Dissertations / Theses: 'Hydrological simulator'

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Fensterseifer, Sandro Luciano Barreto. "INFLUÊNCIA DA RESOLUÇÃO ESPACIAL DO PIXEL NA APLICAÇÃO DO MODELO DE SIMULAÇÃO SWAT NA BACIA HIDROGRAFICA DO RIO GUAPORÉ, RS." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/3774.

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Today we know the need to preserve environmental resources, which include soils and hydrology. Estimates of water loss and soil erosion are held in different countries, using empirical or conceptual models such as SWAT (Soil and Water Assessment Tool), used to predict the impact of changes in the use and soil management, among others on soil loss and the flow of the watercourse. This model, through their routines, is able to simulate and quantify in a watershed as the dynamics of water flow and sediment occurs, the supply of information on the maps and tabular data format is required. This thesis set up two goals: first to identify the most appropriate spatial resolution for simulations, comparing the measured field data with simulated data flow and sediment yield. To this end, we analyzed how the product image affected the performance of the SWAT simulation application without being calibrated by changing their spatial resolutions of 10, 30, 50, 100 and 200 meters. After there were three analysis processes to determine which resolution gave better results of simulation, called analysis of percentage, and statistical regression, concluding that the image with 200 meter resolution showed the best results of simulation of liquid flow in the channel and without sediment transport model calibration. The second objective is to perform a simulation for basin Guapore validate and calibrate the model for liquid flow, analyzing the results for the sediment delivery with a period of 10 years of data. Performed the simulation is performed sensitivity analysis indicated that seven parameters as the most sensitive. Then ensued for calibration, effecting to change these parameters manually for flow and later to sediment production. Was used to analyze the efficiency calibration, the coefficient of efficiency. According to bibliography, this should keep values above 0.50 to be considered calibrated. For flow data were obtained for a range of average six years analyzed 0, 578 After calibration values, executed to validate the model using a seven-year period, reaching up to data an average flow of 0.68 COE. The model presented below one year with values determined by the bibliography, being satisfactory calibration and validation. As for the transport of sediment was not possible to calibrate and validate the model because the coefficient of efficiency showed high values, inferring that the main causes have been simplifying the soil loss equation uses the simulator to make some calculations, especially related to the length and steepness of slope, and basin size. Furthermore, by deducting the measured sediment data showed high variability within months of the years, making it difficult adjusting the parameters. It was concluded that the simulation process is valid for analysis and establishment of public conservation measures and preventive use of environmental resources, especially those related to the cultivation of land, and that the most appropriate spatial resolution of 200 meters for large basins. This resolution is not, perhaps, the reality for small basins, further studies should be performed. Sabe-se da necessidade de preservar os recursos ambientais, onde incluem-se os solos e a hidrologia. Estimativas da perda de água e solo por erosão são realizadas em diversos países, utilizando-se modelos empíricos ou conceituais, como o SWAT (Soil and Water Assessment Tool), utilizado para predizer o impacto das alterações no uso e no manejo do solo, entre outros, sobre a perda de solo e a vazão de curso de água. Este modelo, através de suas rotinas, tem condições de simular e quantificar em uma bacia hidrográfica como ocorre a dinâmica de fluxo de água e sedimentos, sendo necessário o abastecimento de informações no formato de mapas e dados tabulados. Nesta tese estabeleceram-se dois objetivos: o primeiro identificar qual a resolução espacial mais adequada para simulações, comparando-se dados medidos a campo com dados simulados de vazão e produção de sedimentos. Para tanto, analisou-se como o produto imagem afetou o desempenho de simulação do aplicativo SWAT sem estar calibrado, alterando-se as respectivas resoluções espaciais das imagens em 10, 30, 50, 100 e 200 metros. Após realizaram-se três processos de análise para determinar qual resolução gerou melhores resultados de simulação, denominadas de análise de percentagem, estatística e regressão, concluindo-se que a imagem com 200 metros de resolução apresentou os melhores resultados de simulação de vazão liquida no canal e transporte de sedimentos sem a calibração do modelo. O segundo objetivo é realizar uma simulação para a bacia de Guaporé validar e calibrar o modelo para vazão líquida, analisando-se os resultados para o aporte de sedimentos com um período de 10 anos de dados. Realizada a simulação, executou-se análise de sensibilidade que indicou sete parâmetros como os mais sensíveis. Seguiu-se, então, para calibração, efetivando-se a mudança destes parâmetros de forma manual para vazão e posteriormente para produção de sedimentos. Utilizou-se, para analisar a eficiência da calibração, o coeficiente de eficiência. Conforme a bibliografia, este deverá manter valores acima de 0,50 para ser considerado como calibrado. Para os dados de vazão obtiveram-se valores médios para um intervalo de seis anos, analisados de 0, 578. Após a calibração, executou-se a validação do modelo utilizando-se um período de sete anos, alcançando-se para os dados de vazão um valor médio de COE de 0,68. O modelo apresentou um ano com valores abaixo do determinado pela bibliografia, sendo satisfatória a calibração e validação. Já para o transporte de sedimentos não foi possível calibrar o modelo e validar, pois o coeficiente de eficiência apresentou valores elevados, inferindo-se que as principais causas foram a simplificação da equação de perdas de solo que o simulador utiliza para fazer alguns cálculos, principalmente relacionados ao comprimento de rampa e declividade, e o tamanho da bacia. Além disso, deduzindo-se que os dados de sedimentos medidos apresentaram uma alta variabilidade dentro dos meses nos anos, o que dificultou o ajuste dos parâmetros. Concluiu-se que o processo de simulação é valido para análises e estabelecimento de medidas públicas de conservação e uso preventivo dos recursos ambientais, principalmente aqueles relacionados ao cultivo de solos, e que a resolução espacial mais adequada é de 200 metros para grandes bacias. Esta resolução não é, talvez, a realidade para pequenas bacias, devendo ser realizado estudos complementares.

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VilariÃ±o, Daniel R. "Hydrologic calibration of the Cub Run Watershed using the PC version of the Hydrological Simulation Program - FORTRAN (HSPF)." Thesis, Virginia Tech, 1996. http://hdl.handle.net/10919/44438.

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The Hydrological Simulation Program - FORTRAN (HSPF) in its personal computer version, release 10.10, was used to perform the hydrological simulation of a sub-watershed of the Occoquan River drainage basin. The sub-watershed selected was the Cub Run Watershed located in the northern area of the Occoquan River catchment. A model in the form of a User Control Input (UCI) file was prepared. The Cub Run Watershed was analyzed considering its geological, edaphic and weather characteristics, and segmented accordingly. The model was calibrated to adjust simulated results to observed data. Several calibration runs were executed and a final run was done considering a further segmented watershed. The simulation results were good even when not all the desired data could be found. The annual percent difference between the best calibration run and the observed results was 21.28%. The ten-month percent difference, excluding June and July, was 5.82 %. The first value is a fair result for hydrologic calibration, the second value is an excellent result for the same type of calibration. Additional segmentation did not further improve the results obtained during the best calibration run. Differences in the calibration when considering just a pervious segment or two segments (one pervious and one impervious) could be noted, indicating the importance of considering impervious surfaces for the simulation. HSPF reacted quite logically to variations in the calibration parameters and the results from those variations could be predicted beforehand. In summary, the PC version of HSPF was demonstrated to be a good management tool for the hydrological simulation of this watershed. Master of Science

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Vilariño, Daniel R. "Hydrologic calibration of the Cub Run Watershed using the PC version of the Hydrological Simulation Program - FORTRAN (HSPF) /." This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-08252008-162353/.

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Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1996. Vita. Abstract. Maps in back pocket. Includes bibliographical references (leaves 171-177). Also available via the Internet.

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Cameron, David. "Estimating flood frequency by continuous simulation." Thesis, Lancaster University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321899.

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This thesis explores several important hydrological modelling topics surrounding the use of continuous rainfall-runoff simulation for flood frequency estimation. A continuous simulation methodology suitable for flood frequency estimation is developed. The methodology features a rainfall-runoff model (TOPMODEL, e.g. Beven, 1997), a new profile-based stochastic rainfall model (developed in this thesis), and an uncertainty estimation procedure (Generalised Likelihood Uncertainty Estimation, or GLUE e.g. Beven and Binley, 1992). By explicitly accounting for a catchment's soil moisture conditions, allowing the direct simulation of long return period flood events (via the coupling of TOPMODEL with the stochastic rainfall model), and quantifying the uncertainty associated with the simulated flood estimates, this methodology is an attractive alternative to the more traditional statistical and event-based techniques available for flood frequency estimation. It is tested successfully using data obtained from five, gauged, UK catchments. In addition to exploring the possible consistency between flood peak and continuous flow rainfall-runoff model parameterisations, the methodology is used to examine the potential impacts of climatic change upon flood frequency. Two further issues are also addressed. These are: the choice of stochastic rainfall model (for use within continuous simulation studies), and the modification of a pulse-based stochastic rainfall model for enhanced extreme rainfall simulation.

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Ishak, Asnor Muizan. "Hydrological simulation aided by numerical weather prediction model." Thesis, University of Bristol, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559471.

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In many water resources and hydrological projects, it is not always possible to get access to in-situ long-term time series weather measurements, especially for ungauged catchments. Even with gauged catchments, it is common that only rain gauge and river level data are available; other weather variables such as solar radiation, wind speed, surface temperature, surface air pressure and relative humidity are usually missing and if available are generally not in continuous form. These weather variables are basic building blocks of the global hydrological cycle that includes evapotranspiration (ET 0) and runoff estimation. The ET 0 and runoff can be estimated from the Penman-Monteith equation and rainfall runoff modeling respectively. This thesis explored a potential application of downscaled global reanalysis weather data using Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model 5 (MMS). MMS is able to downscale the global weather data down to a much finer resolution in space and time for use in local hydrological investigations. The exploration of downscaling the ERA-40 reanalysis data to the Brue catchment in Southwest England and the assessment of the relevant weather variables in comparison with those measured at the ground was described in the thesis. However, there is a problem in using these selected weather variables in hydrological processes due to uncertainties obtained from the mesoscale modelling. Therefore, this thesis focused on the improvement of the weather variables from the dynamical downscaling and statistical modeling. The improvement of dynamic downscaling with the MMS cumulus parameterization schemes (CPSs) by changing the horizontal and vertical resolutions are presented in this thesis for rainfall estimation. Meanwhile, the error correction with statistical models is an attempt to hybridize MMS with two regression models ( the multiple linear regression (MLR) and the nonlinear regression (NLR)) and two artificial intelligence systems (the artificial neural networks (ANNs) and the support vector machines (SVMs)). This exploration is to tackle the errors between the MMS downscaled and observed data in addition to other MMS derived hydro- meteorological parameters. The hold-out validation with a forward selection method was employed as an input variable selection procedure to examine the model generalization errors in these statistical models. Upon the implementation of the error correction technique of weather variables, a comparative study of runoff simulation via the PDM model was completed between the MMS downscaled, corrected and observed data. This thesis also presents a sensitivity analysis of six weather variables to ET 0 estimation and runoff simulation through various combinations of the Penrnan-Monteith equation and Probability Distributed Model (PDM}inputs. Finally, by this assessment of several case studies in this thesis, it has shown that the enhanced MMS modeling scheme with the correction approaches substantially improves the forecasted weather variables over the study area which is important for the hydrological processes.

