Sedimentation in dams is a natural process depending on various factors over a period of time. Sediments influence both total capacity of dam's surface and also relief of bottom. This thesis deals with amount of sediment in Fojtka dam and with change of its bottom's relief in past 109 years since its establishment. There was conducted measuring using an echosounder in a boat. Final output derived from this experiment was a point layer including 5500 point items. Subsequently there was executed a measurement of dam's shoreline using GPS device. Data were processed in ArcGIS software, then reduced and edited to be used for interpolation tools of ArcToolbox. In order to select the most accurate interpolation method, there were created validation data, which were compared with interpolated data. The best results have been achieved by interpolation method Kriging and TIN in resolution 0.5 m. Original maps were vectorized for comparison with current condition. Created validation data were compared in order to show accuracy of particular interpolation. The most useful evaluated method for gained data was TIN method in resolution 0.5 m. TIN method was applied in both data sets for 2D and 3D bottom relief visualization and also for calculation of actual water volume and area of water surface of the dam. Difference in bottom's relief of Fojtka dam showed capacity reduction about 6,7 % and reduction of water surface area about 3,2 %. Regular extracting of sediment in reservoir located above the dam causes this relatively small silting ratio.

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This thesis adopts a geoarchaeological approach to palaeoenvironmental research in the Konya basin of South-Central Turkey. It involves the analysis of sediment sequencesth rough cultural and alluvial depositsa crossa broad alluvial fan which has developed on the southern edge of the basin since the beginning of the Holocene. Sediments have been analysed by mineral magnetics, particle size, carbonate and organic matter content, and grouping into lithological units has been aided by statistical techniques including principal components analysis and discriminant analysis. Resultso f the analysis have shown a complex sequenceo f deposition across the alluvial fan throughout the Holocene, and within the sequences a number of archaeological sites ranging in date from the Early Neolithic to the Byzantine periods have been identified as being established on various land surfaces. During the early to mid Holocene, the predominant alluvial deposit across the fan was a fine-grained, heavy backswamp clay, deposition of which was time transgressive, i. e. area of deposition changed over this period as the course of the depositing river migrated laterally, and up/down fan. Evidence from the largest and earliest site studied, I; atalh6yiik, where archaeological excavation has recently recommenced, shows that the site was established during the Early Neolithic in an actively flooding alluvial environment. This has implications, not only for the populations inhabiting the site, but also for the wider reasoning behind the establishment of early agricultural settlements in the Near East. Other sites in the area up to the Early Bronze Age have also been seen to have been established in actively depositing alluvial settings. Shortly before c. 4000 BP there was a permanent change in the nature of alluvial deposition, with the heavy backswamp clay being replaced by a less fine-grained deposit of different origin. This initial change was concurrent with an apparent depopulation of the alluvial fan and a relationship between the two phenomena is possible. More importantly, there appear to have been major population changes and increased human influence on the environment of both the fan catchment and the wider region subsequent to these phenomena. Such changes appear to have had a long-term effect on the fan environment as the nature of the alluvial deposition remained relatively unaltered between these events and intensive irrigation schemes which restricted alluvial deposition in the early twentieth century.

