Climate change and population growth is putting increased pressure on water supply. However, detailed water-balance information, which would assist with management is lacking for major reservoirs around the world. This information is particularly critical in mid-latitude northern Mediterranean climates where evaporation is a potentially important water-balance component. This study examines the seasonality of the water balance for the Sooke Reservoir in western Canada, a major water supply for the City of Victoria, British Columbia. Evaporation is estimated with three evaporation models, Penman, Priestley-Taylor, and Hamon and the results are compared. Inflows are estimated with the contributing-area approach and the HBV-EC, hydrologic model. Finally, a worst-case drought scenario is created. If conditions of low precipitation and high evaporation like those found in the study period were to persist, water levels would become critically low during the third dry season and by the fifth season if water restrictions were put in place.

A ETA Guandu é de vital importância para o estado do Rio de Janeiro por ser responsável pelo abastecimento de 8,5 milhões de pessoas na Região Metropolitana. Este trabalho tem como objetivo efetuar uma análise qualitativa de sua vulnerabilidade, em relação à qualidade e quantidade de água captada, perante diversos fatores de estresse, visando dimensionar a importância da variabilidade climática na composição de sua vulnerabilidade. Adotou-se o conceito de vulnerabilidade como função da exposição (grau em que um sistema experimenta estresses), da sensibilidade (grau em que um sistema é afetado pelo estresse) e capacidade adaptativa (capacidade de um sistema de se ajustar, moderar ou lidar com as conseqüências de um estresse). Dessa forma, foi possível desenvolver uma metodologia de análise qualitativa de vulnerabilidade, específica ao caso da ETA Guandu, perante quatro fatores de estresse considerados como os mais determinantes para a vulnerabilidade atual: i) variabilidade climática; ii) transposição; iii) condições ambientais e qualidade da água e iv) acidentes ambientais. Os resultados evidenciaram que o maior grau de vulnerabilidade da ETA Guandu se relaciona à transposição, já que diversas partes de sua infraestrutura não dispõem de ações de manutenção preventiva. A vulnerabilidade devido às condições ambientais é também intensa, principalmente a turbidez no período chuvoso; entre 2000 e 2010, a ETA Guandu foi parcialmente paralisada 22 vezes em função do grande aporte de sedimentos. Não identificamos nenhum registro de paralisação total da ETA Guandu em função de acidentes ambientais, embora algumas vezes estes tenham imposto a paralisação da transposição. O componente variabilidade climática (intensificação de eventos hidrológicos extremos) revelou-se como o estressor menos determinante da vulnerabilidade atual.

Climate change and variability have great impact on the hydrological cycle and consequently on the availability of water resources. Variations in temperature and precipitation trends that are occurring are a consequent of the increase in the concentrations of greenhouse gases, which are subsequently affecting the hydrological cycle. This in turn affects water quantity and quality, which is essential for agriculture, domestic and industrial uses. This study, done in Elliot Town and the surrounding areas of Sakhisizwe Municipality in the Eastern Cape Province of South Africa, evaluates how climate change and variability is affecting water availability and its quality in the town. The impact climate change and variability on agricultural production is also assessed. Remote Sensing, Geographic Information Systems (GIS), databases and some statistical packages have been used to collect, analyse and create spatial maps used to derive concrete conclusions. The methods used aided in spatially analysing the changes in temperature and rainfall along the years and make a comparative analysis. The study has shown that the spatial changes in the amount, intensity and frequency of rainfall affects the magnitude and frequency of stream flows; consequently, increasing the intensity of floods and droughts that have been recurring in the last few decades. The municipality is more affected by climate variability than change, and the resultant extreme climate events are affecting the water resources resulting in domestic water cuts, poor water quality and low agriculture productivity. This study recommends the importance of an awareness campaigns on climate change and variability and their effect directed towards the community, especially on novel water harvesting technologies. The study also highlights the importance of a robust early warning system to prepare the community in case of a climate shock, which is an area that needs further research. / Environmental Sciences / M. Sc. (Environmental Science)

