Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Hydrologic Method.
Rozprawy doktorskie na temat „Hydrologic Method”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Hydrologic Method”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Chen, Mi. "Using an integrated linkage method to predict hydrological responses of a mixed land use watershed". Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--Ohio State University, 2003.Title from first page of PDF file. Document formatted into pages; contains xvi, 378 p.; also includes graphics (some col.). Includes bibliographical references (p. 229-252). Available online via OhioLINK's ETD Center
2
Lee, Hyung-Jin. "Regional forecasting of hydrologic parameters". Ohio : Ohio University, 1996. http://www.ohiolink.edu/etd/view.cgi?ohiou1178223662.
Pełny tekst źródła
3
Sun, Jingyun. "Hydrologic and hydraulic model development for flood mitigation and routing method comparison in Soap Creek Watershed, Iowa". Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1914.
Pełny tekst źródłaStreszczenie:
The primary objective of this thesis is to develop hydrologic and hydraulic models for the Soap Creek Watershed, IA for the evaluation of alternative flood mitigation strategies and the analysis of the differences between hydrologic and hydraulic routing methods.
In 2008, the state of Iowa suffered a disastrous flood that caused extensive damage to homes, agricultural lands, commercial property, and public infrastructures. To reduce the flood damage across Iowa, the U.S. Department of Housing and Urban Development (HUD) awarded funds to the Iowa Flood Center and IIHR-Hydroscience &Engineering at the University of Iowa to conduct the Iowa Watersheds Project. The Soap Creek Watershed was selected as one of the study areas because this region has suffered frequent severe floods over the past century and because local landowners have organized to construct over 130 flood detention ponds within it since 1985.
As part of the Iowa Watersheds Project, we developed a hydrologic model using the
U.S. Army Corps of Engineers’ (USACE) Hydrologic Center’s hydrologic Modeling System (HEC-HMS). We used the hydrologic model to evaluate the effectiveness of the existing flood mitigation structures with respect to discharge and to identify the high runoff potential areas. We also investigated the potential impact of two additional flood mitigation practices within the Soap Creek Watershed by utilizing the hydrologic model, which includes changing the land use and improving the soil quality. The HEC-HMS model simulated 24-hour design storms with different return periods, including 10, 25, 50, and 100 year. The results from modeling four design storms revealed that all three practices can reduce the peak discharge at different levels. The existing detention ponds were shown to reduce the peak discharge by 28% to 40% depending on the choice of observed locations and design storms. However, changing the land use can reduce the peak discharge by an average of only 1.0 %, whereas improving the soil quality can result in an average of 15 % reduction.
Additionally, we designed a hydraulic model using the United States Army Corps of Engineers’ (USACE) Hydrologic Engineering Center’s River Analysis System (HEC- RAS) to perform a comparative evaluation of hydrologic and hydraulic routing methods. The hydrologic routing method employed in this study is the Muskingum Routing method. We compare the historical and design storms between HEC-HMS, HEC-RAS, and observed stage hydrographs and take the hydrograph timing, shape, and magnitude into account. Our results indicate that the hydraulic routing method simulates the hydrograph shape more effectively in this case.
4
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.
Pełny tekst źródłaStreszczenie:
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.
5
Dolder, Herman Guillermo. "A Method for Using Pre-Computed Scenarios of Physically-Based Spatially-Distributed Hydrologic Models in Flood Forecasting Systems". BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5676.
Pełny tekst źródłaStreszczenie:
Every year floods are responsible of a significant number of human losses, many of which could be avoided with a broader implementation of flood forecasting systems. Nevertheless, there are still some technological and economic limitations that impede the creation of these systems in many parts of the world. At the core of many flood forecasting systems is a hydrologic model that transforms the weather forecast into a flow forecast. Using real-time modeling for potential floods poses a series of problems: if the model is complex, the computational power required can be significant, and consequently expensive, and if the model is simple enough to run on regular computers in the time allotted, it is likely that the results will not be accurate enough to be useful. I propose the development of a standardized method for using pre-computed scenarios as an alternative to real-time flood modeling. I explain how pre-computing has been used on other realms in the past, and how it is beginning to be implemented in different branches of hydrology, the prediction coastal flooding due to storms or tsunamis being one of the most developed. My research has focused on answering the questions that arise during the design stage of a flood forecasting system not only for rain or snow driven floods, but also by anthropogenic-produced floods. I analyze the number of parameters and their granularity to be used to create the scenarios, the accuracy of the results, different strategies to implement the systems, etc. Finally, I present some test-cases of the application of the method, and assess their results.
6
Zhang, Meijing. "Quantifying high-resolution hydrologic parameters at the basin scale using InSAR and inverse modeling, Las Vegas Valley, NV". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/50833.
Pełny tekst źródłaStreszczenie:
The overall goal of this dissertation is to determine and develop optimal strategies for inversely calibrating transmissivities (T), elastic and inelastic skeletal storage coefficients (Ske and Skv) of the developed-zone aquifer and conductance (CR) of the basin-fill faults for the entire Las Vegas basin, and to investigate future trends of land subsidence in Las Vegas Valley.
This dissertation consists of three separate stand-alone chapters. Chapter 2 presents a discrete adjoint parameter estimation (APE) algorithm for automatically identifying suitable hydraulic parameter zonations from hydraulic head and subsidence measurements. Chapter 3 compares three different inversion strategies to determine the most accurate and computationally efficient method for estimating T and Ske and Skv at the basin scale: the zonation method (ZM), the adaptive multi-scale method and the Differential Evolution Adaptive Metropolis Markov chain Monte Carlo scheme (DREAM MCMC). Chapter 4 outlines a fine-scale numerical model capable of capturing far more hydrologic detail than any previously developed model of Las Vegas Valley The new model is calibrated using high-resolution InSAR data and hydraulic head data from 1912 to 2010. The calibrated model is used to investigate the influence of faults and their potential role on influencing clay thicknesses and land subsidence distributions, and to investigate future trends of land subsidence in Las Vegas Valley.Ph. D.
7
Desai, Ahmed Yacoob. "Development of a hydraulic sub-model as part of a desktop environmental flow assessment method". Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1006200.
Pełny tekst źródłaStreszczenie:
Countries around the world have been developing ecological policies to protect their water resources and minimise the impacts of development on their river systems. The concept of ‘minimum flows’ was initially established as a solution but it did not provide sufficient protection as all elements of a flow regime were found to be important for the protection of the river ecosystem. “Environmental flows” were developed to determine these flow regimes to maintain a river in some defined ecological condition. Rapid, initial estimates of the quantity component of environmental flows may be determined using the Desktop Reserve Model in South Africa. However, the Desktop Reserve Model is dependent upon the characteristics of the reference natural hydrology used. The advancements in hydraulic and ecological relationships from the past decade have prompted the development of a Revised Desktop Reserve Model (RDRM) that would incorporate these relationships. The research in this thesis presents the development of the hydraulic sub-model for the RDRM. The hydraulic sub-model was designed to produce a realistic representation of the hydraulic conditions using hydraulic parameters/characteristics from readily available information for any part of South Africa. Hydraulic data from past EWR studies were used to estimate the hydraulic parameters. These estimated hydraulic parameters were used to develop hydraulic estimation relationships and these relationships were developed based on a combination of regression and rule-based procedures. The estimation relationships were incorporated into the hydraulic sub-model of the integrated RDRM and assessments of the hydraulic outputs and EWR results were undertaken to assess the ‘applicability’ of the hydraulic sub-model. The hydraulic sub-model was assessed to be at a stage where it can satisfactorily be incorporated in the RDRM and that it is adequately robust in many situations. Recommendations for future work include the refinement of estimation of the channel forming discharge or the use of spatial imagery to check the maximum channel width estimation. It is also proposed that a future version of the hydraulic sub-model could include flow regime change impacts on channel geomorphology and sedimentology so that flow management scenarios can be more effectively assessed.
8
Hadley, Jennifer Lyn. "Near real-time runoff estimation using spatially distributed radar rainfall data". Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/346.
