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Rozprawy doktorskie na temat „Sediment transport”

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Autor: Grafiati

Data publikacji: 4 czerwca 2021

Data aktualizacji: 30 lipca 2024

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1

Sherwood, Christopher R. "Measurements and modeling of suspended-sediment transport on the northern California continental shelf /". Thesis, Connect to this title online; UW restricted, 1995. http://hdl.handle.net/1773/11014.

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2

Guerra, Josefa Varela. "Interannual variability of nearbed sediment flux and associated physical processes on the Eel River shelf, Northern California, USA /". Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/11000.

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3

Ghani, Aminuddin Ab. "Sediment transport in sewers". Thesis, University of Newcastle Upon Tyne, 1993. http://hdl.handle.net/10443/997.

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Sewers have been designed on the concept of self-cleansing where sediments are expected to move continuously without deposition. Due to the intermittent nature of the flow, deposition of solids in sewers could still occur especially at low flows such as during the receding flow or dry weather flow. The study of sediment movement in sewers will therefore need to cover both rigid (no-deposition) and loose (some deposition) boundary conditions. The present study extended the available data in rigid boundary conditions (clean pipes) to include the effects of surface roughness and pipe size. A complimentary study on the effect of sediment deposits (pipes with deposited beds) was also carried out. Extensive experiments on bed load transport of non-cohesive sediments without deposition were carried out in pipe channels of 154mm, 305mm and 450mm dia. covering wide -ranges of flow depths (0.15 < ya/D < 0.80), sediments (0.46 < dso (mm) < 8.3) and three different bed roughness values (0.0 < ko (mm) < 1.34). Supplementary data on transport over loose beds were collected in a 450mm dia. channel with various bed thicknesses up to 23% of pipe diameter. New transport equations based on all variables involved in the process were derived. Extensive uses of data from other relevant studies were made. The combination of the present and other data for both rigid and loose boundary conditions in pipes produced equations which could be applicable over wide range of conditions in sewers. A complimentary study on the rigid bed rectangular channels was also carried out. Using the newly derived equations, appraisals of the traditional concept of constant velocity criterion were made. The results show the inadequacy of the present design practice for diameters, pipe larger than 300mm. The comparisons made between the newly derived equations for rigid and loose boundaries in pipes suggest that sewers can be designed with clean inverts for diameters up to 1.0m while sewers with larger diameters should be designed allowing for an "optimum" depth of sediment deposits. Design charts based on the newly derived equations were devised.

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4

Fugate, David C. "Estuarine suspended aggregate dynamics and characteristics". W&M ScholarWorks, 2002. http://www.vims.edu/physical/projects/CHSD/publications/reports/F2002%5FPHD.pdf.

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5

Tomazoni, Julio Caetano. "O processo erosivo e o material hidro-transportado na bacia hidrográfica do rio Pinhal no Sudoeste do Paraná". Universidade Federal do Paraná, 1998. http://repositorio.utfpr.edu.br/jspui/handle/1/936.

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6

Wiberg, Patricia Louise. "Mechanics of bedload sediment transport /". Thesis, Connect to this title online; UW restricted, 1987. http://hdl.handle.net/1773/10988.

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7

Powell, David Newell. "Sediment transport upstream of orifices". Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1202498786/.

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8

Dick, Jennifer Ellen. "Sediment transport in oscillatory flow". Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235836.

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The effect of non-cohesive sediment on wave-induced bottom boundary layers was examined experimentally. Fluid velocity and sediment concentration were measured simultaneously in a sheet regime generated in a u-shaped oscillating water tunnel. A major obstacle to the understanding of fluid-grain flow has been the absence of suitable measuring devices. Thus, previous experimental investigations have been concerned primarily with low sediment concentration flows. For this study, a probe was developed to measure the instantaneous variations in sediment concentration based on the electrical conductivity of the fluid-grain mixture. Unlike earlier concentration devices, this probe is non-intrusive and is capable of measuring a wide range of sediment concentrations; from close packing within the bed to low concentration suspended load. Horizontal fluid velocities were measured simultaneously using Laser Doppler Anemometry in backscatter mode. Height and time-dependent velocity and concentration profiles were obtained for differing wave and sediment conditions. Values of the shear stress calculated from the momentum integral were found to be an order of magnitude larger than in sediment-free flows. The variation in shear stress with distance from the bed is clearly dependent on the thickness of the movable bed and also on the sediment flow regime. As expected, the eddy viscosity varied significantly during the wave cycle. The time-mean eddy viscosity decreases with height above the movable bed and at large distances from the bed, fluctuates about the mean. The sediment concentration measurements provide a comprehensive data set for sediment transport in sheet flow and near sheet flow regimes. The sediment concentration was found to be time-dependent with the amplitude and form of the temporal variation dependent on distance from the bed, wave amplitude and velocity, and sediment characteristics. With increasing wave amplitude and velocity, the number of peaks in the concentration profile increased while the magnitude of the peaks decreased. Fluid velocity and sediment concentration measurements were used to calculate rates of sediment transport which were compared with predictions from existing models.

