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.

The increasing interest in adaptive models of governance and adaptive tools for management stems from a recognition that the traditional paradigm in natural resource management is failing to adequately maintain the resilience of social-ecological systems. A principal reason for this failure is that each problem is treated discretely by approaches that are characteristically narrow and reactive rather than comprehensive and forward-looking. This lack of sophistication means that traditional governance models are unsuitable for dealing with the inherent uncertainty characteristic of environmental problems, and for dealing with the conflicts that emanate from the social construction of those problems. The challenge presented by these uncertainties and conflicts illuminates deficiencies in how we conceptualize the dynamics of social-ecological systems and how we formulate approaches to policy and problem solving to cope effectively with those dynamics. What changes in governance could remedy these deficiencies with more effective forms of collective action that sustain and enhance social-ecological resilience? My purpose was to pursue those changes with an examination of the human dimension of governance, with specific reference to the Great Lakes and potential features of an adaptive paradigm for the Great Lakes Water Quality Agreement. The goals of this research were to contribute knowledge and perspective on our understanding of and progress towards adaptive Great Lakes governance, and secondly, to generate pragmatic and actionable policy options for enhancing participatory processes, social learning, and leadership for adaptive Great Lakes governance. To achieve these goals, I sought the following specific objectives: (1) identify aspects of the Agreement that would compel a more rigorous and evaluative approach to policy development and implementation in the Great Lakes; (2) acquire evidence to characterize deficits in the implementation of Great Lakes policy; (3) acquire evidence to characterize pathologies in the management of the Great Lakes; (4) (i) identify, detail, and combine the principles and processes of adaptive management and decision analysis, (ii) relate these mechanisms to policy and research in the Great Lakes context, especially where such mechanisms for managing in the face of uncertainty could ameliorate implementation deficits and management pathologies; and (5) (i) acquire evidence of the strengths and limitations in the development and implementation of Great Lakes Remedial Action Plans from people with direct experience with RAPs, (ii) identify and characterize potential reforms that could improve the design of community-based, nearshore restoration programs, and (iii) measure the desirability, feasibility, and likelihood for success of those reforms. Language in the Purpose of the Agreement, that the federal governments are to develop programs and practices for a better understanding of the Great Lakes, I interpret as inviting even demanding-the ongoing and rigorous pursuit of new knowledge and improved processes in Great Lakes governance to further place-based and regional restoration. Policy implementation deficits identified included a lack of understanding of cause and effect, inadequate communication and coordination, lack of time and resources for full implementation, and lack of agreement on objectives. Pathologies of management included a lack of responsiveness, a lack of institutional analysis and program evaluation, a resistance to new information and ideas, a lack of appropriate personalities in key roles, and multiple and incompatible programming. Policy tools for improved human-environment and science-policy linkages were examined as potential governance mechanisms to counter deficits and pathologies. Design principals of adaptive management and decision analysis were specified. These tools were placed within the policy and research context of the Great Lakes regime and linked to improved forms of accountability. A three-round online Policy Delphi study involved several dozen experts in the development and implementation of RAPs across the Great Lakes basin within government, industry, academia, and civil society. The research collected and aggregated (1) direct knowledge of the strengths and limitations of RAPs, which lead to (2) further knowledge of what worked and what did not work in the RAP program, which in turn facilitated (3) the emergence of seven governance options to improve institutional processes in RAP programming. Importantly, the results establish that both the structure and attributes of governance were significant to RAP outcomes. Ran kings of these options indicated a general consensus that the options were relatively feasible and likely to succeed as enhancements in the development and implementation of RAPs. The results indicate a need to focus significantly on the predominant tendencies and characteristic attitudes that underlie RAP processes. These findings will have broad significance for other evolving place-based nearshore restoration strategies in the Great Lakes and anywhere else such programs are initiated. The thesis culminates with a conceptual framework for adaptive governance, problem solving, decision making, and management. The framework encompasses three domains that correspond to established levels of institutional analysis: constitutional choice (political and societal processes), collective choice (policy and decision processes), and operational choice (resource use and management processes). Flows of information between domains can be facilitated or restricted depending on the rules and conventions of the institutional design. Traditional governance characteristically permits only a linear and downward flow of information that negates the possibility for double-loop learning by disallowing required feedbacks. Adaptive governance regimes intentionally encourage a return or upward (and outward) flow of information and promotes learning. The three domains in the framework are nested to indicate that the 'problem domain' is