Pełny tekst źródłaStreszczenie:
The purpose of this study was to evaluate variations of the Natural Resources Conservation Service (NRCS) curve number (CN) method for estimating near real-time runoff for naturalized flow, using high resolution radar rainfall data for watersheds in various agro-climatic regions of Texas. The CN method is an empirical method for calculating surface runoff which has been tested on various systems over a period of several years. Many of the findings of previous studies indicate the need to develop variations of this method to account for regional and seasonal changes in weather patterns and land cover that might affect runoff. This study seeks to address these issues, as well as the inherent spatial variability of rainfall, in order to develop a means of predicting runoff in near real-time for water resource management. In the past, raingauge networks have provided data for hydrologic models. However, these networks are generally unable to provide data in real-time or capture the spatial variability associated with rainfall. Radar networks, such as the Next Generation Weather Radar (NEXRAD) of the National Weather Service (NWS), which are widely available and continue to improve in quality and resolution, can accomplish these tasks. In general, a statistical comparison of the raingauge and NEXRAD data, where both were available, shows that the radar data is as representative of observed rainfall as raingauge data. In this study, watersheds of mostly homogenous land cover and naturalized flow were used as study areas. Findings indicate that the use of a dry antecedent moisture condition CN value and an initial abstraction (Ia) coefficient of 0.1 produced statistically significant results for eight out of the ten watersheds tested. The urban watershed used in this study produced more significant results with the use of the traditional 0.2 Ia coefficient. The predicted results before and during the growing season, in general, more closely agreed with the observed runoff than those after the growing season. The overall results can be further improved by altering the CN values to account for seasonal vegetation changes, conducting field verification of land cover condition, and using bias-corrected NEXRAD rainfall data.
9
Dehm, Dustin. "A Small Unmanned Aerial System (sUAS) Based Method for Monitoring Wetland Inundation & Vegetation". University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1556713788128588.
Pełny tekst źródła
10
Friedrich, Marciano. "Influência da precipitação no uso do método silveira para bacias hidrográficas entre 800 a 1000 km²". Universidade Federal de Santa Maria, 2017. http://repositorio.ufsm.br/handle/1/12185.
Pełny tekst źródłaStreszczenie:
The increasing demand for water resources, for the most diverse purposes, has evidenced a still deficient scenario in relation to fluviometric monitoring, especially in river basins with areas smaller than 1000 km², in large part of the regions of Brazil. Inevitably, these demands are linked to water availability and your determination in lack of measured data becomes necessary to resort to techniques such as regionalization of flows, or the simulation through rain-flow models. However, a period of hydrological monitoring data is still necessary to enable the application of these methodologies. In 1997 it was proposed a method that uses a few samplings of local flow measurements for the determination of the minimum flows through a rain-flow model, whose mathematical process involves two parameters, the Cinf and the Ksub. The first is related to water balance and the second to the river depletion. The objective of this work was to verify the influence of precipitation in the application of this methodology in basins between 800 and 1000 km² in order to subsidize information about the elaboration of a protocol of use of the method. For the case study, four basins with areas between 817 and 965 km² were used, with the availability of fluviometric and pluviometric data series. The methodology used was based on the Silveira method. Initially, rainfall scenarios were elaborated in the four basins for later selection of the drought events, which along with the rainfall scenarios, resulted in a total of 1407 simulations using the Silveira method. For each simulation, a flow continuity curve was generated. The determination of the errors was performed between the pairs of simulated flows and those observed for the considered percentiles. It was observed a tendency of improvement in the results of the simulations, translated by the smaller dispersion of errors, when the precipitation information from more than one pluviometric station is used. Regarding the spatial position of the pluviometric stations, it was verified that there were no significant impacts on the errors when data from the stations located at different points inside the basin and your surroundings.A crescente demanda pelos recursos hídricos, para as mais diversas finalidades, tem evidenciado um cenário ainda deficitário em relação ao monitoramento fluviométrico, sobretudo em bacias hidrográficas com áreas inferiores a 1000 km², em grande parte das regiões do Brasil. As demandas estão vinculadas a disponibilidade hídrica e para a sua determinação em locais com carência de dados medidos torna-se necessário recorrer a técnicas como a regionalização de vazões, ou a simulação por meio de modelos chuva-vazão. Em 1997 foi proposto um método que se utiliza de poucas amostragens de medições de vazões locais para a determinação das vazões mínimas por meio de um modelo chuva-vazão, cujo processo matemático envolve dois parâmetros, o Cinf e o Ksub. O primeiro está relacionado ao balanço hídrico e o segundo ao deplecionamento fluvial. O objetivo desse trabalho foi verificar a influência da precipitação na aplicação dessa metodologia em bacias entre 800 a 1000 km² visando subsidiar informações acerca da elaboração de um protocolo de uso do método. Para o estudo de caso utilizaram-se quatro bacias com áreas entre 817 e 965 km² com disponibilidade de séries de dados fluviométricos e pluviométricos. A metodologia utilizada foi baseada no método Silveira. Inicialmente foram elaborados cenários de chuvas nas quatro bacias para posterior seleção dos eventos de estiagem, que juntamente com os cenários de chuvas, resultaram em um total de 1407 simulações por meio do uso do método Silveira. Para cada simulação foi gerada uma curva de permanência das vazões. A determinação dos erros foi realizada entre os pares de vazões simulados e os observados para os percentis considerados. Observou-se uma tendência de melhora nos resultados das simulações, traduzido pela menor dispersão dos erros, quando se utiliza informações de precipitação de mais de um posto pluviométrico. Com relação à posição espacial dos postos pluviométricos, verificou-se que não houve impactos significativos nos erros quando se utilizou dados dos postos localizados em diferentes pontos no interior da bacia e no seu entorno.
11
Tuozzolo, Stephen. "A study of river discharge estimation methods for the forthcoming Surface Water and Ocean Topography (SWOT) mission". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu154150483606865.
Pełny tekst źródła
12
Eddy, Alex Michelle. "A mixed method approach to exploring and characterizing ionic chemistry in the surface waters of the glacierized upper Santa River watershed, Ancash, Peru". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1339051704.
Pełny tekst źródła
13
Wetterhall, Fredrik. "Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions". Doctoral thesis, Uppsala University, Department of Earth Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5937.
Pełny tekst źródłaStreszczenie:
A global climate change may have large impacts on water resources on regional and global scales. General circulation models (GCMs) are the most used tools to evaluate climate-change scenarios on a global scale. They are, however, insufficiently describing the effects at the local scale. This thesis evaluates different approaches of statistical downscaling of precipitation from large-scale circulation variables, both concerning the method performance and the optimum choice of predictor variables.
The analogue downscaling method (AM) was found to work well as “benchmark” method in comparison to more complicated methods. AM was implemented using principal component analysis (PCA) and Teweles-Wobus Scores (TWS). Statistical properties of daily and monthly precipitation on a catchment in south-central Sweden, as well as daily precipitation in three catchments in China were acceptably downscaled.
A regression method conditioning a weather generator (SDSM) as well as a fuzzy-rule based circulation-pattern classification method conditioning a stochastical precipitation model (MOFRBC) gave good results when applied on Swedish and Chinese catchments. Statistical downscaling with MOFRBC from GMC (HADAM3P) output improved the statistical properties as well as the intra-annual variation of precipitation.
The studies show that temporal and areal settings of the predictor are important factors concerning the success of precipitation modelling. The MOFRCB and SDSM are generally performing better than the AM, and the best choice of method is depending on the purpose of the study. MOFRBC applied on output from a GCM future scenario indicates that the large-scale circulation will not be significantly affected. Adding humidity flux as predictor indicated an increased intensity both in extreme events and daily amounts in central and northern Sweden.
14
Jaedicke, Christian. "Lake Evaporation Estimation by Isotope, Energy Balance and Bulk Aerodynamic Methods". Thesis, Uppsala universitet, Institutionen för geovetenskap, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-393212.