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9

Kim, Hyoseob. "Three dimensional sediment transport model". Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359035.

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10

Dinsley, C. G. "Longshore sediment transport under waves". Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394685.

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11

Kuhail, Z. S. A. "Sediment transport in storm sewers". Thesis, University of Salford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234631.

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12

McIlhatton, Trevor D. "Sediment transport in combined sewers". Thesis, University of Liverpool, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414727.

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13

Mat, Suki R. B. "Sediment transport in storm sewers". Thesis, University of Salford, 1987. http://usir.salford.ac.uk/43025/.

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Literature survey made in this research indicated that the roughness has a significant effect on the design of a self-cleansing sewer. A conceptual model was therefore developed taking into account the effect of roughness in the sediment transport in sewers. This model was later tested against experimental data obtained from a test rig. The rig had a pipe which was specially fabricated in two halves so that it could be divided to coat the interior with uniform sand grains to provide roughness. The experimental data shows a good correlation with the model developed. Two relationships i.e. for smooth and rough pipes, were derived from the results. The effects of volumetric sediment concentration, pipe diameter, sediment size and effective roughness on these relationships were in turn examined. Head loss formulae acquired by past researchers were slightly modified to suit the range covered by the experimental data. The relationships developed in this research were subsequently applied to sewer design. These were later compared to the criterion of 0.76 m/s proposed by the British Standards. In the case of smooth pipes, it shows conclusively that the criterion of 0.76 m/s produces excessive slopes for pipe diameter up to 1.0 metre. However, for rough pipes the criterion gives insufficient slopes to maintain a self-cleansing sewer. This is valid up to a pipe diameter of 0.3 metre. Beyond this diameter the criterion gives high slopes. Comparisons were also made with studies in the wider field of sediment transport on fixed bed. These have set in context the proposed formulae for smooth and rough pipes in the design of storm sewers.

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14

Rowley, Kyle Jay. "Sediment Transport Conditions Near Culverts". BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4252.

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Relatively little work has been done to understand how coarse grained sediments behave near culverts. Particularly for embedded culverts, sediment transport must be understood to achieve sustainable culvert designs for aquatic organism passage and peak discharge requirements. Several culvert sites in the Wasatch Mountains of Utah were studied through the spring flood season of 2014. Data obtained from the culvert sites were used to create numerical models with the Sedimentation and River Hydraulics Two-Dimensional model. The field sites and numerical model were used to study deposition of sediments at the entrance to culverts, sediment replenishment inside culverts, and lateral fining within the culvert barrel. Each element of the study was observed in the field. It was shown that the Sedimentation and River Hydraulics Two-Dimensional model is a useful tool to simulate the observed phenomenon of sediment deposition upstream of culverts, sediment replenishment, and lateral fining. Sedimentation and River Hydraulics Two-Dimensional model should be used in culvert design procedures as a means to understand sediment transport conditions.This work documents the first time that deposition of sediments upstream of a culvert and lateral fining within a culvert barrel have been successfully modeled. The work shows that culvert replenishment occurs naturally in many scenarios and should be simulated as part of the culvert design process. The results from this work will be useful for future design guidelines for culvert installations.

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15

Denys, Frank. "Transverse transport of suspended sediment across the main channel - floodplain shear boundary /". Link to the online version, 2007. http://hdl.handle.net/10019/415.

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16

Battisto, Grace M. "Field Measurement of Mixed Grain Size Suspension in the Nearshore Under Waves". W&M ScholarWorks, 2000. http://web.vims.edu/library/Theses/Battisto00.pdf.

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17

Olli, Gull. "Waterborne sediment and pollutant transport into lakes and accumulation in lake sediments /". Stockholm : Department of Physical Geography and Quaternary Geology, Stockholm University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8302.

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18

Faries, Joseph W. C. "A new conductivity sediment concentration profiler (CCP) for the measurement of nearbed sediment concentrations application in the swash zone on a laboratory beach /". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 150 p, 2009. http://proquest.umi.com/pqdweb?did=1889078541&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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19

Guo, Qingchao. "Numerical modeling of suspended sediment transport". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0019/NQ54671.pdf.

