on the LID performance was taken into account. (3) Through sensitivity analysis, the impact of LID technical parameters (e.g., surface features, soil textures) on the LID performance was quantified. (4) Through scenario analysis, the LID performances under different hydrological patterns were compared. (5) Through spatial analysis, the distribution of LID performance on different land-cover types was determined. (6) Through adopting general circulation model (GCM) projections, the LID performance under future climate scenarios with different representative concentration pathways (RCPs) was investigated. (7) Through adopting integrated assessment model (IAM) projections, the LID performance under future urbanization scenarios with different shared socioeconomic pathways (SSPs) was explored. (8) By coupling climate and urbanization projections with land-cover distribution, the spatiotemporal trends of LID performance in the future were characterized.:Table of Contents List of Abbreviations VII List of Peer-Reviewed Publications on the Ph.D. Topic IX List of Co-authored Peer-Reviewed Publications on the Ph.D. Topic X 1 General Introduction 1 1.1 Background 1 1.2 Objectives 3 1.3 Innovation and Contribution to the Knowledge 3 1.4 Outline of the Dissertation 4 1.5 References 5 2 Literature Review 9 2.1 Hydraulic and Water Quality Modeling 9 2.1.1 Hydraulic Model 9 2.1.2 Water Quality Model 10 2.2 Low Impact Development (LID) 10 2.2.1 LID Practice 10 2.2.2 LID Performance 11 2.3 Performance Evaluation 13 2.3.1 Scenario Analysis 13 2.3.2 Spatial Analysis 13 2.3.3 Uncertainty Analysis 14 2.3.4 Sensitivity Analysis 14 2.4 Future Changes in Climate and Urbanization 15 2.4.1 Climate Change 15 2.4.2 Future Urbanization 16 2.5 References 17 3 Impact of Technical Factors on LID Performance 27 3.1 Introduction 28 3.2 Methods 30 3.2.1 Study Area 30 3.2.2 Model Description 31 3.2.2.1 Model Theory 31 3.2.2.2 Model Construction 31 3.2.2.3 Model Calibration and Validation 32 3.2.2.4 Model Uncertainty Analysis by GLUE Method 34 3.2.3 Hydrological Pattern Design 35 3.2.4 LID Strategy Design 35 3.2.4.1 Implementation of LID Practices 35 3.2.4.2 Sensitivity Analysis by Sobol’s Method 36 3.2.5 Correlation Analysis Using a Self-Organizing Map 37 3.2.6 Description of the RDS Load Components 37 3.3 Results 38 3.3.1 RDS Migration and Distribution in Baseline Strategy 38 3.3.1.1 RDS Migration under Hydrological Scenarios 38 3.3.1.2 RDS Distribution on Land-Cover Types 39 3.3.2 RDS Removal in LID Strategies 40 3.3.2.1 RDS Removal by LID Strategies 40 3.3.2.2 Spatial Distribution of the RDS Removal 42 3.3.2.3 LID Parameter Sensitivity Analysis Result 43 3.4 Discussion 45 3.4.1 Factors Influencing RDS Migration in the Baseline Strategy 45 3.4.2 RDS Removal Performance by LID Strategy 46 3.5 Conclusions 47 3.6 References 47 4 Impact of Hydro-Environmental Factors on LID Performance 53 4.1 Introduction 54 4.2 Methods 56 4.2.1 Study Area 56 4.2.2 Modeling Approach 56 4.2.2.1 Model Theory 56 4.2.2.2 Model Construction 56 4.2.2.3 Model Calibration and Validation 57 4.2.2.4 Model Uncertainty Analysis 57 4.2.3 LID Performance Analysis 58 4.2.3.1 LID Practice Implementation 58 4.2.3.2 LID Performance Evaluation 58 4.2.4 Hydrological Pattern Analysis 59 4.2.4.1 Scenario of ADP Length 59 4.2.4.2 Scenario of Rainfall Magnitude 59 4.2.4.3 Scenario of Long-Term pre-Simulation 60 4.2.5 Sensitivity Analysis of Hydrological Scenarios 60 4.3 Results 61 4.3.1 LID Performance under Different ADP Lengths 61 4.3.2 LID Performance under Different Rainfall Magnitudes 62 4.3.3 Spatial Distribution of LID Performance 63 4.3.4 Sensitivities of LID Performance to ADP Length and Rainfall Magnitude 66 4.4 Discussion 68 4.4.1 Impact of ADP Length and Rainfall Magnitude on LID Performance 68 4.4.2 Spatial Heterogeneity of LID Performance 68 4.4.3 Research Implications 69 4.5 Conclusions 70 4.6 References 71 5 Impact of Future Climate Patterns on LID Performance 77 5.1 Introduction 78 5.2 Methods 80 5.2.1 Study Area 80 5.2.2 Hydraulic and Water Quality Model 80 5.2.2.1 Model Development 80 5.2.2.2 Model Calibration and Validation 81 5.2.3 Climate Change Scenario Analysis 81 5.2.3.1 GCM Evaluation 81 5.2.3.2 Greenhouse Gas (GHG) Concentration Scenario 82 5.2.3.3 GCM Downscaling 83 5.2.4 LID Performance Analysis 83 5.2.4.1 Implementation of LID Practices 83 5.2.4.2 Evaluation of LID Performance 84 5.2.4.3 