The object of this thesis si to evaluate the interaction of groundwater and surface water under the period of hydrological drought in the floodplain of the upper Lužnice river. The thesis tries to show the influence of the groudwater in the river floodplain during the period of hydrological drought and its correlation with the surface water state. The area of interst of the upper Lužnice is characterized by a unique ecosystem of unique natural value. It is a preserved river floodplain, which plays an irreplaceable role in fluvial processes, especially in water retention. The objectives were solved based on the monitoring of groudwater and surface water states from data obtained from the PřF UK profiles, which are represented by boreholes aross the floodplain and level meters in the watercourse. From the data obtained, it was possible to create a final analysis and to determine the behaviour and the mutual interaction between the surface water and groundwater in this natural floodplain. A detailed analysis has confirmed, that the interaction between watercourse and the floodplain and its retention potential. It can be said that during the hydrological drought, the water state or discharge in the watercourse is improved by water from the floodplain. The subsidy is only evident in certain stretches of...

The ability to anticipate and evaluate the combined impacts of urbanization and climate change on streamflow regimes is critical to developing proactive strategies that protect aquatic ecosystems. I developed an interdisciplinary modeling framework to compare and contrast the effectiveness of integrated stormwater management, or its absence, with two regional growth patterns for maintaining streamflow regimes in the context of climate change. In three adjacent urbanizing watersheds in Oregon's Willamette Valley, I conducted a three-step sequence to: 1) simulate land use change under four future development scenarios with the agent-based model Envision; 2) model resultant hydrological change under the recent past and two future climate regimes using the Soil and Water Assessment Tool; and 3) assess scenario impacts on streamflow regimes using 10 ecologically significant flow metrics. I evaluated each scenario in each basin using a flow metric typology based on the magnitude of change in each metric and the degree to which such changes could be mitigated, i.e., insensitive, sensitive and manageable, and sensitive and resistant. My results demonstrated distinct signatures of urbanization and climate change on flow regimes. Urbanization and climate change in isolation led to significant flow alterations in all three basins. Urbanization consistently led to increases in flow regime flashiness and severity of extreme flow events, whereas climate change primarily caused a drying trend. Climate change tended to exacerbate the impacts of urbanization but also mitigated urban impacts on several metrics. The combined impacts of urbanization and climate change caused substantial changes to metric sensitivities, which further differed by basin and climate regime, highlighting the uncertainties of streamflow regime responses to development and the value of spatially explicit modeling that can reveal complex interactions between natural and human systems. Scenario comparisons demonstrated the importance of integrated stormwater management and, secondarily, compact regional growth. My findings reveal the need for regional flow-ecology research that substantiates the ecological significance of each flow metric, develops specific targets for manageable ones, and explores potential remedies for resistant ones. The interdisciplinary modeling framework shows promise as a transferable tool for local watershed management. This dissertation includes previously unpublished co-authored material.

Lagoons are coastal waterbodies which are sensitive to meteorological and hydrological changes. This study focused on the spatial distribution of salinity in Gialova lagoon, Greece. The area in which the lagoon is located is under pressure from agriculture and truism in the area. Besides that, the lagoon is an important stop for migratory birds as well as the home for rare species. To investigate how salinity is distributed in the lagoon a salinity gradient was produced. Also, an attempt was made to model the salt and fresh water fluxes in the lagoon using a mass balance approach. The water fluxes are either from fresh water sources or influx of saline water from the sea. Manual electric conductivity measurements were taken during a field campaign to the lagoon. Time series data used in the model was obtained from stations in the lagoon and the surroundings. An investigation in how the lagoon measurement station differ in salinity was also performed in this study. Results from the gradient map and manual measurements show that the water in the lagoon is the freshest in the North-Eastern parts and the most saline to the South-West. The modelled water fluxes show an inverse relationship from each other. High fresh water fluxes correspond to precipitation events, lower salinity concentration. Whereas high salt water fluxes correspond to high salinity concentration and lowered precipitation. The stations concentrated to the middle lagoon show corresponding values in salinity whereas the station to the South-West differs. The canal surrounding the lagoon shows interactions since measurements show that the water is brackish. A longer time series could provide patterns in water fluxes over time. Trying to find the portions of terrestrial groundwater and surface water, and further investigation of the regional aquifer could provide new information to develop this model. The region is expected to experience water stress which makes further studies and monitoring important.