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20

Shanehsazzadeh, Ahmad. "Swash zone hydrodynamics and sediment transport". Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406464.

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21

Leadbetter, Adam Marc. "Sediment transport in mixed marine environments". Thesis, University of East Anglia, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429678.

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22

Mayerle, Roberto. "Sediment transport in rigid boundary layers". Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294349.

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23

Lee, Jeng-Jong. "Contaminated sediment transport in Boston Harbor". Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/26825.

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24

Son, Minwoo. "Flocculation and transport of cohesive sediment". [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0041095.

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25

Gällstedt, Frida. "Transport av förorenat sediment i Eskilstunaån". Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-392763.

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Eskilstuna har sedan länge varit en industristad vilket har inneburit utsläpp av främst metallföroreningar men även organiska ämnen till Eskilstunaån. Provtagningar har vid upprepade tillfällen gjorts och det har visats att sedimentet i ån innehåller höga halter av förorenande ämnen. Sediment förorenat av miljögifter utgör en risk för både miljön och människors hälsa. Beroende på vilka förhållanden som råder i vattendraget skiljer sig sedimentationshastigheten åt, dels mellan olika vattendrag men den kan också variera inom recipienten vilket gör att det kan finnas särskilda områden där sediment och föroreningar ackumuleras. Det kan vara av vikt att identifiera dessa platser för att minska risken för återsuspension av sedimentet, som sedan kan transporteras vidare nedströms, samt för eventuella framtida åtgärder. I examensarbetet undersöktes föroreningsspridningen i Eskilstunaån och var ackumulationsbottnar kan förväntas ligga. En sedimenttransportmodell byggdes upp i programmet HEC-RAS med åns batymetri som utgångspunkt. Resultaten från modelleringar analyserades och tolkades med det geografiska informationssystemet ArcGIS och jämfördes med bottens hårdhet samt tidigare utförda sedimentprovtagningar. Sedimenttransportmodelleringen tyder på att området med mest ackumulation finns i Eskilstunaån där den passerar centrum och där åns botten är relativt mjuk. De högsta halterna för majoriteten av de undersökta metallföroreningarna påträffades trots detta längre nedströms där botten, sett till hela ån, inte var utmärkande mjuk men i jämförelse med närliggande platser var den däremot mjuk och relativt djup. En slutsats som kan dras ur detta är att vid lokalisering av ackumulationsbottnar bör vattendragets batymetri analyseras i kombination med bottens hårdhet och det bör göras på kortare sträckor.
Eskilstuna has been an industrial town for a long time which has caused emissions of mostly metal contaminants but also organic substances in to the Eskilstuna river. Samples from the sediment shows high content of some pollutants. Contaminated sediments can cause environmental and health hazards. Therefore, it is of importance to locate accumulation areas in the riverbed to avoid resuspension of the sediment, for preventing further transport downstream, and it may be of use if remediation measures becomes necessary. In this thesis the distribution of metal contaminants in the Eskilstuna river were investigated and accumulation areas located. A sediment transport model, based on the bathymetry, was implemented in the river analysis system HEC-RAS. The results from the model were later analyzed in the geographical information system ArcGIS and compared to the riverbeds hardness and the sediment samples. The sediment transport model showed an accumulation area in the river where it flows through the city center and the riverbed is relatively soft. The highest concentrations of most pollutants were found further downstream where the riverbed has a higher relative hardness. However, if only the neighbouring areas are compared to this locations the accumulation area is soft with a relative large depth. As a conclusion, one may have to take both bathymetry and the riverbeds hardness into account when locating accumulation areas.

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26

Goodridge, Wade H. "Sediment Transport Impacts Upon Culvert Hydraulics". DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/416.

