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1
Gouw, Marc Jean Pierre. "Alluvial architecture of the Holocene Rhine-Meuse delta (The Netherlands) and the Lower Mississippi Valley (U.S.A.) /." Utrecht : Koninklijk Nederlands Aardrijkskundig Genootschap [u.a.], 2007. http://www.loc.gov/catdir/toc/fy0803/2008400359.html.
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Schmidt, Armin R., and H. Fazeli. "Tepe Ghabristan: A Chalcolithic tell buried in alluvium." Wiley, 2007. http://hdl.handle.net/10454/4024.
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noThe Chalcolithic tell of Ghabristan in northwest Iran is now buried by alluvium and a magnetometer survey of the tell and its surroundings was undertaken to reveal any features under this cover. After the abandonment of the tell in the late third millennium BC it was used as an Iron Age cemetery by inhabitants of the neighbouring tell of Sagzabad. The magnetometer data show a related irregularly shaped channel that is also considered to be of Iron Age date.Its shallow burial depth, compared with the thick sedimentary layers underneath, indicates a considerable slowdown of alluviation rates in the second millennium BC, possibly related to environmental changes. The survey also found evidence for undisturbed buried building remains, most likely associated with copper workshops.
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Glaser, Danney R. Lee Jejung. "Estimation of alluvium properties from spectral induced polarization measurements." Diss., UMK access, 2007.
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Thesis (M.S.)--Dept. of Geosciences. University of Missouri--Kansas City, 2007."A thesis in urban environment geology." Typescript. Advisor: Jejung Lee. Vita. Title from "catalog record" of the print edition Description based on contents viewed Dec. 18, 2007. Includes bibliographical references (leaves 105-112). Online version of the print edition.
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Sargent, Paul. "Secondary minerals to replace cement in stabilising an alluvium." Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/2892.
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Ordinary Portland cement (CEM-I) is widely used across the construction industry. It is the most commonly used cementitious binder for ground improvement applications such as deep dry soil mixing (DDSM) in the UK, due to its high strength performances. However, CEM-I production is one of the world’s most energy intensive and expensive industrial processes; contributing up to 7% of the world’s total CO2 emissions (McLellan et al., 2011). Hence, there is now significant pressure on the cement and construction industries to greatly reduce their CO2 emissions by developing “greener” alternatives to CEM-I, which are both more environmentally and financially sustainable in the long-term. Alkali activated industrial waste materials, known as geopolymers have been identified as potential alternatives to CEM-I. There are numerous advantages in recycling industrial waste materials such as ground granulated blast furnace slag (GGBS) and pulverised fly ash (PFA), including avoiding the need to transfer such materials to landfill, their abundant supply, negligible or zero production costs and for calcium-bearing wastes such as slags, their recently determined potential for carbon capture and storage (CCS). This thesis presents recent laboratory research which focussed on the potential for utilising alkali activated industrial waste materials as sustainable binders in DDSM to enhance the geotechnical properties of soft soils. The laboratory testing programme deployed geotechnical and mineralogical tests to determine the performance of the binders when incorporated into a soft alluvial soil, typically found in abundance across the UK. Comparisons with the strength and durability of untreated and stabilised soils have been made. The study indicates that from the by-products tested, soils stabilised with sodium hydroxide (NaOH) activated GGBS resulted in the greatest strength and durability improvements; with other materials tested showing smaller improvements. The addition of NaOH has been observed to allow pozzolanic reactions to occur, leading to improved mechanical properties; primarily strength, which increased with time. Abstract Secondary Minerals to Replace Cement in Stabilising an Alluvium ii The effectiveness of DDSM treatment in stabilising sections of high-speed railway lines with ground conditions dominated by soft and highly compressible soils, has previously been well demonstrated (Holm et al., 2002; Hughes and Glendinning, 2004). Traditionally, the monotonic strength properties of stabilised soils have been used to assess their suitability for stabilising railway embankments. However, the dynamic strength properties of such materials require investigation in order to provide better estimates of their field behaviour when subjected to complex loading conditions associated with high-speed railway embankments and high-frequency train traffic. Hence, this thesis combines monotonic and dynamic triaxial testing techniques to assess the suitability of the new GGBS-NaOH binder for stabilising high-speed railway embankments. After 28 days curing, the binder successfully demonstrated itself as an effective countermeasure against significant track displacements after the simulated passage of a typical InterCity 125 high-speed train. This thesis advocates that there is great potential for using GGBS-NaOH as a more environmentally and financially sustainable binder over CEM-I for DDSM projects in the UK, such as the proposed HS2 and HS3 rail links. However, further research and collaboration with the construction industry is still required before the new binder may be used on a commercial scale.
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Gould, Simon R. "Integrated sedimentological and whole-rock trace element geochemical correlation of alluvial red-bed sequences at outcrop and in the subsurface." Thesis, University of Aberdeen, 2001. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230625.
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Red-bed alluvial systems are becoming increasingly important as hydrocarbon plays in the UK Northern North Sea. Commonly such ephemeral systems are hard to define in terms of reservoir architecture, due to the difficulty in correlating such diverse and palaeontologically-barren sequences. This project aims to improve understanding of one such system, the Late Jurassic Cormorant Formation, of the Northern North Sea, through detailed sedimentological study of two outcrop analogues. The whole-rock trace element geochemical correlation technique in a variety of settings. The Lower Old Red Sandstone Moor Cliffs Formation of the Anglo-Welsh Basin provides ideal conditions for testing the whole-rock trace element geochemical correlation technique. The Moor Cliffs Formation is a low net:gross alluvial red bed suite, which by virtue of Variscan deformation, outcrops in a well-exposed, easily accessible cliff section at Priests Nose, near Manorbier, Pembrokeshire. A 100m section was sampled to determine variables that may affect whole-rock trace element geochemical correlation. The results prove that whole-rock trace element geochemical correlation can be applied to alluvial successions, despite pedogenic modification and deep burial. The Late Triassic Blomidon Formation of the Fundy Basin, Nova Scotia, provided a second outcrop example of an alluvial red-bed sequence, which was deposited in similar palaeo-climatic and tectonic conditions to the Northem North Sea Triassic. The Blomidon Formation contained a range of fluvial styles from confined channels to unconfined sheetfloods. Three sections were studied along the hanging-wall margin of the Fundy Basin, separated by up to 150km along strike. Each section provided a contrasting basinal setting, allowing comparison of facies along strike and down depositional dip. Sections were measured in detail to quantify bed geometries and facies variants, facilitating architectural analysis. Specific attention was paid to features that may be diagnostic in sub-surface cored sections of the Northern North Sea Triassic. Correlation was possible on a number of scales, using laterally continuous ephemeral marker beds within the Blomidon Formation. Detailed facies evaluation has allowed the division of the Blomidon Formation into four distinctive facies packages that vary considerably in sandstone net:gross. Each facies assemblage is defined by variations in fluvial style and occurrence of evaporite rich, ephemeral lacustrine and rare aeolian sediments. It was possible to produce a broad, basin-wide correlation scheme for the Blomidon Formation, based on these four facies packages. Detailed facies analysis of three cores from the Cormorant Formation, Tem Field, Northern North Sea allowed definition of reservoir architecture, based on models derived from outcrop analogues. The results suggest that correlation based on individual horizons and facies packages is possible in alluvial red-bed sequences through detailed sedimentological study. The whole-rock trace element geochemical correlation technique can also provide additional datasets to enhance correlation in the subsurface.
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Abbott, James T. "Late Quaternary alluviation and soil erosion in Southern Italy /." Digital version accessible at:, 1997. http://wwwlib.umi.com/cr/utexas/main.
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CHADWICK, OLIVER AUSTIN. "INCIPIENT SILICA CEMENTATION IN CENTRAL NEVADA ALLUVIAL SOILS INFLUENCED BY TEPHRA (DURIPAN, TAXONOMY, OPAL-CT, GENESIS)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187945.
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Silica cemented pedogenic horizons known as duripans occur on relict landforms in climates having limited leaching potential. Under the influence of tephra, incipient silica cementation may also occur in late Quaternary soils. The source of silica for cementation in Holocene soils is rapidly weatherable volcanic glass. In response to wetting and drying cycles volcanic glass weathers to form sand-size composite particles composed of silt, clay and redeposited silica. A portion of the hydrolyzed silica is eluviated as monosilicic acid which accumulates as the wetting front evaporates. Illuvial silica augments existing composite particles eventually forming a continuously cemented duripan. In actively forming late Quaternary soils, the cementation process is a complex interaction between illuvial silica, clay and calcium carbonate and the soil matrix. Surface reactions between monosilicic acid and illuvial clay or soil matrix particles provide nucleation sites for polymerization of silica concentrated by evaporation. The resulting opaline silica bonds adjacent soil grains without necessarily plugging intervening pore spaces. In contrast, calcium carbonate preferentially precipitates in large pores and interped voids. Cementation occurs by the plugging of progressively smaller pores with relatively pure calcite rather than by heterogeneous bonding of mineral grains. In illuvial zones containing both silica and calcium carbonate, cementation may occur rapidly because the former holds small soil particles in place while the latter plugs large pores. The mineralogy of silica cement is determined by identification of varying amounts of crystal order using X-ray diffraction. Opal-A is recently polymerized, noncrystalline, highly hydrated silica gel. The more prevalent, partly crystalline opal-CT forms where surface reaction with clays create crystal orientation, where silica gel dehydrates or when silica precipitates from soil solutions having high concentrations.
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Nikolinakou, Maria-Aikaterini 1976. "A constitutive model for the compression behavior of Old Alluvium." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44291.
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Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.Includes bibliographical references.
Old Alluvium is classified as a transported, in-situ weathered tropical soil, and represents a class of geomaterials that have a complex microstructure, including cemented aggregates at the meso-scale and groups of clay stacks at the micro-scale. Despite the presence of significant fractions of nontronite (smectite species), the activity of charged clay particles is initially masked by the aggregation of iron oxides. Compression loading breaks the cementation at the meso-scale and causes physico-chemical changes at the micro-scale, which reveal the expansive characteristics of the clay minerals. It is difficult to achieve a fully disaggregated condition (through mechanical mixing or selective chemical dissolution) and hence, there is little practical value in referencing properties of the intact soil to a hypothetical disaggregated or intrinsic state as proposed for other bonded soils. The proposed formulation describes the variation of compressibility according to a measure of the microstructural changes using the Cation Exchange Capacity as a state variable. Upon load reversal, a model based on double layer theory is integrated to predict macroscopic volumetric expansion due to the swelling of the nontronitic clay fraction. This behavior is also linked to the Cation Exchange Capacity through the preconsolidation stress level, and hence, can accommodate changes in the clay swelling potential caused by mechanical or physicochemical loading. The model parameters depend on the compression characteristics of the intact soil, on measurements of the Cation Exchange Capacity in the intact and partially disaggregated states, on the amount of expandable minerals in the microstructure and on the initial hydration of the clay stacks.
