The Diploma thesis deals with the assessment of global and local stability of the masonry gravity dam Pastviny, for two load conditions. The first part consists of a present state review describing selected masonry dams in the Czech Republic and abroad. Further on a conceptual and mathematical formulation of the seepage flow and strain-stress problem are stated. The case study is focused on the practical application of formulated problems on the Pastviny dam. Firstly the available data have been assembled and processed. Global and local safety of the dam was assessed for the selected most vulnerable profile of the dam body. In the final chapters 5, 6 and 7, the seepage flow, stress and strain have been calculated and graphically displayed. Finally global and local stability have been assessed and completed with final summary of the results and concluding remarks.

A public interface for the infrastructure of Hartbeespoort Dam Water sustains all living things on this earth and has a huge impact on the natural environment. Water is the most valuable natural resource on this earth. It is vital to humans' existence. It is why we have evolved to the point that we are now and if we do not appreciate it, it will be our demise. Water has the ability to adapt and change as different natural systems interact with it, it allows a constant balance to remain. Humans have broken the delicate balance of water supply and demand, detrimentally affecting the natural systems that support us. Since the start of the industrial era our cities have grown at an exponential rate. The development of cities has impacted negatively on natural systems. This has led to a concomitant disconnection between man and nature and has divorced humans from an understanding of the role and importance of natural water systems. . We have forgotten the positive effects that we experience when directly engaging with water as we live in environments often far from nature; rarely experiencing it fully. Our physical control of natural resources has led to a physical disconnection and under appreciation of these precious resources. This project aims to reconnect man and nature to create a new paradigm where humans value our natural resources and, in particular, water. A re-appropriation of water infrastructure through an architectural interface that fulfils cultural, social and economic functions to create a positive recreational space that celebrates water and its importance in our h eritage. T he intention is to c reate a p roductive infrastructure that facilitates exchanges between site, existing infrastructure and the user. / n Publieke skeidingsvlak vir die infrastruktuur van die Hartebeespoort Dam omgewing. Water onderhou alle lewe op aarde en het 'n groot impak op die natuurlike omgewing. Water is die belangrikste natuurlike hulpbron op die aarde en is van die uiterste belang vir die mens se voortbestaan. Dit is hoekom ons die punt bereik het waar ons nou is. Dit sal ons ondergang beteken as ons dit nie bewaar en waardeer nie. Die mens het die delikate balans van aanvraag en watervoorsiening versteur tot nadeel van die natuurlike sisteme wat ons onderhou. Sedert die begin van die industriele tydperk het ons stede eksponensie?l vergroot. Die ontwikkeling van stede het 'n negatiewe impak gehad op ons natuurlike omgewing. Dit het gelei na 'n gepaardgaande diskonneksie tussen mens en natuur en het die mens se begrip van die rol en belang van natuurlike waterbronne negatief be?nvloed. Omdat ons in omgewings woon v?r verwyder van water en dikwels van die natuur kom ons nie direk met water as lewensmiddel in ons omgewing in kontak nie. Ons fisiese beheer van natuurlike bronne het gelei tot die skeiding en onderwaardeering van hierdie kosbare bronne. Die doel van die projek is om mens en die natuur bymekaar te bring en 'n nuwe paradigma te skep waar die mens sy natuurlike bronne, en in die besonder water, waardeer. 'n Nuwe benadering tot waterinfrastruktuur deur 'n argitektonise wisselwerking wat kulturele, sosiale en ekonomiese funksies bymekaar bring om 'n positiewe onspanne ruimte te skep waar die belang van water as 'n erfenis vier, is nodig. Die doel is om 'n produktiewe infrastruktuur te skep wat uitruiling tussen die terrein, die huidige infrastruktuur en die gebruiker bymekaar bring. / Mini Dissertation (MArch (Prof))--University of Pretoria, 2016. / Architecture / MArch (Prof) / Unrestricted

Masters of Science / Radon (222Rn) has been identified as an important factor that could result in a health hazard by studies all around the world. The health risks can be minimised by preventive measures where radon is highly concentrated as in some mines and homes. A study in the diffusion of the inert gas, will give us a better understanding of its possible pathways through soil into the air surrounding mine dumps where the radon releases can become hazardous. Measuring and modelling the radon concentrations in the mine dump soil, can help to deduce the radon flux to identify the problem areas for rehabilitation especially in the cases of gold and uranium mine tailings.

