Dissertations / Theses on the topic 'Indicators of hydrologic alteration'

Mestrado em Gestão e Conservação de Recursos Naturais - Instituto Superior de Agronomia
This study aimed to improve our understanding of the ecohydrological characteristics of environmental and modified flows in Portuguese rivers considered Heavily Modified Water Bodies (HMWB), using the Indicators of Hydrologic Alteration (IAH) method. For a given set of "heavily modified river sections", this study did the characterization and analysis of present flow regimes observed, natural flow regimes, and ecological flow requirements simulated by the method of INAG, DSP (2002). Based on Indicators of Hydrologic Change, the determination of the deviations from natural regimes was performed for the present hydrological regimes: both modified and ecological. The analysis of indicators of hydrologic alteration, based on ecohydrologic assumptions that guide the definition of environmental flow regimes, allowed to develop proposals for environment mitigation, whose effectiveness should be evaluated in the context of monitoring the ecological quality of HMWB sections in order to achieve the environmental objectives set out in national and European legislation on water resources the Water Frame Directive WFD (Directive 2000/60/EC) transposed to the Portuguese legislation by the Water Law - Law n.º 58/2005, 29 December 2005

Abstract Hydrologic Alteration and Sedimentation in the Upper Henry’s Fork Watershed Amelie Jeanne Charnaux The Henry’s Fork of the Snake River is venerated by the global recreational community as one of the finest trout fishing streams on the planet. Furthermore, this remarkable waterway flows within the bounds of one of the most important ecological corridors in the equally world-renowned Greater Yellowstone Ecosystem. While the recreational and biological features of this corner of Idaho may capture the interest of the broader public, the waterway is equally significant to the livelihoods of local interests, such as the ranching and farming communities. With the stakes running high for all interest groups, a case study of the Henry’s Fork watershed provides a valuable baseline narrative for understanding decision-making related to water resources not only in Idaho, but also in other Western states. Environmental impacts of the Henry’s Lake Dam and management of the stream below the structure were evaluated by literature review and GIS mapping, with research emphasis placed on the ecological integrity and fisheries of the Upper Henry’s Fork Subbasin. The literature review focused on natural processes in stream ecosystems and anthropogenic impacts, with the goal of providing information for the development of management policies that minimize the negative impacts of current flow management and land use. Literature sources overwhelmingly agree that the alteration of natural hydrologic regimes is the most serious and continuing threat to the sustainability of river ecosystems. In recent decades, downstream recreational fishing declined on the upper Henry’s Fork due to increased sedimentation, inciting investigation as to the source. Three major anthropogenic factors targeting one section of the river, the Henry’s Lake Outlet, set the stage for excess sedimentation. First, the Henry’s Lake Dam was constructed in 1923, impacting the Outlet’s hydrology through changes in the timing, magnitude, and frequency of low and high flows. Second, an artificial stream channel was constructed in the 1920s to bypass the meandering Outlet in order to increase conveyance capacity of irrigation water from Henry’s Lake to downstream water users. Third, long-term livestock grazing along this section of river dramatically reduced riparian and upland vegetation, triggering the loss of stream-bank stability and increasing erosion and sedimentation. These management practices have resulted in significant loss of biodiversity in the stream ecosystem and an increased rate of erosion in the Outlet. The Henry’s Lake Outlet restoration project, led by the Henry’s Fork Foundation, provides the opportunity to predict potential effects of large-scale restoration in the Henry’s Fork watershed. The project seeks to reduce sediment delivery downstream from the Outlet by rerouting flow from the straightened channel into the historic channel. The project tests the hypothesis that, by restoring the meandering stream channel, and thereby adding a half-mile to the Outlet, bank erosion and channel instability will decrease, the interaction between stream and riparian habitats will improve, and overall ecosystem health will benefit. In spite of the proactive intentions of the project, it will not change the current management of stream flow. In order to restore the Henry’s Lake Outlet to a state of dynamic equilibrium in terms of erosion and sediment load, the flows from Henry’s Lake Dam must more closely reflect the natural hydrologic regime. However, the ability to implement full restoration of the Outlet is complicated by the conflict between the requirements for ecosystem health and economic and socio-political pressures, a story common to many water systems throughout the West. Ultimately, it is hoped that this research may be integrated into policy and conservation strategy to mitigate streambank erosion and sedimentation in the Henry’s Fork Subbasin.

