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

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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.

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.

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.

Houston's Fifth Ward neighborhood is one of the last remaining areas of the inner city to have not yet seen large-scale redevelopment. Situated just northeast of downtown, the neighborhood's population is predominantly low- to mid-income African Americans; demographics are similar today as they were during the neighborhood's prime, from the 1920s-60s, when the Fifth Ward was a cultural hub of Houston famous for its musical culture of zydeco and blues. The ward's rich history also has dark spots, however, specifically its longstanding reputation as a center of poverty and violent crime, and its physical vulnerability to damaging floods. Much of the neighborhood's built history is unpreserved and unprotected, at risk of being wiped off the map by both development interests and extreme weather events. By modernizing the city's approach to stormwater management and infrastructure and strengthening its historic preservation and emergency management practices, Houston could help preserve one of its oldest communities, while also decreasing flood volumes, improving air and water quality, saving money, and establishing a pattern of smart growth citywide. In addition, neighborhood level efforts to promote placemaking via preservation and sustainability efforts can help the Fifth Ward leverage the redevelopment process to change its reputation, ensuring a future for the community that respects its past. / text

Stormwater runoff is one of the leading causes of water quality impairment in the U.S. Bioretention systems are ecologically engineered to treat stormwater pollution and offer exciting opportunities to provide local climate change resiliency by reducing peak runoff rates, and retaining/detaining storm volumes, yet implementation is outpacing our understanding of the underlying physical, biological, and chemical mechanisms involved in pollutant removal. Further, we do not know how performance will be affected by increases in precipitation, which are projected to occur in the northeastern U.S. as a result of climate change, or if these systems could act as a source or sink for greenhouse gas emissions. This research examines the design, construction, and development of monitoring methods for bioretention research, using the University of Vermont (UVM) Bioretention Laboratory as a case study. In addition, this research evaluates mobilization patterns and pollutant loads from road surfaces during the "first flush" of runoff, or the earlier part of a storm event. Finally, this research analyzes the comparative pollutant removal performance of bioretention systems on a treatment by treatment basis. At the UVM Bioretention Laboratory, eight lined bioretention cells were constructed with monitoring infrastructure installed at the entrance and at the subterranean effluent. A conventional, sand and compost based, bioretention soil media was compared to a proprietary media engineered to remove phosphorus, called Sorbtive Media™, under simulated increases in precipitation. Two drought tolerant vegetation mixes, native to the northeast, were compared for sediment and nutrient retention. Each treatment was sampled for soil gas emissions to determine if it was a source or a sink. The monitoring infrastructure designs used in this research allowed for the effective characterization of pollutant mass loads entering and exiting bioretention. Cumulative mass loads from stormwater were found to be highest for total suspended solids, followed by total Kjeldahl nitrogen, nitrate, non-labile phosphorus and soluble reactive phosphorus, in descending order by mass. Total suspended solids, total Kjeldahl nitrogen, and non-labile phosphorus mass were well retained by all bioretention treatments. However, the compost amendment in the conventional soil media was found to release labile nitrogen and phosphorus, far surpassing the mass loads in stormwater. When compared with conventional media, Sorbtive Media™ was highly effective at removing labile phosphorus and was also found to enhance nitrate removal. Systems containing deep-rooted vegetation (Panicum virgatum) were found to be particularly effective at retaining both labile and non-labile constituents. Overall, none of the bioretention treatments were found to be a significant source of N2O and were small sinks for CH4 in most treatments.

Master of Landscape Architecture / Department of Landscape Architecture/Regional and Community Planning / Tim Keane / Climate change and declining ecological health of urban environments are global issues of growing concern. In order to mitigate these issues we must reduce Greenhouse Gas emissions and increase green infrastructure solutions. One way of doing this is through improving public transportation and decreasing parking areas. In this study, Manhattan, Kansas was used to illustrate how improvements to public transportation can reduce parking demand and to show how excess parking can be transformed into green space to improve the ecological health of the city. First a review of literature and case studies related to increasing ridership of public transportation, reducing parking demand, and calculating ecologic and economic benefits was done. Then ArcGIS was used to analyze the existing public transportation in Manhattan, Kansas. Improvements to the existing transit system were developed and potential increase in ridership was calculated. ArcGIS was then used to analyze existing parking in Manhattan, Kansas. Excess Parking was determined based on current parking demand and predicted transit ridership. A suitability study was then done in ArcGIS to determine which parking areas should be converted into green space. The suitability map assisted in choosing four specific parking areas to redesign in detail to incorporate additional green space and tree cover. It was estimated that improving Manhattan’s bus system could double its ridership. It was also estimated that with improved public transit and parking planning, 30% of Manhattan’s parking could be eliminated. Converting 30% of Manhattan’s parking into green space would decrease runoff and pollutants from parking lots. Ecological valuation methods were used to calculate the benefits of converting parking into green space. It was found that integrating green space into parking lots would decrease stormwater runoff, mitigate the heat island effect, store carbon, improve air quality and may have social benefits as well.