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Stewart, Adam Gillis. "Hydrological modeling to support simulation of an ozone exceedance episode over Texas." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/19075.

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Zhang, Hongbin. "Urban flood simulation by coupling a hydrodynamic model with a hydrological model." Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/2797.

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This work introduces a new integrated flood modelling tool in urban areas by coupling a hydrodynamic model with a hydrological model in order to overcome the drawbacks of each individual modelling approach, i.e. high computational costs usually associated with hydrodynamic models and less detailed physical representations of the underlying flow processes corresponding to hydrological models. Crucial to the simulation process is to first divide the catchment hydraulic and hydrological zones where the corresponding model is then applied. In the hydrological zones that have more homogeneous land cover and relatively simple topography, a conceptual lumped model is applied to obtain the surface runoff, which is then routed by a group of pre-acquired ‘unit hydrographs’ to the zone border, for high-resolution flood routing in the hydraulic zones with complex topographic features, including roads, buildings, etc. In hydraulic zones, a full 2D hydrodynamic model is applied to provide more detailed flooding information e.g. water depth, flow velocity and arrival time. The new integrated flood modelling tool is validated in Morpeth, the North East of England by reproducing the September 2008 flood event during which the town was severely inundated following an intense rainfall event. Moreover, the coupled model is investigated and evaluated according to the effects from temporal and spatial resolutions, friction, rainfall, infiltration, buildings and coupling methods. In addition, the model is also employed to implement flood damage estimations with different scenarios of the upstream storage and flood defences in the town centre. Whilst producing similar accuracy, the new model is shown to be much more efficient compared with the hydrodynamic model depending on the hydrological zone percentage. These encouraging results indicate that the new modelling tool could be robust and efficient for practitioners to perform flood modelling, damage estimation, risk assessment and flood management in urban areas and large-scale catchments.

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Parsons, J. S. "A simulation model for subsurface and overland flow down a hillside in the Crimple Beck, N. Yorkshire." Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376984.

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Pina, Fulano Jasson. "The value of hydrological information in multireservoir systems operation." Doctoral thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/28228.

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La gestion optimale d’un système hydroélectrique composé de plusieurs réservoirs est un problème multi-étapes complexe de prise de décision impliquant, entre autres, (i) un compromis entre les conséquences immédiates et futures d’une décision, (ii) des risques et des incertitudes importantes, et (iii) de multiple objectifs et contraintes opérationnelles. Elle est souvent formulée comme un problème d’optimisation, mais il n’existe pas, à ce jour, de technique de référence même si la programmation dynamique (DP) a été souvent utilisée. La formulation stochastique de DP (SDP) permet la prise en compte explicite de l’incertitude entourant les apports hydrologiques futurs. Différentes approches ont été développées pour incorporer des informations hydrologiques et climatiques autres que les apports. Ces études ont révélé un potentiel d’amélioration des politiques de gestion proposées par les formulations SDP. Cependant, ces formulations sont applicables aux systèmes de petites tailles en raison de la célèbre « malédiction de la dimensionnalité ». La programmation dynamique stochastique duale (SDDP) est une extension de SDP développée dans les années 90. Elle est l’une des rares solutions algorithmiques utilisées pour déterminer les politiques de gestion des systèmes hydroélectriques de grande taille. Dans SDDP, l’incertitude hydrologique est capturée à l’aide d’un modèle autorégressif avec corrélation spatiale des résidus. Ce modèle analytique permet d’obtenir certains des paramètres nécessaires à l’implémentation de la technique d’optimisation. En pratique, les apports hydrologiques peuvent être influencés par d’autres variables observables, telles que l’équivalent de neige en eau et / ou la température de la surface des océans. La prise en compte de ces variables, appelées variables exogènes, permet de mieux décrire les processus hydrologiques et donc d’améliorer les politiques de gestion des réservoirs. L’objectif principal de ce doctorat est d’évaluer la valeur économique des politiques de gestion proposées par SDDP et ce pour diverses informations hydro-climatiques. En partant d’un modèle SDDP dans lequel la modélisation hydrologique est limitée aux processus Makoviens, la première activité de recherche a consisté à augmenter l’ordre du modèle autorégressif et à adapter la formulation SDDP. La seconde activité fut dédiée à l’incorporation de différentes variables hydrologiques exogènes dans l’algorithme SDDP. Le système hydroélectrique de Rio Tinto (RT) situé dans le bassin du fleuve Saguenay-Lac-Saint-Jean fut utilisé comme cas d’étude. Étant donné que ce système n’est pas capable de produire la totalité de l’énergie demandée par les fonderies pour assurer pleinement la production d’aluminium, le modèle SDDP a été modifié de manière à considérer les décisions de gestion des contrats avec Hydro Québec. Le résultat final est un système d’aide à la décision pour la gestion d’un large portefeuille d’actifs physiques et financiers en utilisant diverses informations hydro-climatiques. Les résultats globaux révèlent les gains de production d’énergie auxquels les opérateurs peuvent s’attendre lorsque d’autres variables hydrologiques sont incluses dans le vecteur des variables d’état de SDDP. The optimal operation of a multireservoir hydroelectric system is a complex, multistage, stochastic decision-making problem involving, among others, (i) a trade-off between immediate and future consequences of a decision, (ii) considerable risks and uncertainties, and (iii) multiple objectives and operational constraints. The reservoir operation problem is often formulated as an optimization problem but not a single optimization approach/algorithm exists. Dynamic programming (DP) has been the most popular optimization technique applied to solve the optimization problem. The stochastic formulation of DP (SDP) can be performed by explicitly considering streamflow uncertainty in the DP recursive equation. Different approaches to incorporate more hydrologic and climatic information have been developed and have revealed the potential to enhance SDP- derived policies. However, all these techniques are limited to small-scale systems due to the so-called curse of dimensionality. Stochastic Dual Dynamic Programming (SDDP), an extension of the traditional SDP developed in the 90ies, is one of the few algorithmic solutions used to determine the operating policies of large-scale hydropower systems. In SDDP the hydrologic uncertainty is captured through a multi-site periodic autoregressive model. This analytical linear model is required to derive some of the parameters needed to implement the optimization technique. In practice, reservoir inflows can be affected by other observable variables, such snow water equivalent and/or sea surface temperature. These variables, called exogenous variables, can better describe the hydrologic processes, and therefore enhance reservoir operating policies. The main objective of this PhD is to assess the economic value of SDDP-derived operating policies in large-scale water systems using various hydro-climatic information. The first task focuses on the incorporation of the multi-lag autocorrelation of the hydrologic variables in the SDDP algorithm. Afterwards, the second task is devoted to the incorporation of different exogenous hydrologic variables. The hydroelectric system of Rio Tinto (RT) located in the Saguenay-Lac-Saint-Jean River Basin is used as case study. Since, RT’s hydropower system is not able to produce the entire amount of energy demanded at the smelters to fully assure the aluminum production, a portfolio of energy contacts with Hydro-Québec is available. Eventually, we end up with a decision support system for the management of a large portfolio of physical and financial assets using various hydro-climatic information. The overall results reveal the extent of the gains in energy production that the operators can expect as more hydrologic variables are included in the state-space vector.

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Mattern, David Ellis 1957. "Hydrologic simulation of pinyon-juniper woodlands in Arizona." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277116.

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A physically-based, user friendly, hydrologic computer simulation model was developed for pinyon-juniper woodland watersheds. The data requirements are minimum, requiring vegetation conditions, basic soil survey information, and daily values for precipitation and temperature. The model predicts runoff from cleared and uncleared watersheds by simulating hydrologic processes on a daily basis. The model was tested with data from small pinyon-juniper watersheds in central Arizona. A crack-forming vertisol was the dominant soil type, and a special feature for addressing its effects on runoff was included. No significant difference between predicted and observed annual runoff was found at the ninety-five percent confidence level.

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Zhang, Fangli. "A particle-set distributed hydrological model for the dynamic simulation of surface runoff." HKBU Institutional Repository, 2017. https://repository.hkbu.edu.hk/etd_oa/472.