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I seek to reconstruct the balance between sediment storage and yield across multiple drainage basin scales in a large (1 230 km2) watershed in the Northern Cascade range, British Columbia and Washington. Chilliwack Valley and surrounding area has been the site of numerous studies that have detailed much of its Quaternary sedimentary history. In the present study this information is supplemented by reconstruction of the morphodynamic trajectory of the river valley though the Holocene Epoch, and development of a sediment transfer model that describes the relaxation from the Fraser glaciation. The total Holocene sediment yield is estimated from basins across several scales using field and remotely sensed evidence to constrain the historical mass balance of delivery to higher order tributary basins. Rates of hillslope erosion are estimated using a diffusion-based relation for open slopes and delimitating the volume evacuated from major gully sources. Digital terrain models of paleo-surfaces are constructed to calculate total sediment erosion and deposition from tributary valleys and the mainstem. Chilliwack Lake has effectively trapped the entire post-glacial sediment load from the upper catchment (area = 334 km2), allowing to compare this "nested" system with the larger catchment. Rates of lake sediment accumulation are estimated using sediment cores and paleomagnetism. These are compared with accumulation rates in the terminal fan inferred from radiocarbon dating of fossil material, obtained by sonic drilling in the apex gravels. A sediment budget framework is then used to summarize the net transfer of weathered material and glacial sediments from the hillslope scale to the mainstem. The long-term average sediment yield from the upper basin is 62 +/- 9 t/km2/yr; contemporary yield is approximately 30 t/km2/yr. It is found that only 10-15% of the material eroded from the hillslopes is delivered to mouths of the major tributaries; the remaining material is stored at the base of footslopes and within the fluvial sedimentary system. Since the retreat of Fraser Ice from the mouth of the valley, Chilliwack River delivered over 1.8 +/- 0.21 km3 of gravel and sand to Vedder Fan in the Fraser Valley. In the sediment budget developed here, roughly 85% of that material is attributed to glacial sources, notably the Ryder Uplands and glacial valley fills deposited along the mainstem, upstream of Tamihi Creek. In tributary valleys, local base-level has fallen, leading to the evacuation of deep glacial sedimentary fills. Many of the lower reaches of major tributaries in upper Chilliwack Valley (e.g. Centre and Nesakwatch Creeks) remain primarily sediment sinks for slope-derived inputs, since base-level fall has not been initiated. In distal tributaries (Liumchen, Tamihi and Slesse creeks), paraglacial fans have been incised or completely eroded, entrained by laterally active channels. A transition from transport-limited to supply-limited conditions has been effected in many of these reaches. Slesse Creek has struck an intermediate balance, as it continues to remobilize its considerable sediment stores. It functions today as the sedimentary headwaters of Chilliwack Valley. Using grain size data and fine-sediment geochemical data gathered from Chilliwack River over the course of several field seasons, a simple finite-difference, surface-based sediment transport model is proposed. The aim of the model is to integrate the sediment-balance information, as inferred from estimates of hillslope erosion and valley storage, and physical principles of sediment transport dynamics to reproduce the key characteristics of a system undergoing base-level fall and reworking its considerable valley fill during degradation. Such characteristics include the river long profile, the river grain-size fining gradient, the percentage of substrate sand, and the diminution of headwater granite lithology in the active load. The model is able to reproduce many of the characteristics, but is not able to satisfy all criteria simultaneously. There is inevitably some ambiguity as to the set of parameters that produce the "right" result, however the model provides good insight into long-term interactions among parameters such as dominant discharge, grain size specifications, abrasion rates, initial topography, hiding functions, and hydraulic parameters. / Arts, Faculty of / Geography, Department of / Graduate

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No description available.

Benzodiazepines are the most commonly prescribed group of psychotherapeutic pharmaceuticals on a global scale and have been on the market since the 1960s. Benzodiazepines remain in the aqueous effluent from sewage treatment plants and have been found in natural aquatic environments. The aim of this study was to investigate if there is benzodiazepines in natural sediment from Lake Ekoln situated downstream River Fyris in Uppsala, where previous studies have detected high concentrations in the water. The study tested following hypotheses: (1) benzodiazepines are accumulating in sediments; and (2) breakdown of benzodiazepines is slow in sediment resulting in them being preserved in sediments that are several years/decades old. An extraction method for sediment was developed followed by liquid chromatography-tandem mass spectrometry for analysis of oxazepam, alprazolam, clonazepam, flunitrazepam, diazepam and prazepam. All investigated benzodiazepines occurred in the sediment of Lake Ekoln; hence, in line with hypothesis 1, benzodiazepines are accumulating in natural sediments. Further, all benzodiazepines were found in the upper 10 cm of the sediment and oxazepam, clonazepam and diazepam was found at depth below 20 cm, corresponding to an age of more than 20 years indicating that benzodiazepines resists degradation processes in sediment and are persistent for decades as predicted by hypothesis 2. To my knowledge this is the first study demonstrating that benzodiazepines are accumulated and preserved in natural sediments.