A urbanização acelerada das últimas décadas aliada à ocupação desordenada e intensa impermeabilização do solo, têm agravado as cheias nas cidades brasileiras. Na cidade de São Paulo, recentemente, os períodos chuvosos, entre os meses de outubro e março, de 2009-2010 e 2010-2011 foram especialmente relevantes, quando ocorreram precipitações intensas e de longa duração que causaram grandes inundações e alagamentos por toda a cidade. Outro agravante é a continuidade da utilização única e exclusivamente de técnicas clássicas com enfoque higienista para a solução dos problemas de drenagem urbana, como é o caso das canalizações dos córregos e rios. Diante dessa problemática surge uma nova abordagem do tema que envolve o manejo sustentável das águas pluviais por meio da utilização de um conjunto de medidas de controle da fonte, que podem ser integradas aos sistemas de drenagem existentes. Essas medidas se baseiam na retenção e infiltração das águas pluviais e na retenção de poluentes, reduzindo a probabilidade de inundações e contribuindo para a melhoria da qualidade da água dos sistemas hídricos urbanos. O objetivo deste estudo foi avaliar, por meio da modelagem matemática, o efeito que a implantação de medidas controle na fonte pode proporcionar no abatimento dos picos de cheia em áreas urbanas densamente ocupadas. Para tanto foi selecionada a bacia do córrego da Luz localizada no centro da cidade de São Paulo que apresenta altas taxas de impermeabilização do solo. As análises foram feitas com o PCSWMM, que é um sistema de suporte a decisão espacial desenvolvido pela CHI para o SWMM5 da EPA. Foram selecionadas medidas de controle na fonte que possam se adequar em locais onde a disponibilidade de espaço é pequena, como é o caso dos pavimentos permeáveis, telhados verdes e jardins de chuva. Os cenários analisados consideraram a situação atual sem implantação de medidas de controle e a implantação individual e combinada das medidas de controle na fonte. São avaliados eventos de precipitações, considerando diferentes períodos de retorno e durações de chuva e a porcentagem de área impermeável contribuinte para as medidas de controle. Uma análise geral dos resultados da modelagem permite apontar que o amortecimento dos picos de cheia foi verificado em todos os cenários, em maior ou menor intensidade, e o melhor desempenho no abatimento do pico de cheia foi verificado nos cenários que consideraram a implantação de pavimentos permeáveis. Os resultados da modelagem e os baixos custos de implantação dos pavimentos permeáveis sugerem que esta medida, dentre as três analisadas, é a que apresenta melhor custo-benefício. Contudo sabe-se que a implantação de pavimento asfáltico permeável em 100% da área disponível pode não ser viável. Logo a implantação conjunta com outras medidas de controle pode melhorar o desempenho de um sistema de controle de cheias. / The accelerated urban growth in the last decades associated with a disordered occupation and excessive impervious surfaces has worsened the floods in Brazilian cities. In the City of São Paulo, lately, the rainy season between October and March, in 2009-2010 and in 2010-2011, were especially relevant. There were intense and long-lasting rainfalls that caused flooding all over the city. Another aggravating factor is the single and exclusive use of traditional stormwater management methods for solving urban drainage problems, which is the case of stream and river canalizations. When faced with these problems, a new approach that involves the sustainable management of rainwater starts growing. These techniques include a set of low impact development practices that should be incorporated to the existing drainage systems. They are based on the detention and infiltration of stormwater, also the retention of pollutants. They also contribute to decreasing flood probability and to improving water quality of urban water systems. The goal is to evaluate, through a mathematical modeling, the low-impact development practices effect on reducing the peak runoff rates in highly urbanized areas. To this end, a subcatchment located in the center of São Paulo city, called Córrego da Luz, was chosen. This subcatchment has high rates of soil imperviousness. The analysis will be made with the PCSWMM, which is a spatial decision support system for the SWMM5 from EPA. The PCSWMM was developed by CHI. The low-impact development techniques selected for this study are permeable pavements, green roofs and rain gardens. These techniques can be implemented in places where space is no longer available. The scenarios must consider the current situation without the implementation of control measures, the individual and combined implementation of these practices. Various rainfall events were evaluated considering different durations. Also evaluated were the different percentages of impervious areas treated by low-impact development techniques. An overview of modeling results allows stating that the reduction of peak runoff was observed in all the scenarios, at greater or lower intensity. But the best performance was observed in scenarios that considered the implementation of permeable pavements. Modeling results and low-cost implementation of permeable pavements suggest that it is the most cost-effective measure, among the three analyzed. However, it is known that the implementation of permeable pavement in 100% of the available area may not be feasible. Hence, the combined implementation with other low-impact developments might improve the performance of a flood control system.