Dissertations / Theses on the topic 'Surface water quantification'

Geosmin is a strong musty-flavored organic compound that is responsible for many taste-and-odor events in surface drinking water sources like lakes and reservoirs. The taste threshold of geosmin for humans is lower than 10 ng/L. Traditional treatment methods will not remove geosmin to this level. Additional water treatment methods must be implemented to successfully remove the geosmin and its associated flavor and odor from drinking water. Furthermore, geosmin is produced by cyanobacteria somewhat sporadically, so it is difficult to predict when taste-and-odor events are going to occur. The difficulty involved with predicting geosmin events has led most water treatment facilities to adopt reactive approaches towards geosmin treatment; these facilities typically treat for geosmin in response to complaints of an earthy off-flavor in the drinking water. This reactive approach causes issues with consumer confidence, as the flavor of the water is one of the only metrics a consumer has for judging the safety of his or her water. To enable proactive treatment of geosmin from water, more sensitive methods for geosmin detection or taste-and-odor event prediction must be developed.This study investigates the use of quantitative Polymerase Chain Reaction (qPCR) for the early detection of geosmin-producing cyanobacteria. qPCR can detect geosmin-producing cyanobacteria via their DNA. I developed a qPCR assay for this study that is capable of sensitively detecting multiple strains of the geosmin-producing Nostoc genus. The developed assay showed high sensitivity, demonstrating the possibility for its use in detecting low concentrations of geosmin-producing cyanobacteria before detectible levels of geosmin have been produced and released into the water. Through further sequencing of more geosmin-producing genera and species, the methodology outlined in this research could be applied to develop the tools necessary to predict taste-and-odor events caused by geosmin-producing cyanobacteria.

Les retenues collinaires sont des aménagements hydrauliques largement rencontrés en Afrique du Nord, et plus généralement dans les zones arides et semi-arides de la planète. Ils visent à la fois la conservation en eau dans les bassins versants amont et la rétention des matériaux issus de l'érosion afin d'éviter l'envasement des grands barrages en aval. L'implantation et la gestion de l'eau mobilisée par les retenues collinaires doit s'appuyer sur une connaissance de leur fonctionnement hydrologique. Or ce fonctionnement est encore peu connu, en particulier les processus et l'intensité des flux des échanges retenue-souterrain, constituent une question très ouverte. L'objectif de ce travail est de quantifier et d'analyser le fonctionnement des échanges retenue-souterrain sur un bassin versant agricole. L'étude a été menée sur la retenue collinaire du bassin versant expérimental de Kamech, appartenant à l'ORE OMERE. Dans la première partie de ce travail, une approche de bilan hydrologique a été développée et a permis de montrer que les échanges retenue-souterrain sont dominés par l'infiltration, qui représente environ 79 % des pertes à la retenue collinaire et dépasse largement les pertes par évaporation qui ne représente que 21 %.En revanche, l'analyse croisée des dynamiques hydrologiques dans la retenue et dans la nappe au voisinage de la retenue a mis en évidence des échanges qui se produisent dans les deux sens : des échanges dominés par un flux d'infiltration avec la nappe au pied du barrage, par contre, les échanges avec la nappe latérale des versants se produisent dans les deux sens mais restent très fugaces. Les résultats préliminaires de l'approche de modélisation développé dans ce travail a permis de souligner la complexité des échanges retenue-souterrain et montre que la relation entre la hauteur d'eau dans la retenue et le flux d'infiltration n'est pas univoque et présente des comportements différents entre la phase de montée et la phase de descente du niveau d'eau dans la retenue
Hill reservoirs are hydraulic infrastructures widely used in North Africa, generally in arid and semi arid zones of the planet. These infrastructures are used for both water conservation in the catchment scale and to reduce siltation of downstream dams. The implementation and the management of water resources mobilized in this infrastructure must be based on knowledge of their hydrological functioning. However, the hydrological functioning of this system is not very known, especially the water flux exchange processes and intensity between the reservoir and the subsurface is still an open question.The main purpose of this study is to quantify and analyse the hydrological functioning of the reservoir-subsurface exchange processes for an agricultural catchment. This study was conducted on the hill reservoir of the experimental observation site of Kamech belonging to the OMERE observatory. In the first part of this study, we develop a water balance