Browsing by Author "Elliott, Mark A."

Now showing 1 - 7 of 7
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    Analysis of the impacts of drinking water infrastructure on water quality in Alabama's Black Belt
    (University of Alabama Libraries, 2013) Forehand, Richard Warren; Johnson, Pauline; University of Alabama Tuscaloosa
    Research has suggested that residents of Alabama's Black Belt are at elevated risk of waterborne disease due to a problem with failing septic tanks in the area. At the same time, cities and towns across the nation are realizing the dire need for replacing and rehabilitating America's declining water infrastructure to protect public health. An EPA-STAR project is being conducted in three Black Belt counties to further assess the situation and help local water utilities combat the increased risk of contamination. Water loss, low pressure, low chlorine, high residence time, and presence of total coliforms were used as indicators to assess which service areas of one Black Belt system were most likely vulnerable to contamination. Collected data from 195 households within the system and simulated data from an EPANET model of the system were used for the analysis. The results identified the regions with the highest prevalence of these indicators and suggested further system level sampling to evaluate if the problem is more associated with system water mains or households.
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    Climate variability and southeast U.S. precipitation
    (University of Alabama Libraries, 2018) David, Christopher LeBlanc; Tootle, Glenn A.; University of Alabama Tuscaloosa
    A study of the seasonal effects of interannual and interdecadal climactic influences on southeast U.S. precipitation is presented. Precipitation data was gathered from 183 precipitation gauges provided by The National Oceanic and Atmospheric Administration’s (NOAA) National Center for Environmental Information (NCEI). The phases (warm/positive or cold/negative) of oceanic-atmospheric influences of the Pacific Ocean [El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)] and the Atlantic Ocean [Atlantic Multidecadal Oscillation (AMO)] were identified for the preceding year (1969-2013) to the precipitation data (1970-2014). Three statistical significance tests (1) two-sample t-test (90% significance), (2) rank-sum (90% significance) and (3) effect-size (threshold of 0.8 to -0.8) were used to evaluate precipitation response to the positive/negative phases of the oceanic-atmospheric influences of the Pacific and Atlantic Oceans. The warm phases of ENSO and PDO were associated with increased annual precipitation in the southeastern region of the United States, while the cold phase of the AMO was associated with increased annual precipitation. While providing affirmation of these associations, this study considers the variation in seasonal precipitation of the southeastern U.S. The results indicate strong winter [January-March (JFM)] signals by all three oceanic-atmospheric influences and a strong summer [July-September (JAS)] signal by the PDO.
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    Expert systems for disaster forecasting warning recovery and response in water resources management
    (University of Alabama Libraries, 2017) Zhang, Xiaoyin; Moynihan, Gary P.; Ernest, Andrew N. S.; University of Alabama Tuscaloosa
    Disaster forecasting, warning, recovery, and response in water resources management require the application of knowledge from a diverse range of domains. Identifying the appropriate approach necessitates integrating rules and requirements from these knowledge domains in such a way that the operational goals are achieved with minimally available situational information. Disaster forecasting, warning, recovery, and response must be able to adapt and evolve as new information becomes available. To date, there has been a limited amount of work developing expert systems in this area. In order to fill the knowledge gap, this study 1) identifies and assimilates the knowledge necessary for Water Distribution Network (WDN) decontamination, local flood forecasting and warning, and local flood response coordination and training; 2) determines the relative utility of architectures of expert systems and conventional codes; 3) evaluates the relative benefits of forward and backward chaining inferential logic in these scenarios. Based on the outcome of the conceptual systems, we develop three complete backward chaining expert systems, respectively. With extensible knowledge bases combined with the information provided by the users, the expert systems successfully provide reasoning routines, recommendations, and guidance on disaster forecasting, warning, recovery, and response in water resources management.
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    Global scale bedload flux modeling
    (University of Alabama Libraries, 2018) Islam, Md Tazmul; Cohen, Sagy; University of Alabama Tuscaloosa
    Bedload flux is an important component of the total fluvial sediment flux. Bedload dynamics can have a substantial effect on rivers and coastal morphology, infrastructure sustainability, aquatic ecology and water availability. Bedload measurements, especially for large rivers, are extremely scarce worldwide, where most global rivers have never been monitored. The paucity of bedload measurements is the result of 1) the nature of the problem (large spatial and temporal uncertainties), and 2) high costs due to the time-consuming nature of the measurement procedures (repeated bedform migration tracking, bedload samplers). Numerical models can help fill measurement gaps and provide a framework for predictions and hypothesis testing. Here, I present a first of its kind global bedload flux model using simplified Bagnold Equation, which considers only two dynamic (discharge and river slope) parameters along with few constant parameters (e.g., gravity, sediment density). Evaluation of model has been done based on observations for 59 river locations, mostly in the U.S. The model parameters, as well as other influential fluvial and basin parameters (e.g., discharge, drainage area, lithology), were evaluated against observed bedload to find their potential influence on bedload prediction. Considering the simplicity in the parameters needed to predict bedload flux through this model, and the capabilities to give first order estimation the model is helpful to give the large-scale overview of dynamic bedload flux universally. Also, the longitudinal dynamics between suspended and bedload sediment fluxes are mapped in three large rivers.