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Sedimentation buildup and accumulation can cause serious impediments to the hydraulic capacity of culvert systems. There has not been any significant research to date regarding the behavior of bed load transport nor the implications of bed forms upon the hydraulics associated with culvert flow. The primary objective of this study was to investigate how sediment transport occurs in a culvert and to then develop a methodology and test setup to successfully investigate this sediment transport. The investigation was limited to studying culvert and pipeline transport of alluvial material in sand and gravel sizes. This dissertation develops a semi-empirical bed load transport equation from existing open channel flow models to be used in predicting sediment yields in culvert applications. Incipient motion and critical shear stresses were investigated for application into eight empirically based models. The methods analyzed include the Meyer-Peter Müller, Engelund and Hansen, Shields, Toffaleti (as seen in the United States Army Corps of Engineers program HEC RAS), Schoklitsch, DuBoy, Yang, and Rottner methods. These methods were tested for predictive accuracy to physically modeled bed load transport data obtained from a 304.8 mm (11.89 in) diameter culvert. Tests involved fully pressurized, partially pressurized inlet controlled, and open channel flow regimes for a variety of bed elevations and bedforms. Bedform regime and associated resistance impacts on flow energy were presented to better understand their hydraulic consequence in culvert applications. An extensive literature review regarding sediment transport in both open channel and closed conduit applications is provided to develop a foundation of knowledge to pursue further research in this area. This literature review summarizes the current body of scientific knowledge that is applicable to sediment transport in culverts. Investigations into both historical and current works are cited throughout this studies literature review. A tested methodology is presented for the investigation of sediment bed load transport in culvert applications. Development of a procedure for the testing of critical shear limits and bed load transport is outlined. A detailed application example is provided. Recommended changes in testing techniques and physical model are made for the next generation of culvert sediment transport research.

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27

Joo, Marianna. "Evaluation of Sediment Transport Formulas for Queensland Rivers". Thesis, Griffith University, 2008. http://hdl.handle.net/10072/367936.

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Measurement and prediction of sediment transport rates are important for rivers in Queensland, particularly in connection to sediment delivery to near shore lagoons in the Great Barrier Reef. Planning and managing for sustainable sand and gravel extraction also requires accurate and reliable calculation of bed material load in river systems. Using sediment transport formulas can overcome the difficulties and reduce the costs associated with collecting field data. Sediment transport formulas were developed from theories that relate sediment transport to hydraulic and sediment variables, and were calibrated mostly with laboratory experiments. Previous evaluations of these formulas, mostly under the US and European conditions, showed that the suitability of these formulas could vary greatly according to the flow conditions under which they were applied. Evaluating the formulas in Australia is virtuallly nonexistent. In this study, sediment transport formulas are evaluated for Queensland rivers, where a wide range of climatic, hydrological and sediment conditions exist.
Thesis (Masters)
Master of Philosophy (MPhil)
Griffith School of Engineering
Science, Environment, Engineering and Technology
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28

Arthur, Scott. "Near bed solids transport in combined sewers". Thesis, University of Abertay Dundee, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309761.

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29

Khalid, M. (Muhammad). "Erosion of organic sediments and modelling of sediment transport in peat drainage area". Master's thesis, University of Oulu, 2015. http://urn.fi/URN:NBN:fi:oulu-201502131085.

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Detailed knowledge from physical properties of sediment such as erosion and settling velocity are crucial for modelling as well as for water protection planning and management. The main purpose of this research was to determine the critical shear stress (τcr) and settling velocity of the organic sediments in different peatland drainage areas and headwaters in Finland. Further, KINEROS2 erosion model was applied to peatland forestry and peat extraction conditions to simulate runoff hydrograph and suspended solid yield from two experimental catchments. To determine mean τcr and settling velocity totally 119 undisturbed sediment samples were taken from the natural streams, ditches and brooks across Finland. The samples covered main peatland uses, peatland forestry and peat extraction sites. Furthermore, to determine the effect of peat soil properties on sediment erosion and settling, peat soil samples were collected from 9 peat extraction areas. These samples were used to prepare sediments in laboratory setting. Cohesive strength meter (CSM) was applied to measure the τcr and settling velocity in laboratory and in-situ conditions. Results were compared against physical properties of sediment or peat soils and further compared against different peatland uses. The critical shear stress over all samples ranged from 0.0057 to 0.428 N m⁻² (mean value 0.116 ± 0.07 N m⁻²). τcr in peatland forestry ditches ranged from 0.0057 to 0.428 N m⁻² (mean value 0.07 ± 0.1 N m⁻²), and in peat extraction sites from 0.006 to 0.421 N m⁻² (mean value 0.12 ± 0.06 N m⁻²). Similarly, τcr of artificially prepared samples from peat extraction area ranged from 0.012 to 0.112 N m⁻² (mean value of 0.059 ± 0.028 N m⁻²). At Koivupuro peatland forestry site, measurements were done in laboratory as well as in-situ. Results gave slightly different values; in-situ τcr ranged from 0.005 to 0.305 N m⁻² with the mean value of 0.03 ± 0.075 N m⁻², and the laboratory results ranged from 0.008 to 0.310 N m⁻² with the mean value of 0.125 ± 0.06 N m⁻². Degree of humification (DOH) and dry bulk density were found to be positively related to critical shear stress. The settling velocity results for Koivupuro catchment ranged from 0.0004 to 0.131 m h⁻¹ (mean value 0.016 ± 0.034 m h⁻¹) and 0.0004 to 0.456 m h⁻¹ (mean value 0.144 ± 0.134 m h⁻¹) for other organic peat samples. Degree of humification (DOH) and settling velocity showed no correlation while dry density of settled sediment was found inversely proportional to settling velocity. This study showed that CSM can be used to determine τcr and settling velocity from organic sediment samples. Results can be applied in modelling purposes, and in dimensioning of water protection methods such as settling basins. Eleven rainfall-runoff events from two different catchments were selected for the study to simulate runoff hydrographs and associated sediment yields in different conditions. When properly calibrated for each event, KINEROS2 model produced sufficient estimations of runoff hydrographs for peatland forestry and peat extraction sites but failed to produce reliable estimations of suspended sediment yields. Moreover, unrealistic parameter values sometimes had to be used in model calibration due to model inability to simulate groundwater or soil water response in ditch flow. Thus the model could not be validated for varying initial conditions and rainfall events.

