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1
Croft, Alex. "The effects of thin layer dredge material disposal on tidal marsh processes, Masonboro Island, NC /". Electronic version (PDF), 2003. http://dl.uncw.edu/etd/2003/crofta/alexcroft.html.
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Phelan, Richard B. "OTF DGPS for estuarine dredging and sounding surveys". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ30017.pdf.
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Mo, Kon-shing. "Comparing EA (EIA) process of dredging projects between United States (US) and Hong Kong (HK) /". Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B14723402.
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Siyam, Ahmed Musa. "Reservoir sedimentation control". Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324265.
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Vecino, Gustavo Angel. "Applying web-based project management techniques to dredging projects". College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7796.
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Thesis (M.S.) -- University of Maryland, College Park, 2007.Thesis research directed by: Dept. of Civil and Environmental Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Boyd, Sian Ellen. "A comparative study of the responses of microfaunal and nematode assemblages to the disposal of dredged material". Thesis, Bangor University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298890.
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Poon, Sau-man Anne y 潘秀文. "Dredging and reclamation impact on marine environment in Deep Bay". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31253866.
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Cooper, Keith. "Marine aggregate dredging : a new regional approach to environmental monitoring". Thesis, University of East Anglia, 2013. https://ueaeprints.uea.ac.uk/48093/.
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The subject of this thesis is the marine aggregate dredging industry, and specifically the approach taken to the monitoring of environmental effects on the seabed. The thesis forms the evidence required to allow the author to be examined for a PhD by Publication, and comprises of a list of the author’s publications, a confirmation of the author’s contribution to the multi-authored papers, and a critical analysis of the published work. The critical analysis takes the form of an essay, in which a case for switching to a new system of environmental monitoring is outlined. The essay presents a logical development of ideas, starting with a description of the aggregates dredging industry. This is followed by a critical analysis of the author’s past research, with a particular emphasis on how the findings from this work are relevant to the issue of monitoring. This earlier work has addressed themes of: Impact (Cumulative Effects), The Relationship between Sediments and Benthos, Recovery, Restoration, Habitat Mapping and Natural Variability. The essay then describes the current approach to monitoring, together with its limitations. This is followed by a description of the new monitoring approach, with an explanation of why it is considered more suitable for meeting the needs of both the industry and the industry regulators. The essay considers what steps would need to be taken to implement the approach in the major dredging regions of the UK.
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Poon, Sau-man Anne. "Dredging and reclamation impact on marine environment in Deep Bay /". Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18734558.
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Jory, Adam Matthew. "The fishery and ecology of the scallop Pecten maximus (L.) in Guernsey". Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313326.
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Welsh, John M. "Characterization of the evolution of a relocated tidal inlet: Mason inlet, North Carolina /". Electronic version (PDF), 2004. http://dl.uncw.edu/etd/2004/welshj/johnwelsh.pdf.
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Velasco, Victor V. "Evaluation and cost comparison of anti-siltation systems and traditional dredging methods". Springfield, Va. : Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA387800.
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Fehrenbacher, Fairlight Marie. "Predicting shoreline change due to nearshore dredging at Folly Island, South Carolina". Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/21527.
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Barkley, Aaron. "Cost and Efficiency in Dynamic Government Outsourcing: Evidence from the Dredging Industry". Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/970.
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This dissertation contains essays on government outsourcing and identification of dynamic binary choice models. The first essay, titled “Mixed-Delivery of a Public Good: An Empirical Case Study of the Dredging Industry,” provides a descriptive analysis of the United States dredging industry. The industry has several features that make it an interesting area to study delivery of public goods; most notably, provision of dredging services in the US are split between in-house provision by the US Army Corps of Engineers and contracting out to private sector dredging companies. Patterns of in-house government project selection suggest that government prefers to complete smaller projects and also indicates the presence of complementarities across projects arising from travel distance between project sites. In the second essay, “Semi-parametric Identification of Dynamic Binary Choice Models,” I give conditions under which both the per-period payoffs for each state and the distribution of the random, unobserved component of agent utility are identified. Most previous work in dynamic discrete choice models has used the assumption that the distribution of choice-specific utility shocks are known. I show that two conditions suffice to identify this distribution: first, that there is a period in which there is no future value component for agents. This can arise due to either non-stationary state transitions or a finite time horizon. Second, I assume that there is a state variable that enters into the utility for one of the choices through a known function. This allows for identification of the distribution of the unobserved utility component through variation in this state variable in the static periods. Finally the last essay, titled “Cost and Efficiency in Government Outsourcing,” builds a dynamic binary-choice model of government outsourcing decisions and applies the model to the dredging industry described in the first essay. I investigate the effect of government outsourcing on total expenditures and efficiency by considering how outsourcing decisions are determined along two dimensions: (i) cost differences between private firms and government suppliers of public goods and (ii) dynamics arising from cost complementarities and capacity constraints. Identification of the model uses the identification results from the second chapter, and allows for identification of the full distribution of government project costs. Model estimates indicate substantial cost savings due to outsourcing but also that government presence in the market is important for cost reduction. A counterfactual policy experiment featuring direct competition between government and private sector firms finds a total expenditure reduction of 17.1%.
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Edwards, Sion Charles. "The behaviour of mercury and copper contamination in a lowland river system and their accumulation by some biota". Thesis, Imperial College London, 1995. http://hdl.handle.net/10044/1/7457.
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Pennington, David. "Studies of aspects of predation on the Manx scallop, Pecten maximus (L.) populations". Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366391.
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Ma, Kit-cheong James. "Hong Kong Government criteria for assessing contamination levels of dredged marine sediments /". Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22264474.
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n, Hussin Wan Mohd Rauhan. "Measurement of changes in marine benthic ecosystem function following physical disturbance by dredging". Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/2838.