O crescimento populacional e a degradação dos corpos d’água vêm exercendo pressão à agricultura moderna, a proporcionar respostas mais eficientes quanto ao uso racional da água. Para uma melhor utilização dos recursos hídricos, faz-se necessário compreender o movimento da água na natureza, onde o conhecimento prévio dos fenômenos atmosféricos constitui uma importante ferramenta no planejamento de atividades que utilizam os recursos hídricos como fonte primária de abastecimento. Nesse trabalho foram realizadas previsões de longo prazo com antecedência de sete meses e intervalo de tempo mensal de níveis no Sistema Hidrológico do Taim, utilizando previsões de precipitação geradas por um modelo de circulação global. Para realizar as previsões foi elaborado um modelo hidrológico empírico de regressão, onde foram utilizadas técnicas estatísticas de análise e manipulação de séries históricas para correlacionar os dados disponíveis aos níveis (volumes) de água no banhado. Partindo do pressuposto que as previsões meteorológicas são a maior fonte de incerteza na previsão hidrológica, foi utilizada a técnica de previsão por conjunto (ensemble) e dados do modelo COLA, com 30 membros, para quantificar as incertezas envolvidas. Foi elaborado um algoritmo para gerar todas as possibilidades de regressão linear múltipla com os dados disponíveis, onde oito equações candidatas foram selecionadas para realizar as previsões. Numa análise preliminar dos dados de entrada de precipitações previstas foi observado que o modelo de circulação global não representou os extremos observados de forma satisfatória, sendo executado um processo de remoção do viés. O modelo de empírico de simulação foi posteriormente executado em modo continuo, gerando previsões de longo prazo de níveis para os próximos sete meses, para cada mês no período de junho/2004 a dezembro/2011. Os resultados obtidos mostraram que a metodologia utilizada obteve bons resultados, com desempenho satisfatórios até o terceiro mês, decaindo seu desempenho nos meses posteriores, mas configurando-se em uma ferramenta para auxílio à gestão dos recursos hídricos do local de estudo. / Population growth and degradation of water bodies have been pressuring modern agriculture, to provide more efficient responses about the rational use of water. For a better use of water resources, it is necessary to understand the movement of water in nature, where prior knowledge of atmospheric phenomena is an important tool in planning activities that use water as the primary source of supply. In this study were performed long-term forecasts of water levels (seven months of horizon, monthly time-step) in the Hydrological System Taim, using rainfall forecasts generated by a global circulation model as input. To perform predictions was developed an empirical hydrological regression model. This model was developed based on statistical techniques of analysis and manipulation of historical data to correlate the input data available to the levels (volume) of water in a wetland. Assuming that weather forecasts are a major source of uncertainty in hydrological forecasting, we used an ensemble forecast from COLA 2.2 with 30 members to quantify the uncertainties involved. An algorithm was developed to generate all the multiple linear regression models with the available data, where eight candidates equations were selected for hydrological forecasting. In a preliminary analysis of the precipitation forecast was observed that the global circulation model did not achieve a good representation of extremes values, thus a process of bias removal was carried out. Then the empirical model was used to generate water levels forecast for the next seven months, in each month of the period june/2004 to december/2011. The results showed that the methodology used has a satisfactory performance until the lead time three (third month in the future) where the performance starts to show lower values. Beside the sharply lost of performance in the last lead times, the model is a support tool that can help the decision making in the management of water resources for the study case.