Magister Scientiae (Integrated Water Resource Management) / River catchments in agricultural areas are strongly influenced by runoff from cultivated or grazed fields, and nutrient loading of these fields can result in large quantities of nitrates and phosphates being transported to rivers in surface runoff. In intensively farmed areas, nutrient loading is often so high that large quantities of nitrates and phosphates are transported to streams in surface runoff. Within these areas, strips of natural riparian vegetation and wetlands are critical in providing nutrient uptake functions that can reduce the load entering streams. A wetland can be a source, sink or transformer of nutrients, where fine sediments such as silt and clay have the ability to store and trap considerable amounts of phosphorus through adsorption and precipitation processes. Therefore, the determination of phosphorus adsorbed to fine sediment is important in understanding the role and value of wetlands in agricultural landscapes, and is the main focus of this study. The aim of the study is to evaluate an indicator-based approach, WET-EcoServices, to assess wetland sediment and phosphate trapping, through comparison with field survey data. The study focuses on spatial analysis and field survey of three Hydrogeomorphological (HGM) units classified for the Wiesdrift wetland on the Nuwejaars River, Cape Agulhas. The three HGM units are classified as: a floodplain wetland at the inlet of the system, a channelled valley-bottom wetland towards the middle part of the system and a floodplain wetland towards the outlet of the system. In-field observations were recorded for hydrogeomorphic and vegetation characteristics for each HGM Unit. AstroTurf mat sediment samples, grabbed channel bed and floodplain sediment samples were analysed for particle size and orthophosphate concentrations, while suspended sediment masses were recorded from three pairs of time-integrated sediment samplers located near the inlet, near the middle, and near the outlet of the wetland. Statistical analysis showed that orthophosphate concentrations are associated with fine sediment. Thus, the orthophosphate concentrations follow the distribution of silt on the Wiesdrift wetland. The dominant vegetation along transect 2, at which the highest concentrations of orthophosphate was found, is occupied by Typha capensis and Cyperus textilis. The percentage of fine sediment (silt) ranged between 0-37%, where the remaining percentage was sand. There was also a significant positive correlation between orthophosphate concentration and silt (Spearman’s rank-order correlation: rs = 0.692, N = 70, P < .001). The largest total sediment amount was found at Outlet 1 and Outlet 2 in the HGM unit 3 of the Wiesdrift wetland, with a value of 0.653 g. Overall, orthophosphate concentrations ranged between 0 mg/kg and 31320 mg/kg within the Wiesdrift wetland. WET-EcoServices determines an average score for phosphate trapping from on-site indicators such as hydrological zones, vegetation structure and soil texture/permeability. The dispersal of fine sediment and associated adsorbed phosphate is more complex than can be determined by a tool like WET-EcoServices because the tool captures the long-term mean conditions of a wetland system that determines the overall uptake of phosphates over extended time periods, thus future wetland assessments is recommended to take place over a longer period than this study. However, the field results of orthophosphate distribution are generally consistent with the findings from WET-EcoServices, further motivating for the use of the tool in wetland management applications.

Ports and waterways are vital to the economy of the United States. In the contiguous United States, there are some 25,000 miles of channels and over 300 ports. Together, this system carries 2 billion tons of freight with a value of over $700 billion annually. Ninety percent of all United States imports and exports travel through these ports and waterways. Dredging of these waterways in the United States costs over $1 billion annually. As ship draft increases, more dredging would be required to keep these ports and waterways open. Fine sediments are very common in these systems and have properties that can reduce dredging efficiency, including easy resuspension into the water column and cohesion among individual particles. Fluid mud is a high concentration aqueous solution of fine sediments that exhibits unique properties, including movement under gravity. A numerical model of fluid mud could be used to predict sediment fate as well as evaluating potential channel modifications to reduce dredging. The goal of this research is to test the flow of fluid mud under shear from the water column and develop a numerical model to simulate the transport of fluid mud. First, laboratory experiments are conducted to ascertain the effects of shear from the water column on the fluid mud layer. Next, a finite element numerical model is developed to simulate the physics of fluid mud, including any effects from shear over the mud layer. Results from the numerical model are compared to laboratory experiments, and the fluid mud model is developed for easy linkage to existing hydrodynamic models for forcing information.