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30

Mullenbach, Beth Lee. "Characterization of modern off-shelf sediment export on the Eel margin, Northern California /". Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/10969.

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31

Ros, i. Sala Àlex. "Effects of aquatic vegetation on sediment transport". Doctoral thesis, Universitat de Girona, 2016. http://hdl.handle.net/10803/401629.

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In the margins of continents there are the coastal zones, regions of remarkable biological productivity. Coastal zones include, among others, wetlands, that are land areas inundated permanently o seasonally, characterized by the presence of aquatic vegetation adapted to the hydric soil. Therefore it is necessary to consider the effect of aquatic canopies in wetlands investigations. These areas are governed by physical forces originated from tidal currents, waves, winds, night convection and floods. The aim of this thesis is to study the sediment transport in wetlands in which fluid is dominated by a) progressive waves, b) nearly isotropic turbulence and c) extreme flooding events
Als marges dels continents hi ha les zones costaneres, regions d’altra productivitat biològica. Les zones costaneres inclouen, entre d’altres, els aiguamolls, que són zones terrestres inundades permanentment o estacionalment, caracteritzades per la presència de vegetació aquàtica adaptada a sols hídrics. És per tant necessari considerar l’efecte de les praderies aquàtiques en les investigacions en aiguamolls. Aquestes àrees estan governades per forces físiques originades per corrents de marees, ones, vent, conveccions nocturnes i inundacions. L’objectiu d’aquesta tesi és estudiar el transport de sediments en aiguamolls on el fluid és dominat per a) ones progressives, b) turbulència gairebé isòtropa i c) inundacions extremes

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32

Frings, Roy. "From gravel to sand : downstream fining of bed sediments in the lower river Rhine /". Utrecht : Koninklijk Nederlands Aardrijkskundig Genootschap, Faculteit Geowetenschappen, Universiteit Utrecht, 2007. http://www.loc.gov/catdir/toc/fy0804/2008400397.html.

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33

Lee, Guan-hong. "Across-shelf sediment transport modeling and its application to storms at Duck, North Carolina". W&M ScholarWorks, 2000. http://www.vims.edu/physical/projects/CHSD/publications/reports/L2000%5FPHD.pdf.

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34

Piqué, Altés Gemma. "Analysis of hydro-sedimentary processes and impacts affecting river basins and channels". Doctoral thesis, Universitat de Lleida, 2017. http://hdl.handle.net/10803/405448.

