M.Sc. / Please refer to full text to view abstract

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15344号 / 工博第3223号 / 新制||工||1485(附属図書館) / 27822 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 細田 尚, 教授 後藤 仁志, 准教授 米山 望 / 学位規則第4条第1項該当

Prof. A. Avent-Oldewage

The Rietvlei Dam near Pretoria, South Africa, provides drinking water for the city and for the wild life in the Rietvlei Nature Reserve, and is also used for recreational fishing. The dam is part of the Sesmyl Spruit system, which has a history of pollution, the major sources of which are industrial, agricultural and sewage from informal human settlements upstream of the reserve. With a large wetland separating the upstream Marais Dam and the Rietvlei Dam, the system has a high conservation priority status because of the high number of bird species that breed and roost in the various habitats. As part of a big aquatic health project in the Zoology Department, Rand Afrikaans University, aimed at finding suitable biomarkers for water quality monitoring in the system, this study was done to identify the major internal helminth parasites of the sharptooth catfish, Clarias gariepinus, that can be used in fish health assessment studies, and to determine their prevalence and intensity in the Rietvlei Dam. Fish were collected during one sampling survey and examined for endoparasites, also noting any ectoparasites that are recorded in routine fish health studies. Five species of helminths were identified: the adult cestodes, Polyonchobothrium clarias (intestine and stomach), Proteocephalus glanduliger (anterior intestine), the adult nematode Procamallanus laevionchus (stomach), larvae of the nematode Contracaecum sp. and many trematode metacercariae encysted in the muscles, of which only Ornithodiplostomum sp. was successfully excysted and identified. This trematode is recorded in South Africa for the first time, but could not be specifically identified because the reproductive system was still immature. Examination of piscivorous birds in the area or experimental infection of young birds are the only means by which the adult trematodes can be obtained. The adult cestodes and nematodes had specialised structures for attachment to the stomach and/or intestinal mucosa, adaptations associated with pathological effects in the host. Polyonchobothrium clarias had a crown of 26-30 hooks on its rostellum, and this number differs from those of specimens described from catfish in other African countries. Scanning electron microscopy showed that the rostellum of the P. clarias specimens from Rietvlei Dam was different from that of specimens from other localities in South Africa. Proteocephalus glanduliger in C. gariepinus from Rietvlei Dam differed in strobila size and size of glandular organ from specimens described by Janicki (Egypt) and Mashego (South Africa), the present specimens being much longer but with smaller glandular organs. Procamallanus laevionchus is a common parasite of catfish from many African countries, including South Africa, and scanning electron microscopy showed some form of transverse markings and presence of papillae-like structures at the posterior end of female specimens, an observation which was not described in previous studies. Larval Contracaecum are also common in C. gariepinus and other fish species, and adults have been identified in several species of fish-eating birds from South Africa. The sample size of fish collected in this survey was too low for a full health assessment index (HAI) study to be undertaken. Polyonchobothrium clarias and Contracaecum, however, were highly prevalent in the host species, and Contracaecum and Ornithodiplostomum occurred at high intensity (up to 44 and 140 respectively). Endoparasites of C. gariepinus can therefore be used in the fish HAI as a bioindicator of water quality. Only two ectoparasitic species were found on C. gariepinus: Argulus japonicus (skin and fins) and Lamproglena clariae (gills). Most water