Diversion of the first flush of storm runoff to a detention basin for pollutant removal is an efficient way to control nonpoint source pollutant in urban areas. This can be achieved by a diversion box and detention basin system. To numerically simulate the response of the system to a design rainfall event and the associated pollutant loadings for a given drainage area, a desk top model has been developed for"user-friendly"' 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 outflow and pollutant concentration for urban stormwater quality and quantity management. This model is designed for both the analysis and design of the system. / M.S.

Laboratory-scale settling columns were used to determine the settling velocity distributions of suspended solids to refine a methodology selected by the FHWA in designing wet detention basins for the treatment of highway stormwater runoff. Thirteen runoff samples were collected, over two years, from high volume (greater than 100,000 vehicles per day) highways in the Northern Virginia area. The sampling sites drained only highways and associated rights-of-way. Approximately 5.5 gallons of stormwater were placed in Plexiglass columns, and samples were withdrawn from column sampling ports immediately following sample addition, and after two, six, twelve, twenty-four, and forty-eight hours. Sampling depths along the column, were at one, two, and three feet from the base of the column. Each sample was analyzed for total suspended solids, five total and dissolved heavy metals, total Kjeldahl nitrogen, nitrate-nitrite nitrogen, total and dissolved phosphorus, and pH. Orthophosphorus, temperature, and total dissolved solids were analyzed only during the first year. The resulting analysis determined that highway runoff is similar to urban runoff in distribution and settling characteristics. Correlations between suspended solids removal and the removal of other pollutants were developed. The settling velocity distribution found in this study resulted in the revision of the FHWA design methodology for wet detention basins. / Master of Science

One of the major programs to abate the deterioration of water quality in the Lake Okeechobee watershed was the addition of detention-retention facilities. The microbial biochemical potential of two different detention-retention marshes in the Kissimmee River Valley were examined to determine their effectiveness to improve water quality. The kinetics of decomposition and nutrient mineralization and assimilation, as mediated by microorganisms, and the enumeration of microorganisms capable of utilizing various substrates were studied. Various communities within each marsh were studied during a 2-year period. The decomposition rates of 3 plant substrates were determined. Chitin was used as a standard for organic decomposition. Chitin had significantly higher (p< 0.05) rates of decomposition than the plant material in all sites at both marshes. Chitin decomposition rates were significantly different (p< 0.05) between sites. Significant differences (p< 0.05) in rates of decomposition were also found between the 3 plant substrates. the difference in decomposition rates for the 3 plant substrates existed within sites, as well as between sites. The number of microorganisms and the mineralization and assimilation rates were significantly different (p< 0.05) between the detention-retention marshes. Significant differences (p< 0.05) in numbers of microorganisms and rates were also found between sites within each marsh. The variation in detrital processing demonstrated that site-specific dynamics occurred in the detention-retention marshes. Higher decomposition rates were associated with sediment sites containing organic matter with either a continuous, shallow flow of water or alternate wet/dry periods. Decomposition rates were lowest at sites containing sandy sediments, and dry soil sites without a flow of water. Higher aerobic and anaerobic bacterial activity was also associated with sediment sites containing organic matter with either a continuous, shallow flow of water are alternate wet/dry periods. Higher fungal activity was associated with alternate wet/dry sediment sites, but only during dry periods. Microbial activity was lowest at sites containing sandy sediments and in water columns.