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Aquesta tesi estudia la dinàmica hidro-sedimentària de rius mediterranis, tant ‘naturals’ com regulats per preses. Amb aquest objectiu, s’ha realizat un estudi a escala multi-temporal i multi-espacial, que inclou treball de camp en trams de riu representatius, l’anàlisi de dades a nivell de conca, i experiments en canals de laboratori. L’alteració hidrològica aigües avall dels embassaments s’ha observat a diferents escales temporals, afectant notablement la magnitud i freqüència de les crescudes. A nivell sedimentari, s’observa un dèficit de sediments, fet que facilita l’establiment de biofilm i que, a la vegada, afavoreix l’estabilització del llit del riu. A més, l’emmagatzematge temporal de sediments a la llera modula el balanç i regula l’entrada de sediments en embassaments. La tesi mostra els efectes d’un conjunt d’activitats antròpiques en procesos fluvials i com això altera les interaccions bio-físiques del riu, i posa èmfasi en la necessitat d’una gestió contínua per la preservació dels ecosistemes fluvials.
Esta tesis estudia la dinámica hidro-sedimentaria de ríos mediterráneos, tanto ‘naturales’ como regulados por presas. Con este objetivo, se ha realizado un estudio a escala multi-temporal y multi-espacial, que incluye trabajo de campo en tramos de río representativos, análisis de datos a nivel de cuenca, y experimentos en canales de laboratorio. La alteración hidrológica aguas abajo de los embalses se ha observado a diferentes escalas temporales, afectando notablemente la magnitud y frecuencia de las crecidas. A nivel sedimentario, se observa un déficit de sedimentos, lo que facilita el establecimiento de biofilm y, a la vez, favorece la estabilización del lecho del río. Además, el almacenamiento temporal de sedimentos en el lecho modula el balance y regula la entrada de sedimentos en embalses. La tesis muestra los efectos de un conjunto de actividades antrópicas en procesos fluviales y en la alteración en las interacciones bio-físicas del río, y enfatiza la necesidad de una gestión continua para la preservación de los ecosistemas fluviales.
This PhD thesis studies hydro-sedimentary dynamics in Mediterranean rivers, both in ‘natural’ and in dammed rivers. For this purpose, a multi-temporal and spatial research was carried out, including field measurements in representative river reaches, data analysis at the basin scale, and experiments in artificial streams. The hydrological alteration downstream from dams was documented at different temporal scales, notably affecting the magnitude and frequency of floods. Regarding sediments, a severe deficit was observed below dams, a fact that facilitates the establishment of biofilm which, in turn, favours river bed stabilisation. Moreover, the study shows how in-channel storage influences the river sediment budget and regulates sediment input in reservoirs. The thesis examines the effects of a suit of human activities on fluvial processes and how this alter rivers’ bio-physical interactions, and emphasises the need of continuous monitoring of all these processes to achieve a sound management of fluvial ecosystems.

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Palinkas, Cynthia. "Temporal and spatial patterns of modern shelf sedimentation in the Adriatic Sea /". Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/10986.

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Teakle, Ian Alan Lester. "Coastal boundary layer and sediment transport modelling /". [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19317.pdf.

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Check, Lindsay A. (Lindsay Anne). "Analysis of Longshore Sediment Transport on Beaches". Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4886.

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The present study investigates longshore sediment transport for a variety of bathymetric and wave conditions using the National Oceanic Partnership Program (NOPP) NearCoM Model. The model is used to determine the effects of wave shape and bathymetry changes on the resulting longshore sediment transport. The wave drivers, REF/DIF 1 and REF/DIF S, are used to assess the effects of monochromatic and spectral waves on longshore sediment transport, respectively. SHORECIRC is used as the circulation module and four different sediment transport models are used. Longshore transport comparisons are made with and without skewed orbital velocities in the shear stress and current velocities. It is found that the addition of skewed orbital velocities in shear stress and transport formulations increases longshore sediment transport by increasing time-varying effective shear stress. The addition of skewed orbital velocities greatly increases the transport due to advection by waves. The localized longshore sediment transport is calculated using a generic physics based method and formulas by Bagnold, Bailard, and Bowen, Watanabe, and Ribberink. The transport results for each scenario are compared to the total transport CERC, Kamphuis, and GENESIS formulas. The bathymetries tested include an equilibrium beach profile, cusped beach profiles, and barred beach profiles with different bar locations. The longshore transport on an equilibrium beach profile is modeled for a 0.2 mm and 0.4 mm grain size and transport is compared to the CERC formula. The longshore sediment transport for d=0.2 mm is larger than d=0.4 mm when wave power is small, but as wave power increases the transport for the larger grain size dominates. The transport is also affected by the addition of cusps and bars on an equilibrium beach profile. The barred beach is modified to compare transport between waves breaking at the bar, before the bar, and after the bar. The features affect the transport when the wave powers are small, but as wave heights increase the cusp and bar features induce little change on the longshore sediment transport.

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El-Zaemey, Abdel Kaher Saeed. "Sediment transport over deposited beds in sewers". Thesis, University of Newcastle upon Tyne, 1991. http://hdl.handle.net/10443/3602.