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Measuring the impact of physical disturbance on macrofaunal communities and sediment composition is important given the increased demand for the exploitation and disturbance of marine ecosystems. The aim of the present investigation was to provide a comprehensive study about the extent to which the disturbance (especially aggregate dredging) may affect benthic ecosystem function. The first part of the thesis concerns a field investigation of the impacts of dredging on the benthic community and related ecosystem function which was measured by different approaches including traditional methods based on benthic community structure and a more novel approach based on the functional traits of benthic organisms. The assessment was done by comparing dredged sites (Area 222, southeast England) with nearby undisturbed reference sites from the years 2001 to 2004 and in 2007. In general, low dredging intensity did not appear to impose great impacts on the benthic community and related ecosystem function compared to the higher intensity activity. Most of the analyses suggested that the community at the high dredging intensity site had yet to recover at the end of this study period. Among many factors related to the recovery of the benthic community was sediment composition where gravel deposits appeared to support a faster biological recovery. Meanwhile, the recovery of species with specific traits, such as tube-building and filter feeding also indicate a faster recovery for the whole community. The experimental work to determine different impacts of Hediste diversicolor on its surrounding depending on its relative size is discussed in Appendix 1.
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Nicholls, C. "The environmental management of the marine aggregates dredging industry in England and Wales". Thesis, Cardiff University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410352.
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Manap, Norpadzlihatun. "Risk-based decision making framework for the integrated environmental management of dredging sediments". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/18052.
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Many environmental management tools have been developed aiming to reduce the impacts of dredging and protect the environment. As this has typically not been done in an integrated way that takes into account the socio-economic, environmental, technical and managerial aspects of dredging, there is a need to develop an integrated decision making tool to manage the impacts of dredging and help decision makers make sustainable decisions concerning dredging. The aim of this study was to develop a risk-based decision making framework for the integrated environmental management of dredging sediments in order to reduce the impacts of dredging and to lower the cost of environmental quality analysis and management. Selection of the best sediment management option using the risk-based approach of integrated environmental management has the potential to help effectively balance and prioritize the various socio-economic, environmental, technical and managerial aspects of dredging. The proposed framework will therefore utilize this concept throughout its six developmental steps. The first step reviews the literature on the impact of dredging and the two main factors that determine its magnitude, namely sediments and dredging technology. In order to manage the impacts of dredging efficiently, the relationship between scientific evidence and dredging activities will be assessed in the second developmental step. This step evaluates historical evidence from three dredging projects undertaken between 2006 and 2008 on the rivers of Sungai Sitiawan and Sungai Dinding, Perak, Malaysia. Monitoring and fish toxicological data from these projects are analyzed to determine their relationship with dredging activities performed in these rivers, with Geographic Information System (GIS) software used to illustrate the relationships found. The third developmental step assesses dredging problems other than the environmental impacts using Driving force-Pressure-State-Impact-Response (DPSIR) analysis, an IEM-based tool. This tool was employed in Malaysia’s dredging industry using interviews and a questionnaire-based survey. Dredging experts, including representatives from port operators, manufacturing companies and dredging contractors, were interviewed in 2008, with the socio-economy and management being found as the main drivers, together with environmental impacts, affecting dredging stakeholders in Malaysia. In 2010, further dredging experts (including marine ecologists, registered chemists, professional and chartered engineers, environmental consultants, university professors and environmental analysts) responded to the questionnaire, with results suggesting that governance of dredging in Malaysia is weak and that it is essential for Malaysia to review its current dredging environmental management tools and practices. The fourth developmental step develops the first stage (screening) of the proposed framework based on understanding provided by the three steps developed previously and demonstrated using Malaysia as a case study. This screening stage utilizes the historical dredging monitoring data and the contamination level in media data into Ecological Risk Assessment (ERA) phases, which have been adjusted for benefits in cost, time and simplicity. Using case studies from Malaysia, the fifth developmental step (Tier 1) shows how Multi-Criteria Decision Analysis (MCDA) can be used to analyze and prioritize dredging areas based on environmental, socio-economic and managerial criteria and is demonstrated for the Tier 1 stage. The results from MCDA will be integrated into Ecological Risk Assessment (ERA) to characterize the degree of contamination found in the areas. Priority areas, their degree of contamination and other concerns are then identified and brought forward to the sixth developmental step (Tier 2 stage). The Tier 2 stage is demonstrated using previous findings and analyzed using MCDA, in order to identify the best sediment management option, accounting for the economic, environmental and technical aspects of dredging.
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Cooper, Peter. "Remote monitoring and control of marine engines and process instrumentation for dredging operations". Thesis, Cooper, Peter (2015) Remote monitoring and control of marine engines and process instrumentation for dredging operations. Honours thesis, Murdoch University, 2015. https://researchrepository.murdoch.edu.au/id/eprint/29839/.
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A project was carried out in conjunction with an Australian dredging company and served the purpose of increasing their operational efficiency through advanced monitoring and control. A system consisting of wireless communications, PLCs, HMIs and SCADA was implemented to provide the dredge operator and management staff remote monitoring and control of the operation.
The pre-existing dredging arrangement relied on frequent visits to the land-based engine-driven booster pump to tune the engine speed for optimal pipeline flow. These visits were carried out by land-based staff, at the request of the offshore dredge operator who monitors the flow via a magnetic flowmeter. The dredge operator needed to control the booster pump remotely to save time and resources. For improved project supervision, it was also envisaged that management should have access to daily shift reports and live monitoring from the office.
Electrical systems were implemented at the dredge and booster pump to accommodate wireless and wired industrial networks. The new arrangement allows the dredge operator to monitor and control operations via a HMI display mounted in the dredge cabin. From the cabin, the dredge operator can view data from both engines and process instrumentation such as pipeline flow. The booster pump also contains a HMI display from which it can be independently monitored and controlled. A SCADA system was installed on the dredge to generate daily reports and provide management with live access to operations from the office.
