Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 80 for “"hydrographs"”.
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Determining overland flow hydrographs from sections of nonuniform width
Dimensionless hydrographs and equations for the time of equilibrium were developed for sections of nonuniform width. In order to determine the dimensionless hydrographs the equations of momentum and continuity were solved implicitly. This method was chosen because it is unconditionally stable …
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The effect of rainstorm movement on urban drainage network runoff hydrographs
… relation between rainstorm movement and runoff hydrographs based on network configuration. This study utilizes a conceptual model based on characteristic timescales to investigate the effects of storm movement on the flood peak flows, and the underlying process controls. A broad theoretical …
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A finite element model to determine the effect of land-use changes on flood hydrographs
The finite element theory, in conjunction with Galerkin's residual method, was used to mathematically route overland and channel flow. This numerical procedure was applied to the kinematic equations of one-dimensional transient flow in open channels. A one-dimensional finite element scheme was used …
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The Effect Of Tidal Inlets On Open Coast Storm Surge Hydrographs: A Case Study Of Hurricane Ivan (2004)
… of Transportation requires design storm tide hydrographs for coastal waters surrounding tidal inlets along the coast of Florida. These hydrographs are used as open ocean boundary conditions for local bridge scour models. At present, very little information is available on the effect that tidal …
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ANALYSES OF INFLUENTIAL FACTORS FOR ACCURATE DETERMINATION OF PEAK RATE FACTORS AND TIMES TO PEAK OF UNIT HYDROGRAPHS
… the most widely used models for computing runoff hydrographs. The two-parameter gamma UH can be fully characterized by two parameters: the peak rate factor (PRF) and the time to peak (tpUH). Currently, obtaining accurate estimates of UH parameters is still a problem, especially for ungauged …
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Effect of Spatial Scale on Hydrologic Modeling in a Headwater Catchment
… with a different number of subareas in each. The hydrographs generated by each HEC-1 model for a number of large rainfall events were analyzed visually and statistically. No observable improvement resulted from increasing the number of subareas in the HEC-1 models from 20 to 81. TOPMODEL was …
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Simulation and design of diversion and detention system for urban stormwater management
… application in personal computers. Hydrographs and pollutographs are generated at the inlet and outlet of the diversion box and the detention basin.These hydrographs and pollutographs are examined and the peak outflow and peak pollutant concentrations are compared with allowable …
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Development and Evaluation of a Gis-Based Spatially Distributed Unit Hydrograph Model
Synthetic unit hydrographs, which assume uniform rainfall excess distribution and static watershed conditions, are frequently used to estimate hydrograph characteristics when observed data are unavailable. The objective of this research was to develop a spatially distributed unit hydrograph (SDUH) …
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Rainfall Organization and Geomorphologic Controls on the Flood Response of Mild-slope Basins in the South Atlantic Region of US
… model. Comparison of observed to simulated hydrographs from the hydrological model shows that distributed rainfall forcing gives improved performance evaluation metrics relative to basin-average rainfall forcing data. We employ the concepts of “Spatial Moments of Catchment Rainfall (defined …
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The application of implicit method to open-channel surges
… end of the channel. Three types of inflow hydrographs were chosen and the outflow hydrographs were obtained for different values of θ. For that type of inflow hydrograph that caused a surge to occur in the channel, it was found that θ = 0.6 gave the most satisfactory results. Experimental …
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Applications of GIS in hydrologic modeling
… technology was constructed to simulate stormflow hydrographs from a watershed. The model consists of three components: stormflow generation, translation and detention. Two major aspects were emphasised in the model: one is taking advantage of standard GIS to extract, overlay and delineate land and …
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Hydraulic Modeling of a River Network for Predicting Flood Inundation using HEC-RAS and GIS Models - A Case Study in Southern Virginia
… goal of the study was to transform discharge hydrographs produced by HEC-HMS, an event-based hydrologic model, into water surface elevations and flood inundation spatial extents. Initially, a river terrain model was constructed using data from publicly available sources and filed survey …
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Hydrologic Modeling of a Probable Maximum Precipitation Event Using HEC-HMS and GIS Models - A Case Study of Two Watersheds in Southern Virginia-
… of these simulations was to obtain discharge hydrographs associated with the Probable Maximum Flood (PMF) at key locations in each of the watersheds. These hydrographs were subsequently used to develop flood inundation maps of the study areas and to characterize sediment transport phenomena in …
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Floodplain Resource Management: An Economic Analysis of *Policy Issues in Bangladesh
… type. These are derived from simulated annual hydrographs and the area-elevation relationship estimated for the study area. We developed a statistical methodology for simulating hydrographs based on Fourier analysis. The FMM is numerically solved using data from the Bangshi-Dhaleswari …
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Evaluation of the effectiveness of BMP's for urban stormwater management: single-event simulation
… the SCS TR - 55 method for calculating runoff hydrographs for a single storm event. A methodology has been adapted to generate pollutographs which combines the SCS Type II rainfall distribution with the standard pollutant washoff equations. In addition, this model allows for the design, …
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An Evaluation of a Hydrological Model Used to Predict the Impact of Flow Attenuation on Downstream Flood Flows
… by affecting the timing and synchronicity of hydrographs from different tributaries. This demonstrated the importance of the specific geographic location of interventions. The results were compared with a hydraulic model, HEC-RAS, which is a standard tool for flood hazard prediction in the UK. …
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Bacterial and Sediment Transport in an Artificial Sand Bed Stream During Unsteady Flow
… experiments were run with field-induced storm hydrographs to determine resuspension rates of coliforms and their association with the movement of bed material. Six artificial storm events were created by varying discharge in a 0.63-m wide stainless steel flume with 2.5 m of the 8-m-long channel …
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The performance of an underground storage structure for urban stormwater quality management
… it possible to describe the inflow and outflow hydrographs. The automatic sampling equipment collected equal volume - variable time composite samples of runoff, making it possible to determine the inflow and outflow event mean concentrations of various pollutant constituents. Twenty runoff …
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Transient Seepage Analysis for Levees and Dams: Numerical and Monitoring Approaches
… conditions. An investigation into flood hydrographs collected from across the United States showed that flood durations could be hundreds of days long. These hydrographs were collected over a period of 10 years. It was found that the recorded peak flood stage exceeded the major flood …
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