the entire social system, that problems of environmental governance cannot be restricted to subsets of issues, and that adaptive problem solving is multi-scalar. The framework explicitly links processes across domains and is adaptive because it bridges boundaries that traditionally separate society from policy decisions and isolate policy decisions from management activity. The Discussion underscores that learning is a key function of adaptive governance, and that it is operationalized through social capital, networks, leadership, and trust. The thesis recommends that the federal governments issue a reference to the International Joint Commission to establish an Adaptive Governance Task Force in order to provide a strong and independent forum to engage with the conceptual framework presented in this thesis and generally to discover adequate and appropriate strategies and opportunities for adaptive Great Lakes governance. / Thesis / Doctor of Philosophy (PhD)

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This dissertation is comprised of three essays examining methods for surface water quality valuation. The first essay uses Zillow's ZTRAX property transaction database to investigate variation in hedonic price effects of water clarity on single-family houses throughout the United States. I consider five spatial scales and estimate models using different sample selection criteria and model specifications. The results indicate considerable spatial heterogeneity both within and across the four U.S. Census regions. However, I also find heterogeneity resulting from different types of investigator decisions, including sample selection and modelling choices. Thus, it is necessary to use practical knowledge to consider the limits of market areas and to investigate the robustness of estimation results to investigator choices. In the second essay, I integrate a coastal recreation demand model for Southern New England with property sales in Massachusetts and Rhode Island to estimate the impacts of water quality improvements for freshwater and saltwater resources throughout the region. While traditional hedonic studies for water quality reveal the direct effects of local water quality on housing prices, the spatial extent of the models is limited to 2 km from the waterfront. Integrating recreation demand models with hedonic models allows identification of additional indirect effects of water quality at recreation sites that are capitalized in housing markets through a recreational index (i.e., the potential recreational benefits for a neighborhood). However, the spatial extent of these models is currently untested. I compare the spatial extent of indirect and direct effects of water quality for multiple water quality inputs isolating spatial and temporal sources of variation. The results indicate heterogeneity in the direct effects of freshwater and saltwater clarity depending on whether the source of variation is spatial or temporal. Conflating spatial and temporal water quality variation can lead to anomalous conclusions on the impacts of coastal recreation on housing markets. In the third essay, I evaluate meta-regression models (MRMs) that are used by policy makers in calculating the potential benefits of improvements in environmental quality resulting from proposed regulatory actions. MRMs lay the foundation for benefit transfers applied by EPA to recent rulemakings under the Clean Water Act (CWA) in addition to other environmental contexts (e.g., health benefits under the Clean Air Act). While recent literature has emphasized the necessity that MRMs satisfy key theoretical conditions, including scope sensitivity and the adding up condition, existing MRMs that fulfil these properties require imposing structural model restrictions or removing relevant explanatory variables from the MRM at the expense of model fit and predictive performance. This study presents a method for defining MRMs that draws on characteristics of the given benefits transfer scenario and its relationship to the metadata while satisfying the adding up condition. This modelling framework outperforms the model used by EPA in model fit and predictive performance. Applying the results to a recent CWA rule, I find the model used by EPA substantially underestimates the potential benefits. / Doctor of Philosophy / This dissertation is comprised of three essays examining methods for surface water quality valuation. The first essay uses property sale models to evaluate spatial differences in the impacts of lake water quality on housing markets throughout the United States. I evaluate how investigator decisions related to spatial scale of the model, sample selection criteria, and model specification effects the observed results. I find variation in the impacts of water on property sale prices across the nation. However, the results in some regions are highly sensitive to investigator decisions, implying limitations to using a single model to represent the impacts. The second essay integrates a property sale model for water quality with a model that examines willingness to pay for coastal recreation in Southern New England. I evaluate the impacts of water quality at coastal recreation sites on property sales in Massachusetts and Rhode Island and compare the results to the impacts of local water quality. I find the effects of local water quality is largest on the coast but only capitalized into property sales up to 2 km from the waterfront. I do not find expected results for coastal recreation. The third essay evaluates the models used by policy makers to calculate the potential benefits of improvements in water quality resulting from regulatory action. Previous models prioritized theoretical properties of models, such as the adding up condition, at the expense of model fit and predictive performance. I develop a hybrid model approach that can be used model water quality benefits while satisfying the adding up condition with improved model performance. I apply the model to a recently proposed rulemaking and find the benefits potential benefits greatly exceed those presented in the rule making.