The new system was a complete success increasing production efficiency and improving operations management. Eliminating visits to the booster pump and improved supervision of equipment significantly reduces dredging downtime. Access to daily reporting and live operations allows management to supervise operations without travelling to site resulting in cost and time savings. This project not only provides a solution to a gap in the dredging market, it provides a knowledge-base for future students or engineers to continue development of diesel engine monitoring and control using commercially available components.
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Milburn, Elizabeth Anne. "The effects of dredging on dissolved oxygen in agricultural waterways in King County, Washington". Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Spring2007/E_Milburn_030907.pdf.
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Jakku, Emma y n/a. "Murky Waters? Science, Politics and Environmental Decision-Making in the Brisbane River Dredging Dispute". Griffith University. Australian School of Environmental Studies, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040810.131650.
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Environmental sociology and the sociology of scientific knowledge provide a strong theoretical foundation for investigating the role of science in environmental disputes. The field of environmental dispute resolution has built a body of literature, outlining the techniques and practices that underpin the successful resolution of disputes, over controversial environmental issues. However, the literature on dispute resolution has generally neglected the role of science in environmental disputes. This thesis develops a theoretical framework based on concepts from environmental sociology and the sociology of scientific knowledge in order to critically examine the role of science in environmental disputes. In particular, this thesis combines the theory on claims-making from environmental sociology with actor-network theory and the theory on boundary-work from the sociology of scientific knowledge, to analyse the way in which science was involved in the dispute over phasing out extractive dredging from the Brisbane River. Data were collected from qualitative in-depth interviews with key players in the Brisbane River dredging dispute and combined with analysis of relevant documents and newspaper articles. Each of the components of the theoretical framework developed in this thesis contributes to an in-depth analysis of the way in which science was involved in the dredging dispute. The environmental claims-making analysis examines the way in which the claim that extractive dredging was an environmental problem for the Brisbane River was constructed and contested. The actor-network analysis compares the two competing actor-networks that were developed by one of the major concrete companies and by the anti-dredging campaigners. The boundary-work analysis examines the social construction of the science / politics border as an important site of boundary-work, before exploring other related forms of boundary-work within the case study. When combined, these theories highlight the social and political processes that underpin the inherent difficulties associated with applying science to effective environmental dispute resolution. The theoretical framework developed in this thesis highlights the way in which an analysis of environmental claims-making, actor-networks and boundary-work, extends the literature on environmental dispute resolution. This thesis therefore makes a significant contribution to the field of environmental dispute resolution, by illustrating the advantages of drawing on theoretical perspectives from environmental sociology and the sociology of scientific knowledge.
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Lau, Shing-cheong y 劉勝昌. "A review of the management of the dredging silt/sand from Hong Kong waters". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31255553.
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Mo, Kon-shing y 巫幹成. "Comparing EA (EIA) process of dredging projects between UnitedStates (US) and Hong Kong (HK)". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31253209.
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Fischer, Jason L. "Fish community response to habitat alteration: impacts of sand dredging in the Kansas River". Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/13601.
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Master of ScienceDepartment of Biology
Craig Paukert
In-stream dredging is a common practice in rivers worldwide that can affect fish and fish habitat. We investigated the magnitude of these alterations and their influence on the fish community of the Kansas River, a large sand bed river. Fishes were collected monthly from June 2010 to June 2011 in Edwardsville and Lawrence, KS from 12, 1-km reaches (three actively dredged, two historically dredged that have not been dredged in at least one month, and seven control reaches) with bottom trawls, seines, and electrofishing. Water depths and velocities were measured with an acoustic doppler current profiler and interpolated in ArcGIS at all 12 reaches. Actively dredged reaches had proportionally more deep water habitat (> 3 m) and lower velocity (< 0.15 m/s) near the river bed than control reaches (P < 0.01 and P = 0.04, respectively). However, the mean proportion of shallow water habitat (< 0.5 m), high velocities near the river bed (> 0.30 m/s), low velocity habitat (< 0.25 m/s), and high velocity habitat (> 0.75 m/s) were similar among all reach types (Ps > 0.05). A canonical correspondence analysis was used to characterize relationships among habitat variables, reach types (actively dredged, historically dredged, and control), and catch per unit effort (CPUE) of fishes in the Kansas River. Mean velocity and depth explained a significant amount of variation in species CPUE; however, reach type was not a significant factor for any of the gear types for any season. Our results show that dredging in Great Plains Rivers can increase depths, but alterations to fish community structure was not evident, likely because many of these fishes are adapted to a range of habitat conditions and are highly mobile.
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Jakku, Emma. "Murky Waters? Science, Politics and Environmental Decision-Making in the Brisbane River Dredging Dispute". Thesis, Griffith University, 2004. http://hdl.handle.net/10072/366055.
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Environmental sociology and the sociology of scientific knowledge provide a strong theoretical foundation for investigating the role of science in environmental disputes. The field of environmental dispute resolution has built a body of literature, outlining the techniques and practices that underpin the successful resolution of disputes, over controversial environmental issues. However, the literature on dispute resolution has generally neglected the role of science in environmental disputes. This thesis develops a theoretical framework based on concepts from environmental sociology and the sociology of scientific knowledge in order to critically examine the role of science in environmental disputes. In particular, this thesis combines the theory on claims-making from environmental sociology with actor-network theory and the theory on boundary-work from the sociology of scientific knowledge, to analyse the way in which science was involved in the dispute over phasing out extractive dredging from the Brisbane River. Data were collected from qualitative in-depth interviews with key players in the Brisbane River dredging dispute and combined with analysis of relevant documents and newspaper articles. Each of the components of the theoretical framework developed in this thesis contributes to an in-depth analysis of the way in which science was involved in the dredging dispute. The environmental claims-making analysis examines the way in which the claim that extractive dredging was an environmental problem for the Brisbane River was constructed and contested. The actor-network analysis compares the two competing actor-networks that were developed by one of the major concrete companies and by the anti-dredging campaigners. The boundary-work analysis examines the social construction of the science / politics border as an important site of boundary-work, before exploring other related forms of boundary-work within the case study. When combined, these theories highlight the social and political processes that underpin the inherent difficulties associated with applying science to effective environmental dispute resolution. The theoretical framework developed in this thesis highlights the way in which an analysis of environmental claims-making, actor-networks and boundary-work, extends the literature on environmental dispute resolution. This thesis therefore makes a significant contribution to the field of environmental dispute resolution, by illustrating the advantages of drawing on theoretical perspectives from environmental sociology and the sociology of scientific knowledge.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
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Johnson, Charley R. "Migration of Dredged Material Mounds: Predictions Based on Field Measurements of Waves, Currents, and Suspended Sediments, Brunswick, GA". Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-04082005-145658/unrestricted/johnson%5Fcharley%5Fr%5F200505%5Fmast.pdf.