Sabe-se que a formação de reservatórios altera a qualidade e a quantidade da água de montante e jusante e que a direção e a magnitude das alterações dependem de suas características construtivas, operacionais, morfométricas, bem como do regime hidrológico e climático da região. Porém, a maior parte deste conhecimento foi fundamentada em pesquisas de reservatórios com grande capacidade de regularização, que fazem parte da realidade do Pantanal, uma região que vem sendo impactada por um número cada vez maior de reservatórios com pequena capacidade de regularização, levantando questionamentos sobre seus possíveis efeitos no funcionamento da planície de inundação. Sendo assim, este trabalho procurou (i) identificar qual o fator chave determinante no processo de estratificação e mistura vertical do reservatório e se este pode influenciar na qualidade da água; (ii) avaliar os efeitos da formação e operação do reservatório na alteração da qualidade da água de montante e jusante e (iii) avaliar os efeitos da operação do reservatório na alteração do regime hidrológico de jusante, além de propor os limites preventivos para a sustentabilidade. O estudo foi desenvolvido no reservatório de Ponte de Pedra, localizado no rio Correntes, divisa dos estados de Mato Grasso e Mato Grosso do Sul (Centro Oeste do Brail), na fronteira entre o Pantanal e o Planalto. O reservatório apresentou prolongado período de estratificação vertical (mistura no inverno) dos parâmetros físicos e químicos da água nas partes médias e profundas, mantendo-se homogêneo na parte superior, onde se encontra a captação, não alterando as características da água de jusante. Entre os fatores analisados, o vento foi o único fator que influenciou significativamente a estrutura vertical da qualidade da água sendo beneficiada pelas características morfométricas e construtivas do reservatório. Longitudinalmente, a formação do reservatório alterou significativamente quatro dos dez parâmetros analisados, com redução média de 38% da turbidez, 28% do fósforo total, 23% dos sólidos totais e 14% do nitrato. Destes, apenas a turbidez e o nitrato foram afetados pelo controle operacional do tempo de retenção hidráulica. Em relação à alteração dos parâmetros do regime hidrológico anual, dos 31 analisados, os parâmetros de vazões mínimas de curta duração (1, 3 e 7 dias), vazões máximas de 90 dias e o número de pulsos baixos e altos foram significativamente alterados pela operação do reservatório. Destes, a vazão máxima de 90 dias e o número de pulsos altos resumem os impactos, e podem ser utilizados como parâmetros alvos para restauração e conservação do regime hidrológico. As vazões sazonais também foram significativamente alteradas, com maior impacto na estação seca (inverno). Com base na variabilidade natural do rio, foram propostos os limites preventivos para a sustentabilidade, com alterações diárias permitidas de ±18% no inverno, ±24% na primavera e ±22% no verão e outono, aplicados sobre a vazão natural. De maneira geral, as alterações na qualidade da água e no regime hidrológico provocado pela formação e operação do reservatório foram consideradas baixas, tanto em número de parâmetros alterados quanto nas magnitudes das alterações, e estas foram atribuídas às baixas concentrações de partículas e nutrientes na bacia, ao sistema de captação superficial, o curto tempo de retenção hidráulica, pequena capacidade de regularização associadas à sazonalidade no regime de chuvas e ventos na região, que limitam manobras operacionais para a maximização da eficiência energética.
