Shallow water equations are widely used to model water flows in the field of hydrodynamics and civil engineering. They are complex, and except for some simplified cases, no analytical solution exists for them. Therefore, the partial differential equations of the shallow water system have been the subject of various numerical analyses and studies in past decades. In this study, we construct a stable and robust finite volume scheme for the shallow water equations over quadtree grids. Quadtree grids are two-dimensional semi-structured Cartesian grids that have different applications in several fields of engineering, such as computational fluid dynamics. Quadtree grids refine or coarsen where it is required in the computational domain, which gives the advantage of reducing the computational cost in some problems. Numerical schemes on quadtree grids have different properties. An accurate and robust numerical scheme is able to provide a balance between the flux and source terms, preserve the positivity of the water height and water surface, and is capable of regenerating the grid with respect to different conditions of the problem and computed solution. The proposed scheme uses a piecewise constant approximation and employs a high-order Runge-Kutta method to be able to make the solution high-order in space and time. Hence, in this thesis, we develop an adaptive well-balanced positivity preserving scheme for the shallow water system over quadtree grids utilizing different techniques. We demonstrate the formulations of the proposed scheme over one of the different configurations of quadtree cells. Six numerical benchmark tests confirm the ability of the scheme to accurately solve the problems and to capture small perturbations. Furthermore, we extend the proposed scheme to the coupled variable density shallow water flows and establish an extended method where we focus on eliminating nonphysical oscillations, as well as well-balanced, positivity preserving, and adaptivity properties of the scheme. Four different numerical benchmark tests show that the proposed extension of the scheme is accurate, stable, and robust.

Title: Barotropic ocean tide model Author: David Einšpigel Department: Department of Geophysics Supervisor: prof. RNDr. Zdeněk Martinec, DrSc., Department of Geophysics Abstract: The main aim of this thesis is developing of a numerical model of an oceanic circulation forced by the lunisolar tidal potential. The circulation is described by the shallow water equations which are derived from the fundamental balance laws assuming that the ratio of the vertical and horizontal dimension of the investigated problem is small, which leads to the formulation of the 2- D task. Furthermore, programs for solving the shallow water equations were written. Their functionality is demonstrated on several examples. The programs include an ephemeridal tidal modul which computes the complete lunisolar tidal potential. Keywords: oceanic flow, shallow water equations, lunisolar tidal potential

Since the late 20th century most people in rural Bangladesh use hand pumped tube wells to extract groundwater as their primary source of water. In 1993 it was officially recognized that many of the Holocene groundwater aquifers contain elevated levels of arsenic (As) and that millions of people in Bangladesh are exposed and at risk for mass poisoning. The need to focus efforts to areas with scarce supply of safe drinking water has raised the need to quickly locate and identify these areas. Mitigation options evaluated in this study focus on 1) how to target As safe aquifers and 2) how to identify As safe tube wells An attempt to target As safe shallow aquifers based on sediment color was evaluated. The majority of 30 new tube wells screened in off-white sand sediments have As safe water with respect to both the WHO and the national guideline, but including the failed attempts to target off-white sediments at shallow depths, the success rate of the method was considered to be too low. This study also attempt to validate platform color as a rapid low-cost screening tool for As by relating platform color to water chemistry in 103 tube wells. Different classification methods were tested to develop recommendations for the future use of this method. The results showed that a simplified color classification was better than a detailed classification at predicting water chemistry of iron (Fe), manganese (Mn) and As. Recently, Mn has also emerged as a possible widespread problem in the Bengal Basin. Although not thoroughly investigated, present evidence indicates that a high concentration of Mn in drinking water affects the intellectual function in children. The occurrence of both low As and low Mn concentrations in shallow aquifers was found to be very unlikely since only one out of 133 tested wells had this water chemistry composition. Instead it was showed that the highest Mn concentrations occur in As-safe aquifers. Therefore WHO should consider reintroducing their previous health based guideline value for Mn to highlight the potential risk of excessive exposure, since more people risk being exposed to Mn when As-safe shallow aquifers are targeted.

