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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.
61

Multi-sensor platforms for the geophysical evaluation of sensitive archaeological landscapes : evaluation of, and improvement of, the MSP40 mobile sensor device for rapid multi-technique and low impact measurements on archaeological sites with vulnerable soil

Parkyn, Andrew Keith January 2012 (has links)
Mobile platforms for archaeological purposes have increased in use over the last 20 years with many of the developments coming from Continental Europe. Mobile platform developments have mainly focused on one type of instrumentation, offering multiple sensors, depths of detection or frequencies. This development of mobile platforms has focused on data acquisition rates but has not considered the physical impact on the soil. The Geoscan Research Mobile Sensor Platform (MSP40) was intended to improve survey efficiency and remain a lightweight system. The platform can collect two earth resistance configurations that show directional variation of the current flow through soil. Additional sensors were integrated on to the square frame of the hand-pulled cart to record simultaneous fluxgate gradiometer data and a microtopographic surveys. Ground based geophysical investigation will always have a physical impact on a site. The MSP40 is no exception but careful selection of wheel types and the lightweight frame limit the damage compared to many mobile arrays. The MSP40 has been tested on a number of different soils at various times of the year with encouraging results; however issues with overcoming the contact resistance of electrodes remain. The continuous collection rate and combination of techniques means a slight drop in data quality is inevitable. However the increased data density, multiple-sensors and improved rate of collection offset reductions in data quality. The research has shown that the MSP40 can perform low impact rapid site assessments on 'vulnerable' sites, whilst maximising the information gained from a single traverse.
62

Life-Cycle-Cost Analysis of using Low Impact Development Compared to Traditional Drainage Systems in Arizona: Using Value Engineering to Mitigate Urban Runoff

January 2019 (has links)
abstract: The rate of urbanization has been impacted by global economic growth. A strong economy results in more people moving to already crowded urban centers to take advantage of increased employment opportunities often resulting in sprawling of the urban area. More natural land resources are being exploited to accommodate these anthropogenic activities. Subsequently, numerous natural land resources such as green areas or porous soil, which are less flood-prone and more permeable are being converted into buildings, parking lots, roads and underground utilities that are less permeable to stormwater runoff from rain events. With the diminishing of the natural landscape that can drain stormwater during a rainfall event, urban underground drainage systems are being designed and built to tackle the excess runoff resulting from urbanization. However, the construction of a drainage system is expensive and usually involves massive land excavations and tremendous environmental disturbances. The option for constructing an underground drainage system is even more difficult in dense urban environments due to the complicated underground environments, creating a need for low footprint solutions. This need has led to emerging opportunities for low impact development (LID) methods or green infrastructures, which are viewed as an environmentally friendly alternative for dealing with stormwater runoff. LID mimics the pre-development environment to retain the stormwater runoff through infiltration, retention, detention and evaporation. Despite a significant amount of prior research having been conducted to analyze the performance of runoff volume reduction and peak flow decrement of various green infrastructures, little is known about the economic benefits of using LID practices. This dissertation fills the gap in the knowledge regarding the life-cycle-cost effectiveness of green infrastructure in current urban developments. This study’s two research objectives are: (1) Develop a life cycle cost calculation template to analyze the cost benefits of using LID compared to the traditional drainage system (2) Quantify the cost benefits based on the real-world construction projects A thorough literature review led to the data collection of the hydrological benefits of using LIDs in conjunction with overviewing three real-world construction projects to quantify the cost benefits of LIDs. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2019
63

Underground Stormwater Treatment Performance in Urban Coastal Catchments: Case Study of Baffle Boxes in the City of Tampa