The formation of reservoirs changes the quality and quantity of water, both upstream and downstream, and the direction and magnitude of such changes depend on their characteristics of construction, operation, morphometry, as well as hydrological regime and climate of the region. However, much of this knowledge was based on large reservoirs, which is not the reality of the Pantanal, an area that is being impacted by a growing number of reservoirs with low capacity for regularization, raising questions about possible effects on the floodplain functioning. In this way, this study aimed (i) to identify the key factor in the process of stratification and vertical mixing of the reservoir, and whether this can influence the water quality, (ii) to evaluate the effects of the reservoir formation and operation on the quality of water upstream and downstream of the reservoir, and (iii) to examine the effects of the reservoir operation on the downstream hydrological regime, in addition to propose preventive limits for sustainability. The study was conducted at Ponte de Pedra Reservoir, located on the Correntes river, the motto between the states of Mato Grasso and Mato Grosso do Sul (Central West Brazil), on the border between the Plateau and the Pantanal. The reservoir had an extended period of vertical stratification (mixture in the winter) of physical and chemical water parameters in the medium and deep parts of the water column, being homogeneous in the upper part where the water is capitation, without changing the characteristics of the downstream water. Among the factors analyzed, the wind was the only factor that significantly influenced the vertical structure of the water quality, favored by morphometric and constructive characteristics of the reservoir. Along the longitudinal axis, the reservoir formation significantly altered the turbidity and concentrations of total phosphorus, total solids, and nitrate, with mean reduction of 38, 28, 23 and 14% of their values. Among these, only turbidity and nitrate were affected by the operational control of the hydraulic retention time. In relation to the change in parameters of the annual hydrological regime, parameters of short-term minimum flows (1, 3 and 7 days), maximum flows of 90 days and the number of low and high pulses were significantly modified by the reservoir operation. Of these, the maximum flow of 90 days and the number of high pulses have summarized the impacts, and can be used as target parameters for restoration and conservation of the hydrological regime. Seasonal flows were also significantly altered, with the greatest impact in the dry season (winter). Based on the natural variability of the river, it was proposed preventive limits for sustainability, with permitted daily changes of ±18% in winter, ±24% in spring and ±22% in summer and autumn applied on the natural flow. In general, changes in water quality and hydrological regime caused by the reservoir formation and operation were considered low, both in number of altered parameters as magnitudes of such changes, and these characteristics were ascribed to low concentrations of particles and nutrients in the basin, to the surface capitation system, short hydraulic retention time, low capacity of regularization associated with the seasonality of the regime of rainfall and wind in the region, limiting operational maneuvers for maximizing the energy efficiency.

The Pozzolane Rosse ignimbrite [PR] (457±4 ka) in the Alban Hills Volcanic District, Rome, Italy was exposed ~ 40 ka prior to a subsequent volcanic event which coverd it entirely. XRF, XRD, and clay separation results from PR samples from INGV and CA1 boreholes and Castel di Leva quarry show evidence of paleopedogenesis. All locations display loss of base cations, loss of K is consistent with XRD datat showing dissolution or alteration of leucite to analcime. Accumulation of Al and high L.O.I. support XRD evidence of 1:1 clay species at upper depth. Data suggest alteration extent can be determined by geochemistry. Hydrothermal alteration is assessed from geochemistry showing significant leaching of major and trace elements, primary mineralogy loss and iron sulfide and sulfate mineral development. Deep samples of PR may show groundwater influenced alteration with the presence of expandable 2:1 clays, zeolites, and possible mixing with the underlying Vallerano Lava.

