Root, Tara L.

Arsenic is a known carcinogen, but is persistent in the environment, remaining a popular pesticide. It represents a particular hazard to humans when it stays resident in shallow soils and groundwater. This study of contaminant hydrogeology examined conditions at a former golf course in Florida with known arsenic contamination, and included a detailed examination of existing assessment data for the study area, an experimental pumping test with groundwater sampling, examination of sediment cores, and a preliminary geophysical investigation. The primary purpose was to determine what the existing controls are on As mobility. The primary findings were that redox conditions did have an effect on As concentrations. Groundwater in the study area is generally reducing, but during the pumping test was generally oxidizing. No potential As sources were definitively identified, and the most likely source remains anthropogenic, but interactive conditions with Fe, Mn, NO3-N, and S remain nebulous.

Water treatment facilities across the United States are known for providing high-quality drinking water to their residents. However, differences in treatment methods, aging infrastructure, and outdated household plumbing may affect the quality of drinking water by the time it reaches the consumer’s tap. Palm Beach County, Florida, is an area with large socioeconomic contrasts where some families live in dilapidated structures and others reside in luxurious, gated communities. This research highlights the variation of household water quality by determining metal concentrations in tap water samples in communities of different socioeconomic status. In addition, interviews were conducted with personnel from five different Water Treatment Plants (WTPs) in the study area to understand the relationship between customers and their water utility. Results indicate that effective communication strategies are needed to boost public trust and fill critical information gaps about the water treatment process. Ninety-six tap water samples were collected from households throughout eastern Palm Beach County and analyzed for different metals using Inductively Coupled Plasma Optical Emission Spectrometry. Surveys were also administered at the same households where tap water samples were collected. Residents were asked about their perceptions of tap water and social and economic questions regarding their household characteristics. A Socioeconomic Status (SES) index was created using Principal Components Analysis (PCA) to understand how perceptions of tap water quality and concentrations of metals in household tap water vary based on SES. Results provide evidence that those living in the lowest-ranking SES neighborhoods are the least satisfied with their tap water quality and consume less tap water than those living in higher SES neighborhoods. Water quality results highlighted large variations in concentrations of aluminum (Al) and thus, analyses focused specifically on how Al concentrations varied according to SES. Results from Ordinary Least Squares regression show that as socioeconomic status decreases, the concentration of Al in tap water increases. Six samples exceed the State of Florida’s Secondary Maximum Contaminant Level (SMCL) for Al, and five of those samples were found in the lowest-ranking SES neighborhoods (SES 1 and 2). The results of this research provide evidence that inequities in household water quality exist across eastern Palm Beach County, Florida.

Trinidad is highly dependent on surface water as a source for domestic
water supply. Due to lack of infrastructure some areas have limited access to
potable/reliable source of water. Increases in industrialization and population
are putting more pressure on water resources, exacerbating the problem. Part of
this study looks at how, and from where people in different geographic regions
in northern Trinidad collect and store water. Results indicate that urban areas
rely on public water as a water source. The urban fringe relies on a public water
supply as well as self-supplied sources. Rural regions depend solely on a selfsupply
source. Also, I look at how nitrate and nitrite concentrations in drinking
water vary with geographic location. Results indicate water quality varies with
source and collection method. Further research is needed to confirm this.

This thesis evaluates the water chemistry and hydrology of an urban
environmental preserve in advance of wetland construction. Pondhawk Natural Area
(PNA) is located in densely populated Palm Beach County, Florida and was acquired
through the County's Environmentally Sensitive Lands Acquisition Program as a
protected natural area. In an effort to restore the natural area to pre-development
conditions Palm Beach County will construct a wetland in the area where hydric
conditions persisted prior to the extensive canal construction that lowered groundwater
levels. Results of this study wi II provide initial characterization of hydrology and water
quality of PNA before wetland construction and lay the groundwork for future
monitoring and improvements.

Evaluating trends of historical rainfall on a weekly and seasonal basis is needed
for optimizing the design and implementation of lawn water conservation strategies like
outdoor water restrictions. While “day of the week” water restrictions are a typical
strategy to limit the frequency and duration of urban lawn water use, they may not
necessarily result in more conservative behaviors from end-users. Because weekly
rainfall and local climate variables are seldom taken into account in water restriction
strategies, they are not connected to actual lawn water demand. However, since lawn
water demand is directly related to weekly rainfall totals, not to a particular number of
watering days per week, water restriction schedules have the potential to unintentionally
promote overwatering. This study investigated the weekly patterns of average seasonal rainfall and evapotranspiration in South Florida to determine the typical variability of
weekly net irrigation needs and found that typical wet season weekly rainfall often
provides a significant amount of water to meet the demand of residential lawns and
landscapes. This finding underscores opportunity to reduce supplemental overwatering
in residential landscapes if watering guidelines were modified to recognize seasonal
average weekly rainfall in this region
This study also tested a rainfall-based water conservation strategy to determine if
providing residents with information about how local rainfall could promote more
effective lawn watering behavior than just water restrictions alone. Experimental
households reduced lawn water use by up to 61% compared to the control group by the
end of the study. These results demonstrate that the neighborhood “rain-watered lawn”
signs helped experimental study group households become more aware of rainfall as the
primary input of water to their lawns. This study also investigated the role that lawn
irrigation from self-supplied sources plays in the urban lawn water demand and
investigates how the lawn water use and lawn watering behaviors of households that
source from self-supply differ from those who source from the public supply.

In recent decades, ecohydrology has received renewed attention because of the impacts of groundwater withdrawal on ecosystems. Growing population and urban expansion in Palm Beach County, FL. place pressure to eradicate natural areas, such as Florida scrub habitats, and increase groundwater withdrawal. This study presents preliminary results of soil and hydrological characterization of an ecological preserve surrounded by changing land use. Soil moisture and water levels were monitored to assess the effects of precipitation as influenced by plants and soil analysis determined the suitability of current soil conditions for hosting native vegetation habitats. Hydrologic and soil conditions on the preserve fall within values expected for native Florida scrub habitats. Hydrologic response to precipitation varied due to factors including antecedent conditions and vegetation types. These results provide a better understanding of the interactions between soil proper ties, hydrologic cycle, and plants, and assist with establishing a baseline to monitor changes over time.

In southeastern Florida, the majority of drinking water comes from the Biscayne aquifer. This aquifer is comprised of heterogeneous limestones, sandstones, sand, shell and clayey sand with zones of very high permeability. Visualizing the spatial variations in lithology, porosity and permeability of heterogeneous aquifers, like the Biscayne, can be difficult using traditional methods of investigation. Using the Roxar IRAP RMS software multi-layered 3D conceptual geomodels of the lithology, cyclostratigraphy and porosity were created in a portion of the Biscayne aquifer. The models were built using published data from borehole geophysical
measurements, core samples, and thin sections. Spatial relations between lithology,
cyclostratigraphy, porosity, and preferential flow zones were compared and contrasted to
better understand how these geologic features were inter-related. The models show local areas of differing porosity within and cross-cutting different cycles and lithologies. Porosity in the Biscayne aquifer study area follows a hierarchy attributed to lithofacies with a pattern of increasing porosity for the high frequency cycles. This modeling improves understanding of the distribution and interconnectedness of preferential flow zones, and is thus an invaluable tool for future studies of groundwater flow and groundwater contamination in the Biscayne aquifer.