Pełny tekst źródłaStreszczenie:
Lake evaporation from a shallow lake in central Sweden has been estimated using three independent methods from measurements during summer 1995. The applied isotope method is a combination of the water and isotope mass balance. Its main feature is that inflows need not to be measured. Only knowledge of their isotopic content is sufficient. For calculations by the bulk aerodynamic method a computer program was applied, which takes into account the different conditions of stratification. The energy balance of the lake was determined by using the short and long wave radiation, heat storage and advective heat energy. Measurements were done on a small island and at a mast in the middle of the lake. Evaporation estimated by all the methods varied from -1.1 to 5.0 mm/d during the summer months 1995. Values estimated by the energy balance method agreed well with those from the bulk aerodynamic method. Evaporation estimates from the isotope method a showed fairly good agreement with the two other methods, excepting a few periods. It was found that both the isotope as well as the energy balance method are sensitive to errors in lake volume. Both methods carry some uncertainty due to their dependence on water balance components, some of which are difficult to determine. The bulk aerodynamic method is independent of the water balance of the lake. A good accuracy can be achieved using only four variables i.e. wind speed, relative humidity, skin and air temperature.Avdunstningen från den grunda sjön Tämnaren i centrala Sverige bestämdes med tre oberoende metoder ur mätningar från sommaren 1995. Den använda isotopmetoden är en kombination av vatten- och isotopbalansen. Dess viktigaste fördel är att inflödet inte behöver mätas, utan att kännedom om isotophalten är tillräcklig. För beräkningarna med den bulk-aerodynamiska metoden användes ett datorprogram som tar hänsyn till atmosfärens stabilitet. Energibalansen beräknades ur kort- och långvågsstrålningen, värmelagringen och den tillförda energin. Mätningarna utfördes dels på en liten ö och dels vid en mast mitt i sjön. Avdunstningen varierade mellan -1.1 mmd-1 till 5.0 mmd-1. Resultaten från energibalansmetoden överenstämde bra med resultaten från den bulk-aerodynamiska metoden. Även resultaten från isotopmetoden överenstämde bra med resultaten från de två andra metoderna, med undantag av några få perioder. Både isotop- och energibalansmetoden var känsliga för feluppskattningar av sjövolymen. Båda metoderna innehåller osäkerheter som en följd av deras beroende på vissa av vattenbalansens komponenter, som är svåra att bestämma. Den bulk-aerodynamiska metoden är oberoende av sjöns vattenbalans och en bra noggranhet kan uppnås med mätningar av endast de fyra variablerna vindhastighet, relativ fuktighet, yt- och lufttemperatur.
Die Verdunstung von einem flachen See in Zentralschweden wurde mit Hilfe von drei unabhängigen Methoden bestimmt. Die Messungen wurden im Sommer 1995 durchgeführt. Die angewandte Isotopenmethode ist eine Kombination aus Wasserbilanz and lsotop-Massenbilanz. Das besondere Merkmal dieser Methode ist es, daß Zuflüsse nicht gemessen werden müssen. Es genügt, ihre isotopische Zusammensetzung zu kennen. Für die Berechungen mit der bulk-aerodynamischen Methode wurde ein Computerprogamm verwendet, das die unterschiedlichen atmosphärischen Schichtungen berücksichtigt. Die Energiebilanz des Sees wurde mit Hilfe der kurz- und langwelligen Strahlung, der gespeicherten Energie im See und der durch Zuflüsse und Niederschlag zugeführten Energie bestimmt. Die Messungen wurden auf einer kleiner Insel und an einem Mast in der Mitte des Sees durchgeführt. Die Verdunstung reichte von -1.1 mmd-1 bis 5.0 mmd-1 während der Sommermonate 1995. Die Ergebnisse der Energiebilanz stimmten gut mit den Ergebnissen der bulk-aerodynamischen Methode überein. Die Ergebnisse der Isotopenmethode stimmten relativ gut mit den Ergebnissen der beiden anderen Methoden überein, mit Ausnahme einiger Perioden. Es wurde festgestellt, daß sowohl die Isotopenmethode als auch die Energiebilanzmethode sensibel auf Fehler im Seevolumen reagieren. Beide Methoden enthalten einige Unsicherheiten wegen ihrer Abhängikeit von Wasserbilanzkomponenten, die z.T. schwer zu bestimmen sind. Die bulk-aerodynamische Methode dagegen ist unabhängig von der Wasserbilanz des Sees. Gute Ergebnisse können mit nur vier zu messenden Variablen erreicht werden (Windgeschwindigkeit, relative Luftfeuchtigkeit, Wasseroberflächen- und Lufttemperatur).
Parts of the thesis work later published as:
Saxena, R., Jaedicke, C., & Lundin, L. C. (1999). Comparison of lake evaporation estimated by isotope mass-balance, bulk-aerodynamic and bowen ratio methods. Phys. Chem Earth (B), Vol. 24, No. 7, pp. 851–859.
and
Saxena, R., & Jaedicke, C. (1997). Estimation of vapour flux from a shallow lake by oxygen -18 mass balance. Isotope Techniques in the Study of Environmental Change, 225–237. Vienna: IAEA-SM-349/23.
15
Wealands, Stephen Russell. "Quantitative methods for hydrological spatial field comparison /". Connect to thesis, 2006. http://eprints.unimelb.edu.au/archive/00002722.
Pełny tekst źródła
16
Woodson, David. "Precipitation Estimation Methods in Continuous, Distributed Urban Hydrologic Modeling". Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90373.
Pełny tekst źródłaStreszczenie:
Quantitative precipitation estimation (QPE) remains a key area of uncertainty in hydrological modeling, particularly in small, urban watersheds which respond rapidly to precipitation and can experience significant spatial variability in rainfall fields. Few studies have compared QPE methods in small, urban watersheds, and studies which have examined this topic only compared model results on an event basis using a small number of storms. This study sought to compare the efficacy of multiple QPE methods when simulating discharge in a small, urban watershed on a continuous basis using an operational hydrologic model and QPE forcings. The Research Distributed Hydrologic Model (RDHM) was used to model a basin in Roanoke, Virginia, USA forced with QPEs from four methods: mean field bias (MFB) correction of radar data, kriging of rain gauge data, uncorrected radar data, and a basin-uniform estimate from a single gauge inside the watershed. Based on comparisons between simulated and observed discharge at the basin outlet for a 6-month period in 2018, simulations forced with the uncorrected radar QPE had the highest accuracy, as measured by root mean square error (RMSE) and peak flow relative error, despite systematic underprediction of the mean areal precipitation (MAP). Simulations forced with MFB corrected radar data consistently and significantly overpredicted discharge but had the highest accuracy in predicting the timing of peak flows.Master of Science
Estimating the amount of rain that fell during a precipitation event remains a key source of error when predicting how much stormwater runoff will be produced, particularly in small, urban watersheds which respond rapidly to precipitation and can experience significant spatial variability in rainfall distribution. Rainfall estimation in small, urban watersheds has received relatively little attention, and studies which have examined this topic have generally only examined a small number of discrete storm events. This study sought to compare the efficacy of multiple precipitation estimation methods when simulating discharge in a small, urban watershed on a continuous basis using an operational hydrologic model and precipitation inputs. The Research Distributed Hydrologic Model (RDHM), commonly used by the National Weather Service, was used to model a basin in Roanoke, Virginia, USA forced with rainfall estimates from four methods: mean field bias (MFB) correction of radar data, kriging of rain gauge data, uncorrected radar data, and a basin-uniform estimate from a single gauge inside the watershed. Based on comparisons between simulated and observed discharge at the basin outlet for a 6-month period in 2018, simulations forced with the uncorrected radar QPE had the highest accuracy, as measured by several performance statistics, despite systematic underprediction of actual precipitation. Simulations forced with MFB corrected radar data consistently and significantly overpredicted discharge but had the highest accuracy in predicting the timing of peak flows.
17
Fischer, Sandra. "Exploring a Water Balance Method on Recharge Estimations in the Kilombero Valley, Tanzania". Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-92345.