The dangerous hydraulic conditions that can form downstream of a low-head dam were investigated. These dangerous hydraulic conditions have been the cause of hundreds of drowning incidents since the construction of the first low-head dams. Two primary objectives were identified for this study, each of which were primarily performed using the Computational Fluid Dynamics software, Flow-3D®, with physical models used to verify the numerical results. The first objective was the identification of a risk factor made up of easily measured parameters that could accurately predict when the dangerous hydraulic conditions are present at a low-head dam. The risk factor that was found to achieve this objective was calculated as (hu - hd)/P, where hu and hd are the upstream and downstream water depths, respectively, and P is the dam height. For the flat-topped dams tested, the dangerous condition was present within the range of risk factors from 0.343 to 0.708. For the ogee-crested dams tested, the dangerous conditions were present between risk factors of 0.093 and 0.798. The second objective was to identify possible remediation options that would be capable of eliminating the dangerous hydraulic conditions, therefore reducing risk to the public. It was also desired to keep the options easily and inexpensively implemented. Two different remediation options were found to this end, and consisted of either upstream facing ramps spaced along the width of the channel below a low-head dam, or spaced platforms protruding from the downsteam face of the dam slightly below its crest. Three different designs of each configuration were tested, with those for the ramp configuration being identified as R1, R2, and R3. The platform designs were identified as P1, P2, and P3. The options were evaluated based on how long it took for human dummies introduced into the flow to pass through the high risk region of the simulations, with the maximum allowed time being 50 seconds. Any test in which a dummy remained in the danger region for longer than 50 seconds was deemed ineffective. The option found to perform the best was the P2 design, which had an overall performance time of about 17.4 seconds.

In a vast majority of cases, seepage barriers increase the reliability of dams. However, it is important to recognize that seepage barriers often drastically increase hydraulic gradients around the boundaries of the barrier, and through any windows or defects in the barrier. The result is increased water pressures and hydraulic gradients behind and around the barrier. These increased pressures and gradients have potential to provide the catalyst for initiation of several modes of internal erosion that were either unlikely or less likely without the seepage barrier. As a consequence, seepage barriers give rise to the potential for additional mechanisms of internal erosion and piping in the dam and the foundation. Mechanisms of erosion and piping that are uniquely related to seepage barriers have been investigated through review of measured performance of existing dams, and through analytical studies. A compendium of 30 case studies of dams that have had seepage barriers in place for over 10 years has been assembled, and observations and insights garnered from these case studies were compiled. Finite element seepage and deformation analyses have been performed to provide better understanding of the performance of seepage barriers and the mechanisms that affect their performance. Based on the findings from the case studies and analyses, potential failure modes specific to dams with seepage barriers were identified, and the sequences of events required for the propagation of these failure modes were developed. The observations and insights acquired in this study were distilled into conclusions regarding the long-term performance of dams with seepage barriers. The information derived from this study will be useful in 1) assessing the potential for internal erosion and piping developing in dams with seepage barriers, 2) designing to minimize that possibility, and 3) assessing the risks associated with these mechanisms of erosion and piping. It is envisioned that the results of this study will provide dam owners and engineers with a better understanding of the issues involved with dams having seepage barriers and that this understanding will lead to improved practices in assessing, designing, and monitoring of dam seepage barriers. In addition, by improving the means by which seepage barriers can be assessed and designed, it is hoped that the confidence level that dam engineers have with regard to properly designed seepage barriers will be increased, and that properly designed seepage barriers can be viewed as safe and viable alternatives for mitigation of seepage problems. / Ph. D.

Aquatic invasive species are a widespread issue throughout the central United States. Black Carp (Mylopharyngodon piceus) are an aquatic invasive species and are an issue due to their unknown ecological and biological impacts that they may cause to the environment that they invade. Determining movements of an aquatic invasive species such as dam passage or inter-river movement may aid in agency efforts to reduce the spread of an invasive or implement strategies to mitigate its potential expanding range. In this study, I used otolith microchemistry paired with water samples to infer movement and dam passage of Black Carp between eight study regions within the Mississippi River basin. A total of 127 Black Carp otoliths were used and 112 (88%) were classified as immigrants, 14 were classified as potential residents, and one otolith was vateritic so no inferences about movement could be made for that fish. Of the 112 fish classified as potential immigrants, 102 (91%) showed signs of upstream dam passage, and the average instance a Black Carp was inferred to move between rivers was 7 times during their lifetime (SD ± 6.23). These results show that Black Carp may exhibit frequent occurrences of inter-river movement throughout their lives and have high instances of dam passage associated with their movement. This paper presents the first confirming evidence of lock and dam passage by Black Carp, although the apparently expanding range of the species in recent years based on reported captures suggested that lock and dam passage had likely occurred. Evidence of frequent upstream movement and lock and dam passage suggests that future studies should evaluate the efficacy of potential deterrents at locks and dams for preventing or reducing upstream passage by Black Carp.

No description available.

No description available.