A ETA Guandu é de vital importância para o estado do Rio de Janeiro por ser responsável pelo abastecimento de 8,5 milhões de pessoas na Região Metropolitana. Este trabalho tem como objetivo efetuar uma análise qualitativa de sua vulnerabilidade, em relação à qualidade e quantidade de água captada, perante diversos fatores de estresse, visando dimensionar a importância da variabilidade climática na composição de sua vulnerabilidade. Adotou-se o conceito de vulnerabilidade como função da exposição (grau em que um sistema experimenta estresses), da sensibilidade (grau em que um sistema é afetado pelo estresse) e capacidade adaptativa (capacidade de um sistema de se ajustar, moderar ou lidar com as conseqüências de um estresse). Dessa forma, foi possível desenvolver uma metodologia de análise qualitativa de vulnerabilidade, específica ao caso da ETA Guandu, perante quatro fatores de estresse considerados como os mais determinantes para a vulnerabilidade atual: i) variabilidade climática; ii) transposição; iii) condições ambientais e qualidade da água e iv) acidentes ambientais. Os resultados evidenciaram que o maior grau de vulnerabilidade da ETA Guandu se relaciona à transposição, já que diversas partes de sua infraestrutura não dispõem de ações de manutenção preventiva. A vulnerabilidade devido às condições ambientais é também intensa, principalmente a turbidez no período chuvoso; entre 2000 e 2010, a ETA Guandu foi parcialmente paralisada 22 vezes em função do grande aporte de sedimentos. Não identificamos nenhum registro de paralisação total da ETA Guandu em função de acidentes ambientais, embora algumas vezes estes tenham imposto a paralisação da transposição. O componente variabilidade climática (intensificação de eventos hidrológicos extremos) revelou-se como o estressor menos determinante da vulnerabilidade atual.

Le changement climatique requiert une adaptation de la gestion des extrêmes hydrologiques (crues et étiages). Nos recherches proposent un cadre d’analyse de l’effet du changement climatique sur ces extrêmes dans le bassin transnational de la Meuse, par un chaînage de modèles (atmosphérique – hydrologique - hydraulique) liant le gradient régional de pression à l’écoulement mesuré à l’exutoire d’un bassin. Le forçage climatique est obtenu par l’agrégation de données climatiques historiques et de données multi-modèles issues de l’expérience CMIP5. En forçant deux sous-bassins de la Meuse (situés en France et en Belgique) à l’aide d’une première estimation de la variabilité climatique potentielle, nous montrons que les indicateurs de crues et d’étiages ainsi que les débordements de rivière peuvent être fortement impactés par le changement climatique anthropique. Cette analyse de vulnérabilité constitue un outil pour tester la robustesse de stratégies d’adaptation au changement climatique / Climate change requires to adapt management of streamflow extremes (floods and low flows). Our researches provide a framework to analyze climate change effect on the streamflow extremes in the transnational Meuse river basin, through a modelling chain (atmospheric model – hydrological model – hydraulic model) linking the pressure gradient force to the flow at the outlet of a basin. The climate forcing is obtained by blending historical data and multi-model data for the CMIP5 experience. By forcing two sub-basins of the Meuse river (located in France and Belgium) with the potential climate variability, we show that flood and low flows indices as well as river overflowing might be strongly impacted by the anthropogenic climate change. This analysis of catchment vulnerability is a robust tool to test climate resiliency of adaptation strategies for water management

Cette thèse a pour objectifs de documenter les variations spatiotemporelles de la zone de minimum d’oxygène (OMZ) du Pacifique Nord-Est, et d’identifier les mécanismes qui ont causé ces variations. L’étude est fondée sur l’analyse géochimique des composants majeurs, mineurs et traces de sédiments prélevés dans le Pacifique Nord-Est, en combinant des mesures par ICP-MS et scanneur XRF. Ces mesures ont permis de distinguer l’effet de la productivité biologique de celui de la ventilation océanique sur l’oxygénation du sédiment. J’ai pu mettre en évidence le rôle prépondérant de la productivité au niveau de la Basse Californie (23°N), qui varie en phase avec les températures en Atlantique Nord durant les 120.000 dernières années. Par ailleurs, la ventilation océanique a probablement joué un rôle important au niveau du golfe de Papagayo (12°N), par l’advection de masses d’eau provenant des hautes latitudes nord et sud. L’intensité de l’OMZ du Pacifique Nord-Est serait donc influencée par des modifications des circulations océaniques et atmosphériques, liées aux climats des hautes latitudes des deux hémisphères. / This thesis aims at documenting the spatiotemporal variations of the Oxygen Minimum Zone (OMZ) of the northeastern Pacific, and identifying the mechanisms that caused theses variations. The study is based on the geochemical analyses of major, minor, and trace elements of sediments from the northeastern Pacific, by combining ICP-MS and XRF scans measurements. These measurements allowed distinguishing the effect of biologic productivity and oceanic ventilation on sediment oxygenation. I was able to highlight the predominant impact of the productivity off the Baja California Margin (23°N), which varied in phase with the high northern Atlantic temperature across the past 120,000 years. Moreover, oceanic ventilation did play an important role off the Papagayo Gulf (12°N), because of the advection of water mass coming from the high northern and southern latitudes. OMS intensity in the northeastern Pacific could thus be influenced by changes in the atmospheric and oceanic circulation, in relation to high northern and southern latitudes climates.