Pełny tekst źródłaStreszczenie:
Simple models that require little input data and are easy to use is the ideal case within hydrology. Basic water balance principles often represent such approaches as the method on rainfall-runoff relationship developed by Sutcliffe et al. in India in 1981. That was tested for the Kilombero Valley in Tanzania in order to estimate the recharge to the soil and sub-surface systems. Measured annual runoff in the streams was compared to the seasonal net rainfall to give the difference as potential recharge. This was done for five separate sub-catchment where the hillslope catchments gave a smaller proportion of the net rainfall to occur as surface runoff compared to the valley-catchments. Due to the difference in hydrologic setting from the original model site in India to the Kilombero Valley (e.g. a wetland and stream type), the soil moisture recharge could not be estimated. Also, corrections are needed to the data preparation process and the state of the original stream flow data is questionable. Thus, the results were interpreted as an indication on how the water resources could be moving in the system. An explaining theory that captured the difference between the landform types is mountain system recharge. That implied that all surplus rainfall generated in the mountains has a potential to eventually recharge the groundwater. The method tested, though its simple general concepts, could not alone give satisfying results for the Kilombero Valley system. However, this study convey the importance of continuous exploration of methods to describe the environment in a simplified way.
18
Williams, Evan Shane. "Hydrologic and economic impacts of alternative residential land development methods". [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0002367.
Pełny tekst źródła
19
Williams, Leslie Lavinia. "POST-EMPLACEMENT LEACHING BEHAVIORS OF NANO ZERO VALENT IRON MODIFIED WITH CARBOXYMETHYLCELLULOSE UNDER SIMULATED AQUIFER CONDITIONS". Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1389376802.
Pełny tekst źródła
20
Zhang, Xuesong. "Evaluating and developing parameter optimization and uncertainty analysis methods for a computationally intensive distributed hydrological model". [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3091.
Pełny tekst źródła
21
Wang, Ning. "Development of Improved Methods for Watershed-Scale Topographic Analysis and Hydrologic Modeling". Diss., North Dakota State University, 2020. https://hdl.handle.net/10365/31826.
Pełny tekst źródłaStreszczenie:
Surface depressions are one of the significant topographic characteristics in depression-dominated areas and can retain runoff and break the hydrologic continuity in watersheds. In traditional semi-distributed models, the entire area of a watershed is assumed to be well connected to its associated outlet and depressions are often lumped as a single depth to control runoff water release. Consequently, hydrologic processes related to depressions cannot be directly simulated. The overall goal of this dissertation research is to analyze and quantify the topographic characteristics of surface depressions and their impacts on hydrologic processes in depression-dominated areas. The specific objectives of this research are: (1) to improve watershed delineation to further reveal the topographic characteristics and hydrologic connectivity within watersheds, (2) to analyze the impact of depressions on runoff processes during rainfall events and the mechanism of water release from depressions, and (3) to analyze the functionalities of depressions in continuous simulation of hydrologic processes and connectivity. A new algorithm was developed for hydrologic unit delineation of depressions and channels (HUD-DC), in which a unique method was proposed to identify depression- and channel-associated hydrologic units and their connections. The HUD-DC delineation results highlighted the significance of depressions and the complex connectivity in depression-dominated areas. Additionally, the delineation under different filling conditions provided helpful guidance for the identification of filling thresholds to remove artifacts in digital elevation models. To achieve the second objective, a depression-oriented, event-based hydrologic model (HYDROL-D) was developed with considering separate modeling for depressional and non-depressional areas, and hierarchical control thresholds for water release from depressions. The HYDROL-D modeling results for a watershed in North Dakota revealed the intrinsic threshold behavior of surface runoff over the watershed and the effectiveness of the hierarchical control thresholds. A depression-oriented hydrologic model with accounting for dynamic hydrologic connectivity (HYDROL-DC) was further developed to continuously track runoff unit by unit. The application of HYDROL-DC in a depression-dominated watershed showed that depressions had not only retention but also acceleration capabilities in surface runoff generation. Additionally, the spatial distribution of depressions exhibited dynamic influences on hydrologic connectivity and the related threshold behavior of runoff processes.
22
Tjia, Dewi. "Statistical Methods for History Matching of Hydrological Model". Thesis, Curtin University, 2016. http://hdl.handle.net/20.500.11937/57347.
Pełny tekst źródłaStreszczenie:
Four history matching methods were used to calibrate the parameters of the LUCICAT model for three catchments in Western Australia. The methods used were ant colony optimization (ACOR and DACOR), Robust Parameter Estimation and Gauss Levenberg Marquadt. These methods were applied directly and indirectly, and in the latter case multidimensional Kriging and artificial neural networks were used to build proxy models for LUCICAT. All HM methods performed favourably well.
23
Her, Young Gu. "HYSTAR: Hydrology and Sediment Transport Simulation using Time-Area Method". Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/27503.
Pełny tekst źródłaStreszczenie:
A distributed approach can improve functionality of H/WQ (Hydrology and Water Quality) modeling by facilitating a way to explicitly incorporate spatial characteristics of a watershed into the model. The time-area approach, with its intuitive and inherently distributed concept, provides a simple method to simulate runoff mechanisms. This study developed a distributed model based on the time-area approach with the goal of improved utility and efficiency in H/WQ modeling.
Uncertainty is always introduced into watershed modeling because of imperfect knowledge and scale dependant spatial heterogeneity and temporal variability. Uncertainty analysis can provide a modeler, policy maker, and stakeholder with reliability information, better understanding, and better communication about the modeling results. This study quantified uncertainty of the model parameter and output through uncertainty analysis in order to assess risk in watershed management. The main goal of this study was to develop a hydrology and sediment transport model capable of routing overland flow using a time-area concept and providing reliability of the modeling results in a probabilistic manner through uncertainty analysis.
The HYSTAR (HYdrology and Sediment transport simulation using Time-ARea method) model incorporates a modified Curve Number (CN) method and the newly devised time-area routing method to estimate runoff. HYSTAR is capable of simulating direct runoff, base flow, soil moisture, and sediment load in a distributed manner and in an hourly time step. In the model, the modified CN and a continuity equation are used to calculate infiltration of the routed runoff as well as rainfall on every overland cell. The effective direct runoff volume is distributed over downstream areas using the newly developed routing method. A direct runoff hydrograph is constructed directly through the discrete convolution of the time-area histogram and the effective direct runoff volume
map without employing a unit hydrograph. In addition, sediment transport is simulated using the routing method and the sediment transport capacity approach without using a delivery ratio.
The sensitivity analysis found that the CN and root zone depth were the most critical parameters for runoff simulation with HYSTAR. The model provided acceptable performance in predicting runoff and sediment load of a subwatershed of the Owl Run Watershed (ORD) with the Nash-Sutcliffe efficiency coefficient and coefficient of determination greater than 0.5. However, it failed to reproduce runoff for a subwatershed of Polecat Creek Watershed (PCA), where data show that runoff is not immediately responsive to rainfall.
Uncertainty analysis revealed that the confidence intervals of the simulated monthly runoff and sediment load corresponded to 9.7 % and 10.2 % of their averages, respectively, at a significance level of 0.05. In addition, the average ranges of variation created by the Digital Elevation Model (DEM) and National Land Cover Data (NLCD) errors in the simulated monthly runoff and sediment load were equivalent to 7.5 % and 15.9 % of the average of their calibrated values, respectively. Based on the uncertainty analysis results, the Margin of Safety (MOS) of Total Maximum Daily Load (TMDL) were explicitly quantified as corresponding to 7.0 % and 21.3 % of the average of the simulated runoff and sediment load for ORD at significance level of 0.05.
In conclusion, the HYSTAR model provided a new way to explicitly simulate runoff and sediment load of a watershed in a distributed manner. The approach developed here retains the simplicity of a unit hydrograph approach without employing numerical methods. Uncertainty analysis found that parameter uncertainty had greater impact on the model output than did expected Geographic Information System (GIS) data errors. In addition, the impact of the topographic data error on the model output was greater than was that of the land cover data error. Finally, this study provided a proof that a 5 to 10 % MOS that many TMDL studies consider underestimates modeling uncertainty.Ph. D.
24
Noh, Seong Jin. "Sequential Monte Carlo methods for probabilistic forecasts and uncertainty assessment in hydrologic modeling". 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/170084.
Pełny tekst źródła
25
Hameed, Maysoun Ayad. "Evaluating Global Sensitivity Analysis Methods for Hydrologic Modeling over the Columbia River Basin". PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2398.
Pełny tekst źródłaStreszczenie:
Global Sensitivity Analysis (GSA) approach helps to identify the effectiveness of model parameters or inputs and thus provides essential information about the model performance. The effects of 14 parameters and one input (forcing data) of the Sacramento Soil Moisture Accounting (SAC-SMA) model are analyzed by using two GSA methods: Sobol' and Fourier Amplitude Sensitivity Test (FAST). The simulations are carried out over five sub-basins within the Columbia River Basin (CRB) for three different periods: one-year, four-year, and seven-year. The main parameter sensitivities (first-order) and the interactions sensitivities (second-order) are evaluated in this study. Our results show that some hydrological processes are highly affected by the simulation length. In other words, some parameters reveal importance during the short period simulation (e.g. one-year) while other parameters are effective in the long period simulations (e.g. four-year and seven-year). Moreover, the reliability of the sensitivity analysis results is compared based on 1) the agreement between the two sensitivity analysis methods (Sobol' and FAST) in terms of highlighting the same parameters or input as the most influential parameters or input and 2) how the methods are cohered in ranking these sensitive parameters under the same conditions (sub-basins and simulation length). The results show that the coherence between the Sobol' and FAST sensitivity analysis methods. Additionally, it is found that FAST method is sufficient to evaluate the main effects of the model parameters and inputs. This study confirms that the Sobol' and FAST methods are reliable GSA methods that can be applied in different scientific applications. Finally, as a future work, we suggest to study the uncertainty associated with the sensitivity analysis approach regarding the reliability of evaluating different sensitivity analysis methods.
26
Thiemann, Michael, i Michael Thiemann. "Uncertainty estimation of hydrological models using bayesian inference methods". Thesis, The University of Arizona, 1999. http://hdl.handle.net/10150/626808.
Pełny tekst źródłaStreszczenie:
Intensive investigations of hydrologic model calibration during the last two decades
have resulted in a reasonably good understanding of the issues involved in the process of
estimating the numerous parameters employed by these codes. Nevertheless, these
classical "batch" calibration approaches require substantial amounts of data to be stable,
and the subsequent model forecasts do not usually represent the various imbedded
uncertainties. Especially in the light of thousands of uncalibrated catchments in need of
model simulations for streamflow predictions, a parameter estimation approach is
required that is able to simultaneously perform model calibration and prediction without
neglecting the substantial uncertainties in the computed forecasts. This thesis introduces
the Bayesian Recursive Estimation scheme (BaRE), a method derived from Bayesian
probability computation and adapted for the use in "on-line" hydrologic model
calibration. The results of preliminary case studies are presented to illustrate the
practicality of this simple and efficient approach.
27
Voulgaridis, Theo. "Modeling hydrometeorological extremes in Alpine catchments". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-327385.
Pełny tekst źródłaStreszczenie:
Uncertainties with a modeling framework consisting of a weather generator, two precipitation disaggregation models and the hydrological HBV model was assessed with respect to hydrometeorological extremes in Tyrol, Austria. Extreme precipitation events are expected to increase in intensity and frequency in the Alps during a warmer climate. The Alpine regions may be particularly vulnerable to such changes in climate where many floods in Europe occurred during recent years and caused major damage and loss of life. Weather generators typically provide time series at daily resolution. Different disaggregation methods have therefore been proposed and successfully tested to increase temporal resolution in precipitation. This is essential since flood peaks may be maintained for as little as minutes. Here, the non-parametric method of fragments was tested and compared with the multiplicative microcanonical cascade model with uniform splitting on the reproduction of precipitation extremes. It is also demonstrated that the method of fragments model can be transformed to disaggregate temperature with slight changes in the model structure. Preliminary test results show that the simulation of discharge peaks can be improved by disaggregating temperature in comparison with using daily averages as input in the HBV model. Test results show that precipitation extremes were simulated within confidence bounds for Kelchsauer and Gurglbach when using historical observations as input. These two catchments had longer records of data available in comparison with Ruetz where the majority of simulated precipitation extremes were found outside confidence ranges. This indicates that the model is data driven. Synthetic data series were constructed with the weather generator from historical data and disaggregated with the two disaggregation models. The differences between the models were bigger for Ruetz where less observed data was available. The method of fragments simulates extremes with the closest resemblance to extremes. This is also true for the reproduction of wet spells and simulated variance. To account for parameter uncertainty in the HBV model, it is highly motivated to simulate discharge with different but suitable parameter sets to account for equifinality. However, the large amount of data produced when disaggregating the weather generated time series transcended the data capacity of the HBV model and made it crash. Other uncertainties related to the framework are the use of theoretical probability distributions in the weather generator and the dependence of high-resolution data for the disaggregation model. Despite these uncertainties, the framework is closer to a physical understanding of the causes of floods than the uncertain frequency analysis method. The framework is also applicable to land-use and climate change studies.
28
Smith, Arlynn W. "Light confinement and hydrodynamic modeling of semiconductor structures by volumetric methods". Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/13407.
Pełny tekst źródła
29
Johnston, Carey Andrew. "Development and Evaluation of Infilling Methods for Missing Hydrologic and Chemical Watershed Monitoring Data". Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/10028.
Pełny tekst źródłaStreszczenie:
Watershed monitoring programs generally do not have perfect data collection success rates due to a variety of field and laboratory factors. A major source of error in many stream-gaging records is lost or missing data caused by malfunctioning stream-side equipment. Studies estimate that between 5 and 20 percent of stream-gaging data may be marked as missing for one reason or another. Reconstructing or infilling missing data methods generate larger sets of data. These larger data sets generally generate better estimates of the sampled parameter and permit practical applications of the data in hydrologic or water quality calculations. This study utilizes data from a watershed monitoring program operating in the Northern Virginia area to: (1) identify and summarize the major reasons for the occurrence of missing data; (2) provide recommendations for reducing the occurrence of missing data; (3) describe methods for infilling missing chemical data; (4) develop and evaluate methods for infilling values to replace missing chemical data; and (5) recommend different infilling methods for various conditions. An evaluation of different infilling methods for chemical data over a variety of factors (e.g., amount of annual rainfall, whether the missing chemical parameter is strongly correlated with flow, amount of missing data) is performed using Monte Carlo modeling. Using the results of the Monte Carlo modeling, a Decision Support System (DSS) is developed for easy application of the most appropriate infilling method.Master of Science
30
Paudel, Murari. "An Examination of Distributed Hydrologic Modeling Methods as Compared with Traditional Lumped Parameter Approaches". BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2219.
Pełny tekst źródłaStreszczenie:
Empirically based lumped hydrologic models have an extensive track record of use where as physically based, multi-dimensional distributed models are evolving for various engineering applications. Despite the availability of high resolution data, better computational resources and robust numerical methods, the usage of distributed models is still limited. The purpose of this research is to establish the credibility and usability of distributed hydrologic modeling tools of the United States Army Corps of Engineers (USACE) in order to promote the extended use of distributed models. Two of the USACE models were used as the modeling tools for the study, with Gridded Surface and Subsurface Hydrologic Analysis (GSSHA) representing a distributed and with Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) representing a lumped model. Watershed Modeling System (WMS) was used as the pre- and post-processing tool. The credibility of distributed models has been established by validating that the distributed models are efficient in solving complex hydrologic problems. The distributed and lumped models in HEC-HMS were compared. Similarly, the capabilities of GSSHA and lumped models in HEC-HMS in simulating land use change scenario were compared. The results of these studies were published in peer-reviewed journals. Similarly, the usability of the distributed models was studied taking GSSHA-WMS modeling as a test case. Some of the major issues in GSSHA-modeling using WMS interface were investigated and solutions were proposed to solve such issues. Personal experience with GSSHA and feedback from the students in a graduate class (CE531) and from participants in the USACE GSSHA training course were used to identify such roadblocks. The project being partly funded by the USACE Engineering Research and Development Center (ERDC) and partly by Aquaveo LLC, the research was motivated in improving GSSHA modeling using the WMS interface.
31
Kuhnert, Matthias, Andreas Güntner, Mechthild Klann, Garrido F. Martin i Birgit Zillgens. "Methods for spatial pattern comparison in distributed hydrological modelling : [Poster]". Universität Potsdam, 2006. http://www.uni-potsdam.de/imaf/events/ge_work0602.html.