The deep mining industry and civil engineering need to perform rock stability analyses during excavation projects. These analyses are closely related with displacements in tunnel contours. The ground reaction curve is a powerful tool to characterize these displacements that is widely used in the New Austrian Tunneling Method. However, the analytical solutions that exist are only applicable under isotropic stress conditions for deep tunnels. This study aims to investigate when it is possible using the analytical methods to determine the ground reaction curves with enough accuracy in the case of shallow tunnels under anisotropic in-situ stress conditions. The method begins with a literature study. After that, with the help of a 2D model, a comparison between the analytical and the numerical solutions for ground reaction curves at different depths and at different initial in-situ stress ratios was carried out. The results show that both crown and floor displacements deviate more from the analytical solution than the wall displacement. The crown and floor can even move upwards under high initial in-situ stress ratios for shallow tunnels. Because of that, the analytical solution of the ground reaction curve at shallow depths under anisotropic stress conditions should not be used. In the case of isotropic stress field conditions for the analysis in this study, the results given by the analytical solution agree with the numerical ones at depths higher than 14 times the radius of the tunnel. On the other hand, the difference between numerical and analytical solutions becomes higher while increasing the initial in-situ stress ratio, even for very deep tunnels. Furthermore, an empirical equation to obtain the displacements of the ground surface, tunnel wall and tunnel crown has been obtained after a multiple linear regression analysis.

Bwaise III in Kampala, Uganda is a densely populated informal settlement with a shallow groundwater table and inadequate basic services. High risk of groundwater contamination will bring health problem to the local residents. In this study, a large dimension (300 m in length) 2D model was developed to depict the hydrogeological condition and to examine the response to different rainfall infiltration rate on the groundwater table. The boundary condition of the drainage system plays an important role in modeling the groundwater flow. The simulation results show that water in the drain will flow into the aquifer when the drain is full, otherwise the drain will act as a sink for ground water. Advective transport of phosphorus results in no pollutants reaching or percolating into the drain. The integration of phosphorous concentra-tion flowing out of Domain 3 (pollutant inlet) corresponds to the infiltration rate and the plume moves faster during the wet season which brings in more phosphorous compared with the dry season. With sorption, all the phosphorus was adsorbed within the top soil. A simplified 3D model was set up to illustrate the flow field. Additional simulation can be undertaken within this 3D frame for more realistic calculation and consistent prediction.

More than two million people in the Chaco-Pampean plain in central Argentina are affected by high As levels in groundwater. The concentrations of As are far exceeding the WHO standard limit for safe drinking water of 0.1 μg/L and the provisional Argentinean limit of 0.5 μg/L. The NE of La Pampa province is one of the areas affected with geogenic As in shallow aquifers within the Chaco-Pampean plain. These aquifers are in closed basins and they are only available water resource of the region for drinking and agriculture purposes. The Pampean aquifer is composed of a multi-layered system of Quaternary loess deposits covered by aeolian sands and also containing layers of rhyolitic volcanic ash, which is considered the primary source of As. Volcanic ash layers can be visible in the shallow sediments or intermixed in the loess. During the weathering of volcanic ash sediments As is dissolved to the aqueous phase and can be quickly adsorbed or co-precipitated on secondary Fe, Al and Mn oxy-hydroxides under favourable conditions. Also, previous more arid climatic conditions have led to the formation of carbonate "calcrete" layers in the top sequences of the loess and this has affected the geochemistry of the aquifer. Two sites were investigated in the NE of La Pampa province in order to assess (i) the quality of groundwater for drinking water use, (ii) the distribution of As and other trace elements in shallow aquifers and (iii) to understand better the factors controlling its mobility in groundwater. The results showed that groundwater was circum-neutral to alkaline and under moderate oxidizing conditions. The predominant groundwater composition was of Na-HCO3 for fresh water and Na-Cl-SO42- for brackish water types. High salinity levels are evidenced by the high Electrical Conductivity and might be explained by to the high evaporation rates. Groundwater sampled in both areas was enriched with As, F and other trace elements at different ranges of concentration. From the total As concentrations, arsenate As(V) predominated over arsenite As(III) species. Shallow groundwater is also enriched with fluoride exceeding the WHO standard limit of 1.5 mg/L and placed in the same As hotspots. One possible factor controlling the mobility of As is the high pH of groundwater, which is controlled by the carbonates equilibrium. Under this high pH conditions As is less strongly bind to Fe, Al and Mn oxy-hydroxides and can be easily mobilized to groundwater when other competing ions are getting adsorbed on the surface sites of binding minerals.