(cont.) Overall, the proposed formulation introduces a new way of modeling the compression of bonded materials with evolving microstructural characteristics, which does not require a unique reference state. It builds the swelling response directly on the physicochemical characteristics of the soil. The thesis also includes an experimental program on block samples obtained from a tunneling project in San Juan, Puerto Rico. The laboratory data was used for the calibration and detailed validation of model predictions. The proposed formulation enables predictions of expected engineering properties through the vertical weathering profile of the Old Alluvium.
by Maria-Aikaterini Nikolinakou.
Sc.D.
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Narbett, Robert Wyn. "Geological and engineering properties of estuarine alluvium from the Severn Estuary." Thesis, University of Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243694.
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Youngson, John Hughan, and n/a. "Physical and chemical processes affecting the formation of alluvial gold deposits in Central Otago, New Zealand." University of Otago. Department of Geology, 2007. http://adt.otago.ac.nz./public/adt-NZDU20071108.160736.
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Alluvial gold placers in Otago and northern Southland occur at several stratigraphic horizons within the Late Cretaceous - Recent sedimentary sequence. The gold is derived ultimately from primary sources in the Otago Schist. Poor correlation between the distribution of placers and that of the known primary deposits reflects repeated recycling of gold in the present drainage network and two precursor networks, each with substantially different architecture. The previous drainage networks were inundated and buried during marine or lacustrine transgression. There has been local addition of first cycle gold and immature detritus during each recycling phase.
Most of the placer deposits are fluvial in origin but colluvial placers occur locally along the margins of several Central Otago ranges. Aeolian placers and marine placers are rare. Most of the gold in placers north of the Caples/Torlesse Terrane boundary is Au-Ag alloy, except in vicinity of the Hyde-Macraes Shear Zone, where α-Au-Ag-Hg alloy is also present. Conversely, α-Au-Ag-Hg alloy dominates in placers south of the Caples/Torlesse Terrane boundary, except those whose headwaters lie, or lay, in the Torlesse Terrane. These systems that cross the terrane boundary contain Au-Ag and Au-Ag-Hg alloys in the reach downstream of the boundary, and placers with their source in Aspiring Lithologic Association also contain both alloys. Textural and compositional maturity of the placer host generally increase with decreasing age, reach maxima at the Waipounamu Erosion Surface, and generally decrease in tandem with age above this surface. Exceptions occur in northern Southland, where quartz pebble conglomerate placers are actively forming.
Fluvial quartz pebble conglomerate placers have not formed in a single sedimentary cycle. Instead, they have formed from precursor sediment where a high water table drives alteration of the labile component, and when uplift and erosion rates, topography and stream gradients are all sufficiently low to drive sedimentary recycling without significant input of low-grade basement detritus. The maturity of pre-marine examples (Taratu, Papakaio and Hogburn Formations) was enhanced by wave-reworking before final inundation during marine transgression. Colluvial placers in alluvial fans at the margins of Quaternary schist antiforms are repeatedly recycled into younger fan sediments during range growth. These ranges grow in width, as well as length and height, at the expense of the intervening basins, which become progressively narrower. The colluvial placers are ultimately reworked into a fluvial placer in an axial river between two ranges, which concentrates all of the colluvial gold into an incised channel once the widening ranges meet. Aeolian placers have formed from fluvial precursors in the semi-arid parts of the rain shadow east of the Southern Alps, particularly on the lower slope of ranges exposed to westerly winds. Silcrete and less common greywacke ventifacts are commonly associated with these placers.
Progressive changes in gold particle shape by flattening during transport in fluvial systems has been the most important process in the concentration of gold in placers. Flattening changes the hydrodynamic behaviour of gold particles by increasing their surface area to volume ratio, thereby making them easier to entrain and enabling transport to lower energy parts of the fluvial system. Gold particle flatness determines whether transport or concentration occurs and there is a predictable relationship between particle flatness and transport distance. This relationship explains the typical occurrence of placers immediately downstream of terminal moraines, the confluence with steeper tributary streams and the mouth of incised gorges. In each case, gold with sub-critical flatness is deposited from a higher energy system or reach into a lower energy system or reach, and must be flattened to a critical state before further transport can occur.
Chemical mobility of gold in groundwater occurs during uplift, commonly in association with sedimentary recycling. Secondary gold overgrowths are common in some placers and stitch or overgrow transport-induced features such as folds and abrasion marks. Chemical mobilisation and re-precipitation of gold is of minor importance, however, and results in volumetrically insignificant amounts of secondary gold. Increases in gold grain size upward through the section on both the local and the regional scale does not result from gold 'growth', but instead from preservation of progressively more proximal reaches of the host placers with decreasing age.
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Neaville, Chris C. "Hydrogeology and simulation of ground-water and surface-water flow in Pinal Creek Basin, Gila County, Arizona." Thesis, The University of Arizona, 1991. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1991_400_sip1_w.pdf&type=application/pdf.
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Roseff, Rebecca. "A study of alluviation in the River Lugg catchment, Herefordshire." Thesis, University of Birmingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343888.
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Gouw, Marc. "Alluvial architecture of the Holocene Rhine-Meuse delta (the Netherlands) and the Lower Mississippi Valley (U.S.A.) /." Utrecht : Koninklijk Nederlands Aardrijkskundig Genootschap, Faculteit Geowetenschappen Universiteit Utrecht, 2007. http://www.loc.gov/catdir/toc/fy0803/2008400359.html.
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Cosio, Sergio Javier 1958. "Infiltration into stratified alluvium : a comparison between simulated values and field measurements." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/191968.
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The computer model UNSAT2 for unsaturated water flow is used to complement a field study conducted at the University of Arizona Water Resources Research Center Field Laboratory during influent seepage along the Santa Cruz River during the runoff events on the Winter of 1967-1968. Field measurements accomplished by a neutron moisture logger showed that the hydrogeologic characteristics governing the movement and storage of subsurface flow are somewhat uniform throughout the area. The mathematical model provides a two-dimensional transient saturated-unsaturated analysis of the subsurface flow at the field site. The results attained using a conceptualized flow region proved to be an acceptable aid to a unified interpretation of the field measurements. Because boundary conditions are time and space dependent, the sensitivity to boundary conditions prevented the successful model calibration, although not its applicability. This, together with more serious limitations on data availability and computer capacity, precluded the imminent use of the computer model UNSAT2 for this individual research site.
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Jones, Heather L. "Characterizing ancient avulsion stratigraphy and its significance." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1338875291&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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D'Urso, Gary John. "Revised glacial margins and Wisconsin meltwater paleoflood hydrology in Slippery Rock Creek Basin, central western Pennsylvania." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1436.
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Thesis (Ph. D.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains x, 174 p. : ill. (some col.), maps (some col.) Includes abstract. Includes bibliographical references (p. 171-174).
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Zhang, Guoping 1968. "Laboratory characterization of a highly weathered old alluvium in San Juan, Puerto Rico." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8295.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.Includes bibliographical references.
The old alluvium underlying much of metropolitan San Juan was formed in early Pleistocene and has undergone substantial post-depositional weathering in the tropical climate of Puerto Rico, resulting in a special combination of soil mineralogy and structure, with very unusual engineering properties. The soil mineralogy was determined both qualitatively and quantitatively by a series of analytical techniques, consisting of X-ray diffraction, thermal analysis, X-ray fluorescence, and chemical analyses including cation exchange capacity (CEC), soil pH, and selective chemical dissolutions (SCD). Results show that the old alluvium contains: (1) two most weathering resistant primary minerals: quartz and orthoclase; (2) kaolinite and smectites as major clay minerals; and (3) Fe-oxides (goethite and hematite) as special fine-grained minerals, which give the soil distinct red, brown, and yellow coloration. The subsequent quantitative analysis yields high accuracy results, such that the identified mineral phases account for 94-95% of the bulk material. Characterization of soil microstructure also used a variety of techniques including environmental scanning electron microscope (ESEM), slaking tests, CEC, and SCD of Fe-oxides. The results reveal an aggregate structure comprising groups of clay platelets, which each consist of clay particles associated with face-to-face contact. Cementation and aggregation agents are positively identified by SCD as Fe-oxides, which form coatings over clay platelets and aggregates, and bridge bonding between aggregates. These results were confirmed by slake tests in water and glycerol.
(cont.) Index properties vary due to the microstructure. Particle size distribution and Atterberg limits are affected by remolding energy and drying conditions, resulting in difficulties for soil classification. The combination of mineralogy and structure, cause the consolidation behavior to differ from conventional sedimentary soil behavior in the following aspects: (1) the coefficient of consolidation decreases by four orders of magnitude as the sample is compressed to 300ksc; (2) the swelling strains increase significantly with maximum past consolidation pressure; (3) the intact soil exhibits an exceptionally high yield stress ([sigma][subscript]y [approximately equal to] 8ksc); and (4) vertical consolidation strains can be completely recovered upon unloading when samples are pre-loaded above the yield stress. Triaxial compression and extension shear tests on intact samples suggest that the intact shear strength can be described by a conventional Mohr-Coulomb criterion with an isotropic cohesive strength component. The current conceptual models of microstructure offer a framework for developing realistic constitutive models to describe the complex mechanical behavior of this complex residual soil.
by Guoping Zhang.
Ph.D.
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Davies, Paul. "Sub-fossil mollusca from Holocene overbank alluvium and other wet-ground contexts in Wessex." Thesis, Cardiff University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281700.
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Fairbairn, Andrew Stephen. "Plant macrofossil analysis of Holocene alluvium, with special reference to the Lower Thames Basin." Thesis, University College London (University of London), 2001. http://discovery.ucl.ac.uk/1317705/.
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Alluvium is an important archaeological and palaeoenvironmental resource in lowland Britain. The research presented here develops plant macrofossil analysis of alluvial facies, with special emphasis on the depositional and natural environments of the Lower Thames Basin. Plant macrofossil analysis is a poorly developed area of alluvial research, usually limited to superficial description of the fossils seen in section, or detailed analysis of a narrow suite of remains. A comprehensive, quantitative method of macrofossil analysis using counts and cover abundance scores is developed. Identification criteria for several groups of macrofossils are presented, including leaves, rootlets and epidermis. Potential macrofossil incorporation was investigated at eight wetland and alluvial sites, including saltmarsh, wet woodland and herb fen environments. Macrofossil collections were compared to extant vegetation and subject to multivariate analysis. The results showed that macrofossil assemblages produce spatially and temporally precise data of plant presences, although spatial and temporal fidelity varies in different depositional environments and between plant taxa. Vegetation dominants were favoured in the assemblages of all classes of macrofossils, with bulky Monocotyledons and Therophytes favourably preserved and sparsely distributed taxa, such as rosette plants, less well favoured. The depositional environment and position in relation to environmental gradients were also found to affect macrofossil composition. Multiple approaches to macrofossil analysis using a wide range of macrofossils were found to produce improved interpretations. The value of different macrofossil classes and occurrences of the major observed taxa in alluvial sediments are discussed. The method was applied to samples from the Medway River at Chatham. Vegetation history, hydrology and traces of human disturbance are discussed from 7000BP to 2000BP. Analysis showed a gradual increase in human disturbance over time, development of a distinctive human-influenced upper salt marsh flora from 3000BP and supports the trend across southern Britain for a change in hydrology by the same period.
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McMahon, William. "Pre-vegetation alluvium : geological evidence for river behaviour in the absence of land plants." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/276277.
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Pre-vegetation alluvium is unique; at the present day, plants affect multiple aspects of river functioning and deposition and so those rivers that operated before the evolution of land plants largely lack modern sedimentological analogue. However, such rivers were the norm for the first 90% of Earth history and so a better understanding of their sedimentary product enables insight into both the fundamental underlying mechanisms of river behaviour and the ways in which fluvial processes operated on ancient Earth and other rocky planets. This study presents five original fieldwork based case studies and an analysis of a holistic database of all of Earth’s pre-vegetation alluvium. Together these research strands offer perspectives on the sedimentological characteristics and stratigraphic trends of pre-vegetation alluvium and the behaviour and functioning of pre-vegetation rivers. Results show that, in pre-vegetation alluvial settings: 1) a variety of fluvial styles are represented, but diminished in comparison with syn-vegetation alluvium; 2) ‘sheet-braided’ architectures are common but may record a variety of fluvial planforms; 3) meandering planforms were less frequent, particularly in small- to moderate-sized river systems; 4) mudrock is on average 1.4 orders of magnitude less common than it is in syn-vegetation alluvium; and 5) microbial matgrounds were present, but had negligible effect on preserved architecture and facies. This thesis demonstrates that whilst the physical laws governing fluvial fluid-sediment interaction have not changed, the theatre in which they operated irrevocably evolved with the greening of the continents.
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Santucci, Jay N. "Hydrogeologic conditions controlling contaminant migration from storage tanks overlying Mississippi River Alluvium a case study /." Master's thesis, Mississippi State : Mississippi State University, 2006. http://library.msstate.edu/etd/show.asp?etd=etd-07072006-161425.
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Ng, Chi Hong. "Comparative study of soil constitutive models on simulation of a diaphragm walled excavation in Macao alluvium." Thesis, University of Macau, 2009. http://umaclib3.umac.mo/record=b2099643.
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Vanbuskirk, Stephanie. "Alluvial stratigraphy and soil formation at Cox Ranch Pueblo, New Mexico." Online access for everyone, 2004. http://www.dissertations.wsu.edu/Thesis/Fall2004/s%5Fvanbuskirk%5F120904.pdf.
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McHarge, Jennifer L. "Evaluating controls on fluvial architecture, Lance Formation, Bighorn Basin, Wyoming." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1683456271&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Pickles, A. R. "The application of critical state soil mechanics to predict ground deformations below an embankment constructed on soft alluvium." Thesis, City University London, 1989. http://openaccess.city.ac.uk/7404/.
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An embankment has been constructed to a maximum height of approximately twelve metres at Beckton, east London. The embankment is underlain by up to eight metres of alluvium and made ground. The embankment was monitored during construction. Centreline settlements of the order of O.6m and horizontal movements at the embankment toe of up to O.1Sm were measured. The excess pore pressures generated during construction were found to dissipate rapidly. Soil samples recovered from the site have been tested at city University. The alluvial clay is shown to have extremely variable compression characteristics and it is not possible to determine a single set of critical state soil parameters from the "undisturbed" soil samples. The use in design of parameters derived from reconstituted soil samples is investigated. Laboratory test results indicate that a small quantity'of organic matter in the soil has a large effect on the engineering properties of the alluvial clay. The importance of not dry~ng soils which contain organic matter is highlighted. It is shown that, despite the effects of the organic matter, critical state concepts and in particular the modified Cam clay soil model can be used to predict the behaviour of the alluvial clay in a wide variety of laboratory tests. standard methods of determining the yield stress or preconsolidation pressure are shown to be inadequate when used to analyse the results of compression tests performed at a constant rate of loading. An alternative method, the Lambda construction, is proposed and this is shown to be both reliable and objective. Two distinct testing methods have been used to probe the state boundary surface of the reconstituted alluvial clay samples. The results of these tests appear to indicate the existence of a single state boundary surface for both Ko and isotropically compressed samples. This surface has a shape similar to that predicted by the modified Cam clay soil model. This result conflicts with the findings of many other investigators. Finite element modelling of the embankment construction has been carried out. A single set of soil parameters derived from tests on the reconstituted clay were used to represent the alluvial stratum. The construction of the embankment was modelled as a drained event. The results are shown to compare favourably with the actual field data.
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Rutland, Jeffrey R. "Depositional environments comprising the Birch River section (Middle Pennsylvanian), Powell Mountain, Nicholas County, West Virginia." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3461.
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Thesis (M.S.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains vii, 198 p. : ill. (some col.), maps. Includes abstract. Includes bibliographical references (p. 161-167).
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Mubamu, Makady Elvis. "Large herbivore stocking rate effects on plant palatability, forage preference and soil properties in an Alluvium Fynbos-Renosterveld mosaic." Thesis, Stellenbosch : Stellenbosch University, 2009. http://hdl.handle.net/10019.1/4043.
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Thesis (MSc (Conservation Ecology and Entomology))--Stellenbosch University, 2009.ENGLISH ABSTRACT: An understanding of the interactions of herbivores, plant nutrients and soil properties is crucial for grazing management. Of particular interest are plant palatability and herbivore grazing preferences. These aspects, the focus of this thesis, were studied in a Swartland Shale Renosterveld and Swartland Alluvium Fynbos mosaic in the Western Cape of South Africa. This vegetation is classified as critically endangered due to the transformation of its landscape in favour of agricultural production and urban settlement. Pre-colonial herbivore vertebrates were hunted out by 1700, leading to a sparse knowledge of the early dynamics of the vegetation. However, currently game farmers and landowners are re-introducing selected species into the area. Thus, managers require knowledge on how to implement practical guidelines for best-practice grazing management. This study investigates, firstly, the relationship between plants and animals. This included seasonal assessment of seed germination from dung of bontebok and eland; the effect of stocking rates on plant palatability (crude protein, crude fibre, crude fat, moisture, tannin and mineral) of herbage was studied with the aim to understand how palatability influences herbivore forage decisions. Secondly, this study looked at how stocking rates influence soil nutrients (nitrogen, phosphorus), and others soil properties such as pH and soil moisture. The distribution of alien grasses was facilitated by grazers. About 58 % of grasses germinated from the dung of eland and Bontebok were alien species. Additionally, there was significant variation in palatability related to grazing pressure and plant maturity between sites and over seasons. Grasses on the high grazing site had higher carbohydrate (3%-5% higher) and protein content (1%-5% higher) than at the least grazed site. Mature grasses contained less water (10%-20%), but no obvious variation in tannin concentration than immature grasses. However, species such as Ficinia sp. showed variations with grazing pressure and maturity. Ficinia sp. on the high grazing site had higher tannin concentration (5mg/ml-22mg/ml) and crude protein (4%-9%) than at the least grazed site. When the plant ages, tannin concentration increase (ranging from 15% to19% higher). Two types of plant were recoreded according to their chemical response following grazing pressure. These types are 1) plants that are grazing tolerant and which produce more carbohydrate when grazed and 2) plants that are grazing intolerant under high grazing pressure and which produce chemical defence compounds such as tannin to deter herbivores attacks. The results indicate that in fynbos and renosterveld, the relationship between preference and plant chemical compounds is not consistent since no IV patterns emerged to explain what compounds drive preference. A combination of chemical compounds may be the reason for the selection by the grazers; alternatively, other compounds not included in the study may influence the forage selection by an herbivore. The second part of the study showed that stocking rates appeared to have a significant effect on soil properties investigated. Soil moisture was significantly affected by the stocking rate in autumn. The high grazing intensity site had the lowest soil moisture especially in autumn (10% lower than the control site), likely due to heavy trampling and soil compaction. pH was the lowest at the high grazing intensity site in all seasons compared to the control site. Likely reasons were the high deposition of nitrogen through dung and urine deposition, high removal of basic cations and animal exportation through hunting activities. Lastly, grazing maintains inorganic nitrogen at stable levels regardless of seasonal changes and increases the concentration of phosphorus especially under high grazing pressure compare to less grazed sites. The grazing dynamics of Swartland Shale Renosterveld - Swartland Alluvium Fynbos mosaic system are complex and multifaceted. Farmers need to pay attention to the nutritional status of plant species grazed to know whether they meet the nutritional requirements of the game in the area. Overstocking should be avoided in this system as it triggers the production of tanniferous compounds that could decrease the survivorship of herbivores. Moderate grazing 0.09 LAU/ha pressure provides the best stocking rates for effective grazing management.
AFRIKAANSE OPSOMMING: Vir suksesvolle weidingsbestuur is dit noodsaaklik om die interaksie tussen herbivore, plantvoedingstowwe en grondeienskappe te verstaan. Van besondere belang is plantsmaaklikheid en herbivore se weidingsvoorkeure. Hierdie aspekte, wat die fokus van hierdie tesis is, is bestudeer in ‘n Swartland Shale Renosterveld en Swartland Alluvium Fynbos-mosaïek in die Wes-Kaap Provinsie van Suid-Afrika. Hierdie plantegroei word as kritiek bedreigd geklassifiseer weens die transformering van sy landskap ten gunste van landbou-aktiwiteite en stedelike vestiging. Pre-koloniale herbivoor vertebrata is teen 1700 deur jagters uitgeroei, wat gelei het tot min kennis oor die vroeë dinamiek van die plantegroei. Wildsboere en grondeienaars is egter besig om geselekteerde spesies in die area te hervestig. Bestuurders moet dus weet hoe om praktiese riglyne vir beste-praktyk weidingsbestuur te implementeer. Hierdie studie ondersoek eerstens die verhouding tussen plante en diere. Dit sluit seisoenale evaluering van saadontkieming uit die mis van bontebokke en elande in; die effek van veegetalle op plantsmaaklikheid (ruproteïen, ruvesel, ru-vet, vogpeil, tannien en minerale) van die weiveld is bestudeer om vas te stel hoe plantsmaaklikheid herbivore se weidingsbesluite beïnvloed. Tweedens het die studie die invloed van veegetalle op grondvoedingstowwe (stikstof, fosfor) ondersoek, asook ander grondeienskappe soos pH en grondvogpeile. Die verspreiding van uitheemse grasse is deur weidende diere gefassiliteer. Ongeveer 58% van alle grasse wat uit die mis van elande en bontebokke ontkiem het, was uitheemse spesies. Verder was daar beduidende variasie in plantsmaaklikheid verwant aan beweidingsdruk en plantvolwassenheid tussen verskillende persele en oor seisoene. Grasse op die hoogs beweide persele het 3%-5% hoër koolhidraatinhoude en 1%-5% hoër proteïeninhoude gehad as die minder beweide persele. Volwasse grasse het 10%-20% minder water bevat as onvolwasse grasse, maar het nie in terme van tannienkonsentrasie van die onvolwasse grasse verskil nie. Spesies soos Ficinia sp. het variasies getoon met beweidingsdruk en volwassenheid. Ficinia sp. het op die hoog-beweide perseel ‘n hoër tannienkonsentrasie (5mg/ml-22mg/ml) en meer ruproteïen (4%-9%) gehad as op die minste beweide perseel. Wanneer die plant verouder, verhoog die toename in tannienkonsentrasie (met tussen 15% en 19%). Twee tipes plante is aangeteken volgens hul chemiese response ná beweidingsdruk. Hierdie tipes is 1) plante wat beweidingstolerant is en wat meer koolhidrate produseer wanneer hulle as weiding dien en 2) plante wat onder hoë beweidingsdruk beweidingsintolerant is en wat chemiese verbindings VI soos tannien produseer om herbivooraanvalle af te weer. Die resultate dui aan dat die verhouding tussen voorkeur en plante se chemiese verbindings nie konstant bly in fynbos en renosterveld nie, aangesien geen patrone na vore getree het wat kon verklaar watter verbindings bepalend is vir voorkeur nie. ‘n Kombinasie van chemiese verbindings mag die rede wees waarom die herbivore sekere plante verkies; alternatiewelik mag ‘n herbivoor se plantseleksie beïnvloed word deur chemiese verbindings anders as dié wat in hierdie studie ondersoek is. Die tweede deel van die studie het aangetoon dat veegetalle blyk ‘n beduidende invloed te hê op die grondeienskappe wat ondersoek is. Grondvogpeile is in die herfs beduidend beïnvloed deur die veegetalle. Die perseel met die hoë beweidingsintensiteit het die laagste grondvogpeil gehad, veral in die winter (10% laer as dié van die kontrole-perseel), waarskynlik weens erge getrappel en grondkompaktering. Vergeleke met die kontrole-perseel was pH die laagste op die perseel met die hoë beweidingsintensiteit, in alle seisoene. Waarskynlike redes hiervoor is die hoë neeerslag van stikstof deur mis- en uriene-neerslae, hoë verwydering van basiese katione en dierevervoer wat deur jagaktiwiteite teweeg gebring word. Laatstens behou weiding anorganiese stikstof teen stabiele vlakke ongeag van seisoenale veranderinge en toenames in die konsentrasie van fosfor, veral onder hoë beweidingsdruk vergeleke met minder beweide persele. Die weidingsdinamiek van die Swartland Shale Renosterveld - Swartland Alluvium Fynbosmosaïeksisteem is kompleks en veelvlakkig. Boere behoort aandag te skenk aan die voedingstofstatus van die plantspesies wat as weiding dien, sodat hulle kan weet of die voedingsbehoeftes van die wild in die omgewing bevredig word. Die aanhou van te veel vee in hierdie sisteem behoort vermy te word aangesien dit as sneller dien vir die produksie van tannienbevattende verbindings wat die oorlewingsvermoë van herbivore kan verlaag. Matige beweidingsdruk (0.09 LAU/ha) bied vir effektiewe weidingsbestuur die beste veegetalle.