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In sewer networks deposition of solids can occur from time to time, due to the intermittent nature of flow. The longer the deposits remain in sewer systems the more likely it is that the sediment properties will change. Eventually these depositions can become cemented (consolidated) especially during dry weather flow (DWF) when the boundary shear stress values are lower than the critical values and the velocity is not enough to carry the sediment along the sewers. The main objective of the present study was to highlight and cover the shortage of methods and approaches in understanding the nature of sediment transport problems in sewers with a build up of permanent deposits. Extensive experiments were carried out in a circular cross section channel (D=305 mm) with various fixed bed thicknesses namely 47 mm, 77 mm and 120 mm, and three different bed roughnesses (0.0

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Elfrink, Berry. "Longshore sediment transport in the swash zone /". Lyngby : Technical University of Denmark, 1996. http://www.gbv.de/dms/tib-ub-hannover/248475355.pdf.

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Reed, D. J. "Suspended sediment transport in salt marsh creeks". Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355891.

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Putri, Masdiwati Minati. "Hydraulic capacity of culverts under sediment transport". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for vann- og miljøteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25918.

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Sedimentation frequently causes an extensive blockage in culvert which may reduce its design capacity. Culvert guidelines which are extensively used reveal little details about sedimentation in culvert. Requirement of the design guidelines for culvert in steep terrain considering sediment transport condition implies the necessity of the culvert guidelines development. Two prior studies of culvert performance on steep terrain have been conducted. The first study evaluated the effects of expansion section length on the performance of the culvert under jet regime, while the other one investigated the effects of additional roughness installed on the model which then changed the flow regime of the model.Several laboratory experiments have been conducted during this study. The main focus of the study is to investigate the influence of the width of expansion section on the performance of the culvert. Tests were conducted on the scaled model which represents a culvert in a steep terrain. The model is designed for inlet control focusing only on a circular pipe, which consists of an upstream reservoir, an approach channel, and a channel expansion section. Streams on the model are supercritical at the approach channel and subcritical at the expansion section. The experiments simulated performances of the culvert under clear water and sediment transport conditions. The experimental phase was performed with three different inlet setups in various widths of expansion section. In the sediment transport experiments, various sizes and amount of sediments were used and combined with different methods of feeding the sediments. Flow pattern, sediment efficiency, and sediment deposition pattern were observed on the experimental works. The results of the experiments are shown through the inlet control performance curve which represents the ratio of the water depth to the culvert barrel diameter as a function of dimensionless discharge.As the main result, the performance of the culvert under clear water and sediment transport conditions is influenced by the width of expansion section and the inlet setup. In general, narrower width develops better culvert performance. The amount of sediment deposited in the expansion section and its deposition pattern are associated with the phenomena that occur on flows as a result of the expansion section widths effects.

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Carrie, A. L. S. "Wave refraction modelling and longshore sediment transport". Thesis, University of East Anglia, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372553.

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Voulgaris, George. "Suspended sediment transport in the littoral zone". Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385504.

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Wilcock, Peter R. (Peter Richard) 1953. "Bed-load transport of mixed-size sediment". Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14866.

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MacDonald, R. G. "Flow and sediment transport at hydraulic jumps". Thesis, University of East Anglia, 2010. https://ueaeprints.uea.ac.uk/20506/.

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Beck, Julia S. "Sediment transport dynamics in South African estuaries". Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/1465.

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Thesis (PhD (Civil Engineering))--University of Stellenbosch, 2005.
Estuaries are complex water bodies and differ considerably from fluvial river systems. In estuaries the flow reverses regularly due to the tidal currents and flow depths depend primarily on the tides and not the flow. An estuary has two sources of sediment: the river during floods and the ocean that supplies marine sediment through littoral drift which is transported by tidal currents into the estuary. Oversimplified models cannot be used to investigate the hydrodynamics and geomorphology of an estuary due to its complexity. Sedimentation of South African estuaries has created several environmental and social problems. Sediment transport imbalances have been caused by changes in the river catchments such as increased sediment yields and flood peak attenuation due to dam construction. Historically floods used to flush estuaries to maintain the long-term sediment balance in the river-estuary system, but with reduced flood peaks, sediment transport capacities at the estuaries are reduced and flushing efficiency decreased, resulting in marine transport dominating in many estuaries. Two-dimensional (horizontal, 2DH) numerical models have been found to be appropriate tools for studying hydro- and sediment dynamics in SA estuaries. The modelling shows that the sediment balance in the estuary relies on a delicate balance between dominant flood and ebb flows. Although the models performed very well, there are still additional processes to include such as time varying roughness changes and cohesive sediments. For long-term and long reach simulations, onedimensional (or quasi-two-dimensional) models will also be required in future. Mathematical modeling can be used to simulate the flushing of sediments during floods, but attempts should be made to calibrate these models when adequate field data become available in the future. The modelling has shown that floods play a very important part in estuarine sediment transport processes. Physical modelling was undertaken of the breaching of an estuary mouth. The main aim was to illustrate the merits of breaching at higher water levels as well as to investigate the changes in the mouth during breaching. The data obtained from the experiments were used to calibrate and verify a mathematical model. Mathematical modelling of the breaching process at the Klein River estuary confirms what has been observed during numerous breachings in the field, i.e. that breaching at higher water levels and towards the southeast side is more effective. Sediment transport by both waves and currents was investigated. It was found that with increasing wave and stream power, sediment transport rates would increase if both waves and currents travelled in the same direction. In contrast, it seems that with the current direction opposing that of the waves, Hydraulics of Estuarine Sediment Transport Dynamics in South Africa iii greater wave heights resulted in lower sediment transport rates. A new sediment transport equation, based on stream power, wave power, as well as sediment size was calibrated and verified, and compared to the well-known Bijker formula.