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1.1\xThis study proposed a particle-set distributed hydrological model for the dynamic simulation of rainfall-runoff process. With the supports of remote sensing, GIS, terrain analysis and distributed computing techniques, a representation-simplified and physically-based high-performance watershed framework has been developed. It simplifies the underlying watershed with a flow path network model, and represents the moving surface flow with independent runoff particles.;1.2\xThe original idea was to investigate a real-time modeling system for the space-time dynamics of increasingly frequent extreme rainfall events. Short-term heavy rains may cause further damages by spawning floods and landslides. It is quite essential to understand how the rainfall water moves across the watershed surface as early as possible. A modelling system with high-performance in simulation efficiency and space-time prediction accuracy would be very desirable.;1.3\xWatershed modeling is the primary way to explore the hydrological cycle at a local scale. Existing models are classified as empirical lumped, conceptual semi-distributed and physically-based distributed models. The first two types of models have focused more on predicting outlet discharges rather than estimating spatiotemporal flow dynamics. The application of physically-based models has always been hampered by some common shortcomings like over-parameterization, inflexibility and computational burden. With the increasing support from terrain analysis and parallel computing techniques, a number of previous studies have made some efforts to improve the performance in dynamic and real-time simulation. However, research gaps still exist in realistic representation, physical description and real-time simulation.;1.4\xThis study, therefore, developed the particle-set modeling system on the basis of flow path network model. This one-dimensional topological structure was created beforehand to represent the three-dimensional watershed, and a series of particle beams were dynamically generated to simulate the surface flow. Under the control of flow velocities, these runoff particles would keep on moving along with the flow paths, which can represent the spatial distributions of surface water in time.;1.5\xTo validate the proposed particle-set framework, a prototype of particle-set system was implemented by programming methods with the assistance of third-party platforms. Three experiments were undertaken to respectively evaluate the performance in prediction accuracy, simulation efficiency and parameter sensitivity. More specifically, a total of 10 rainfall events and up to 128 computer processors were tested. In addition, the influences of underlying spatial scale and source sampling density on hydrological responses were explored with comparative tests.;1.6\xThe accuracy validation comes in two parts, the representation loss in terrain analysis, and the discharge error in hydrological modeling. The experimental results indicate that the TIN-based flow path network has maintained the terrain features at a very high level with much less data storage, and the particle-set framework has achieved quite acceptable predictions of outlet discharges. Besides, the efficiency evaluation concerns with two aspects, parallel portion and parallel efficiency. The speed-up results indicate that about 99% of the computational workloads can be computed in parallel, and the particle-based scheme can achieve almost the ideal parallel efficiency. In addition, the sensitivity test focuses also on two parameters, underlying spatial scale and source sampling density. The preliminary results show that the particle-set model has shown a good reliability and stability as scale gets coarser or density becomes sparser.;1.7\xThis study will contribute to the understanding of short-term rainfall-runoff events at a basin scale. The particle-set distributed hydrological model has been proven to provide real-time spatio-temporal dynamics of surface flow. Further studies would still be required to apply it to real world scenarios.;1.8\xKeywords: terrain analysis, watershed hydrology, rainfall-runoff process, flow path network, particle system, parallel computing

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Samaniego-Eguiguren, Luis Eduardo. "Hydrological consequences of land use - land cover and climatic changes in mesoscale catchments." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10720630.

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Wang, Chen. "Simulation and Evaluation of Stream flow and Pesticide Prediction in Orestimba Creek Watershed using AnnAGNPS Model." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1564.

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Pesticides have been recognized as one major agricultural non-point source (NPS) pollution to the environment and surface water in United States. Numerous mathematical models have been developed over the last decades to simulate the fate and transport of NPS at watershed scale. Geographic Information System (GIS) combined with models extends the spatial and temporal scopes of the research by integrating a variety of climates, soils, land covers, and management practices. The Annualized Agricultural Nonpoint Source model (AnnAGNPS) has received considerable attention in the United States for estimating runoff, sediment yield, pesticide and nutrients transport from ungauged agricultural watershed. However, few studies have been conducted on pesticide loading prediction in surface water using AnnAGNPS. In this study, the AnnAGNPS model was calibrated and validated for prediction of stream flow and chlorpyrifos loading for an agricultural dominated watershed of Orestimba Creek, in Central Valley, California. Large amounts of chlorpyrifos are applied to almonds, walnuts and other stone-fruit orchards in this area every year, which caused significant concern regarding their contamination to the San Joaquin River. Variety of data obtained from multiple sources were utilized as model input, including climate, land use, topology, soil, crop management and schedule, non-crop data, and pesticide. The model's performance was quantitatively analyzed using mean, standard deviation, coefficient of determination (r2), coefficient of efficiency (NSE), and root mean square error (RMSE). Model's prediction was considered to be unsatisfactory if NSE < 0.36, satisfactory if 0.36 < NSE < 0.75 and good if NSE > 0.75. Monthly stream flow discharge prediction was satisfactory and fit the observed data during model calibration mode. The prediction had major improvement in validation mode with modified curve number and rainfall interception values (r2 = 0.78 and NSE = 0.77). The AnnAGNPS predictions of chlorpyrifos concentrations in runoff water were unsatisfactory in both calibration and validation modes. Predicted chlorpyrifos concentrations at rainfall events were 1/1000 of observed data and it was impossible to improve the results through any type of calibration. The overall results suggested the model's poor performance was most likely a result of coarse sampling resolution of observed chlorpyrifos concentrations and lack of irrigation data.

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Götzinger, Jens. "Distributed conceptual hydrological modelling - simulation of climate, land use change impact and uncertainty analysis." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-33499.

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Hartmann, Gabriele Maria. "Investigation of evapotranspiration concepts in hydrological modelling for climate change impact assessment." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-30863.

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Sorribas, Mino Viana. "Simulação da dinâmica de carbono em bacias hidrográficas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/49161.

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Na maior parte dos ecossistemas aquáticos a respiração excede a produção primária bruta autóctone, acarretando uma produção líquida de ecossistema negativa. Estudos recentes atribuem essa condição a processos de degradação de matéria orgânica alóctone, portanto o ciclo do carbono em corpos de água interiores deve estar pareado com o aporte de carbono orgânico originado na bacia hidrográfica. Este trabalho contribui para a melhor compreensão dos processos atuantes no ciclo de carbono em bacias hidrográficas, por meio de monitoramento de dados de campo, desenvolvimento e aplicação de modelagem matemática e simulação numérica. O estudo foi realizado utilizando dados de monitoramento na bacia hidrográfica do Rio Ijuí localizada no planalto meridional gaúcho. A exportação fluvial de carbono orgânico e inorgânico foi estimada a partir de dados de vazão e concentração. Um modelo baseado em processos para simulação da dinâmica de carbono, MGB-IPH-C, foi desenvolvido e acoplado ao modelo hidrológico MGB-IPH. O modelo hidrológico foi ajustado em diversos pontos de controle na bacia hidrográfica do Ijuí obtendo-se bons resultados, principalmente para as bacias de maior porte (>1000 km2). O modelo de carbono foi avaliado qualitativamente considerando a representação de processos conceituais e, quantitativamente, pela comparação das concentrações e fluxos simulados em relação aos obtidos pelos dados do monitoramento. Não foi possível identificar associações diretas entre as concentrações de carbono inorgânico ou orgânico e vazão, com base nos dados medidos em campo. As cargas médias de carbono nas bacias estudadas apresentaram valores abaixo da média global, na ordem de 25-40 kg.ha-1.ano-1 e 8-10 kg.ha-1.ano-1, para as frações inorgânica e orgânica, respectivamente. O MGB-IPH-C representou processos conceituais esperados, em especial, a acumulação no solo e o efeito da lavagem das águas sobre a concentração dos rios. Foi possível obter bons ajustes em escala anual para as cargas e concentrações médias de carbono na bacia de estudo. A simulação da dinâmica de carbono em ecossistemas aquáticos em pareamento com a bacia hidrográfica utilizando modelos conceituais determinísticos contribui para o entendimento dos processos operantes nesses sistemas e deve ser complementada por meio de análise de dados de monitoramento, em freqüência adequada à escala, com métodos empíricos. In most aquatic ecosystems respiration exceeds autochtonous gross primary production leading to a negative net ecosystem production. Recent studies attributes this condition to allochtonous organic matter degradation processes, so the inland water carbon cycle should be linked to the input of organic carbon from the catchment. This work contributes to a better comprehension of processes operating in the carbon cycle in river basins, throughout development and application of mathematical modeling and numerical simulation. The study was conducted using data of the Ijuí river watershed, located in the Planalto Meridional Gaúcho. Fluvial exports of organic and inorganic carbon were estimated from data measured in field. A process-based model for carbon dynamics simulation, MGB-IPH-C, was developed and coupled to the hydrological model MGB-IPH. The hydrological model was calibrated to various control points in the Ijui river basin with good results, especially in larger subwatersheds (>1000 km2). The carbon model was evaluated considering the representation of carbon dynamics conceptual processes and by comparison of observed carbon concentrations and export rates obtained by simulation and monitoring data. The estimates of annual export of carbon in the study area were below the global average, in magnitude of 25-40 kg/ha.yr and 8-10 kg/ha.yr for inorganic and organic carbon, respectively. The proposed carbon model, MGB-IPH-C, was able to simulate expected conceptual processes, in particular, the build-up on soil and the effect of wash-off on carbon concentration in river reaches. It was possible to obtain good fits for annual average carbon fluvial export rates and concentrations. The simulation of carbon dynamics in inland waters coupled with the watershed using conceptual deterministic models contributes to the understanding of processes operating on these systems and may be complemented throughout analysis of field data, at frequency appropriated to the scale, with empirical methods.

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Tahmasebi, Nasab Mohsen. "A New Macro-Scale Hydrologic Processes Simulator for Depression-Dominated Cold Climate Regions." Diss., North Dakota State University, 2019. https://hdl.handle.net/10365/29864.

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The primary objectives of this dissertation research are to (1) improve the understanding of macro-scale hydrologic processes in cold climate regions, (2) improve macro-scale representation and modeling of depression-dominated areas, and (3) improve land use variations in macro-scale hydrologic models. To achieve the objectives, (1) a Macro-Scale Hydrologic Processes Simulator (Macro-HyProS) is developed and tested in the Red River of the North Basin (RRB), (2) the impacts of sub-daily temperature fluctuations around the freezing temperature on snowmelt simulations are evaluated by using a hybrid temperature index method (HTIM), and (3) the effects of two high-resolution gridded temperature datasets on magnitude and distribution of snowmelt are assessed in the Missouri River Basin (MRB). Macro-HyProS is a grid-based daily hydrologic model that uses a unique LEGO-fashion horizontal layout to account for the within-grid heterogeneity of land use. The model incorporates five vertical bands, each of which simulates different hydrologic processes. Eventually, a grid-to-grid routing method is used to estimate outlet discharge. The simulation results from the first study accentuated the significance of frozen ground condition on the generation of surface runoff in the RRB. It was found that the concurrent occurrence of frozen ground condition, snowmelt events, and early spring rainfalls in the RRB made the basin prone to frequent spring floods. In addition, it was demonstrated that the abundant surface depressions across the RRB regulate the release of surface runoff and streamflow discharge. Results from the second study revealed that the HTIM improved the representation of temperature variations in snow models. It was found that the daily snowmelt simulations were significantly affected by the sub-daily temperature fluctuations, while the monthly and annual snowmelt results were less prone to such changes. Lastly, results from the third study indicated that although different temperature datasets captured the spatial and temporal patterns of snowmelt in the MRB, the quantities of the simulated snowmelt were different on the western side of the basin with complex topographical features. National Science Foundation (NSF) Experimental Program to Stimulate Competitive Research (EPSCoR) Center for Regional Climate Studies (CRSC)

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Geimer, Greg. "Modeling of conservation practices on a HUC-12 watershed scale using Hydrological Simulation Program -- FORTRAN." Thesis, University of Iowa, 2018. https://ir.uiowa.edu/etd/6422.

