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 40 for “"Curve Number"”.
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Tile -Drained Watershed Scs-Curve Number Model
… and potential maximum retention was redefined. Curve number was obtained from observed rainfall and tile flow by assuming that initial abstractions were a portion of potential maximum retention. The curve number was sensitive to the ratio of initial abstractions/potential maximum retention. …
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NRCS Curve Number Calibration Using USGS Regression Equations
The Curve Number (CN) method of estimating the direct runoff response to rainfall events was originally developed in the 1950's primarily for agricultural purposes in the mid-western United States. The accuracy of the CN method is greatly affected by variation of the soil type and land use of the …
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Green-Ampt infiltration model parameter determination using SCS curve number (CN) and soil texture class, and application to the SCS runoff model
… of Agriculture (USDA) Soil Conservation Service Curve Number (SCS CN) method is a simple and widely popular technique of estimation of direct runoff volume for design and natural rainfall events in small watersheds. The SCS CN procedure is incorporated into such computer programs as TR-20 and …
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Uganda Manafwa River early flood warning system development hydrologic watershed modeling using HEC-HMS, HEC-RAS, ArcGIS
… is on the loss methods used in HEC-HMS: the Curve Number loss method and the Initial and Constant loss method It is found out that the neither the Curve Number nor Initial and Constant loss method is perfectly suitable to modeling both short-term and long term simulations. The Curve Number …
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A quantitative analysis of the impact of land use changes on floods in the Manafwa River Basin
… due partly to climate change which enhances the number of weather extremes like excessive rainfalls or droughts. This increase in flood events is also a response to land use changes; as more people use the land for agriculture and housing the percentage of less pervious and impervious area …
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Developing and Evaluating the Composite Runoff Index Geographic Model for Urban Rainfall-Runoff Modeling
… single-parameter rainfall-runoff techniques: the curve number (CN) for the Natural Resources Conservation Service Curve-Number (NRCS-CN) method and the runoff coefficient (C) for the rational method. The RIc geographic model, as developed using Sioux Falls, South Dakota, and demonstrated in Las …
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Incorporating Spatial and Temporal Variation of Watershed Response in a GIS-based Hydrologic Model
… outlet was simulated using the time-area curve concept implemented in a geographic information system (GIS). The goal of this study was to determine if hydrograph prediction accuracy would be improved by accounting for spatial and temporal variation of excess rainfall. Three models with …
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Urban hydrological modeling of the Malden River using the Storm Water Management Model (SWMM)
… of the land surface in the study site. Both the Curve Number and Green-Ampt infiltration methods were used for the runoff processes, with the Curve Number methods producing higher runoff values. For the hydraulic processes used to calculate flow in the drainage system, kinematic wave routing was …
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Analysis and Comparison of a Detailed Land Cover Dataset versus the National Land Cover Dataset (NLCD) in Blacksburg, Virginia
… an application scenario assigns an area-weighted curve number to watersheds based on each land cover dataset. This study exhibits the importance of obtaining detailed land cover datasets for cities and towns. Furthermore, it shows the comprehensive information and subsequent quantifications that …
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Simulation of local watershed nutrient and sediment delivery to Lake Texoma.
… was predicted using a modification of the curve number method in HEC Hydrologic Modeling System (HEC-HMS). Event mean concentrations were applied to land use to estimate loadings of nutrients and TSS. Total discharge from the local watersheds was estimated to be 3.02 x 107 cubic meters for …
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Mark Scott Wetland Impoundment Near Polson, MT: Design Proposal
… </p><p>•The area has a soil conservation runoff curve number of 71 </p><p>•The time of concentration was found to be two hours </p><p>•The overflow elevation of that wetland is at 2998 feet above sea level </p><p>•The impoundment will be approximately nine acres and have a drainage basin area of …
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Using Bioretention Retrofits to Achieve the Goals of Virginia's New Stormwater Management Regulations
… Natural Resources Conservation Service (NRCS) curve number. However, the required size for some of the cells is much larger than those typically seen. With the RRM applied for all of the sub-watersheds, the resulting hydrograph at the watershed outlet has a lower peak than the pre-development …
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Parameter uncertainty in nonpoint source pollution modeling
… A conceptual approach was used to derive runoff curve number distributions suitable for use in continuous models which adjust the input curve number based on continuous moisture accounting. New regression equations were developed for predicting saturated conductivity, field capacity, and wilting …
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A comparison of Scs runoff prediction methods for two large watersheds in Sri Lanka
… on the Soil Conservation Service (SCS) runoff curve method. The study results showed that the application of standard SCS tables and standard abstractions does not adequately predict computed direct runoff. The standard SCS curve number method produced good predictions at optimum initial …
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Hydrologic Evaluation of Low Impact Development Using a Continuous, Spatially-Distributed Model
… based on maintaining the predevelopment Curve Number and time of concentration, precluding consideration of the spatial distribution of impervious areas and Integrated Management Practices (IMP's), runoff-runon processes, and the effects of land grading. Success is thus dependent on the …
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Evaluation of a Water Budget Model for Created Wetland Design and Comparative Natural Wetland Hydroperiods
… sensitivity analyses indicated that watershed curve number and outlet height had the most leverage on model output. Addition of maximum depth of water level drawdown greatly improved model accuracy. I used Nash-Sutcliffe efficiency (NSE) and root mean squared error (RMSE) to evaluate goodness …
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Hydrological Analysis of an Urban Basin in Sub-Tropical Environment
… the sub-basins and the Soil Conservation Service Curve Number (SCS-CN) map of the basin. The SCS-CN hydrograph method is used in HEC-HMS model to simulate infiltration losses and the watershed response to the different storm cases. The simulations are conducted using antecedent moisture condition …
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WATER QUALITY IMPACT OF NON-POINT SOURCE CONTAMINANTS IN SMALL TIDAL RIVERS
… source loading is based on the runoff curve number technique combined with a partial contributing area approach. Sediment washoff is used as an indicator of contaminant quantities.</p><p>Hydrographs and contaminant load time series are introduced into a set of one-dimensional estuary …
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Modeling Flash Floods in Small Ungaged Watersheds using Embedded GIS
… applies the Soil Conservation Service (SCS) curve number (CN) method and synthetic dimensionless unit hydrograph (UH), and Muskingum stream routing modeling technique to formulate flood characteristics and rapid update FFG for the study area of interest. The end result of this study is a …
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Nitrogen modeling of potato fields in the Bolivian Andes using GLEAMS
… plot repetitions using a calibrated SCS curve number of 90. The RSR and PBIAS, respectively, for soil total Kjeldahl N concentration were 3.0 and -2.2%. The RSR and PBIAS, respectively, for crop dry matter production were 7 and 21%. The RSR and PBIAS, respectively, for crop N uptake were …
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