Pełny tekst źródłaStreszczenie:
The rigorous development, application and validation of distributed hydrological models obligates to evaluate data in a spatially distributed way. In particular, spatial model predictions such as the distribution of soil moisture, runoff generating areas or nutrient-contributing areas or erosion rates, are to be assessed against spatially distributed observations. Also model inputs, such as the distribution of modelling units derived by GIS and remote sensing analyses, should be evaluated against groundbased observations of landscape characteristics. So far, however, quantitative methods of spatial field comparison have rarely been used in hydrology.
In this paper, we present algorithms that allow to compare observed and simulated spatial hydrological data. The methods can be applied for binary and categorical data on regular grids. They comprise cell-by-cell algorithms, cell-neighbourhood approaches that account for fuzziness of location, and multi-scale algorithms that evaluate the similarity of spatial fields with changing resolution. All methods provide a quantitative measure of the similarity of two maps.
The comparison methods are applied in two mountainous catchments in southern Germany (Brugga, 40 km2) and Austria (Löhnersbach, 16 km2). As an example of binary hydrological data, the distribution of saturated areas is analyzed in both catchments. For categorical data, vegetation zones that are associated with different runoff generation mechanisms are analyzed in the Löhnersbach. Mapped spatial patterns are compared to simulated patterns from terrain index calculations and from satellite image analysis. It is discussed how particular features of visual similarity between the spatial fields are captured by the quantitative measures, leading to recommendations on suitable algorithms in the context of evaluating distributed hydrological models.
Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung
Workshop vom 9. - 10. Februar 2006
32
Artita, Kimberly. "Computer-based decision-support methods for hydrological ecosystem services management". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/dissertations/530.
Pełny tekst źródłaStreszczenie:
Changing climates, human population growth, and aging infrastructure threaten the availability and quality of one of life's most vital resources, water. Hydrological ecosystem services are goods and benefits derived from freshwater that include flood damage mitigation, water for agricultural and commercial use, swimmable and navigable waters, and healthy aquatic habitats. Using computer algorithms inspired by biological and ecological processes known as evolutionary algorithms and on-site stormwater management practices such structural best management practices (BMPs) and green stormwater infrastructure (GSI), this research aims to maximize hydrological ecosystem services at the watershed-scale in both agricultural and urban environments by integrating these algorithms with the watershed model Soil and Water Assessment Tool (SWAT), and the hydraulic model Storm Water Management Model (SWMM). This dissertation first develops an information theoretic approach to global sensitivity analysis for distributed models, demonstrated using SWAT, and later uses the sensitive model parameters in a multi-objective automatic calibration scheme using multi-objective particle swarm optimization (MOPSO). Multiple alternative watershed-scale BMP designs (parallel terraces, detention/infiltration ponds, field borders, and grade stabilization structures) that help minimize peak runoff and annual sediment yield were simultaneously identified using SWAT coupled with the species conserving genetic algorithm (SCGA). Finally, using recently developed economic estimates called triple bottom line (TBL) accounting, watershed-scale GSI designs are identified that reduce combined sewer overflow volumes in an urban setting while maximizing the net benefit across social, economic, and environmental categories. Overall, this dissertation research provides useful and relevant computer-based tools for water resources planners and managers interested in maximizing hydrological ecosystem services benefits.
33
Dippenaar, Matthys Alois. "Assessment of vadose zone hydrology : concepts, methods, applications and guidelines". Thesis, University of Pretoria, 2014. http://hdl.handle.net/2263/43319.
Pełny tekst źródłaStreszczenie:
Vadose
zone
hydrology
is
a
developing
science
influenced
by
earth
scientists
(soil
scientists,
pedologists,
hydrogeologists,
engineering
geologists
and
geomorphologists)
and
engineers
(geotechnical).
However,
problems
faced
are
associated
with
lack
of
agreement
between
basic
concepts,
different
approaches
and
definitions,
and
difficulty
in
communicating
findings
to
other
technical
or
non-‐technical
audiences.
The
need
for
better
cross-‐disciplinary
dialogue
and
understanding
subsequently
becomes
increasingly
important,
notably
given
the
sensitivity
of
investigation
related
to
ephemeral
wetlands,
contamination
and
water
impacting
infrastructure
development.
This
thesis
therefore
aims
to
address
basic
concepts,
accepted
methodologies
and
highly
variable
and
sensitive
case
studies
in
order
to
minimise
risk
in
the
assessment
of
the
vadose
zone.
Terminologies,
quantification,
methods
and
existing
guidelines
are
critically
appraised
and
validated
based
on
three
case
studies.
Findings
are
reported
in
order
to
improve
investigation
techniques
and
to
minimise
risk.
Final
recommendations
are
made
regarding
a
proposed
vadose
zone
assessment
protocol
to
ensure
compliance
to
a
set
of
minimum
requirements
for
vadose
zone
assessment.
It
is
hoped
that
such
a
methodology
will
be
implemented
towards
protection
of
the
natural
environment,
notably
in
urban
areas,
as
well
as
to
prevent
damage
to
infrastructure.Thesis (PhD)--University of Pretoria, 2014.
lk2014
Geology
PhD
Unrestricted
34
Einfalt, Thomas. "Recherche d'une methode optimale de prevision de pluie par radar en hydrologie urbaine". Marne-la-vallée, ENPC, 1988. http://www.theses.fr/1988ENPCA007.
Pełny tekst źródłaStreszczenie:
Cette these a pour objet le premier developpement d'une methode de prevision de pluie par radar adaptee aux objectifs de l'hydrologie urbaine. Une revue des travaux effectues sur la prevision de pluie dans les vingt dernieres annees a ete accomplie. Les algorithmes prometteurs utilises dans les etudes precedentes ont ete selectionnes et ameliores en vue des objectifs de l'application envisagee: - concentration sur les fortes pluies; temps de calcul inferieur a 60 secondes sur mini-ordinateur; controle de qualite de la prevision. De cette analyse a emerge une nouvelle methode de prevision. Une comparaison detaillee sur 94 images radar et une comparaison globale sur 1068 images ont montre la fiabilite de la methode pour la prevision hydrologique. La pluie la plus importante de ces quatre dernieres annees en region parisienne a ete etudiee particulierement. De plus, deux parametres lies seulement a la structure de l'image, peuvent servir d'indice de fiabilite, calculable a priori, de chaque prevision. Finalement, la methode a ete implantee sur les ordinateurs du service departement d'assainissement de seine-saint-denis
35
賴飛丹 i Feizhou Lai. "Stochastic and chaotic behaviour of some hydrological time series". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B31233624.
Pełny tekst źródła
36
MacNeil, Richard Eric. "Geophysical investigations and groundwater modeling of the hydrologic conditions at Masaya Caldera, Nicaragua". [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001659.
Pełny tekst źródła
37
Toorman, Alexander Frederik. "Use of inverse methods for estimating unsaturated flow parameters". Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185289.
Pełny tekst źródłaStreszczenie:
Transient laboratory experiments are evaluated for their use in inverse methods to estimate soil-water parameters for unsaturated flow. The experiments are upward infiltration, One-Step outflow, stepwise inflow and evaporation. The experiments are simulated numerically for three inch standard size cores. A theoretical sandy and a clayey soil are used and are described by the closed-form van Genuchten soil-water relations. During each numerical experiment, for each soil, measurements of different auxiliary variables are simulated. These auxiliary variables are the inflow or outflow at the boundary, and the water content and matric potential within the soil core at three different locations. For each auxiliary variable the sensitivity to estimate the parameters α, n and the saturated hydraulic conductivity is studied by plotting the objective function surface in the parameter planes defined by these parameters. The objective function is calculated for 900 points in each parameter plane and describes the error between the measured and generated auxiliary variable. The shape of these surfaces indicates how well an inverse procedure can find a unique and accurate solution. From these surfaces auxiliary variables, or combinations thereof, are selected which provide sensitive parameter estimates. The surfaces indicate that the contours are nonconvex and that confidence regions for parameters are not symmetric. The hydraulic conductivity is the least sensitive parameter to estimate. For a wetting experiment the parameter sensitivity will increase when the measurement of the auxiliary variable is taken further away from the inflow boundary. To obtain sensitive parameter estimates the auxiliary variable used in the inverse procedure needs to be least similar to the known and changed boundary variable. The shape of the objective function surface for the degenerate case, where an auxiliary variable would be measured at the changed boundary, can provide prior information regarding the sensitivity of estimating parameters from an auxiliary variable and regarding the start values of the parameters for the parameter search. The difference in parameter sensitivity between the sandy and clayey soil is small.