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Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2005.F. Michael Saunders, Ph.D., Committee Member ; Kevin Haas, Ph.D., Committee Member ; Paul A. Work, Ph.D., Committee Chair. Includes bibliographical references.
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Bayer, David Michael. "Choreographing Sediment". Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/54029.
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In 2016 the Panama Canal expansion is set to open, allowing a new class of ships to call on east coast ports. The dredging involved in deepening navigation channels to ensure safe passage of these vessels will place an increased amount of pressure on containment facilities up and down the coast. With limited disposal space, and increasing volumes, many ports have begun to rethink the treatment of this excess material. This thesis explores the prospect of dredge material being more than engineered fill. It suggests that dredge processing can become the basis for a new form of productive recreational landscape, one that can engage the public in a conversation of the spatial and material operations that sustain our lives. It works blur and dissolve the boundaries that have been erected between working landscapes and the public realm, and seeks to create a landscape that establishes a new sense of place prepared to mark the future of the new working urban waterfront; one where industrial operations generate new ecological substrates, and where productive frameworks become recreation networks.Master of Landscape Architecture
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Morris, Stephanie M. "Effects of Dredging-Induced Sedimentation and Turbidity on Two Species of Stony Corals of Southeast Florida". NSUWorks, 1993. http://nsuworks.nova.edu/occ_stuetd/351.
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Sedimentation parameters, turbidity, extension (linear) growth, bleaching and polyp expansion were examined prior to, during, and after the dredge and fill activities associated with the first renourishment of Hollywood and Hallandale beaches, 1991. During the project, approximately 1.1 million cubic yards of beach compatible material was taken from two offshore borrow areas and placed on 5.3 miles of beach. Treatment stations were at offshore (adjacent to the borrow area) and nearshore (adjacent to fill area) locations. Control stations were placed at least 3km north, offshore of John U. Lloyd Beach State Recreation Area. Two coral species abundant in this area, Solenastrea bournoni and Dichocoenia stokesii, were monitored monthly on each reef for signs of bleaching and polyp expansion, indicators of stress and surface clearing ability respectively. After dredging was completed, the corals were collected for growth analysis (linear extension) by the Alizarin stain method. At treatment stations, associated with dredging, a significant decrease in extension growth rate in S. bournoni but not D. stokesii occurred. A decrease in fossa length of D. stokesii suggested that dredging effects caused a change in columella shape. Bleaching occurred in many of the colonies but may have been caused by an unknown factor. Polyp expansion, a means of sediment rejection, did not correlate with the proximity to dredging. The corals may be relying on other means of sediment removal. This study suggests that the effects of dredging on stony corals are species specific.
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Jacobsen, Olov. "Autonomous Underwater Cable Suspended Dredging System : A method to combat the eutrophication of the Baltic Sea". Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175883.
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An autonomous underwater cable suspended dredging system is proposed with the application of combating the excess of nutrients in the Baltic Sea. The focus of the thesis is on modelling and designing of the control system used to guide an end-effector supplied with a pump along a predetermined path. The end-effector is guided with the help of four cables that are each controlled by a servomotor. The buoyancy of the end-effector in combination with the cables keeps the end-effector a few meter above the seafloor. The sediment is collected with tubes hanging down from the end-effector. Due to the large dimensions of the system a combination of force control and position control passed through a force distribution algorithm is suggested. A simulation of the system shows promising results with ability to trace the predetermined path closely.Ett förslag till ett autonomt vajerstyrt muddringssytem för undervattensbruk har tagits fram som ska används för att motverka övergödningen i östersjön. Uppsatsen fokuserar på modelleringen och designen av reglersystemet för att styra en plattform utrustad med en pump längs en förutbestämd sträcka. Plattformen styrs med hjälp av fyra vajrar som i sin tur styrs av varsin servomotor. Flytkraften hos plattformen i kombination med vajrarna håller plattformen några meter från havsbotten. Bottensediment pumpas upp genom slangar som hänger ner från plattformen. På grund av systemet storlek regleras styrningen av plattformen genom båda kraft och position samt använder en algoritm för att distribuera krafterna mellan vajrarna. En simulering av systemet har utförts och visar på god förmåga att reglera positionen av plattformen i relation till den förutbestämda sträckan.
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Tamuno, P. B. L. "Eco-livelihood assessment of inland river dredging : the Kolo and Otuoke creeks, Nigeria, a case study". Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/2334.