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Tainer, Erin Margaret. "High-Resolution Holocene Alluvial Chronostratigraphy at Archaeological Sites in Eastern Grand Canyon, Arizona." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/551.
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Understanding the nature of Colorado River deposits in Grand Canyon helps reveal how the river responds to changes in its Colorado Plateau tributaries and Rocky Mountain headwaters. This study focused on Holocene alluvial deposits associated with archaeological sites excavated near Ninemile Draw in Glen Canyon and at Tanner Bar in eastern Grand Canyon. Two previously-developed conceptual models of deposition were tested based on previous work. Previous researchers have suggested that Holocene alluvial deposits in Grand Canyon are a series of inset aggradational packages that correlate to valley fills and arroyo-cutting cycles in Colorado Plateau tributaries and are laterally consistent throughout the river corridor. An alternate hypothesis is that alluvial packages record paleoflood sequences along the Colorado River with no Holocene change in river grade. In this model, deposits are preserved more variably as a function of local hydrologic geometry, and they should be less correlatable. Detailed stratigraphic columns of terrace deposits and several stratigraphic panels of archaeological trenches, combined with facies interpretations, were used to reconstruct a high-resolution alluvial history at two locations. Optically stimulated luminescence (OSL) and radiocarbon dating methods were used at both locations with consistent results. At both sites, the sediment includes multiple depositional facies of mainstem and local-source material, and it consists of stratal packages bound by unconformities. These stratigraphic relations, combined with geochronology, lead to the interpretation that the alluvium is composed of six correlatable alluvial packages at overlapping heights above river level throughout the canyon. The four older packages include facies that imply aggradation throughout the river corridor, suggesting oscillations in river grade. The youngest two packages consist only of mainstem flood deposits. These packages suggest that preservation of deposits over the past ~1 ky has not been driven by aggradation, although incision since ~1 ky is possible. Comparison of the interpreted chronostratigraphy to climate records suggests that this large river's grade has not responded visibly to smaller century to millennial-scale climate oscillations. This work is the first to document that the alluvial record in Grand Canyon spans the entire Holocene, and conclusions support to both previous conceptual models of deposition.
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Sciscio, Lara. "Neogene fluvial deposits along the south-west coast of South Africa understanding the palaeoclimate through proxies." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1005593.
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Branched glycerol dialkyl glycerol tetraether (GDGTs) membrane lipids have been used as a new proxy for the reconstruction of terrestrial palaeoclimates. These biomarkers (or molecular ‗fossils‘) in conjunction with palynology, have been effective in the novel analysis of Miocene organic-rich sediments from three South African west coast sites at Rondeberg, Noordhoek and Langebaanweg. Lastly, a Quaternary south coast site at Rietvlei, South Africa, was also studied to further elucidate the extent of use of this new proxy. The fluvial peat and organic-rich deposits of the Elandsfontyn Formation (Sandveld Group) were investigated at Noordhoek, Langebaanweg and Rondeberg to provide new evidence for the climate and vegetation patterns during Miocene in this region. Drill-core and quarry samples from all four sites were freeze-dried, powered, and prepared for biogeochemical and palynological analyses. The methylation index of branched tetraethers (MBT) and cyclisation ratio of branched tetraethers (CBT) proxies were used to calculate the mean annual air temperature (MAAT) and pH values of the organic-rich horizons at time of deposition. The Branched versus isoprenoid index of tetraethers (BIT) was used to assess the relative contributions of marine archaeal and terrestrial bacterial tetraethers, and thereby assess the validity of the MBT, CBT and calculated palaeoenvironmental factors. The results presented in this thesis suggest that the use of the MBT/CBT proxy has significant potential in southern Africa, and may complement previously attempted palaeoclimatic and palaeoecological studies of Neogene-aged South African sediments. This type of research has the capacity to provide palaeoenvironmental information where other proxies may be absent. Results indicate that all sites yielded branched tetraether membrane lipids with the exception of Rondeberg, where GDGTs were below detection as a result of poor preservation conditions. Palynological investigation confirmed proxy derived temperatures. Furthermore palynomorph analyses supplemented earlier studies of the Noordhoek site and were piloted for the Rondeberg site, reaffirming alternating sequences of tropical and subtropical palynofloras. The MAATs, likewise, show variability and pronounced trends through time at the Langebaanweg and Noordhoek sites, generally corresponding with the variation and diversity of the pollen population. The terrestrial MAAT results appear to compliment Southern Hemisphere sea level changes associated with Antarctic glaciations. Additionally, this data shows a pattern similar to the Southern and Northern Hemisphere marine isotope records of relative fluctuations in the global climate and sea level change from the early to middle Miocene. The application of these past climate change indicators have been proved to be useful in the reconstruction of South Africa Miocene palaeoclimates, and may aid in understanding the consequences of climate change in the Cape region.
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Gondi-M'Bouala, Paule Christiane. "Étude des minéraux lourds des alluvions de la zone diamantifère de Makongonio - Gabon : application à la recherche des kimberlites ou des lamproites." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL134N.
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Le but de cette étude est de rechercher la source primaire du diamant des alluvions de la zone de Makongonio, Gabon, en étudiant les minéraux lourds de celles-ci. Elle comprend donc une introduction aux gisements primaires et secondaires de diamant. Puis une première partie consacrée aux généralités sur les kimberlites et les lamproites, sources primaires terrestres de diamant naturel connues. Enfin une deuxième partie qui traite de l'étude des échantillons des minéraux lourds provenant de Makongonio, des méthodes analytiques utilisées et des résultats obtenus. Cette étude révèle la présence des minéraux satellites tels que l'ilménite magnésienne, les spinelles chromifères, les zircons, l'olivine et la chlorite. Un cortège minéralogique qu'on trouve dans les kimberlites ou les lamproites, roches d'où pourrait provenir ce diamant
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Pereira, Gabriel da Silva. "Senhora de bens: famílias, negócios e patrimônios administrados por mulheres no sertão dos Guayazes – 1760- 1840." Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/4680.
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The thesis that’s presented aims to revive women's groups seeking prestige, enrichment and power in Goiás, along the eighteenth century. We look at the sources the circumstances indicating the possibility of some form of consensual relationship to achieve the stories of their members, not only the relations in which concubinage actually happened. With this criterion, our eyes were directed to cases of widowhood, failure of marriage and singleness. This allowed us a more critical approach about what is reported by the women in the sources, because provided us relativize the importance of marriage in this society, and also highlight the scenarios of autonomy, construction and affirmation of their identities and powers and also their strategies sociability. Situations of "possible families" allowed to discover a group of power, with the presence of autonomous and capable women, who wished for social distinction, honor preservation, enrichment and increase their wealth, characterizing an peculiar nobility from Goiás, the alluvium nobility, which means a apparent wealth, surface such as gravel, sand, silt, and organic and inorganic materials left by the waters. In Goiás, during the eighteenth century, to enter into this category of nobility constituted in desire of men and women who, through their occupations and social relationships, accumulating richness, expanding their wealth and uppers, differing from most of his countrymen, because of the acquisition of honorifics or social power and influence that comes from the enrichment. This means that the in the mines from Goiás, we see the trajectory of several people who lived in this search, the desire to enrich themselves in a context of conquest, characterized by hostile realities, often marked by power struggles and violence.
A dissertação que ora é apresentada objetiva resgatar os grupos femininos que buscavam o prestígio, o enriquecimento e o poder em Goiás, ao longo do setecentos. Para alcançarmos as histórias de suas integrantes, procuramos nas fontes as circunstâncias que indicassem a possibilidade de algum tipo de relação consensual – como o concubinato – e não apenas os casos em que ela, de fato, ocorreu. Com base nesse critério, nosso olhar foi direcionado às situações de viuvez, de fracasso do matrimônio e de solteirice. Isso nos permitiu uma abordagem mais ampla e crítica ao que é relatado pelas próprias mulheres nas fontes, uma vez que nos proporcionou relativizar a importância do matrimônio nessa sociedade, bem como, destacar os cenários de autonomia, de construção e afirmação de suas identidades e poderes, além de suas estratégias de sociabilidades. As situações de famílias possíveis oportunizaram-nos descobrir um grupo de poder, composto por mulheres autônomas e capazes, que ansiavam por distinção social, preservação da honra, enriquecimento e aumento de seus patrimônios, caracterizando uma nobreza peculiar da região de Goiás, a nobreza de aluvião, ou seja, uma riqueza aparente, de superfície como o cascalho, areia, lodo e matérias orgânicas e inorgânicas deixado pelas águas. Em Goiás, durante o século XVIII, inserir-se nesta categoria de nobreza constituía-se em desejo de homens e mulheres que, por meio de seus ofícios e relações sociais, acumulavam riquezas, ampliando, assim, seus patrimônios e cabedais, diferenciando-se da maior parte de seus conterrâneos, devido à aquisição de títulos honoríficos ou, simplesmente, ao poder social e de influência que advém do enriquecimento. Neste sentido, as tramas da sociedade mineradora goiana denotam a trajetória de várias personagens que vivenciaram essa busca, essa vontade de se enriquecer – e seu alcance de fato – num contexto de conquista, caracterizado por realidades adversas e, muitas vezes, marcado pelos conflitos de poder e violência.
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Dvoracek, Pavel. "Hydrogeological framework, conceptual and numerical groundwater flow model of Laidley Creek catchment, Queensland, Australia." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/61559/2/Pavel_Dvoracek_Thesis.pdf.
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This thesis studies the water resources of Laidley Creek catchment within the Lockyer Valley where groundwater is used for intensive irrigation of crops. A holistic approach was used to consider groundwater within the total water cycle. The project mapped the geology, measured stream flows and groundwater levels, and analysed the chemistry of the waters. These data were integrated within a catchment-wide conceptual model, including historic and rainfall records. From this a numerical simulation was produced to test data validity and develop predictions of behaviour, which can support management decisions, particularly in times of variable climate.
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Caldwell, Rodney R. "Geochemistry, Alluvial Facies Distribution, Hydrogeology, and Groundwater Quality of the Dallas-Monmouth Area, Oregon." PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/4573.
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The Dallas-Monmouth area, located in the west-central Willamette Valley, Oregon, consists of Tertiary marine and volcanic bedrock units which are locally overlain by alluvium. The occurrence of groundwater with high salinities has forced many rural residents to use public water supplies. Lithologic descriptions from driller's logs, geochemical (INAA), and x-ray diffraction analyses were used to determine alluvial facies distribution, geochemical and clay mineral distinctions among the units, and possible sediment sources. Driller's log, chemical and isotopic analysis, and specific conductance information from wells and springs were used to study the hydrogeologic characteristics of the aquifers and determine the distribution, characteristics, controlling factors, and origin of the problem groundwaters. Three lithologic units are recognized within the alluvium on the basis of grain-size: 1) a lower fine-grained unit; 2) a coarse-grained unit; and 3) an upper fine-grained unit. As indicated by geochemical data, probable sediment sources include: 1) Cascade Range for the recent river alluvium; 2) Columbia Basin plutonic or metamorphic rocks for the upper fine-grained older alluvium; and 3) Siletz River Volcanics from the west for the coarse-grained sediment of the older alluvium. The Spencer Formation (Ts) is geochemically distinct from the Yamhill Formation (Ty) and the undifferentiated Eocene-Oligocene sedimentary rock (Toe) with higher Th, Rb, K, and La and lower Fe, Sc, and Co concentrations. The clay mineralogy of the Ty is predominantly smectite (86%) while the Ts contains a more varied clay suite (kaolinite, 39%; smectite, 53%; and illite 8%). The Ty and Toe are geochemically similar, but are separated stratigraphically by the Ts. The Siletz River Volcanics is distinct from the marine sedimentary units with higher Fe, Na, Co, Cr and Sc concentrations. The Ty and Toe are geochemically similar to volcanic-arc derived sediments while the Ts is similar to more chemically-evolved continental crust material. Wells that encounter groundwater with high salinities (TDS>300 mg/1): 1) obtain water from the marine sedimentary bedrock units or the older alluvium; 2) are completed within zones of relatively low permeability (specific capacities ~5 gpm/ft); and 3) are located in relatively low-lying topographic settings. The poor quality waters occurring under these conditions may be due to the occurrence of mineralized, regional flow system waters. Aquifers of low permeability are less likely to be flushed with recent meteoric water, whereas upland areas and areas with little low permeability overburden are likely zones of active recharge and flushing with fresh, meteoric water. The most saline waters sampled have average isotopic values (6D = -6.7 ° / 00 and 60 = -1.7 ° / 00 ) very near to SMOW, while the other waters sampled have isotopic signatures indicative of a local meteoric origin. The Br/Cl ratios of most (10 of 14) of the waters sampled are within 20% of seawater. A marine connate origin is proposed for these waters with varying amounts of dilution with meteoric waters and water-rock interaction. The problem waters can be classified into three chemically distinct groups: 1) CaC12 waters, with Ca as the dominant cation; 2) NaCl waters with Na as the dominant cation; and 3) Na-Ca-Cl waters with nearly equal Na and Ca concentrations. The NaCl and CaC12 waters may have similar marine connate origins, but have undergone different evolutionary histories. The Na-Ca-Cl waters may represent a mixing of the NaCl and CaC12 waters.
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Watha-Ndoudy, Noël. "Caractéristiques morphologiques et géochimiques des grains d'or : application a la prospection des placers de Mayoko (Congo)." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL113N.
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Les connaissances ponctuelles acquises ces dernières années sur les caractéristiques morphologiques et géochimiques des grains d'or suggèrent que celles-ci sont tributaires de l'histoire géologique de cet or (formation, transport, évolution post-sédimentaire). Dans le cadre de la prospection des placers, il est d'usage d'échantillonner les alluvions d'aval en amont pour rechercher les sources des apports en minerais et localiser approximativement les gites primaires. Il apparait donc théoriquement possible d'appuyer des prospections d'or, en utilisant les caractéristiques des grains trouvés dans les placers pour déterminer leur distance de transport. Dans l'objectif de vérifier dans quelles conditions ces paramètres peuvent aider à mieux orienter des campagnes de prospection, quelques échantillons de grains d'or provenant de différents milieux alluviaux et éluviaux ont été étudiés. Il en ressort que les caractéristiques des grains d'or peuvent être regroupées en deux catégories: celle qui indique l'importance du transport subi par les grains (données morphologiques); celle qui renseigne sur le milieu de genèse des grains (composition chimique et nature des inclusions minérales). Dans le cas ou l'on connait déjà des minéralisations primaires, l'utilisation judicieuse des caractéristiques précitées peut permettre de mettre en évidence de nouvelles sources de l'or des placers. Dans le cas ou les sources de l'or sont encore inconnues, en utilisant le schéma graduel indiqué, on peut dans un grand nombre de cas, situer avec assez de précision la zone source de l'or étudié. En même temps il est possible de prévoir son mode de gisement et d'obtenir quelques éléments sur sa metallogenèse. Ce schéma applique aux alluvions de Mayoko (Congo) montre que l'or de cette zone n'a subi qu'un transport peu important. Sa source est donc à rechercher au sein même de l'enclave métamorphique. Les données metallogéniques du secteur soutiennent cette approche. Enfin, une typologie indicative des minéralisations qui ont pu alimenter en or ces alluvions est présentée
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Tevissen, Etienne. "Méthodologie d'étude et modélisation du transport de solutes en milieux poreux naturels : application à la migration du chrome dans la nappe alluviale du Drac (Isère)." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL089N.
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On présente une méthodologie d'étude du transport de solutés interactifs en milieu poreux naturel, basée sur l'expérimentation et la modélisation. La modélisation s'effectue grâce à un code de calcul couplant hydrodynamique et géochimie, des améliorations y sont apportées avec la prise en compte de corrections d'activité et surtout, avec la simulation d'effets cinétiques chimiques ou diffusionnels. La méthodologie proposée a été appliquée au cas de migration du chrome dans la nappe alluviale du Drac (Isère). L'étude du site expérimental associée à la connaissance générale de la chimie du chrome, a permis de définir et de cadrer les expériences à mener au laboratoire pour caractériser les interactions du chrome avec les alluvions. Ces expériences ont montré que c'est un phénomène d'adsorption qui impose la répartition du chrome hexavalent entre phases mobile et immobile. Ce phénomène a ensuite été décrit à l'équilibre thermodynamique par deux modèles, le premier utilise un phénomène élémentaire de type échange anionique entre chromate et bicarbonate, le second est résumé à une loi de Langmuir. Les courbes expérimentales ont été simulées en considérant ces deux modèles avec des limitations cinétiques. Les expériences de traçage sur le site ont montre que le chrome hexavalent y a un comportement equivalent a un traceur d'eau. Ce résultat souligne que certains paramètres capacitifs des interactions ne peuvent être déterminés au laboratoire et doivent faire l'objet de mesures in-situ
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Moura, Idembergue Barroso Macedo de. "Estudos das Ãguas da bacia hidrogrÃfica do rio Banabuià no trecho entre Quixeramobim e Banabuià - CearÃ, Brasil." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9971.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoA Ãrea deste estudo de hidrogeologia abrange a Bacia do BanabuiÃ, trecho entre Quixeramobim e BanabuiÃ, e està localizada Ãs margens dos rios Quixeramobim e BanabuiÃ. à necessÃrio para os usuÃrios e gestores conhecer os aspectos qualitativos e quantitativos das Ãguas usadas e a interaÃÃo entre as Ãguas dos rios Quixeramobim e Banabuià com os aquÃferos aluvionares. O objetivo deste estudo foi aprofundar os conhecimentos sobre a hidrogeologia dos aluviÃes em relaÃÃo Ãs reservas, qualidade e hidrodinÃmica das Ãguas. Para isto, realizou-se o cadastro de poÃos, monitoramento das variaÃÃes dos nÃveis estÃticos, levantamento planialtimÃtrico, levantamento geofÃsico por resistividade, medidas de parÃmetros fÃsico-quÃmicos, biolÃgicos, metais pesados, anÃlises isotÃpicas (18O e D) nas Ãguas da chuva, dos poÃos, dos rios Banabuià e Quixeramobim, e do aÃude BanabuiÃ. A estimativa das reservas dos aquÃferos aluvionares tambÃm foi realizada. No tratamento e interpretaÃÃo dos dados usou-se o diagrama de Piper, diagrama USSL, Ato e Resist, para interpretaÃÃo das SEVs, programa Surfer 8.0 para simulaÃÃo do fluxo subterrÃneo, e padrÃes de potabilidade da portaria N 2914/2011 do MinistÃrio da SaÃde. Verificou-se que o fluxo subterrÃneo dirige-se na mesma direÃÃo dos rios Quixeramobim e BanabuiÃ, ou seja, em direÃÃo ao Leste. O aquÃfero aluvionar apresenta uma espessura mÃdia da ordem de 7,08 m. A recarga dos aluviÃes no trecho entre Quixeramobim e Banabuià foi de 6,09x106 m3/ano e a reserva permanente à de aproximadamente 34,8x106 m3. Os principais problemas para o consumo humano das Ãguas (superficiais e subterrÃneas) sÃo os coliformes totais, o elemento ferro, a elevada salinidade, o nitrato, o manganÃs e o alumÃnio, estes se encontram com valores acima do permitido pela Portaria n 2914 do MinistÃrio da SaÃde. Portanto, estas Ãguas sà podem ser consumidas apÃs o devido tratamento. Para o uso na irrigaÃÃo, as Ãguas superficiais e dos aluviÃes podem ser utilizadas sem muitos problemas, jà a Ãgua do domÃnio hidrogeolÃgico cristalino, requer uma prÃtica de irrigaÃÃo controlada. A reta meteÃrica local dos isÃtopos estÃveis para o perÃodo estudado foi muito semelhante à GMWL. Os aquÃferos aluvionares recebem alimentaÃÃo pelos rios Quixeramobim e BanabuiÃ. As Ãguas dos poÃos do domÃnio hidrogeolÃgico cristalino sofreram recarga apenas por Ãguas meteÃricas. As Ãguas dos poÃos do aquÃfero aluvionar sugerem que sofreram evaporaÃÃo durante a recarga. Finalmente, ocorre uma estratificaÃÃo (tÃrmica e quÃmica) no perÃodo chuvoso e uma desestratificaÃÃo no perÃodo de estiagem.