38
Pradhan, Nawa Raj. "Development of a topographic disaggregation method for transferring hydrological models across scales and regions". 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144538.
Pełny tekst źródła
39
Larsson, Jesper. "A historical analysis of hydrological drought in Sweden". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328133.
Pełny tekst źródłaStreszczenie:
I Sverige finns det en brist på studier angående hydrologisk torka trots att det existerar problem med torka idag. Hydrologisk torka kan ha allvarliga konsekvenser på både naturen och samhället när det kommer till vattentillgång, växt -och djurliv och jordbruk. Av den anledningen är det viktigt att studier görs som undersöker allvarligheten i den hydrologiska torkan i Sverige för att få en bättre förståelse. I den här studien användes ett månadsvis Q95 värde som ett tröskelvärde med ett minimum av fem dagar i följd under tröskelvärdet för att definiera hydrologisk torka. Metoden applicerades på fem avrinningsområden in Sverige med data som sträckte sig mellan 1961- 2010. Resultatet från studien visade på att hydrologisk torka var speciellt framträdande under v issa år. Dessa år verkade vara kopplade till varandra under två till tre år i följd. De visade även ofta liknande månader och antal dagar under tröskelvärdet. Andra studier gjorda över de Nordiska länderna visade på liknande resultat. Metoden överensstämde även till en stor del av historisk torka i Sverige. För att kunna ge en större och komplett bild av hydrologisk torka diskuterades några möjliga metoder. Nederbörd, snö, strömflöde, evapotranspiration och grundvatten skulle behöva räknas med för en mer pr ecis studie. Standardiserade index kan täcka de mesta av de olika delarna, men för att få mera specifika förlustvärden så skulle även en tröskelnivå metod behöva implementeras i studienIn Sweden there is a lack of studies on the topic of hydrological drought even though it exist present problems of drought. Hydrological drought can have severe effects on both nature and society regarding water supply, animal life and agriculture. It is important to investigate the severity of hydrological drought in Sweden to get a better understanding of this phenomenon and its affects. To define hydrological drought this study used a Q95 monthly threshold with a minimum of 5 consecutive days below the threshold. This method was used on five catchments in Sweden with data ranging from 1961 -2010. The result from the study showed that hydrological drought was very prominent in some year s. These years seemed to be often linked together in two to three consecutive years. They often had similar amount of days and months below the threshold. Other studies over the Nordic countries showed similar results. The method also gave a result that to a certain degree showed droughts that coincided with historical records of drought in Sweden. This gave a positive feedback of the index accuracy. To get a broader picture of how hydrological drought propagates in Sweden some possible choices were discuss ed. Precipitation, snow, streamflow, evapotranspiration and groundwater would need to be covered for a more precise study. Standardized indices have most of spectrum covered, but it would be suggested to implement the threshold level method as well to get accurate deficits.
40
Hawkins, Richard H., i Ali Vali Khojeini. "Initial Abstraction and Loss in the Curve Number Method". Arizona-Nevada Academy of Science, 2000. http://hdl.handle.net/10150/296552.
Pełny tekst źródła
41
Samper, Calvete F. Javier(Francisco Javier) 1958. "Statistical methods of analyzing hydrochemical, isotopic, and hydrological data from regional aquifers". Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/191115.
Pełny tekst źródłaStreszczenie:
This dissertation is concerned with the development of mathematical aquifer models that combine hydrological, hydrochemical and isotopic data. One prerequisite for the construction of such models is that prior information about the variables and parameters be quantified in space and time by appropriate statistical methods. Various techniques using multivariate statistical data analyses and geostatistical methods are examined in this context. The available geostatistical methods are extended to deal with the problem at hand. In particular, a three-dimensional interactive geostatistical package has been developed for the estimation of intrinsic and nonintrinsic variables. This package is especially designed for groundwater applications and incorporates a maximum likelihood cross-validation method for estimating the parameters of the covariance function. Unique features of this maximum likelihood cross-validation method include: the use of an adjoint state method to compute the gradient of the likelihood function, the computation of the covariance of the parameter estimates and the use of identification criteria for the selection of a covariance model. In addition, it can be applied to data containing measurement errors, data regularized over variable lengths, and to nonintrinsic variables. The above methods of analysis are applied to synthetic data as well as hydrochemical and isotopic data from the Tucson aquifer in Arizona and the Madrid Basin in Spain. The dissertation also includes a discussion of the processes affecting the transport of dissolved constituents in groundwater, the mathematical formulation of the inverse solute transport problem and a proposed numerical method for its solution.
42
Nik, Abdul Rahim H. "The effects of selective logging methods on hydrological parameters in Peninsular Malaysia". Thesis, Bangor University, 1990. https://research.bangor.ac.uk/portal/en/theses/the-effects-of-selective-logging-methods-on-hydrological-parameters-in-peninsular-malaysia(9ed5e3d1-33ab-4cb1-91b0-7c043891921f).html.
Pełny tekst źródłaStreszczenie:
An experimental forest watershed, consisting of three small catchments at Berembun, Negeri Sembilan, in Peninsular Malaysia has been monitored from 1979 to 1987. Adequate instruments were installed for continuous collection of hydrologic and climatic data. The calibration and post-treatment phases lasted for three and four years respectively. Two types of treatments were imposed -namely commercial selective logging and supervised selective logging in catchment 1 and catchment 3 whilst catchment 2 remained as a control. Pertinent logging guidelines were prescribed and assessed in C3 in terms of hydrological responses. Significant water yield increases were observed after forest treatment in both catchments amounting to 165 mm (70%) and 87 mm (37%) respectively in the first year; increases persisted to the fourth year after treatment. Magnitude and rate of water yield increase primarily depended on the amount of forest removed and the prevailing rainfall regime and the increase was largely associated with baseflow augmentation. Interestingly, both types of selective loggings produced no significant effect on peak discharge while the commercial logging resulted in a significant increase in stormflow volume and initial discharge. Such responses can be explained by the extensive nature of selective logging which normally left a substantial area of forest intact and minimal disturbance to flow channels. Thus, conservation measures introduced in this study - the use of buffer strips, cross drains, an appropriate percentage for the forest road network,- were found to be effective and beneficial in ameliorating the hydrological impacts.
43
Madadgar, Shahrbanou. "Towards Improving Drought Forecasts Across Different Spatial and Temporal Scales". PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1516.
Pełny tekst źródłaStreszczenie:
Recent water scarcities across the southwestern U.S. with severe effects on the living environment inspire the development of new methodologies to achieve reliable drought forecasting in seasonal scale. Reliable forecast of hydrologic variables, in general, is a preliminary requirement for appropriate planning of water resources and developing effective allocation policies. This study aims at developing new techniques with specific probabilistic features to improve the reliability of hydrologic forecasts, particularly the drought forecasts. The drought status in the future is determined by certain hydrologic variables that are basically estimated by the hydrologic models with rather simple to complex structures. Since the predictions of hydrologic models are prone to different sources of uncertainties, there have been several techniques examined during past several years which generally attempt to combine the predictions of single (multiple) hydrologic models to generate an ensemble of hydrologic forecasts addressing the inherent uncertainties. However, the imperfect structure of hydrologic models usually lead to systematic bias of hydrologic predictions that further appears in the forecast ensembles. This study proposes a post-processing method that is applied to the raw forecast of hydrologic variables and can develop the entire distribution of forecast around the initial single-value prediction. To establish the probability density function (PDF) of the forecast, a group of multivariate distribution functions, the so-called copula functions, are incorporated in the post-processing procedure. The performance of the new post-processing technique is tested on 2500 hypothetical case studies and the streamflow forecast of Sprague River Basin in southern Oregon. Verified by some deterministic and probabilistic verification measures, the method of Quantile Mapping as a traditional post-processing technique cannot generate the qualified forecasts as comparing with the copula-based method.