approach to estimate reservoir-subsurface exchange flux. The results of this approach shows that reservoir-subsurface exchange flux is dominated by infiltration that represent about 79% of the water outflow, and largely exceeds the water loss by evaporation that represents only 21 % of the total water outflow. However, the cross-analysis of the hydrological dynamics of the hill reservoir and the aquifer in the vicinity of the reservoir revealed that infiltration can occur in both directions: reservoir-subsurface exchange dominated by infiltration with the aquifer located in the foot of the dam, however the water exchange with the lateral aquifer of the hill reservoir can occur in both directions but remain very fleeting. The preliminary results of the modeling approach developed in this work has highlighted the complexity of reservoir-subsurface exchange flux. In fact, the relationship between water level in the hill reservoir and the infiltration flux is not unique and can present different behavior between the rise and decrease phase of the water level in the hill reservoir

Die Arbeit besteht aus mehreren Studien zur Quantifizierung des Grundwasserstroms in Seen (Exfiltration; engl.: lacustrine groundwater discharge, LGD) und damit verbundener Nährstoffeinträge. In zwei einleitenden Kapiteln dieser Arbeit werden eine Gründe für die Vernachlässigung der Grundwasserexfiltration (LGD) in Seen und der daran gekoppelten Nährstoffeinträge identifiziert. Diese Literaturstudien fassen den aktuellen Kenntnisstand zum Einfluss des Grundwassers auf die Hydrologie von Seen und ihre Nährstoffhaushalte zusammen. Den Kern der vorliegenden Arbeit bilden zwei empirische Studien, die sich mit der Quantifizierung der grundwasserbürtigen Phosphor (P)-Fracht in den Arendsee in Deutschland befassen. Das Gesamtvolumen des Grundwasserzustroms wird basierend auf der Grundwasserneubildung im Einzugsgebiet des Sees ermittelt. Lokale Muster der Grundwasserexfiltration werden anhand von Temperaturtiefenprofilen des Seesediments bestimmt. Eine Kombination der Ergebnisse ermöglicht es, die quantitativen Daten mit lokalen Informationen zu unterstützen. Die Untersuchung der Grundwasserqualität zeigt, dass die P-Konzentrationen im Grundwasser im besiedelten Bereich teilweise stark erhöht sind. Als Konsequenz daraus haben die grundwasserbürtigen P-Frachten einen Anteil von mehr als 50% an der gesamten externen P-Last des Arendsees. Das Grundwasser ist damit eine maßgebliche Ursache für die Eutrophierung des Gewässers. Drei weitere Studien widmen sich der Entwicklung und Optimierung von Ansätzen zur qualitativen und quantitativen Bestimmung der Grundwasserexfiltration in Seen. Die kritische Auseinandersetzung mit den Ergebnissen der Studien zeigt die Notwendigkeit weiterer Forschung zur Verbesserung und Standardisierung der Methoden zur Bestimmung von LGD und damit verbundenen Stofftransporten auf. Der Fall des Arendsees sollte alle, Wissenschaftler und Praktiker, dazu motivieren, das Grundwasser als relevante Eutrophierungsquelle in Betracht zu ziehen.
The present work is a collection of studies on lacustrine groundwater discharge (LGD) and groundwater-borne phosphorus (P) loads. For a number of reasons, groundwater exfiltration (i.e., LGD) is often not considered in water and nutrient budgets of lakes. This is also and especially true for P which was often regarded to be immobile in groundwater until recently. Two chapters review the scientific literature regarding the impacts of groundwater on hydrology and nutrient budgets of lakes, respectively. They present mechanisms and processes of LGD as well as techniques and methods to measure LGD and related nutrient transports. Moreover, numbers of LGD volumes and loads reported in literature are presented. The core of the present work is represented by two case studies dealing with the quantification of P loads from LGD to a lake in Germany. A combination of different methods is applied to overcome the problem of quantitative large scale LGD determination without losing local spatial information. P concentrations in groundwater and LGD are investigated by detailed spatial water sampling. The results reveal that P is actually present in concentrations far above natural background concentrations in the urban groundwater. LGD-derived P loads account for more than 50% of the overall external P loads to the lake and by that contribute significantly to lake eutrophication. Three further studies are devoted to the development and improvement of approaches to determine LGD. Critical reviews of the above mentioned studies reveal the need for further research in order to standardize and improve methods for LGD and mass load determination. It is found that the appropriate method for LGD determination depends on the spatial scale of interest. The identification of P introduced by LGD as a main driver of lake eutrophication is an important finding which should encourage scientists, policy makers, and lake managers to consider groundwater as a relevant P source for lakes.