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Conservation practices are frequently used to try and restore the natural resilience of the landscape to retain water, decrease nutrient loads, and mitigate flooding. Quantifying the potential benefits of conservation practices can inform stakeholders and improve the effectiveness of watershed planning. To this end, an existing Hydrological Simulation Program --- FORTRAN (HSPF) model of the English River was enhanced to enable detailed modeling of conservation practices. Using site-specific nutrient removal wetlands and water and sediment control basins (WASCOBs) derived from the Agricultural Conservation Planning Framework (ACPF) two 12-digit hydrologic unit code (HUC-12) watersheds within the English River, Headwaters North English River and Gritter Creek, were selected for modeling. Wetlands drain much larger areas than ponds that currently exist in the two watersheds. Average flood peak reductions are over 50% near the wetland sites, and diminish moving downstream to a few percent or less at the watershed outlets. Many WASCOBs exist in the two watersheds, but WASCOB use is minimal in other areas of the state. WASCOBs provide slightly more flood storage than ACPF wetlands but the storage isy distributed throughout the watershed. As a result the simulations show that the peak reduction is greater than for wetlands at many locations.

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Dancel, Christopher Marlon. "An analysis of the hydrological cycle and poleward heat transports simulated by two climate models." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9783.

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Heat and Freshwater transport by the oceans and atmosphere are an integral part of the climate system, aiming to cool the Tropics and warm the Extra-Tropics. General Circulation Models (GCMs) are used to simulate the climate system, however a key weakness to them is the uncertainty associated with model predictions. One component of this uncertainty is due to the model structural bias associated with the choice of ocean model vertical coordinate type, which can have substantial feedback within a coupled ocean-atmosphere model. This thesis aims to investigate the Heat and Freshwater transport in the climate system with specific relevance to three main topics: 1. sensitivity of heat and freshwater transport to model numerics 2. coupling between heat and freshwater transport 3. changes to heat and freshwater transport to increasing CO2 concentration Firstly, the choice of ocean vertical coordinate on the computed heat and freshwater transport in the oceans and atmosphere was investigated. By comparing the models CHIME (isopycnal level ocean model) and HadCM3 (z-level ocean model) in a control climate, it was found that variations to the atmospheric latent and dry static energy transports were much larger than those induced from anthropogenic emission scenarios predicted by the latest IPCC report (AR4, 2007). Secondly, a new theory that constrained the ratio of ocean to atmospheric heat transport Ho/Ha as a function of ocean temperature and salinity was examined. This theory was tested using a control scenario from the HadCM3 model for mid-latitudes, finding good agreement over the Northern Hemisphere, though poorer performance over the Southern Hemisphere. Finally, climate snapshots in CHIME were analysed under an increasing CO2 environment. An examination of heat and freshwater transport for the ocean - atmosphere and the atmospheric dry static - latent energy components, showed significant compensation within each pair. Further investigation into the ocean overturning circulation and atmospheric moisture transport revealed: a salinification (freshening) of the Atlantic (Pacific), increased zonal moisture transport through Central America, and a weakening of the Atlantic meridional overturning circulation, validating CHIME's anthropogenic responses with predictions from AR4.

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Bourgin, François. "Comment quantifier l’incertitude prédictive en modélisation hydrologique ? : Travail exploratoire sur un grand échantillon de bassins versants." Thesis, Paris, AgroParisTech, 2014. http://www.theses.fr/2014AGPT0016/document.

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La modélisation hydrologique permet de quantifier la transformation pluie-débit au sein d’un bassin versant. Bien que les modèles parviennent généralement à représenter de manière acceptable le fonctionnement des bassins versants, cette représentation, nécessairement simplifiée, reste imparfaite, et une quantification des incertitudes est souhaitable. Cette thèse s’intéresse à la quantification de l’incertitude prédictive en modélisation hydrologique. Le principal objectif de nos travaux est d’explorer différentes méthodes qui permettent d’associer à des simulations ou des prévisions de débits déterministes des distributions probabilistes. Nous distinguons le contexte de simulation du contexte de prévision et adoptons dans ces deux cas une démarche comparative et pragmatique qui permet d’évaluer différentes approches sur un large échantillon de bassins versants français, à l’aide de critères d’évaluation adaptés. En simulation, nos travaux ont porté sur deux méthodes liées à l'estimation des paramètres des modèles hydrologiques, la méthode GLUE et le calage bayésien, ainsi que sur deux approches plus pragmatiques, l'approche multi-modèles, et le post-traitement statistique. Nos résultats suggèrent que les approches telles que GLUE qui ne s'appuient que sur un ensemble de différents jeux de paramètres ne parviennent pas, en général, à représenter de manière adéquate l'incertitude prédictive totale. L'utilisation d'un modèle d'erreur extérieur au fonctionnement interne du modèle hydrologique est nécessaire. Les méthodes de post-traitement suffisamment flexibles pour caractériser les erreurs résiduelles obtenues en calage parviennent à refléter de manière plus satisfaisante les marges d'erreurs du modèle hydrologique utilisé. Nous proposons également une méthode qui permet d'obtenir une estimation de l'incertitude prédictive pour les bassins non jaugés, au moyen d'un transfert des marges d'erreurs constatées sur les bassins jaugés. Les résultats indiquent que la méthode est prometteuse et fournit dans la plupart des cas des intervalles de confiance fiables et fins sur les sites non-jaugés. En prévision, nos travaux ont porté d'une part sur la comparaison de différentes méthodes de post-traitement statistique, et d'autre part sur l'interaction entre l'assimilation de données et le post-traitement au sein d'une chaîne de prévision hydrologique d'ensemble. Les résultats obtenus montrent l'importance de la prise en compte de l'évolution de l'incertitude prédictive en fonction de l'échéance de prévision et mettent en évidence les gains de performance qui peuvent être obtenus quand la quantification de l'incertitude s'appuie sur une meilleure caractérisation de la situation de la situation de prévision. Enfin, nos travaux indiquent que l'utilisation conjointe de l'assimilation de données et d'une méthode de post-traitement permet d'améliorer les performances d'une chaîne de prévision hydrologique d'ensemble Hydrological modelling aims to quantify the rainfall-runoff relationship at the catchment scale. Although hydrological models are generally able to provide an acceptable representation of the catchment behaviour, this representation is necessarily simplified and imperfect, as a consequence an evaluation of uncertainties is desirable. This thesis focuses on the quantification of predictive uncertainty in hydrological modelling. Our main objective was to explore several methods that can be used to complete the deterministic predictions of a rainfall-runoff model with probabilistic distributions. Two prediction cases were distinguished, namely simulation and forecast. We set up a comparative framework to evaluate different uncertainty quantification methods on a large set of French catchments. In simulation mode, we focused on two methods related to the parameter estimation issue, the GLUE uncertainty method and the Bayesian framework, as well as two more pragmatic approaches, a multi-model approach and the post-processing method. Our results suggest that the GLUE-like methods based on ensembles of various parameter sets do not provide an adequate representation of the total predictive uncertainty. An external model error is necessary. Post-processing methods that are flexible enough to adequately describe the residual errors of the hydrological model obtained during calibration give more satisfactory estimates of the modelling uncertainty. We also present a method able to transfer model uncertainty estimates from gauged to ungauged catchments. Our results demonstrate that the method holds interesting perspectives, providing in most cases reliable and sharp uncertainty bounds at ungauged locations. In a forecasting context, we compared several post-processing methods and evaluated the interactions between data assimilation and post-processing in an ensemble forecasting modelling chain. Results show the crucial role of the lead time on the estimates of predictive uncertainty. They also suggest that some improvement can be achieved when the evolution of flows is better taken into account by a post-processing method. Last, we investigated the interactions between data assimilation and post-processing in hydrological ensemble forecasting and showed the benefits of using both in an ensemble forecast system

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Hu, Zhengyu, and D. Phillip Guertin. "The Effect of GIS Database Grid Size on Hydrologic Simulation Results." Arizona-Nevada Academy of Science, 1991. http://hdl.handle.net/10150/296461.

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From the Proceedings of the 1991 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 20, 1991, Northern Arizona University, Flagstaff, Arizona The use of geographic information systems (GIS) for assessing the hydrologic effects of management is increasing. In the near future most of our spatial or "mapped" information will come from GIS. The direct linkage of hydrologic simulation models to GIS should make the assessment process more efficient and powerful, allowing managers to quickly evaluate different landscape designs. This study investigates the effect the resolution of GIS databases have on hydrological simulation results from an urban watershed. The hydrologic model used in the study was the Soil Conservation Service Curve Number Model which computes the volume of runoff from rainfall events. A GIS database was created for High School Wash, a urban watershed in Tucson, Arizona. Fifteen rainfall-runoff events were used to test the simulation results. Five different grid sizes, ranging from 25x25 square feet to 300x300 square feet were evaluated. The results indicate that the higher the resolution the better the simulation results. The average ratio of simulated over observed runoff volumes ranged from 0.98 for the 25x25 square feet case to 0.43 for the 300x300 square feet case.

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22

Tondu, Yohann. "Simulation of the Paris 1910 flood with a lumped hydrological model: the influence of frozen soil." Thesis, KTH, Vattendragsteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96310.

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In 1910, Paris experienced its biggest flood in the 20th century. In 2010, for the anniversary of this event – supposed to happen every 100 years ! – the flood prediction model that is now used on the Seine basin was tested on its simulation,… and failed to reproduce the observed flood volume. This paper will try to explain, and correct, such disappointing results. Many hypotheses have been tested and based on their results, it has been decided to develop a frost module in order to assess the influence of this phenomenon – that is not taken into account by the lumped hydrological model that is used – on the flood formation. A soil temperature model using air temperature as input data was also designed because soil temperature data were not available in 1910. The addition of the frost module did not, however, bring many improvements to the 1910 flood simulation because frost is a too rare phenomenon on the Seine basin for the module to be correctly calibrated. However, new perspectives are presented to continue the research on this phenomenon.