quality variables from the dam were within the target limits recommended by the Department of Water Affairs and Forestry, but the levels of inorganic nitrogen (nitrate and ammonia) and phosphorus (orthophosphate) exceeded the limit. If uncontrolled, these may lead to eutrophication of the dam. With the parasite species and diversity known, it is recommended that fish health assessments should be conducted along pollution gradients in the system to determine whether it can be incorporated into the suite of biomarkers for water quality monitoring of the Sesmyl Spruit system. / Prof. A. Avent-Oldewage

A large sportfishery that targets both smallmouth (Labeobarbus aeneus) and largemouth (Labeobarbus kimberleyensis) yellowfish exists in South Africa. Both species have high conservation priority, and no assessments documenting the effect of angling on L. aeneus and L. kimberleyensis have been undertaken. The overall aim of this study was to provide an assessment of the impact of angling on L. aeneus and L. kimberleyensis. The specific objectives of this study were to characterise the sectors utilising Lake Gariep, document catch, effort and total catch for the fishery as well as the locality specific biology of L. aeneus and L. kimberleyensis. The study was undertaken on Lake Gariep, South Africa's largest impoundment, situated on the Orange River system in central South Africa. Subsistence fishers were the dominant user group, constituting 60 % of the fishery, the remainder constituted recreational anglers. Angler catches were dominated by carp (Cyprinus carpio; 74 %), followed by mudfish (Labeo capensis; 13 %) and smallmouth yellowfish (8 %). Catches of largemouth yellowfish contributed < 0.5 % to the total catch. The relative abundance of species by weight differed by area (χ² test of independence: χ² = 182, df = 4, p ≤ 0.05). On any sampling day time fished was the best predictor for differences in probability of capture (PC) (Wald X²(1) = 7.169, p = 0.007). The probability of capturing L. aeneus differed significantly between month (Wald X²(5) = 20.690, p = 0.000) and region (Wald X²(3) = 46.755, p = 0.000). The single best predictor of differences in log abundance and non-zero CPUE was region (Factorial ANOVA p ≤ 0.05). Mean CPUE ranged from 0.21 ± 0.06 kg. man⁻¹.hr⁻¹ to 0.82 ± 0.11 kg. man⁻¹.hr⁻¹ in the OV region and 0.42 ± 0.10 kg. man⁻¹.hr⁻¹ to 1.17 ± 0.24 kg. man⁻¹.hr⁻¹ in the GD region. Angler effort was higher in OV than in GD and ranged from 17 ± 3 anglers/day to 45 ± 9 anglers/day and 6 ± 1 anglers/day to 41 ± 8 anglers/day, respectively. Total catch was higher in the GD 46.0 [95 % CI = 15:102.6] t. period⁻¹ than the OV region 40.0 [95 % CI = 13.9:89.6] t. period⁻¹. The total catch from the Lake Gariep fishery between March and December 2007 was estimated to be 86.0 [95 % CI = 40.4:154.8] t. period⁻¹. Age and growth was determined using whole otoliths. The growth of L. aeneus was best described by the von Bertalanffy growth model as Lt = 481.80 (1- e⁻°·²²⁽t⁺°·⁶¹⁾). Gonadal development for L. aeneus was seasonal, with the gonadosomatic index peaking in January, revealing a distinct spawning season. The length at 50 % maturity for female L. aeneus was attained at a fork length of 354.7 mm. Natural mortality (M) was estimated at 0.55 year⁻¹. The growth of L. kimberleyensis was described by the von Bertalanffy growth model as Lt = 763.22 (1- e⁻°·¹¹⁽t⁺°·⁶³⁾). Only 6 mature female and 15 mature male L. kimberleyensis were recorded during the study period. The smallest mature female was a 390 mm FL stage four female and the earliest recorded mature male was a 337 mm FL, ripe running male. Natural mortality (M) was estimated at 0.08 year⁻¹ for L. kimberleyensis. Per recruit analysis indicated that current fishing mortality reduces the L. aeneus spawner biomass by 7 %, which is considered negligible. Labeobarbus kimberleyensis forms an insignificant proportion of anglers catches and stock status is currently considered pristine.

The principal reason for the construction of Loskop Dam was to provide irrigation water to wheat farmers settling in the Olifants River valley in the 1920s. Agriculture has since developed in the area and today, the Loskop Irrigation Board supplies water to > 700 properties with an area of 25 600 ha farming cotton, wheat, citrus and grapes near the town of Groblersdal. Serious concerns were raised about deteriorating water quality when the crocodile population began to decline and the frequency of large fish kills increased from 2006. Crocodile (Crocodylus niloticus) and Mozambique tilapia (Oreochromis mossambicus) mortalities were linked to pansteatitis which is characterised by obesity and lipid peroxidation. Known impacts on water quality include eutrophication and acid mine drainage from coal mining with associated increases of soluble metals. The aims of this study were to: i) determine whether pansteatitis could be linked to any specific parameters in the water chemistry and limnology of Loskop Dam; ii) measure concentrations of aluminium, copper, iron, manganese, selenium and zinc in various tissues of O. mossambicus to determine whether bio-accumulation was occurring and could be related to pansteatitis; iii) assess the metazoan parasite communities of O. mossambicus to determine whether they are effective indicators of ecosystem health in Loskop Dam. Four established sampling sites were used at Loskop Dam and a reference site was located at neighbouring Kranspoort Dam. Surface water quality samples were collected monthly between July and December 2010 from each site and analysed for 27 constituents including nutrients, major ions, total metals, pH and dissolved oxygen using standard methods. Orthophosphate and total inorganic nitrogen results frequently categorised Loskop Dam as eutrophic and the transitional zone of the dam was characterised by very alkaline conditions resulting from algal blooms (median pH 9.67) which increase the solubility of metals like Al. A combination of active and passive biomonitoring techniques were used for fish collection. Fish gills, brain, muscle, liver and bone were analysed for Al, Fe, Mn, Zn, Cu and Se concentrations. The most striking result was an unanticipated significant deficiency in liver Cu concentrations of fish from Loskop Dam (mean 3.4 mg kg-1) compared to fish from Kranspoort Dam (mean 62 mg kg-1). Both endo- and ectoparasites were identified and enumerated on the fish and infection rates were calculated as mean intensity (I), mean abundance (A) and prevalence (P). Fish from Loskop Dam had extremely low infection rates and two fish had no parasites whatsoever. The ratio between monoxenous and heteroxenous parasites was calculated and was very high in fish from Loskop Dam compared to fish in Kranspoort Dam and Tompi Seleka, indicating a degraded aquatic ecosystem. While no single factor was outstanding as a possible cause of pansteatitis in this study, these findings provide a good foundation from which to formulate further research questions. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Paraclinical Sciences / unrestricted

The self-potential method responds to the electrokinetic phenomenon of streaming potential and has been applied in hydrogeologic and engineering investigations to aid in the evaluation of subsurface hydraulic conditions. Of specific interest is the application of the method to embankment dam seepage monitoring and detection. This demands a quantitative interpretation of seepage conditions from the geophysical data. To enable the study of variably saturated flow problems of complicated geometry, a three-dimensional finite volume algorithm is developed to evaluate the self-potential distribution resulting from subsurface fluid flow. The algorithm explicitly calculates the distribution of streaming current sources and solves for the self-potential given a model of hydraulic head and prescribed distributions of the streaming current cross-coupling conductivity and electrical resistivity. A new laboratory apparatus is developed to measure the streaming potential coupling coefficient and resistivity in unconsolidated soil samples. Measuring both of these parameters on the same sample under the same conditions enables us to properly characterize the streaming current cross-coupling conductivity coefficient. I present the results of a laboratory investigation to study the influence of soil and fluid parameters on the cross-coupling coefficient, and characterize this property for representative well-graded embankment soils. The streaming potential signals associated with preferential seepage through the core of a synthetic embankment dam model are studied using the forward modelling algorithm and measured electrical properties to assess the sensitivity of the self-potential method in detecting internal erosion. Maximum self-potential anomalies are shown to be linked to large localized hydraulic gradients that develop in response to piping, prior to any detectable increase in seepage flow through the dam. A linear inversion algorithm is developed to evaluate the three-dimensional distribution of hydraulic head from self-potential data, given a known distribution of the cross-coupling coefficient and electrical resistivity. The inverse problem is solved by minimizing an objective function, which consists of a data misfit that accounts for measurement error and a model objective function that incorporates a priori information. The algorithm is suitable for saturated flow problems or where the position of the phreatic surface is known. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Procedures for the selection, licensing and implementation of large scale energy projects must evolve with the escalating complexity of such projects and. the changing public value system. Government appeared unresponsive to rapidly changing conditions in the 1960s and 1970s. Consequently, approval of major hydroelectric development projects in British Columbia under the Water Act became increasingly more contentious. This led, in 1980, to the introduction of new procedures—the Energy Project Review Process (EPRP) — under the B.C. Utilities Commission Act. This study documents and evaluates the selection, licensing and implementation of the Revelstoke Hydroelectric Dam under the Water Act and assesses to what extent the current EPRP selection and licensing procedure overcame the shortcomings of the Revelstoke experience. The methodological approach used is that of a post-development analysis. The Revelstoke Project case study revealed that the Water Act only addressed project design, safety, and impacts, but not selection and justification. Project implementation proceeded under a conditional water licence. The two-part administrative framework, established under the licence and by B.C. Hydro, lacked integration and failed to provide effective management. A strong commitment to the preservation of environmental quality was lacking. The licensee's monitoring of construction practices in general and of compliance with environmental guidelines, a set of nonspecific commonly accepted construction activities, were inadequate. Governmental surveillance and enforcement were rendered unsatisfactory by staff shortages and a laissez faire attitude. The case study concluded with a post-development environmental analysis, which determined the effectiveness of the Environmental Impact Statement in predicting impacts to be only twenty-five percent. Evaluation of the EPRP and its application in the Site C Dam proposal demonstrated that it is a significant improvement over its predecessor. If applied efficiently and in its entirety, it would provide an adequate structure and procedural sequence for project selection and licensing. However, some of the inadequacies noted in the Revelstoke case study, such the lack of provisions for early public and government participation, an adequate data base, an administrative structure, and a post-development analysis, have not been or only partially corrected. To conclude, this thesis offers some recommendations to further improve this continually evolving process. / Arts, Faculty of / Geography, Department of / Graduate

The High Ross controversy was a problem in the management of an International river. An international river presents a special problem because the actions of a nation upstream may cause problems for a nation downstream or vice versa. A river is also a finite resource where uses for one purpose may exclude uses for other purposes. The use of a river for hydroelectric power, for example, may destroy fisheries. In the case of an international river, conflicting demands on water use may present serious problems if the nations riparian to the river fail to coordinate their planning with respect to the river. In this study, it is normatively assumed that the best system for insuring that the interests of all concerned will be heard is a democracy. In a democracy it is a principle that the decision system should respond to the preferences of its citizens. To do this it must first be able to perceive these preferences. A public hearing is one vehicle for accepting information concerning the preferences of citizens. The goal of this study is to assess certain public hearings which were held in reference to the raising of Ross Dam on the Skagit River in Washington State. The issue of whether to raise the dam has created an international controversy lasting for years and involving the energies of hundreds of persons on both sides of the border. The hearings of interest in this study are certain hearings of 1970 through 1972 held by the International Joint Commission, the Washington Ecological Commission, and the Seattle City Council. The approach taken in this thesis began with isolating two normative criteria among many which any democratic system must have: openness and efficiency. Openness is the ability of a system to perceive the preferences of its citizens. This means that there should be no arbitrary restrictions upon what the decision-makers should see. Efficiency means that the process should be simple and not limited to a select group with the most time, money, and expertise to participate. Having established these criteria, the next step was to isolate the location in the hearings system where one might expect to find evidence of openness and efficiency. To do this, a theoretical paradigm of a communication system was constructed from political communications theory. This paradigm contained the basic components of a simple communication system. Thus, it was found that any communication system will have messages (input), sources for those messages (input sources), and receptors for perceiving those messages (intake elements). In rational systems there will also be a memory process which selects relevant input from among the mass of intake (screening element). These elements were analyzed in order to assess the hearings investigated. To assemble the data necessary for assessment, a multi-method approach was used. Over four hundred articles in newspapers and periodicals were surveyed. The transcripts of the hearings and resulting reports were closely analyzed. Finally, selected participants who- had key roles in the hearings were interviewed. The information from these sources was used in tandem to examine particular aspects of the hearings process which were suggested by the communication model as relevant. The conclusions derived from this study were that with certain exceptions the procedures used in the hearings studied facilitated openness. Also, while the cost of using the hearings was very high, the participants with few exceptions felt that the expense was justified because the issue was crucial to their interests. However, the weaknesses that did exist in openness and efficiency merit attention and should be remedied to strengthen the system. The result of this strengthening would be a more responsive and democratic process for managing international rivers. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