Compte tenu de l’évolution démographique et climatique planétaire, la gestion de la ressource en eau constitue un défi majeur auquel la communauté internationale devra faire face au cours du XXIème siècle. A cet effet, l'identification de la continuité hydrique entre les eaux de surface et les eaux souterraines permet l'introduction de la notion de gestion intégrée de la ressource. L'application de ce principe de gestion au bassin de la Seine, à travers l'estimation des échanges nappe-rivière, est rendue possible par la mise en pratique du concept d'interface nappe-rivière emboitées au sein de travaux de modélisation. Pour cela une procédure de modélisation multi-échelles peut être mise en place. Elle vise à intégrer des informations locales au sein de modélisation à une échelle supérieure. Dans ce mémoire, une procédure de modélisation multi-échelles est mise en œuvre. Ce protocole de modélisation est initié par une estimation des flux d'eau régionaux au sein de l'hydrosystème Seine. La cohérence globale de ces flux est garantie par le développement d'une méthodologie de calibration de modèles couplés en deux étapes. Ensuite les informations locales, que sont les hétérogénéités de la plaine alluviale de la Bassée et de la représentation des interfaces nappe-rivière du réseau secondaire, sont intégrées au modèle régional par une procédure de modélisation emboitée et de changement d'échelle des paramètres hydrauliques. La mise en place de cette procédure a finalement permis l'estimation fine des échanges nappe-rivière sur la quasi-totalité (83%) du réseau hydrographique naturel du bassin de la Seine et ainsi de répondre aux recommandations de gestion intégrée de la ressource faites par la directive cadre sur l'eau
Given the current climate and anthropogenic evolutions, water management becomes one of the greatest challenges of the 21st Century. For that purpose, by identifying hydraulic continuity between surface and subsurface water, the concept of integrated water management can be introduced. In this work this management concept is applied on the Seine basin by quantizing hydrological processes occuring at the nested stream-aquifer interface. The implementatin of the nested interface concept can bedone through multi-scale modeling. This modelling procedure, aimed at embody the local characteristics of the interfaces (such as structural or hydrodynamic heterogeneities) in large scale models. A multi-scale modelling procedures is applied to the regional Seine basin model (70000 km²) in order, to study the hydrodynamic behaviour of the Bassée alluvial plain, and to quantify the stream-aquifer exchanged fluxes at the basin scale. The modelling protocol is initiated with regionals fluxes estimation over Seine hydrosystem. Regional fluxes consistency are assured by a two-step calibration procedure of fully coupled models. Then, the local characteristics of the Bassée alluvial plain, are implemented in the regional model by nested modelling methodology associated with upscaling procedure of hydraulics properties. Finally, the multi-scale modelling procedure lead to quantify distributed stream-aquifer exchanged water fluxes over 83% of the natural river network of the Seine basin, and thus, achieve to answer the integrated water resources management recommandations of the water framework directive

Les échanges entre les rivières et les nappes d’eau souterraine jouent un rôle essentiel dans le maintien des écosystèmes aquatiques. Or, leur caractérisation demeure difficile du fait de leur forte variabilité dans l’espace et dans le temps. Dans ce contexte, l’objectif de ce travail de thèse est de développer des méthodes actives de mesures distribuées de température pour quantifier la dynamique des interactions nappe/rivière. Après avoir établi une nouvelle approche pour évaluer la résolution spatiale des mesures de température, nous avons validé deux nouvelles méthodes d’interprétation permettant d’estimer de manière distribuée les flux d’eau et la conductivité thermique du milieu poreux. Les travaux, associant modélisations numériques et mesures expérimentales en laboratoire, montrent que les méthodes d’interprétation développées permettent d’estimer avec une excellente précision les écoulements et que la gamme de flux pouvant être investiguée est particulièrement large. Pour tester cette approche prometteuse, des expériences actives ont ensuite été réalisées sur le terrain dans deux environnements différents : d’abord dans un petit cours d’eau d’ordre 1 de tête de bassin versant, puis dans un fleuve s’écoulant le long d’une plaine alluviale. Ces applications ont démontré le fort potentiel des méthodes actives pour quantifier les écoulements à l’interface nappe/rivière et décrire leur variabilité spatiale et temporelle. La comparaison des résultats obtenus sur les deux sites a permis finalement de discuter la faisabilité, les apports mais aussi les limites de la méthode dans différents contextes hydrologiques