Anthropogenic freshwater salinization, which is caused by numerous human activities including agriculture, urbanization, and deicing, impacts an estimated 37% of the contiguous drainage area in the United States. High salt concentrations in brackish and marine environments (~1,500 – 60,000 µS cm-1) influence aquatic bacteria. Less is known about the effects of freshwater salt concentrations (≤ 1,500 µS cm-1) on bacterial ecology, despite the pervasiveness of freshwater salinization. Bacteria perform many fundamental ecosystem processes (e.g. biogeochemical cycling) and serve as indicators of human health risk from exposure to waterborne pathogens. Thus, to understand how salt pollution affects freshwater ecosystems, there is a critical need to understand how freshwater salinization is impacting bacterial ecology. Using a series of controlled mesocosm experiments, my objectives were to determine how (1) survival of fecal indicator bacteria (FIB), (2) the diversity of native freshwater bacterial communities, and (3) bacterial respiration and nutrient uptake rates responded across a freshwater salinity gradient of different salt profiles. Survival rates (t90) of Escherichia coli, the EPA recommended freshwater FIB, increased by over 200% as salinity increased from 30 to 1,500 µS cm-1. Survival rates were also significantly higher in water with elevated Mg2+ relative to other base cations, suggesting that different salt sources and ion profiles can have varied effects in FIB survival. Thus, freshwater salinization could cause accumulating concentrations of FIB even without increased loading, increasing the risk of bacterial impairment. Diversity of native bacterial communities also varied across a freshwater salinity gradient, with a general increase in species richness as salinity reached 1,500 µS cm-1. Community variability (β-diversity) was greatest at intermediate salinities of 125 – 350 µS cm-1 and decreased towards the upper and lower extremes (30 and 1,500 µS cm-1, respectively). These diversity patterns suggest that osmotic stress is an environmental filter, but filtering strength is lowest at intermediate salinities causing a change from more deterministic to more stochastic assembly mechanisms. Different salt types also produced distinct bacterial community structures. Lastly, bacterial respiration doubled as salinity increased to 350 – 800 µS cm-1, revealing a subsidy-stress response of bacterial respiration across a freshwater salinity gradient. Corresponding changes in nitrogen and phosphorus uptake increased N:P ratios in ambient water, especially in mesocosms with elevated Ca2+, which could affect nutrient limitation in salinized streams enriched with Ca2+. Bacterial community structure based on Bray-Curtis dissimilarity was not correlated to pairwise changes in respiration rates but was linked to net nitrogen and phosphorus uptake after five days. Collectively, these results establish that freshwater salinization alters bacterial ecology at the individual population, whole community, and ecosystem process scales. Further, different salt types (e.g., CaCl2, MgCl2, NaCl, KCl, sea salt) had varying effects on bacteria at all levels and should be considered when predicting the effects of salinization on freshwater ecosystems. Developing more nuanced salt management plans that consider not only amount, but different types, of salts in freshwaters could help improve our ability to predict human health risk from waterborne pathogens and mitigate/ reduce salinity-induced impacts to freshwater ecosystem processes and services. / Doctor of Philosophy / Humans rely on streams, rivers, and lakes for many services including transportation, recreation, food, and clean drinking water. Despite our reliance on freshwater ecosystems, human activity has significantly degraded freshwater resources worldwide. Recently, salt pollution caused by human activity on land, known as freshwater salinization, has emerged as a widespread water quality issue. Numerous human activities including agriculture, urbanization, resource extraction, and deicing have increased freshwater salt concentrations in 37% of the United States' contiguous drainage area. Large changes in salinity (i.e. from freshwater to oceanic salinities) are known to affect bacteria that perform many important