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Götzinger, Jens [Verfasser]. "Distributed conceptual hydrological modelling : simulation of climate, land use change impact and uncertainty analysis / von Jens Götzinger." Stuttgart : Inst. für Wasserbau, 2007. http://d-nb.info/996792422/34.

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Fang, Zhufeng [Verfasser]. "3D hydrological simulation of a forested headwater catchment: Spatio-temporal validation and scale dependent parameterization / Zhufeng Fang." Bonn : Universitäts- und Landesbibliothek Bonn, 2016. http://d-nb.info/1119888891/34.

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Abdelnour, Alex Gabriel. "Assessing ecosystem response to natural and anthropogenic disturbances using an eco-hydrological model." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42899.

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The impact of natural and anthropogenic disturbances on catchment hydrological and biogeochemical dynamics are difficult or impossible to capture through experimentation or observation alone. Process-based simulation models can address this need by providing a framework for synthesizing data describing catchment responses to climate, harvest, fire, and other disturbances. However, existing models are either too simple to capture important process-level hydrological and biogeochemical controls on ecosystem responses to disturbance, or are too computationally expensive to simulate the local dynamics over large watershed areas, or require a high level of expertise to implement. To this end, a spatially distributed, physically based, eco-hydrological model (VELMA: Visualizing Ecosystems for Land Management Assessments) that is both computationally efficient and relatively easy to implement is developed. VELMA is a state-of-the-art model with real-time visualization tools that shows temporal and spatial patterns of state and flux variables, and is used to address the effects of changes in climate, land-use, and other interacting stressors on multiple ecosystem services such as timber production, carbon sequestration, regulation of water quality and quantity and reduction of greenhouse gases at scales relevant to formulating management decisions. In this study, VELMA was applied to the H.J. Andrews Experimental forest, an intensively studied watershed with observed daily temperature, precipitation, streamflow, and nutrient losses data. VELMA was first used to explore the factors that controls catchment response to forest harvest. Specifically, elucidate how forest harvest factors such as harvest location and amount control watershed hydrological and biogeochemical fluxes. Thereafter, VELMA was used to reconstruct and analyze the impact of two significant disturbance events − a stand replacing fire and a 100% clearcut − on vegetation and soil carbon and nitrogen dynamics. Finally, VELMA was used to explore the potential impact of climate change on catchment hydrological regime, site productivity and carbon and nitrogen dynamics at high spatial resolution relevant to formulating management decision. The main insights from this study include: (1) streamflow, nutrient losses to the stream, and gaseous carbon and nitrogen losses to the atmosphere are strongly sensitive to the location of harvest as a result of the spatial variation in soil water content, plant nitrogen uptake, soil organic carbon decomposition, nitrification, and denitrification within the watershed, (2) forested riparian buffers reduce water and nutrient losses to the stream through plant transpiration, plant nitrogen uptake, soil storage, and soil microbial decomposition, (3) following fire and harvest, losses of N from the terrestrial system to the stream are tightly constrained by the hydrological cycle and driven mainly by wet-season rain events large enough to generate hydrologic connectivity and flushing of nutrients along hillslopes, (4) climate change strongly impacts the hydrological regime in the Pacific Northwest as a result of less snowpack, earlier snowmelt, higher winter streamflow, lower summer streamflow, and soil moisture deficit, and (5) climate change increases plant and soil biomass accumulation as a result of longer growing season and higher soil organic decomposition, reduce water quality by increasing the amount of nutrients that reach the stream, and transforms the ecosystem into a net source of carbon to the atmosphere.

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Lacombe, Guillaume, Olivier Ribolzi, Rouw Anneke de, et al. "Contradictory hydrological impacts of afforestation in the humid tropics evidenced by long-term field monitoring and simulation modelling." COPERNICUS GESELLSCHAFT MBH, 2016. http://hdl.handle.net/10150/618979.

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The humid tropics are exposed to an unprecedented modernisation of agriculture involving rapid and mixed land-use changes with contrasted environmental impacts. Afforestation is often mentioned as an unambiguous solution for restoring ecosystem services and enhancing biodiversity. One consequence of afforestation is the alteration of streamflow variability which controls habitats, water resources, and flood risks. We demonstrate that afforestation by tree planting or by natural forest regeneration can induce opposite hydrological changes. An observatory including long-term field measurements of fine-scale land-use mosaics and of hydrometeorological variables has been operating in several headwater catchments in tropical southeast Asia since 2000. The GR2M water balance model, repeatedly calibrated over successive 1-year periods and used in simulation mode with the same year of rainfall input, allowed the hydrological effect of land-use change to be isolated from that of rainfall variability in two of these catchments in Laos and Vietnam. Visual inspection of hydrographs, correlation analyses, and trend detection tests allowed causality between land-use changes and changes in seasonal streamflow to be ascertained. In Laos, the combination of shifting cultivation system (alternation of rice and fallow) and the gradual increase of teak tree plantations replacing fallow led to intricate streamflow patterns: pluri-annual streamflow cycles induced by the shifting system, on top of a gradual streamflow increase over years caused by the spread of the plantations. In Vietnam, the abandonment of continuously cropped areas combined with patches of mix-trees plantations led to the natural re-growth of forest communities followed by a gradual drop in streamflow. Soil infiltrability controlled by surface crusting is the predominant process explaining why two modes of afforestation (natural regeneration vs. planting) led to opposite changes in streamflow regime. Given that commercial tree plantations will continue to expand in the humid tropics, careful consideration is needed before attributing to them positive effects on water and soil conservation.

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VanderKwaak, Joel E. "Numerical simulation of flow and chemical transport in integrated surface-subsurface hydrologic systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0012/NQ38276.pdf.

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Fassnacht, Steven Richard. "Distributed snowpack simulation using weather radar with an hydrologic-land surface scheme model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ51194.pdf.

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Bogati, Rabin 1954. "A simulation model to assess the hydrologic perforance of the Tinau watershed, Nepal." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/191891.

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A physical event-based computer methodology is presented for evaluating the hydrologic performance of the Tinau watershed in Nepal. A stochastic model of the seasonal precipitation was developed and used to generate long-term daily synthetic rainfall data. Storm systems in the monsoon months of JUNE through SEPTEMBER are treated as frontal systems, and the storms of the remaining months of the year as independent thunderstorm events. A fitted-parameter conceptual model, called a generalized streamflow simulation system (GSSS), is used to simulate long baseflow recessions. The GSSS model transforms the synthetic rainfall data into daily streamflow using a soil moisture accounting process in a physically consistent manner. The computer output from the model consists of statistics and cumulative density functions for monthly, seasonal and annual discharges, maximum daily high and low flows, and consecutive days of low baseflow. The model output can be used by decision makers to meet the objectives of proper land use and development.

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Bosley, II Eugene Kern. "Hydrologic Evaluation of Low Impact Development Using a Continuous, Spatially-Distributed Model." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/34263.

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Low Impact Development (LID) is gaining popularity as a solution to erosion, flooding, and water quality problems that stormwater ponds partially address. LID analysis takes a spatially lumped approach, based on maintaining the predevelopment Curve Number and time of concentration, precluding consideration of the spatial distribution of impervious areas and Integrated Management Practices (IMPâ s), runoff-runon processes, and the effects of land grading. Success is thus dependent on the accuracy of the assumption of watershed uniformity, applied to both land cover distribution and flow path length. Considering the cost of long-term paired watershed monitoring, continuous, spatially-distributed hydrologic modeling was judged a better method to compare the response of LID, forest, and conventional development. Review of available models revealed EPA-SWMM 4.4H as the most applicable to the task. A 4.3-acre subwatershed of a local subdivision was adapted to LID using impervious surface disconnection, forest retention, and IMPâ s. SWMM was applied to the LID development at a fine spatial scale, yielding an 80-element SWMM model. The LID model was modified to reflect conventional development, with gutters, storm sewer, and detention. A predevelopment forest model was also developed. Two parameter sets were used, representing a range of assumptions characterized as favorable or unfavorable toward a particular development form. Modeled scenarios included favorable and unfavorable versions of Forest, LID, uncontrolled Conventional Development, and Conventional Development with Stormwater Management. SWMM was run in continuous mode using local rainfall data, and event mode using NRCS design storms. Runoff volumes, peak flows, and flow duration curves were compared. Master of Science

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Garcia, Luis Jimenez, Guzman Osnar Iruri, and Sissi Santos Hurtado. "Hazard map based on the simulation of sludge flow in a two-dimensional model, Case Quebrada Malanche-Punta Hermosa -Lima-Perú." Institute of Electrical and Electronics Engineers Inc, 2020. http://hdl.handle.net/10757/656417.

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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. This research presents the numerical simulation to reproduce the transport and deposition processes of the sludge flow on March 15, 2017, strongly impacting the town of Pampapacta in Punta Hermosa-Peru.The debris flow initiation process in the basin was represented by hydrographs obtained from the estimated volumes of stormwater runoff and solid materials. The sludge flow was modeled in Flo2D to calculate hazard maps with the discharge event and others with different return periods.The numerical simulation results show acceptable results in relation to what happened. The model used to assess the hazard due to debris flow can predict and delineate, with acceptable precision, potentially hazardous areas for a landslide. The application of the proposed methodology to assess the hazard of disasters due to debris flows in basins and streams is useful to understand the extent of the impact of the mud flow during extreme weather events, as well as to develop emergency plans and formulate disaster policies.

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Zhang, Xiaohui. "Integration of a stochastic space-time rainfall model and distributed hydrologic simulation with GIS." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282409.