Groundwater/surface water interactions play a fundamental role in the functioning of aquatic ecosystems. However, their quantification is challenging because exchange processes vary both in time and space. Here, we propose an active distributed heat transport experiment in order to quantify the spatial and temporal variability of groundwater/surface water interactions. As a first step, we proposed a new approach to evaluate the spatial resolution of temperature measurements. Then, two interpretation methods of active-DTS experiments were developed and fully validated to estimate the distribution of porous media thermal conductivity and the groundwater fluxes in sediments. Based on numerical simulations and sandbox experiments, results demonstrated the potentiality of these methods for quantifying distributed groundwater fluxes with high accuracy. The large range of groundwater fluxes that can be investigated with the method makes specially promising the application of active experiments for many subsurface applications. Secondly, we conducted heat transport experiments within the streambed sediments of two different streams: in a first-order stream, then in a large flow-system located along an alluvial plain. These applications demonstrated the relevance of using active experiments to characterize the spatial complexity of stream exchanges. Finally, the comparison of results obtained for each experimental site allowed discussing the capabilities and limitations of using active-DTS field experiments to characterize groundwater/surface water interactions in different hydrological contexts

碩士
國立中央大學
土木工程學系
105
Conventional measures to monitor terrestrial water resources are the deploy of water gauges and in situ well. However, these methods are not only expensive and time-consuming, but also require lots of manpower and infrastructure setups. Therefore, using satellite observations to build a water resource monitoring network becomes an attracting alternative. Ranking as the 10th highest population density in the world, Bangladesh is suffering from multiple freshwater issues. Although the monsoon heading from the Indian Ocean brought lots of rainfall that even induce serious floods every year, it is not practicable for Bangladesh to store surface water due to its flat terrain. Meanwhile, the over-pumping of groundwater has induced extensive land subsidence in many administrative divisions. Therefore, Bangladesh needs a monitoring network that can provide large-scale and continuous data to manage their water resources. This research proposes a method to quantify surface water volume and further estimate the sub-surface water (include soil moisture and groundwater) trend. The study case focuses on Sylhet Plain which has the highest annual precipitation in Bangladesh. We first use the modified normalized difference water index to extract water area from Terra/MODIS MOD09A1 product and Landsat-5/-7/-8 Thematic Mapper (TM)/Enhanced TM plus (ETM+)/Operational Land Imager (OLI) imageries. Then we accumulate a sequence of images to create flood chance model for the recovery of cloud-covered surface. This approach extends the time series of WA with an overall accuracy of 70–80% in rainy season and 40–50% in dry season. This model can be further used to refine Shuttle Radar Topography Mission (SRTM), which has few meters uncertainty. Next, we simulate the flood extent using the modified SRTM and obtain and the overall accuracy of flood extent increases 19% compared to original data. By combining recovered WA and reconstructed DEM, the surface water volume (WV) is quantified and the signals of two extreme flood events in 2004 and 2007 are well observed in the estimated WV curve. The shifting days between estimated WV and GRACE equivalent water heights (EWHs) are 4 days in Sylhet Plain and 15 days in Brahmaputra River. The correlation coefficient and RMS of the EWH difference are 91.7% / 0.10 m in Sylhet plain and 95.48% / 0.12 m in Brahmaputra River. Finally, we subtract surface water from GRACE EWH and the result shows a decreasing trend of sub-surface water at 0.5 cm yr-1 in Sylhet Plain and decreasing trend at 1.7 cm cm yr-1 in Brahmaputra River, which agree with previous studies.