El río Colorado se ubica en la parte Norte de la Patagonia argentina y atraviesa con dirección Oestenoroeste - Sur-sureste un sector del país de condición árida y semiárida ubicado entre la Cordillera de los Andes y el océano Atlántico, con un recorrido cercano a los 1.000 km. Esta tesis doctoral aborda el estudio de las características hidrológicas y el estudio específico de las variaciones en el diseño de drenaje de un tramo testigo ubicado en un área predeterminada por su cartografía secuencial y fiable en relación con las posibles variaciones hidrogeomorfológicas. Dentro de la problemática general que presenta el río Colorado, se tuvo en cuenta la función del río Curacó, último tramo de la gran cuenca Desa-guadero Salado Chadileuvú, a la que le da carácter de exorreica. Las periódicas activaciones del Curacó crean serios problemas de salinidad en las cuencas media y baja del Colora-do, parcialmente mitigados en la actualidad por la represa Casa de Piedra. El levantamiento del dique Casa de Piedra, sobre la parte final del alto valle, alteró drásticamente el comportamiento del río en cuanto al arrastre de sólidos. Por acción de su gran embalse se produce la deposición del mate-rial trasportado en suspensión, dándole una nueva condición física -y en parte también química- a las aguas emergentes del dique, que han dejado en el lago las arcillas y el limo que trasportaban. Esos materiales, antes de existir el dique, se depositaban aguas abajo e impermeabilizaban naturalmente los canales en las áreas de regadío de los valles medio e infe-rior. El agua que vierte Casa de Piedra, casi carente de sedi-mento, tiene una capacidad erosiva mayor que la que fluye antes del embalse; esa condición permite reducir el tiempo de formación de meandros con respecto a sectores de aguas arriba de la presa. Esas condiciones han generado también el fenómeno conocido como aguas claras. El estudio ordena en el tiempo y el espacio las variaciones de curvas y meandros del tramo testigo, cuantificándolas. Aunque también se han visto alteradas las curvas de caudal y salinidad es en el gasto sólido donde el dique Casa de Piedra ha provocado los cambios más visibles y fundamentales en el ser y quehacer del río. La curva resultante de los nuevos valores refleja la situa-ción con respecto a la anterior y marca una fuerte disminu-ción en el acarreo. Esta tesis es además un aporte a poste-riores investigaciones interdisciplinarias, especialmente en el campo de la hidráulica y la geomorfología fluvial, dos disci-plinas bajo las cuales el río Colorado ofrece un amplio campo de estudios. El trabajo detecta, determina y cuantifica los cambios físicos y humanos generados por la presencia del dique, algunos ya evidentes y otros en trance de serlo. / The construction of Casa de Piedra dam, in the final stretch of Colorado river high valley, radically modified down waters the hydrologic river course, specially as regards sediment transport, the majority of which settles in the lake. Conse-quently, waters the dam distributes, contain a remarkable erosive capacity, and accelerate down waters hydrographic processes, increasing river meandering and bringing about what is known as the clear waters phenomenon causing adverse effects on watering zones. With the purpose of checking the fact in a quantitative way, cartographies from a certain stretch were taken, being this stretch considered a witness one in periods around 25 years, assessing meanders appearance and disappearance, and comparing these quantities with the variation -in the same sense-, that took place since Casa de Piedra start up. The quantities were sig-nificant considering the relatively short time gone by. The fact was checked in a new aero - photographic flight, according to which, in a shorter lapse, meanders number increased again in the witness stretch.

Water is an integral part of agricultural practices, with agriculture being the largest user of surface water in the United States. Agriculture's reliance on surface water is strengthening as climate change and growing populations are stressing irrigated croplands. This surface water is primarily stored by a complex network of dams, but despite our reliance on surface water for irrigation, we lack a spatially detailed record of irrigation dam command areas. Therefore, we assigned irrigation command areas to the approximately 1,100 large irrigation dams in the continental United States by combining a tiered assignment strategy with field level infrastructure and agricultural data. We showed that these large irrigation dam command areas are responsible for 10.7 million acres of cropland. This translates to approximately 13.3 billion dollars of crops annually that depend on these large irrigation dams for water. The high-resolution, crop specific assignment of these command areas allows for water scarcity assessments that can be used for better water management decisions to address the changing environmental conditions and public demand pressuring the nation's agriculture and water infrastructure. / Master of Science / Agriculture depends heavily on surface water stored by large dams, especially in the face of climate change and population growth. However, the spatial distribution of croplands that rely on these dams is poorly known. We mapped the irrigation command areas of around 1,100 large dams in the continental US using a combination of field-level data and a tiered assignment method. We then traced the agricultural products from these areas to their domestic and international markets. We found that large dams support 10.7 million ares of cropland and 13.3 billion dollars of crop value annually in the US. Our high-resolution mapping of irrigation command areas enables more accurate assessments of water scarcity and reveals the local and distant connections between water infrastructure and its users.