Large dams are critical infrastructures whose failure could produce high economic and social consequences. For this reason, in recent years, the application of quantitative risk analysis to inform dam safety governance has risen significantly worldwide. This thesis is focused in how computed quantitative risk results can be useful to inform dam safety management. It proposes different methods and metrics to deal with the two key issues identified in this process: how risk results can be managed to prioritize potential investments and how uncertainty should be considered in quantitative risk models to inform decision making. Firstly, it is demonstrated that risk reduction indicators are a useful tool to obtain prioritization sequences of potential safety investments, especially in portfolios with a high number of dams. Different indicators for dam safety are assessed, analyzing their relation with equity and efficiency principles. Secondly, it is proposed to consider explicitly and independently natural and epistemic uncertainty in quantitative risk models for dams, following the recommendations developed by other industries. Specifically, a procedure is developed to separate both types of uncertainty in the fragility analysis for the sliding failure mode of gravity dams. Finally, both issues are combined to propose different metrics that analyze the effect of epistemic uncertainty in the prioritization of investments based on risk results. These metrics allow considering the convenience of conducting additional uncertainty reduction actions, like site tests, surveys or more detailed analysis. / Las grandes presas son infraestructuras críticas cuyo fallo puede producir importantes consecuencias económicas y sociales. Por este motivo, en los últimos años la aplicación de técnicas de análisis de riesgos para informar a la gobernanza de la seguridad de presas se ha extendido por todo el mundo. La presente tesis se centra en analizar cómo los resultados calculados de riesgo pueden ser útiles para la toma de decisiones en seguridad de presas. Para ello, se proponen diferentes métodos e indicadores que tratan los dos principales problemas identificados en este proceso: cómo gestionar los resultados de riesgo para priorizar potenciales inversiones en seguridad y cómo debe ser considerada la incertidumbre en los modelos de riesgo para orientar a la toma de decisiones. En primer lugar, se muestra como los indicadores de reducción de riesgo son una herramienta útil y eficaz para obtener secuencias de priorización de potenciales medidas de reducción de riesgo, especialmente en la gestión conjunta de grandes grupos de presas. Por ello, los diferentes indicadores para la gestión de la seguridad de presas son evaluados, analizando su relación con los principios de eficiencia y equidad. En segundo lugar, se propone considerar la incertidumbre epistémica y la incertidumbre natural de forma independiente dentro de los modelos de riesgo cuantitativos para presas, siguiendo las recomendaciones de otras industrias. En particular, se propone un procedimiento para separar ambos tipos de incertidumbre en el análisis del modo de fallo por deslizamiento en presas de gravedad. Finalmente, ambos puntos se combinan para proponer diferentes índices que analicen la influencia de la incertidumbre epistémica sobre las secuencias de priorización obtenidas mediante indicadores de reducción de riesgo, y por lo tanto, sobre la toma de decisiones. De esta forma, estos índices permiten analizar la necesidad de realizar acciones adicionales para reducir la incertidumbre epistémica, como ensayos, sondeos o estudios detallados. / Les grans preses son infraestructures crítiques que si fallen poden produir importants conseqüències econòmiques i socials. Per aquest motiu, en el últims anys la aplicació de tècniques d'anàlisis de rics per a informar a la governança de seguretat de preses s'ha estès per tot el món. Aquesta tesi es centra en analitzar com els resultats calculats de risc poden ser útils per a prendre decisions en seguretat de preses. Per a això, es proposen diferents mètodes i indicadors que tracten el dos principals problemes identificats en aquest procés: com gestionar els resultats de risc per a prioritzar potencials inversions en seguretat i com el models de risc han de considerar la incertesa per a orientar a la presa de decisions. En primer lloc, es mostra com el indicadors de reducció de riscs son una ferramenta útil i eficaç per a obtindré seqüències de priorització de potencials mesures de reducció de risc, especialment en la gestió conjunta de grans grups de preses. Per això, els diferents indicadors per a la gestió de la seguretat de preses son avaluats, analitzant la seua relació amb els principis d'eficiència i equitat. En segon lloc, es proposa considerar la incertesa natural i la incertesa epistèmica de forma independent dintre del models quantitatius de risc per a preses, seguint les recomanacions d'altres industries. En particular, es proposa un procediment per a separar el dos tipus d'incertesa en el anàlisis del fall per lliscament en preses de gravetat. Finalment, el dos punts es combinen per a proposar índexs que analitzen la influència de la incertesa epistèmica sobre les seqüencies de priorització de mesures obtingudes amb els indicadors de reducció de risc, y per tant, sobre la presa de decisions. D'aquesta forma, aquests índexs permeten analitzar la necessitat de realitzar acciones per a reduir la incertesa, como assajos, sondejos geotècnics o estudis de detall. / Morales Torres, A. (2017). Evaluation of the impact of risk reduction indicators and epistemic uncertainty in dam safety governance [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/79739 / TESIS