A aplicação de modelos hidrológicos vem sendo bastante utilizada como apoio à tomada de decisão no planejamento dos recursos hídricos. Tendo em vista que os dados que servem de entrada para esses modelos estão sujeitos a erros diversos, o presente estudo teve o intuito de contribuir com o conhecimento do impacto desses erros no desempenho do modelo e na estimativa de seus parâmetros. O modelo analisado foi o IPH II fazendo uso do programa computacional WIN_IPH2. Entendendo que a avaliação da sensibilidade ainda é uma área que requer mais estudos, o presente trabalho é focado na utilização das análises de sensibilidade estática e dinâmica. Para isso foram geradas diversas séries temporais de dados de entradas do modelo hidrológico obtidas pela perturbação da série de dados observados. A perturbação foi representada por erros aleatórios (seguindo uma distribuição normal ou uniforme) ou sistemáticos incorporados ás séries temporais das variáveis: precipitação e evapotranspiração. Posteriormente, as análises de sensibilidade estática e dinâmica foram executadas. Para efetuar o acompanhamento da interferência dos erros, na eficiência do modelo, foi feita a avaliação dos resultados obtidos com a aplicação do modelo WIN_IPH2 para diferentes medidas de desempenho, e verificado o impacto dos erros nos dados de entrada no desempenho do modelo (sensibilidade estática) e no desempenho do modelo e na estimativa dos parâmetros (sensibilidade dinâmica). Na análise de sensibilidade estática verificou-se o decaimento mais acentuado da eficiência do modelo, em comparação com a análise de sensibilidade dinâmica, onde o modelo consegue contornar os erros nos dados de entrada com a alteração dos valores dos parâmetros. Por fim, o presente estudo confirmou as conclusões obtidas em estudos anteriores: Oudin et al. (2006), Andréassian et al. (2004), Kavetski et al. (2003). Além disso, o presente estudo apontou para outros fatores, na medida em que, observa-se junto à tendência do desempenho do modelo cair quando a intensidade do erro gerado é elevada, a importância de avaliar o possível comprometimento de dados em eventos extremos, uma vez que, nessa situação o desempenho do modelo passa a ser afetado de forma mais acentuada. / The hydrologic models had been used to support the decision making in water resources management. Since the input data of those models are subject to several kinds of errors, this study aimed to assess how this errors affect the model performance and the estimate of its parameters. The hydrologic model IPH II was used. Perceiving that the sensitivity analysis is still a field that requires further knowledge, this study was focused in the use of the dynamic and the static sensitivity procedures. In this sense, several time series of input data were obtained through the perturbations of an observed time serie. The perturbation was represented by the addition of random errors (with a normal or uniform distribution) or systematic errors to the observed time series of evapotranspiration and precipitation. Then, the static and dynamic sensibility analysis were performed. The effect of input data errors was assessed for several calibration processes of the IPH II using several performance measures. Thus, modification of the model performance (static sensitivity analysis) and model performance and parameter estimation (dynamic sensitivity analysis) were estimated. In the static sensitivity analysis it was found a most pronounced decay of the model efficiency in comparison with the dynamic sensitivity analysis, where the model can circumvent the errors in the input data with modification of the optimum parameter values. Finally, this study confirmed the conclusions of other previous studies as Oudin et al. (2006), Andréassian et al. (2004), Kavetski et al. (2003). In addition this study found other factors, as was observed that if the intensity of the error is high in an extreme event of precipitation, it reduced the model performance more than when it is low, in spite of the time series of errors have the same statistics.

Submitted by RITA DE CASSIA FERREIRA DA SILVA null (rita.cfs2@gmail.com) on 2016-02-14T16:55:59Z No. of bitstreams: 1 Dissertação de mestrado_Rita de Cássia Agronomia.pdf: 2314077 bytes, checksum: e4b86acfe4bca41a9fe1260dc9396e39 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-02-15T11:44:29Z (GMT) No. of bitstreams: 1 silva_rcf_me_bot.pdf: 2314077 bytes, checksum: e4b86acfe4bca41a9fe1260dc9396e39 (MD5) / Made available in DSpace on 2016-02-15T11:44:29Z (GMT). No. of bitstreams: 1 silva_rcf_me_bot.pdf: 2314077 bytes, checksum: e4b86acfe4bca41a9fe1260dc9396e39 (MD5) Previous issue date: 2015-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A crescente utilização dos recursos hídricos tem aumentado a demanda por novas fontes de abastecimento. A exploração dos aquíferos se tornou uma alternativa para captação de água potável em regiões onde a captação das águas superficiais é limitada. Assim, torna-se necessário o monitoramento entre a oferta e a demanda por água, principalmente, em regiões de relevante interesse econômico e de vulnerabilidade ecológica. O objetivo desse trabalho foi analisar as oscilações dos níveis freáticos do Sistema Aquífero Bauru (SAB), na Estação Ecológica de Santa Bárbara (EEcSB) localizada em Águas de Santa Bárbara – estado de São Paulo. As análises foram realizadas a partir de um modelo autorregressivo de series temporais com o software HARTT (Hydrograph Analysis: Rainfall and Time Trend), e sua relação com a vegetação de Cerrado e as espécies exóticas. A partir dos níveis de dezesseis poços instalados na EEcSB coletados entre março de 2010 e março de 2015 e das médias mensais de precipitação coletados a partir de 1987. O comportamento dos níveis freáticos foi analisado em função da sazonalidade e da vegetação. O modelo HARTT demonstrou-se eficiente ao ser capaz prever tendências futuras nas oscilações dos níveis freáticos. As análises demonstraram que a cobertura vegetal não interferiu de forma significativa no ciclo hidrológico para que causasse grandes déficits no lençol freático, uma vez que a mesma contribui na manutenção do ciclo hidrológico na região da EEcSB. / The overuse of water resource has been increasing the demand for new water sources. Groundwater reserves and aquifers have been exploited as an alternative to surface water in water scarcity areas. Therefore, monitoring the water supply and demand is necessary, particularly in regions of economic interest and ecological vulnerability. The aim of this study is to analyze groundwater variations in the Bauru Aquifer System (BAS), located in the Ecological Station of Santa Barbara (EEcSB), São Paulo state. The analyses were performed using an autoregressive time series model using HARTT software (Hydrograph Analysis: Rainfall and Time Trend). We analyzed the relationship among the surface and groundwater levels, the seasonality and vegetation parameters, such as native species from Cerrado biome, and exotic species. The groundwater levels data were collected for five years – 2010 to 2015 – in sixteen wells in EEcSB. We also accessed precipitation information since 1987. Our results showed the HARTT model was accurate to predict future oscillation trends of groundwater levels. The vegetation cover did not affect negatively the hydrological cycle, causing no significant groundwater deficit; on the other hand, the vegetation cover likely explain the maintenance of natural hydrological cycle in the EEcSB region.

