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1
Maze, Rex Allan II. "SWAT." Bowling Green State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1300235860.
2
Parajuli, Prem B. "SWAT bacteria sub-model evaluation and application." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/373.
3
Bhandari, Ranjit. "ANALYZING STREAMFLOW VARIABILITY UNDER CMIP5 PROJECTIONS USING SWAT MODEL." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2363.
Анотація:
For analyzing the effect of climate change on the streamflow at a regional scale, six General Circulation Models (GCMs) were selected from among eighteen GCMs from the Coupled Model Intercomparison Project (CMIP5) for the Pajaro River Watershed in central California. The 1/8° latitude-longitude resolution bias-corrected and downscaled CMIP5 projections were utilized for an ensemble of GCMs under four Representative Concentration Pathways (RCP2.6, RCP4.5, RCP6.0 and RCP8.5). The twenty-first century is segregated into three time-periods (2016-2039, 2040-2069 and 2070-2099) for comparing the streamflow against changing precipitation and temperature according to the CMIP5 projections. The daily maximum and daily minimum temperature are projected to consistently rise through to the latter part of the century. Csiro-mk3-6 and canesm2 models project an increase of 3.1°C in annual average daily maximum temperature and 3.4°C in annual average daily minimum temperature respectively in 2070-2099 period under RCP8.5 scenarios. Future precipitation is projected to increase in January and February, which means the wet months in the Pajaro River Watershed are likely to get more rainfall. The dry months would continue to receive diminished precipitation throughout the century. The streamflow was increasing on future January, and sporadically, in February months but diminished during the dry months. The range of annual average streamflow for the future years stretched from 0.1 to 29.1 m3/s for the GCM ensemble, mostly close to the lower limit. The results suggest considering multiple climate change scenarios and evaluating alternative setups would provide a robust basis for hydrological assessment.
4
Veiga, Aldrei Marucci. "Calibração do modelo hidrossedimentológico SWAT na bacia hidrográfica do córrego Samambaia, Goiânia - GO." Universidade Federal de Goiás, 2014. http://repositorio.bc.ufg.br/tede/handle/tede/3497.
Анотація:
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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
This research paper focus on the analysis of SWAT model calibration in terms of flow and sediment in Samambaia River Basin, a small watershed (32.78 km2) located at Goiânia, Brazil. Streamflow and suspended sediment daily measurements have been carried out by February to December 2013 and climatic data were obtained form a weather station located inside the basin. Terrain data such as Digital Elevation Model (DEM), soil types, and land use were on the SWAT autocalibration too as well as on SWAT-CUP software, which is a specific too for automatic calibration. Initially, the simulation run in SWAT overestimated values of runoff peak and underestimated minimum discharges. However, the peaks were minimized and minimum discharges were adjusted to the observed flows after sensitivity analysis. By using different optimization schemes (GLUE, PARASOL and SUFI-2) in SWAT-CUP, an automatic calibration analysis has been done, which presented a better fit to the observed values (start with streamflow, than move to sediment). Statistical analysis using the coefficient of Nash-Sutcliff efficiency (COE) resulted in 0.80 and 0.88 for runoff and suspended sediment, respectively, which are considered good fits between simulated and observed values. The CN parameter, which is related to soil type, land use, and infiltration, showed the highest sensitivity in the calibration. After that, the alpha factor of base flow was another which showed higher sensitivity. The higher value obtained for the Manning roughness coefficient allows runoff to be damped. With regard to sediment calibration, parameters of sediment from landscape (USLE_P and USLE_C) as well as parameters of sediment from channel (SPCON and SPEXP) have been used in the calibration, once that they have shown higher sensibility.
O objetivo desta pesquisa é fazer a análise da calibração do modelo SWAT em termos de fluxo e sedimentos na bacia do Córrego Samambaia, uma microbacia (32,78km2), localizada em Goiânia, Brasil. Medições diárias de vazões e sedimentos foram realizadas em Fevereiro a Dezembro de 2013, e os dados climáticos foram obtidos a partir de uma estação meteorológica localizada no interior da bacia. Dados do terreno, tais como Elevação Digital do Terreno (MDT), tipos de solos e usos da terra foram obtidos do Sistema de Informação e Estatística de Goiás (SIEG). Análises foram realizadas na ferramenta autocalibração do SWAT, bem como no software SWAT-CUP, que é uma ferramenta específica para a calibração automática. Inicialmente, a execução da simulação no SWAT superestimou os valores de pico do escoamento e subestimou as vazões mínimas. No entanto, os picos foram minimizados e as vazões mínimas foram ajustadas para os fluxos observados após análise de sensibilidade. Ao utilizar diferentes esquemas de otimização (GLUE, ParaSol e Sufi-2) no SWAT-CUP, uma análise de calibração automática foi feito, que apresentou um melhor ajuste aos valores observados (começando pela vazão a qual altera o sedimento). A análise estatística do coeficiente de eficiência de Nach-Sutcliffe (COE) resultou em 0,80 e 0,88 para o escoamento superficial e sedimentos em suspensão, respectivamente, que são considerados bons ajustes entre os valores simulados e observados. O parâmetro CN, que está relacionado com o tipo de solo, uso da terra e infiltração, apresentou maior sensibilidade na calibração. Depois disso, o fator alfa de fluxo de base foi outra que mostrou maior sensibilidade. Quanto maior for o valor obtido para o coeficiente de rugosidade de Manning permite que o escoamento seja amortecido. No que diz respeito a calibração dos sedimentos, os parâmetros de sedimentos de paisagem (USLE_P e USLE_C), bem como os parâmetros de sedimentos a partir do canal (SPCON e SPEXP) tem sido utilizados na calibração, uma vez que eles mostraram maior sensibilidade.
5
Palanisamy, Bakkiyalakshmi. "Evaluation of SWAT model - subdaily runoff prediction in Texas watersheds." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5921.
Анотація:
Spatial variability of rainfall is a significant factor in hydrologic and water
quality modeling. In recent years, characterizing and analyzing the effect of spatial
variability of rainfall in hydrologic applications has become vital with the advent of
remotely sensed precipitation estimates that have high spatial resolution. In this study,
the effect of spatial variability of rainfall in hourly runoff generation was analyzed using
the Soil and Water Assessment Tool (SWAT) for Big Sandy Creek and Walnut Creek
Watersheds in North Central Texas. The area of the study catchments was 808 km2 and
196 km2 for Big Sandy Creek and Walnut Creek Watersheds respectively. Hourly
rainfall measurements obtained from raingauges and weather radars were used to
estimate runoff for the years 1999 to 2003. Results from the study indicated that
generated runoff from SWAT showed enormous volume bias when compared against
observed runoff. The magnitude of bias increased as the area of the watershed increased
and the spatial variability of rainfall diminished. Regardless of high spatial variability,
rainfall estimates from weather radars resulted in increased volume of simulated runoff.
Therefore, weather radar estimates were corrected for various systematic, range-dependent
biases using three different interpolation methods: Inverse Distance
Weighting (IDW), Spline, and Thiessen polygon. Runoff simulated using these bias adjusted radar rainfall estimates showed less volume bias compared to simulations using
uncorrected radar rainfall. In addition to spatial variability of rainfall, SWAT model
structures, such as overland flow, groundwater flow routing, and hourly
evapotranspiration distribution, played vital roles in the accuracy of simulated runoff.
6
Tein, Jenn-Yun. "The subjective workload assessment technique (SWAT) : an application and evaluation /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487670346876945.
7
Qāsim, Muḥammad. "Modelling land use changes in Swat, Pakistan : spatial and temporal dynamics of land use change in Swat (1968-2007) : a Hindu Kush Himalayan region of Pakistan." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555847.
Анотація:
Swat is part of the high mountain Hindu-Kush Himalayan region of Pakistan, with diverse biophysical and socio-economic characteristics. The region is endowed with many fragile and fragmented ecosystems, where land use and land cover changes have accelerated processes with irreversible effects on ecosystems. The thesis aims to; 1) find evidence of land use and cover change in the context of very disparate accounts on the state of forest resources in Pakistan, and particularly in Swat; 2) analyze the drivers of change and model the impact of geophysical factors on land use change; and 3) to identify the socioeconomic driving foreces ofland use change and to reflect on governance and policy failures and discuss potential policy options for conserving forests given these trends. To achieve our aims we used remote sensing and GIS for temporal analysis of land use and land cover change for the years 1968, 1990 and 2007, and for analyzing the geophysical and socioeconomic driving forces behind these changes we used logistic regression, test statistics, household surveys and expert interviews. Based on remote sensing and GIS we could provide clear evidence for fragmentation and deforestation; which is contrary to official Pakistani sources. In high altitude ecosystem the forest area decreased by 30.5%, with 11.4% deforestation due to agricultural expansion; in the mid-elevation zone, agriculture expanded by 70.3% and forests decreased by 49.7%; and in the lower altitudes agriculture expansion was 129.9% consuming 31. 7% of the forest areas over the 40 years study period. Binomial logistic regression analysis of the geophysical factors showed that III the more vulnerable high altitude ecosystems, despite accessibility problems, agriculture expansion has been a significant factor mainly driven by off-season vegetable production. In the lower altitudes agriculture expansion on forested areas was mainly explained by proximity to main roads and markets. Similarly expansion of smallholder agriculture and built up areas in the three zones were explained by proximity to water sources, slope, aspect and distance to settlements. Overall, various degrees of population pressure combined with improved access to infrastructure and markets lead to various degrees of agricultural expansion and intensification as well as extension of built up land. This was combined with institutional shortcomings especially with regards to contested property rights and ineffectual governmental interference; For sustainable livelihood agricultural production could be enhanced through conservation of traditional crops diversity (instead of predominance of off-season vegetables) and scientific input enabling improvement in traditional soil conservation and fertility management to reduce the risks of agriculture abandonment on steep slopes in the long-term. Exploration of alternate resources of fuel and energy, coupled with strategic reforestation programmes can bea positive step to minimize forest degradation. Apart from that a carefully crafted reform program is required including the strengthening of property rights, provisions for communal management and market based incentives, depending on the social, economic, and ecological characteristics of the different zones under consideration. Only with such policies in place the current rapid rate of deforestation can be avoided and sustainable resource use be ensured.
8
Fall, Claudia. "Microbial Contamination Assessment with SWAT in a Tile-Drained Rural Watershed." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20057.
Анотація:
Microbial contamination of drinking water poses an important health risk which causes severe illnesses and epidemics. In order to improve surface and drinking water quality, the understanding of fecal pathogen contamination processes including their prevention and control needs to be enhanced. The watershed model soil water assessment tool (SWAT) is commonly used to simulate the complex hydrological, meteorological, erosion, land management and pollution processes within river basins. In recent years, it has been increasingly applied to simulate microbial contamination transport at the watershed scale. SWAT is used in this study to simulate Escherichia coli (E.coli) and fecal coliform densities for the agriculturally dominated Payne River Basin in Ontario, Canada. Unprecedented extensive monitoring data that consist of 30 years of daily hydrological data and 5 years of bi-weekly nutrient data have been used to calibrate and validate the presented model here. The calibration and validation of the streamflow and nutrients indicate that the model represent these processes well. The model performs well for periods of lower E. coli and fecal coliform loadings. On the other hand, frequency and magnitude of higher microbial loads are not always accurately represented by the model.
9
Rattray, Danny James. "Modelling herbicide movement from farm to catchment using the swat model." University of Southern Queensland, Faculty of Engineering and Surveying, 2008. http://eprints.usq.edu.au/archive/00006245/.
Анотація:
[Abstract]Water quality in Australia’s northern grains farming areas often exceeds water quality trigger values for suspended sediments, nutrients and some herbicides (CBWC, 1999). While there are many land uses in these areas that contribute to the resultant water quality, of particular concern for the grains farming industry is the widespread detection in rivers of chemicals used by their industry, namely atrazine and metolachlor. A comparison of Hodgson Creek catchment (South East Queensland, Australia) herbicide data with national water quality guidelines shows that trigger values are frequently exceeded. That water quality trigger values are exceeded is expected for a highly modified catchment such as Hodgson Creek, and the Australian New Zealand Environment and Conservation Council (ANZECC) (2000) guidelines make provision that in such catchments, locally derived targets should be set. Natural resource managers therefore require skills in linking planned management with their ability to set or meet targets. The opportunity suggested itself for using catchment modelling to set realistic targets for water quality based on the adoption of best management farming practices. This study investigated the suitability of the Soil and Water Assessment Tool (SWAT) to fulfil this modelling role in an Australian context of land use management. To test the suitability of SWAT to fulfil this role, the study aimed to determine the feasibility of using the model to explicitly depict farm management practices at a paddock scale to estimate resultant catchment water quality outcomes. SWAT operates as two distinct sub-models. A hydrologic response unit (HRU) (the paddock scale model) generates runoff and constituents, and the output of many HRU are summed and routed through a stream network. The method for calibration of SWAT proposed in the user manual (Neitsch et al., 2001) is to calibrate against streamflow before calibrating sediment and then herbicides. The logic of testing in a process dependent order is sensible, however the method proposed by Neitsch et al. (2001) assumes that the HRU processes are reliable and calibration only need consider catchment scale processes. A review of the literature suggested that there had been limited testing of HRU process in studies where SWAT had been applied. Data available for model testing came from both paddock and catchment studies. The effects of cultivation management practices on runoff and erosion have been well characterised for the study area by Freebairn and Wockner (1996). Atrazine dissipation in soil and loss in runoff was available from a study of a commercial farm in the Hodgson Creek catchment (Rattray et al, 2007). An ambient and event based water quality monitoring for suspended sediments and herbicides provided data for the Hodgson Creek catchment for the period 1999 to 2004 (Rattray, unpublished data). The model required minimal calibration to achieve good predictions of crop yields and surface cover for winter crops. However, testing of summer cropping component revealed structural problems in SWAT associated with the end of a calendar year. Testing also revealed that perennial pastures and trees are modelled with unrealistic fluctuations in biomass and leaf area index. The model was able to represent hydrology well across a range of scales (1-50,000 ha). Catchment scale runoff data was well matched for a range of tillage treatments. The model was found to be able to attain a good prediction of monthly runoff at the catchment scale. This is consistent with the finding of most other SWAT studies. The model was able to represent average annual erosion reasonably well using the Universal Soil Loss Equation (USLE) when tested at the HRU scale (1 ha) against a range of tillage management data. When tested at the catchment scale the model was found to be able to match average annual sediment loads for the catchment however annual variability in sediment loads was poorly matched. Testing of the herbicide model for SWAT found that model compared poorly with paddock scale trial data. The reason for poor model performance can be attributed to an inadequate representation of processes and model output was unrealistic compared to our understanding of herbicide transport processes. When the model was tested at a catchment scale it was found to compare very poorly with catchment scale observations. This can be explained in part by the deficiencies of the HRU herbicide model, but is also due in part to difficulties in parameterisation of spatial and temporal inputs at the catchment scale. While SWAT provides a model with detailed physical processes, the capacity to apply the model is let down by an ability to practically determine the spatial and temporal extent of the farming practices (i.e. where and when are tillage and herbicides applied in the catchment). The challenge to applying SWAT is that farming practices in Australia vary markedly from year to year. SWAT requires the user to input crop practices in as a fixed rotation while Australia’s highly variable climate with unreliable seasonal weather patterns results in opportunistic farming practices. Hence this is a major limitation in the models ability to predict catchment outcomes, particularly for herbicides where off site losses are highly dependant on application timing. In attempting to validate herbicide losses at the whole of catchment scale it became apparent that uncertainty in the temporal variation of farm operations within the catchment poses a major limitation to accurately reproducing observations at the catchment outlet. It is concluded that that there is limited usefulness of SWAT for investigating the impacts of land management on catchment scale herbicide transport for Australian conditions.