Un sistema de gestión de sequías apropiado requiere de la anticipación de los posibles efectos que un episodio de este tipo tenga sobre el sistema de recursos hídricos. Esta tarea sin embargo resulta más complicada de lo que parece. En primer lugar, debido al alto grado de incertidumbre existente en la predicción de variables hidrológicas futuras. Y en segundo, debido al riesgo de sobrerreacción en la activación de medidas de mitigación generando falsa sensación de escasez, o sequía artificial. A este respecto, los planes especiales de sequía proveen de herramientas para la gestión eficiente de situaciones con escasez de recursos y la preparación de cara a futuros eventos. De todos modos, las diferentes estrategias de operación seguidas en cada sistema de recursos hídricos hacen que las herramientas que en algunos casos resultaron altamente útiles no lo sean tanto cuando se aplican en sistemas distintos. Debido a la falta de tiempo y/o al exceso de confianza en los trabajos realizados por terceros, con excelentes resultados en sus respectivos casos, a veces se cae en el error de implementar metodologías no del todo apropiadas en sistemas con requisitos completamente distintos. El desarrollo y utilización de metodologías generalizadas aplicables a diferentes sistemas y capaces de proporcionar resultados adaptados a cada caso es, por tanto, muy deseable. Este es el caso de las herramientas de modelación de sistemas de recursos hídricos generalizadas. Estas permiten homogeneizar los procesos mientras siguen siendo los suficientemente adaptables para proporcionar resultados apropiados para cada caso de estudio. Esta tesis presenta una serie de herramientas destinadas a avanzar en el análisis y comprensión de los sistemas de recursos hídricos, haciendo énfasis en la prevención de sequías y la gestión de riesgos. Las herramientas desarrolladas incluyen: un modelo de optimización generalizado para esquemas de recursos hídricos, con capacidad para la representación detallada de cualquier sistema de recursos hídricos, y una metodología de análisis de riesgo basada en la optimización de Monte Carlo con múltiples series sintéticas. Con estas herramientas es posible incluir tanto la componente superficial como la subterránea del sistema estudiado dentro del proceso de optimización. La optimización está basada en la resolución iterativa de redes de flujo. Se probó la consistencia y eficiencia de diferentes algoritmos de resolución para encontrar un balance entre la velocidad de cálculo, el número de iteraciones, y la consistencia de los resultados, aportando recomendaciones para el uso de cada algoritmo dadas las diferencias entre los mismos. Las herramientas desarrolladas se aplican en dos casos de estudio reales en la evaluación y posibilidad de complementación de los sistemas de monitorización y alerta temprana de sequías existentes en los mismos. En el primer caso, se propone un enfoque alternativo para la monitorización de la sequía en el sistema de operación anual del río Órbigo (España), complementándolo con la utilización de la metodología de análisis de riesgo. En el segundo caso, las herramientas se emplean en un sistema con una estrategia de operación completamente distinta. Se estudia como el análisis de riesgo de la gestión óptima puede ayudar a la activación anticipada de los escenarios de sequía en los sistemas de los ríos Júcar y Turia, cuya operación es hiperanual. En esta ocasión, el sistema de indicadores existente goza de una gran confianza por parte de los usuarios. La metodología de análisis de riesgo es, sin embargo, capaz de anticipar los eventos de sequía con mayor alarma, aspecto que es deseable si se quiere evitar que los episodios en desarrollo vayan a más. En ambos casos se muestra como la evaluación anticipada de las posibles situaciones futuras del sistema permiten una definición confiable de los escenarios de sequía con suficiente antelación para la activación efectiva de medidas de prevención y/o mitigación en caso de ser necesarias. La utilización de indicadores provenientes de modelos frente a indicadores basados en datos observados es complementaria y ambos deberían utilizarse de forma conjunta para mejorar la gestión preventiva de los sistemas de recursos hídricos. El empleo de modelos de optimización en situaciones de incertidumbre hidrológica es muy apropiado gracias a la no necesidad de definir reglas de gestión para obtener los mejores resultados del sistema, y teniendo en cuenta que las reglas de operación habituales pueden no ser completamente adecuadas en estas ocasiones.