Made available in DSpace on 2014-06-11T19:26:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-12-10Bitstream added on 2014-06-13T20:54:19Z : No. of bitstreams: 1 cucolo_ff_me_rcla.pdf: 421868 bytes, checksum: 77b170aee7a37f3fcdaa490d2c6cf75a (MD5) / Este trabalho atende projetos que pretendem utilizar análises hidrológicas em sistemas de informação geográfica até então pouco exploradas. Analises hidrológicas para inundação são realizadas a anos, porem ainda pouco exploradas quando o assunto é voltado ao mapeamento. Este projeto tem como objetivo determinar uma análise geográfica sobre inundação, explorando os métodos disponíveis para sistema de informações geográficas, assim como explorá-los detalhadamente. Neste estudo a aplicação se deu em uma obra linear – dutovia. / This work meets projects that intend to use hydrological analysis in geographic information systems, today few explored. Hydrologic analysis for flooding are carried out to years, but still poorly exploited when it is back to mapping. This project to determine a geographical analysis of flood, exploring the methods available for geographic information systems, and exploit them further. In this study the application was in a pipeline.

Doctor of Philosophy / Department of Biological & Agricultural Engineering / Aleksey Y. Sheshukov / As the world faces an increasing demand for food due to the growing global population and the pernicious effects of land degradation, there is a need to overcome this challenge by using sustainable management practices for agricultural productions. One of the problems, which sustainable agriculture seeks to address, is the loss of topsoil due to soil erosion. Changing weather patterns also contribute to the average annual rainfall across the globe with an excess precipitation, which creates runoff and causes soil erosion. One of the significant yet less studied types of soil erosion is ephemeral gully erosion. Formed by the concentrated overland flow during intensive rainfall events, ephemeral gullies are channels on agricultural fields that can be removed by tillage operations but appear at the same location every year. Even though simplified ephemeral gully models estimate soil losses, they do not account for complicated hydrological and soil erosion processes of channel formations. The purpose of this research work is to investigate sediment sources and develop tools that can predict ephemeral gully erosion more efficiently. To achieve this goal, an experimental study was conducted on an agricultural field in central Kansas by tracking channel development, monitoring soil moisture content, and recording the amount of rainfall. Runoff and sediment loads from contributing catchment and critical and actual shear stresses were estimated by the computer model, and conclusions were made on the effect of saturation dynamics on the erosion processes. Furthermore, a two-dimensional subsurface water flow and soil erosion model was developed with the variable soil erodibility parameters which account for the subsurface fluxes and the effects on the soil detachment process. The model was applied to study the impacts of variable soil erodibility parameters on the erosion process for different soils and various antecedent soil moisture conditions. Also developed to estimate the soil losses at the field scale was an integrated spatially-distributed ephemeral gully model with dynamic time-dependent channel development. The model showed good fit by matching the experimental data. The results from this work can be used to advance the research of soil erosion prediction from concentrated flow channels and ephemeral gullies formed on agricultural fields.