ecological functions, such as nutrient cycling and water purification, while the effects of smaller changes in salinity more typical within the freshwater range are unknown. I used controlled laboratory experiments to determine how freshwater salinization affects (1) survival rates of Escherichia coli, (2) diversity of native bacterial communities, and (3) bacterial nutrient cycling. My results revealed that freshwater salinization can significantly increase how long E. coli survive in freshwater. E. coli are used to detect the presence of waterborne pathogens and reduce human health risk. Thus, freshwater salinization might reduce the reliability of E. coli as an indicator of waterborne pathogens as well as increase concentrations of bacterial that are potentially harmful to human health in freshwater. Additionally, freshwater salinization affected bacterial diversity by altering the ways in which bacterial communities form. In general, the number of bacterial species present increased as salinity reached the upper freshwater limit, but communities were most variable at intermediate freshwater salt concentrations. These diversity patterns suggest that different salt concentrations can either cause or reduce stress in bacteria, resulting in significantly different bacterial communities. Lastly, moderate increases in freshwater salt concentrations doubled bacterial respiration and nutrient uptake rates. Bacterial respiration influences how energy flows through ecosystems, and freshwater salinization could potentially alter this process. Different salt types also had different effects of bacterial ecology. Collectively, my results establish that freshwater salinization impacts bacteria at the individual, community, and ecosystem levels.

Antibiotic resistance (AR) is widely associated with intensive agricultural systems, pharmaceutical production, wastewater, and health facilities. However, little research has been conducted on AR gene (ARG) dynamics in natural environments lacking large-scale human inputs. In particular, we have a limited understanding of the complex dynamics influencing environmental AR in resource-limited dryland systems threatened by climate change. In northern Botswana, Escherichia coli isolates were obtained from river surface water (n = 426 samples; September 2017 – May 2018), sediments (n = 194; November 2017 – May 2018), and human fecal samples (n = 43 September 2017 and April 2018). A multiplex PCR assay was used to assess gene frequencies for sulfonamide (sul1 and sul2), tetracycline (tetA and tetB), and class 1 integron (intl1) resistance genes. The weighted frequency of sul1 in sediment E. coli isolates (µ= 0.07; SD = 0.39) was significantly higher than that observed in isolates obtained from surface water (µ= 0.03; SD = 0.15; p = 0.01). Weighted gene frequencies for sul1 and sul2 in human E. coli isolates from April 2018 were significantly higher than those in water (sul1 p = 0.01; sul2 p = 0.00) and sediment isolates (sul1 p = 0.01; sul2 p = 0.00) from the same time period. Significant differences for the five genes' weighted frequencies were observed between sampling months in water isolates (intl1 p = 3.318e-05; sul1 p = 3.217e-06; sul2 p = 4.392e-06; and tetA p = 2.477e-05), while only intl1 frequency differed significantly between months in sediment isolates (p = 0.05). While no significant spatial patterns of ARG frequencies were observed in E. coli isolates from water samples (p = 0.16), higher ARGs were observed in E. coli isolated from human-dominated land areas for intl1 (µ = 0.10; SD = 0.31) than in protected landscapes intl1 (µ = 0.03; SD = 0.13; p = 0.02). Land use also was associated with higher weighted frequencies for tetA in E. coli isolates from water in human-dominated land areas (µ = 0.10; SD = 0.30) compared to protected areas (µ = 0.04; SD = 0.23, p = 0.03). These results indicate that the interactions between land use and season-dependent hydrometeorological factors drive frequencies of some ARGs across this system, but do not fully explain the complexities observed. However, the lack of higher weighted gene frequencies for riverbed sediments suggests that they do not act as a reservoir for ARGs in the system, implicating humans as significant contributors to ARG persistence in the aquatic system. / Master