Thesis (M.S. in civil engineering)--Washington State University. / Includes bibliographical references.

Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 291-296).

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

For temperate lakes which receive a variable nutrient loading with seasonal variance in their hydrology, it is necessary to consider the dynamic response of the lake to these variable nutrient loadings. An approach to evaluate Lake Eola water quality responses to dynamic discharge of nutrients is presented. The major source of nutrients for this lake is stormwater runoff containing nitrogen and phosphorus. A mass balance of nutrient sources and sinks for the period of one year (April 1980 - March 1981) was performed. To accomplish this, a field determination for various parameters of the hydrologic budget was performed on a monthly basis. A monthly water quality analysis of the lake was measured. It was determined that Lake Eola was phosphorus limited and that 87% of the Total Phosphorus entering the lake via stormwater runoff was retained in the bottom sediments. Retention of various nutrients ranged from 77% to 93%. In order to evaluate the dynamic response of this lake, it was necessary to consider the retention of the nutrients as a function of time. The inductive methodology for this analysis and an example for Total Phosphorus is presented.

This study was designed to investigate the indicator bacterial densities in runoff from urban and rural sources and to compare these densities with the densities in both raw and secondary-treated, unchlorinated sewage effluents. Analysis was performed on a total of 42 samples, 22 of which were taken at the urban and the rural sites and correlated with storm flow. The remaining 20 samples were taken, 5 at each of the 4 sites, in order to establish respective baseline densities for total coliform, fecal coliform, and fecal streptococcus. Results indicated that mean values for total coliforms and fecal coliforms during dry flow were within Virginia State standards for urban runoff, but exceeded those two standards 100 percent and 91.9 percent of the time, respectively, during storm flow conditions. Mean values for total coliforms and fecal coliforms during dry flow at the rural site exceeded Virginia State standards 100 percent and 75 percent of the time, respectively. During storm flow the standards for both of these indicators were exceeded 100 percent of the time. It was also determined that the increase in densities typically lagged behind flow increases and maintained this lag while returning to baseline values. Finally, the FC/FS ratio as originally proposed by Geldreich was statistically supported as being valid for use in the identification of fecal pollution sources. Individual ratios were less than 0.7 at the urban watershed for 80% of the dry flow samples and 64.6 percent of the storm flow samples. For the rural site, FC/FS ratios were less than 0.7 for 25 percent of the dry flow samples and 81.8 percent of the wet flow samples. Samples of raw and secondary treated sewage exhibited ratios above 4.0, 40 percent, and 25 percent of the time respectively. / Master of Science

Laboratory-scale settling units were used to determine the degree of treatment that could be achieved by sedimentation of stormwater runoff. Seven runoff samples were collected from shopping centers, which were selected because of their large impermeable surfaces resulting in high pollutant concentrations. The sampling sites were also representative of locations where detention basins would be constructed to control runoff flows and/or sediment loads. Approximately twenty liters of stormwater runoff were placed in each of four Plexiglas columns, and samples were withdrawn from column sampling ports immediately following sample addition, and after two, six, twelve, twenty-four, and forty-eight hours. The settling of the first runoff sample collected was terminated after only twenty-four hours. Sampling depths along the column, were either at one, two, and three feet, or at one, two, and four feet. Each sample was analyzed for total and volatile suspended solids, total and soluble Kjeldahl nitrogen, total and soluble phosphorus, orthophosphate, ammonia, oxidized nitrogen fonns (nitrites and nitrates), the particle-size distribution, and six heavy metals. Organic matter and total and fecal coliform bacteria were also measured but with less frequency. Dissolved oxygen measurements were made during settling of two of the seven experiments. Sedimentation reduced the concentration of most pollutants significantly, although pollutant concentrations composed mainly of soluble forms were not readily removed. Also examined was the use of settling data for determining particle removals in basin design criteria by the relationship between the reduction of particle surface area and various pollutants. The greatest majority of surface area in the runoff samples was associated with particles that were between 15 to 35 microns in diameter. / M.S.