abstract: Ecohydrological responses to rainfall in the North American monsoon (NAM) region lead to complex surface-atmosphere interactions. In early summer, it is expected that soil properties and topography act as primary controls in hydrologic processes. Under the presence of strongly dynamic ecosystems, catchment hydrology is expected to vary substantially in comparison to other semiarid areas, affecting our understanding of ecohydrological processes and the parameterization of predictive models. A large impediment toward making progress in this field is the lack of spatially extensive observational data. As a result, it is critical to integrate numerical models, remote sensing observations and ground data to understand and predict ecohydrological dynamics in space and time, including soil moisture, evapotranspiration and runoff generation dynamics. In this thesis, a set of novel ecohydrological simulations that integrate remote sensing and ground observations were conducted at three spatial scales in a semiarid river basin in northern Sonora, Mexico. First, single site simulations spanning several summers were carried out in two contrasting mountain ecosystems to predict evapotranspiration partitioning. Second, a catchment-scale simulation was conducted to evaluate the effects of spatially-variable soil thickness and textural properties on water fluxes and states during one monsoon season. Finally, a river basin modeling effort spanning seven years was applied to understand interannual variability in ecohydrological dynamics. Results indicated that ecohydrological simulations with a dynamic representation of vegetation greening tracked well the seasonal evolution of observed evapotranspiration and soil moisture at two measurement locations. A switch in the dominant component of evapotranspiration from soil evaporation to plant transpiration was observed for each ecosystem, depending on the timing and magnitude of vegetation greening. Furthermore, spatially variable soil thickness affects subsurface flow while soil texture controls patterns of surface soil moisture and evapotranspiration during the transition from dry to wet conditions. Finally, the ratio of transformation of precipitation into evapotranspiration (ET/P) and run off (Q/P) changed in space and time as summer monsoon progresses. The results of this research improve the understanding of the ecohydrology of NAM region, which can be useful for developing sustainable watershed management plans in the face of anticipated land cover and climate changes. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2014

Les eaux résiduaires urbaines du bassin versant du lac du Bourget sont largement collectées et traitées. Les gestionnaires du lac s'interrogent, dans le contexte de l'évolution climatique et de l'évolution des usages des sols, sur l'impact et les modalités de maîtrise des pertes en phosphore et en particulier de la contribution des sources diffuses d'origine agricole. La thèse vise à modéliser les régimes d'exportation du phosphore vers le lac, dans la perspective de tester des scénarios de maîtrise des flux. Elle s'inscrit dans un dispositif de recherche opérationnelle CIFRE entre le bureau d'étude SAFEGE et l'UMR CARRTEL, en partenariat avec le CISALB (Comité Intersyndical pour l'Assainissement du Lac du Bourget). Dans ce cadre, deux sous bassins versants expérimentaux emboîtés représentatifs de la géographie du bassin du Bourget, (l'un rural dominé par l'élevage laitier de 250 ha, l'autre périurbain et agricole de 6800 ha) ont été équipés et suivis à leur exutoire durant une période de 18 mois. Les suivis hydrochimiques ont permis une caractérisation qualitative et quantitative des régimes d'exportations à l'exutoire de chaque bassin versant (flux hydrologique, de matières en suspension, du phosphore total, particulaire, et dissous, et de certaines formes d'azote – nitrate, ammonium). Ces flux ont été modélisés à l'aide du modèle SWAT. Pour rendre compte de certains processus spécifiques de mobilisation et de transfert de la charge en phosphore, des développements ont été mis en œuvre (extension de l'aire de saturation des sols en relation avec la mise en charge des nappes, stockages transitoires, remobilisations au sein du réseau hydrographique) qui constituent une des principales avancées de la thèse. Les résultats obtenus apportent une amélioration des connaissances scientifiques sur les mécanismes de transfert du phosphore. Les développements en termes de modélisation constituent un outil adapté pour accompagner la mise en place d'un plan d'actions visant la réduction des flux de phosphore parvenant au lac du Bourget, ceci dans la perspective des évolutions climatiques. / Urban wastewater are now widely collected and treated. Many questions still remain about the impact of climatic or anthropic evolution on the mobilisation and the transfer of phosphorus to Lake Bourget. This work deals with hydrological and nutrient modelling to understand phosphorus mobilization and transfers processes and to test mitigation options. Thesis is supported by a CIFRE agreement between SAFEGE office and UMR CARRTEL, in partnership with the CISALB. In this context, 2 experimental watersheds nested and variable in land uses (one agricultural of 250 ha, the other suburban and agricultural of 6,800 ha) were instrumented and followed at their outlet over a period of 18 months (continuous measurement of flow and some key parameters of physico-chemical water quality). Hydro-chemical measurements led to a qualitative and quantitative characterization of the exports regime at the outlet of each watershed (water flow, suspended solids, some forms of phosphorus – total, particulate, dissolved - and nitrogen). The exports were then modeled. To account for some specifics processes of mobilization and transfer of phosphorus (variable source areas, "in-stream" processes), some developments of the SWAT model were implemented. IIn this context, this works provides an improved scientific understanding of the mechanisms of transfer of phosphorus. Modeling tool can support the development of mitigation options for best management practices included in the framework of the "Lake Bourget watershed contract".