Haro Monteagudo, D. (2014). Methodology for the optimal management design of water resources system under hydrologic uncertainty [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/45996
TESIS

Altered flow regimes following river regulation can result in significant changes in river bed geomorphology and subsequent negative ecological impacts caused by re-suspended sediments deposited on the riverbed. This study aimed to evaluate the consequences of implementing an ecological flow regime on sediments accumulated within the regulated river Juktån. Sediments were sampled and analysed for particle size distribution to estimate sediment stability. Flow alteration following the ecological flow regime was analysed with HEC-RAS unsteady flow simulation serving as a basis for calculations of forces acting to erode or retain deposited sediments. Additional analyses regarding critical flow were made with HEC-RAS steady flow simulation. Results show that 4 out of 15 cross-sections analysed would have the potential to erode and re-suspend sediments. The estimated average critical flow for when sediments become unstable with potential to re-suspend is 17 m3/s. The total sediment inventory of the studied reach is ~25000 ton, with ~3000-ton sediments potentially eroding into re-suspension. This is approximately 3% of river Umeälvens annual 100 000 ton suspended sediments before being regulated. Results indicate that river bed heterogeneity in river Juktån could benefit from implementing the ecological flow regime while not mobilizing such amounts of fine sediments that would cause clogging effects downstream the site of interest. The study also introduces the erosion rate equation which compares the annual erosion between two different flow regimes.

La thèse porte sur l’optimisation de la gestion du patrimoine culturel et historique à l'aide des méthodologies avancées d'inspection tout en s’appuyant sur le projet HeritageCare.La réponse à cette problématique est posée en cinq chapitres : (1) un état de l’art des méthodologies de gestion préventive, du projet HeritageCare et de l’identification de l’état de dégradation, (2) la mise en place de la méthodologie générale de la gestion préventive décomposée en quatre étapes (l’anamnèse, le diagnostic, la thérapie et le contrôle), (3) la proposition de modèles d’agrégation (4), les résultats de l’application de la démarche de gestion préventive et enfin (5) ceux de l’application des modèles. Ces derniers permettent de hiérarchiser les bâtis sur la base de 37 critères organisés en sous critères et indicateurs, de mettre en évidence la prise de décision des propriétaires sur la base de matrice de criticité combinant les valeurs des indicateurs, de déterminer la durée de vie résiduelle des bâtis sur la base de courbes d’altérations, de proposer et de hiérarchiser des actions de maintenance en s’appuyant sur une base de données développée. La méthodologie est illustrée par son application à quatorze bâtis représentant le patrimoine culturel et historique français
The objective of the thesis is to optimize the management of cultural and historical building heritage using advanced inspection methodologies with HeritageCare project.The answer to this problem is detailed in five chapters: (1) a state of the art of preventive management methodologies, the HeritageCare project and the identification of the state of degradation, (2) the implementation of the general methodology on preventive management is decomposed into 4 steps (anamnesis, diagnosis, therapy and control), (3) proposal of aggregation models (4), results of the application of the management approach preventive and finally (5) the application of models. These make it possible to prioritize the buildings on the basis of 37 criteria organized into sub-criteria and indicators, highlight the decision-making of the owners on the basis of a criticality matrix combining the values ​​of the indicators, determine the useful life of the buildings with the deterioration curves, propose and prioritize maintenance actions based on a developed database.The methodology is illustrated by its application on fourteen buildings representing the French cultural and historical heritage

碩士
國立臺灣大學
土木工程學研究所
101
The use of synthetic streamflow is particularly useful for water resources engineering. In the past decades, successful application of synthetic hydrologic sequences has been recognized for traditional engineering purposes, such as reservoir operation, water supply and flood control. With the increasing attention for the ecosystem, hydraulic engineering has to appropriately consider the ecological needs. However, the use of synthetic streamflow for ecological purpose has never been carefully examined. Hence a question is raised, could traditional synthetic streamflow approach provide reasonable result for determining ecological conditions? For this reason, this study addresses the reproduction of ecological patterns by synthetic streamflow generation model. The Tanshui River in Taiwan is used as a case study. We consider several combinations of different synthetic flow methods to examine this issue. Following approaches are considered, (1) Pure synthetic simulation model (2) Long term simulation and daily disaggregation models. The long term simulation models used in this study are SAMS-2007 and Modified k-NN bootstrap non-parametric approach. These models are applied to generate annual or monthly flow data according to historical record. Then Shot noise and k-NN based disaggregation models are applied to generate the daily flow. According to daily flow data generated, the Indicators of Hydrologic Alterations (IHA) program is used to quantify ecological patterns. By comparing the difference of 32 IHA indicators between historical and generated flow data, we evaluate the reproduction of different daily flow generation models in ecological characteristics. For the perspective of ecological needs, this study discusses the advantage and disadvantage of synthetic streamflow generation models and makes suggestion for their application for facilities design process.