Thesis (M. Tech. - Dept. of Chemistry, Faculty of Applied and Computer Sciences) -- Vaal University of Technology, 2010
The increased production and application of pesticides for agricultural and non-agricultural purposes has caused the pollution of air, soil, ground and surface water. This has a negative impact on the environment as well as human health due to direct exposure or through residues in food and drinking water. The continuous monitoring of pesticides residues in environmental samples has great importance and demands high efficiency, unique selectivity and high sensitivity techniques. Gas chromatography and high performance liquid chromatography have been established for years as the techniques for the analysis of pesticides residues. The dissertation deals with the qualitative and quantitative determination of selected pesticides in the Southern Gauteng region using Liquid- liquid extraction solid-phase extraction, high performance liquid chromatography, gas chromatography equipped with electron capture detector and gas chromatography mass spectrometry. Liquid-liquid extraction and solid-phase extraction using dichloromethane, hexane and ethyl acetate as the extracting solvent were optimized and evaluated for the determination of pesticides in surface water in the Southern Gauteng region. From the developed method the techniques were applied to water samples taken from different rivers selected namely: Zuikerbosch, Rand Water barrage and Kliprivier for sampling. Dichloromethane was used as a solvent in this study since a recovery test was done between dichloromethane, Ethyl acetate and n-hexane. The percentage recovery test for 4,4-DDT, 4,4-DDE, 2,4-DDD and Endosulfan 1 & 2 ranged from 89.9% -97.3% for dichloromethane, 87.3%-96.8% for hexane 88.4%-97.1% for ethyl acetate. The extracts obtained were subjected to column chromatography for clean up. Thereafter 1µl of the cleaned extracts were injected into the Gas chromatography equipped with an electron capture detector. Organochlorines 4,4-DDT and its metabolites, Organophosphate Chlorypyriphos and carbamates were detected using Gas chromatography electron capture, Gas chromatography mass spectrometry and high performance liquid chromatography.

Le présent projet vise à documenter la nécessité d’augmenter notre connaissance de la présence des contaminants organiques tels que les médicaments dans l’environnement et d’évaluer leur devenir environnemental. On a étudié la présence de composés pharmaceutiques dans différents échantillons d'eau. On a focalisé nos efforts spécialement sur les échantillons d'eau de l'usine d'épuration de la Ville de Montréal et ses effluents, les eaux de surface avoisinantes et l’eau du robinet dans la région de Montréal. Pour ce faire, on a tout d’abord développé deux méthodes analytiques automatisées basées sur la chromatographie liquide avec extraction en phase solide (SPE) couplée à la chromatographie liquide couplée à la spectrométrie de masse en tandem (LC-MS/MS). On a également étudié les performances des trois techniques d'ionisation à pression atmosphérique (API), pour ensuite les utiliser dans la méthode analytique développée. On a démontré que l'ionisation par électronébulisation (ESI) est une méthode d'ionisation plus efficace pour l'analyse des contaminants pharmaceutiques dans des échantillons de matrices très complexes comme les eaux usées. Une première méthode analytique SPE couplée à la LC-MS/MS a été développée et validée pour l'étude des échantillons complexes provenant de l'usine d'épuration de la Ville de Montréal et des eaux de surface près de l'usine. Cinq médicaments de prescription ont été étudiés: le bézafibrate (un régulateur de lipides), le cyclophosphamide et le méthotrexate (deux agents anticancéreux), l'orlistat (un agent anti-obésité) et l’énalapril (utilisé dans le traitement de l'hypertension). La plupart de ces drogues sont excrétées par le corps humain et rejetées dans les eaux usées domestiques en faisant par la suite leur chemin vers les usines municipales de traitement des eaux usées. On a pu démontrer qu'il y a un faible taux d’élimination à l'usine d'épuration pour le bézafibrate et l'énalapril. Ces deux composés ont aussi été détectés dans les eaux de surface sur un site à proximité immédiate de la décharge de l’effluent de la station d'épuration. i En observant la nécessité de l'amélioration des limites de détection de la première méthode analytique, une deuxième méthode a été développée. Pour la deuxième méthode, un total de 14 contaminants organiques, incluant trois agents anti-infectieux (clarithromycin, sulfaméthoxazole et triméthoprime), un anticonvulsant (carbamazépine) et son produit de dégradation (10,11-dihydrocarbamazépine), l'agent antihypertensif (enalapril), deux antinéoplastiques utilisés en chimiothérapie (cyclophosphamide et méthotrexate), des herbicides (atrazine, cyanazine, et simazine) et deux produits de transformation de l’atrazine (deséthylatrazine et