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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Visitor awareness of low-impact camping techniques in the wilderness area Isle Royale National Park, Michigan an investigation of possible affecting factors /

Milanowski, Shannon M. January 2002 (has links)
Thesis (M.A.)--Ohio University, August, 2002. / Title from PDF t.p. Includes bibliographical references (leaves 70-75)
12

Influence of Soil Physical and Chemical Properties on Soil Co2 Flux in Semi-Arid Green Stormwater Infrastructure

Rockhill, Tyler K., Rockhill, Tyler K. January 2017 (has links)
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).
13

Sensitivity of Stormwater Management Solutions to Spatial Scale

Barich, Jeffrey Michael 01 June 2014 (has links)
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.
14

Ground Reaction Forces Generated by Twenty-eight Common Hatha Yoga Postures

Wilcox, Sylvia Joan 16 March 2010 (has links) (PDF)
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.
15

Estimating Post-Construction Costs of a Changing Urban Stormwater Program

Licher, Monica Katherine 05 July 2016 (has links)
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.
16

Thermal Pollution Mitigation in Cold Water Stream Watersheds Using Bioretention

Long, Daniel Lewis 24 March 2011 (has links)
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
17

Hydrologic Evaluation of Low Impact Development Using a Continuous, Spatially-Distributed Model

Bosley II, Eugene Kern 27 August 2008 (has links)
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
18

Degrowing the Swedish Breakfast : Architecture for post-growth rural communities

Svahn, Nathalie January 2024 (has links)
The Swedish breakfast is an ordinary thing. It usually consists of a bowl of ‘filmjölk’, a sandwich with butter and cheese, and a cup of coffee with milk. This nostalgic composition is routinely consumed at kitchen tables around Sweden, every morning, before the daily commute to work. Most of us consume at least one of these dairy products on a daily basis without thinking about how they arrived at our kitchen table The commercialisation of the food industry in the 20th century led to a commodification of dairy products. Through heavy marketing, dairy producers, with the goal of increasing their own profit, were able to infiltrate Swedish homes and increase their dairy consumption. Milk went from being a small scale, domestically produced and consumed food, to receiving a political status as a part of ‘folkhemmet’. Consumption of dairy products was encouraged as a way of building the Swedish welfare state (Martiin, 2024, 227-230). The Swedish breakfast was commodified. Food and shelter are two of the most basic human needs, and are inevitably affecting all of our lives. However, the environmental implications of how food is produced, sold, and consumed, as well as the impact of our domestic lives can no longer be ignored. Global warming, deforestation, eutrophication, and biodiversity loss are only a few climatic emergencies that we are facing due to humanity surpassing planetary boundaries. The correlation between economic growth and climate change is today commonly declared, and decreasing production and consumption is becoming increasingly urgent to avoid an ecological collapse. Departing from the increasing urgency of the climate emergency, this thesis investigates the environmental impact of the commodification of the dairy industry from degrowth perspective. Nested in a Northern Swedish rural context, this paper speculates about how the Swedish breakfast can be re-localised through degrowth processes, and how this can contribute to producing alternative, degrowth housing structures in the rural area Tavelsjö. A housing structure which creates low impact domesticity and a post-growth rural community.
19

EVALUATING THE IMPACT OF LAND USE AND CLIMATE CHANGE ON REGIONAL HYDROLOGY BY UTILIZING LOW IMPACT DEVELOPMENT TECHNIQUES.

Banjara, Mandip 01 August 2024 (has links) (PDF)
Regional hydrology is experiencing significant changes due to a combination of land use and land cover (LULC) transformations and the growing impact of climate change. As cities expand into what were once agricultural or forested areas, the hydrological characteristics of watersheds undergo substantial shifts, influencing stream flow and flood volumes. To better understand these changes, this study integrates two complementary approaches. The first utilizes the Cellular Automata–Markov (CA–Markov) model to project LULC changes, predicting substantial urban growth from 11.6% of total area in 2021 to 34.1% by 2050 and 44.2% by 2080. This urbanization correlates with increased peak discharge and runoff volume for a 100-year return period storm event, with peak discharge rising by 5% and 6.8%, and runoff volume by 8% and 13.3% by 2050 and 2080, respectively. The second approach employs the North American Regional Climate Change Assessment Program (NARCCAP) climate model to project future storm depths, with extreme climate scenarios suggesting an increase of up to 104% in storm depths, leading to a 37.72% rise in peak discharge and an 88.73% rise in flooding volume. To mitigate these impacts, Low Impact Development (LID) techniques such as Permeable Pavement, Green Roofs, and Bio-Retention Cells were evaluated for their effectiveness in reducing climate change-induced flood risks. Using the validated Personal Computer Storm Water Management Model (PCSWMM) to simulate rainfall-runoff scenarios, the results indicated that Permeable Pavement could reduce peak discharge by up to 28.57%, with Green Roofs and Bio-Retention Cells reducing peak discharge by up to 19.93% and 14.25%, respectively. These findings underscore the importance of implementing sustainable water management practices as part of urban planning to address the dual challenges of LULC changes and climate change-induced flooding, providing a path toward more resilient urban environments.
20

Capacidade de interceptação pelas árvores e suas influências no escoamento superficial urbano / Capacity of interception by trees and influences on urban runoff

Alves, Patrícia Layne 16 April 2015 (has links)
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.

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