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The Global ETD Search service is a free service for researchers
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Showing 1 to 5 of 5 (0.051 seconds)Spelling suggestions: "subject:"rainfall every""
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Hydrologic response to spring snowmelt and extreme rainfall events of different landscape elements within a prairie wetland basinLungal, Murray 29 June 2009
Depressions in the prairie pothole region (PPR) are commonly referred to as sloughs and were formed during the most recent glacial retreat, ~10-17 kyrs ago. They are hydrologically isolated, as they are not permanently connected by surface inflow or outflow channels. Extreme thunderstorms are common across the prairies and the hydrologic response of isolated wetlands to intense rainfall events is poorly understood.
The purpose of this study was to compare the response of different landscape/ecological elements of a prairie wetland to snowmelt and extreme rainstorms. Comparisons were completed by investigating the spring snowmelts of 2005 and 2006 and the rainstorm event of June 17 - 18, 2005, in which 103 mm fell at the St. Denis National Wildlife Area (NWA) Saskatchewan, Canada (106°06'W, 52°02'N). The wetland was separated into five landscape positions, the pond center (PC), grassed edge (GE), tree ring (TR), convex upland (CXU), and concave upland (CVU).
Comparison of the rainfall of June 17 18, 2005 with the spring snowmelts of 2005 and 2006 indicates that the hydrologic consequences of these different events are similar. Overland flow, substantial ponding in lowlands, and recharge of the groundwater occur in both cases. Analysis of this intense rainfall has provided evidence that common, intense rainstorms are hydrologically equivalent to the annual spring snowmelt, the major source of water for closed catchments in the PPR.
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Hydrologic response to spring snowmelt and extreme rainfall events of different landscape elements within a prairie wetland basinLungal, Murray 29 June 2009 (has links)
Depressions in the prairie pothole region (PPR) are commonly referred to as sloughs and were formed during the most recent glacial retreat, ~10-17 kyrs ago. They are hydrologically isolated, as they are not permanently connected by surface inflow or outflow channels. Extreme thunderstorms are common across the prairies and the hydrologic response of isolated wetlands to intense rainfall events is poorly understood.
The purpose of this study was to compare the response of different landscape/ecological elements of a prairie wetland to snowmelt and extreme rainstorms. Comparisons were completed by investigating the spring snowmelts of 2005 and 2006 and the rainstorm event of June 17 - 18, 2005, in which 103 mm fell at the St. Denis National Wildlife Area (NWA) Saskatchewan, Canada (106°06'W, 52°02'N). The wetland was separated into five landscape positions, the pond center (PC), grassed edge (GE), tree ring (TR), convex upland (CXU), and concave upland (CVU).
Comparison of the rainfall of June 17 18, 2005 with the spring snowmelts of 2005 and 2006 indicates that the hydrologic consequences of these different events are similar. Overland flow, substantial ponding in lowlands, and recharge of the groundwater occur in both cases. Analysis of this intense rainfall has provided evidence that common, intense rainstorms are hydrologically equivalent to the annual spring snowmelt, the major source of water for closed catchments in the PPR.
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THREE DIMENSIONAL FINITE ELEMENT MODELING OF PAVEMENT SUBSURFACE DRAINAGE SYSTEMSLiu, Yinhui 01 January 2005 (has links)
Pavement subsurface drainage systems (PSDS) are designed to drain the entrapped water out of pavement. To investigate the effects of various factors on the performance of PSDS, three dimensional models were developed using the finite element method to simulate the unsaturated drainage process in pavement. The finite element models were calibrated using the field information on outflow, peak flow, layer saturations, and time to drain. Through a series of parametric analyses, the factors that significantly influence the performance of PSDS were screened out, and a set of recommendations were made to improve our current drainage practices.The effects of pavement geometry on drainage were studied in this research. The analysis results indicate that edgedrain system can significantly improve the drainage efficiency of a pavement. The drainage performance of a pavement is mainly affected by the geometric factors that related to the edgedrain itself and the geometric factors related to the driving lanes have very limited effects.To investigate the influences of the properties of various pavement materials, some physical-empirical equations were developed in this research. These equations were used to predict the material hydraulic properties from their grain-size distributions and aggregate/asphalt contents. The analysis results of the models with various material properties indicate that the use of permeable base is effective in improving the drainage ability of a pavement. The performance of PSDS is not only affected by material permeability but also by their waterretention ability. The pavement works as an integrated hydraulic system and the hydraulic compatibility of materials must be considered in the PSDS design.The effects of climatic factors on pavement drainage were also studied in this research. A method was developed in this research to numerically describe the rainfall events. The analysis results of the models under various rainfall events indicate that rainfall duration is a more important parameter than the rainfall quantity in influencing the pavement drainage. Based on the analysis results, regression equations were developed for the estimation of pavement drainage. Finally, for design application purpose, a series of tables were included in this report to help with proper selected of pavement drainage options.
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An Urban Rainfall Storm Flood Severity IndexJobin, Erik 08 May 2013 (has links)
Extreme rainfall statistics are important for the design and management of the water resource infrastructure. The standard approach for extreme rainfall event severity assessment is the Intensity-Duration-Frequency (IDF) method. However, this approach does not consider the spatial context of rainfall and consequently does not properly describe rainfall storm severity, nor rarity. This study provides a critical account of the current standard practice and presents an approach that takes into consideration both the spatial context of rainfall storms, and indirectly incorporates runoff to produce a representative approach to assessing urban rainfall storm severity in terms of flood potential. A stepwise regression analysis was performed on a dataset of individual rainfall storm characteristics to best represent documented basement floodings in the City of Edmonton. Finally, the urban rainfall storm flood severity index was shown to be most representative of the documented basement floodings' severity when compared to that of the IDF method.
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An Urban Rainfall Storm Flood Severity IndexJobin, Erik January 2013 (has links)
Extreme rainfall statistics are important for the design and management of the water resource infrastructure. The standard approach for extreme rainfall event severity assessment is the Intensity-Duration-Frequency (IDF) method. However, this approach does not consider the spatial context of rainfall and consequently does not properly describe rainfall storm severity, nor rarity. This study provides a critical account of the current standard practice and presents an approach that takes into consideration both the spatial context of rainfall storms, and indirectly incorporates runoff to produce a representative approach to assessing urban rainfall storm severity in terms of flood potential. A stepwise regression analysis was performed on a dataset of individual rainfall storm characteristics to best represent documented basement floodings in the City of Edmonton. Finally, the urban rainfall storm flood severity index was shown to be most representative of the documented basement floodings' severity when compared to that of the IDF method.
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