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Conventionally environmental assessments (EAs) have been carried out to enhance the understanding of the environment and for the purpose of developing appropriate environmental management and protection strategies. There are, however, limitations to the application of traditional EA approaches, particularly in rural communities in the developing world, where livelihood is dependent on common pool resources (CPRs), and baseline data are inadequate or unavailable. Eco-livelihood assessment (EcLA) is an adaptive approach that integrates a people focused sustainable livelihood approach with ecological assessment, as well as exploring traditional eco-livelihood knowledge (TELK). EcLA is identified as a promising EA tool that could help environmental professionals in planning for equitable development. This approach has been used in the Kolo and Otuoke Creeks, Niger Delta, Nigeria to investigate the ecological impact of dredging that may impact on livelihoods in such a rural setting. Ecological and social surveys have been carried out in four communities in the Study Area; two Test communities and two Reference communities (two communities from each study creek). The information collected from the social survey includes TELK, and has been used to build up a baseline scenario of the Study Area. Abundance and diversity of fish are good indicators of the eco-livelihood impacts of inland river dredging. The research shows that livelihood characteristics, river use profile, fish species diversity and abundance are very similar among all four sample communities. In addition, all sample communities have been associated with similar natural and human induced environmental consequences except that the Test communities have had river sections dredged for the purpose of land reclamation representing the baseline scenario. The analysis of the results of the ecological survey shows a difference in fish catch per unit effort, catch per unit hour, and species diversity between the Test and Reference communities, this have been attributed to the impacts of inland river dredging. The study shows that TELK has a place in environmental assessment, and that eco-livelihood assessment is one promising environmental assessment approach that could be used in areas where livelihood is strongly dependent on common pool resources.
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MacDonald, David Simpson. "Ecological studies on the effects of scallop dredging on the benthos of the North Irish Sea". Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333574.
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Buchanan, David. "The application of information technology to dredging management (with particular reference to the Port of Clyde)". Thesis, University of Strathclyde, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264569.
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Barber, Michael R. "Effects of Hydraulic Dredging and Vessel Operation on Atlantic Sturgeon Behavior in a Large Coastal River". VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4792.
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The tidal James River, a focus of VCU's Atlantic Sturgeon program, supports both commercial shipping and hydraulic dredging. These anthropogenic threats present documented but preventable sources of mortality to the endangered species. Using three separate VEMCO Positioning System (VPS) receiver arrays, spatial data of previously-tagged fish were collected. ArcGIS and Programita software were used to analyze fish spatial distributions in the presence and absence of potential threats, using additional data including automatic identification system (AIS) vessel locations, vessel passages compiled using camera footage, and dredge records provided by the US Army Corps of Engineers. The data showed a change in distribution associated with vessels that varied according to river width but not vessel type. Dredging was associated with differences in spatial distribution, but more clearly for adults than sub-adults. The responses of Atlantic Sturgeon provide information necessary to propose potential threat mitigations, including seasonal restrictions for both vessels and dredging.
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Gorham, Richard Arthur. "All dredged up and no place to go : the disposal of contaminated dredged material from greater Vancouver, British Columbia, into the neighbouring strait of Georgia". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24673.
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The thesis provides an integrated review and analysis of strategic scientific information from which management procedures for the environmentally acceptable disposal of dredged materials from Greater Vancouver into the Strait of Georgia are determined. An analysis of reported and suspected contamination of Vancouver's waterways identifies trace metals and hydrophobic organic chemicals that warrant concern by authorities responsible for the management of dredged material disposal. The processes, transformations and pathways of these contaminants in the marine environment subsequent to dredged material disposal are reviewed. It is argued that a really confined degradation of suitable disposal sites is of negligible concern, but that release of contaminants from the disposal area, were it to occur, could have unpredictable and perhaps substantial environmental consequences. The major potential pathway of contaminant release from dredged material during or subsequent to disposal is via the resuspension and transport of fine particulate material. Biological accumulation of contaminants and their transport through the food chain is a potentially significant release pathway for hydrophobic organic contaminants. Biological transformation to more soluble metabolites is also potentially significant for mercury and some of the less chlorinated and lower molecular weight organic compounds of concern. Desorptive release of contaminants from the disposed sediments into solution is usually negligible, with the possible exceptions of cadmium and mercury. A review of the physical factors that promote contaminated sediment erosion and dispersion during or subsequent to dredged material disposal identifies oceanographic characteristics where such release will be minimal. There are only four areas within the Strait of Georgia that exhibit these characteristics. Two of these areas are adjacent to valuable and sensitive biological resources and are consequently unsuitable as ocean dumping sites. Dredged material disposal at the other two sites, one near Smelt Bay, Cortes Island, and the other off McNaughton Point, Sechelt Peninsula, should result in minimal adverse environmental impact. Available methodologies to identify dredged materials with contaminant levels that preclude their environmentally acceptable disposal at these recommended sites are discussed.Science, Faculty of
Resources, Environment and Sustainability (IRES), Institute for
Graduate
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Amende, Roger Aln. "An evaluation of the standard elutriate test as an estimator of contaminant release at the point of dredging". Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/101340.
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While release of contaminants during dredged material disposal operations has long been the subject of environmental concern, the potential release of pollutants during the dredging process has recently come under the scrunity of federal and state regulatory agencies. The mechanical action of a dredging operations causes resuspension of sediment particles and release of soluble contaminants to the water column. A predredging test is essential to estimate the amount of soluble release at or near the point of dredging to ascertain potential water quality impact. The Standard Elutriate Test has proven to be a good estimator of soluble contaminant release for dredged material disposal operations and researchers have recognized that the processes involved at the point of dredging are similar to those involved with the open-water disposal of dredged material.
This research is an evaluation of the Standard Elutriate Test as an estimator of soluble contaminant release at the point of dredging. Data and field studies were conducted by the U.S. Army Corps of Engineers Waterways Experiment Station at five sites around the United States. A direct comparison was made between elutriate test data from predredging bottom sediment and water sample analysis taken at or near the point of dredging.
The Standard Elutriate Test satisfactorily predicted the release of soluble contaminants at or near the point of dredging in four out of the five sites in this study. The fifth site had extenuating circumstances that may account for the failure at this site. In this investigation, the elutriate test appears to overestimate the release of organics, nutrients and some heavy metals (Hg, Mn, Fe, and Cr).
Statistical analysis provided a predictive equation that can be used to estimate the upper-bound value a constituent concentration will approach based on elutiate test data and a specified confidence level.M.S.