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This research presents an integration of a stochastic space-time rainfall model and distributed hydrologic simulation with GIS. The integrated simulation system consists of three subsystems: a stochastic space-time rainfall model, a geographical information system (GIS), and a distributed physically-based hydrologic model. The developed stochastic space-time rainfall model is capable of estimating the storm movement and simulating a random rainfall field over a study area, based on the measurement from three raingauges. An optimization-based lag-k correlation method was developed to estimate the storm movement, and a stochastic model was developed to simulate the rainfall field. A GIS tool, ARC/INFO, was integrated into this simulation system. GIS has been applied to automatically extract the spatially distributed parameters for hydrologic modeling. Digital elevation modeling techniques were used to process a high resolution digital map. A distributed physically-based hydrologic model, operated in HEC-1, simulated the stochastic, distributed, interrelated hydrological processes. The Green-Ampt equation is used for modeling the infiltration process, kinematic wave approximation for infiltration-excess overland flow, and the diffusion wave model for the unsteady channel flow. Two small nested experimental watersheds in southern Arizona were chosen as the study area where three raingauges are located. Using five recorded storm events, a series of simulations were performed under a variety of conditions. The simulation results show the model performs very well, by comparing the simulated runoff peak flow and runoff depth with the measured ones, and evaluated by the model efficiency. Both model structure and model parameter uncertainties were investigated in the sensitivity analysis. The statistical tests for the simulation results show that it is important to model stochastic rainfall with storm movement, which caused a significant change in runoff peak flow and runoff depth from that where the input is only one gage data. The sensitivity of runoff to roughness factor N and hydraulic conductivity Ks were intensively investigated. The research demonstrated this integrated system presents an improved simulation environment for the distributed hydrology.

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Bounhieng, Vilaysane. "INTEGRATED IMPACT ASSESSMENT OF CLIMATE CHANGE ON HYDROLOGY OF THE XEDONE RIVER BASIN, LAO PDR." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/204586.

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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.

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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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Kautz, Mark Anderson, and Mark Anderson Kautz. "Hydrologic Model Parameterization Using Dynamic Landsat-Based Foliar Cover Estimates for Runoff Simulation on a Semiarid Grassland Watershed." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/622850.

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Changes in watershed vegetative cover from natural and anthropogenic causes including, climatic fluctuations, wildfires and land management practices, can result in increased surface water runoff and erosion. Hydrologic models play an important role in the decision support process for managing these landscape alterations. However, model parameterization requires quantified measures of watershed biophysical condition to generate accurate results. These inputs are often obtained from nationally available land cover data sets that are static in terms of vegetation condition and phenology. Obtaining vegetative data for model input of sufficient spatiotemporal resolution for long-term, watershed-scale change analysis has been a challenge. The purpose of this research was to assess the implications of parameterizing the event-based, Rangeland Hydrology and Erosion Model (RHEM) with dynamic, remotely sensed foliar cover data. The study was conducted on a small, instrumented, grassland watershed within the Walnut Gulch Experimental Watershed surrounding Tombstone, Arizona. A time series of foliar cover rasters was produced by calibrating Landsat-based Soil Adjusted Total Vegetation Index (SATVI) scenes with field measurements. Estimates of basal and litter cover were calculated using allometric relationships derived from ground-based transect data. The model was parameterized using these remotely sensed inputs for all recorded runoff events from 1996-2014. Model performance was improved using the remotely sensed foliar cover compared to using an a priori value based on static national land cover classes. Significant (p<0.05) correlation was shown for the linear relationships between foliar cover and SATVI, foliar cover and basal cover, and foliar cover and litter cover. The integration of Landsat-based vegetative data into RHEM shows potential for modelling on a broadened spatiotemporal scale, allowing for improved landscape characterization and the ability to track watershed response to long-term vegetation changes.

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Fabbiani-Leon, Angelique Marie. "Comparison method between gridded and simulated snow water equivalent estimates to in-situ snow sensor readings." Thesis, University of California, Davis, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1604056.

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California Department of Water Resources (DWR) Snow Surveys Section has recently explored the potential use of recently developed hydrologic models to estimate snow water equivalent (SWE) for the Sierra Nevada mountain range. DWR Snow Surveys Section’s initial step is to determine how well these hydrologic models compare to the trusted regression equations, currently used by DWR Snow Surveys Section. A comparison scheme was ultimately developed between estimation measures for SWE by interpreting model results for the Feather River Basin from: a) National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) gridded SWE reconstruction product, b) United States Geological Survey (USGS) Precipitation-Runoff Modeling System (PRMS), and c) DWR Snow Surveys Section regression equations. Daily SWE estimates were extracted from gridded results by computing an average SWE based on 1,000 ft elevation band increments from 3,000 to 10,000 ft (i.e. an elevation band would be from 3,000 to 4,000 ft). The dates used for processing average SWE estimates were cloud-free satellite image dates during snow ablation months, March to August, for years 2000–2012. The average SWE for each elevation band was linearly interpolated for each snow sensor elevation. The model SWE estimates were then compared to the snow sensor readings used to produce the snow index in DWR’s regression equations. In addition to comparing JPL’s SWE estimate to snow sensor readings, PRMS SWE variable for select hydrologic response units (HRU) were also compared to snow sensor readings. Research concluded with the application of statistical methods to determine the reliability in the JPL products and PRMS simulated SWE variable, with results varying depending on time duration being analyzed and elevation range.

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Phoon, Syin Yi. "Application of global circulation model results on hydrological conceptual models that simulate future river flows feeding Lake Victoria, East Africa." Thesis, University of Birmingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443641.

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Galletti, Andrea. "Detailed simulation of storage hydropower systems in the Italian Alpine Region." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/266707.

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The water-energy nexus holds paramount relevance in the context of the transition to a carbon free energy system, being water the only renewable energy source with reliable storage capacity. Modelling hydropower production in a large domain over a long time window represents an open challenge due to a variety of reasons: firstly, high-resolution, large-scale hydrological modelling in a context of uncertainty needs calibration, thus representing a computationally intensive task due to the large domain and time window over which calibration is needed; secondly, as stated by many works in literature, hydropower production modelling and in particular reservoir modelling is a very information-demanding procedure, and excessive simplifications adopted to face the lack of information might lead to consistent bias in the predictions. This thesis can be subdivided into three main parts: firstly, the model that was used to perform every analysis, HYPERstreamHS, will be presented. The model is a continuous, large-scale hydrological model embedding a dual-layer MPI framework (i.e. Message Passing Interface, a common standard in parallel computing) that ensures optimal scalability of the model, greatly reducing the computation time needed. Explicit simulation of water diversions due to hydropower production is also included in the model, and adopts only publicly available information, making the model widely applicable. Secondly, a first validation of the model will be presented, and the adopted approach will be compared with some other approaches commonly found in literature, showing that the inclusion of a high level of detail is crucial to ensure a reliable performance of the model; this first application was performed on the Adige catchment, where extensive information on human systems was available, and allowed to effectively assess which information were indispensable and which, in turn, could be simplified to some extent while preserving model performance. Finally, the model setup has been applied on a relevant portion of the Western Italian Alps; in this case, two different meteorological input forcing data sets were adopted, in order to assess the differences in their performance in terms of hydropower production modelling. This latter study indeed represents a preliminary analysis and will provide stepping stone to extend the modelling framework to the Italian Alpine Region.

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Surur, Anwar. "Simulated Impact of Land Use Dynamics on Hydrology during a 20-year-period of Beles Basin in Ethiopia." Thesis, KTH, Land and Water Resources Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-13257.

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Land use/cover has shown significant changes during the past three decades in Ethiopia especially in the highlands of the country. That resulted in changes in streamflows and other hydrological processes. The existing land and water resources system of the area is adversely affected due the rapid growth of population, deforestation, surface erosion and sediment transport. The main objective of this study is to evaluate the impact of land use/cover changes in the hydrology of Beles Basin, Ethiopia. The physically based hydrologic model, SWAT, was developed for the Beles basin, Ethiopia by combining geospatial and climatic data. ArcGIS has been used to process geospatial data which includes the Digital Elevation Model (DEM) which has a resolution of 90 m, land use/cover and soil maps. A simple Interpolation technique has been used to fill in the missing precipitation data. The GIS interface version of SWAT (ArcSWAT) has the capability to utilize ArcGIS to facilitate input data preparation and output data generation. Idrisi Andes in cooperation with ArcGIS 9.2 used to generate landuse/cover maps from Landsat data of three different years. Three SWAT models were set up using the three generated land use/cover maps and used to evaluate the land use/cover change and its impacts on the streamflow of study basin. The primary hydrological model was evaluated through sensitivity analysis, model calibration, and model validation for realistic prediction of the different hydrological components in the basin. Out of twenty six flow parameters sixteen parameters were found to be sensitive. But the most sensitive ten parameters were selected and used for model calibration. The model calibration was carried out using observed streamflow data from 01 January 2001 to 31 December 2002 and a validation period from 01 January 2003 to 31 December 2004. The coefficient of determinations (R2) was 0.74 and the Nash-Sutcliffe simulation efficiency (NSE) was 0.62which indicated that the model was able to predict streamflow with reasonable accuracy. However, the hydrograph of the cumulative hydrographs of the calibration and validation periods showed significant discrepancies between the observed and the simulated data of each period. The average yearly flow volume of the observed streamflow on the cumulative hydrograph of the calibration period has exceeded the simulated streamflow. On the other hand on the cumulative hydrograph of the validation period the average yearly flow volume of the simulated streamflow was higher than the observed streamflow. The simulated result of the streamflow data from different land use/cover maps revealed that the change in the land use/cover classes of the basin throughout the study periods. QC 20100707

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Oliveira, Cristiano de Pádua Milagres. "Plataforma de análise e simulação hidrológica - PLASH." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3147/tde-15052014-162931/.