déisopropylatrazine) ainsi qu’un agent antiseptique (triclocarban). Ces produits ont été quantifiés dans les eaux de surface ainsi que dans l’eau du robinet. L'amélioration des limites de détection pour cette méthode a été possible grâce à la charge d'un volume d'échantillon supérieur à celui utilisé dans la première méthode (10 mL vs 1 mL). D'autres techniques de confirmation, telles que les spectres des ions produits utilisant une pente d’énergie de collision inverse dans un spectromètre de masse à triple quadripôle et la mesure des masses exactes par spectrométrie de masse à temps d’envol, ont été explorées. L'utilisation d'un analyseur de masse à temps d’envol a permis la confirmation de 6 des 14 analytes. Finalement, étant donné leur haute toxicité et pour évaluer leur persistance et leur transformation au niveau du traitement des eaux potables, la cinétique d'oxydation du cyclophosphamide et de méthotrexate avec l'ozone moléculaire et des radicaux OH a été étudiée. Les constantes de dégradation avec l'ozone moléculaire ont été calculées et la qualité de l'eau après traitement a pu être évaluée. Le rendement du processus d'ozonation a été amélioré pour la cyclophosphamide dans les eaux naturelles, en raison de la combinaison de réactions directes et indirectes. Cette étude a montré que l'ozone est très efficace pour oxyder le méthotrexate mais que le cyclophosphamide serait trop lent à s’oxyder pour un traitement efficace aux conditions usuelles de traitement de l’eau potable.
This project aims to document the need to increase our knowledge of organic contaminants such as pharmaceuticals in the environment and to assess their environmental fate. We studied the presence of pharmaceutical compounds in different water samples. We studied their presence in wastewater samples from the treatment plant of the City of Montreal, effluents, surface and tap water. To do this we developed two analytical methods based on solid phase extraction (SPE) coupled to liquid chromatography -tandem mass spectrometry (LC-MS/MS). . The performance of three atmospheric pressure ionization (API) techniques was also studied for their subsequent use in the developed method. It was demonstrated that electrospray ionization (ESI) is a more effective ionization method for the analysis of pharmaceutical contaminants in samples as complex as wastewaters. A first analytical LC-MS/MS method, was developed and validated for the investigation of samples from the wastewater treatment plant and surface waters near the plant of Montreal. Five prescription drugs were studied: bezafibrate (lipid regulator), cyclophosphamide, and methotrexate (two anticancer agents), orlistat (an anti-obesity agent) and enalapril used in the treatment of hypertension. Most of these drugs are excreted by the human body in high percentages and released into domestic wastewaters, making their way to the municipal wastewater treatment plants. It was demonstrated that there is a low rate of elimination at the wastewater treatment plant for bezafibrate and enalapril. These two compounds were also detected in surface waters on a site close to the discharge of the treatment plant effluents. For this first analytical method we observed the necessity of improvement of the detection limits of the method. A second method was then developed to improve the detection limits and to study a total of 14 organic contaminants, including three antiinfective agents (clarithromycin, sulfamethoxazole and trimethoprim), an anticonvulsant (carbamazepine) and its degradation product 10,11-dihydrocarbamazepine, the iii antihypertensive agent (enalapril), two antineoplastic (methotrexate and cyclophosphamide), herbicides (atrazine, cyanazine, and simazine) and two transformation products of atrazine (desethylatrazine and déisopropylatrazine) and an antiseptic agent (triclocarban). These products were quantified in surface water and tap water. The improvement of the detection limits of this method was possible due to the loading of a greater sample volume than that used in the first method (10 mL vs 1 mL). Other confirmation techniques, such as the data-dependent reverse energy ramp scan on a triple quadrupole and accurate mass measurements on a time-of-flight mass spectrometer were explored. Using time-of-flight mass spectrometer determinations allowed the confirmation of six of the 14 analytes. Finally, due to their toxic properties, the oxidation kinetics of cyclophosphamide and methotrexate with molecular ozone and OH radicals was studied in bench scale. The degradation constants with molecular ozone were calculated and the water quality after treatment was assessed. The overall process performance was improved for cyclophosphamide in natural waters, due to the combination of direct and indirect reactions. The study showed that ozone is very effective for the oxidation of methotrexate, but cyclophosphamide is too slowly oxidized for an effective drinking water treatment under usual conditions.