of Science / Microbial antibiotic resistance (AR) is widespread and an increasingly important public and animal health threat, especially in developing nations. Our understanding of the influence of environmental factors, such as seasonality and river flow characteristics, and landscape features on AR distributions is limited. For this project, I analyzed the presence of genes associated with resistance to five different types of antibiotics, called antibiotic resistance genes (ARGs), in Escherichia coli isolates obtained from Chobe River surface water and sediment samples across varying land uses (park, town, and mixed) and from feces of humans living in the region. The differences in land use are such that the park acts as a protected management area for a large variety of wildlife species with little human development and is therefore 'pristine', while the town and mixed land uses have varying degrees of human modification. Land use and month were both significantly associated with differences in AR gene frequencies in isolates from both water and sediment samples. For some genes, most detections were in sediment isolates and only infrequently in water isolates. However, with the onset of the rainy season, frequencies of some genes were higher in water isolates than in sediment isolates, indicating the role of rainfall and river flow dynamics in ARG dissemination. As was expected, AR genes were more frequently detected in human fecal sample isolates than in water and sediment isolates, which was consistent with views that humans are the primary source of environmental ARG contaminants. I discuss these results and explore the implications to management of antibiotic resistance across the human-environmental interface.

Surface application of broiler litter to grasslands can increase concentrations of ammonium (NH₄+-N) and dissolved reactive phosphorus (DRP) in surface runoff. It is not known, however, for how long after broiler litter applications that NH₄+-N and DRP concentrations remain elevated. Five 0.75-ha, fescue-bermudagrass paddlocks received four broiler litter applications in 1995 and 1996, and only inorganic fertilizer N in 1997 and 1998. Runoff from each paddock was measured, sampled, and analyzed for NH₄+-N and DRP. Flow-weighted NH₄+-N and DRP concentrations increased from background values of 0.5 and 0.4 mg L-1, respectively, to values as high as 50.7 mg NH₄+-N L⁻¹ and 18.8 mg DRP L-1 in a runoff event that occurred immediately after the third litter application. Concentrations remained high while broiler litter was being applied but decreased steadily after the last application, reaching values near 1 mg L⁻¹ (for NH₄+-N and DRP) by 19 months after the final application. Among the factors that affected the average concentration of NH₄+-N and DRP in cumulative runoff after a litter application were cumulative runoff, rates of total N and NH₄+-N applied, and cumulative total litter N, total litter P, and water-soluble litter P applied during the four years of the study. Soil test P also affected DRP concentrations, but its effect depended on when the paddocks last received broiler litter. There is a need for tools to identify situations in which the application of broiler litter may enrich surface runoff with P. One such tool is the simulation model Erosion Productivity Impact Calculator (EPIC). EPIC's ability to simulate runoff volume and losses of dissolved reactive P (DRP) was evaluated. Data from the five 0.75-ha, tall fescue-bermudagrass plots that were fertilized with broiler litter during two years, and received only inorganic fertilizer N for the two subsequent years, were compared with EPIC estimates. EPIC simulations of runoff volume in individual events did not show bias in three of the plots but underestimated runoff in one plot and overestimated runoff in another. On an annual basis, the runoff volumes simulated by EPIC were similar to the observed values. A modified version of EPIC yielded better estimates of event DRP losses than the original EPIC and generated estimates of annual DRP loss that were similar to observed values. These results suggest that the modified EPIC may be useful for identifying situations where there is a high risk of large annual P losses from grasslands fertilized with broiler litter. / Ph. D.