The area of this hydrogeological study covers the Banabuià Basin, in the stretch between Quixeramobim and BanabuiÃ, and is located on the banks of rivers Quixeramobim and BanabuiÃ. It is necessary for users and water managers to be aware of the qualitative and quantitative aspects of the water and the interaction between the rivers Quixeramobim and Banabuià and the alluvial aquifers. For these reasons, we sought to deepen the knowledge about the hydrogeology of the alluvial deposits with respect to reserves, hydrodynamics and water quality. Methods included a data bank of wells, monitoring of changes in static levels, a planialtimetric survey, a geophysical survey by electric resistivity, measurements of physico-chemical and biological parameters, heavy metals, stable isotope analyses (18O and D) in rain, waters from wells, rivers Banabuià and Quixeramobim, and Banabuià dam. An estimation of reserves of alluvial aquifers was also made. In the treatment and interpretation of the data Piper and USSL diagrams were used as well as, Ato and Resist for interpretation of VES, program Surfer 8.0 for simulation of groundwater flow; potability standards of Portaria NÂ. 2914/2011 of the Ministry of Health were used to judge water quality. Results indicate that the groundwater flow has in the same direction of rivers Quixeramobim and BanabuiÃ, ie eastward. The alluvial aquifer has an average thickness of approximately 7.1 m. The recharge to the alluvium in the stretch between Quixeramobim and Banabuià was of 6.09 x106 m3/year and permanent reserve is of approximately 34.8 x106 m3. The main problems for human consumption of the waters (surface and groundwater) are total coliforms, the element iron, high salinity, nitrate, manganese and aluminum; these present values higher than permitted by Portaria N 2914. Therefore, these waters can only be consumed after proper treatment. In irrigation, surface water and alluvium can be used without many problems; however, waters from the crystalline domain require a practice of controlled irrigation. The stable isotope local meteoric water line for the period studied showed a slope very similar to the GMWL. The alluvial aquifers receive recharge from rivers Quixeramobim and BanabuiÃ. Wells in the crystalline bedrock receive recharge by rainwater. The waters of the alluvial aquifer wells suggest that they suffered evaporation while recharging. Finally, there is a slight stratification in Banabuià dam (thermal and chemical) in the rainy season that disappears in the dry season.
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Du, Plessis Paul Jacobus. "An annotated translation of Bartolus' Tractatus de fluminibus seu Tyberiadis (Book 1) / Paul Jacobus du Plessis." Thesis, Potchefstroom University for Christian Higher Education, 1999. http://hdl.handle.net/10394/8600.
Full textAbstract:
South African common law represents a European ius commune based upon Roman law
and Roman-Dutch law of the seventeenth century. Included within South African
common law is a large volume of medieval commentaries on Roman law, rarely touched
upon by legal historians. The number of South African legal practitioners with a working
knowledge of Latin has rapidly declined since the abolition of Latin as a compulsory subject for the LL.B degree in 1996. This state of affairs has led to the marginalisation of
untranslated common law sources, as fewer legal practitioners are able to read and
understand Latin. Although many Roman legal sources have already been translated into
modem Romance languages, medieval commentaries on Roman law are still largely
untranslated and therefore of little value to most legal practitioners. The idiosyncrasies
and peculiar language of medieval legal Latin has further contributed to the
untranslatability thereof, and even jurists with a working knowledge of classical Latin
find it difficult to translate. This study aims to provide access through translation and
historical annotation to an important untranslated medieval legal text, the Tractatus de
jluminibus seu Tyberiadis by the medieval Italian jurist, Bartolus of Saxoferrato (1313 -
1357). The text is concerned with alluvion, an original mode of acquisition of ownership,
which is still relevant in contemporary South African law and has recently been
perpetuated in section 33 of the Land Survey Act 8 of 1997.Thesis (M.A.)--Potchefstroom University for Christian Higher Education, 2000
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Novel, Jean-Paul. "Contribution de la géochimie à l'étude d'un aquifère alluvial de montagne : cas de la vallée d'Aoste-Italie." Paris 6, 1995. http://www.theses.fr/1995PA066419.
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La gestion de la ressource en eau en milieu alluvionnaire de montagne, nécessite une définition à la fois de l'origine et de la dynamique des écoulements souterrains dans ce type d'aquifère. Cette définition implique par conséquent la prise en considération des autres compartiments du système hydrologique du domaine montagnard, c'est-à-dire les précipitations, le réseau de surface et les aquifères de versant. L'étude hydrogéologique de l'aquifère alluvial de la plaine d’Aoste (Italie), pris comme référence pour les alpes italo-franco-suisses, s'appuie en particulier sur l'utilisation de deux isotopes de la molécule d'eau: l'oxygene-18 et le tritium. Le signal d'entrée en oxygene-18 fourni par les precipitations présente une grande variabilité due au contexte orographique et climatique. Dans les aquifères de versant, les circulations préférentielles liées à une fracturation plus ou moins profonde, réalisent une homogénéisation aboutissant à un signal de sortie très tamponné, ce qui explique la stabilité et l'uniformité des valeurs relevées dans le milieu alluvial. L'outil principal permettant une distinction entre les différentes circulations s'est avéré être le tritium, dont les variations saisonnières constituent un excellent traceur des écoulements souterrains.
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Righini, Margherita. "GEOMORPHIC RESPONSE TO EXTREME FLOODS IN ALLUVIAL AND SEMI-ALLUVIAL RIVERS." Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3422781.
Full textAbstract:
ABSTRACT
Extreme floods are one of the major natural hazards that affect Italian territory causing causalities, severe damages to human properties and infrastructures and major economic losses.
High intensity flood events can significantly affect channel morphology with extremely variable magnitude and pattern among river reaches, even within the same catchment, depending on the initial morphological conditions and being a function of the balance between flood driving and channel boundary resistant forces. This work addresses a better comprehension of morphodynamic processes during extreme flood events through the use of integrated and interlinked approaches.
The thesis addresses: i) the documentation and analysis of channel response and its variability during large floods through different morphological settings (i.e., alluvial/semi-alluvial and confined/unconfined rivers); ii) the development of a systematic approach to assess and quantify geomorphic changes; iii) the investigation of the main factors controlling such changes; iv) the development of empirical and conceptual models for the their prediction.
This research presents a quantitative assessment of the geomorphic effects of extreme hydrological events in three Italian catchments recently affected by large floods. The evaluation of channel response is based on an integrated approach that makes a synergic use of two main methodologies employed in the geomorphological study of rivers: remote sensing and GIS analyses, and field surveys. Flood effects detection was carried out by means of a stepwise approach mainly based on multi-temporal GIS analysis of remote sensing data (i.e., aerial photos and satellite images) in synergy with other topographic data (e.g., DEMs, DTMs) integrated by field surveys.
The research was conducted on alluvial and semi-alluvial rivers displaying typical characteristics of mountain streams and covering relatively wide ranges in terms of physiographic and geomorphological setting (e.g., channel width, channel gradient, lateral confinement, human impacts). The study rivers include six tributaries of the Magra River (northern Apennines) with basin areas ranging from 8 to 38 km2, the Posada River and its main tributary (northeastern Sardinia) with a basin area of 680 km2, and the Lierza Creek (Venetian Prealps) with a basin area of 7.5 km2.
Planimetric changes are the main focus of the study. Channel widening was the most remarkable morphological response to the analysed extreme rainfall events, from alluvial unconfined channel reaches subjected to intense adjustments (i.e., very high effectiveness and magnitude) to lower or negligible adjustments in confined semi-alluvial channels. However, in the upstream reaches, generally characterized by high confinement and steep gradients, the flood power was high enough to erode the valley sides. A deeper analysis of channel width changes underlined two different behaviours depending on the initial channel width, showing larger variability in width changes in the narrower reaches than in the wider reaches.
The results of this study reflect the physical complexity of the river system and the complex nature of high-magnitude events, as they show that flood-driven geomorphic changes are controlled by several factors, both morphological and hydraulic ones, which lead to variable patterns of change. The flood peak stream power is often not sufficient to explain satisfactorily the channel response to floods, and inclusion of other factors turned out to be necessary to increase explanatory capability. In particular, a statistical analysis of controlling factors showed that channel widening magnitude depends – besides unit stream power calculated using the pre-flood channel width – on lateral confinement, especially in unconfined alluvial channels with erodible channel beds. Although the highest values in peak unit stream power were observed in confined and partly confined semi-alluvial reaches, the most intense channel widening did not occur in such reaches. Unit stream power – calculated based on the pre-flood channel width – has a major role in determining channel width changes in alluvial reaches, suggesting that most of width changes occurred after flood peak.