Floods and droughts are frequent in Central America and cause large social, economic and environmental impacts. A crucial step in disaster risk reduction is to have a good understanding of the causing mechanisms of extreme events and their spatio-temporal characteristics. For this, a key aspect is access to a dense network of long and good-quality hydro-meteorological data. Unfortunately, such ideal data are sparse or non-existent in Central America. In addition, the existing methods for hydro-climatic studies need to be revised and/or improved to find the most suitable for the region’s climate, geography and hydro-climatic data situation. This work has the ultimate goal to support the reduction of risks associated with hydro-climatic-induced disasters in Central America. This was sought by developing ways to reduce data-related uncertainties and by improving the available methods to study and understand hydro-climatic variability processes. In terms of data-uncertainty reduction, this thesis includes the development of a high resolution air temperature dataset and a methodology to reduce uncertainties in a hydrological model at ungauged basins. The dataset was able to capture the spatial patterns with a detail not available with existing datasets. The methodology significantly reduced uncertainties in an assumed-to-be ungauged catchment. In terms of methodological improvements, this thesis includes an assessment of the most suitable combination of (available) meteorological datasets and drought indices to characterise droughts in Central America. In addition, a methodology was developed to analyse drought propagation in a tropical catchment, in an automated, objective way. Results from the assessment and the drought propagation analysis contributed with improving the understanding of drought patterns and generating processes in the region. Finally, a methodology was proposed for assessing changes in both hydrological extremes in a consistent way. This contrasts with most commonly used frameworks that study each extreme individually. The method provides important characteristics (frequency, duration and magnitude), information that can be useful for decisions within risk reduction and water management. The results presented in this thesis are a contribution, in terms of hydro-climatic data and assessment methods, for supporting risk reduction of disasters related with hydro-climatic extremes in Central America. / Översvämningar och torka inträffar ofta i Mellanamerika och orsakar stora skador på samhälle, ekonomi och miljö. En kritisk del av riskreduceringen är förståelsen av mekanismerna bakom extremhändelserna, och deras rumsliga och tidskarakteristik. En nyckelfaktor är tillgång till långa tidsserier av rumsligt täckande hydrometeorologiska data av bra kvalitet. I Mellanamerika är sådana ideala data tyvärr sällsynta eller saknas helt. Dessutom behöver befintliga metoder för hydro-klimatisk analys revideras och/eller förbättras för att identifiera de mest lämpade metoderna för regionens klimat, geografi och situationen vad gäller hydrologiska och meteorologiska data. Det övergripande syftet med denna avhandling har varit att stödja arbetet med riskreducering i Mellanamerika vid hydrologiska extremhändelser som sätts igång av extrema väderhändelser. För att bidra till detta utvecklades metoder för att minska datarelaterade osäkerheter och för att förbättra tillgängliga metoder för att studera och förstå de processer som ligger bakom variabiliteten i hydrologi och klimat. Dataosäkerheten minskades genom utveckling av ett nytt dataset för lufttemperatur med hög rumslig upplösning och en metodik för att begränsa osäkerheten i modellberäknad vattenföring i ett område där det saknas observationer. Det nya datasetet kunde fånga rumsliga mönster på en detaljnivå som hittills inte varit möjlig. Metodiken möjliggjorde en klar minskning i osäkerheten hos vattenföringen i ett avrinningsområde som behandlades som om det saknade data. Avhandlingen innehåller också en metodik för att fastlägga den mest lämpade kombinationen av tillgängliga klimatdataset och torkindex för att karakterisera torka i Mellanamerika. Därutöver utvecklades en metod för att studera torkans fortplantning i ett tropiskt avrinningsområde på ett objektivt och automatiserat sätt. Slutligen föreslås en metod för att hantera förändringar av både översvämning och torka på ett konsistent sätt  som förenklar användningen av resultaten  för en beslutsfattare. Dessa metoder bedömdes användbara för att förbättra karakteriseringen och förståelsen av extrema hydrologiska händelser i Mellanamerika. Resultaten i denna avhandling ger bidrag till förståelsen av hydrologiska och klimatextremer genom förbättrade data och analysmetoder som i förlängningen kommer att stödja riskreduceringsarbetet i Mellanamerika. / Las sequías e inundaciones son frecuentes en Centroamérica y causan grandes problemas sociales, económicos y ambientales. Un aspecto crucial en la reducción del riesgo consiste en entender los mecanismos que causan dichos eventos, y sus características espacio-temporales. Para lograr esto es necesario tener acceso a una red de datos hidro-meterológicos densa, con series largas, y de buena calidad. Desafortunadamente, este no es el caso en Centroamérica. Además, los métodos para hacer estudios hidro-climáticos requieren ser evaluados y/o mejorados para asegurar su aplicabilidad en la región (su clima, su geografía y los datos disponibles). Este trabajo tiene como meta apoyar la reducción del riesgo de desastres asociados a eventos hidro-meteorológicos extremos en Centroamérica. Esto se consigue a partir de la reducción de incertidumbres asociadas a los datos, y de la mejora de métodos para el estudio de la variabilidad hidro-climática. Para reducir la incertidumbre de los datos, este trabajo incluye el desarrollo de una base de datos de temperatura de alta resolución y el desarrollo de una metodología para reducir las incertidumbres en datos simulados de caudal. Con la nueva base de datos se logra reconocer patrones espaciales a un nivel de detalle no antes captado por otras bases de datos. Por otro lado, la metodología redujo significativamente las incertidumbres de los datos simulados de caudal. En cuanto a métodos, esta tesis incluye una evaluación para encontrar la mejor combinación de índices de sequía y base de datos para la caracterización de sequías en la región. Además, se desarrolló una metodología para analizar la propagación de la sequía en una cuenca tropical, de una manera objetiva y automatizada. Los resultados de estos dos pasos ayudaron a mejorar la comprensión de los patrones y los mecanismos de generación de las sequías. Finalmente, se incluyó un método para evaluar los cambios en los patrones de sequías e inundaciones de una manera consistente, y no de manera individual como usualmente se ha hecho. Así fue posible obtener la frecuencia, duración y magnitud en ambos extremos hidrológicos. Esta información podría constituir una herramienta  útil para el manejo del riesgo y del recurso hídrico.