38
Hoe, Tian Hee. "The prediction via a mathematical model of the "primary" self-weight consolidation curve of silt particles during zone settling". Master's thesis, Mississippi State : Mississippi State University, 2001. http://library.msstate.edu/etd/show.asp?etd=etd-11152001-103032.
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Avila, Christian L. "Effects Associated with Dredging for Beach Renourishments on Reef Fish Communities Offshore of Miami-Dade County, Florida:". NSUWorks, 2006. http://nsuworks.nova.edu/occ_stuetd/251.
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Beach erosion is an ongoing problem in South Florida. Beach replenishment has been the primary means of maintaining these economically important beaches, and dredging offshore sand deposits, adjacent to reef tracts, has been the pervasive method since the 1970's. Over the past ten years, greater attention has been paid to potential impacts dredging can have on adjacent reef communities, which has led to increased monitoring efforts. With the increase in monitoring efforts, scope has expanded from a strict focus on the benthic community to include the fish communities. This study evaluates the effects of dredging on reef fish communities associated with two separate beach replenishment projects, offshore of Miami-Dade County, Florida, U.S.A. Monitoring programs were developed and conducted by the Miami-Dade, Department of Environmental Resources Management (DERM). Monitoring took place between March 1997 and September 2000, with one project in northern portion of the county, off offshore of Golden Beach, and the other in the southern portion offshore of Key Biscayne. Both monitoring programs employed a Before After Control Impact design, with established test and control reef stations. Eight reef fish visual point count censuses (Bohnsack and Bannerot, 1986) were performed at each station prior to dredging, immediately following dredging, and three periods at bi-quarterly intervals after that.
In general evaluations of both project,s showed no indications that dredging activities had major impacts on the fish communities of adjacent reefs. For the Golden Beach project, there was one aspect of the analysis, which may be indicative of dredging related impacts; was species richness at one test station declined significantly following dredging activities (ANOVA p=0.047). However, in terms of abundance, diversity and Multidimensional scaling (MDS) plots of the Bray-Curtis dissimilarity index did not indicate that dredging activities impacted the test station. During the monitoring period of the Key Biscayne project, the south Florida region was impacted by two tropical storm events, which obscures the isolation of impacts associated with dredging. Changes in the reef fish communities, consistent with the impact and recovery of the tropical storms are evident in species richness, abundance, and MDS plots of the Bray-Curtis dissimilarity index, at both the test and control stations.
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Selden, Justin D. "The Effect of Dredging on Fish Communities in Agricultural Streams in Crawford, Sandusky and Seneca Counties of Ohio". University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1372421206.
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Lima, Lilian Rouse da Silva. "Dragagem, transporte e disposição final de sedimento de leito de rio - estudo de caso: Calha do Rio Tietê - Fase II". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3147/tde-30092008-155243/.
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As obras de Ampliação da Calha do Rio Tietê fazem parte de medidas estruturais que visaram ao aumento da capacidade de vazão para o controle das enchentes na RMSP. A regularidade da capacidade de vazão dependerá, dentre outras ações, de dragagens de manutenção e retirada do material dragado, cuja destinação é bastante problemática. O objetivo deste trabalho é a elaboração de um estudo sobre o processo de dragagem, transporte e disposição final de material de leito de rio por meio da apresentação do processo adotado no estudo de caso: Ampliação da Calha do Rio Tietê Fase II. Para esse fim, são abordados os principais aspectos técnicos, ambientais, sociais e econômicos relativos às obras do estudo de caso, dando ênfase à gestão do sedimento dragado, que busca estar em consonância com as normas e diretrizes legais vigentes. São finalmente enunciadas as principais recomendações e conclusões que devem ser aplicadas na gestão do sedimento dragado do Rio Tietê.The works of Enlargement of Rio Tietê\'s Gutter (Waterway) are part of structural measures that objective increase the flow capacity for inundation control in RMSP (Metropolitan Region of São Paulo). The regularity of the flow capacity will depend, among other actions, of maintenance dredgings and retreating of dredged material, whose destination is plenty of problem. The aim of this work is the elaboration of a study about the dredging process, transport and final disposition of the river bed sediment through the presentation of the process adopted in the case study: Enlargement of Rio Tietê\'s Gutter Phase II. For that purpose, the main technical, environmental, social and economical aspects related to the works of the case study are discussed, giving emphasis in the administration of the dredged sediment, that seek fitting to the in course norms and legal guidelines. Finally, the main recommendations and conclusions that should be applied in the administration of Rio Tietê\'s dredged sediment are examined.
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Panasik, Gina M. "Effects of the addition of dredged sediment to a marsh ecosystem on benthic microalgal biomass /". Electronic version (PDF), 2003. http://dl.uncw.edu/etd/2003/panasikg/ginapanasik.html.
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Sarkar, MK. "Performance of an auger dredging cutter for subsea dredging and mining". Thesis, 2013. https://eprints.utas.edu.au/17131/7/Sarkar_whole_thesis_ex_pub_mat.pdf.
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Increasing use of deep-water dredger and miner vehicles has been anticipated for resource collection, engineering construction and environmental protection. Among existing deep-dredging equipment designs submersible dredgers have advantages over others such as surface designs.
Considering the limitations of commercially available and conceptualised submersible dredgers, a different type - the ‘Swimming Remotely Operated Submersible Dredger’ (SROSD) is conceptualised in this research. In its working mode, it imitates a walking motion by using spuds that are also used for station keeping during dredging. When required, the vehicle can swim by means of vector thrusters. The vector thrusters also help in position-keeping and motion-control during swimming. To offset high forces generated during excavation of hard materials, spuds, variable buoyancy tanks and control planes are included as secondary station-keeping devices. The general arrangement and the sub-systems of the conceptualised vehicle are described.