碩士
國立成功大學
水利及海洋工程學系碩博士班
96
The variability of the natural flow regime has a strong influence on the stream ecosystems. By examining the relationships between stream ecosystems and hydrologic characteristics, we can understand the preference of different organisms to flow regimes. The development of the ecohydrological indicators is quite important to the management of ecological flow. By using principal component analysis (PCA) and structural equation modeling (SEM), we select the ecohydrological indicators that could express the significance of hydro-climate, water quality and fish species diversity. Then the logistic regression analysis model is used to examine the relation between fish and hydrologic indicators by using fish's present conditions. The structural equation modeling provides examination of a set of relationships between one or more independent variables and one or more dependent variables, so the modeler could explicitly capture the unreliability of measurement in the model, which in theory allows the structural relations between latent variables to be accurately estimated. In this study, the structural equation model is used to build five water quality models and one biodiversity model. The water quality model examines the causality of hydrologic indicators and River Pollution Index (RPI), which expresses the relationship between the hydrological indicators and water quality condition, and the biodiversity model examines the causality of hydrological indicators and Shannon Index (SI), which expresses the relationship between hydrological indicators and biodiversity. By analyzing water quality and biodiversity models, a suite of hydrological indicators representing multiple characteristics can be obtained. The ecohydrological indicators selected from this research can not only provide the specific hydrologic and water quality information that fish requires, but also can provide the guidance for water resources authorities to achieve the goal of ecological restoration.

In this study Bradford’s (2008) approach for setting ecological flow and water level targets is tested and refined through application within the Lake Simcoe Region Conservation Authority’s (LSRCA) subwatershed of Lover’s Creek. A method for defining subwatershed objectives and identifying habitat specialists through expert input is proposed and tested. The natural regime of each streamflow and wetland site is characterized along with the hydrological alteration at each site. Potential ecological responses to the hydrologic alterations are then hypothesized for the different types of changes calculated at each site. Methods for setting overall ecosystem health and specific ecological objective flow targets are proposed and tested. These targets are integrated into a flow regime for each site and a process for using this information for decision making is suggested. Flow magnitude quantification is attempted using hydraulic modelling and sediment transport equations, however the data used were found to be inadequate for this application. The accuracy of the targets developed using the method presented in this paper is mainly limited by the accuracy of the hydrological model and quantified flow magnitudes. Recommendations for improving these components of the assessment are made. The unique approach and recommendations presented in this paper provide explicit steps for developing flow targets for subwatersheds within the LSRCA. This research contributes toward the advancement of EFA within the LSRCA, which provides opportunity for enhanced protection and restoration of ecosystem health across the watershed.
Lake Simcoe Region Conservation Authority

Tracking and quantifying hydrologic change in urbanizing watersheds is a complex problem which can vary spatially and temporally throughout the effective catchment area as change occurs. Hydromodification due to urbanization usually results in a larger peak event stream discharge, a change in typical event volume, a reduced lag time between rainfall and stream discharge events, and a more complex falling hydrograph. Recently extracted Environment Canada data have allowed the creation of a high resolution instantaneous stream flow dataset dating to the late 1960s for many Ontario gauge stations. Hydrometric data were obtained for fifteen urban and semi-urban catchments within Southern Ontario ranging in size from ~50km² to 300 km² with urbanized land use assemblages varying from <5% to 80%. Utilizing automated methods, each individual runoff event from the hydrographic record was identified and characterized. Temporal changes to urban land area, land use, and road length were quantified for each watershed from aerial photography spanning the period of record at approximately 8 year intervals allowing identified trends in event hydrograph parameters to be correlated quantitatively with the alteration of the catchment over time.