A system of detention basins is an effective device for control of, storm flood both in terms of quantity and quality. The feasibility of designing detention basins for flood control by use of abandoned spaces near highway interchange and between highway embankments is investigated. Three algorithms are examined for routing inflow hydrographs through interconnected basins under various hydraulic and. hydrologic conditions. The programs solve for both the time dependent flow quantities and the extent of pollutant removal in the system for given inflows and pollutant trap efficiencies of the individual basins. The first algorithm is the extended version of the classical single reservoir routing and involves solution of a system of simultaneous nonlinear equations. The other two algorithms employ the so-called linearized or simplified versions of the continuity equation. The algorithms can take care of various possible combinations of inflow, type of connections between basins, and the boundary conditions at the outlet(s). Results from the three algorithms are comparatively analysed and the one which does not require excessively small time step for solution convergence is selected. The Kuo method employing the standard approximation for the mass conservation equations as in classical single reservoir routing is found favorable with respect to the time step required for convergence and hence is selected for application to design examples. Various basin arrangements are included to show the routing results with respect to quantity and quality for different combinations of storm inflows and outlet structure types. Interconnection between basins is found desirable both in terms of quantity and quality control of effluent. / M.S.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 1997 / Detention storage IS a well tested, and generally accepted, method of attenuating flood hydrographs, but relatively littlo data is available from the monitoring of full scale instc'lations An onstrearn pond was constructed at Sunninqhill Park and details of 15 inflow and outflow hydro [Abbreviated Abstract. Open document to view full version] / MT2016

Modern urban stormwater infrastructure includes vegetated bioretention facilities (BRFs) that are designed to detain water and pollutants. Phosphorus (P) is a pollutant in stormwater which can be retained in BRF soils in mineral, plant, and microbial pools. We explored soil properties and phosphorus forms in the soils of 16 operational BRFs in Portland, OR. Since soil hydrology can significantly impact P retention, we selected BRFs along an infiltration rate (IR) gradient. We conducted sequential fractionation and tests of P pools and measured P release in a subset of soils after drying and flooding samples for ten days. We hypothesized that mineral or organic soil P forms would be correlated with IR, and that vulnerability to P release would depend on the interaction of drying and flooding treatments with P forms and pools. IR did not significantly explain differences in P forms. Soil TP was elevated across all sites, compared with TP in agriculturally-impacted wetlands and was substantially composed of soil organic matter (OM)-associated P. Phosphorus sorbed to mineral Fe and Al oxides- was variable but positively correlated with water-extractable P. The concentration gradient of water-extractable P was primarily controlled by overall P pools. Experimentally induced P releases were seen in 5 of 6 soils exposed to drying conditions, presumably released through microbial mineralization of OM. Only one site showed significant P release following the flooding treatment. Our measurements supported the idea that Fe and Al oxides provide P sorption capacity in these BRF soils. Variable inputs of P to BRFs through stormwater and litterfall may contribute to variability in P profiles and P release vulnerability across sites. Design specifications and management decisions relating to bioretention soils (e.g. establishment of acceptable soil test P levels, focusing on P forms known to influence vulnerability of P release) may benefit from detailed biogeochemical investigations.

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Thesis (M.Eng.Sc)--University of Adelaide, Dept. of Civil and Environmental Engineering, 2000? / Bibliography :leaves 158-171. A monitoring program, funded by the South Australian government (through the former MFP Development Corporation), was established to monitor the quality and quantity of storm water entering and leaving the wetland. This study formed part of the funded program. Simple regression models were developed; and will assist in the monitoring of performance of the wetland to alleviate the pollutant load into the Barker Inlet.

Thesis (M.Eng.Sc.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 2000? / Corrigenda pasted onto front end-paper. The CD contains Excel spreadsheets containing data collected. Bibliography: leaves 209-222.

My deepest respect and appreciation are extended to Dr. L. Gray Wilson for providing the opportunity to conduct this research, for his advice and assistance during the course of the research, and for his review of and suggestions for improving this manuscript. I would also like to thank Michael Osborn for his assistance. This research was funded by the City of Tucson. The assistance and direction provided by Mt. Bruce Johnson and Mt. Joe Babcock at Tucson Water are gratefully acknowledged. My thanks are also extended to Dr. Daniel D. Evans, Dr. L.G. Wilson, and Dr. Stanley N. Davis for serving on my thesis committee. Bruce Smith's assistance is gratefully acknowledged. Bruce spent two long days with 110-degree temperatures In a parking lot describing the lithology of sediment samples collected during the drilling phase of this research. He also determined the moisture content and particle size distribution on samples collected from the borehole. The assistance of Ralph Marra and Steve Brooks is also gratefully acknowledged. Ralph waded through city and county bureaucracies to determine zoning at each dry-well site. Steve assisted with collecting dry-well settling chamber sediment samples.