Sensitivity Analysis on LID Performance 86 5.3 Results 86 5.3.1 Hydrological Characteristics under Future Climate Scenarios 86 5.3.2 LID Performance under Future Climate Scenarios 87 5.3.2.1 LID Short-Term Performance 87 5.3.2.2 LID Long-Term Performance 90 5.3.3 Impact of ADP Length and Rainfall Magnitude on LID Performance 92 5.3.3.1 LID Performance Uncertainty 92 5.3.3.2 Spatial Distribution of LID Performance 93 5.3.3.3 Sensitivity of LID Performance to Climate Change 95 5.4 Discussion 97 5.4.1 LID Performance in Short-Term Extremes and Long-Term Events 97 5.4.2 Impact of Climate Change on LID Performance 97 5.4.3 Research Implications 99 5.5 Conclusions 100 5.6 References 100 6 Impact of Climate and Urbanization Changes on LID Perfor-mance 109 6.1 Introduction 110 6.2 Methods 112 6.2.1 Study Area 112 6.2.2 Modeling Approach 112 6.2.2.1 Model Development 112 6.2.2.2 Model Calibration and Validation 113 6.2.3 Future Scenario Derivation 113 6.2.3.1 Climate Change Scenario 113 6.2.3.2 Urbanization Scenario 115 6.2.4 Flood Exposure Assessment 115 6.2.5 Implementation and Evaluation of LID Strategy 117 6.2.5.1 Implementation Scheme of LID Strategy 117 6.2.5.2 Performance Evaluation of LID Strategy 117 6.3 Results 118 6.3.1 Flood Exposure in Baseline and Future Scenarios 118 6.3.1.1 Hydrological Change in Future Climate Scenarios 118 6.3.1.2 Catchment Change in Future Urbanization Scenarios 118 6.3.1.3 Population and GDP Exposures to Flood in Future 121 6.3.2 Flood Exposure with Consideration of LID Strategy 123 6.3.2.1 Runoff Mitigation Performance of LID Strategy 123 6.3.2.2 Peak Mitigation Performance of LID Strategy 124 6.3.2.3 Population and GDP Exposures to Flood under LID Strategy 125 6.4 Discussion 126 6.4.1 Climate Change and Urbanization Exacerbated Flood Exposure Risk 126 6.4.2 LID Strategy Mitigated Flood Exposure Risk 126 6.5 Conclusions 127 6.6 References 127 7 Discussion and General Conclusions 133 7.1 Stormwater Management Performance of LID Strategy 133 7.2 Impact of Influencing Factors on LID Performance 134 7.3 LID Performance under Future Changes 135 7.4 Research Implications 136 7.5 References 137 8 Outlook of Future Research 139 8.1 Optimization of LID Performance 139 8.2 Cross-regional Study on Future Changes 139 8.3 Macro-scale Flood Risk Management 140 8.4 References 141 9 Appendices 143 9.1 Appendix for Chapter 3 143 9.1.1 The Determination of the GLUE Criteria 143 9.1.2 Model Uncertainty Analysis 143 9.1.3 The LID Installation Location 144 9.1.4 Figures 145 9.1.5 Tables 147 9.2 Appendix for Chapter 4 153 9.2.1 Scenario of Long-term pre-Simulation 153 9.2.2 Figures 153 9.2.3 Tables 158 9.3 Appendix for Chapter 5 164 9.3.1 Tables 164 9.4 Appendix for Chapter 6 169 9.4.1 Figures 169 9.4.2 Tables 170 9.5 Data Source 177 9.6 References 178

Sustainable Built Environments Senior Capstone Project / During Tucson rainstorms, many roads and neighborhoods experience high levels of flooding on the city’s street networks. This phenomenon creates unsafe road conditions, damage to the road infrastructure, and excessive urban stormwater runoff that is potentially polluted. The vast quantities of impervious surfaces in the urban landscape impede the rainwater’s ability to infiltrate the ground, thus resulting in increased volumes of runoff during a rainstorm. Stormwater management is used by municipalities and communities to address the previously mentioned adverse impacts of stormwater runoff. Various techniques and strategies used in stormwater management include, low impact development (LID), green infrastructure, and better site design (BSD) strategies implemented during design stages to reduce stormwater runoff levels. In addition, local governments can establish stormwater utilities and policies in order to help address and better manage the issue of stormwater runoff within urban areas. The primary research questions of this study will include: What are the most effective best management practices and techniques to address urban runoff? What combination of best management practices and government policies will be the more effective in addressing Tucson’s urban runoff problem? Accordingly, this study will examine a variety of policies and techniques to address stormwater runoff, and then, based on this information, provide a suggestion of the best practices and techniques that may be feasible for implementation in Tucson.