Increasing trends in event peak discharge were identified in all but one study catchment. Event volume was found to be consistently increasing in most of the urban watershed, while trends in event duration were observed but with no clear increasing or decreasing trend. The lack of consistent trends in the timing and distribution of flow during runoff events suggest that build-out, drainage network design, and stormwater management systems play differing roles in the neighbouring urban catchments. Changes to flood recurrence intervals through the period of urbanization were also investigated; peak magnitude of high frequency events is affected to a greater extent than low frequency or flood events. The relative change in return frequency distribution is not consistent between catchments, also the degree of alteration can differ between various recurrence intervals at a gauge. Peak discharge of some return periods appeared to decrease with urban development suggesting that the increased detention brought with urban stormwater management systems have effectively offset the increased runoff due to additional impervious area and improved drainage efficiency. A consistent relationship defining the change in geomorphically significant return periods (i.e. channel forming flow) with urbanization was identified in neighbouring urban catchments.

Anthropogenically-induced climate change has the potential to have serious implications on aquatic ecosystems and may ultimately affect the supply and quality of freshwater lakes and rivers throughout the world. As a class of ecosystems, inland waters are vulnerable to climatic change and other pressures, due to their small size and their position in the landscape. There is therefore a need to assess the impact of projected climatic change on aquatic ecosystems. Owing to this need, ecological indicators have been developed as a method of quantifying, identifying, monitoring and managing the ecological integrity of aquatic environments. The aim of this research was to develop techniques in order to conceptualise the higher order impacts of projected climate change on environmentally related streamflows and water temperature in South Africa, and to simulate these using an appropriate hydrological model. For this dissertation the downscaled daily climate output from the ECHAM5/MPI-OM General Circulation Model (GCM) was used as an input into the daily time step conceptualphysical ACRU Agrohydrological Modelling System in order to simulate the impacts of projected climate change on selected eco-hydrological indicators at the Quinary Catchment spatial scale. In this research these indicators were grouped into two broad categories: 1. Ecological Flow Indicators and 2. Water Temperature Indicators. The results of this research took the form of maps and time series graphs. The ecological flow indicator results investigate the magnitude and duration of flow events and were analysed spatially for the 5 838 hydrologically interlinked and cascading Quinary Catchments constituting the southern Africa study region. The ECHAM5/MPI-OM GCM projects the magnitude and duration of both annual subcatchment runoff and accumulated streamflows to increase in the eastern parts of southern Africa for the intermediate future climate scenario (2046 - 2065), with this trend strengthening in the distant future climate scenario (2081 - 2100). The computationally intensive water temperature indicator results were analysed spatially at the scale of the Thukela Catchment. The Thukela catchment was selected as a case study area because of its diversity - in altitude, rainfall, soils and ecological regions, as well as in its population geography and levels of education and employment. This diversity presents a challenge to studies of impacts of projected climate change, including its potential impacts on water temperatures. The spatial analyses indicate that subcatchment runoff, accumulated streamflows and mixed maximum water temperature are all likely to increase under projected future climate conditions. A temporal investigation, in the form of time series analyses, focused on four water temperature indicators and was performed for 15 selected Quinary Catchments, located within the Thukela Catchment. These temporal analyses indicate that the absolute variability (i.e. standard deviation) of both individual subcatchment runoff and accumulated catchment streamflows, are projected to increase in the future, while the relative variability (i.e. coefficient of variation) is likely to remain much the same or even decrease slightly over time period. These temporal analyses also indicate that there is a noticeable difference in the mixed maximum water temperature within a single Quaternary Catchment due to hydrological flow routing, with an increase in water temperatures as the water cascades downstream from the upper Quinaries to the Quinaries at lower altitudes. The techniques developed and used in this research could aid decision makers involved in ecological and water management planning.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