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A modelagem matemática da hidrologia de bacias hidrográficas é largamente utilizada em estudos de diversos tipos de problemas encontrados na engenharia hidráulica e de recursos hídricos. Nestes últimos 150 anos, muitos pesquisadores realizaram observações e experimentos sobre a natureza do ciclo hidrológico para que pudessem entender e equacionar seu comportamento. Diversos modelos diferentes surgiram baseando-se em equacionamentos físicos e empíricos, sendo que muitos destes modelos clássicos são utilizados até hoje. Para se ter uma visão mais abrangente do tema, uma revisão do estado da arte é apresentada, com uma perspectiva histórica destes modelos e seus criadores, assim como uma classificação fundamentada em suas características. Também são examinados alguns dos sistemas computacionais para modelagem hidrológica de bacias hidrográficas mais utilizados atualmente. São discutidas as hipóteses de uma simplificação do ciclo hidrológico para eventos intensos utilizados em projetos. Cada componente do ciclo hidrológico simplificado é modelado utilizando um dos diferentes modelos hidrológicos propostos, com graus de complexidade distintos. Para cada um destes modelos é realizada uma análise de sensibilidades dos seus parâmetros. Baseado nos avanços tecnológicos mais recentes na ciência da computação foi desenvolvido, em paralelo a esta pesquisa, uma ferramenta computacional que compila todos os conceitos aqui apresentados e tem distribuição acadêmica livre. The mathematical modeling of the watershed hydrology is widely used in studies of several problems related to hydraulic and water resources engineering. On these last 150 years, many researchers accomplished observations and experiments on the nature of the hydrologic cycle in order to understand and equates its behavior. Several different models appeared basing on physical and empiric equating, and many of these classic models are being used until today. To get a more comprehensive view on the theme, a state of the art revision is presented, with an historical perspective about these models and its creators, such as a classification based on its characteristics are presented. Also some computational systems of hydrologic modeling of watershed are also examined more used now. The hypotheses of a simplification of the hydrologic cycle are discussed for intense events used in projects. Each component of the simplified hydrologic cycle is modeled using one of the different hydrologic models proposed, with distinct grades of complexity. For each one of these models a sensibility analysis of their parameter is performed. Based on the more recent technological progresses in the computational science was developed, parallel to this research, a computational tool that compiles all the concepts here presented and has free academic distribution.

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41

Rawal, Kishor. "Exploring the Geomechanics of Sinkholes: A Preliminary Numerical Study." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1480069621108946.

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42

Ranatunga, Thushara D. "Simulation of Watersheds Hydrology under Different Hydro-Climatic Settings." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1421925170.

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43

Souza, Danilo Nogueira de. "AnÃlise do processo de amortecimento de cheias em reservatÃrios: parÃmetros intervenientes e proposta de mÃtodo de estimativa." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12758.

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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico O amortecimento de ondas de cheias se constitui em uma caracterÃstica fundamental dos reservatÃrios superficiais, uma vez que tem impacto direto na prÃpria seguranÃa da barragem, afetando as outras funÃÃes do aÃude. Logo, se esta caracterÃstica nÃo for suficientemente eficiente para atenuar os picos de vazÃes afluentes, hÃ o sÃrio risco de ocorrÃncia de âgalgamentoâ; ou seja, a altura da lÃmina dâÃgua vertida supera o valor mÃximo admitido em projeto, levando a um possÃvel rompimento da estrutura da barragem. Muitos reservatÃrios superficiais encontram-se envelhecidos e fora das normas tÃcnicas atuais, sendo preocupante a situaÃÃo no Estado do CearÃ, no qual vÃrias barragens foram construÃdas hÃ mais de meio sÃculo. Tal fato Ã especialmente importante, dado que estes reservatÃrios desempenham mÃltiplas funÃÃes. Assim, para garantir que os padrÃes mÃnimos de seguranÃa das barragens brasileiras sejam atendidos, foi aprovada a Lei de Barragens em 2010. Esta lei surgiu como resposta, assim como em muitos paÃses, Ã ocorrÃncia de expressivos tipos de acidentes em barragens; entre eles, os decorrentes de âgalgamentoâ. Logo, para que o processo de amortecimento de ondas de cheias afluentes aos aÃudes do semiÃrido seja mais detalhado, foram realizadas simulaÃÃes hidrolÃgicas de vÃrios cenÃrios representativos de configuraÃÃes de reservatÃrios e de bacias hidrogrÃficas atravÃs da variaÃÃo dos parÃmetros originais de um reservatÃrio teste (AÃude JoÃo Guerra). Como resultado, determinou-se o impacto de cada parÃmetro fÃsico adimensional e de cada variÃvel no amortecimento. Estes parÃmetros foram agregados em um Ãnico Ãndice, em cuja funÃÃo foi proposto um mÃtodo grÃfico expedito fÃcil para estimar do amortecimento, segundo diversos valores de precipitaÃÃo. O presente estudo revelou ainda que o amortecimento decamilenar, a partir de uma dada fraÃÃo de chuva, pode ser aproximado pelo amortecimento milenar, e o mÃtodo Ã mais sensÃvel Ã variaÃÃo do fator de forma do reservatÃrio do que Ãs variaÃÃes das outras variÃveis. Flood damping constitutes a fundamental characteristic of surface reservoirs, because it has direct impact on the safety of the dam itself, affecting other functions of the dam. So, if this feature is not efficient enough to attenuate the peak inflow, there is a serious risk of occurrence of "overtoppingâ; in other words, the height of the poured water exceeds the maximum value allowed in the project. Many surface reservoirs are getting old and out of the current technical standards, being worrying the situation in the State of CearÃ, in which several dams were built more than half a century ago. This fact is particularly important, given that these reservoirs play multiple roles. Thus, to ensure that brazilians damsâ minimum safety standards are met, The Dams Act was approved in 2010. This law appeared in response, as in many countries, to the occurrence of significant types of accidents, including the ones resulting from âovertoppingâ. Therefore, in order to more detail the process of flood damping in semiarid reservoirs, hydrological simulations were performed for several scenarios that represent settings of reservoirs and watersheds through the variation of the original parameters of a test reservoir (JoÃo Guerra Dam). As a result, it was determined the weight of each dimensionless physical parameter and each variable in the flood damping. These parameters were aggregated into a single index, in whose function it was proposed an easy expeditious graphical method in order to estimate the flood damping, according to different values of precipitation. This study also revealed that the decamillennial damping, from a given fraction of precipitation, can be approximated by the millennial damping, and the method is more sensitive to the variation of the form factor of the reservoir than to the variations of the other variables.

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44

Cunha, Luciana Kindl da. "Exploring the benefits of satellite remote sensing for flood prediction across scales." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/2848.

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Space-borne remote sensing datasets have the potential to allow us to progress towards global scale flood prediction systems. However, these datasets are limited in terms of space-time resolution and accuracy, and the best use of such data requires understanding how uncertainties propagate through hydrological models. An unbiased investigation of different datasets for hydrological modeling requires a parsimonious calibration-free model, since calibration masks uncertainties in the data and model structure. This study, which addresses these issues, consists of two parts: 1) the development and validation of a multi-scale distributed hydrological model whose parameters can be directly linked to physical properties of the watershed, thereby avoiding the need of calibration, and 2) application of the model to demonstrate how data uncertainties propagate through the model and affect flood simulation across scales. I based the model development on an interactive approach for model building. I systematically added processes and evaluated their effects on flood prediction across multiple scales. To avoid the need for parameter calibration, the level of complexity in representing physical processes was limited by data availability. I applied the model to simulate flows for the Cedar River, Iowa River and Turkey River basins, located in Iowa. I chose this region because it is rich in high quality hydrological information that can be used to validate the model. Moreover, the area is frequently flooded and was the center of an extreme flood event during the summer of 2008. I demonstrated the model's skills by simulating medium to high-flow conditions; however the model's performance is relatively poor for dry (low flow) conditions. Poor model performance during low flows is attributed to highly nonlinear dynamics of soil and evapotranspiration not incorporated in the model. I applied the hydrological model to investigate the predictability skills of satellite-based datasets and to investigate the model's sensibility to certain hydro-meteorological variables such as initial soil moisture and bias in evapotranspiration. River network structure and rainfall are the main components shaping floods, and both variables are monitored from space. I evaluated different DEM sources and resolution DEMs as well as the effect of pruning small order channels to systematically decreasing drainage density. Results showed that pruning the network has a greater effect on simulated peak flow than the DEM resolution or source, which reveals the importance of correctly representing the river network. Errors on flood prediction depend on basin scale and rainfall intensity and decrease as the basin scale and rainfall intensity increases. In the case of precipitation, I showed that simulated peak flow uncertainties caused by random errors, correlated or not in space, and by coarse space-time data resolution are scale-dependent and that errors in hydrographs decrease as basin scale increases. This feature is significant because it reveals that there is a scale for which less accurate information can still be used to predict floods. However, the analyses of the real datasets reveal the existence of other types of error, such as major overall bias in total volumes and the failure to detect significant rainfall events that are critical for flood prediction.

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Zarekarizi, Mahkameh. "Ensemble Data Assimilation for Flood Forecasting in Operational Settings: from Noah-MP to WRF-Hydro and the National Water Model." PDXScholar, 2018. https://pdxscholar.library.pdx.edu/open_access_etds/4651.

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The National Water Center (NWC) started using the National Water Model (NWM) in 2016. The NWM delivers state-of-the-science hydrologic forecasts in the nation. The NWM aims at operationally forecasting streamflow in more than 2,000,000 river reaches while currently river forecasts are issued for 4,000. The NWM is a specific configuration of the community WRF-Hydro Land Surface Model (LSM) which has recently been introduced to the hydrologic community. The WRF-Hydro model, itself, uses another newly-developed LSM called Noah-MP as the core hydrologic model. In WRF-Hydro, Noah-MP results (such as soil moisture and runoff) are passed to routing modules. Riverine water level and discharge, among other variables, are outputted by WRF-Hydro. The NWM, WRF-Hydro, and Noah-MP have recently been developed and more research for operational accuracy is required on these models. The overarching goal in this dissertation is improving the ability of these three models in simulating and forecasting hydrological variables such as streamflow and soil moisture. Therefore, data assimilation (DA) is implemented on these models throughout this dissertation. State-of-the art DA is a procedure to integrate observations obtained from in situ gages or remotely sensed products with model output in order to improve the model forecast. In the first chapter, remotely sensed satellite soil moisture data are assimilated into the Noah-MP model in order to improve the model simulations. The performances of two DA techniques are evaluated and compared in this chapter. To tackle the computational burden of DA, Massage Passing Interface protocols are used to augment the computational power. Successful implementation of this algorithm is demonstrated to simulate soil moisture during the Colorado flood of 2013. In the second chapter, the focus is on the WRF-Hydro model. Similarly, the ability of DA techniques in improving the performance of WRF-Hydro in simulating soil moisture and streamflow is investigated. The results of chapter 2 show that the assimilation of soil moisture can significantly improve the performance of WRF-Hydro. The improvement can reach 58% depending on the study location. Also, assimilation of USGS streamflow observations can improve the performance up to 25%. It was also observed that soil moisture assimilation does not affect streamflow. Similarly, streamflow assimilation does not improve soil moisture. Therefore, joint assimilation of soil moisture and streamflow using multivariate DA is suggested. Finally, in chapter 3, the uncertainties associated with flood forecasting are studied. Currently, the only uncertainty source that is taken into account is the meteorological forcings uncertainty. However, the results of the third chapter show that the initial condition uncertainty associated with the land state at the time of forecast is an important factor that has been overlooked in practice. The initial condition uncertainty is quantified using the DA. USGS streamflow observations are assimilated into the WRF-Hydro model for the past ten days before the forecasting date. The results show that short-range forecasts are significantly sensitive to the initial condition and its associated uncertainty. It is shown that quantification of this uncertainty can improve the forecasts by approximately 80%. The findings of this dissertation highlight the importance of DA to extract the information content from the observations and then incorporate this information into the land surface models. The findings could be beneficial for flood forecasting in research and operation.