The results of this thesis confirm how predicting geomorphic effects of extreme floods in fluvial systems is challenging. However, a robust geomorphological approach as the one deployed here can contribute to i) the identification of the most probable reaches subject to dramatic morphological effects; ii) to define the minimum lateral extension that should be expected by flood erosion; iii) to provide a basis for the definition of sound river management strategies and interventions.RIASSUNTO Gli eventi idrologici estremi sono uno dei maggiori rischi naturali che affliggono il territorio italiano causando la perdita di vite umane, ingenti danni ai beni economici, ai beni privati e alle infrastrutture. Eventi di piena estremi possono modificare significativamente la morfologia dell'alveo con un’elevata variabilità tra tratti dello stesso corso d’acqua, ma anche all'interno dello stesso bacino idrografico, ,in relazione alle condizioni morfologiche iniziali e in funzione dell'equilibrio tra le forze innescanti e le forze resistenti determinate dalle condizioni al contorno dell'alveo. Perciò, il lavoro è volto ad una migliore comprensione dei processi morfodinamici durante eventi di piena estremi attraverso l'impiego di approcci sinergici ed integrati. Il lavoro di tesi è volto i) all’analisi e alla documentazione del comportamento e della variabilità della risposta morfologica in contesti morfologici differenti (in corsi d’acqua alluvionali e semi-alluvionali, confinati e non confinati); ii) allo sviluppo di un metodo sistematico indirizzato alla valutazione e quantificazione delle variazioni geomorfologiche; iii) allo studio dei principali fattori che controllano tali variazioni; iv) allo sviluppo di modelli empirici e concettuali per la loro possibile previsione. Questa ricerca propone di valutare tramite un'analisi quantitativa gli effetti dei processi geomorfologici dovuti ad eventi idrologici estremi in tre differenti bacini idrografici italiani, recentemente colpiti da eventi ad elevata magnitudo. La valutazione della risposta geomorfologica è basata su un approccio integrato attraverso l'uso sinergico delle due principali metodologie impiegate nello studio geomorfologico dei corsi d’acqua, vale a dire l’impiego del telerilevamento e di analisi GIS e il rilevamento sul terreno. L'indagine degli effetti relativi agli eventi di piena considerati è stata effettuata attraverso un approccio stepwise grazie all'integrazione di analisi multitemporali in ambiente GIS di dati telerilevati (foto aeree ed immagini satellitari), in sinergia con altri dati topografici (ad esempio DEM o DTM), e rilievi sul terreno. Lo studio è stato condotto in corsi d’acqua alluvionali e semi-alluvionali che presentano le tipiche caratteristiche di torrenti montani ma con caratteristiche fisiografiche e geomorfologiche differenti (come ad esempio la larghezza e la pendenza dell'alveo, il confinamento e l'impatto antropico) includendo sei affluenti del Fiume Magra (Appennini settentrionali) con bacini aventi aree comprese tra 8 e 38 km2, il Fiume Posada ed il suo affluente principale (Sardegna nord orientale) avente un bacino di 680 km2, e infine il torrente Lierza (Prealpi venete) con un bacino di 7.5 km2. Le variazioni planimetriche rappresentano l’aspetto maggiormente analizzato in questo studio. L'allargamento dell'alveo, la riattivazione della pianura alluvionale e l'erosione dei versanti risultano essere la risposta geomorfologica dominante agli eventi estremi analizzati, con intensità da molto elevata, negli alvei alluvionali non confinati, a bassa o praticamente trascurabile, negli alvei semi-alluvionali confinati. Tuttavia, nei tratti di studio situati più a monte, dove generalmente il fondovalle risulta più confinato, ovvero dove la pianura alluvionale è di limitata larghezza e la pendenza è elevata, il flusso è altamente concentrato tende a causare l’arretramento dei versanti che ne limitano la mobilità trasversale, coinvolgendo nel processo erosivo anche porzioni poste al di fuori dello stesso corridoio fluviale erodibile. Un'analisi più dettagliata delle variazioni di larghezza dell'alveo ha fatto emergere due comportamenti differenti a seconda della larghezza iniziale, mostrando un’elevata variabilità nelle variazioni di larghezza maggiore nei tratti più stretti rispetto ai tratti più larghi. I risultati mostrano che le differenti variazioni morfologiche dovute a tali eventi sono controllate da molteplici fattori, sia morfologici che idraulici, riflettendo la complessità fisica sia del sistema fluviale che della natura di eventi a così elevata intensità. La potenza unitaria della corrente non è spesso sufficiente per l'interpretazione di una determinata risposta geomorfologica, perciò si rende necessario considerare altri fattori al fine di aumentare la capacità esplicativa di tali processi. L'analisi dei fattori di controllo ha evidenziato che la variazione di larghezza dell'alveo dipende essenzialmente da i) il confinamento laterale, specialmente nei tratti alluvionali a fondo mobile, dove il basso confinamento laterale controlla l'allargamento in un fondovalle in cui l'alveo è libero di modificarsi lateralmente, e ii) la potenza unitaria della corrente, calcolata utilizzando la larghezza dell'alveo iniziale (i.e., prima dell'evento). Nonostante nei tratti semi-alluvionali confinati e parzialmente confinati siano stati osservati i maggiori valori della potenza unitaria della corrente, non sono stati rilevati i processi di allargamento più significativi tra quelli osservati. La potenza unitaria della corrente, calcolata utilizzando la larghezza dell'alveo iniziale, risulta invece avere un ruolo maggiore nel determinare il processo di allargamento nei tratti alluvionali, suggerendo altresì che la maggior parte delle variazioni di larghezza si siano verificate successivamente al picco dell’evento di piena. I risultati di questa tesi confermano come la previsione degli impatti geomorfologici sul sistema fluviale rimanga un aspetto di non facile risoluzione. Ciò nonostante pongono l'attenzione sull'importanza di un'analisi geomorfologica quantitativa che può contribuire all'identificazione dei tratti più sensibili a variazioni morfologiche di elevata intensità e alla definizione di azioni di pianificazione volte alla mitigazione del rischio e alla scelta di strategie di gestione ed eventuali interventi.
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Ferdousi, Amena. "Dispersion in Alluvial River." Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3423705.
Full textAbstract:
River pollution is the contamination of river water by pollutant being discharged directly or indirectly on it. Depending on the degree of pollutant concentration, subsequent negative environmental effects such as oxygen depletion and severe reductions in water quality may occur which affect the whole environment. River pollution can then cause a serious threat for fresh water and as well as the entire living creatures. Dispersion in natural stream is the ability of a stream to dilute soluble pollutants. Different types of pollution, such as accidental spill of toxic chemicals, industrial waste, intermittent discharge from combined sewer overflows and temperature variations produced by thermal outflows, may generate a cloud whose longitudinal spreading strongly affects the pollutant concentration dynamics. Pollutants discharging form a point source is easier to control where as pollutant discharging from non point sources arehardlycontrollable and may represent severe threat to the river ecosystem. The longitudinal dispersion coefficient is used to describe the change in characteristics of a solute cloud from an initial state of high concentration and low spatial variance to a downstream state of lower concentration and higher spatial variance. Therefore, in order to correctly estimate the degree of pollutionwithin a stream and ensure an efficient and informed management of riverine environments,a reliable estimationof the dispersion withinthe stream is a crucial concern.
The objective of my research is to develop a mathematical model for determining the dispersion in alluvial river. In order to achieve the goal, a model has been developed which provides an analytical relation for the prediction of the dispersion coefficient in natural streams, given the planimetric configuration of the river and the relevant hydrodynamic and morphodynamic parameters (i.e., width to depth ratio, the sediment grain size, scaled with the flow depth, the Shields stress).
One of the most striking features of alluvial rivers is their tendency to develop regular meandering plan forms. Their geometry is in fact characterized by a sequence of symmetrical curves which amplify over time due to erosion processes at the outer bank and deposition at the inner bank. This planimetric pattern affects both the hydrodynamics of the river and the distribution of bed elevations, as well as its hydraulic response, as the average bed slope is progressively reduced along with the flow cross sections. The flow filed that establishes in meandering rivers has clearly a great relevance on the behavior of the pollutant cloud and hence on the dispersion that drives its microscopic evolution.
To develop a dispersion coefficient predicting model, the analytical models of flow field establishing in the cross section of a straightriver [TubinoansColombini, 1992] and of a meandering river [Frascati and Lanzoni, 2013] aredeveloped. The two dimensional mass balance equation governing the dynamics of a pollutant is then solved using asymptoticexpression and Morse and Feshbach[1953] formalism. Finally, using the two dimensional spatial distributions of the concentration, the flow depth and the velocity, the dispersion coefficient are obtained.
For straight rivers the cross-sectional velocityand the theoretically predicted dispersion coefficients with the field datacollected by Godfrey and Frederick (1970)in two rivers (Clinch River, Copper Creek). The comparison is reasonably good.
The performance of the model is also tested with reference to the predictions provided by the model proposed by Deng (2001). The resultant model is found to give prediction closer to 80% of the experimental data,a much better performance agreement with respect to the model of Deng (2001).
The results of the model developed to estimate the dispersion coefficients in meandering river, have been compared with the experimental data available in experimental and referring to six different rivers. Also in this case the agreement between the dispersion coefficient predicted theoretically and those calculated on the basis of tracer tests is quite good and better than that ensured by the other theoretical and empirical predictors available in literatureLo studio della dinamica di un inquinante convenzionale (e.g., BOD) all’interno di un corso d’acqua naturale richiede la conoscenza del campo di moto e della batimetria che si realizzano nel corso d’acqua stesso, delle modalità di immissione (continua o localizzata, accidentale o sistematica) e delle reazioni chimiche a cui l’inquinante è soggetto. L’obiettivo della presente tesi è quello di caratterizzare la distribuzione spazio-temporale della nuvola di inquinante, in modo da poter valutare i carichi inquinanti e controllare il soddisfacimento, o meno, dei requisiti di legge. In particolare, l’attenzione è stata concentrata sul comportamento dell’inquinante nel cosiddetto campo lontano, ovvero a una distanza dalla sorgente tale per cui l’inquinante si è mescolato verticalmente e trasversalmente, distribuendosi quasi uniformemente sulla sezione. In tali condizioni, ai fini applicativi è sufficiente studiare il comportamento della concentrazione media sulla sezione. Tale comportamento è retto dalla classica equazione dell’avvezione-dispersione la cui soluzione, nel caso di immissione istantanea e localizzata di una determinata massa di sostanza inquinante e tratto di corso d’acqua omogeneo, è data dal classico andamento Gaussiano. La stima del coefficiente di dispersione da utilizzare nella suddetta equazione risulta di fondamentale importanza per una corretta previsione del comportamento spazio-temporale dell’inquinante. La struttura di tale coefficiente, d’altra parte, è strettamente legata al campo di moto che si realizza in un alveo naturale e, in particolare, alle deviazioni rispetto ai valori medi sulla sezione della velocità e della concentrazione. Utilizzando le attuali conoscenza relative al campo di moto in alvei a fondo mobile, nella presente tesi viene derivata una soluzione analitica del coefficiente di dispersione dipendente da parametri in ingresso quali il rapporto larghezza-profondità desumibile dalla geometria della sezione, il diametro dei sedimenti, normalizzato con la profondità della corrente, la pendenza del corso d’acqua. Il problema è inizialmente affrontato nel caso di alveo rettilineo e sezione in equilibrio con il trasporto in cui il fondo varia gradualmente in direzione trasversale. Risulta cos`ı possibile suddividere la generica sezione in una zona centrale, dove la profondità della corrente si mantiene approssimativamente costante, e due regioni di sponda, nelle quali la profondità si riduce gradualmente a zero. Il campo di moto calcolato tendendo conto di questa lenta variazione trasversale del fondo (che consente di semplificare opportunamente l’equazione della quantità di moto), raccordato con quello che si realizza nella regione centrale, unitamente all’equazione del bilancio di massa dell’inquinante, consentono di determinare analiticamente il coefficiente di dispersione. Il passo successivo è stato quello di considerare in caso di alvei alluvionali ad andamento meandriforme. Si tratta di una tipologia di configurazione planimetrica molto comune in natura, caratterizzata da una sequenza più o meno regolare di curve alternate. Sfruttando il fatto che molto spesso la curvatura dell’asse del canale è debole, risulta possibile ottenere una soluzione analitica del campo di moto e della topografia del fondo. Tale soluzione, associata all’equazione del bilancio di massa dell’inquinante riscritta in coordinate curvilinee, opportunamente semplificata sfruttando l’ipotesi di deboli curvature, consente di determinare analiticamente il coefficiente di dispersione. Le stime del coefficiente di dispersione ottenute nei casi di alveo rettilineo e ad andamento meandriforme, sono state infine confrontate con i dati di campo reperibili in letteratura, ottenuti tramite campagne di misura con traccianti. Per entrambe le configurazioni planimetriche analizzate(rettilinea e meandriforme), l’accordo tra coefficienti osservati in campo e i risultati delle previsioni teoriche appare generalmente buono e, comunque, decisamente migliore di quello offerto dalle varie formulazioni semi-empiriche e teoriche attualmente disponibili in letteratura
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Levine, Steven Joel. "Genesis of typic paleorthids and petrocalcic paleargids on the same fan terrace in the Avra Valley near Tucson, Arizona." Thesis, The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_414_sip1_w.pdf&type=application/pdf.
