É realizada neste trabalho uma análise de sensibilidade das variáveis de entrada na determinação de hidrogramas de cheia em bacias hidrográficas desprovida de dados hidrológicos. Analisou-se a influência do CN (número de curva), da área de drenagem, do tempo de concentração, da duração da chuva e do período de retorno sobre os hidrogramas de cheia calculados. É feita uma comparação entre os métodos do hidrograma do SCS, Santa Bárbara e Clark. Para dar subsídio às análises de sensibilidade, utiliza-se o sistema de suporte à decisão ABC 6, desenvolvido na Universidade de São Paulo (USP). Um estudo de aplicação prática é elaborado para avaliar a influência da vazão no projeto de estruturas hidráulicas. Os resultados mostram quanto as variáveis de entrada influenciam na determinação das vazões e quanto estas vazões influenciam no projeto das estruturas hidráulicas. Como recomendação geral, visto a facilidade no uso de ferramentas computacionais e sistemas de suporte a decisão, sugere-se que sempre seja realizada uma análise de sensibilidade nos estudos hidrológicos. A análise de sensibilidade irá permitir a avaliação dos erros e incertezas que são cometidos quando da adoção das variáveis de entrada. / A sensitivity analysis of input variables for flood hydrographs determination in watersheds without observed hydrological data is presented in this work. Influence of CN (number of curve), drainage area, time of concentration, rainfall duration and return period on the calculated flood hydrographs is analyzed. It is made a comparison among three unit hydrographs methods: SCS, Santa Barbara and Clark. ABC 6, a decision support system developed at USP (Universidade de São Paulo) is used as a tool for sensitivity analysis. A study of practical application is made to examine the influence of flow in design of hydraulic structures. Results show how input variables influence calculated flows and how these flows influence design of hydraulic structures. It is suggested, by the fact that computational tools and decision support systems are easy to use, that a sensitivity analysis in hydrological studies must be always be performed. Sensitivity analysis will allow evaluation of hydrologic design results due to errors and uncertainness caused by input variables.

É realizada neste trabalho uma análise de sensibilidade das variáveis de entrada na determinação de hidrogramas de cheia em bacias hidrográficas desprovida de dados hidrológicos. Analisou-se a influência do CN (número de curva), da área de drenagem, do tempo de concentração, da duração da chuva e do período de retorno sobre os hidrogramas de cheia calculados. É feita uma comparação entre os métodos do hidrograma do SCS, Santa Bárbara e Clark. Para dar subsídio às análises de sensibilidade, utiliza-se o sistema de suporte à decisão ABC 6, desenvolvido na Universidade de São Paulo (USP). Um estudo de aplicação prática é elaborado para avaliar a influência da vazão no projeto de estruturas hidráulicas. Os resultados mostram quanto as variáveis de entrada influenciam na determinação das vazões e quanto estas vazões influenciam no projeto das estruturas hidráulicas. Como recomendação geral, visto a facilidade no uso de ferramentas computacionais e sistemas de suporte a decisão, sugere-se que sempre seja realizada uma análise de sensibilidade nos estudos hidrológicos. A análise de sensibilidade irá permitir a avaliação dos erros e incertezas que são cometidos quando da adoção das variáveis de entrada. / A sensitivity analysis of input variables for flood hydrographs determination in watersheds without observed hydrological data is presented in this work. Influence of CN (number of curve), drainage area, time of concentration, rainfall duration and return period on the calculated flood hydrographs is analyzed. It is made a comparison among three unit hydrographs methods: SCS, Santa Barbara and Clark. ABC 6, a decision support system developed at USP (Universidade de São Paulo) is used as a tool for sensitivity analysis. A study of practical application is made to examine the influence of flow in design of hydraulic structures. Results show how input variables influence calculated flows and how these flows influence design of hydraulic structures. It is suggested, by the fact that computational tools and decision support systems are easy to use, that a sensitivity analysis in hydrological studies must be always be performed. Sensitivity analysis will allow evaluation of hydrologic design results due to errors and uncertainness caused by input variables.

The ability of an organism to disperse to suitable habitats, especially in modified and fragmented systems, determines individual fitness and overall population viability. The bluehead sucker (Catostomus discobolus), flannelmouth sucker (Catostomus latipinnis), and roundtail chub (Gila robusta) are three species native to the upper Colorado River Basin that now occupy only 50% of their historic range. Despite these distributional declines, populations of all three species are present in the San Rafael River, a highly regulated tributary of the Green River, Utah, providing an opportunity for research. Our goal was to determine the timing and extent of movement, habitat preferences, and limiting factors, ultimately to guide effective management and recovery of these three species. In 2007-2008, we sampled fish from 25 systematically selected, 300-m reaches in the lower 64 km of the San Rafael River, spaced to capture the range of species, life-stages, and habitat conditions present. We implanted all target species with a passive integrated transponder (PIT) tag, installed a passive PIT tag antennae, and measured key habitat parameters throughout each reach and at the site of native fish capture. We used random forest modeling to identify and rank the most important abiotic and biotic predictor variables, and reveal potential limiting factors in the San Rafael River. While flannelmouth sucker were relatively evenly distributed within our study area, highest densities of roundtail chub and bluehead sucker occurred in isolated, upstream reaches characterized by complex habitat. In addition, our movement and length-frequency data indicate downstream drift of age-0 roundtail chub, and active upstream movement of adult flannelmouth sucker, both from source populations, providing the lower San Rafael River with colonists. Our random forest analysis highlights the importance of pools, riffles, and distance-to-source populations, suggesting that bluehead sucker and roundtail chub are habitat limited in the lower San Rafael River. These results suggest management efforts should focus on diversifying habitat, maintaining in-stream flow, and removing barriers to movement.

