Heat-as-a-tracer has become a common method to quantify surface water-groundwater interactions (SW/GW). However, the method relies on a number of assumptions that are likely violated in natural systems. Numerical studies have explored the effects of violating these fundamental assumptions to various degrees, such as heterogeneous streambed properties, two-dimensional groundwater flow fields and uncertainty in thermal parameters for the 1-dimensional heat-as-a-tracer method. No work to date has addressed the impacts of non-uniform, three-dimensional groundwater flows on the use of heat-as-a-tracer to quantify SW/GW interactions. Synthetic temperature time series were generated using COMSOL Multiphysics for a three-dimensional cube designed to represent a laboratory setup of homogeneous, isotropic sand with a sinusoidal temperature variation applied to the top. We compare temperature-derived fluxes to model-generated fluxes to assess the performance of methods using temperature to quantify 1D vertical fluxes in response to multi-dimensional groundwater flows. Both increasingly non-uniform and non-vertical groundwater flow fields result in increasing errors for both amplitude-ratio-derived groundwater flux and temperature-derived effective thermal diffusivity. For losing flow geometries, errors in temperature-derived effective thermal diffusivity are highly correlated with errors in temperature-derived flux and can be used to identify if underlying assumptions necessary for heat-as-a-tracer for quantifying groundwater flows have been violated. For this model set-up, when groundwater flows are non-uniform, the thermal method generally calculates fluxes outside the range occurring between temperature sensor pairs. When errors are low (15% of flux calculations), temperature derived fluxes more closely match the minimum magnitude flow occurring between the sensors.

Water management techniques in the Southern Maya Lowlands are both regionally diverse and site specific. This thesis examines the water management strategies of the Classic Period Maya at the site of Caracol, Belize. While it is likely that elites at Caracol controlled the redistribution of resources, i.e. craft and agricultural products, it is probable that the production of agricultural resources and the maintenance of water resource acquisition took place on a more local level. In order to test this hypothesis, a sample of five reservoirs were examined through original research -- and situated in conjunction with past settlement studies -- to determine the water storage capacity and likely function of different water management features throughout the built environment of Caracol. As a result, this thesis argues that the placement and construction of water management features -- i.e., reservoirs -- at the site of Caracol, Belize are indicative of specific landscape patterns which are expressed by a distinct vernacular construction style and are also a reflection of the socio-political organization present within the site during the Late Classic Period.

Water is a fundamental human right supporting life, health, and livelihoods. Yet water-related issues are ranked among the top five global economic risks (WEF, 2020). About two-thirds (4 billion) of the world's population live with severe water scarcity for at least one month, of which about 48% live in both India and China (Mekonnen et al., 2016). In Côte d'Ivoire, the Bandama River, one of the largest in the country, has struggled to meet expected demand, causing recurrent water and electricity shortages. The city of Bouaké in Côte d'Ivoire and neighboring towns experienced a severe water shortage in 2018 with the drying up of the water supply reservoir (Loka along the Bandama River), affecting 70% of the population causing difficult economic and social conditions. To fully understand this dimension of water scarcity in the Bandama watershed, this study models current water availability using SWAT and assesses the current watershed system in Cote d’Ivoire. Model calibration and validation performances were suboptimal. However, the model gave important information about the dominant process and the critical areas of the watershed. This information guided the development of strategies to build resilience in the water supply system through institutional and stakeholder-driven approaches.

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Finding solutions to treat water that contains phosphorus is an important effort due to the harmful impacts it presents to both human health and the environment. Phosphorus is considered a limiting factor in water oftentimes and therefore controls the growth of algal bloom in a water body. The increase of algal populations due to wastewater effluent, stormwater runoff, and agricultural discharge in Florida waters has a direct link to the event of harmful algal blooms such as red tide in coastal regions, eutrophication of waterbodies, and fish kills. Finding low cost, energy efficient, and low maintenance green sorption media (GSM) solutions to treat this nutrient laden water is the main focus of this study. Phosphorus removal efficiencies were studied in the lab using two new recipes of GSM with a unique passive energy cascade upflow hydraulic pattern. The study goal involves comparing the two new GSM in terms of their removal rates of phosphate, removal mechanisms, and their differential effects via a lab-scale cascade upflow filtration system. The two new GSM include Zero-valent Iron and Perlite Green Environmental Media (ZIPGEM) composed of 85% sand, 5% clay, 5% zero valent iron, 5% perlite by volume, and Biochar zero-valent Iron and Perlite Green Environmental Media (BIPGEM) containing 80% sand, 5% biochar, 5% clay, 5% perlite, 5% zero valent iron by volume. To explore the differential effects, the addition of biochar in BIPGEM is of special interest in this study and expected to perform better than its counterpart ZIPGEM. However, results indicated that ZIPGEM, when treated as a system, experienced an average percent removal of 97.9% to 78.9% from the initial 60 minute to 300 minute range, whereas BIPGEM experienced an average 86.9% to 67.1% removal during this same time interval. At the time of shutdown for the BIPGEM runs (5,480 minutes), BIPGEM as a system possessed an average 52.8%, and ZIPGEM a 69.1% removal. Upon shutdown for ZIPGEM at the 11,180 minutes mark, ZIPGEM was still at an average 69.1% removal. Further comparison of the material structures and compositions of two GSM involve chemical composition analysis of both raw and spent media samples using X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), and scanning electron microscope (SEM) in the Advanced Materials Processing and Analysis Center (AMPAC) at the University of Central Florida (UCF). Two experimental runs with slightly different flow rates were conducted for each type of sorption medium to explore the process reliability of such a cascade upflow filtration system. Statistical analysis via the Kolmogorov-Smirnov Test was calculated to compare goodness of fit between the two sets of performance curves associated with each sorption media and experimental run in the lab. The results of this study show that the inclusion of biochar did not support the hypothesis that BIPGEM would perform better than ZIPGEM in phosphorus removal and the two experimental runs are statistically similar. This may be due to the quantity of biochar not being enough to provide significant adsorption of phosphorus or the possibility of synergistic effects between the other ingredients within the recipe altering the physical or chemical adsorption properties expected from the medium. It is recommended that further studies in a downflow filtration system (i.e., a column study) take place to continue the understanding of the impact associated with changing hydraulic pattern and higher content of biochar in the recipe based on this study.

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No description available.

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Cryptosporidium parvum is a common surface water contaminant that can cause illness in human beings. The presence of this etiological agent in groundwater identifies the groundwater as under the direct influence (GWUDI) of surface water. Currently the determination of GWUDI water sources requires an expensive, labor-intensive laboratory procedure called the Microscopic Particulate Analysis (MPA). The results of the MPA provide a risk index that rates the degree of surface water contamination. The objective of this study is to identify other methods of identifying GWUDI of surface waters, such as well characteristics and hydrogeologic factors which may contribute to higher MPA risk indices. In order to determine which public water systems that are GWUDI, a total of sixty-two wells at water treatment systems suspected of being GWUDI were investigated. The wells sampled were distributed across seven counties in the Central Florida region. Water samples were collected and analyzed at the Department of Health Laboratory in Tampa, Florida using the MPA. The study also investigated the well characteristics and the hydrogeology of the well locations.