Environmental Engineering Commons^™

A Two Dimensional Distributed Hydrological Model For Infiltrating Watersheds With Channel Networks, Donald Lee Currey

Civil & Environmental Engineering Theses & Dissertations

A numerical model named Old Dominion Watershed Simulation Model (ODWSM) is developed for simulating the rainfall/runoff process that occurs over watersheds. ODWSM's computational modules include the capability to simulate two-dimensional overland flow, spatially varied infiltration and depression storage, interception and channel flow for irregular and looped networks.

Overland flow computation is performed by writing the two-dimensional kinematic wave equations in an implicit finite difference form. Computational speed is gained by using an upwind differencing scheme and solving the equations in the direction of flow. This solution method allows for the calculation of infiltration and depression storage to include rainfall, current …

A Calibrated Shoreline Change Model For The Southeast Atlantic Ocean Coast Of Virginia, Prasert Vangsantitrakul

Civil & Environmental Engineering Theses & Dissertations

The idea that the long-term historic shoreline change at a given site is mainly caused by spatial gradients in the net longshore sediment transport is generally accepted. The position changes of the coastline can therefore be modeled by calculating the coastal erosion or accretion from the longshore sediment transport. This study used the GENESIS software program, one-line model, to simulate and calibrate the long-term shoreline change of the southeast coast of Virginia from 1925 to 1980. The study reach covers 45- km from Cape Henry to the Virginia-North Carolina border.

This study experienced the lack of certain important historic data …

Evaluation Of Toxicity, Bioavailability And Speciation Of Lead, Zinc And Cadmium In Mine/Mill Wastewaters, Mujde Erten-Unal, Bobby G. Wixson, Nord Gale, Jerry L. Pitt

Civil & Environmental Engineering Faculty Publications

The toxicity of common compounds of lead, cadmium and zinc was evaluated in waters similar to that found in the world's largest lead producing area in Missouri. Static, acute toxicity tests were performed using fathead minnows (Pimephales promelas) and water fleas (Daphnia magna) respectively. Test organisms were subjected to varying amounts of sulfide, carbonate, chloride and sulfate salts of lead, zinc and cadmium mixed in hard, alkaline waters typical to this region. Median lethal concentrations were calculated using nominal versus measured metal concentrations. Measured metal concentrations included four different metal fractionation (extraction/filtration) techniques at different pH …

The Detoxification Of Petroleum Contaminated Coastal Plain Sandy Soil Using An Amended Vermicomposting Approach, John Charles Kraemer

Health Services Research Dissertations

This study explores the feasibility of utilizing an amended vermicomposting treatment approach for detoxifying petroleum hydrocarbon contaminated sandy soil. The bench-scale testing of gasoline and diesel contaminated soil using three test soil vessels and one control soil vessel was performed in a laboratory setting for a six week time period. The control soil received no treatment other than distilled water to maintain soil moisture. Treatment 1 consisted of direct application of liquid municipal biologic sludge on a weekly basis. Treatment 2 consisted of the addition of 30 Eisenia foetida earthworms and distilled water. Treatment 3 consisted of direct application of …

Characterization Of Rainfall Runoff Quality From A Shipyard Drydock, Peter Pommerenk

Civil & Environmental Engineering Theses & Dissertations

Water quality and hydrological data were collected during seventeen rain events and additional data was obtained from laboratory experiments to characterize the quality of stormwater runoff from a drydock located on the Elizabeth River in Norfolk, Virginia.

The results indicated that the concentrations of dissolved constituents in drydock runoff increased with decreasing flow rate, while solids concentrations exhibited positive correlation to flow rate, suggesting that the mobilization of particulate matter is velocity driven. Approximating the runoff hydrograph due to a storm event using a simple model enabled derivation of the average time that rainwater resides on the drydock surface before …

Modeling A High-Efficiency Ozone Injection Contactor, L. Bernard Garrett Jr.

Civil & Environmental Engineering Theses & Dissertations

Significant research over the last several years has focused on applying modeling equations for estimating design parameters of ozone contactors. Much of this research has focused on fine bubble diffusers, which are the more widely used injection system for ozone contactors in the U.S. A recently developed design incorporates a new ozone injection system called a sidestream venturi injector (SVI) which is used with a co-current downflow column to achieve very high ozone mass transfer efficiencies. A pilot study conducted at the Harwood's Mill water treatment plant in Newport News, Virginia, from June to December 1993 demonstrated the high mass …

Long-Term Effects Of Seawalls On The Adjacent Nonwalled Beaches Of A Historically Receding Shoreline, Bryan Norton Jones

Civil & Environmental Engineering Theses & Dissertations

Great debate has arisen in recent years over the effects seawalls may or may not have on the erosion rate of a historically receding shoreline. A primary obstacle to the formation of definite conclusions about this subject is the lack of long-term physical data, which must be collected prior to and following seawall construction. This thesis presents the results of a study using 15 years of beach profile data to determine how seawalls influence the existing erosional trends of the beach at Sandbridge, Virginia.