10
Kellndorfer, Laurie. "A hydrologic calibration of the SWAT model in Kranji Catchment, Singapore." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/73790.
Анотація:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 50-51).
The Public Utilities Board (PUB) of Singapore wishes to expand recreational activities in Singapore's surface waters through the Active, Beautiful, and Clean Waters Program (ABC Waters). One area of concern with ABC Waters is microbial pollution. Pathogens pose an immediate and substantial risk to human health when humans come into contact with contaminated water. In order to open surface waters for public recreation, PUB must insure that these waterways are free of pathogens. The Massachusetts Institute of Technology in the United States and Nanyang Technological University in Singapore are working together on several water quality research projects related to ABC Waters. A surface runoff model for Kranji Catchment, located in northwest Singapore, was created in the Soil and Water Assessment Tool (SWAT) by Granger (2010) and improved by Bossis (2011). The model incorporates hydrology, land use, weather, soil, and slope to calculate surface flows and water quality constituents. The model was originally created to be a prediction tool for bacteria concentrations in outflows throughout the Kranji Catchment. Earlier versions of the model, however, grossly underpredict flows. In an effort to improve the accuracy of the SWAT model, the surface hydrology was calibrated to flows measured at five stream gauge stations in Kranji Catchment. Precipitation within the SWAT model was changed to equal a rainfall record at one of the stream gauge stations. A sensitivity analysis was also conducted for surface flows. Surface flows were most sensitive to changes in six input parameters, and two of these parameters were changed in the final, calibrated model. The soil evaporation compensation factor (ESCO) was increased, and the curve number for moisture condition II (CN2) was decreased. These three changes in the model greatly improved the way the SWAT model predicts surface outflows, and with these changes, surface outflows predicted by the model match measured values very closely at all five stream gauge stations. While hydrologic calibration greatly improved surface flow calculations in the SWAT model, predictions of bacteria concentrations did not improve. The SWAT model still requires further calibration work to bring bacteria concentrations closer to measured values.
by Laurie Kellndorfer.
M.Eng.
11
Rosa, David Rafael Quintão. "Modelagem hidrossedimentológica na bacia hidrográfica do rio Pomba utilizando o Swat." Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/8197.
Анотація:
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
O excesso de sedimentos presentes nos cursos d' água pode ocasionar prejuízos ambientais, econômicos e sociais. Portanto, ferramentas computacionais capazes de simular adequadamente todos os processos relacionados à produção, transporte e deposição de sedimentos são considerados atualmente essenciais para o adequado planejamento e gestão de bacias hidrográficas. Desta forma, objetivou-se avaliar o desempenho do modelo SWAT (Soil and Water Assesment Tool) na estimativa da produção e transporte de sedimentos e também na avaliação dos impactos de possíveis mudanças no uso do solo na produção de sedimentos em condições edafloclimáticas de uma bacia hidrográfica do sudeste brasileiro. As informações necessárias para a representação da bacia do Rio Pomba utilizadas para a aplicação do SWAT foram o Modelo Digital de Elevação hidrograficamente consistente (MDEHC), os mapas de solo e de seu uso, dados de precipitação, vazão e de concentração de sedimentos em suspensão, disponibilizados pela ANA (Agência Nacional de Águas), dados climáticos, disponibilizados pelo INMET (Instituto Nacional de Meteorologia), e informações de solo obtidos no projeto RADAMBRASIL. Foi necessária a utilização de uma curva-chave de sedimentos para a geração da série contínua de concentração de sedimentos. Foi realizada a análise de sensibilidade para identificar entre os parâmetros do modelo aqueles que mais interferem no seu desempenho. Na sequência, o modelo foi calibrado para a vazão e concentração de sedimentos em suspensão, tendo como seção de controle a estação fluviométrica denominada Cataguases (58770000), utilizando o período de 01/01/1995 a 31/12/1999. Para a validação, foram empregados dois testes distintos: split sample test e proxy basin test. Com o intuito de avaliar a capacidade de utilização do modelo como ferramenta para prever impactos de possíveis mudanças no uso do solo na produção de sedimentos, foram simulados dois cenários: Cenário I: constituiu-se da substituição de área de pastagens por reflorestamento, prevendo um crescimento de 5% ao ano da área de reflorestamento em um período de 10 anos; Cenário II: constituiu-se da substituição de área de pastagens por agricultura, prevendo uma porcentagem de crescimento de 12% ao ano para o mesmo período utilizado no Cenário I. Ambos os cenários hipotéticos foram aplicados na área de drenagem referente à estação fluviométrica, denominada Usina Maurício, localizada a montante da seção de calibração. As análises estatísticas feitas para avaliar o desempenho do modelo nas etapas de calibração e validação foram o coeficiente de Nash e Sutcliffe (E NS ) e o percentual de viés das vazões e concentrações de sedimento em suspensão simuladas em relação às observadas (P BIAS ). Os resultados permitiram constatar que: a) os parâmetros para quais o modelo apresentou maior sensibilidade foram: número da curva inicial para a condição de umidade ACMII (CN2); armazenamento de água no solo (SOL_AWC); tempo de retardo do escoamento superficial direto (SURLAG); fator de práticas de manejo da USLE (USLE_P); declividade média da sub-bacia (SLOPE); coeficiente linear de fluxo de sedimentos (SPCON); condutividade hidráulica do solo saturado (SOL_K); e profundidade da camada de solo (SOL_Z); b) o modelo SWAT pode ser aplicado para simulação hidrossedimentológica na mesma seção de calibração, utilizando uma série temporal de dados diferente; c) o modelo SWAT pode ser aplicado para simulação hidrossedimentológica em seções a montante das quais foi calibrado, porém com características edafoclimáticas semelhantes à área de drenagem utilizada na calibração; d) na simulação de cenários hipotéticos de uso do solo, a substituição de áreas de pastagem por reflorestamento provocou uma redução na concentração média anual de sedimentos em suspensão. Entretanto, a substituição de áreas de reflorestamento por agricultura aumentou a concentração média anual de sedimento em suspensão.
Watercourses’ sediment excess can cause environmental, economic and social losses. Therefore, there are computational tools able to simulate properly all sediments related production, transport and deposition processes that are currently considered essential for the proper watershed planning and management. Thus, this study aimed to evaluate the SWAT (Soil and Water Assessment Tool) model performance to estimate sediments production and transport and also in assessing land usage changes’ possible impacts in sediments production in edaphoclimatic conditions of a river basin in Brazilian southeastern. The necessary information for the representation of Rio Pomba’s basin used for SWAT’s application were the Hydrologically Consistent Digital Elevation Model (MDEHC), the soil and their usage maps, rainfall data, flow and suspended sediment concentration, provided by ANA (Agência Nacional de Águas), weather data, provided by INMET (Instituto Nacional de Meteorologia), and soil information obtained in RADAMBRASIL project. The use of a sedimentation curve to generate the concentration sediment continuous series was required. The sensitivity analysis was performed to identify the model’s parameters which most affect on its performance. And so on, the model was calibrated to suspended sediment’s flow and concentration, with the drainage area related to the gaging station called Cataguases (58770000) as control section, using the period from 01/01/1995 to 12/31/1999. For validation two different tests were taken: Split Sample Test and Proxy Basin Test. In order to evaluate the model’s utilization capability as a tool to predict possible land use changes’ impacts in sediments production, two scenarios were simulated: Scenario I: consisted of pasture area substitution by reforestation, providing a 5% reforestation area growth per annum in a 10 year period; Scenario II: consisted of pasture area substitution by agriculture, allowing a 12% growth rate per annum for the same period as in Scenario I. Both hypothetical scenarios were applied in the drainage area concerning the gaging station called Usina Maurício, located upstream of the calibration section. The statistical analysis conducted to assess the model’s performance in the calibration and validation steps were the Nash and Sutcliffe (ENS) coefficient and the flow bias percentage and suspended sediment concentrations, simulated in relation to the observed ones (PBIAS). The results demonstrated that: a) the parameters to which the model showed higher sensitivity were: the initial curve number for moisture condition ACMII (CN2); soil water storage (SOL_AWC); direct runoff time delay (SURLAG); USLE practices management factor (USLE_P); sub-basin average slope (SLOPE); sediment flow linear coefficient (SPCON); saturated soil hydraulic conductivity (SOL_K); and soil layer depth (SOL_Z); b) the SWAT model can be applied to hydro-sedimentological simulation in the same calibration section using some different time series data; c) the SWAT model can be applied to hydro-sedimentological simulation to upstream sections of which it was calibrated, but with edaphoclimatic characteristics similar to the drainage area used for calibration; d) the SWAT model can be applied to hydro-sedimentological simulation at conditions of a Brazilian southeastern located watershed; e) to simulate hypothetical scenarios of land use, replacing pasture areas for reforestation resulted in a reduction in the annual average suspended sediment’s concentration. However, the reforestation areas replacement by agriculture increased the annual average suspended sediment’s concentration.
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Dias, Viviane de Souza. "SIMULAÇÃO DE VAZÃO APLICADA AO RESERVATÓRIO DA UHE FURNAS UTILIZANDO MODELO SWAT." Pontifícia Universidade Católica de Goiás, 2017. http://tede2.pucgoias.edu.br:8080/handle/tede/3679.
Анотація:
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The hydrological model Soil and Water Assessment Tool (SWAT) is an important tool in the management of water resources, and can contribute to the estimation of streamflow to hydroelectric reservoirs. The objective of this study was to simulate the flow in the drainage area of the Furnas reservoir, located in the Rio Grande basin (MG). The series of meteorological and hydrological data included in the study corresponded to the period from 01/01/1998 to 12/31/2013. In the development of the model the following steps were adopted: (1) parameterization of the input data; (2) configuration of the model; (3) warm up and simulation; (4) sensitivity analysis; (5) calibration, validation and analysis of results. Calibration, validation and uncertainty analysis were performed using the Sequential Uncertainty Fitting (SUFI-2) algorithm through the Uncertainty Calibration Program (SWAT-CUP). The calibration and validation adjustment was measured by applying the P-Factor (percentage of the measured data bracketed by the 95PPU), the R-Factor (mean uncertainty band thickness) and the Nash and Sutcliffe (NSE) objective function. The P-factor values corresponded to 0.94 and 0.69 for calibration and validation, respectively. The NSE values were 0.86 for the calibration and 0.64 for the validation. The results obtained show a reasonable precision in relation to the literature, being within acceptable intervals, characterizing the model as adequate to estimate reservoir flows, considering the uncertainties of prediction. The construction of models from the SWAT allows the definition of best practices of management of water resources and of hydroelectric reservoirs.
O modelo hidrológico Soil and Water Assessment Tool (SWAT) é uma importante ferramenta na gestão de recursos hídricos, podendo contribuir para estimativas de vazão a reservatórios hidrelétricos. O objetivo deste estudo foi simular a vazão na área de drenagem do reservatório da UHE Furnas, localizado na bacia do rio Grande (MG). A série de dados meteorológicos e hidrológicos incluída no estudo correspondeu ao período de 01/01/1998 à 31/12/2013. No desenvolvimento do modelo foram adotadas as etapas: (1) parametrização dos dados de entrada; (2) configuração do modelo; (3) aquecimento e simulação; (4) análise de sensibilidade; (5) calibração, validação e análise dos resultados. A calibração, validação e análise de incertezas foram realizadas utilizando o algoritmo Sequential Uncertainty Fitting (SUFI-2) através do Programa de Incerteza de Calibração (SWAT-CUP). O ajuste da calibração e validação foi mensurado aplicando o P-Fator (porcentagem de dados incluídos na faixa de incerteza de 95%), o R-Fator (espessura média da faixa de incerteza) e a função objetivo Nash e Sutcliffe (NSE). Os valores do P-Fator corresponderam a 0,94 e 0,69 para calibração e validação, respectivamente. Os valores do NSE foram de 0,86 para a calibração e 0,64 para a validação. Os resultados encontrados apresentam precisão razoável em relação à literatura, estando dentro de intervalos considerados aceitáveis, caracterizando o modelo como adequado para simular vazões ao reservatório, se consideradas as incertezas de predição. A construção de modelos a partir do SWAT permite a definição de melhores práticas de gerenciamento de recursos hídricos e de reservatórios hidrelétricos.
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Hewitt, David. "Exploring ore grindability tests with the steel wheel abrasion test (SWAT) machine." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86573.
Анотація:
Steel media wear has been well studied and quantified; one method of quantification is the Comminution Dynamics Lab's Total Media Wear model. It combines simulations, abrasion and corrosion experimental trials to determine wear for the components of milling and grinding ores and minerals for the mining industry. Breakage is an important measure of process efficiency, the greater the number of breakage events per unit energy consumed, the greater the throughput and production. The classic breakage parameter, the Bond Work Index generates an energy term used by mill operators to determine this performance criterion. It has been suggested that the abrasion test, used in the Total Media Wear Model, would be a suitable alternative to the labour and time-consuming Bond Locked-cycle Test. Extensive tests were performed in order to ascertain the possibility of obtaining these two desired results from a single two-minute test. Different steel media samples were tested at different energy levels, and finally by testing under wet and dry conditions. Dry and wet testing did not generate the same wear results. Wear and breakage rates were higher under wet conditions. In general, the size distribution of the abrasive feed evolved into a product with a finer size distribution. Statistical analysis of the data obtained suggests that there is indeed a linear relationship between the energy input into the system and the resultant Work Index value. These results support the suggestion that this test will be able to recreate the Bond Work Indices for minerals; however, more work is required in order to build a working database and determine appropriate correlation factors.L'usure des composants ferriques dans les procédés minéralurgiques et un sujet bien étudié. Le laboratoire « Comminution Dynamics » a McGill à crée un modèle nommé « Total Media Wear Model » pour prédire le temps de l'avance nécessaire avant lequel il faudra remplacer les blindages et boulettes. Cette modèle comprend des simulations informatiques et des tests de laboratoire. Une autre mesure utilisée par les contremaitres et operateurs c'est le « Bond Work Index ». L'index donne une valeur approximative pour prédire la consommation d'énergie des moulins. Un test du style « Bond » exige beaucoup d'effort, et temps. Récemment, il a été suggérer qu'on pouvait obtenir des valeurs pour le « Bond Work Index » en utilisant un procédé modifié pour un des tests du « Total Media Wear Model ». Différentes nuances d'acier on été testé avec des niveaux d'énergie variées et sous des conditions sec et humide. Les résultats on démontré que les tests sec/humides n'était pas nécessairement équivalent, de plus, un changement dans la distribution granulométrique s'est produit entre la charge et le produit. Et finalement, l'analyse des données suggère qu'il y a une relation entre la valeur calculée de « Work Index » et l'énergie introduit dans la système. Ces résultats confirment les croyances qu'on pourra déterminer la valeur de « Bond Work Index » en même temps que les données du « Total Media Wear Model ». Cependant, il faudra des tests supplémentaires pour plusieurs types de minéraux. Cela pourra crée une base de données avec lequel des facteurs de corrélations pourront être déterminer.
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Antunes, Thiago Alves. "Modelagem hidrológica da bacia hidrográfica do Alto Canoas através do modelo SWAT." Universidade do Estado de Santa Catarina, 2015. http://tede.udesc.br/handle/handle/1952.
Анотація:
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Previous issue date: 2015-02-20The Rio Canoas basin demands studies that seek the management of their hydrological resources. The hydrological modeling is promising as helper of construction process of its basin plan, because produce formal representation of reality. SWAT (Soil Water Assessment Tool) is a hydrological model able to predict runoffs by a complex group of inputs and by a significant group of calibrated parameters. In this study, SWAT was calibrated and validated in a watershed of 1973 Km² of Rio Canoas, called Alto Canoas basin. Parameters were calibrated by semiautomatic process as to daily scale as to monthly scale. The quality of the calibration and validation was evaluated by their Nash-Sutcliffe (NSE) and R² coefficients. The model was applied in the estimative of permanence curves, in the estimative of basic runoffs separated by numeric filter and in scenarios of possible hydrological impacts caused due to land use changes. It took two years to model calibration (1996-1997), where the year 1995 was used as warm up period of the model, and four years to validation (1998-2001). The model was validated in daily scale with a NSE of 0,76 and R² of 0,79. In monthly scale, the model was validate with a NSE of 0,87 and R² of 0,89. The hydrological balance by the model indicates that in the studied basin has a significant contribution of the lateral and return flow in the formation of total runoff in the reaches. The model parameters differ as in daily scale as in monthly scale, it indicate that have different relevance of some hydrological processes according to variation of time scale. The model shows as satisfactory in the simulation of daily and monthly events. This study concludes that the calibrated model can be used as to analyze daily and monthly events, by climatological data. The attachment of hydrological model with the climatological shows as a promising way as tool to be applied in hydrological resources management of Alto Canoas basin
A bacia hidrográfica do Rio Canoas demanda estudos que visem à gestão de seus recursos hídricos. A modelagem hidrológica se mostra promissora como auxiliar no processo de construção de seu plano de bacia, uma vez que produz representações formais da realidade. O SWAT (Soil Water Assessment Tool) é um modelo hidrológico capaz de simular vazões a partir de um conjunto complexo de dados de entrada e de um conjunto significativo de parâmetros calibrados. No presente estudo, o modelo SWAT foi calibrado e validado em uma sub-bacia de 1973 Km² da bacia do Rio Canoas, denominada bacia do Alto Canoas. Os parâmetros foram calibrados por processo semi-automático tanto para escala diária como mensal. A qualidade da calibração e da validação foi avaliada com base nos coeficientes de Nash-Sutcliffe (NSE) e R². O modelo foi aplicado na estimativa da curva de permanência, na estimativa das vazões básicas separadas por filtro numérico e em cenários de possíveis impactos hidrológicos provocados por mudanças no uso do solo. Foram utilizados dois anos para calibração do modelo (1996-1997), sendo o ano de 1995 utilizado como período de aquecimento do modelo, e quatro anos para validação (1998-2001). O modelo foi validado na escala diária com NSE de 0,76 e R² de 0,79. Na escala mensal, o modelo foi validado com um NSE de 0,87 e R² de 0,89. O balanço hídrico calculado pelo modelo indicou que na bacia estudada ocorre contribuição significativa do escoamento sub-superficial e básico na formação das vazões nos canais. Os parâmetros do modelo diferiram tanto na escala diária como na escala mensal, indicando haver relevâncias distintas de determinados processos hidrológicos conforme a variação da escala temporal. O modelo mostrou-se satisfatório tanto na simulação de eventos diários como mensais. Concluiu-se que o modelo calibrado pode ser utilizado tanto na análise de eventos diários como mensais, a partir de dados climatológicos. O acoplamento de modelo hidrológico com climatológico mostra-se um caminho promissor como ferramenta a ser aplicada na gestão dos recursos hídricos da bacia do Alto Canoas
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Sexton, Aisha M. "Evaluation of SWAT model applicability for waterbody impairment Identification and TMDL analysis." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7630.
Анотація:
Thesis (Ph. D.) -- University of Maryland, College Park, 2007.Thesis research directed by: Fischell Dept. of Bioengineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Queiroz, Mônica Rodrigues de. "A variabilidade climática e as mudanças de uso da terra: um estudo de caso da vazão e sedimentos da bacia do rio Piracicaba com modelagem numérica." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/91/91131/tde-12082014-173458/.
Анотація:
O objetivo desta tese foi avaliar os impactos decorrentes das mudanças de uso da terra e da variabilidade climática nos recursos hídricos (vazão e fluxo de sedimentos), em mesoescala (bacia do rio Piracicaba) e em pequena escala (microbacia do Ribeirão das Posses), através de um estudo de modelagem numérica com o modelo SWAT (Soil and Water Assessment Tool). Foram utilizados dados de modelo numérico de terreno, mapas de solo e uso da terra, temperatura, precipitação, vento, radiação solar e umidade relativa para forçar o modelo SWAT. O modelo mostrou resultados satisfatórios de desempenho na comparação com dados observados, conforme mostram os índices estatísticos na bacia do rio Piracicaba (COE entre 0,97 e 0,99 para vazão e de 0,90 para fluxo de sedimentos) e no Ribeirão das Posses (COE de 0,53 para a vazão e 0,7 para fluxo de sedimentos). Nas simulações de modificações de uso da terra os resultados indicam que em ambas as bacias as maiores vazões ocorrem nos cenários de desflorestamento, sendo o cenário de pastagem o de valores mais expressivos. O modelo correspondeu às evidências de que as vazões máximas, por exemplo os eventos de inundações, podem ser mitigados com o reflorestamento e que o cenário de antropização com gramíneas, no caso das pastagens e cana-de-açúcar, os eventos extremos tendem a ser aumentados ainda mais. Na avaliação da simulação dos fluxos de sedimentos, o cenário de reflorestamento por eucalipto mostra redução na perda do solo, porém ainda abaixo do cenário de reflorestamento por vegetação nativa, que apresentou os menores valores de fluxo de sedimentos, em ambas as bacias. Na simulação levando-se em consideração as mudanças climáticas, os resultados mostram aumento de vazão para o futuro (2078-2098) e consequente aumento de fluxo de sedimento, sendo um aumento médio de 12 % nas vazões do Piracicaba e de 19 % no fluxo de sedimentos. No Ribeirão das Posses este padrão de resposta também ocorreu, com aumento de 46% na vazão e 40 % no fluxo de sedimentos.The aim of this thesis was to evaluate the impacts of changes in land use and climate variability on water resources (discharge and sediment fluxes), into mesoscale (Piracicaba River basin) and small-scale (watershed Ribeirão das Posses) processes throughout a study of numerical modeling with SWAT model (Soil and Water Assessment Tool). Data of numerical model of terrain, soil maps and land use, temperature, precipitation, wind speed, solar radiation and relative humidity forced the SWAT model. The model showed a satisfactory performance in comparison with the observed data, as showed by the statistical indices of the Piracicaba River Basin (COE between 0.97 and 0.99 to 0.90 for flow and sediment fluxes) and Ribeirão das Posses (COE of 0.53 to 0.7 for flow and sediment fluxes). In simulations of changes in land use the results indicate that in both basins larger flows occur in the case of deforestation scenarios, being the scene of the pasture the highest values. The model corresponded to the evidence that peak flows, for example the events of flooding can be mitigated with reforestation and the scenario of anthropogenic with grasses for grazing land and sugar cane, extreme events tend to be further enhanced too. In assessing the simulation of sediment flows, the scenario of reforestation with eucalyptus shows reduction in soil loss, but still below the scenario reforestation with native vegetation, which presented the lowest values of sediment flux in both basins. In the simulation taking into account climate change, the results show increased flow to the future (2078-2098) and consequent increase in stream sediment, with an average 12% increase in the flows of Piracicaba and 19 % in the flow sediment. In Ribeirão das Posses this response pattern also occurred with a 46% increase in throughput and 40 % in the stream sediments.
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Olivieri, Luca Maria [Verfasser]. "Painted rock shelters of the Swat-Malakand area from Bronze Age to Buddhism : Materials for a tentative reconstruction of the religious and cultural stratigraphy of ancient Swat / Luca Maria Olivieri." Berlin : Freie Universität Berlin, 2013. http://d-nb.info/1032899131/34.
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Dubsky, Barbra K. "U.S. and Australian mine warfare sonar performance assessment using SWAT and Hodgson Models." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA384644.
Анотація:
Thesis (M.S. in Physical Oceanography) Naval Postgraduate School, Sept. 2000.Thesis advisor(s): Bourke, Robert H.; Wilson, James H. Includes bibliographical references (p. 145-155). Also available online.
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Keeler, Jason M. "The Effect of Tactical Tasks and Gear on Muscle Activation of SWAT Officers." UKnowledge, 2014. http://uknowledge.uky.edu/khp_etds/19.
Анотація:
Special Weapons and Tactics (SWAT) officers constitute a subgroup of specialized law enforcement officers that perform a variety of tactical operations while wearing approximately 40 kg of tactical gear. Lower back pain is a prevalent musculoskeletal injury suffered by SWAT officers. Tactical gear places significant stress on the lower back. Thus, it is important to quantify the effect that tactical gear has on muscle activation levels of torso musculature while performing occupational tasks. Electromyography was evaluated on 20 male subjects (age: 34.7±4.5 yr.; height: 1.79±.10 m; body mass: 91.53±17.32 kg; mass of gear: 13.82±1.90 kg) while performing four tactical tasks (standing, rifle walk, sitting, & shield walk) with and without gear. Electromyography was evaluated bilaterally on the erector spinae, rectus abdominis, and external oblique muscles. The dominant erector spinae (mean delta: +0.16%) and external oblique (mean delta: -0.124%) demonstrated significant changes in muscle activation with the addition of gear, which may indicate increased spinal compression. There were also trends of increased co-activation of core musculature with the addition of gear. The rifle walk and shield walk task mean muscle activations were significantly higher than the standing and sitting tasks. The shield walk produced the highest mean activations for each muscle. Physical training for SWAT officers should emphasize exercises that simulate task-specific movement patterns without gear to decrease the spinal compression associated with load carriage.
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Salou, Boris Idriss Gervais. "Estimation des apports au lac Saint-Charles à l'aide du modèle hydrologique SWAT." Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/25970/25970.pdf.
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Bossis, Ryan Christopher. "Application of the SWAT Model to Bacterial Loading rates in Kranji Catchment, Singapore." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66825.
Анотація:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 89-92).
Despite its tropical climate and abundant rainfall, Singapore is classified as a water scarce country. To protect its limited freshwater resources for both consumption and recreation, Singapore's Public Utilities Board (PUB) has created the Active, Beautiful, and Clean (ABC) campaign. In light of this program, the Massachusetts Institute of Technology (MIT) and Nanyang Technological University (NTU) in Singapore have partnered for various water quality research projects, including sampling of Choa Chu Kang, Bras Basah, Verde, and agricultural areas throughout Kranji Catchment in January 2011. Currently, bacterial levels in Kranji Reservoir are measured by sampling, which is labor intensive and delayed. As an alternative, a model of the surrounding watershed was constructed to estimate bacterial loading to the reservoir as driven by changing weather conditions. The watershed stream network was recreated using ArcSWAT, a version of the Soil and Water Assessment Tool used with geographic information system software. This model is based on a model previously created by Granger (2010). A major improvement is the specification of bacterial loading rates by land use and agriculture type. In order to estimate land-use-specific loading rates, numerous field samples were collected and analyzed for bacterial concentration in January 2011. Nonpoint source bacteria concentrations were estimated from field sample concentrations and applied to the land continuously in the model. Using weather data from January 2005 to February 2007, the model was run twice on a daily time step. The first run included only nonpoint sources, while the second included 23 sewage treatment plant point sources throughout the catchment. Simulated results were compared to independent samples taken in 2009 by Nshimyimana (2010) and indicate a general agreement of order of magnitude, with most measured values within the predicted range. The magnitudes of the nonpoint source run achieved a better fit with field data, although the point source run produced concentration frequency distributions that are approximately lognormal, a characteristic typical of environmental bacteria concentration distributions.
by Ryan Christopher Bossis.
M.Eng.
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NUNES, Francisco Miquéias Sousa. "Avaliação hidrossedimentologica de uma Bacia sem dados de vazão utilizando o modelo SWAT." Universidade Federal de Campina Grande, 2018. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/382.
Анотація:
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Capes
O crescimento populacional desordenado juntamente com a intensificação das atividades humanas estão acelerando as modificações dos ecossistemas naturais acarretando vários problemas ambientais, em particular , aos recursos hídricos. A necessidade da humanidade por esse recurso vem crescendo de forma rápida e incompatível com a capacidade de recuperação da natureza, causando a escassez e prejuízo na sua qualidade. Além disso, as diversas finalidades para as quais esses recursos são utilizados têm gerado um grande número de conflitos do uso e também degradação qualitativa e quantitativa dos corpos hídricos.No semiárido brasileiro, a situação de escassez hídrica compromete o desenvolvimento econômico e social da região. Assim, torna-se necessário desenvolver ferramentas adequadas para apoiar a tomada de decisão quanto ao uso dos recursos hídricos. Alterações no uso e na ocupação do solo afetam o comportamento do escoamento superficial, e a análise das tendências na vazão dos cursos d’água é importante para o planejamento do uso dos recursos hídricos e do solo. As variações no regime pluviométrico devido às mudanças climáticas também afetam a disponibilidade hídrica nas bacias hidrográficas.Este trabalho tem por objetivomodelar os processos de geração de escoamento superficial, erosão do solo e a recarga potencial subterrânea na bacia do Rio Sucuru a jusante da barragem de Sumé-PB utilizando o modelo SWAT. Foram utilizados dados de precipitação, temperatura, do período de 1994 a 2015, além de mapas de tipos de solo, uso e ocupação do solo com as mudanças observadas no período.Os parâmetros CANMAX, GWQMN, GW_REVAP, ESCO, EPCO e CN foram identificados como os mais influentes sobre o processo de geração de escoamento superficial. O valor do parâmetro GWQMN foi fixado em 2000 mm, pois nenhuma sondagem realizada na bacia indica uma profundidade do solo maior que 2,0 m. Os parâmetros CANMX, ESCO, EPCO e CN se mostraram muito influentes, pois qualquer pequena alteração para mais ou para menos, provocava uma superestimação e/ou subestimação da lâmina escoada, necessitando assim de muitas tentativas antes de obter seus valores finais. Os resultados demosntram a eficiência do modelo SWAT em quantificar e avaliar comparativamente os processos hidrossedimentologicos na região do cariri paraibano. A contribuição deste trabalho se dá pela formulação de uma metodologia para a realização de estudos hidrossedimentologicos em regiões onde não existem dados de escoamento superficial ou de produção de sedimento pela erosão.
Disorganized population growth coupled with the intensification of human activities is accelerating changes in natural ecosystems, leading to a number of environmental problems, in particular water resources. The need of mankind for this resource has been growing rapidly and incompatible with nature's capacity for recovery, causing scarcity and damage in its quality. In addition, the various purposes for which these resources are used have generated a large number of use conflicts and also qualitative and quantitative degradation of water bodies. In the Brazilian semi-arid, the situation of water scarcity compromises the economic and social development of the region. Thus, it is necessary to develop adequate tools to support the decision making regarding the use of water resources. Changes in soil use and occupation affect the behavior of surface runoff, and the analysis of trends in water flow is important for planning the use of water resources and soil. Variations in pluviometric regime due to climate change also affect water availability in river basins. This work aims to model the processes of generation of runoff, soil erosion and potential underground recharge in the Sucuru River basin downstream of the Sumé-PB dam using the SWAT model. Precipitation and temperature data were used from 1994 to 2015, as well as maps of soil types, land use and occupation with changes observed in the period. The parameters CANMAX, GWQMN, GW_REVAP, ESCO, EPCO and CN were identified as the most influential on the process of generation of surface runoff. The value of the GWQMN parameter was set at 2000 mm, since no survey conducted in the basin indicates a soil depth greater than 2.0 m. The parameters CANMX, ESCO, EPCO and CN were very influential, because any small changes for more or less, caused an overestimation and / or underestimation of the drained sheet, thus requiring many attempts before obtaining their final values. The results demonstrate the efficiency of the SWAT model in quantifying and comparing the hydrosedimentological processes in the Paraíba region. The contribution of this work is given by the formulation of a methodology for the realization of hydrosedimentological studies in regions where there is no data of surface runoff or sediment production.
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VEIGA, Aldrei Marucci. "Calibração do modelo hidrossedimentológico SWAT na bacia hidrográfica do Córrego Samambaia, Goiânia - GO." reponame:Repositório Institucional da CPRM, 2014. http://rigeo.cprm.gov.br/xmlui/handle/doc/1766.
Анотація:
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A produção de sedimentos caracteriza-se como uma das importantes variáveis que precisam ser determinadas em bacias hidrográficas. Para um efetivo controle de erosão, é necessário avaliar os fatores que interagem na degradação do solo e da água. Na hidrologia, o entendimento do balanço hídrico é de suma importância uma vez que é a força primária que controla a dinâmica do transporte de sedimentos e nutrientes. O objetivo deste trabalho é realizar análises de calibrações do modelo hidrossedimentológico Soil Water Assessment Tool (SWAT) em termos de vazão e sedimento em suspensão na Bacia Hidrográfica do Córrego Samambaia para estimar a produção de sedimento na bacia. Foram realizadas medições de vazões e sedimentos em suspensão durante o período de Fevereiro a Dezembro de 2013 e os dados climáticos foram obtidos da estação meteorológica localizada na Escola de Agronomia da UFG. Os dados do terreno tais como o Modelo Digital de Elevação (MDE), tipos de solo e uso e ocupação do solo foram adquiridos no site do Sistema de Informação e Estatística de Goiás (SIEG). A análise estatística pelo Coeficiente de Eficiência de Nash-Sutcliffe – COE, resultou em 0,80 e 0,88 para o escoamento superficial e sedimento em suspensão, respectivamente, sendo considerados bons ajustes entre os valores medidos e simulados. Após a calibração pode-se verificar que a maior parte da produção de sedimento está nas sub-bacias próximas ao exutório da bacia do Córrego Samambaia, e observa-se que onde há glebas com vegetação remanescente ocorre redução de sedimento, e o contrário acontece nas áreas com predominância de urbanização e pastagem. As análises de calibração foram realizadas no próprio software SWAT (interface ArcSwat) e no software SWAT-CUP, que é uma ferramenta específica para calibração automática. Inicialmente, a simulação no SWAT apresentou valores superestimados nos picos de escoamento superficial e subestimou as vazões mínimas. Entretanto, e após a análise de sensibilidade, os picos foram minimizados e as vazões mínimas apresentaram valores mais ajustados aos valores medidos. No SWAT-CUP foram utilizadas as técnicas de GLUE, PARASOL e SUFI-2, sendo que o último apresentou melhor ajuste aos valores medidos. O parâmetro Cn2 (CN do método de curva número do SCS) foi o que apresentou maior sensibilidade na calibração e está relacionado ao tipo de solo, uso e cobertura do solo de acordo com a taxa de infiltração, textura e estrutura. Posterior ao parâmetro Cn2, o fator alfa do fluxo de base foi outro que apresentou maior sensibilidade. O elevado valor obtido para o coeficiente de Manning permite que o escoamento superficial seja amortecido. Assim, e levando em consideração as três variáveis de decisão mais sensíveis para descarga líquida, os resultados do modelo evidenciaram as características físicas do solo, tanto para o CN quanto para o retorno do fluxo de base, e a cobertura deste pela restrição à velocidade do escoamento através do elevado coeficiente de rugosidade obtido nas simulações.
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Malutta, Simone. "Estudo hidrossedimentológico da bacia hidrográfica do Rio Negrinho - SC com o modelo SWAT." Florianópolis, SC, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/96212.
Анотація:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia AmbientalMade available in DSpace on 2012-10-26T09:52:07Z (GMT). No. of bitstreams: 1 302405.pdf: 2070639 bytes, checksum: af3c0dbdb11149c06a20688421b73f85 (MD5)
O município de Rio Negrinho vem sofrendo com alteração da quantidade e qualidade da água devido a substituição da mata nativa por reflorestamento de pinus e acelerada urbanização. Visto isso, o presente estudo teve como objetivo analisar espacialmente os processos hidrossedimentológicos na bacia do Rio Negrinho - SC através do modelo SWAT. Foram realizado o monitoramento hidrossedimentológico, formação de banco de dados espaciais e tabulares, determinação das sub-bacias, calibração e validação do modelo, análises estatísticas, avaliação espacial da produção de água e de sedimentos e verificação da tolerância de perda de solos nas sub-bacias. Os dados simulados pelo modelo foram comparados com os dados observados de vazão em dois pontos de monitoramento da bacia e os dados de concentração de sedimento em um ponto da bacia. O desempenho do modelo foi analisado a partir do NASH (coeficiente de Nash-Sutcliffe), R2 (coeficiente de correlação), Erro médio (EM) e CMR (Coeficiente de massa residual). Os valores de NASH variaram de 0,48 a 0,61 para dados de vazão e 0,43 para dados de sedimento. Analisando o balanço hídrico da bacia o coeficiente de variação da precipitação, vazão e evapotranspiração mensal foi de 23%, 20% e 30% respectivamente. Já o armazenamento de água no solo variou muito pouco ao longo do ano, apresentando coeficiente de variação de 8,7%. Comparada a tolerância de perda de solos com os dados de produção de sedimento da bacia foi possível evidenciar que 11% da área da bacia apresentaram produção de sedimento maior que a tolerância.
The Rio Negrinho city has been suffering from the quantitative and qualitative modification of water due to replacement of native forests by pine tree reforestation and accelerated urbanization. The objective of the present study was, therefore, to spatially analyze hydrosedimentological processes in the Negrinho river basin # SC through the SWAT model. Hydrosedimentological monitoring, construction of spatial databases and table, determination of sub-basins, the model calibration and validation, statistical analysis, spatial assessment of water and sediment yield and verification of soil loss tolerance in each sub-basin were carried out. The values simulated with the model were compared with the observed data of discharge at two monitoration points and of sediment concentration at one point in the basin. The model performance was evaluated with the coefficient of Nash-Sutcliffe (NASH), the correlation coefficient (R2), the average error (MS) and coefficient of residual mass (CRM). The NASH values were from 0.48 to 0.61 for the discharge data and 0.43 for the sediment data. Analyzing the water balance of the basin the coefficient of variation of the monthly precipitation, evapotranspiration and flow were 23%, 20% and 30%, respectively. The water storage in the soil varied little throughout the year, showing its coefficient of variation of 8.7%. Comparing to soil loss tolerance with the sediment production data, it was shown that 11% of the basin area would have more sediment production than the tolerated value.
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Brighenti, Tássia Mattos. "Modelagem hidrológica e avaliação de diferentes métodos de calibração para o modelo SWAT." reponame:Repositório Institucional da UFSC, 2015. https://repositorio.ufsc.br/xmlui/handle/123456789/136347.
Анотація:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Ambiental, Florianópolis, 2015.Made available in DSpace on 2015-11-10T03:09:43Z (GMT). No. of bitstreams: 1 335886.pdf: 3259319 bytes, checksum: 9cb8269db77dc537fdb593274cea07a9 (MD5) Previous issue date: 2015
Um dos principais desafios enfrentados pela modelagem hidrológica é a calibração eficiente dos parâmetros do modelo. O objetivo deste estudo foi testar métodos de calibração hierárquicos para o modelo Soil and Water Assessment Tool (SWAT) considerando variações da bacia. A área de estudo foi a bacia hidrográfica do Rio Negrinho, localizada no estado de Santa Catarina, com uma área de 198,5 km². Antes da primeira simulação os dados de entrada foram pré-processados: os dados de chuva (1999-2012) foram interpolados pelo método da Krigagem Simples com Diferentes Médias Locais e Elevação como Variável Externa, e um filtro automático foi usado para separar o escoamento superficial e de base a partir da vazão medida. Uma análise de sensibilidade dos parâmetros foi realizada e do total, 15 parâmetros foram selecionados. A calibração do modelo foi feita usando o algoritmo Sequential Uncertainty Fitting (SUFI2), utilizando testes de crescente complexidade. A série de vazões observadas foi dividida em períodos distintos de calibração e validação (Split Sample Test) sendo que os resultados obtidos para o intervalo mensal foram considerados aceitáveis com um coeficiente de Nash?Sutcliffe (NSE) =0,5 e Pbias=±25%. Na análise de cada ano separadamente (Differential Split-Sample Test) a calibração e validação dos anos úmidos (2008 a 2012) foi mais eficiente que dos anos secos (2003 a 2007). No processo de validação do modelo para uma bacia com uso do solo semelhante (Proxy-Catchment Test), o modelo não foi eficiente para o ajuste dos picos de vazões (NSE de 0), porém, houve uma compensação dos volumes na estimativa do balanço hídrico (Pbias de 0,1%). Os resultados indicam que a eficiência do modelo SWAT depende da quantidade de dados disponíveis e do período de calibração. Para simulação de cenários climáticos e de mudanças de uso do solo o modelo deve ser calibrado e validado usando dados espacialmente bem distribuídos e uma série de vazões suficientemente representativa que considere períodos secos e úmidos.
Abstract : One of the main challenges facing hydrological modeling is the effective calibration of model parameters. The aim of this study was exemplified a calibration scheme for the Soil and Water Assessment Tool (SWAT) model by considering land use and climate changes. The study area was the Rio Negrinho watershed (198,5 km²), located in Santa Catarina State, Brazil. Before the first simulation, input data were preprocessed: rainfall data (1999 to 2012) were interpolated using Simple Kriging with Varying Local Means with Elevation as External variable, and an automated digital filter technique was used to separate baseflow from the measured streamflow. A parameter sensitivity analysis was carried out and 15 parameters were selected. Model calibration was performed with the Sequential Uncertainty Fitting (SUFI2) Algorithm through increasing complexity tests. The measured flow series was first divided into calibration and validation periods(Split Sample Test) wherein the predicted monthly flow matched the measured values, with a Nash?Sutcliffe coefficient (NSE) =0.5 and Pbias<±25%. When wet and dry periods were considered separately (Differential Split-Sample Test) the NSE values of wet years (2008 a 2012) were higher than dry years values (2003 a 2007). In the SWAT validation for a watershed with similar land use (Proxy-Catchment Test), the model could not capture the flow peaks well (NSE of 0), however, the water balance volumes were compensated (Pbias of 0.1%). The case study demonstrates that SWAT performance vary largely, depending on the spatial scale and calibration period. SWAT model can be used in further studies to simulate land use and climate change scenarios however it must be calibrated and validated using data spatially well distributed and recorded series segment including dry and wet periods.
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Franco, Ana Clara Lazzari. "Calibração do modelo SWAT com evapotranspiração proveniente de sensoriamento remoto e vazão observada." reponame:Repositório Institucional da UFSC, 2017. https://repositorio.ufsc.br/xmlui/handle/123456789/176915.
Анотація:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Ambiental, Florianópolis, 2017.Made available in DSpace on 2017-07-04T04:04:06Z (GMT). No. of bitstreams: 1 346685.pdf: 5170246 bytes, checksum: efa1a19bd4cbb2eb8201c13c5bb9af28 (MD5) Previous issue date: 2017
Recentemente o uso de modelos hidrológicos distribuídos e semi-distribuídos tem crescido, principalmente devido ao aumento na capacidade de processamento computacional e da disponibilidade de dados espacialmente distribuídos. Sua aplicação na gestão de recursos hídricos, como importante ferramenta de apoio nas tomadas de decisão, requer que as incertezas envolvidas nas estimativas modeladas sejam sempre quantificadas e comunicadas aos seus usuários. Apesar de indissociável, essas incertezas nem sempre são apresentadas nos estudos relacionados. A calibração de modelos hidrológicos utilizando variáveis observadas de maneira espacialmente distribuída, ou diferentes variáveis, pode ser capaz de reduzir as incertezas e contornar o problema da equifinalidade, pois menos conjuntos de parâmetros são capazes de satisfazer os critérios de calibração em todas as áreas simultaneamente. O presente trabalho procura investigar as hipóteses de que as calibrações multi-site e multi-variável são capazes de melhorar o desempenho e diminuir as incertezas da simulação de vazão pelo modelo SWAT. Foram avaliadas diferentes estratégias de calibração, integrando o uso de medições de vazão em múltiplas estações fluviométricas e estimativas de evapotranspiração provenientes de sensoriamento remoto. O modelo foi calibrado e validado na bacia hidrográfica do rio Iguaçu, pelo SUFI-2, utilizando como função objetivo o índice KGE (Kling-Gupta Efficiency). A transferência de parâmetros entre diferentes escalas temporais também foi investigada. Para isto, os parâmetros foram calibrados em escala mensal e validados nas escalas mensal e diária. A evapotranspiração real foi obtida dos resultados da aplicação do METRIC a imagens MODIS por Uda (2016), que produziu estimativas mensais para toda a bacia do rio Iguaçu. Os resultados indicam que a adição de múltiplas estações fluviométricas e/ou da evapotranspiração nas estratégias de calibração leva à diminuição das incertezas na simulação da vazão. Todavia, as calibrações multi-site e multi-variável não levaram a melhorias significativas na performance do modelo na simulação da vazão. As validações em escala diária apresentaram resultados razoáveis em relação às incertezas (fator-p e fator-r) e à função objetivo (KGE>=0,50) para a simulação de vazão. Entretanto, o exutório e algumas subbacias não foram capazes de simular os picos de vazão satisfatoriamente. A transferência de parâmetros entre escalas temporais no SWAT depende de mais estudos.
Abstract : Distributed hydrological models use has recently grown mostly due to the rising computational processing capacity and data availability. Application of hydrological models on water resources management, as important tool for decision making, requires the prediction uncertainty to be evaluated and clearly communicated to users. Despite intrinsic, uncertainty is not always clearly related. The use of multi-variable and/or multi-site calibration on hydrologic distributed models can help reduce equifinality problems, since less parameter sets can satisfy calibration criteria at all sites simultaneously. The present study investigate the hypothesis that multi-site and/or multi-variable calibration are able to improve model performance and reduce prediction uncertainty for streamflow predictions on SWAT model. Different calibration strategies were evaluated, integrating multiple streamflow measurements and evapotranspiration estimates from remote sensing products. SWAT model was calibrated and validated on Iguaçu river basin, using SUFI-2, with Kling-Gupta Efficiency (KGE) as objective function. The transference of parameters among different time steps was also investigated. For that, the model was calibrated only at monthly time step and validated on monthly and daily time steps. Actual evapotranspiration estimates were obtained from Uda (2016), which produced monthly evapotranspiration maps for the entire Iguaçu river basin. Results indicate that the use of multi-site or multi-variable calibration reduces streamflow prediction uncertainty, but no significant performance improvement was observed. Model daily validation results were satisfactory regarding uncertainty (r-factor and p-factor) and the objective function (KGE>=0,50) for the streamflow simulation. On the other hand, the main outlet and some subbasins were unable to correctly simulate flow peaks. Parameter transference between temporal scales for SWAT requires further investigation.
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Corpas, Pedro. "Stress and Coping Abilities of SWAT Personnel in a Metropolitan Area of Florida." ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/5065.
Анотація:
For decades, stress has been scientifically studied and found to have effects on the law enforcement community. Furthermore, scholars have thoroughly studied the correlation between stress and the law enforcement occupation which has been proven to affect their well-being. Although there is currently ample literature on stress and police officers, to date there has been little research on factors associated with stress and SWAT police officers. Using Lazarus and Folkman's cognitive theory of stress and coping as the foundation, the purpose of this phenomenological study was to explore how SWAT police officers cope with stress while on duty and off duty and the factors that cause them stress. Participants included 5 retired police officers who were members of a SWAT team. Moustakas' framework design of phenomenological study assisted in identifying common themes that emerged from participant interviews. Study findings indicate that the primary stressor to SWAT officers was responding to high-risk missions or operations and that law enforcement agencies generally fail to provide the resources needed to cope with stress. In addition, the main coping resources used by tactical officers were self-initiated activities such as exercise, spending time with family, and hobbies (e.g., hunting, fishing, camping, hiking, and sports entertainment). The results of this study encourage positive social change by advancing recommendations to law enforcement leadership to develop coping resources for tactical officers that are specific to their unique needs. The study also increases awareness and knowledge of the coping resources that SWAT officers need and advocating for new programs and trainings aimed at reducing stress for them, which may prevent officer burnout and improve public safety response.
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Staley, Nathan Andrew. "Modeling Channel Degradation at the Watershed Scale: A Comparison of GWLF, SWAT, and CONCEPTS." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/35267.
Анотація:
Modeling Channel Degradation at the Watershed Scale: A Comparison of GWLF, SWAT, and CONCEPTS.Author: Nathan A. Staley
In 2005 an assessment of existing Total Maximum Daily Load studies by the U.S. Environmental Protection Agency showed sediment as the fourth leading cause of water quality impairment. A source assessment is important in developing a successful TMDL. Past research efforts have focused on controlling erosion sources in agricultural and urban land areas. New research suggests major contributions to overall sediment loads may be due to stream channel degradation. Monitoring and modeling techniques to assess the contribution of channel sediment to overall sediment load are needed to determine the reductions necessary to meet water quality standards. This research focused on testing the ability of watershed and reach-scale models to predict stream channel degradation. Model predictions were compared to estimates developed from a system of erosion pins and scour chains.
A 500-m experimental reach in Blacksburg, VA, USA, was selected as the focus of channel degradation monitoring and modeling efforts. A series of over 250 erosion pins and seven scour chains were installed systematically throughout the experimental reach. A monthly monitoring program measured channel degradation for the period from July 2005 - June 2006. Point data were interpolated across individual bank segments to produce an estimate of soil erosion volume. Measured soil bulk densities were then used to calculate the estimated mass loading to Stroubles Creek from channel degradation.
Two watershed models and one reach-scale model were developed to predict sediment loading to the stream channel from channel degradation. The Generalized Watershed Loading Function (GWLF) was selected to represent watershed models with limited channel degradation process detail; the Soil and Water Assessment Tool (SWAT) represented the level of channel degradation detail seen in the majority of watershed models; and the CONservation Channel Evolution and Pollutant Transport System (CONCEPTS) reach-scale model was used to evaluate the effectiveness of a detailed process model. Monthly model predictions were compared to retreat rates measured using the erosion pin network.
Sediment loading to the stream from bank retreat was estimated as 41 tonnes/yr, based on erosion pin measurements. GWLF, SWAT, and CONCEPTS predicted stream channel sediment contributions of 8 tonnes/yr, 1500 tonnes/yr and 4 tonnes/yr, respectively. Theil-Sen non-parametric simple linear regression was used to test agreement between monthly model predictions and erosion pin estimates. No significant agreement was found between any model predictions and measured retreat, using a conservative a-value of 0.2. GWLF model predictions underpredicted measured channel degradation, but most closely approximated observed data. This result is likely due to similarities in climate and watershed characteristics for the Stroubles Creek watershed and the Pennsylvania watershed used in the empirical model development. SWAT predicted retreat rates exceeded measured values by two orders of magnitude. This result is explained by the inability of SWAT to predict daily flow and sediment discharge. Highly sensitive channel degradation parameters and the lack of calibration data also contributed to SWAT simulation error. CONCEPTS simulation predicted monthly retreat rates slightly less than GWLF. The lack of agreement between CONCEPTS simulation and observed data was mainly the result of limited input data availability. SWAT daily discharge predictions were used as CONCEPTS input data and likely contributed to poor model agreement. Poor estimation of sensitive sediment input parameters may have also contributed to underpredictions by CONCEPTS. Results showed the potential of screening-level watershed models in channel degradation prediction and the importance of flow and sediment time series discharge data in detailed process-based simulation. The limited flexibility of the GWLF channel degradation algorithm makes it unsuitable for evaluating the effects of stream restoration. SWAT and CONCEPTS should only be used for evaluation if appropriate input data are available.
Future research will focus on the development of a long-term flow and sediment monitoring data set. Few long-term data sets of this nature exist, making channel degradation modeling difficult. Development of long-term data will allow more accurate modeling and better assessment of channel restoration impacts on channel degradation. Further modeling with GWLF in geographic regions outside the Eastern United States is also needed to determine the scope of applicability of the GWLF channel degradation empirical relationship. Additional research should also focus on the significance of subaerial processes for watersheds of various sizes and on the development of algorithms to simulate these processes.
Master of Science
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Junior, Paulo Ponce Arroio. "Aprimoramento das rotinas e parâmetros dos processos hidrológicos do modelo computacional Soil and Water Assessment Tool - SWAT." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-25052017-084925/.
Анотація:
O modelo Soil and Water Assessment Tool (SWAT) tem sido utilizado para avaliar os impactos do uso e manejo da terra nos recursos hídricos, sedimentos e agroquímicos em diversas escalas e condições ambientais em todo o mundo. Entretanto, pelo fato de ter sido desenvolvido em centros de pesquisa norte-americanos, alguns parâmetros e rotinas de simulação não refletem adequadamente determinados processos de bacias localizadas em regiões tropicais. Nesse sentido, o presente trabalho visou aprimorar a modelagem hidrológica do SWAT através da revisão e modificação de processos relacionados à simulação da evapotranspiração. Os procedimentos propostos incluíram a alteração das rotinas de dormência vegetal no código fonte do modelo e a modificação dos cronogramas de operações de manejo e parâmetros do banco de dados de crescimento das plantas, visando reproduzir com maior precisão o ciclo das culturas em bacias tropicais. As modificações foram testadas em cinco bacias localizadas no Estado de São Paulo, com áreas entre 42 e 5.959 km², sendo comparados os resultados obtidos antes e depois da implementação das mesmas. Com as alterações, a análise do balanço hídrico anual evidenciou um aumento nos valores de evapotranspiração de cerca de 61% nas bacias, aproximando-se dos totais anuais de evapotranspiração calculados através de métodos empíricos, bem como houve redução significativa do escoamento superficial. Verificou-se uma melhoria da simulação de vazão em todas as bacias, sendo obtidos valores superiores para o Coeficiente de Eficiência de Nash-Sutcliffe (NSE) quando comparados à simulação sem as alterações. A calibração e validação foram realizadas com base na simulação modificada, sendo obtidos valores de NSE mensais entre 0,71 e 0,93 na calibração e 0,53 e 0,88 na validação, enquanto os valores diários de NSE situaram-se entre 0,51 e 0,82 na calibração e 0,38 e 0,83 na validação. A calibração a partir de uma simulação na qual as distorções dos processos hidrológicos da bacia estivessem previamente minimizadas resultou em bons resultados sem alteração excessiva dos parâmetros, indicando uma simulação hidrológica de melhor consistência.The Soil and Water Assessment Tool (SWAT) has been used to predict the impact of land management practices on water, sediment, and agricultural chemical yields in a wide range of scales and environmental conditions across the globe. However, originally developed in the United States, some parameters and routines are unrealistic for simulating in tropical watersheds. In this sense, this work aims to improve the hydrologic modeling of SWAT model by reviewing and modifying parameters and routines related to evapotranspiration process. In order to adequately represent crop growth in tropical basins, the proposed procedures included changes in dormancy routines of SWAT source code and modifications of scheduled management operations and plant growth database parameters. These modifications were tested in five different basins at São Paulo State, Brazil, with areas ranging from 42 to 5959 km², by comparing the results before and after their implementation. Annual water balance analysis showed an increase in evapotranspiration about 61% for basins, approaching the total annual evapotranspiration estimated by empirical methods. Hence, it was observed that surface runoff and base flow components showed a decrease. The modifications resulted in improved flow simulation for all basins, showing better Nash-Sutcliffe Efficiency Coefficient (NSE) values compared to the unchanged simulation. Calibration and validation processes used the modified simulation database, being achieved monthly NSE between 0.71 – 0.73 at calibration and 0.53 – 0.88 at validation, while daily NSE were 0.51 – 0.82 at calibration and 0.38 – 0.83 at validation. Overall, minimizing distortions in hydrological processes at pre-calibration step resulted in good estimations without excessive modification of parameters at calibration, attesting a consistent hydrological modeling for the basins analyzed.
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Junior, Paulo Ponce Arroio. "Avaliação da produção e transporte de sedimentos na bacia hidrográfica do Rio Itaqueri, municípios de Itirapina e Brotas - SP." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-02052013-083541/.
Анотація:
Os processos de erosão e produção de sedimentos constituem eventos de grande relevância na atualidade, ocorrendo em escala global e ocasionando prejuízos nas esferas ambiental, econômica e social. Diversas pesquisas concentram seus esforços no sentido de entender as variáveis e os condicionantes destes fenômenos, os quais vêm sendo compreendidos por meio da multidisciplinaridade de diversas áreas do conhecimento. Nesse contexto, o presente estudo teve como objetivo realizar um diagnóstico da produção de sedimentos e de seu transporte na bacia hidrográfica do Rio Itaqueri, localizada nos municípios de Itirapina e Brotas - SP, na qual está inserido o Reservatório do Lobo ou do Broa. Dentre os elementos de análise, foi utilizado o simulador hidrossedimentológico SWAT para estimar a produção de sedimentos na bacia, bem como foi realizado o monitoramento da qualidade da água, a quantificação da carga sólida em suspensão e a determinação da granulometria do material de leito em seções de amostragem localizadas nos principais tributários do reservatório. Por meio da simulação, verificou-se que ocorrem na bacia áreas com diferentes comportamentos hidrossedimentológicos, com locais onde a produção anual média de sedimentos chega a 18 t/ha e outras áreas onde esta é próxima de zero. Foi constatado que o Rio Itaqueri contribuiu com 65% do total anual médio de sedimentos que chega ao reservatório, sendo neste rio também observados os maiores valores de carga sólida em suspensão. A parte alta da bacia configurou-se como uma área de maior aporte de sedimentos na rede de drenagem, sendo os reflexos desta dinâmica observados na qualidade da água destes locais, enquanto nas áreas de médio e baixo curso evidenciou-se a predominância de processos deposicionais. Verificou-se que as análises de parâmetros de qualidade da água e de caracterização do sedimento permitiram complementar os resultados obtidos pelo SWAT, fornecendo subsídios para uma melhor compreensão da dinâmica sedimentológica da bacia.The soil erosion and the sediment yield are considered one of the biggest present environmental problems, a worldwide issue that inflicts environmental, economic and social damages. Many researches have efforts to understand the variables and constraints of these phenomenon, which have been understood through the multidisciplinarity of different areas of knowledge. In this context, this study attempts to obtain a diagnosis of sediment yield and its transport in Itaqueri River basin, in which is inserted the Lobo-Broa Reservoir. The hydrosedimentological model SWAT was used to estimate the sediment yield in the basin, as well was performed the monitoring of water quality, the quantifying of suspended-sediment discharge and the determination of bed material particle size distributions in streams. Through simulation, it was observed that occur in the basin different hydrosedimentological behaviors, where the average annual production of sediments is 18 t/ha, and its null in some places. It was observed that Itaqueri River contributed 65% of total average annual sediment reaching the reservoir, and this river also has the highest values of suspended-sediment discharge. The upper part of the basin was shown as an area of major input of sediment in drainage network, influencing the water quality in these sub-catchments, while middle course and low course of the river revealed the predominance of depositional processes. Water quality parameters and characterization of river bed sediment supplemented the results obtained by SWAT model, supporting a better understanding of hydrosedimentological processes.
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Carleto, Nivaldo [UNESP]. "Integridade de dados meteorológicos para uso em modelo hidrológico." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/139518.
Анотація:
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No Brasil, as Estações Meteorológicas Automáticas (EMA) vêm sendo utilizadas no setor agrícola, em universidades e institutos de pesquisa. Porém, é fundamental garantir a confiabilidade dos dados meteorológicos coletados pelos sensores destas estações. Diante disso, objetivou-se neste trabalho verificar a influência da integridade dos dados (velocidade do vento, radiação solar, temperatura e umidade do ar e precipitação pluviométrica) sobre os parâmetros hidrológicos da Bacia Hidrográfica do Córrego Rico/SP utilizando o modelo SWAT. Os dados foram obtidos por três estações meteorológicas automáticas; uma da Campbell Scientific e outra da Davis Instruments instaladas no Departamento de Engenharia Rural da FCAV/UNESP (Câmpus de Jaboticabal/SP) e uma outra do Sistema Integrado de Dados Ambientais (SINDA) do Instituto Nacional de Pesquisas Espaciais (INPE), localizada próxima ao Departamento de Ciências Exatas da FCAV/UNESP. Foram aplicadas técnicas para verificar a integridade dos dados destas estações e o modelo SWAT para analisar os parâmetros hidrológicos da Bacia Hidrográfica do Córrego Rico/SP. De acordo com os resultados, verificou-se que os dados dos sensores de precipitação, de velocidade do vento, de umidade relativa do ar e de radiação solar da EMA do SINDA/INPE não foram aceitáveis devido à falta de calibração, manutenção e inspeção da estação. Como consequência, houve diferenças significativas nos parâmetros hidrológicos de saída do modelo SWAT, o que compromete o planejamento e a gestão de recursos hídricos e naturais.
In Brazil, Automatic Weather Stations (EMA) have been used in the agricultural sector, universities and research institutes. However, it is essential to ensure the reliability of meteorological data collected by the sensors of these stations. The research objective of this study was to investigate the influence of data integrity (wind speed, solar radiation, temperature and humidity and precipitation) on the hydrological parameters Basin Stream Rico/SP using the SWAT model. The data were obtained for three automatic weather stations; one of Campbell Scientific and another from Davis Instruments installed in the Department of Rural Engineering FCAV/UNESP (Jaboticabal/SP Campus) and another of the Integrated Environmental Data (SINDA) of the National Institute for Space Research (INPE), located near the Department of Exact Sciences FCAV/UNESP. Techniques were applied to verify the integrity of the data from these stations and the SWAT model to analyze the hydrological parameters Basin Stream Rico/SP. According to the results, it was found that the data precipitation sensors, wind speed, relative air humidity, and solar radiation EMA SINDA/INPE were not acceptable due to lack of calibration, maintenance and inspection season. As a result, there were significant differences in the output parameters of the SWAT hydrologic model, which undertakes the planning and management of water and natural resources.
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Sun, Leqiang. "Streamflow and Soil Moisture Assimilation in the SWAT model Using the Extended Kalman Filter." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34975.
Анотація:
Numerical models often fail to accurately simulate and forecast a hydrological state in operation due to its inherent uncertainties. Data Assimilation (DA) is a promising technology that uses real-time observations to modify a model's parameters and internal variables to make it more representative of the actual state of the system it describes. In this thesis, hydrological DA is first reviewed from the perspective of its objective, scope, applications and the challenges it faces. Special attention is then given to nonlinear Kalman filters such as the Extended Kalman Filter (EKF). Based on a review of the existing studies, it is found that the potential of EKF has not been fully exploited.
The Soil and Water Assessment Tool (SWAT) is a semi-distributed rainfall-runoff model that is widely used in agricultural water management and flood forecasting. However, studies of hydrological DA that are based on distributed models are relatively rare because hydrological DA is still in its infancy, with many issues to be resolved, and linear statistical models and lumped rainfall-runoff models are often used for the sake of simplicity. This study aims to fill this gap by assimilating streamflow and surface soil moisture observations into the SWAT model to improve its state simulation and forecasting capability. Unless specifically defined, all ‘forecasts’ in Italic font are based on the assumption of a perfect knowledge of the meteorological forecast. EKF is chosen as the DA method for its solid theoretical basis and parsimonious implementation procedures.
Given the large number of parameters and storage variables in SWAT, only the watershed scale variables are included in the state vector, and the Hydrological Response Unit (HRU) scale variables are updated with the a posteriori/a priori ratio of their watershed scale counterparts. The Jacobian matrix is calculated numerically by perturbing the state variables. Two case studies are carried out with real observation data in order to verify the effectiveness of EKF assimilation. The upstream section of the Senegal River (above Bakel station) in western Africa is chosen for the streamflow assimilation, and the USDA ARS Little Washita experimental watershed is chosen to examine surface soil moisture assimilation. In the case of streamflow assimilation, a spinoff study is conducted to compare EKF state-parameter assimilation with a linear autoregressive (AR) output assimilation to improve SWAT’s flood forecasting capability. The influence of precipitation forecast uncertainty on the effectiveness of EKF assimilation is discussed in the context of surface soil moisture assimilation.
In streamflow assimilation, EKF was found to be effective mostly in the wet season due to the weak connection between runoff, soil moisture and the curve number (CN2) in dry seasons. Both soil moisture and CN2 were significantly updated in the wet season despite having opposite update patterns. The flood forecast is moderately improved for up to seven days, especially in the flood period by applying the EKF subsequent open loop (EKFsOL) scheme. The forecast is further improved with a newly designed quasi-error update scheme.
Comparison between EKF and AR output assimilation in flood forecasting reveals that while both methods can improve forecast accuracy, their performance is influenced by the hydrological regime of the particular year. EKF outperformed the AR model in dry years, while AR outperformed the EKF in wet years. Compared to AR, EKF is more robust and less sensitive to the length of the forecast lead time. A combined EKF-AR method provides satisfying results in both dry and wet years.
The assimilation of surface soil moisture is proved effective in improving the full profile soil moisture and streamflow estimate. The setting of state and observation vector has a great impact on the assimilation results. The state vector with streamflow and all-layer soil moisture outperforms other, more complicated state vectors, including those augmented with intermediate variables and model parameters. The joint assimilation of surface soil moisture and streamflow observation provides a much better estimate of soil moisture compared to assimilating the streamflow only. The updated SWAT model is sufficiently robust to issue improved forecasts of soil moisture and streamflow after the assimilation is ‘unplugged’. The error quantification is found to be critical to the performance of EKF assimilation. Nevertheless, the application of an adaptive EKF shows no advantages over using the trial and error method in determining time-invariant model errors.
The robustness of EKF assimilation is further verified by explicitly perturbing the precipitation ‘forecast’ in the EKF subsequent forecasts. The open loop model without previous EKF update is more vulnerable to erroneous precipitation estimates. Compared to streamflow forecasting, soil moisture forecasting is found to be more resilient to erroneous precipitation input.
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Yang, Yali. "Evaluating agricultural non-point source pollution using the Soil and Water Assessment Tool, SWAT." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ30044.pdf.
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Yamaguchi, Yuko. "Simulating Hydrologic Response From Arizona Ponderosa Pine Watersheds Using the Basins-Swat Modeling System." Thesis, The University of Arizona, 2004. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2004_310_sip1_w.pdf&type=application/pdf.
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Sanaullah. "The armed conflict, 2007-9, in Swat Valley, Pakistan : an exploratory analysis of violence." Thesis, University of York, 2018. http://etheses.whiterose.ac.uk/20684/.
Анотація:
This research is an exploratory investigation into the phenomenon of violence in the armed conflict 2007-9 in the Swat valley, between the Taliban and the State of Pakistan. The study aims at analysing violence committed during the conflict, its significance, and the response of the community. It explores violence and its impact in a specific context, and contributes to our conceptual understanding of violence. Because it is a sensitive topic to research and since the concept of violence is inherently complex, a qualitative methodology is adopted. Three approaches which generate three different sets of data are used for triangulation: semi-structured in-depth interviews, focus group discussions, and newspaper articles. Through thematic analysis, this research finds that violence was carried out mainly for securing control over areas and maintaining it. In so doing, the civilian population of Swat was subdued through excessive use of three types of violence, namely physical violence, psychological violence, and social violence. “Social violence” in particular, in this context, is a discovery of this research and a significant and unique contribution of the thesis. The commission of violence however had a detrimental impact on the warring parties, making them lose civilian support as a result. Local communities when faced with severe violence had to struggle for survival, a complex phenomenon comprising three types, physical, psychological, and social, paralleling the forms of violence they experienced. The people struggled hard because violence disrupted the society, affecting institutions, values, and social relations. This thesis finds that it was a unique time socially and historically in Swat where significant levels of violence disrupted the societal order. In short, the research not only explores violence in the armed conflict in Swat, but also explains the complex nature of it.
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Lubitz, Emerson, Adilson Pinheiro, and Universidade Regional de Blumenau Programa de Pós-Graduação em Engenharia Ambiental. "Avaliação da aplicação do modelo hidrológico swat à Bacia do Ribeirão Concórdia-Lontras, SC /." reponame:Biblioteca Digital de Teses e Dissertações FURB, 2009. http://www.bc.furb.br/docs/DS/2008/343628_1_1.pdf.
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SERRÃO, Edivaldo Afonso de Oliveira. "Aplicação do modelo SWAT na simulação hidrológica da bacia hidrográfica do rio Itacaiúnas-PA." Universidade Federal de Campina Grande, 2018. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1756.
Анотація:
Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-09-19T19:31:31Z
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CNPq
A bacia amazônica representa a maior extensão de florestas tropicais da Terra, exercendo significativa influência no clima local e global devido aos fluxos de energia e água na atmosfera. Exerce um papel importante no sequestro de carbono, bem como na emissão de água para a atmosfera que é fundamental na manutenção da própria floresta. Vários modelos hidrológicos têm sido aplicados para os biomas do Brasil, desde bases conceituais até a inserção dos SIG’s desenvolvendo os modelos distribuídos de base física. Dentre estes, o Soil and Water Assessment Tool – SWAT é um modelo hidrológico para grandes bacias e foi desenvolvido para simular processos que ocorrem em uma bacia hidrográfica. O objetivo desse trabalho foi utilizar o modelo SWAT para simular a vazão fluvial, alguns processos hidrológicos e risco de erosão da bacia hidrográfica do rio Itacaiúnas, sudeste do Estado do Pará, bem como sua calibração e validação do modelo para a bacia de estudo. Para isto foram necessários dados de uso e ocupação do solo, tipos de solo, declividade. Bem como dados climáticos e fluviométricos de precipitação, temperatura, vento, umidade relativa, radiação solar e vazão fluvial. Os resultados demostraram que para a análise do risco de erosão para a bacia hidrográfica do rio Itacaiúnas foi constatado que ás áreas de maior risco para erosão, foram ás regiões de maior altitude com solos de fácil degradação e com uma dinâmica de uso de solo elevada, sendo estas na jusante da bacia e na porção sul do município de Marabá. Na validação da vazão obtida através do modelo SWAT, foi observado que todos os índices estatísticos aplicados mostraram que a vazão simulada tive um bom desempenho, em relação a vazão observada na estação fluviométrica da ANA. Foi validado ainda a evapotranspiração potencial simulada pelo SWAT, a partir de outros dois métodos, Linacre e Turc e observou-se que todos os índices estatísticos aplicados a evapotranspiração simulada com SWAT tive um bom desempenho em relação aos outros dois métodos de estimar evapotranspiração. Já na comparação dos métodos de Linacre teve um menor desempenho, em relação ao método de Turc, haja visto que na estimativa feita por Turc é levado em consideração radiação solar, o que torna o método mais robusto em relação a Linacre. Logo o modelo SWAT teve um bom desempenho em simular a vazão, evapotranspiração e outros processos hidrológicos para a bacia hidrográfica do rio Itacaiúnas e pode ser uma fundamental ferramenta no monitoramento hidrológico dessa bacia, além de auxiliar os tomadores de decisões em uma boa gestão dos seus recursos.
The Amazon basin represents the largest expanse of tropical rainforests on Earth, exerting significant influence on the local and global climate due to the energy and water fluxes in the atmosphere. It plays an important role in carbon sequestration as well as in the emission of water into the atmosphere that is essential in maintaining the forest itself. Several hydrological models have been applied to the biomes of Brazil, from conceptual bases to the insertion of the GIS, developing the distributed models of physical base. Among these, the Soil and Water Assessment Tool - SWAT is a hydrological model for large basins and was developed to simulate processes that occur in a watershed. The objective of this work was to use the SWAT model to simulate river flow, some hydrological processes and risk of erosion of the Itacaiúnas river basin, southeast of the State of Pará, as well as its calibration and validation of the model for the study basin. For this, data on land use and occupation, soil types and slope were required. As well as climatic and fluviometric data of precipitation, temperature, wind, relative humidity, solar radiation and river flow. The results showed that for the analysis of the erosion risk for the Itacaiúnas river basin, it was found that the areas with the highest risk for erosion were the highest altitude areas with easily degraded soils and a high soil use dynamics, being these downstream of the basin and in the southern portion of the municipality of Marabá. In the validation of the flow obtained through the SWAT model, it was observed that all the applied statistical indices showed that the simulated flow had a good performance, in relation to the flow observed in the fluviometric station of the ANA. It was also validated the potential evapotranspiration simulated by SWAT, from two other methods, Linacre and Turc, and it was observed that all the statistical indices applied to simulated evapotranspiration with SWAT performed well in relation to the other two methods of estimating evapotranspiration. In the comparison of the methods of Linacre had a lower performance, in relation to the method of Turc, since in the estimation made by Turc is taken into consideration solar radiation, which makes the method more robust in relation to Linacre. The SWAT model performed well in simulating flow, evapotranspiration and other hydrological processes for the Itacaiúnas river basin and can be a fundamental tool in the hydrological monitoring of this basin, besides helping decision-makers in a good way. management of its resources.
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Yactayo, Guido Andres. "Modification of the SWAT Model to Simulate Hydrologic Processes in a Karst-influenced Watershed." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/34807.
Анотація:
In the United States, karst ecosystems cover approximately 20 percent of the country and karst aquifers provide 40 percent of the water used for drinking. In karst-influenced watersheds, karst features such as sinkholes and sinking streams act as rapid pathways for carrying water and pollutants into streams and groundwater. Human activities on karst landscapes can present some special problems such as alterations to hydrologic regime, contamination of groundwater, ground subsidence, and damage to cave ecosystems. Modeling a karst-influenced watershed can provide a better understanding of the interactions between surface and ground water and how water quality is affected by human activities.
Several models were evaluated to determine their ability to model both discharge and nutrient transport in karst watersheds. The Soil Water Assessment Tool (SWAT) model was found to be appropriate due to its capability to represent almost all of the hydrological processes, its user-friendliness, and its ability to generate most of the parameters from available data. Moreover, SWAT can represent nitrogen transformations and transport processes and calculate nitrogen loadings, which is critical for karst watersheds. While it has been widely used and found to be an appropriate prediction tool, it does not explicitly include the capacity to represent specific features characteristic of karst-influenced basins. Baffaut and Benson (2008) modified the SWAT 2005 code to simulate faster aquifer recharge in karst environments, and this version was further modified here in the SWAT-Karst to represent karst environments at the HRU scale. A new parameter sink allows simulating the hydrology and nitrate transport in a sinkhole representing its unique landuse and soil characteristics, and a new parameter ss partitions nitrate transported with water that is lost from sinking streams.
The SWAT-KARST model was used to simulate discharge and nitrogen loadings within the Opequon Creek karst-influenced watershed, located in the Potomac and Shenandoah River basin in Virginia and West Virginia. In the Opequon Creek watershed, SWAT-karst using the HRU to represent sinkholes had a more notable impact in the watershed hydrology than SWAT-B&B using a pond to represent sinkholes.
Results of statistical evaluation show that SWAT-karst and the Baffaut and Benson (2008) version performed better than SWAT in predicting streamflow in a karst-influenced watershed. Although SWAT-karst showed almost the same performance as SWAT-B&B, SWAT-karst model offers the flexibility to represent the unique relationship between surface and ground water in karst features in an HRU.
Using an HRU to represent sinkholes can depict the associated variability of a karst landscape. The new variables sink and ss provide a mechanism to represent the nutrient transport through sinkholes and sinking streams. Sensitivity analysis showed that SWAT-karst was sensitive to the new parameter sink which can be used for model calibration and to represent water recharge and nutrient transport to aquifers outside the watershed boundary.Master of Science
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Perry, Kimberly A. "Application of the SWAT hydrological model in a small, mountainous catchment in South Africa." Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/46217.
Анотація:
Natural water resources are globally under pressure due to increasing population numbers and associated global change drivers, such as land-use and climate change. South Africa has a semi-arid climate, with variable patterns of rainfall and is often referred to as a water scarce country. Much of South Africa’s fresh water originates in mountainous areas. It is important to correctly manage these mountainous areas and the fresh water resources they provide. Hydrological models could be a useful tool aiding water resource managers in accurately assessing and predicting hydrological processes in mountainous regions. Hydrological models can be used to predict the effect that changes in a catchment area, such as land use or climate change, will have on the associated water resources in the catchment.
The aim of this study was to determine if the SWAT hydrological model could successfully simulate runoff from a small, mountainous catchment in South Africa. The SWAT model was applied to the B73A quaternary catchment located east of the Blyde River Canyon, close to Hoedspruit. This catchment is highly mountainous in nature. Observed stream flow data was obtained from the Department of Water and Sanitation (DWS) at a stream gauge located in the catchment. This observed data was used to calibrate and validate the model, using Sequential Uncertainty Fitting (SUFI-2) in the SWAT-CUP program. Results from calibration show good agreement between observed and simulated monthly stream flow data (NSE= 0.80). The model was able to bracket 68% of observed data in a small uncertainty band (r-factor = 0.67). The model was then validated using the same observed stream flow data during a different time period. Results for validation were again adequate (NSE= 0.46). In this case the model bracketed 71% of the data in a slightly larger uncertainty band (r-factor = 1.12).
The study illustrates the potential of the SWAT hydrological model to be used in mountainous, semi-arid catchment areas in South Africa. Despite limited climate data and soil data, as well as the use of only one stream flow gauge location of observed data during calibration, which limited the incorporation of spatial variability within the catchment area into the model. Reliable rainfall data was obtained in the form of a rainfall station in the study area, highlighting the importance of this input variable in the SWAT model. Also highlighted was the need for appropriate calibration procedures to accurately represent the local characteristics of the modelled area.
It was concluded that the SWAT hydrological model was able to adequately simulate the stream flow data from the B73A quaternary catchment area. This model could be a useful tool in predicting the effect of future land use and climate change scenarios on stream flow from the B73A quaternary catchment. It could be used for water resource management in this catchment.Mini-dissertation (MSc)--University of Pretoria, 2014.
tm2015
Zoology and Entomology
MSc
Unrestricted
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Johnson, Andrew. "A Regression Metamodel To Replace SWAT In Crop Yield Prediction For Big Creek Watershed." OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1238.
Анотація:
Climate change will have a significant impact on the productivity of agricultural lands and ecosystem services in the coming decades. Variability in temperature and precipitation will alter many central U.S. watersheds. Simulation models such as the Soil and Water Assessment Tool (SWAT) offer the ability to model changes in watersheds by varying inputs. Unfortunately, SWAT requires a large number of input parameters and computation time to process the output data. Regression metamodels offer an alternative that seeks to replace the simulation model with a regression equation. This research created a linear regression metamodel to approximate SWAT in crop yield prediction. Results show that regression models can account for 45-84 percent of variance in yields for corn, soybean, alfalfa, switchgrass, and cotton in Big Creek Watershed. The coefficient of variation for each of these models ranged from 13 to 41 percent. These metamodels were able to reduce simulation time from hours to minutes. The tradeoff for utilizing metamodels is computation time versus accuracy. The results of this research indicate that the considerable reduction in computation time coupled with a moderate degree of accuracy in predicting crop yields necessitates the use of metamodels over SWAT. Regression coefficients for each metamodel can reveal how various weather and farm management techniques impact crop yields. These metamodels will be utilized by the Agent Based Model to determine how farmers will respond to future economic policies and crop prices based on a series of climate scenarios.
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Lopes, Nadia Hidemi Yano. "Análise da produção de água e sedimentos em microbacias experimentais com o modelo SWAT." Florianópolis, SC, 2008. http://repositorio.ufsc.br/xmlui/handle/123456789/91899.
Анотація:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Engenharia AmbientalMade available in DSpace on 2012-10-24T03:40:54Z (GMT). No. of bitstreams: 1 262348.pdf: 4008222 bytes, checksum: 56c6b593e955bab6d7ca240eb1811ce0 (MD5)
A produção de água e sedimentos é afetada pelas alterações nos usos e cobertura do solo. Neste contexto, o monitoramento e a modelagem fornecem suporte ao manejo hidrossedimentológico. O objetivo do trabalho foi analisar a produção de água e sedimentos em microbacias hidrográficas experimentais (duas de vegetação nativa, N1 e N2, duas de reflorestamento de pinus, P1 e P2, uma de agricultura, A, e duas mistas, M1 e M2) localizadas na região norte do Estado de Santa Catarina com o modelo SWAT. Os métodos aplicados foram monitoramento hidrológico, geração de dados matriciais e tabulares, definição das sub-bacias, calibração e validação do modelo, análises estatísticas, avaliação espacial da produção de água e sedimentos e aplicação do índice de Hack. O modelo SWAT gerou dados simulados que acompanharam os dados observados de vazão. As simulações calibradas e validadas apresentaram valores médios nas funções objetivo e nas correlações. A partir das simulações foi possível conhecer as sub-bacias que produziram maior quantidade de água e de sedimentos. A limitação do modelo SWAT para pequenas bacias foi verificada devido à perda de sensibilidade na resposta da bacia e ao grande número de parâmetros necessários para calibração. Na microbacia M2, os meses de maio, novembro e dezembro apresentaram maior produção de água (750 l/s). A produção de sedimentos foi de até 10 kg/ha·mês, exceto em duas sub-bacias (200 kg/ha·mês). Na microbacia M1, a produção de água próximo ao exutório é constante de janeiro a maio (70 a 105 l/s). A produção de sedimentos foi de até 1 kg/ha.mês, no entanto sub-bacias com agricultura apresentaram, no início do cultivo, maior contribuição de sedimentos (105 kg/ha·.mês), com o passar dos meses, a contribuição diminuiu (40 kg/ha·mês) até estabilizar com o restante da bacia. A microbacia A apresentou maior produção de água e de sedimentos. As microbacias N1 e N2 armazenaram maior quantidade de água. A microbacia P2 apresentou maior produção de sedimentos, possivelmente pela declividade do rio principal (0,86 m/m). A produção de sedimentos nas microbacias apresentou valores toleráveis à perda do solo, com exceção para uma sub-bacia na M2 para os meses de maio e outubro. Portanto, a medida de controle a ser aplicada é estabelecer e manter as áreas de preservação permanente ao longo dos cursos d'água, relacionar a agricultura com a aptidão, mercado e sustentabilidade ambiental e aprofundar a orientação sobre as práticas de conservação de vegetação, solos e água. As microbacias experimentais apresentaram baixos valores de SDR que variaram entre 0,06% e 0,40%. A diminuição do SDR com a área não foi claramente evidenciada. Comparando-se a modelagem ao índice de Hack, evidencia-se que nas microbacias M2 e M1 a produção de sedimentos está relacionada aos usos e cobertura do solo. E apenas em uma sub-bacia da microbacia M2 a produção de sedimentos está relacionada à geomorfologia.
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Almeida, Rafael Alvarenga. "Modelagem hidrológica na bacia hidrográfica do rio Mucuri com a utilização do modelo SWAT." Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/10384.
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Os recursos hídricos vem sendo ameaçados cada vez mais, basicamente em função da crescente população mundial. Dessa forma, existe uma crescente demanda de estudos relacionados aos impactos das atividades humanas nos recursos hídricos. Os modelos hidrológicos se encaixam perfeitamente nesse contexto, visto que buscam representar todo o funcionamento físico do sistema hidrológico, sendo capaz assim de simular os impactos das atividades antrópicas no ciclo hidrológico. Com base nessa premissa, avaliou-se a aplicabilidade do modelo hidrológico SWAT como ferramenta de planejamento e gestão dos recursos hídricos na bacia do rio Mucuri, bem como o levantamento das suas bases de dados. Buscou-se, neste contexto, a obtenção do melhor método de classificação do uso do solo, com a utilização do classificador supervisionado por máxima verossimilhança (maxver) através da avaliação de diferentes tamanhos das amostras de treinamento do classificador e da utilização de filtros de áreas menores que a área mínima mapeável (AMM); e estudar os impactos no regime de vazões da bacia hidrográfica do rio Mucuri em função de três diferentes cenários de alteração no uso do solo, sendo: substituição da área de agricultura geral pela cultura do eucalipto, substituição da área florestal pela cultura da cana-de-açúcar e substituição da área de pastagem por área de solo exposto. A aplicabilidade do modelo foi testada por meio da comparação entre os resultados simulados e observados para a vazão, obtidos de diversas estações distribuídas ao longo da bacia. Os resultados obtidos demonstraram que a calibração e a validação dos dados apresentaram-se classificadas como bom e satisfatório respectivamente, em uma escala diária. Dessa forma, concluiu-se que o modelo SWAT demonstrou potencial para o planejamento e gestão dos recursos hídricos na bacia do rio Mucuri, ainda se mostrou eficiente para simular o impacto dos cenários de alteração do uso do solo no regime de vazões. A substituição de agricultura por eucalipto na bacia propiciou uma diminuição nas vazões médias e mínimas de referência, e as substituições de cobertura florestal por cana-de-açúcar e de pastagem por solo exposto propiciaram um aumento nas vazões média e mínimas de referência.
Water resources have been increasingly threatened as the world population grows. Under these circumstances, there is a greater demand in studies focused on the impacts of human activities on water resources. Hydrological models fit perfectly in this context, since they can represent the entire physical operation of the water system and, hence, simulating the impacts of human activities on the hydrological cycle. Based on this premise, this thesis aims to evaluate the applicability of the hydrological model SWAT as a planning and management tool of water resources in the Mucuri River basin and data collection. In this context, we analyzed the best method of land use classification. We used the classifier supervised by maximum likelihood (Maxver), evaluating different sizes of the classifier training samples and using a filter of areas smaller than the minimum mappable area (AMM). We also studied the impacts on the watershed flow regime of the Mucuri river according to three different scenarios of land use: replacement of the general field of agriculture by eucalyptus cultivation, replacement of the forest area by the culture of sugarcane and replacement of pasture for exposed soil area. The applicability of the model was tested by comparing the simulated and observed results from several stations distributed throughout the basin. The comparison shows that the calibration and validation data are classified as good and satisfactory, respectively, on a daily scale. Thus, we concluded that the SWAT model demonstrates potential for planning and management of water resources in the river basin Mucuri. It is also efficient to simulate the impact of change scenarios of land use in flow regime. The replacement of eucalyptus for agriculture in the basin led to a decrease in the average and minimum flows of reference while the substitution of forest cover by sugarcane and pasture for soil exposed provided an increase in average and minimum flows of reference.
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FUKUNAGA, D. C. "Estimação de vazão em bacias hidrográficas do Sul do Espírito Santo usando o SWAT." Universidade Federal do Espírito Santo, 2012. http://repositorio.ufes.br/handle/10/4990.
Анотація:
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Previous issue date: 2012-08-24O aumento da atividade econômica e do número de habitantes no mundo, juntamente com o uso não sustentável dos recursos hídricos, os despejos de efluentes sem tratamento no ambiente e o manejo inadequado das bacias hidrográficas, têm contribuído para diminuição da disponibilidade de água no planeta. Apesar de ser um recurso natural renovável, a água que retorna da atmosfera não ocorre de maneira uniformemente distribuída, nem no espaço geográfico, nem no tempo, tornando a sua boa gestão essencial para diminuição das consequências desastrosas dos eventos extremos de cheia e de escassez. Mas, uma gestão exitosa requer, além de profissionais qualificados, o uso de ferramentas para suporte à tomada de decisão. Neste contexto, a utilização de modelos hidrológicos pode auxiliar no planejamento e avaliação de práticas conservacionistas de solo e água e de manejo de bacias hidrográficas. Do exposto, o presente estudo teve o objetivo de avaliar a aplicabilidade do SWAT para a estimação de vazões em bacias hidrográficas no sul do Estado do Espírito Santo. Foram estudadas: a microbacia do córrego Jaqueira (MBJ), com aproximadamente 22,6 ha, e a sub-bacia do rio Itapemirim, à montante da estação fluviométrica de Rive (BIMR), com aproximadamente 2.237 km². Devido ao alto número de falhas e ao curto período de monitoramento hidrológico, não foi possível calibrar e verificar a aplicabilidade do modelo para a MBJ. Para a BIMR, na análise das vazões médias, estimou-se 45,5 m³ s-1 antes da calibração, e 32,6 m³ s-1 após a calibração, muito próxima da vazão média monitorada de 36,9 m³ s-1. Para o período de validação, a vazão média monitorada foi 22% maior (45,0 m³ s-1), enquanto a estimada foi de 33,9 m³ s-1, permanecendo próxima da vazão média estimada calibrada. Em análise gráfica, observou-se que, antes da calibração, as vazões mínimas estimadas ficaram abaixo das observadas, porém as vazões de pico eram superestimadas. Após a calibração, as vazões mínimas tiveram melhores correlações, enquanto as vazões de pico foram subestimadas. Na análise dos índices estatísticos, o R² passou de 0,74 para 0,76 após a calibração, mas foi reduzido para 0,63 no período de validação. Para o coeficiente de Nash Sufcliffe, houve uma melhora significativa do valor após a calibração, passando de -0,38 para 0,75, permanecendo com um valor aceitável de 0,57 no período de validação. O SWAT foi capaz de simular vazões em bacias hidrográficas do Sul do Espírito Santo, desde que não houvesse muitas falhas nos dados monitorados, sendo capaz inclusive de simular dados de outros períodos para os quais os parâmetros não foram ajustados.
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Oliveira, Laís Thomazini. "Aplicação do modelo SWAT para simular vazões em uma bacia hidrográfica em Aracruz, ES." Universidade Federal do Espírito Santo, 2014. http://repositorio.ufes.br/handle/10/5030.
Анотація:
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A realização de estudos hidrológicos em bacias hidrográficas advém da necessidade de se compreender os processos que controlam o movimento da água e os impactos do uso e ocupação do solo nos recursos hídricos. A estimação desses processos e a quantificação de tais impactos tem sido realizada com base na utilização de modelos hidrológicos, principalmente naqueles computacionais. O modelo computacional SWAT (Soil and Water Assessment Tool) foi selecionado como a ferramenta básica para esse estudo em função do seu objetivo, que visa avaliar os efeitos da gestão sobre a água, sedimentos, nutrientes e pesticidas, e de estar sendo testado em diferentes países, com resultados satisfatórios. Do exposto, o presente estudo teve o objetivo de avaliar a aplicabilidade do SWAT para a estimação de vazões em uma microbacia experimental (MBE) com área de 2,84 km², no município de Aracruz, ES. O principal uso da terra na MBE consistia no cultivo de eucalipto. Os índices estatísticos calculados para a calibração e validação do SWAT foram de magnitude suficiente para qualificá-lo como adequado e satisfatório para a simulação das vazões na MBE. Complementarmente à validação do modelo SWAT, foram simulados cenários hipotéticos de alterações no uso da terra, abrangendo o cultivo do eucalipto (três manejos distintos), além da pastagem e vegetação nativa, para avaliar o comportamento hidrológico da bacia. Realizaram-se análises das vazões médias, das vazões máximas associadas a diferentes períodos de retorno e das vazões mínimas de referência. Todos os cenários evidenciaram a sensibilidade do modelo às alterações da microbacia, sendo o cenário de pastagem o que proporcionou respostas mais significativas no incremento das vazões. Os resultados encontrados indicam que o SWAT é uma importante ferramenta para simular o efeito das mudanças ambientais sobre a hidrologia de bacias hidrográficas
The realization of hydrologic studies in watersheds comes from the need to understand the processes that control the movement of water and the impacts of the land use on water resources. The estimation of these processes and quantification of such impacts has been performed based on the use of hydrologic models. The computational model SWAT (Soil and Water Assessment Tool) was selected as the basic tool for this study in function of its objective, which aims at assessing the effects of management on water, sediment, nutrients and pesticides, and because it has been tested in different parts of the world, with satisfactory results. In this context, the present study had the objective of assessing the applicability of SWAT to estimate streamflow in an experimental watershed (MBE) with an area of 2.84 km², in Aracruz, ES. The main land use in the MBE is eucalyptus. Statistical indices calculated during the calibration and validation processes indicated that SWAT was appropriate and of satisfactory performance for the simulation of streamflows in the MBE. Besides the validation of SWAT, hypothetic scenarios of land use were simulated to assess the hydrological behavior of the watershed, including three different managements of Eucalyptus, pasture and native vegetation. Analyses of the mean streamflows, the peak streamflows associated with different return periods and minimum reference streamflows were performed. All scenarios showed sensitivity of the model to changes in the land use pasture showed the most significant responses to the increase of streamflow. The results of this study indicate that SWAT is an important tool to simulate the effect of environmental change on the hydrology of watersheds.
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Fukunaga, Danilo Costa. "Estimação de vazão em bacias hidrográficas do sul do Espírito Santo usando o Swat." Universidade Federal do Espírito Santo, 2012. http://repositorio.ufes.br/handle/10/5769.
Анотація:
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Previous issue date: 2012-08-24O aumento da atividade econômica e do número de habitantes no mundo, juntamente com o uso não sustentável dos recursos hídricos, os despejos de efluentes sem tratamento no ambiente e o manejo inadequado das bacias hidrográficas, têm contribuído para diminuição da disponibilidade de água no planeta. Apesar de ser um recurso natural renovável, a água que retorna da atmosfera não ocorre de maneira uniformemente distribuída, nem no espaço geográfico, nem no tempo, tornando a sua boa gestão essencial para diminuição das consequências desastrosas dos eventos extremos de cheia e de escassez. Mas, uma gestão exitosa requer, além de profissionais qualificados, o uso de ferramentas para suporte à tomada de decisão. Neste contexto, a utilização de modelos hidrológicos pode auxiliar no planejamento e avaliação de práticas conservacionistas de solo e água e de manejo de bacias hidrográficas. Do exposto, o presente estudo teve o objetivo de avaliar a aplicabilidade do SWAT para a estimação de vazões em bacias hidrográficas no sul do Estado do Espírito Santo. Foram estudadas: a microbacia do córrego Jaqueira (MBJ), com aproximadamente 22,6 ha, e a sub-bacia do rio Itapemirim, à montante da estação fluviométrica de Rive (BIMR), com aproximadamente 2.237 km². Devido ao alto número de falhas e ao curto período de monitoramento hidrológico, não foi possível calibrar e verificar a aplicabilidade do modelo para a MBJ. Para a BIMR, na análise das vazões médias, estimou-se 45,5 m³ s-1 antes da calibração, e 32,6 m³ s-1 após a calibração, muito próxima da vazão média monitorada de 36,9 m³ s-1. Para o período de validação, a vazão média monitorada foi 22% maior (45,0 m³ s-1), enquanto a estimada foi de 33,9 m³ s-1, permanecendo próxima da vazão média estimada calibrada. Em análise gráfica, observou-se que, antes da calibração, as vazões mínimas estimadas ficaram abaixo das observadas, porém as vazões de pico eram superestimadas. Após a calibração, as vazões mínimas tiveram melhores correlações, enquanto as vazões de pico foram subestimadas. Na análise dos índices estatísticos, o R² passou de 0,74 para 0,76 após a calibração, mas foi reduzido para 0,63 no período de validação. Para o coeficiente de Nash Sufcliffe, houve uma melhora significativa do valor após a calibração, passando de -0,38 para 0,75, permanecendo com um valor aceitável de 0,57 no período de validação. O SWAT foi capaz de simular vazões em bacias hidrográficas do Sul do Espírito Santo, desde que não houvesse muitas falhas nos dados monitorados, sendo capaz inclusive de simular dados de outros períodos para os quais os parâmetros não foram ajustados
The increasing of world economic activity and the number of inhabitants, along with the unsustainable use of water resources, untreated wastewater release into the environment and inadequate watersheds management, has contributed to water availability decrease on the planet. Despite being a renewable natural resource, the water that returns from the atmosphere does not occur evenly distributed, either in geographic space or in time, making its good management essential to reduce disastrous consequences of extreme events of floods and droughts. But a successful management requires, as well as qualified professionals, the use of support decision tools. In this context, the use of hydrological models can assist in planning and assessment of conservation practices for soil and water and watershed management. In this light, the present study aimed to evaluate the SWAT capability to estimate flow in river basins in the southern of Espírito Santo state, Brazil. The Jaqueira stream watershed (MBJ), with approximately 22.6 ha, and Itapemirim river basin, upstream of the Rive fluviometric station (BIMR), with approximately 2,237 km², were studied. Due to the high number of gaps and short-term hydrological monitoring, was not possible to calibrate and verify model applicability for the MBJ. For BIMR, the analysis of the average flow rate was estimated by 45.5 m³ s-1, before calibration, and 32.6 m³ s-1 after calibration, closely to the monitored average flow, that was 36.9 m³ s-1. For the validation period, the average flow monitored was 22% higher (45.0 m³ s-1), while the estimated flow was 33.9 m³ s-1, remaining closely to the average calibrated estimated flow. In graphical analysis, it was observed that before calibration, the estimated minimum flow rates were below those observed, but the peak flows were overestimated. After calibration, the minimum flows had better correlations, while the peak flows were underestimated. In the analysis of statistical indexes, the R² increased from 0.74 to 0.76, after calibration, but was reduced to 0.63 in the validation period. For the Nash Sufcliffe coefficient, was verified a significant improvement of its value after calibration, from -0.38 to 0.75, remaining with an acceptable value in the validation period, 0.57. The SWAT was able to simulate flows in river basins in the southern of Espírito Santo state, since there were not many gaps in the monitored data, and also being able to simulate data from other periods for which the parameters were not adjusted
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Fukunaga, Danilo Cesar. "Estimação de vazão em bacias hidrográficas do sul do Espírito Santo usando o SWAT." Universidade Federal do Espírito Santo, 2012. http://repositorio.ufes.br/handle/10/5819.
Анотація:
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Previous issue date: 2012-08-24O aumento da atividade econômica e do número de habitantes no mundo, juntamente com o uso não sustentável dos recursos hídricos, os despejos de efluentes sem tratamento no ambiente e o manejo inadequado das bacias hidrográficas, têm contribuído para diminuição da disponibilidade de água no planeta. Apesar de ser um recurso natural renovável, a água que retorna da atmosfera não ocorre de maneira uniformemente distribuída, nem no espaço geográfico, nem no tempo, tornando a sua boa gestão essencial para diminuição das consequências desastrosas dos eventos extremos de cheia e de escassez. Mas, uma gestão exitosa requer, além de profissionais qualificados, o uso de ferramentas para suporte à tomada de decisão. Neste contexto, a utilização de modelos hidrológicos pode auxiliar no planejamento e avaliação de práticas conservacionistas de solo e água e de manejo de bacias hidrográficas. Do exposto, o presente estudo teve o objetivo de avaliar a aplicabilidade do SWAT para a estimação de vazões em bacias hidrográficas no sul do Estado do Espírito Santo. Foram estudadas: a microbacia do córrego Jaqueira (MBJ), com aproximadamente 22,6 ha, e a sub-bacia do rio Itapemirim, à montante da estação fluviométrica de Rive (BIMR), com aproximadamente 2.237 km². Devido ao alto número de falhas e ao curto período de monitoramento hidrológico, não foi possível calibrar e verificar a aplicabilidade do modelo para a MBJ. Para a BIMR, na análise das vazões médias, estimou-se 45,5 m³ s-1 antes da calibração, e 32,6 m³ s-1 após a calibração, muito próxima da vazão média monitorada de 36,9 m³ s-1. Para o período de validação, a vazão média monitorada foi 22% maior (45,0 m³ s-1), enquanto a estimada foi de 33,9 m³ s-1, permanecendo próxima da vazão média estimada calibrada. Em análise gráfica, observou-se que, antes da calibração, as vazões mínimas estimadas ficaram abaixo das observadas, porém as vazões de pico eram superestimadas. Após a calibração, as vazões mínimas tiveram melhores correlações, enquanto as vazões de pico foram subestimadas. Na análise dos índices estatísticos, o R² passou de 0,74 para 0,76 após a calibração, mas foi reduzido para 0,63 no período de validação. Para o coeficiente de Nash Sufcliffe, houve uma melhora significativa do valor após a calibração, passando de -0,38 para 0,75, permanecendo com um valor aceitável de 0,57 no período de validação. O SWAT foi capaz de simular vazões em bacias hidrográficas do Sul do Espírito Santo, desde que não houvesse muitas falhas nos dados monitorados, sendo capaz inclusive de simular dados de outros períodos para os quais os parâmetros não foram ajustados
The increasing of world economic activity and the number of inhabitants, along with the unsustainable use of water resources, untreated wastewater release into the environment and inadequate watersheds management, has contributed to water availability decrease on the planet. Despite being a renewable natural resource, the water that returns from the atmosphere does not occur evenly distributed, either in geographic space or in time, making its good management essential to reduce disastrous consequences of extreme events of floods and droughts. But a successful management requires, as well as qualified professionals, the use of support decision tools. In this context, the use of hydrological models can assist in planning and assessment of conservation practices for soil and water and watershed management. In this light, the present study aimed to evaluate the SWAT capability to estimate flow in river basins in the southern of Espírito Santo state, Brazil. The Jaqueira stream watershed (MBJ), with approximately 22.6 ha, and Itapemirim river basin, upstream of the Rive fluviometric station (BIMR), with approximately 2,237 km², were studied. Due to the high number of gaps and short-term hydrological monitoring, was not possible to calibrate and verify model applicability for the MBJ. For BIMR, the analysis of the average flow rate was estimated by 45.5 m³ s-1, before calibration, and 32.6 m³ s-1 after calibration, closely to the monitored average flow, that was 36.9 m³ s-1. For the validation period, the average flow monitored was 22% higher (45.0 m³ s-1), while the estimated flow was 33.9 m³ s-1, remaining closely to the average calibrated estimated flow. In graphical analysis, it was observed that before calibration, the estimated minimum flow rates were below those observed, but the peak flows were overestimated. After calibration, the minimum flows had better correlations, while the peak flows were underestimated. In the analysis of statistical indexes, the R² increased from 0.74 to 0.76, after calibration, but was reduced to 0.63 in the validation period. For the Nash Sufcliffe coefficient, was verified a significant improvement of its value after calibration, from -0.38 to 0.75, remaining with an acceptable value in the validation period, 0.57. The SWAT was able to simulate flows in river basins in the southern of Espírito Santo state, since there were not many gaps in the monitored data, and also being able to simulate data from other periods for which the parameters were not adjusted
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Adnan, Aneela. "The After-School Extracurricular Needs of Swat’s College Girls." Thesis, University of Oregon, 2019. http://hdl.handle.net/1794/24543.
Анотація:
Gender disparity in education is a global challenge. School-age girls are often denied equal opportunities as enjoyed by boys. This research aims to improve the poor state of female education in Pakistan by exploring options to develop a community space for college age girls in Swat.
This thesis focuses on the former princely state of Swat in northern Pakistan, an example of a place whose history of prioritizing education is largely overlooked. The Swat state heavily promoted education, but following its merger with Pakistan in 1969, many of the institutions it had created faltered. The Taliban takeover of the area in 2007 – 2009 further exacerbated the decline of education in the valley. Drawing upon the experiences of Ophelia’s Place in Eugene, Oregon, and field interviews with over a hundred college girls and administrators, I have identified activities to enhance girls’ education in Swat by developing innovative after-school possibilities.
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Sakura-Lemessy, Donna-May G. "A Multi-Model Approach to Predicting Pathogen Indicator Bacteria Loading in TMDL Analyses." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/338.
Анотація:
This dissertation utilizes data from four sub-watersheds in the Little River Experimental Watershed, GA to develop models to improve forecast predictions related to the management of surface-water pollution due to non-point source runoff. Non-point source pollution is the primary cause of US surface-water quality impairment and a main transport mechanism for pathogens and other pollutants into receiving surface water bodies (US EPA 2008). In response to pollution reduction and watershed remediation mandates under the Federal Clean Water Act (1972)-particularly the Total Maximum Daily Load (TMDL) program-the role of water quality modeling in effectively rehabilitating impaired waters has taken on greater importance. Consequently, the significance of this study is that it is the first of its kind to incorporate a multi-model approach to address limitations in using single water quality models. In this regard, it builds on water quality engineering research by presenting methods to estimate contaminant concentrations and reduce uncertainty in overall model predictions in impaired water-bodies. Methodologically, the key point of departure in this dissertation is centered on the fact that water quality modeling is the cornerstone of TMDL analyses but the associated prediction uncertainty affects their adequacy in providing reliable contaminant loadings estimates in an impaired water body. As such, utilizing hydrological and water-quality process equations embedded in the two most widely used watershed-scale models, the Soil and Water Assessment Tool (SWAT) and Hydrological Simulation Program-Fortran (HSPF), and observed data from the sub-watersheds mentioned above, the dissertation addresses this limitation by combining results from the two competing models to reduce uncertainty and enhance accuracy of predictions. The study was conducted in two phases. First, HSPF and SWAT-two extensively-used, scientifically-rigorous, US EPA-approved watershed-scale codes-were used to build models of the four study catchments. The models were individually calibrated and shown (based on Nash-Sutcliffe Efficiency (NSE) ratios) to produce reliable simulations of the hydrologic and water quality conditions in the watershed. The second phase of the analysis involved using a multi-model approach to combine model forecasts. Model combination, introduced by Bates and Granger in 1969, has emerged as a viable analytical technique (Claesken and Hjort, 2008; Ajami et al., 2006) and widely-used across disciplines to improve model-forecasting results (Kim et al., 2006; Shamseldin et al., 1997; Granger, 2001; Clemens, 1989; Thompson, 1976; Newbold and Granger, 1974; Dickinson, 1973). After calibration, the model predictions were combined for each catchment using three different methods: the Weighted Average Method (WAM), the Nash-Sutcliffe Efficiency Maximization Method (NSE-max) and an Artificial Neural Network Method (ANN). Comparison of the results of the multi-model formulation with original individual model results showed improved estimates with all three combination methods. The improvement in model accuracy (based on NSE ratios) varied from modest to significant in both hydrologic and water quality variables. These improvements were attributed to a reduction in model structural uncertainty resulting from the ability to capture aspects of some of the more complex watershed interactions from exogenous information provided by the contributing models. It should be noted here, however, that as model availability increases, if additional models (beyond those utilized here) are used with this approach, care should be taken to ensure the credibility of each individual model for simulating the watershed scale processes under review. Limitations of this study include possible bias introduced by the use of deterministic models to estimate probabilistic contaminant distributions, limitations in available data, and the use of a seven-year study period that did not account for possible impacts of shorter periods of extreme hydrologic conditions on the individual model performances and model combination weightings. Recommendations for future research include (a) improving watershed-scale codes to better describe the probability distribution functions characteristic of contaminant distributions and data collection on wildlife species and populations; and investigating the fate and transport processes of pathogenic indicator bacteria deposited in forested areas and the impact of extreme hydrologic conditions on model performance and weighting. Overall, the findings from this dissertation suggest that water quality modeling incorporating a multi-model approach has the potential to significantly improve predictions compared to the predictions obtained when only one model is used. Clearly, the findings reported here have significant implications in improving TMDL analyses and remediation plans by presenting an approach that exploits the strengths of two of the most complete and well-accepted watershed-scale water quality models in the United States. Moreover, the findings of this dissertation auger well for the future of TMDL management in that it provides a more robust and cost effective basis for policy makers to decide on effective management strategies that incorporate acceptable risk, allowable loading and land use.
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Bouilhol, Pierre. "Structural, petrological and geochemical constraints on transfer and evolution of arc magmas in the mafic-ultramafic Sapat Complex (Kohistan; Northern Pakistan) /." Zürich : Eidgenössische Technische Hochschule, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18081.
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Reungsang, Pipat. "Application of SWAT model in predicting water quantity and quality for U.S. and Thailand watersheds." [Ames, Iowa : Iowa State University], 2007.