For swimming and control in a submerged condition, the vehicle is ballasted to a neutrally buoyant condition. Balancing of the excavation forces is necessary for efficient production and this is a design problem with submersible dredgers. A transverse axis auger cutter capable of surgical cutting with low force fluctuations is used in the design. A theoretical model of the cutting forces in vertical and horizontal directions generated by this type of cutter is proposed.
An experiment was designed to measure the cutting forces generated by this cutter. Comparisons between the power requirements derived from the experiment and the theoretical model were done to validate the model. The measured experimental power requirements were found to be within the calculated power ranges for dredging loose to slightly compacted sand in similar operating conditions.
In a further experiment to assess the spillage from the cutter in operation, near and far field turbidity generation by the auger was measured by using turbidity sensors. Measurements of turbidity were taken to indicate the environmental impact of the auger. It was observed that the turbidity increase was dependent on the relative position between the probes and the auger and its shroud.
It is hoped that, through this work, a new design of vehicle, along with the reaction force analysis of the excavation and the turbidity measurements will significantly contribute to the evolution of existing deep-dredging and mining equipment leading to improved efficiency, increased mobility and position control while minimising environmental disturbance.
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Wei, Hsu Tang y 許唐瑋. "Dredging up the drift". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/04118869541411343483.
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You, Lin-Wan y 游令婉. "Planning of Dredging on River Stability". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/7r7ca7.
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碩士國立交通大學
土木工程系所
106
In this study, an investigation of dredging effects on longitudinal riverbed profile is made by simulating 64 dredging arrangements with varying bed slope and channel-to-floodplain width ratio. Using MAD (Mean Absolute Difference) of riverbed changes as the stability criterion, this study presents a preliminary investigation using Statistical Design of Experiment (DOE), in conjunction with a numerical sediment transport model (SRH-1D), to systemically evaluate various dredging arrangements for identifying the most desirable one. Through the “Analysis of Variance” of the results from the DOE under different dredging arrangements, relative importance of various dredging factors affecting riverbed stability can be analyzed. The study river reach extends from the Tianlun Dam to the Tachia River mouth to the Taiwan Strait within the Tachia River Basin. The selected four dredging sites along the study river reach are between Shonghu Bridge and Lilun Bridge. It is interesting to find that the dredging operation with minimal change in existing riverbed profile is not necessarily the best option to maintain channel stability. We also observe that a desirable dredging arrangement with low MAD value generally produces smaller fluctuation amplitude in the difference in time-averaged unit stream power along the channel ( TAUP ). To maintain channel stability, effective dredging operation is required to consider its influence on river regime. Therefore, the MAD value and the TAUP value can be used in the similar fashion, and the arrangement in which the MAD value and the TAUP value are arranged close to the minimum is the most desirable dredging arrangement.
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Shian-De, Luo y 羅先得. "Study of Reservoir Integrated Dredging Strategy". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/40788892631446389842.
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碩士國立成功大學
水利及海洋工程學系
87
The paper is put emphasized on the study of reservoir integrated dredging. At first, we evaluate the depth and velocity of every section in reservoir. Then the suspended load concentration convective-diffusion equation and the bed load continue equation are used to calculate the bed changes of reservoir as well as to calculate dredging efficiency. At last evaluate the integrated dredging strategy by the linear programming. Taking the A-GONG-DIAN reservoir for example, it has been the study of reservoir integrated dredging strategy. From the dredging strategy, as a result, we know that the water that has been consumed by hydraulic flushing is higher than mechanical excavation and dredger dredging. Because the mechanical excavation excavates the sediment deposits that have exposed from the reservoir, it does not consume water. Dredging efficiency of dredger is related with the situation of the sediment deposits in the reservoir, often form 5 to 10%, and flushing and empty is 0.393%, as to drawdown flushing is about 4 to 8% for it is related to the flood and the water level of reservoir. From the result of the linear programming, we know that if we take the water consumption as the objective function, the dredger and the mechanical excavation would be the best choice.
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Tsai, Wen-Fu y 蔡文富. "The study of the harbor dredging survey". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/87322920762902508532.
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碩士國立臺灣海洋大學
河海工程學系
93
The purpose of this study is to investigate the hydrographic survey drawings and dredge volume computation with the data from pre dredge surveys and often dredge surveys on a harbor dredging plan. The principles and methods of harbor dredging surveys standards are explored in this paper. The Keelung Harbor dredging plan is taken as an example. The softwaves “Surfer” and “LeadSurvey” with the methodology of trapezoidal rule and average and area volume respectively are used for dredge volume computation. The comparisons of the difference between them are also made for further reference on practical work of harbor dredging surveys.
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Lou, Hsien-Huan y 婁賢宦. "Shihmen Reservoir dredging project Countermeasures of improving". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/32162769548453710523.