Study region Nyangores River watershed, headwater catchment of Mara River basin in Kenya. Study focus Climate variability and human activities are the main drivers of change of watershed hydrology. The contribution of climate variability and land use change to change in streamflow of Nyangores River, was investigated. Mann Kendall and sequential Mann Kendall tests were used to investigate the presence and breakpoint of a trend in discharge data (1965–2007) respectively. The Budyko framework was used to separate the respective contribution of drivers to change in discharge. Future response of the watershed to climate change was predicted using the runoff sensitivity equation developed. New hydrological insights for the region There was a significant increasing trend in the discharge with a breakpoint in 1977. Land use change was found to be the main driver of change in discharge accounting for 97.5% of the change. Climate variability only caused a net increase of the remaining 2.5% of the change; which was caused by counter impacts on discharge of increase in rainfall (increased discharge by 24%) and increase in potential evapotranspiration (decreased discharge by 21.5%). Climate change was predicted to cause a moderate 16% and 15% increase in streamflow in the next 20 and 50 years respectively. Change in discharge was specifically attributed to deforestation at the headwaters of the watershed.

The diploma thesis titled Barriers of Development in Ethiopia: Structural Conditions and Strategies for Adaptation is focused on analysis of environmental risk factors and their impact on economic development of Ethiopia. It further evaluates the effectiveness of concrete adaptation measures on both official policy level and community level. The thesis departs from refined version of Jared Diamond's five point framework for analysis of collapse of complex societies. Contemporary scholarly discourse of rapid population growth, deforestation & land degradation and climate variability is formalized into causal schemes and supported by current statistical data. The thesis concludes that adopted measures have had only limited effect on elimination of the respective risk factors. Thus, Ethiopia remains a long-term recipient of foreign humanitarian assistance, without which it would fall into state of economic collapse. To overcome this situation Ethiopia needs to transform its subsistence agricultural production system.

Study region Nyangores River watershed, headwater catchment of Mara River basin in Kenya. Study focus Climate variability and human activities are the main drivers of change of watershed hydrology. The contribution of climate variability and land use change to change in streamflow of Nyangores River, was investigated. Mann Kendall and sequential Mann Kendall tests were used to investigate the presence and breakpoint of a trend in discharge data (1965–2007) respectively. The Budyko framework was used to separate the respective contribution of drivers to change in discharge. Future response of the watershed to climate change was predicted using the runoff sensitivity equation developed. New hydrological insights for the region There was a significant increasing trend in the discharge with a breakpoint in 1977. Land use change was found to be the main driver of change in discharge accounting for 97.5% of the change. Climate variability only caused a net increase of the remaining 2.5% of the change; which was caused by counter impacts on discharge of increase in rainfall (increased discharge by 24%) and increase in potential evapotranspiration (decreased discharge by 21.5%). Climate change was predicted to cause a moderate 16% and 15% increase in streamflow in the next 20 and 50 years respectively. Change in discharge was specifically attributed to deforestation at the headwaters of the watershed.