Tsegay, Awet Eyob 21 June 2018 (has links)
In coastal urban regions, underground stormwater treatment units are suitable infrastructure options because they take less space where premium land is expensive. Even then, they should be accessible and ideally small enough to fit into existing stormwater networks. Since 2003, the City of Tampa and Florida’s Department of Transportation (FDOT) have installed 47 baffle boxes into the city’s stormwater pipe networks. Baffle boxes are underground stormwater treatment structures designed to capture sediments and floating debris. Since their deployment, many challenges regarding their practical sediment capturing performance was raised by the city. The objective of this research was to evaluate the effects of rainfall, land use, and maintenance on the sediment trapping efficiency of the baffle boxes and identify solutions to enhance their performance. This was addressed through site visits, sediment accumulation measurements and analysis of historical and field data. The results of these measurements and analysis were then compared to rainfall intensity, catchment characteristics, size and type of the units. During the preliminary site visits and sediment measurements it was observed that most of the units located in the south of Tampa were inundated by backflows from Tampa Bay. Survey information collected from inspection crew members also showed that resuspension of trapped sediments frequently occurs in these units. Concerning operation and maintenance (O&M), it was indicated that units mounted with screens are costly and difficult to clean-out. Additionally, it was found that 80% of the units have very small trap inlets and lack the baffle structures needed to slow down and settle sediments. Historical sediment measurements and O&M practices were analyzed to calculate the overall performance of the units. The analysis of the data determined the sediments captured, the resuspension rate, and yearly cost of maintenance for different types of baffle boxes. Rainfall intensity and land use and land cover (LULC) data for each catchment of the units was correlated to the performance of the units. The LULC data used impervious fraction and tree canopy area of the catchments to project sediment and leaf matter accumulation within the units. This research study found that total daily rainfall intensity is a good predictor of sediment accumulation. Cleanout crews can use this relationship to conduct their work efficiently and to promptly react to occurring rainfall events. Thus, the prediction of sediments accumulated from rainfall events and the coordination of clean-out trucks can optimize O&M practices. It was also determined that large-sized (24-40 in) units and those with three chambers (baffles) perform better at trapping sediments. Thus, installing baffles in units within the large-sized ones can enhance their performance. The study also found that baffle boxes mounted with screens can individually take up to eight hours to cleanup which makes them costly and difficult. This can be detrimental for municipalities to follow up on their O&M practices effectively. Therefore, to alleviate the clean out complexity and reduce maintenance expenditures complementary practices such as bag filters need to be explored and implemented for trials
64

Wet Weather Performance of an Extensive Vegetated Roof in Waterloo, Ontario

Vander Linden, William Kyle 19 September 2008 (has links)
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.
65

Wet Weather Performance of an Extensive Vegetated Roof in Waterloo, Ontario

Vander Linden, William Kyle 19 September 2008 (has links)
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.
66

Complex Adaptive Systems Simulation-Optimization Framework for Adaptive Urban Water Resources Management

Giacomoni, Marcio 2012 August 1900 (has links)
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.
67

HYDROLOGIC CHARACTERIZATION OF A RAIN GARDEN MITIGATING STORMWATER RUNOFF FROM A COMMERCIAL AREA

McMaine, John T 01 January 2013 (has links)
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.
68

Understanding the relationship between urban best management practices and ecosystem services

McDonough, Kelsey R. January 1900 (has links)
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.
69

Simulações de medidas compensatórias sustentáveis de drenagem: propostas em duas microbacias urbanas.