Denna rapport har sin utgångspunkt på skapandet av en maskininlärningsalgoritm för att kunna klassificera ett fysiskt fall av en person. En DC Kapacitiv MEMS-accelerometer (BMA250) kombinerat med en Tinyduino Processor (Atmega328P) används för datainsamling. Programmering av processorn och maskininlärningsalgoritmen skrivs i C++ och ANN (Artificiell Neuralt Nätverk) används för att klassificera det fysiska fallet. ANN kan approximera ett värde som tyder på ett falskt fall efter 10 000 träningssekvenser inom 5% av ett teoretiskt värde som tyder på ett resultat med 100% säkerhet och 0,0005% felmarginal. Ett teoretiskt värde som tyder på ett faktiskt fall kan klassificeras efter 5000 träningssekvenser inom 5% av det eftersökta värdet med 100% säkerhet och 0,0045% felmarginal.

After approximately 25 years of using open drains in the Lewiston Area, Utah, the water table has not changed appreciably from what it was in 1921 when Hart and Adams (4) conducted their drainage investigations. It is still only about three feet below the ground surface. This is not effective drainage, meeting neither of the two primary drainage requirements of an arid or semi-arid agricultural region, namely; preventing an accumulation of excessive water within the depth of soil required for optimum growth of plant root systems, and maintaining the water table at a depth below the ground surface greater than the maximum height capillary water can rise, carrying any harmful salts that may be present in solution.

Significant phosphorus transport is occurring in the groundwater surrounding Pineview Reservoir. A set of investigations was completed to identify factors contributing to phosphorus mobility. Water quality monitoring was conducted to understand groundwater characteristics and phosphorus movement. Several water quality parameters were evaluated to specifically determine whether septic systems influence groundwater quality. Results indicate that septic systems pollute at least two locations in the aquifer around the reservoir. Given this information, it may be necessary to implement advanced septic system treatment options to reduce the amount of phosphorus in groundwater. Experiments were conducted on two aquifer sediment types to identify factors important for phosphorus mobility. Coarse-grained sand and fine-grained sediments were evaluated, and results showed that phosphorus in both sediments is associated more with calcium minerals than with iron and aluminum minerals. Results suggest calcium is an important factor for immobilizing phosphorus in groundwater at Pineview Reservoir. Iron and manganese oxide concentrations are important for decreasing phosphorus mobility, and experiments showed higher amounts were observed in fine-grained sediments than for coarse-grained sediments. Results of geochemical modeling exercises suggested that sediments may have limited sorption capacity, although at one site, the formation of calcium minerals may provide a continuous source of additional sorption material. Because of suspected septic system influence, the effect of dissolved organic matter on phosphorus mobility was evaluated through a series of laboratory studies. Dissolved organic matter was collected from Pineview Reservoir and used in experiments. Results showed that the presence of dissolved organic matter affected phosphorus sorption minimally, and does not explain P mobility in the shallow unconfined aquifer at Pineview Reservoir.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第17865号 / 工博第3774号 / 新制||工||1577(附属図書館) / 30685 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 牛島 省, 教授 角 哲也, 准教授 米山 望 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM