Published Article / This paper presents the set-up and the performance of the SWAT model in the Modder River Basin. Two techniques widely used, namely quantitative statistics and graphical techniques, in evaluating hydrological models were used to evaluate the performance of SWAT model. Three quantitative statistics used were, Nash-Sutcliffe efficiency (NSE), present bias (PBIAS), and ratio of the mean square error to the standard deviation of measured data (RSR). The performance of the model was compared with the recommended statistical performance ratings for monthly time step data. The model performed well when compared against monthly model performance ratings during calibration and validation stage.

<p>Soil and water assessment tool model (SWAT model) is a widely used model when dealing with large and complex watershed simulations. To correctly predict runoff of a watershed, auto-calibration methods are applied. Among all the platforms, SWAT CUP is widely used in the SWAT model community. The new web-based calibration platform: SWATShare is also gaining its popularity due to the benefits of user-friendly interface, access to high-performance computing resources, and collaborative interface. While the algorithm implemented in SWAT CUP is Sequential Uncertainty Fitting version 2 (SUFI2), Sorting Genetic Algorithm II (NSGA-II) is the algorithm employed by SWATShare. There is a limited amount of research comparing the model performance between these two calibration algorithms and platforms. </p> <p> </p> <p>This study aims to examine whether the performances of calibrated models are providing equally reliable results. Thirty US watersheds are studied in this research, SWAT models were calibrated using seven years of rainfall data and outflow observations from 2001 to 2007, and then the models were validated using three years of historical records from 2008 to 2010. Inconsistency exists between different algorithms calibrated parameter sets, and the percentage difference between parameter values ranges from 8.7% to 331.5%. However, in two-thirds of the study basins, there is no significant difference between objective function values in two algorithms calibrated models. Correlations are examined using values of parameters and watershed features. Among all the features and parameters, Length of reach and GW_DELAY, CH_N2 and ALPHA_BF, climate zone and GWQMN, SFTMP and NSE have medium correlation exist in both SWATShare and SWAT CUP calibrated models among 30 watersheds. The correlation coefficient difference between them are less than 0.1. When visualizing results by Ecoregions, KGE and NSE are similar in calibrated models from both tools. </p> <p> </p> <p>The initial parameter range used for SWAT CUP calibration could lead to satisfactory results with greater than 0.5 objective function values. However, the parameter values of the calibrated model might not be presenting a real physical condition since they are out of the realistic range. The inaccurate parameter values might lead to lower objective function values in the validation. The objective function values can be improved by setting the range of parameter values to match the realistic values. </p> <p> </p> <p> </p> <p>By comparing two tools, SWATShare accurately calibrates parameter values to a realistic range using default range in most cases. For those models with an unsatisfactory result from SWATShare, the objective function values could be improved after specifying the parameters to the best-fit range given by SWAT CUP results. Also, for those watersheds which have similar satisfactory calibrated objective values from both tools, constraining the parameter to a reasonable range could generate a new calibrated model that performs as well as the original one. Using the approach to constrain parameter values to a realistic range gradually can exclude some statistically satisfactory but physically meaningless models. Comparing two auto-calibration software, SWATShare accurately calibrates parameter values to a realistic range using default range in most cases. Also, in some of the ecoregions, the best parameter sets in SWATShare fall in a more physically meaningful range. Overall, the newly emerged platform, SWATShare, is found to have the capability of conducting good SWAT model calibration. </p>

No description available.

A expansão do cultivo de cana-de-açúcar motivada pelo aumento na demanda por etanol após lançamento da tecnologia fex fuel, resultou em grandes transformações na paisagem. O estado de São Paulo absorveu boa parte das áreas de expansão, que se instalaram em novas regiões do estado. A expansão ocorrida gera reflexões sobre os impactos ambientais negativos associados à cultura canavieira, sobretudo quanto às alterações no regime hidrossedimentológico das bacias hidrográficas. Neste contexto o presente estudo buscou avaliar a influência da expansão do cultivo da cana de açúcar sobre os aspectos hidrossedimentológicos (taxa de escorrimento superficial e produção de sedimento) em uma região onde houve um aumento significativo desta cultura. O local de estudo é a microbacia do córrego Cana do Reino, localizada no município de Votuporanga &#8211; SP. A avaliação se deu por meio de um comparativo entre as taxas de escorrimento e da produção de sedimentos para os cenários antes do período de expansão do cultivo desta cultura (2005) e após a expansão (2014), utilizando o Modelo SWAT. As simulações das vazões médias mensais apresentaram resultados satisfatórios após a calibração. Nesta etapa obtiveram-se valores para os coeficientes de eficiência de Nash-Sutcliffe (NSE), coeficiente de determinação (R²) e percentual de tendências (PBIAS) de respectivamente, 0,85, 0,82 e -1,5. Na validação observou-se valores de NSE, R² e PBIAS, iguais a 0,76, 0,81 e -9,0, respectivamente. Nas simulações contatou-se que as taxas médias de escorrimento superficial e produção de sedimentos para o cenário de 2005 foram de 44 mm e 2,6 ton.ha-1.ano-1. Para o cenário de 2014 obteve-se 70 mm e 4,5 ton.ha-1.ano-1. A partir dos resultados obtidos, conclui-se que o Modelo SWAT demonstrou-se satisfatório para a análise comparativa entre os cenários. / The expansion of sugar cane cultivation motivated by the increased demand for ethanol after the launching of the fex fuel technology has resulted in major changes in the landscape. São Paulo state has absorbed many of the expansion areas settled in new regions. Such an expansion has given rise to reflections on the negative environmental impacts associated with sugarcane crop, especially regarding changes in the hydrosedimentological regime of river basins. The present study evaluates the influence of the expansion of sugar cane cultivation on hydrosedimentological aspects (rate of runoff and sediment production) in a region of significant increase in this culture. The study site is Cana do Reino watershed, located in Votuporanga city &#8211; SP. The evaluation was conducted through a comparison between the runoff rates and sediment yield for the scenarios before (2005) and after their expansion (2014) and based on SWAT model. Simulations of monthly average flow rates showed satisfactory results after calibration. Values of 0.85, 0.82 and -1.5 were obtained for the Nash-Sutcliffe efficiency coefficient (NSE), coefficient of determination (R²) and percentage of trends (PBIAS), respectively. The validation showed values of NSE, R² and PBIAS of 0.76, 0.81 and -9.0, respectively. The simulations revealed the average rates of runoff and sediment yield for the 2005 scenario were 44 mm and 2.6 ton.ha-1.ano-1, whereas values of 70 mm and 4.5 ton.ha-1.ano-1 were obtained for the 2014 scenario. According to the results, SWAT model proved satisfactory for a comparative analysis between the scenarios.

A total maximum daily load (TMDL) assessment in the Upper North Bosque River (UNBR) has mandated reductions of soluble reactive phosphorus (SRP). The large concentrations of dairies in the UNBR watershed have been identified as a source of the SRP. Agricultural best management practices (BMPs) can be used to reduce in-stream loads of manure nutrients from confined dairy feeding operations (CAFOs). A new BMP utilizes turfgrass sod to export composted dairy manure nutrients out of the impaired watershed in a sustainable manner. Previous plot-scale experiments have showed that 46 to 77% of applied phosphorus (P) and 36 to 47% of applied nitrogen (N) were removed in a single sod harvest. Two, 1.4 ha turfgrass fields were instrumented to measure runoff flow and sediment and nutrient transport. One turfgrass field was topdressed with composted dairy manure and fertilizer N and the other with fertilizer N only. A total of 3.5% of the applied manure P and 3.1% of applied manure N were lost in the surface runoff over a 1.5 year period. The runoff data from the experimental fields were used to calibrate and validate Soil and Water Assessment Tool (SWAT) model simulations of flow, sediment, organic, and mineral nutrients. The Nash-Sutcliffe model fit statistic was greater than 0.6 for flow, sediment, and nutrients during the calibration period and greater than 0.3 during the validation period. Research results indicated that turfgrass sod can be used to export composted dairy manure out of impaired watersheds to improve water and soil quality.

A total maximum daily load (TMDL) assessment in the Upper North Bosque River (UNBR) has mandated reductions of soluble reactive phosphorus (SRP). The large concentrations of dairies in the UNBR watershed have been identified as a source of the SRP. Agricultural best management practices (BMPs) can be used to reduce in-stream loads of manure nutrients from confined dairy feeding operations (CAFOs). A new BMP utilizes turfgrass sod to export composted dairy manure nutrients out of the impaired watershed in a sustainable manner. Previous plot-scale experiments have showed that 46 to 77% of applied phosphorus (P) and 36 to 47% of applied nitrogen (N) were removed in a single sod harvest. Two, 1.4 ha turfgrass fields were instrumented to measure runoff flow and sediment and nutrient transport. One turfgrass field was topdressed with composted dairy manure and fertilizer N and the other with fertilizer N only. A total of 3.5% of the applied manure P and 3.1% of applied manure N were lost in the surface runoff over a 1.5 year period. The runoff data from the experimental fields were used to calibrate and validate Soil and Water Assessment Tool (SWAT) model simulations of flow, sediment, organic, and mineral nutrients. The Nash-Sutcliffe model fit statistic was greater than 0.6 for flow, sediment, and nutrients during the calibration period and greater than 0.3 during the validation period. Research results indicated that turfgrass sod can be used to export composted dairy manure out of impaired watersheds to improve water and soil quality.

Submitted by Nivaldo Carleto null (nivaldo.carleto@fatectq.edu.br) on 2016-06-20T16:52:44Z No. of bitstreams: 1 TESE-NIVALDO CARLETO-JUNHO-2016-VERSÃO FINAL.pdf: 5994341 bytes, checksum: 0eb3de1f968890a8c3dd0c412701126f (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-06-23T14:03:41Z (GMT) No. of bitstreams: 1 carleto_n_dr_jabo.pdf: 5994341 bytes, checksum: 0eb3de1f968890a8c3dd0c412701126f (MD5) / Made available in DSpace on 2016-06-23T14:03:41Z (GMT). No. of bitstreams: 1 carleto_n_dr_jabo.pdf: 5994341 bytes, checksum: 0eb3de1f968890a8c3dd0c412701126f (MD5) Previous issue date: 2016-06-09 / 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.

A expansão do cultivo de cana-de-açúcar motivada pelo aumento na demanda por etanol após lançamento da tecnologia fex fuel, resultou em grandes transformações na paisagem. O estado de São Paulo absorveu boa parte das áreas de expansão, que se instalaram em novas regiões do estado. A expansão ocorrida gera reflexões sobre os impactos ambientais negativos associados à cultura canavieira, sobretudo quanto às alterações no regime hidrossedimentológico das bacias hidrográficas. Neste contexto o presente estudo buscou avaliar a influência da expansão do cultivo da cana de açúcar sobre os aspectos hidrossedimentológicos (taxa de escorrimento superficial e produção de sedimento) em uma região onde houve um aumento significativo desta cultura. O local de estudo é a microbacia do córrego Cana do Reino, localizada no município de Votuporanga &#8211; SP. A avaliação se deu por meio de um comparativo entre as taxas de escorrimento e da produção de sedimentos para os cenários antes do período de expansão do cultivo desta cultura (2005) e após a expansão (2014), utilizando o Modelo SWAT. As simulações das vazões médias mensais apresentaram resultados satisfatórios após a calibração. Nesta etapa obtiveram-se valores para os coeficientes de eficiência de Nash-Sutcliffe (NSE), coeficiente de determinação (R²) e percentual de tendências (PBIAS) de respectivamente, 0,85, 0,82 e -1,5. Na validação observou-se valores de NSE, R² e PBIAS, iguais a 0,76, 0,81 e -9,0, respectivamente. Nas simulações contatou-se que as taxas médias de escorrimento superficial e produção de sedimentos para o cenário de 2005 foram de 44 mm e 2,6 ton.ha-1.ano-1. Para o cenário de 2014 obteve-se 70 mm e 4,5 ton.ha-1.ano-1. A partir dos resultados obtidos, conclui-se que o Modelo SWAT demonstrou-se satisfatório para a análise comparativa entre os cenários. / The expansion of sugar cane cultivation motivated by the increased demand for ethanol after the launching of the fex fuel technology has resulted in major changes in the landscape. São Paulo state has absorbed many of the expansion areas settled in new regions. Such an expansion has given rise to reflections on the negative environmental impacts associated with sugarcane crop, especially regarding changes in the hydrosedimentological regime of river basins. The present study evaluates the influence of the expansion of sugar cane cultivation on hydrosedimentological aspects (rate of runoff and sediment production) in a region of significant increase in this culture. The study site is Cana do Reino watershed, located in Votuporanga city &#8211; SP. The evaluation was conducted through a comparison between the runoff rates and sediment yield for the scenarios before (2005) and after their expansion (2014) and based on SWAT model. Simulations of monthly average flow rates showed satisfactory results after calibration. Values of 0.85, 0.82 and -1.5 were obtained for the Nash-Sutcliffe efficiency coefficient (NSE), coefficient of determination (R²) and percentage of trends (PBIAS), respectively. The validation showed values of NSE, R² and PBIAS of 0.76, 0.81 and -9.0, respectively. The simulations revealed the average rates of runoff and sediment yield for the 2005 scenario were 44 mm and 2.6 ton.ha-1.ano-1, whereas values of 70 mm and 4.5 ton.ha-1.ano-1 were obtained for the 2014 scenario. According to the results, SWAT model proved satisfactory for a comparative analysis between the scenarios.

Tanzania, like other developing countries in the tropics is severely affected by the degradation of water resources owing to improper land management practices. Such practices affect water supply through soil erosion which does not only cause sedimentation of rivers and water bodies but also leads to a reduction in the rainwater infiltration capacity of soils. This thesis seeks to demonstrate how the implementation of proper land management measures can reduce soil erosion and increase water supply in the Morogoro River catchment (Uluguru Mountains). The proper practices referred to are the soil and water conservation (SWC) approaches which include contour farming, fanya juu terracing and bench terracing. The thesis combines social science and geoscience methods in a synergetic manner to address this research problem. To understand how and to what degree SWC methods affect water fluxes and sediment yields, the hydrological model SWAT (Soil and Water Assessment Tool) was applied. Before carrying out the modelling procedures, it was necessary to examine the level of SWC adoption among farmers and factors influencing the process so as to establish the baseline. To this end, biophysical and socio-economic factors assumed to affect farmers’ adoption tendency were examined using a household questionnaire. Modelling results indicate that if correctly implemented contour farming, fanya juu terracing and bench terracing would significantly reduce sediment yield at different rates. The reduction would range approximately between 1% - 85% with the highest percentage change achieved by practicing the three SWC methods simultaneously. However, such SWC measures would not increase water flow annually owing to evapotranspiration losses. Nevertheless, according to modelling results groundwater storage would be increased by about 14% and hence contributing to water supply during the dry season. The household questionnaire survey suggests that the adoption of SWC methods in the study area is very low and complex. While age of the head of household, access to extension (professional) services, household annual income and proximity to the farm significantly influenced farmers’ decision to adopt SWC, gender of the head of household, slope characteristics of the farm, number of adults in the household and farmer’s perception on soil erosion effects had no considerable influence on adoption. Therefore, to successfully realize the SWC benefits demonstrated by the modelling results, smallholder farmers upstream of the catchment should be incentivized to implement proper land management practices. Payment for ecosystem services scheme appears to be a suitable strategy. To make this operational, the Tanzanian government should establish a national water fund which will finance watershed management activities. The methodological approach employed in this thesis is transferrable to other sites with problems comparable to the studied catchment.

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.