ALVES, Priscila Barros Ramalho. 26 July 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-07-26T15:07:48Z No. of bitstreams: 1 PRISCILA BARROS RAMALHO ALVES-DISSERTAÇÃO (PPGECA) 2017.pdf: 16298693 bytes, checksum: 353f5c91fe6e788569d5b7cca8ad3d5a (MD5) / Made available in DSpace on 2018-07-26T15:07:48Z (GMT). No. of bitstreams: 1 PRISCILA BARROS RAMALHO ALVES-DISSERTAÇÃO (PPGECA) 2017.pdf: 16298693 bytes, checksum: 353f5c91fe6e788569d5b7cca8ad3d5a (MD5) Previous issue date: 2017-02-22 / Capes / O processo de ocupação e crescimento dos centros urbanos comumente se dá a partir de um planejamento urbano empírico, atendendo a interesses de pequenos grupos sociais, e desarticulado de outros fatores que compõem uma cidade, como a bacia hidrográfica na qual o município está inserido, o relevo, o regime de chuvas da região, que interferem no sistema de drenagem de águas pluviais e podem apresentar riscos às pessoas que residem em áreas ocupadas indevidamente. O aumento desordenado de áreas impermeáveis nos centros urbanas causa impactos ao meio ambiente e danos à população, como alagamentos e inundações, caso não seja feito através de um processo de planejamento. O maior número de espaços impermeáveis gera altos escoamentos superficiais e levam os sistemas de drenagem, muitas vezes inadequados, ao seu limite de funcionamento. Nesse sentido, o presente trabalho simulou a aplicação de medidas compensatórias sustentáveis de baixo impacto, coberturas verdes, pavimentos permeáveis e jardins de chuva, em duas microbacias do município de Campina Grande – PB, a fim de mitigar os problemas no sistema de drenagem urbana do município. O software de simulação hidrológica utilizado foi o SWMM – Storm Water Management Model, com o objetivo de analisar a redução do escoamento superficial em bacias com alto e médio risco a alagamentos e inundações. As medidas compensatórias de drenagem urbana foram aplicadas em dois cenários: de uso atual observado no momento da pesquisa e com a impermeabilização máxima prevista em legislação. Os resultados indicaram desempenho satisfatório na implementação de todas as medidas, com reduções de até 100% de escoamento, porém, a eficiência na redução do volume de escoamento gerado varia de acordo com as áreas e critérios de aplicação. O uso das medidas propostas não é capaz de minimizar todos os impactos hidrológicos do uso e ocupação urbana mal planejados, mas os resultados deste estudo sugerem que as infraestruturas sustentáveis devem ser discutidas como um novo método de controle de inundação urbana, juntamente com o manejo e controle do uso e ocupação do solo. Espera-se que estes resultados contribuam para estudos futuros, a fim de que a cidade de Campina Grande, bem como outras cidades com problemas semelhantes, alcance um nível eficiente e sustentável de prestação dos serviços de drenagem urbana. / The process of occupation and growth of urban centers is usually based on an empirical urban planning, considering the interests of small social groups, and disjointed from other factors that compose a city, such as the hydrographic basin in which the municipality is inserted, the relief, the region's rainfall regime, which interfere with the rainwater drainage system and may present risks to people residing in unduly occupied areas. The disorderly increase of impermeable areas in urban centers causes impacts to the environment and damage to the population, such as floods, if is not done through a planning process. The greater number of impermeable spaces generates high surface runoffs and lead to drainage systems, often inadequate, at their limits of operation. In this sense, the present work sought to apply sustainable low-impact compensatory measures, green roofs, permeable pavements and rain gardens, in two small basins of the city of Campina Grande - PB, in order to mitigate the problems in the urban drainage system of the municipality. The hydrological simulation software used was the SWMM - Storm Water Management Model, with the objective of analyzing the reduction of surface runoff in basins with high and medium risk to floods. The urban drainage compensatory measures were applied in two scenarios: current use observed at the time of the research and with the maximum waterproofing provided in legislation. The results showed a satisfactory performance, with, in some cases, 100% of flor reduction, in the implementation of all the measures, however, the efficiency in the reduction of the volume generated varies according to the areas and criterias` application. The use of the proposed measures is not capable of minimizing all hydrological impacts of urban use and occupation, but the results of this study suggest that sustainable infrastructures should be discussed as a new method of urban flood control, along with the management and control of land use and occupation. It is expected that these results will contribute to future studies, so that the city of Campina Grande, as well as other cities with similar problems, reach an efficient and sustainable level of urban drainage services.
70

LIGHTING MASTER PLANFOR MARCHAMALOSALT FLATS

Garcia Rodriguez, Raquel January 2019 (has links)
The Marchamalo salt flats, built in the 18th century, are located near Cabo de Palos, Murcia (Spain), in a hot spot area with constant pressures of tourism and urban speculation. The salt flats are currently abandoned, but its landscape and ecological value still subsist. This Thesis aims to develop a low impact lighting Master plan for Marchamalo salt flats in which a comprehensive analysis is relevant for the design project. A holistic analysis method is employed which considers three agents: “Space”, “Humans” and “Light” to which the factor “Flora & Fauna” was added since the original method was developed for an urban context while the salt flats are located in a natural protected area. Each agent is studied in depth, separately and the interrelations between them. Applying the interpretation of facts and data developed in the analysis and by means of alternative urban lighting solutions like phosphorescence, portable lamps and smart controls; a customised urban lighting design is proposed based on the salt flats identity, preservation of darkness, multi-sensorial experience of the realm and the reconnection with the sky and nature. The lighting proposal will also be the guiding thread to raise awareness about the importance of protecting the heritage in the Region of Murcia in general, taking as a particular example the case of Marchamalo salt flat.

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