by Wan Yuk-ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 146-152). / Abstracts in English and Chinese. / List of Tables --- p.i / List of Figures --- p.iii / List of Plates --- p.v / Chapter CHAPTER I --- INTRODUCTION / Chapter 1.1 --- Scope of the Problem --- p.1 / Chapter 1.2 --- Importance of the Urban Sediments on the Environment --- p.8 / Chapter 1.3 --- Hydrological and Sedimentological Problems Related to Urbanization -a Storm Event Basis --- p.13 / Chapter 1.4 --- Studies in Sub-tropical Humid Areas --- p.17 / Chapter 1.5 --- Objectives of this Research --- p.18 / Chapter CHAPTER II --- CHARACTERISTICS OF URBAN SEDIMENTS / Chapter 2.1 --- Sediments Transportation Pattern of Storm Events --- p.19 / Chapter 2.2 --- Particle Size Parameter --- p.29 / Chapter 2.3 --- Volatile and Chemical Parameters of Total Sediment Loading --- p.33 / Chapter 2.4 --- Problems Arisen from the Review of Previous Studies and Directions --- p.36 / Chapter CHAPTER III --- METHODOLOGY / Chapter 3.1 --- Experimental Design --- p.37 / Chapter 3.1.1 --- Catchment Approach --- p.38 / Chapter 3.1.2 --- Storm base Approach --- p.39 / Chapter 3.2 --- Study Area --- p.41 / Chapter 3.2.1 --- Rainfall Pattern --- p.41 / Chapter 3.3 --- Nature of the Study Areas --- p.44 / Chapter 3.3.1 --- Location --- p.45 / Chapter 3.3.2 --- Relief and Geology --- p.47 / Chapter 3.3.3 --- Landuse Pattern --- p.49 / Chapter 3.3.4 --- Climatic Condition --- p.57 / Chapter 3.3.5 --- Streamflow Measurement --- p.59 / Chapter 3.4 --- Suspended Sediment Concentration --- p.61 / Chapter 3.4.1 --- Sample Collection --- p.61 / Chapter 3.4.2 --- Laboratory Procedures --- p.62 / Chapter 3.4.3 --- Instantaneous Sediment Concentration --- p.63 / Chapter 3.5 --- Volatile and Mineral Solids --- p.63 / Chapter 3.6 --- Particle Size Measurement --- p.65 / Chapter CHAPTER IV --- TRANSPORTATION PATTERN OF STORM SEDIMENTS IN URBAN CATCHMENTS / Chapter 4.1 --- Introduction --- p.66 / Chapter 4.2 --- Suspended Sediment Transport Patterns During Storm Events --- p.70 / Chapter 4.3 --- The Relationship Between Discharge and Instantaneous Sediment Concentration --- p.81 / Chapter 4.4 --- Additional Factors Affecting Instantaneous Sediment Concentrations During Storm Events --- p.87 / Chapter 4.4.1 --- University Campus --- p.88 / Chapter 4.4.2 --- Fo Tan --- p.91 / Chapter 4.5 --- Discussion --- p.93 / Chapter CHAPTER V --- SEDIMENT CHARACTERISTICS / Chapter 5.1 --- Introduction --- p.97 / Chapter 5.2 --- Characterization of Sediments --- p.98 / Chapter 5.3 --- Variations in Sediment Size --- p.101 / Chapter 5.3.1 --- Between-Storm Variations in Particle Size --- p.103 / Chapter 5.3.1.1 --- Size Distribution Curves --- p.103 / Chapter 5.3.1.2 --- Median Particle Size --- p.107 / Chapter 5.3.2 --- Within-Storm Variations in Particle Size --- p.108 / Chapter 5.3.3 --- Factors Affecting the Between Storm Variations in Sediment Particle Size --- p.120 / Chapter 5.4 --- Variations in the Sediment Volatile Content --- p.123 / Chapter 5.4.1 --- Differences in Sediment Volatile Content Between the Two Catchments --- p.123 / Chapter 5.4.2 --- Variations in Volatile Content Between and Within Storms --- p.124 / Chapter 5.4.3 --- Timing of the Volatile Content Peaks --- p.128 / Chapter 5.4.4 --- Factors Affecting the Volatile Content --- p.131 / Chapter 5.4.5 --- Some General Observations on Sediment Volatile Content --- p.133 / Chapter 5.5 --- Summary and Discussion --- p.133 / Chapter CHAPTER VI --- CONCLUSION / Chapter 6.1 --- Summary of Findings --- p.137 / Chapter 6.2 --- Implications of the Research Findings --- p.141 / Chapter 6.3 --- Limitations of this Study and Suggestions for Future Work --- p.143

Green Stormwater Infrastructure (GSI) has become a popular method for flood mitigation as it can prevent runoff from entering streams during heavy precipitation. In this study, a recently developed neighborhood in Gresham, Oregon hosts a comparison of various GSI projects on runoff dynamics. The study site includes dispersed GSI (rain gardens, retention chambers, green streets) and centralized GSI (bioswales, detention ponds, detention pipes). For the 2017-2018 water year, hourly rainfall and observed discharge data is used to calibrate the EPA's Stormwater Management Model to simulate rainfall-runoff dynamics, achieving a Nash-Sutcliffe efficiency of 0.75 and Probability Bias statistic of 3.3%. A synthetic scenario analysis quantifies the impact of the study site GSI and compares dispersed and centralized arrangements. Each test was performed under four precipitation scenarios (of differing intensity and duration) for four metrics: runoff ratio, peak discharge, lag time, and flashiness. Design structure has significant impacts, reducing runoff ratio 10 to 20%, reducing peak discharge 26 to 68%, and reducing flashiness index 56 to 70%. There was a reverse impact on lag time, increasing it to 50 to 80%. Distributed GSI outperform centralized structures for all metrics, reducing runoff ratio 22 to 32%, reducing peak discharge 67 to 69%, increasing lag time 133 to 500%, and reducing flashiness index between 32 and 62%. This research serves as a basis for researchers and stormwater managers to understand potential impact of GSI on reducing runoff and downstream flooding in small urban watersheds with frequent rain.

Thesis (M.E.S.)--Evergreen State College, 2003. / Title from title screen viewed (4/15/2009). Includes bibliographical references (leaves 56-58).

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.