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46

Sehgal, Vinit. "Near Real-time Seasonal Drought Forecasting and Retrospective Drought Analysis using Simulated Multi- layer Soil Moisture from Hydrological Models at Sub- Watershed Scales." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78623.

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This study proposes a stratified approach of drought severity assessment using multi-layer simulated soil moisture. SWAT (Soil and Water Assessment Tool) models are calibrated for 50 watersheds in the South-Atlantic Gulf region of the Southeastern US and a high-resolution daily soil moisture dataset is obtained at Hydrologic Unit Code (HUC-12) resolution for a period of January 1982 through December 2013. A near real-time hydrologic simulation framework by coupling the calibrated SWAT models with the National Centers for Environmental Prediction (NCEP) coupled forecast system model version 2 (CFSv2) weather data is developed to forecast various water balance components including soil moisture (SM), actual evapotranspiration (ET), potential evapotranspiration ET (PET), and runoff (SURQ) for near-real time drought severity assessment, and drought forecasting for a lead of 9-months. A combination of the surface and total rooting depth soil moisture percentiles proves to be an effective increment over conventional drought assessment approaches in capturing both, transient and long-term drought impacts. The proposed real-time drought monitoring approach shows high accuracy in capturing drought onset and propagation and shows a high degree of similarity with the U.S. Drought Monitor (USDM), the long-term (PDSI, PHDI, SPI-9 and SPI-12), and the short-term (Palmer Z index, SPI-1 and SPI-6) drought indices. Master of Science

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47

Safaei, Jazi Ramin. "Simulation of Groundwater Flow System in Sand-Lick Watershed, Boone County, West Virginia (Numerical Modeling Approach)." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1375983541.

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Bayer, Débora Missio. "Efeitos das mudanças de uso da terra no regime hidrológico de bacias de grande escala." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/95694.

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Os efeitos das alterações de uso da terra na hidrologia das bacias hidrográficas têm sido, ao longo dos anos, amplamente discutidos para pequenas bacias experimentais. O uso de modelos hidrológicos para descrever esse tipo de processo tem se tornado promissor no que tange o estudo de grandes bacias. Sendo assim, o objetivo deste trabalho é avaliar uma metodologia para analisar o impacto das mudanças de uso da terra sobre o regime hidrológico em bacias hidrográficas de grande escala. Este estudo foi realizado por meio de simulação. Para isso foi utilizado um modelo hidrológico distribuído de base física, o Modelo de Grandes Bacias (MGB-IPH). Para realizar simulações de impactos das mudanças de uso da terra, inicialmente avaliou-se a capacidade do modelo MGB-IPH de captar as alterações produzidas pelas mudanças de uso. A análise de sensibilidade mostrou que a vazão gerada na bacia é inversamente proporcional aos parâmetros de índice de área foliar (IAF) e de altura média da vegetação (h), uma vez que quanto maior o IAF, mais interceptação ocorrerá na bacia e, quanto maior o valor de h, mais facilidade haverá nas trocas aerodinâmicas, ambos favorecendo o processo de evaporação. Já em relação aos parâmetros albedo (a) e resistência superficial (rs), a vazão gerada é diretamente proporcional, pois quanto maior o a maior a energia refletida pela superfície e, consequentemente menos energia estará disponível para o processo de evaporação. Em relação à rs, o seu aumento implica em uma menor perda por transpiração, disponibilizando mais água para gerar escoamento. As simulações de análise de sensibilidade mostraram que o MGB-IPH reproduz, de forma coerente, o comportamento médio das bacias submetidas ao desmatamento em um grande número de estudos experimentais. Assim, avaliou-se os impactos das mudanças de uso da terra no regime hidrológico em bacias de grande escala através de um estudo de caso. Este estudo de caso foi realizado na Bacia Hidrográfica do Rio Paraná. Os resultados das simulações mostraram que o desmatamento possui forte influência sobre as variáveis hidrológicas, como interceptação, evapotranspiração e vazão. Devido ao desmatamento foram verificadas reduções na interceptação e na evapotranspiração ao longo dos anos. Em relação a vazão, verificou-se que as simulações foram capaz de captar a não estacionariedade existente nas vazões observadas. Além disso, foi possível verificar que a vegetação pode ser associada a 39% dos incrementos observados na vazão média de longo termo, quando comparados os períodos anterior e posterior a 1970 na Bacia Hidrográfica do Rio Paraná. Já as variações na precipitação são responsáveis por 61% dos impactos na vazão média. Em relação às vazões extremas foram verificados incrementos, sendo eles mais expressivos nas vazões mínimas do que nas vazões máxima. Assim, pode-se afirmar que a metodologia proposta é consistente com os efeitos observados na bacia e com os resultados de estudos experimentais realizados em diferentes regiões do mundo. The effects of land use change on the hydrology of watersheds have been widely discussed during several years in small basins. The hydrological models have been promising for describe the effects of land use change in hydrology in large basins. Thus, the aim of this study was to evaluate a methodology to study the impact of land use changes on the hydrological processes in large basins. This study was conducted by hydrological simulation. For this, a physically based distributed hydrological model, Modelo de Grandes Bacias (MGB-IPH), was used. The ability of MGB-IPH model for study the effects of land-use change in hydrology processes was first analyzed. The results of sensibility analysis showed that the flow generated in the basin is inversely proportional to the parameters of leaf area index (LAI) and average vegetation height (h), since the higher the LAI more interception, and the higher the h easier will be the aerodynamic changes, both favoring the evaporation process . The flow is directly proportional to the parameters albedo (a) and surface resistance (rs), since the greater the a, more energy reflected by the surface, and consequently less energy is available for the evaporation process. The increasing in rs parameter implies a smaller loss by transpiration, and then more runoff is generated. The sensibility analysis showed that the MGB-IPH reproduces consistently, the average behavior of the basins subjected to deforestation on a large number of experimental studies. Thus, we evaluated the impacts of land use changes on the hydrological regime in large-scale basins by a case study. This case study was conducted in the Paraná River Basin. The simulation results showed that deforestation has a strong influence by hydrological variables, such as interception, evapotranspiration and flow. Due to deforestation were observed interception and evapotranspiration reduction over the years. It was found that the simulations were able to capture the non-stationarity in the observed streamflows. Furthermore, we found that 39% of the observed increase in average flow of long term is due to vegetation change, when comparing the periods before and after 1970 in the Paraná River Basin, while the 61% is due precipitation changes. Increments were observed in extreme flows. These increments were more evident at low flows than the maximum flow. Thus, it can be stated that the proposed methodology is consistent with the effects observed in the Rio Paraná basin and with the results of experimental studies conducted in different regions of the world.

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Yang, Heng. "The hydrologic effects of climate change and urbanization in the Las Vegas Wash Watershed, Nevada." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1384334002.

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Thomas, Nicholas Wayne. "Simulating the hydrologic impact of distributed flood mitigation practices, tile drainage, and terraces in an agricultural catchment." Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/2017.

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Abstract:

In 2008 flooding occurred over a majority of Iowa, damaging homes, displacing residents, and taking lives. In the wake of this event, the Iowa Flood Center (IFC) was charged with the investigation of distributed flood mitigation strategies to reduce the frequency and magnitude of peak flows in Iowa. This dissertation is part of the several studies developed by the IFC and focused on the application of a coupled physics based modeling platform, to quantify the coupled benefits of distributed flood mitigation strategies on the reduction of peak flows in an agricultural watershed. Additional investigation into tile drainage and terraces, illustrated the hydrologic impact of each commonly applied agricultural practice. The effect of each practice was represented in numerical simulations through a parameter adjustment. Systems were analyzed at the field scale, to estimate representative parameters, and applied at the watershed scale. The impact of distributed flood mitigation wetlands reduced peak flows by 4 % to 17 % at the outlet of a 45 km2 watershed. Variability in reduction was a product of antecedent soil moisture, 24-hour design storm total depth, and initial structural storage capacity. The highest peak flow reductions occurred in scenarios with dry soil, empty project storage, and low rainfall depths. Peak flow reductions were estimated to dissipate beyond a total drainage area of 200 km2, approximately 2 km downstream of the small watershed outlet. A numerical tracer analysis identified the contribution of tile drainage to stream flow (QT/Q) which varied between 6 % and 71 % through an annual cycle. QT/Q responded directly to meteorological forcing. Precipitation driven events produced a strong positive logarithmic correlation between QT/Q and drainage area. The addition of precipitation into the system saturated near surface soils, increased lateral soil water movement, and reduced the contribution of instream tile flow. A negative logarithmic trend in QT/Q to drainage area persisted in non-event durations. Simulated gradient terraces reduced and delayed peak flows in subcatchments of less than 3 km2 of drainage area. The hydrographs were shifted responding to rainfall later than non-terraced scenarios, while retaining the total volumetric outflow over longer time periods. The effects of dense terrace systems quickly dissipated, and found to be inconsequential at a drainage area of 45 km2. Beyond the analysis of individual agricultural features, this work assembled a framework to analyze the feature at the field scale for implementation at the watershed scale. It showed large scale simulations reproduce field scale results well. The product of this work was, a systematic hydrologic characterization of distributed flood mitigation structures, pattern tile drainage, and terrace systems facilitating the simulation of each practices in a physically-based coupled surface-subsurface model.

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Dissertations / Theses on the topic 'Hydrological simulator'

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