The connection between water and human wellbeing is increasingly causing concern about the implications of water scarcity on poverty. The primary fear is that water scarcity may not only worsen poverty, but may also undermine efforts to alleviate poverty and food insecurity. A review of literature revealed that the relationship between water scarcity and poverty is a complex one, with water scarcity being both a cause and consequence of poverty. Furthermore, water scarcity is multidimensional, which makes it difficult to define, while it can also vary considerably, both temporally and spatially. Finally, the relationship between water scarcity and poverty is a difficult one to quantify. Within the context of water scarcity, indicators are viewed by many development analysts as appropriate tools for informing and orienting policy-making, for comparing situations and for measuring performance. However, simplistic traditional indicators cannot capture the complexity of the water-poverty link; hence a proliferation of more sophisticated indicators and indices since the early 1990s. The Water Poverty Index (WPI), one of these new indices, assesses water scarcity holistically. Water poverty derives from the conceptualisation of this index which relates dimensions of poverty to access to water for domestic and productive use. However, the WPI has not been applied extensively at meso-catchment scale, the scale at which water resources managers operate. In South Africa, the Thukela Catchment -in the province of KwaZulu-Natal presents a unique opportunity to assess the WPI at this scale. The Thukela is a diverse catchment with respect to physiography, climate and (by extension) natural vegetation, land use, demography, culture and economy. While parts of the catchment are suitable for intensive agricultural production and others are thriving economic centres, a large percentage of the population in the catchment lives in poverty in high risk ecosystems, with their vulnerability exacerbated by policies of the erstwhile apartheid government. Many rural communities, a high percentage of which occupy these naturally harsh areas, have low skills levels, with a high proportion of unemployed people, low or no income and low services delivery. Infrastructural development, which relates to municipal service delivery, is often made prohibitively expensive by the rugged terrain in which many people live. As in other catchments in South Africa, the Thukela is affected by policies and initiatives aimed at accomplishing the objectives of post-1994 legislation such as the South Africa Constitution and the National Water Act. The potential of the WPI to assess the impacts of these initiatives on human wellbeing and to inform decision .making in the Thukela catchment was investigated. An analysis of a 46 year long series of monthly summations of daily values of streamflows output by the ACRU agrohydrological simulation model has shown that the Thukela, in its entirety , is a water-rich catchment. The reliability of the streamflows, which has implications for communities who collect water directly from 1 streams, is high along main channels but can be considerably less along low order tributaries of the main streams. The flow reliability along the small tributaries is less in winter than in summer. A high percentage of the catchment's population, in addition to being poor and not having access to municipal services, live near, and rely on, the small tributaries for their water supplies. Admittedly, this analysis addresses only one dimension of water poverty, viz. physical water shortage. Nevertheless, the study revealed that despite the Thukela's being a water-rich catchment, many communities are still water stressed. A more holistic characterisation of the water scarcity situation in the Thukela catchment was achieved using the WPI. A review of possible information sources for computing the WPI in South Africa found that many monitoring programmes, information systems and databases are either in existence and are active, or being restructured, or are under different stages of development. If and when they are all fully functional , they should be able to support national assessments of the WPI at meso-scale without the need to collect additional information. A combination of information from some of the active databases and secondary data from other local studies was used to compute the WPI in the Thukela catchment. The assessment uncovered the following: • There is an apparent association between water poverty and socio-economic disadvantage in the Thukela catchment. • There was an improvement in the water poverty situation in most parts of the Thukela catchment between 1996 and 2001, although the degree of improvement varied from subcatchment to subcatchment. Climate change, if it manifests itself by higher temperatures and reduced rainfall, will most likely worsen water poverty throughout the Thukela catchment, with the subcatchments in which many of the poor communities are located being more likely to experience the most severe impacts as the coping capacities of those communities are already strained under current climatic conditions. The findings of this study illustrate the potential of WPI as a tool for informing decision making and policy evaluation at the meso-catchment scale at which many water-related decisions are made.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.