Previous hydrometric studies demonstrated the prevalence of overland flow as a hydrological pathway in the tropical rain forest catchment of South Creek, northeast Queensland. The purpose of this study was to consider this information in a mixing analysis with the aim of identifying sources of, and of estimating their contribution to, storm flow during two events in February 1993. K and acid-neutralizing capacity (ANC) were used as tracers because they provided the best separation of the potential sources, saturation overland flow, soil water from depths of 0.3, 0.6, and 1.2 m, and hillslope groundwater in a two-dimensional mixing plot. It was necessary to distinguish between saturation overland flow, generated at the soil surface and following unchanneled pathways, and overland flow in incised pathways. This latter type of overland flow was a mixture of saturation overland flow (event water) with high concentrations of K and a low ANC, soil water (preevent water) with low concentrations of K and a low ANC, and groundwater (preevent water) with low concentrations of K and a high ANC. The same sources explained the streamwater chemistry during the two events with strongly differing rainfall and antecedent moisture conditions. The contribution of saturation overland flow dominated the storm flow during the first, high-intensity, 178-mm event, while the contribution of soil water reached 50% during peak flow of the second, low-intensity, 44-mm event 5 days later. This latter result is remarkably similar to soil water contributions to storm flow in mountainous forested catchments of the southeastern United States. In terms of event and preevent water the storm flow hydrograph of the high-intensity event is dominated by event water and that of the low-intensity event by preevent water. This study highlights the problems of applying mixing analyses to overland flow-dominated catchments and soil environments with a poorly developed vertical chemical zonation and emphasizes the need for independent hydrometric information for a complete characterization of watershed hydrology and chemistry.

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. <br> 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.

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. <br> 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.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第14136号 / 工博第2970号 / 新制||工||1441(附属図書館) / 26442 / UT51-2008-N453 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 中川 一, 教授 関口 秀雄, 教授 藤田 正治 / 学位規則第4条第1項該当

Magister Scientiae - MSc (Environ & Water Science) / Studies have shown that the primary origin of salinity in river flows of the Sandspruit in the Berg Catchment located in the Western Cape Province of South Africa was mainly a result of atmospheric deposition of salts. The salts are transported to rivers through surface runoff and subsurface flow (i.e. through flow and groundwater flow). The purpose of this study was to determine the contributions of subsurface and surface flows to the total flows in the Sandspruit, Berg Catchment. Three rain events were studied. Water samples for two rain events were analysed for environmental tracers ?18O, Silica or Silicon dioxide (SiO2), Calcium (Ca2+) and Magnesium (Mg2+). Tracers used for two component hydrograph separation were ?18O and SiO2. The tracers, Ca2+ and Mg2+, revealed inconsistent contributions of both subsurface flow and surface flow. Two component hydrograph separations indicated is that groundwater is the dominant contributor to flow, while surface runoff mainly contributes during the onset of the storm event. Groundwater response to precipitation input indicated that boreholes near the river have a quicker response than boreholes further away from the river. Boreholes nearer to the river also indicate higher water levels in response to precipitation, in comparison to boreholes further from the river.

Magister Scientiae - MSc (Environ & Water Science) / Studies have shown that the primary origin of salinity in river flows of the Sandspruit in the Berg Catchment located in the Western Cape Province of South Africa was mainly a result of atmospheric deposition of salts. The salts are transported to rivers through surface runoff and subsurface flow (i.e. through flow and groundwater flow). The purpose of this study was to determine the contributions of subsurface and surface flows to the total flows in the Sandspruit, Berg Catchment. Three rain events were studied. Water samples for two rain events were analysed for environmental tracers ?18O, Silica or Silicon dioxide (SiO2), Calcium (Ca2+) and Magnesium (Mg2+). Tracers used for two component hydrograph separation were ?18O and SiO2. The tracers, Ca2+ and Mg2+, revealed inconsistent contributions of both subsurface flow and surface flow. Two component hydrograph separations indicated is that groundwater is the dominant contributor to flow, while surface runoff mainly contributes during the onset of the storm event. Groundwater response to precipitation input indicated that boreholes near the river have a quicker response than boreholes further away from the river. Boreholes nearer to the river also indicate higher water levels in response to precipitation, in comparison to boreholes further from the river.

Orientador: Jose Teixeira Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-03T23:55:35Z (GMT). No. of bitstreams: 1 Ferreira_Lucia_D.pdf: 1500242 bytes, checksum: f168afe0384add0cf44eeb8198bdd9c6 (MD5) Previous issue date: 2004 / Doutorado / Agua e Solo / Doutor em Engenharia Agrícola