Crop production, soil system, water quality, and economic impacts of four corn silage production systems were compared through a field study including 16 plots (4 replications of each treatment). Systems included a rye cover crop and application of liquid dairy manure in the spring and fall. The four management systems were: 1) traditional, 2) double-crop, 3) roll-down, and 4) undercut. In the fourth system, manure was applied below the soil surface during the undercutting process. In all other systems, manure was surface-applied. In the third system, the rye crop was flattened with a heavy roller after manure application. Simulated rainfall was applied within 48 h of manure application. Measured constituent concentrations in runoff were compared with water quality criteria. Costs and returns of all systems were compared. The undercut system reduced loadings of all nutrients, but increased total suspended solids (TSS) concentration as compared with all other systems. The mean volume of runoff from the undercut system was less than half that from any other system, which influenced all constituent loadings. Mean TSS concentration in runoff from the undercut system was over three times the mean of any other system. The roll-down system had no significant effect on water quality as compared to the traditional system. The undercut system was reasonably effective in keeping phosphate phosphorus levels below the criterion set for bathing water. None of the systems generally exceeded nitrate nitrogen concentration criteria. However, total phosphorus, orthophosphate, fecal coliform and e. coli criteria for drinking, bathing, shellfish harvest, and aesthetics were regularly exceeded by all of the systems. There were no differences among the treatments in effects on bacterial concentrations. The double-crop system produced significantly higher net returns than all other systems only if the value of the rye crop was $92.31/Mg or more. There were no significant differences in net returns of the traditional, roll-down, or undercut systems. / Ph. D.

Stormwater management in urban areas is a major concern today. The problem of disposing of this stormwater runoff in a satisfactory manner is very difficult indeed. Both the quantity and quality aspects of the runoff must be dealt with to obtain a solution of this problem. The water quality of the runoff can vary depending upon the different land uses of the drainage basin. The quantity of the stormwater runoff also depends upon the land uses, the rainfall intensity and duration of the storm. The traditional methods available for determining the quantity of the stormwater runoff are numerous. These traditional methods and recently developed mathematical simulation models are discussed in this paper. Prediction of the water quality of stormwater runoff is in its infancy. Several of the mathematical models have the capabilities of quality simulation, however, the simulation results are usually inconsistent with actual quality data. Of the simulation models currently in use, the EPA Storm Water Management Model is one of the most comprehensive models. Application and verification of these newly developed models is limited. The EPA Model was chosen to simulate the quantity and quality of a small urban drainage area. The study area chosen was an urban commercial section of the Lake Eola drainage basin. Physical data of the study area, such as ground slopes, storm sewer sizes and locations and slopes were determined. This data was then utilized for simulations of actual rainfall events. Verification of the quantity and quality simulation results was performed with actual quantity and quality data obtained for these rainfall events. Quantity simulation was considered successful with good correlation between the simulated and actual runoff. Quality simulation was successful to a lesser degree, the conclusion being that further quality calibration of the Model was required. Correlation between actual and simulated stormwater quality was achieved to some extent. The lack of correlation was felt to be due to calibration of the Model.

The purpose of this study was to evaluate the performance of alum alone, alum in conjunction with a polymeric coagulant aid, and a primary coagulant polymer in the coagulation-flocculation-sedimentation portion of a water treatment process and to study the implications of the results with respect to future use in direct filtration. The performance of the coagulant, coagulant aid, and primary coagulant polymer was evaluated by altering the flocculation and sedimentation retention times in the pretreatIDEnt process chain. Among the water quality parameters monitored were turbidity, pH, total alkalinity, total hardness, and total solids. A brief literature review for direct filtration and coagulation-flocculation theory was also conducted. The results of this investigation indicated that reduced retention times in the pretreatment process chain treated the selected raw waters sufficiently to enable consideration of direct filtration a viable treatment alternative. Analysis of data obtained indicated the use of polyelectrolyte as a primary coagulant or coagulant aid produced a pinpoint floc which is essential to successful utilization of direct filtration and that the floc formed settled more rapidly than floc from use of aluminum sulfate alone. The use of a polyelectrolyte as a primary coagulant or coagulant aid also reduced the chemical dosages required to provide appropriate turbidity removals. / Master of Science