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    Modelling the Potential Benefits of Irrigation with Nutrient-Rich Treated Municipal Wastewater Effluent for Growth of Loblolly Pine
    (University of Alabama Libraries, 2021) Gunaydin, Serhat; Elliott, Mark A.; University of Alabama Tuscaloosa
    This thesis research was initiated in the context of a wastewater management project in rural Alabama to investigate whether irrigation of loblolly pine (P. taeda) with nutrient-rich effluent generated by decentralized wastewater treatment systems could benefit the local forestry industry while addressing the wastewater management needs of underserved rural communities. In this study, the benefits of irrigation are considered in the local context based on recent years with actual precipitation, all wet years, and all dry years. Influent wastewater with nitrogen concentrations representative of the high, medium, and low strength municipal wastewater were included. Scenarios were tested for wastewater influent streams treated with three different nutrient removal levels relevant for decentralized wastewater treatment systems and representative of a range of nitrogen-removal performances. The growth of loblolly pine on the study site, modeled in FASTLOB annually for volume and mass over five-year intervals, is reported for all of these conditions (precipitation, influent wastewater strength, wastewater treatment efficiency) and compared with equivalent irrigation practices with pure water containing no nutrients. Irrigation with nutrient-rich wastewater treatment effluent yielded substantial benefits to loblolly pine growth (volume and mass) under all conditions tested. Over five years of growth, tree volume increased was 12.53% to 26.66 % greater with nitrogen plus phosphorous compared to irrigation with no nutrient; likewise, tree mass increased between 28.04% to 71.91% more. The greatest benefits to growth were modeled under low precipitation conditions, with poorly performing wastewater treatment technologies and high strength influent wastewater, because they yielded the highest net nitrogen loadings. It was observed that irrigation provided a higher contribution than expected. Even in the worst scenario in terms of fertilization, growth showed a significant increase. The study results show that this application will both increase land productivity and have positive effects on a big problem such as treated wastewater discharge.
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    Source area processes contributing to microbiological quality of stormwater
    (University of Alabama Libraries, 2017) Wilson, Bradford Munro; Pitt, Robert; Elliott, Mark A.; University of Alabama Tuscaloosa
    A literature review reveals a need by water managers for a model by which the regulatory impacts likely to result from stormwater runoff of fecal indicator bacteria previously defecated onto the landscape, under conditions extant within their jurisdiction, might be predicted. Though the literature provides little information as to what the needed model might look like, it also contains much in the way of relevant general sciences that, by means of logical analysis, provides a hypothetical framework by which the significance of likely parameters of such a model might be piecewise tested. I present exploratory research into the feasibility of constructing such a model. The research presented consists of a series of scoping studies, in article style, designed to separately probe the relevance, important parameters, and significance of separable putative sequential processes by which such a model might eventually be constructed, and provide guidance informing future research.
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    Straight pipes and household wastewater discharges into the rural Alabama and impact on watershed water quality with wetland land-uses
    (University of Alabama Libraries, 2017) Aytekin, Erdogan; Elliott, Mark A.; University of Alabama Tuscaloosa
    In rural areas, untreated wastewater discharged from homes (commonly called “straight pipes”) can cause harmful effects on the region’s rivers, streams and lead to negative impacts on water quality and potentially ecological and human health. Determining and addressing the water quality and health of these aquatic ecosystems requires identification of the source of contamination. Surface water quality in Hale County was evaluated at least once a month at twenty sites in wet and dry seasons. Samples were analyzed for physical (turbidity), chemical (pH, conductivity, chloride, sulfate, calcium, iron, magnesium, potassium, sodium, ammonium, ortho-phosphorus, nitrite, nitrate, dissolved organic carbon, optical indices), and microbiological (E. coli) water quality parameters. Excitation-emission matrixes (EEMs) Parallel Factor Analysis (PARAFAC) was used to identify and classify fluorescence emitting organic substances based on fluorescence peak location. Three fluorescence components, terrestrial humic-like, microbial humic-like, and protein-like fluorophores were identified using the EEM-PARAFAC model. Principal component analysis (PCA) was used to identify analyte signatures associated with sewage contamination. The PCA (varimax rotation) identified three primary components (Eigenvalue >1), accounting for 40.4%, 19.0% and 8.7% of total variance respectively. In order to detect straight pipe wastewater impacts on water quality, three main sites were sampled upstream, midstream and downstream of the town of Newbern, Alabama over the three months of the drought period (i.e., from September to November 28th, 2016). Over 20 water quality parameters were analyzed and compared with the WHO, EPA, and ADEM standards. The results showed that E. coli values highly exceed water quality standards, particularly after the drought when peak E. coli concentrations downstream exceeded 100,000 per 100 mL. This study also investigated the impacts of wetland land use on stream water quality response at eight main sites. The results showed that potassium (R square 0.78), C3 (R square 0.58) and optical brighteners (R square 0.53) correlated positively with percent wetland in the draining watersheds. This study is one of the first to document the adverse impacts of straight pipe discharges on water quality in the United States.