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Mayne, David A. "Finite element modelling of cohesive sediment transport". Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/15300.

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The movement of cohesive sediment is of great importance in many coastal and estuarine engineering problems. Navigation channels often used to be dredged to maintain navigable depths, allowing for the effect of a harbour or wharf on the local sediment transport regime. Contaminants are readily absorbed by silt and clay particles, causing a range of water quality problems. This thesis describes the development and testing of a finite element program to model cohesive sediment transport. The program solves the coupled Navier-Stokes and scalar-transport equations along with several complex numerical algorithms for settling velocity, flocculation, non-Newtonian flow and turbulence. The program also uses h-adaptivity and unstructured mesh generation to capture important flow features. The program is benchmarked against the thermally driven cavity problem, producing results that compare well with existing solutions without any special scheme for advection dominated flow. This is possible by modelling the transient problem using h-adaptivity. The programme is also applied to realistic cohesive sediment transport problems. It predicts the formation of a hindered settling layer and uses h-adaptivity to capture sharp density interfaces. It also solves settling of dredged material onto a inclined bed and non-Newtonian flow in a race-track flume. The program produces results that compare well with experimental data. The h-adaptive finite element method is found to be a very successful in modelling the transport of cohesive sediment and its associated physical processes.

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Venn, J. F. "Shallow sea tidal friction and sediment transport". Thesis, London Metropolitan University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238297.

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Rice, M. Ann. "Grain shape effects on aeolian sediment transport". Thesis, University of Aberdeen, 1990. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602267.

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Particle shape is a parameter which has been largely neglected in the study of sediment transport by wind. Many methods of measuring shape have been published. Those which characterize shape in pebble and sand sized sediments are reviewed here. In order to test the influence of shape on aspects of particle movement and on sediment transport rate, two very differently shaped populations were used, (a) a reasonably equant quartz dune sand and (b) a platy dune sand composed largely of shell fragments. Recommendations are made for reasonably fast and accurate methods of shape measurement, including Sneed and Folk's Maximum Projection Sphericity and Winklemolen's Rollability. The possible effects of shape on saltation were examined in terms of grain trajectories and the grain's interaction with the bed at collision using video and high speed photography. The latter enabled individual particles (from a coarse, medium or fine size fraction) to be followed as they impacted the bed, through to ricochet and the possible ejection of previously stationary bed grains. Experiments were conducted over horizontal and sloping beds, the latter representing different parts of the stoss face of a ripple. It was found that shape, in terms of the sphericity of the particles has a marked effect on collision. The near spherical quartz sand causes more dislodgements and more ejecta per collision than the much less spherical platy shell sand. The quartz sand is also more likely to approach and ricochet from the bed at higher angles to the horizontal than the shelly sand, and to rebound more vigorously. Thus, the bed activity generated by collision increases with an increase in particle sphericity. However, high speed photography of grain dislodgement by wind action alone indicates that, as sphericity decreases, there is a greater probability that a grain will be entrained aerodynamically. Shape also influences trajectories. Video films show that grain paths become longer and flatter as sphericity decreases. These observations indicate that the transport rate for grains with a low sphericity will be greater than those with a high sphericity, both in terms of aerodynamic entrainment and of longer trajectories. However, once collision becomes important in the dislodgement of surface grains, the greater bed activity seen with more spherical particles means that their transport rate will increase. These findings are supported by the observations of Williams (1964) and of Willetts, Rice and Swaine (1982), that sediment transport is promoted at low windspeeds by less spherical grains, while the opposite occurs at high windspeeds.

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Alkhalidi, Mohamad. "Sediment transport in sandy estuaries at equilibrium". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010108.

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