Secondary dryland salinity in Australia has been a major environmental concern for a number of decades, yet aspects remain controversial. These include the processes which induce salinised soils, the environmental impacts of salinity, and the way in which it is mapped and managed. Dryland salinity has been almost universally attributed to rising saline groundwater caused by excess water accumulation in the landscape following European settlement and tree clearing. However, there is a body of evidence that instead suggests increased soil salinisation in SE Australia is attributable to localized surface water problems associated with soil and vegetation degradation. The ‘Rising Groundwater Model’ has been widely accepted as the paradigm for understanding, mapping and monitoring dryland salinity. However, little quantitative research has been undertaken to understand the mechanisms and processes that cause secondary dryland salinity in the uplands of south eastern Australia. Further, there is little research that demonstrates adverse impacts of secondary salinity on terrestrial endemic biota even though it is listed as a threatening process to biodiversity. This research tested the applicability of an alternative ‘Surface Water Model’ to explain outbreaks of salinity or soil surface degradation in this region. This research investigated the effects of the joint phenomenon of soil and vegetation degradation and elevated salinity levels on soil biotic and abiotic parameters. Field research was conducted at ten box/gum grassy woodland sites in the agricultural zone of the Southern Tablelands of NSW. A holistic suite of metrics, including soil physical, chemical, hydrological and biological attributes, were assessed in the field and laboratory; geophysical surveys (EM31/EM38) and various fauna and flora surveys were performed. Results indicated that degraded soil surfaces were generally small in area and localized. These surfaces had highly variable soil EC levels (often very low), and were associated with in situ synergistic factors related to in situ soil and vegetation degradation. Some surfaces had accumulated NaCl, but many also had other, both toxic and low cation and anion levels particularly reduced levels of Ca, Fe, N, SOM and SOC. Extreme pH levels and other soil physical, chemical and biological impacts were also common. It is concluded that elevated soil salinity levels are a symptom of soil and vegetation degradation, not the cause. It was found that the predominant water movement in these landscapes occurred as overland runoff and surficial lateral interflow above the clay-dominant B horizon. There was no biological, pedological, geophysical or hydrological evidence of groundwater being a major factor for elevated soil surface salinity levels. Evidence suggests that these degraded ecosystems are relatively stable but urgently require nutrient/SOM input. Many endemic fauna and flora species flourish at highly degraded and salinised sites; tolerating elevated and fluctuating salinity levels, at all life cycle stages, which may effectively increase the gamma biodiversity in these grassy woodlands. No evidence was found to suggest that biodiversity is suffering from rising saline groundwater or elevated soil salinity levels per se, or that elevated salinity levels favour exotic species. It is therefore problematical to directly link soil salinity per se with ecological stress, as many other synergistic factors are involved and are more significant for degraded soils. Management decisions based on reducing the soil surface evaporation potential on site is the most coherent approach. Management activities should focus on stock grazing exclusion, soil amelioration and revegetation activities using endemic species, rather than focusing on excess deep landscape water management with hybrids and exotic plants. The present use of AEM for mapping dryland salinity in upland environments is therefore questionable.

The nuclear industry has long relied upon bounding parametric analyses in predicting the safety margins of reactor designs undergoing design-basis accidents. These methods have been known to return highly-conservative results, limiting the operating conditions of the reactor. The Best-Estimate Plus Uncertainty (BEPU) method using a modernized version of the Code-Scaling, Applicability, and Uncertainty (CSAU) methodology has been applied to more accurately predict the safety margins of the Oregon State University Advanced Plant Experiment (APEX) facility experiencing a Loss-of-Feedwater Accident (LOFA). The statistical advantages of the Bayesian paradigm of probability was utilized to incorporate prior knowledge when determining the analysis required to justify the safety margins. RELAP5 Mod 3.3 was used to accurately predict the thermal-hydraulics of a primary Feed-and-Bleed response to the accident using assumptions to accompany the lumped-parameter calculation approach. A novel coupling of thermal-hydraulic and statistical software was accomplished using the Symbolic Nuclear Analysis Package (SNAP). Uncertainty in Peak Cladding Temperature (PCT) was calculated at the 95/95 probability/confidence levels under a series of four separate sensitivity studies.
Graduation date: 2013