The post-processing technique is then expanded to exclusively study the drought forecasts across the different spatial and temporal scales. In the proposed drought forecasting model, the drought status in the future is evaluated based on the drought status of the past seasons while the correlations between the drought variables of consecutive seasons are preserved by copula functions. The main benefit of the new forecast model is its probabilistic features in analyzing future droughts. It develops conditional probability of drought status in the forecast season and generates the PDF and cumulative distribution function (CDF) of future droughts given the past status. The conditional PDF can return the highest probable drought in the future along with an assessment of the uncertainty around that value. Using the conditional CDF for forecast season, the model can generate the maps of drought status across the basin with particular chance of occurrence in the future. In a different analysis of the conditional CDF developed for the forecast season, the chance of a particular drought in the forecast period can be approximated given the drought status of earlier seasons.
The forecast methodology developed in this study shows promising results in hydrologic forecasts and its particular probabilistic features are inspiring for future studies.
44
Remmen, Krystle D. "A REACTIVE TRACER METHOD FOR THE MEASUREMENT OF SPECIFIC SURFACE AREA IN EGS RESERVOIRS". Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1527408.
Pełny tekst źródłaStreszczenie:
Early thermal breakthrough is an issue of concern in the geothermal industry, especially with regard to engineered geothermal systems (EGS). Determination of the specific surface area (SSA) of the fluid/rock interface in an EGS is vital to predicting early thermal breakthrough. An approach to this problem involving the application of tracers with different sorption properties (lithium, bromide, and deuterium) is presented. Upon injection into a reservoir, these tracers react along the fluid/rock interface to varying degrees. The resulting breakthrough separation at the extraction well can be used to derive SSA by applying a modified form of the advection-dispersion equation. For proof of concept, field tests were conducted in a sandstone bedding-plane fracture near Chazy, New York. Results showed minimal breakthrough separation, indicating insufficient sweep of the fracture area, and that lithium was not an ideal tracer in this medium. However, a relative measure of SSA can still be derived.
45
Armour, Arthur David 1964. "Adaptive random search evaluated as a method for calibration of the SMA-NWSFS model". Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/278394.
Pełny tekst źródłaStreszczenie:
Random search methods are becoming more widely used to estimate model parameters. Their ability to globally search a parameter space makes them attractive for solving problems that have multi-local optima, as are non-linear hydrologic models such as Conceptual Rainfall-Runoff (CRR) models. The investigation of this thesis is on the ability of the Adaptive Random Search (ARS) to find the global optimum of the CRR model known as the Soil Moisture Accounting Model of the National Weather Service River Forecast System (SMA-NWSRFS) and compares its performance to that of the Uniform Random Search (URS). Research results indicate that, although the ARS was slightly more efficient than the URS, neither strategy demonstrated an ability to converge to the globally optimum parameter set. Factors which inhibit the convergence include model structure characteristics and an insufficient number of points searched. Ways for random search techniques to identify and address these problems are discussed.
46
Cabral, Jaime Joaquim da Silva Pereira. "Boundary element method using B-splines with applications to groundwater flow". Thesis, University of Portsmouth, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304483.
Pełny tekst źródła
47
Bastidas, Luis Alberto 1950. "Parameter estimation for hydrometeorological models using multi-criteria methods". Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282748.
Pełny tekst źródłaStreszczenie:
There are three components of error in the ability of land-atmosphere models (e.g., BATS, SiB, etc.) to simulate/predict observed land-surface state variables and output fluxes (e.g. lambdaE, H, Tg, Q, etc.). The first is caused by model structural error associated with simplifications and/or inadequacies in the functional representations of underlying physical processes. The second component is measurement error associated with the input and output data. The third is caused by error in specification of the values of the model parameters. Automatic parameter tuning (model calibration) methods allow minimizing of the parameter error, thereby obtaining an estimate of the remaining error components. This work describes an automatic multi-criteria approach and its use to tune all 27 parameters of the BATS model using data measured in the field. The parameters were adjusted to simultaneously optimize the ability of the model to reproduce observed values of several output fluxes and/or state variables (e.g., latent heat flux, sensible heat flux, ground temperature, etc.). The results indicate that not only does the procedure result in conceptually reasonable and consistent parameter estimates, but the calibrated model is able to provide significant improvement in performance (33% or more reduction in error) over the "un-calibrated" model (i.e., using the BATS default parameter values for the associated region). Substantial improvements of this kind can have important implications for studies that seek to evaluate alternative model structures or to regionalize parameters. To reduce the dimensionality of the optimization problem a multi-criteria extension of the Regionalized Sensitivity Analysis (RSA) has been developed.
48
Ma, Miaomiao [Verfasser]. "Correlation Dimension analysis of complex hydrological systems : what information can the method provide? / Miaomiao Ma". Berlin : Freie Universität Berlin, 2013. http://d-nb.info/103687284X/34.
Pełny tekst źródła
49
MOUSAVI, NADOSHANI SEYED SAEID. "Composition des lois élémentaires en hydrologie régionale : application à l'étude des régimes de crue". Grenoble 1, 1997. http://www.theses.fr/1997GRE10165.
Pełny tekst źródłaStreszczenie:
Un evenement hydrologique est souvent defini d'apres plusieurs variables aleatoires presentant un certain degre de liaison. L'etude probabiliste de cet evenement necessite alors la composition de lois de probabilite. Nous avons considere deux cas d'applications : 1) l'extrapolation de la distribution du debit de pointe et du debit seuil ; 2) l'estimation du quantile du debit de crue a l'aval d'une confluence. Nous avons teste plusieurs fonctions de deux variables : les modeles de farlie-gumbel-morgenstern, de farlie et hashino, en utilisant des echantillons sup-seuil. Pour ce dernier modele, nous utilisons le coefficient de correlation obtenu avec la totalite de l'information (evenements concomitants et non concomitants). Les performances des modeles de composition ont ete testees sur des donnees reelles, puis sur des donnees simulees a l'aide du modele de generation de pluies journalieres shypre, du modele pluie-debit gr4j et d'un modele de liaison spatiale des pluies. Nous avons enfin etudie les hydrogrammes d'apport a injecter dans un modele hydraulique, de facon a rester homogene en frequence sur tout le lineaire de la riviere.
50
Zhang, Jian-Bo. "Turbulence measurements in shallow shear flow using video imaging method". Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34487.
Pełny tekst źródłaStreszczenie:
Quasi-two-dimensional turbulent flows were produced in a tank of small thickness to study confinement and friction effects on large-scale turbulent motion of small depth. The tank was constructed of two parallel walls. The space between the walls (4.4 cm, 1.57 cm and 0.59 cm) was small compared with the height (108 cm) and the width (210 cm) of the tank, and was varied during the experiments for different confinement and friction effects. Two series of experiments were conducted. In the first series turbulent flows were produced by the injection of water in the form of shallow jets into the tank filled with water of the same density. In the second series turbulent flows in the form of shallow plumes were produced by releasing saline solution from a line source, located at the top of the tank, into the tank filled with water. Dye was injected with the source fluid as the tracer. The concentration of the dye in the shallow turbulent flows was determined using a video imaging technique. From the initiation of the turbulent motion at the source to the final interaction of the jets and the plumes with the tank, the entire sequence of events was recorded by a video camera. The unsteady turbulent motions were analyzed using the recorded video images. The large-scale turbulent flow in the small space between the walls of the tank is confined to essentially two-dimensional motion, and the motion is retarded by the force of friction. The confinement effect was evaluated from the data of the shallow plume experiments, as the friction effect is neglible compared with the buoyancy effect in the case of the plume. Friction, however, is significant in the case of the jet. The effect of the friction, evaluated from the data of the shallow jet experiments, was found to have a profound effect on the entrainment processes. These findings are useful for turbulent modelling of the shallow shear flow and on its application to the large scale heat and mass exchange processes in the atm