Three analysis methods using three time scales (historic, seasonal, and storms) were used to answer three …

Organic Matter Characterization Of Virginia Rivers And Reservoirs, Susanne Margaret Lockhart

Civil & Environmental Engineering Theses & Dissertations

Research was conducted on characterizing the DOC characteristics and to discern whether spatial and temporal variations exist in these characteristics as impacted by seasonal, hydrologic or other factors. Data was cumulative of two studies: the State-Wide Survey in which water samples were taken in March and July 1995 from surface waters in four physiographic regions of Virginia and the James River Peninsula Survey concentrating on reservoirs and rivers on the James River Peninsula.

Results illustrate that the two largest fractions of DOC were the hydrophilic and hydrophobic acid fractions. An increase in DOC was observed between the mountains and the …

A Receiving Water Quality Model For Dissolved Metal Runoff From A Floating Drydock, Thomas O. Fenn

Civil & Environmental Engineering Theses & Dissertations

A methodology for modeling the water quality mixing zone of dissolved metal bearing storm water runoff is presented with specific application to floating drydocks in a tidal estuary. The method relies upon a solution of the mass balance equation as contained in the computer program, Water Quality Analysis Simulation Program (WASPS), an Environmental Protection Agency (EPA) model. Separate applications are presented for dissolved metal and solid settling to optimize the WASPS program capabilities.

WASPS provides the capability to evaluate the mass balance equation in a finite difference scheme applied over a large number of small volume segments. The program may …

The Influence Of Seawalls On Beach Responses To Storms, Seasonal Transitions And Long-Term Erosion, John Marshall Hazelton

Civil & Environmental Engineering Theses & Dissertations

It has been argued that seawalls have a detrimental effect on the adjacent beaches. These effects may only be noticeable over a period of years or may be short-term effects associated with storms or with seasonal transitions of the beach. Many theories on beach and seawall interaction have been speculative and have lacked actual field or laboratory evidence for their basis.

This study uses four years of monthly and post-storm beach profile data to examine what influences the seawalls at Sandbridge, Virginia have on the adjacent beaches. Long-term effects of the seawalls are analyzed using fourteen years of profile data. …

Landfill Leachate Production And Gas Generation Numerical Model, John Edward Riester Jr.

Civil & Environmental Engineering Theses & Dissertations

Numerous processes occur in landfills which lend themselves to modeling. Many of the processes are mutually interdependent. An unsteady numerical model is developed combining the major processes. The three-dimensional moisture transport equations and boundary conditions are solved using an implicit finite difference scheme. The boundaries are determined through a two-dimensional runoff model for the landfill surface and a one-dimensional leachate liner flow model at the bottom of the landfill. The runoff model accounts for evapotranspiration, runoff, infiltration, and leachate recirculation. Richard's equation is solved for saturated and unsaturated vertical flows and Darcy's Equation is solved for lateral flow between adjacent …

Statistical Variations In Beach Parameter Change Rates For Walled And Non-Walled Profiles At Sandbridge, Virginia, Douglas Allen Bellomo

Civil & Environmental Engineering Theses & Dissertations

The interaction of seawalls {bulkheads) and beaches is a highly controversial subject today. In many locations all over the United States, seawalls have been both praised and ridiculed. It is well documented that Sandbridge, Virginia is, and has been, experiencing shoreline recession. Many believe however, that the recent construction of the seawalls has worsened this existing situation.

Fortunately, historical maps, and beach profiles are available to help determine if this is truly the case. The following defines several visible beach parameters, and describes how these parameters were calculated from two different data sources. Several methods and statistical techniques are then …

Evaluating The Effects Of Alum With Polyelectrolyte Coagulant Aids In Treatment Of Low Turbidity Waters, Kenneth John Stockwell

Civil & Environmental Engineering Theses & Dissertations

Potable water sources usually require treatment for removal of suspended organic and inorganic particles. Conventional treatment processes incorporate chemical coagulants for removal of these suspended particles. Alum is a widely used coagulant that can provide adequate removals of turbidity. However, high alum dosages are required for treatment of low turbidity waters producing a voluminous sludge that is difficult to dewater.

Recent Federal regulations have limited disposal options for chemical sludges. This has prompted a reevaluation of coagulants and their dosages with the goal of reducing the amount of sludge produced and improving the sludge handling characteristics necessary for ultimate disposal. …

An Engineering Solution To Improve Water Quality In A Tidal Lagoon, Richard Warren Price

Civil & Environmental Engineering Theses & Dissertations

Rising demand for better water quality stimulated research and development of ways to improve the quality level in existing as well as proposed water systems. At present, most of the solutions focus on biological and chemical processes.

Many natural or man-made water bodies act as receivers for both point and non-point pollution sources. Employment of biological and chemical treatment has proved successful in many of these cases; however, in some cases a more natural physical solution of an engineering mode would be more desirable. A "flushing" technique using the tidal fluctuation as a driving force has been investigated and the …