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碩士國立臺灣海洋大學
河海工程學系
103
Shihmen Reservoir serves multiple functions, such as irrigation, power generation, public water supply, flood control and tourist attraction, making it an important water resource facility. It also plays an important role in economic development and industrial upgrading. Due to the steep slopes, fast-flowing streams, and large and concentrated annual rainfall in Taiwan as well as the result of the rapid mountain area development at the reservoir upstream, the reservoir storage capacity and function have declined gradually, and the domestic water use is in a situation beyond control. To strengthen the water storage and water supply functions of the reservoir, the dredging planning and management for the reservoir regeneration must be concerned. The current reservoir sediment management methods fail to take the sustainable use demand of the reservoir into account, and only control the sediment scouring to mitigate the incoming sediment quantity by the sediment volume estimation and the catchment area. Thus, many scouring control plans are not thoughtfully planned and implemented as expected, thus unable to achieve the expected result of reducing the sediment yield in the catchment area. The service life of Shihmen Reservoir has been reduced from the originally designed 90 years to 54 years, that is to say, the reservoir would come to an early end of its life in 2018. The service life of the reservoir may be extended by about 4 years by short-term mechanical dredging project (6 years for a phase) with the benefit-cost ratio of about 2.48. In addition, the catchment area governance and mechanical dredging, hydraulic sediment drainage and direct discharge of the raw water of a higher concentration into the downstream river channel by utilizing the typhoon and heavy rain period are all methods that could be used to reduce the reservoir sedimentation and maintain the equilibrium between scouring and deposition of the downstream river channel. The mechanism of reservoir sediment management is to transform the reservoir sedimentation issue into the concept of sustainable use. The key is to transform the concept of the reservoir life restricted by sedimentation into the water transfer, sediment transfer and being able to maintain the reservoir operation function. The basic sediment control strategies needing to be adopted for the sustainable use of the reservoir are described respectively as follows: 1.Downstream section of reservoir (by the dam): the dredging operation in this section is conducted by hydraulic sediment pumping. In the current construction situation of the sediment dredging part, the annual removal volume could reach about 300,000 cubic meters. Part of the incoming sediment can be made to pass over the reservoir area through the steel sediment drainage pipes and the sediment drainage tunnels, such as the high-concentration drawdown sediment drainage in the flood period, off-channel reservoir, sediment drainage by bypassing the reservoir, density current sedimentation prevention operation and other technologies. 2.Midstream section of reservoir (by Amuping): the dredging operation in this section is conducted by way of the hydraulic sediment pumping in principle. The annual dredging volume is expected to be 150,000 cubic meters; and the mechanical dredging and transfer is conducted in the drought period of the reservoir with the daily dredging volume amounting to about 1000 cubic meters. 3.Upstream section of reservoir (by Fuxing Bridge): in reducing the incoming sediment, the technologies like the slope scouring control in the catchment area and the upstream-channel sediment captivity are adopted to reduce the entry of sediment into the reservoir; and the large-size sediment storage dams (three dams in Yixing, Baling and Ronghua) are constructed. When the sediment storage capacity able to be provided by the tributaries at the reservoir upstream exceeds the upstream sediment supply volume, the reservoir benefit could be regarded as sustainable. Therefore, the sediment storage space needed may include the reservoir’s capacity reserved for sedimentation or one or several upstream sediment storage spaces. The annual removal volume of the dredging operation in this section is expected to be 150,000 cubic meters. There are many reservoir sedimentation reduction methods, as mentioned above; however, they fail to consider how to reduce the sedimentation at the reservoir outlet. In light of this, the sedimentation problem is suggested to e handled by steel sediment drainage pipe and sediment drainage tunnel in the middle and lower reaches of Shihmen Reservoir, thus reducing the sedimentation at the reservoir outlet and increasing the reservoir’s effective water storage capacity.
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Chen, Der-Sen y 陳德聲. "The Study of Military Harbor’s Dredging Cycle". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/44663921053601752579.
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碩士國防大學理工學院
軍事工程碩士班
97
Military harbor is an important strategic base of operation. The deposited silt will not only influence its routine assignments but also decrease its strategic advantages. There are several military harbors in the Navy, yet we could not dredge them effectively in the past due to less experience and capability. Therefore, it becomes an important issue for Navy to investigate the problems and to develop an evaluation model for effective dredging cycle. In this study, Fuzzy Delphi Method was firstly used to choose 15 important dredging factors from literatures, regulations, and results of the experts’ interviews and questionnaire. We separate these 15 factors into 4 criteria (Engineering economy, Risk management, Engineering technique, and Environmental impact) to establish a complete analytical structure, and then we use Fuzzy Analytic Hierarchy Process (FAHP) method to evaluate the weight of each criterion. At last, the best dredging cycle is calculated after summing the weights of all criteria by using Simple Weight Method. Besides the above results, another important findings show that the experts with different background have different suggestions about dredging factors. And these findings provide useful secondary information for future dredging plan. In the end of this research, a case study about the dredging cycle evaluation is investigated for a particular military harbor in southern Taiwan. We use the evaluated process proposed in this study to estimate the best dredging cycle successfully. It proves the developed model’s validity and applicability. Keywords: Dredging Project, Dredging Cycle, Fuzzy Multiple Criteria Decision Making
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Dismuke, Colin Patrick. "Experimental Investigation of the Flow Field in the Vicinity of the Suction Inlet of a Model Cutter Suction Dredge". Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11108.
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The purpose of this thesis is to describe the three-dimensional velocity flow field measurements in the vicinity of the inlet mouth of a cutterhead suction dredge. Using acoustic Doppler velocimeters (ADVs), an accurate visualization of the velocity flow field was used to determine the region of influence around the cutterhead. Similitude is used in the experimental study to determine the correlation between the velocity flow field and other dredge parameters such as suction intake diameter without the cutterhead and with a rotating cutterhead. This is useful to the dredging community for two reasons: first, knowing the region of influence around the cutterhead helps the dredger achieve higher production by using a more efficient cutting depth and second, achieving similitude with the velocity flow field allows for more accurate model testing in the future.
In order to help understand the more complex flow field around the cutterhead created by the cutting process, scenarios involving three different suction flow rates, three cutterhead rotation speeds, and two swing speeds, were investigated.
Prior studies of the flow field around the cutterhead provided a means to predict the velocity at the cutterhead intake. The flow field studies herein provide an extension into three dimensions as well as a verification of the previous results.
The highest velocities were found to occur nearest the cutterhead, specifically in the lower hemisphere of the cutterhead where the suction intake is located. The magnitude of these values greatly decreased with increasing distance from the cutterhead. In addition, the flow rate is shown to directly correlate to the velocity around the cutterhead.
It was found that the region of influence was nearly symmetrical around the cutterhead, but the shape could more accurately be described as an ellipsoid. The volumes of the regions of influence ranged from 10 ft^3 (0.283 m^3) to 80 ft^3 (2.27 m^3) for the model dredge and from 2,250 ft^3 (63.70 m^3) to 17,000 ft^3 (481.40 m^3).