Full text
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Anderson, Stephen. "Differential compaction in alluvial sediments." Thesis, Cardiff University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.536314.
Full textAbstract:
Differential compaction within alluvial sediments results from the inherent juxtaposition of sand, si It, clay and peat on the floodplain. Differential compaction is primarily dependent on (a) the nature of overbank mudstone compaction, and (b) the relative timing of channel and adjacent overbank sediment deposition. Results from the analysis of modern overbank sediments indicate that the near-surface porosity of alluvial overbank sediment Is controlled by the complex interaction of grain shape, grain size, clay content, groundwater fluctuations, evaporation and transpiration, suggesting that the subsequent compaction of these sediments would be an extremely heterogeneous process, with n'o single controlling parameter. Porosity-depth curves derived from modern sediment analysis indicate that a significant amount of compaction occurs during the first few metres of burial. Examination of samples suggest that ·porosity loss may be due to the expulsion of water from the sediment pores, and the rearrangement of grains from an unstable packing arrangement to a more stable one. Early differential compaction will affect floodplain topography, and therefore directly influence the subsequent pattern of facies distribution. However, as significant amounts of compaction have occurred during very early burial, later stages of compaction will have a less marked effect on alluvial stratigraphy than has been previously suggested. In particular, simulation models such as Bridge & Leeder (1979) which suggest that channel "packing" increases with depth may not be entirely correct. If, within an alluvial sequence, there is no compactional deformation of features such as alluvial channel wings, it is unlikely that channel packing will have increased with depth. Studies of the Middle Jurassic alluvial sediments of North Yorkshire and the Cretaceous of the Isle of Wight, illustrate that the effects of differential compaction can be observed on several scale~: (a) channel belt, (b) individual channel or bedform, and (c) microscopic
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Uddin, Jashim. "Soil organic carbon dynamics in two major alluviums of Bangladesh." Thesis, Kingston University, 2016. http://eprints.kingston.ac.uk/35756/.
Full textAbstract:
This study was designed to evaluate the status, distribution, spatial variability, controlling factors, storage, and change in the levels of soil organic carbon (SOC) in two major alluviums of Bangladesh. The two alluviums the Brahmaputra and the Ganges were selected because they occupy a large area of Bangladesh with a wide diversity of agro-ecosystems. SOC levels were studied across the four sub-sites in the aforementioned alluviums at 0-30 cm depths to evaluate their spatial and temporal variability. The sub-sites, Delduar and Melandah, are in the Brahmaputra alluvium. The other two sub-sites, Mirpur and Fultala, are in the Ganges alluvium. Additionally, SOC and total nitrogen (TN) distribution were studied across eight soil profiles (0-120 cm depths) under the two alluviums. The results revealed that the SOC contents were very low in all the sites. The classical statistics showed that the variability of the SOC was moderate across the four sub-sites. The SOC distribution was positively skewed across all the sub-sites except Fultala. A semivariogram model showed there was generally a weak spatial correlation (R2 < 0.5) of SOC in the study sites. A relatively large sampling grid (1600m) and intensive soil management were perhaps responsible for the observed weak spatial dependency. SOC variability is lower across the highland (HL) and medium highland (MHL) sites than the medium lowland (MLL) and lowland (LL) sites. Changes in land use and land cover were also more intensive in the HL and MHL sites than the MLL and LL sites. The reason for low SOC in the HL and MHL sites may be due to their lower inundation level, e.g., land levels in relation to flooding depths, together with greater intensity of use. Temporal variability of SOC datasets revealed that SOC has declined across all the sites during the last 20-25 years due to the intensive land use with little or no crop residue inputs. It is plausible that SOC has declined to an equilibrium level, and further decline may not occur unless land use intensity changes further. The findings show that SOC is positively related to the TN and clay contents in the soils. This is not surprising as SOC is a major pool of TN, and soil clay fraction is known to protect SOC degradation. SOC and TN storage is higher in the surface soil horizon (0-20 cm) than the sub surface soils. Topsoil horizon is tilled and receives greater crop residue inputs which are subsequently mineralized resulting in higher accumulation of SOC and TN. It appears that inundation land types and land management practices may be the major driving factors of SOC storage and distribution across the study sites.
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Loris, Phoebe. "Hydrogeology of the Waipara alluvial basin." Thesis, University of Canterbury. Geology, 2000. http://hdl.handle.net/10092/7655.
Full textAbstract:
The Waipara alluvial basin, located 50 kilometres north of Christchurch on the South Island of New Zealand is experiencing rapid transformation in land use from pastoral farming to horticulture. In the last five years the use of the groundwater resources has increased significantly. Knowledge is lacking about the availability and sustainability of the groundwater resources.
Groundwater resources can be found throughout the basin in the Quaternary Canterbury and Teviotdale Gravels, and the late Pliocene/Early Pleistocene Kowai Formation. The hydrogeological system can be described as a complex network of discrete, lithologically and hydraulically heterogeneous and aniosotropic semipermeable to permeable channels. The physical and hydraulic nature of the aquifers (or water-bearing units) makes identification and characterisation of the resources difficult. However, the resources can be distinguished in terms of the observed hydrogeologic properties (i.e. lithology, yield, transmissivity, and chemistry).
Chemical and isotope sampling indicate that recharge to the basin aquifers is occurring through the uplifted and fractured Tertiary sequences formed along the eastern and western margins of the basin, and through infiltration of local rainfall in the unconfined and semi-confined portions of the aquifer. Groundwater residence times are long (20- 40+ years). Long residence times, slow recharge, and low hydraulic conductivity suggests that if the groundwater resources are not properly monitored and managed, there is great potential for 'mining' the resource(s), or in other words for depleting the resource faster than it can be recharged.
Long term monitoring and management strategies have been recommended for future work to help gain more knowledge and understanding of the Waipara hydrogeological system, and ensure sustain ability for future development.
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Chen, Daqin 1958. "Geotechnical characterization of an alluvial fanglomerate." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276713.
Full textAbstract:
The Department of Energy (DOE) has recently announced that the Superconducting Super Collider (SSC) will soon be built somewhere in the United States. Preliminary geophysical studies indicate that the Sierrita site 35 miles southwest of Tucson has geological conditions that would facilitate construction of the SSC. The Maricopa site southwest of Phoenix is also one of the two potential sites in Arizona. However, several additional geotechnical investigations were required to convincingly demonstrate the suitability of these two locations. The present research program identified the geotechnical properties of the soils at the two sites through various levels of laboratory and field testing. The significance of these results are discussed and recommendations are given.
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Baylis, Erin Julia. "An investigation of the hazard associated with the alluvial fans on the Kaikoura Coast, South Island, New Zealand : a thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Master of Science (Honours) in Physical Geography /." ResearchArchive@Victoria e-Thesis, 2009. http://hdl.handle.net/10063/1192.
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Iwasaki, Yumi. "Assessment of groundwater environment in a paddy-dominated alluvial fan- Case study of Tedori River alluvial fan, Japan -." Kyoto University, 2014. http://hdl.handle.net/2433/189682.
Full textAbstract:
Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第18525号
農博第2082号
新制||農||1026(附属図書館)
学位論文||H26||N4869(農学部図書室)
31411
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 川島 茂人, 教授 星野 敏, 教授 藤原 正幸
学位規則第4条第1項該当
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Aalbersberg, Gerard. "The alluvial fringes of the Somerset Levels." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297642.
Full textAbstract:
Using core lithology and palaeoecological analyses, the vegetational and landscape development and local hydrological conditions since c. 6000 BP in two areas of the Somerset Levels has been studied. Focusing on the former characteristics of the river Brue, the floodplain upstream from Glastonbury and the area near Panborough Gap in Wedmore Ridge were investigated. In the latter area a distinct palaeochannel thought to be the prehistoric course of the Brue is present. Both areas show a similar development with saltmarsh and lagoonal environments until 6000 BP, followed by a prolonged period of Alnus - Salix carr and sedge fens. In the Panborough area freshwater deposition was interrupted by distal saltmarsh and lagoon sedimentation between 2900 BP and 2200 BP. This marine incursion caused stagnation of river discharge upstream which led to the growth of Cladium-rich "tloodinq layers" in the central raised bog area. After embankment of the rivers in the Middle Ages the changed hydrological conditions caused deposition of the upper floodplain clays. Until medieval embankment and canalisation determined its present day course, the river Brue did not have a fixed course but consisted of several small short-lived channels. The palaeochannel in the Panborough area is filled with sediment from the Sheppey while its course is inherited from a tidal channel that was incised between 2900 BP and 2200 BP. Blocked by the raised bog in the west the Brue water took a northerly drainage route, and it seems likely that it contributed to this palaeochannel system. The Brue sediment however was deposited as floodplain and backswamp clays in the Glastonbury area, and the long-held opinion that the palaeochannel is the 'Old river Brue' therefore cannot be maintained. Processes in the coastal region have been inferred from the local hydrological changes and these inferences have partly been verified with a simplified, two-dimensional hydrogeological model.
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Zanre, Dina D. L. "On the mathematics of alluvial river hydraulics." Thesis, University of East Anglia, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262268.
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Ellis, Clare. "The archaeomagnetism of fine-grained alluvial sediment." Thesis, University of Leicester, 1995. http://hdl.handle.net/2381/34928.
Full textAbstract:
Floodplain environments and sediments are frequently associated with human activity. The interpretation of these associations is highly dependant upon alluvial chronology. The absolute dating of recent alluvial sediment therefore has considerable archaeological value and advances our understanding of the relationships between human activities and the landscape. The main aim of this thesis is to explore the potential of archaeomagnetism to date such fine-grained alluvial sediments in a number of different contexts including both 'natural,' (e.g. overbank, levee, channel and fluvial/estuarine) and artificial depositional environments (e.g. fishponds, a millpond and a cistern or well). One of the advantages of archaeomagnetism is that it is the date of deposition, or shortly afterwards that can be determined. The study has confirmed that waterlain sediments can often exhibit a natural remanence magnetisation. Three Italian sediments yielded good remanence data, however, because of the incomplete nature of the Italian archaeomagnetic curve the assignment of dates was tentative but encouraging for the future. Only two of the British sites, Hemington Fields and Dane valley were successfully dated using archaeomagnetism and the reasons for this are discussed. Many sediments do not appear to carry a natural remanence magnetisation because of depositional and post-depositional processes and so a second aim of this thesis is to explore and broaden our understanding of such processes through the analysis of sedimentary fabric. The remaining non-datable British sites were devoid of a remanence due to the affects of a variety of post-depositional processes. The sediment from the Marta and Fiora also revealed that sediment with an initial high magnetic content and that had experienced small scale physical post-depositional disturbance (rather than physico-chemical) can retain a natural remanence magnetisation. The complex nature of fine-grained sediment deposition and post-depositional processes is examined. A third aim of the thesis was to recommend relatively simple procedures for the in-field assessment of sediments with a high probability of being datable using archaeomagnetism. The procedures have been developed from the study of sedimentary characteristics associated with the environments used in this study.