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Research about Palm Beach County, Florida

Source-linked reports with geographic coverage including Palm Beach County, Florida.

At least 19 recordsLinked to original sources
USGS2023

Accuracy and precision of sea-finding orientation as a function of dune proximity in hatchlings of two species of sea turtles

Context: Sea turtle hatchlings generally emerge at night from nests on sand beaches and immediately orient using visual cues, which are believed to entail the difference in brightness between the light seen in the seaward direction and that seen in the duneward direction. Aim: The aim of this study was to understand how dune proximity affected hatchling orientations in two sea turtle species that share a nesting beach 15 km long and 25.3 ± 9.4 m ( N = 215) from dune to waterline, with low to moderate artificial light nearby. Methods: For hatchling loggerhead and green turtles, we measured accuracy and precision of orientation, tested differences in distance from nest to dune, and investigated the effect of dune proximity on hatchling orientation. Key results: We found a significant decrease in hatchling orientation accuracy and precision in both species as the distance increased from nests to dune. Loggerhead and green turtles showed similar orientation ability when in the same proximity to the dune. Conclusions: We conclude that dune features provide important cues for hatchling orientation on sea turtle nesting beaches. Implications: Restoring and maintaining natural beach profiles, especially dune systems, is likely to increase the accuracy and precision of sea finding in hatchling sea turtles.

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USGS2000

Patterns of change in tree islands in Arthur R. Marshall Loxahatchee National Wildlife Refuge from 1950 to 1991

Size, shape, orientation, and distribution of tree islands in a remnant of northern Everglades wetland were examined from 1950 and 1991 aerial photography. The objectives were to quantify the patterns of tree islands in Loxahatchee National Wildlife Refuge, to determine if the patterns of tree islands had changed between the two dates, and to relate the tree island patterns to modeled pre- and post-drainage hydrologic patterns. There was considerable variation in the patterns of tree islands spatially and temporally. Changes in the size and shape of tree islands from 1950 to 1991 are consistent with changes in the modeled pre- and post-drainage hydrologic patterns. Photo plots along the edges of the refuge, where hydroperiods are longer and depths deeper than they were historically, show a decrease in tree island size and in overall area of tree islands in the plots. Photo plots in the interior, where hydroperiods are shorter than they were pre-drainage, show an increase in tree island area. Overall, there is a tendency for more tree islands to be irregularly shaped in the 1991 photo plots than in the 1950 plots, a reflection of the loss of water flow, reduction of pulse magnitude, and the ponding of water along the perimeter dikes. This study illustrates the importance of considering long-term changes in hydroperiod, depths, and water flows in the restoration of this area.

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USGS2000

Hydrogeology and the distribution of salinity in the Floridan aquifer system, Palm Beach County, Florida

The virtually untapped Floridan aquifer system is considered to be a supplemental source of water for public use in the highly populated coastal area of Palm Beach County. A recent study was conducted to delineate the distribution of salinity in relation to the local hydrogeology and assess the potential processes that might control (or have affected) the distribution of salinity in the Floridan aquifer system. The Floridan aquifer system in the study area consists of the Upper Floridan aquifer, middle confining unit, and Lower Floridan aquifer and ranges in age from Paleocene to Oligocene. Included at its top is part of a lowermost Hawthorn Group unit referred to as the basal Hawthorn unit. The thickness of this basal unit is variable, ranging from about 30 to 355 feet; areas where this unit is thick were paleotopographic lows during deposition of the unit. The uppermost permeable zones in the Upper Floridan aquifer occur in close association with an unconformity at the base of the Hawthorn Group; however, the highest of these zones can be up in the basal unit. A dolomite unit of Eocene age generally marks the top of the Lower Floridan aquifer, but the top of this dolomite unit has a considerable altitude range: from about 1,200 to 2,300 feet below sea level. Additionally, where the dolomite unit is thick, its top is high and the middle confining unit of the Floridan aquifer system, as normally defined, probably is not present. An upper zone of brackish water and a lower zone of water with salinity similar to that of seawater (saline-water zone) are present in the Floridan aquifer system. The brackish-water and saline-water zones are separated by a transition zone (typically 100 to 200 feet thick) in which salinity rapidly increases with depth. The transition zone was defined by using a salinity of 10,000 mg/L (milligrams per liter) of dissolved-solids concentration (about 5,240 mg/L of chloride concentration) at its top and 35,000 mg/L of dissolved-solids concentration (about 18,900 mg/L of chloride concentration) at its base. The base of the brackish-water zone and the top of the saline-water zone were approximately determined mostly by means of resistivity geophysical logs. The base of the brackish-water zone in the study area ranges from about 1,600 feet below sea level near the coast to almost 2,200 feet below sea level in extreme southwestern Palm Beach County. In an area that is peripheral to Lake Okeechobee, the boundary unexpectedly rises to perhaps as shallow as 1,800 feet below sea level. In an upper interval of the brackish-water zone within the Upper Floridan aquifer, chloride concentration of water ranges from 490 to 8,000 mg/L. Chloride concentration correlates with the altitude of the basal contact of the Hawthorn Group, with concentration increasing as the altitude of this contact decreases. Several areas of anomalous salinity where chloride concentration in this upper interval is greater than 3,000 mg/L occur near the coast. In most of these areas, salinity was found to decrease with depth from the upper interval to a lower interval within the brackish-water zone: a reversal of the normal salinity trend within the zone. These areas are also characterized by an anomalously low altitude of the base of the brackish-water zone, and a much greater thickness of the transition zone than normal. These anomalies could be the result of seawater preferentially invading zones of higher permeability in the Upper Floridan aquifer during Pleistocene high stands of sea level and incomplete flushing of this high salinity water by the present-day flow system.

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USGS1996

Assessment of water quality in the South Indian River Water Control District, Palm Beach County, Florida, 1989-94

The South Indian River Water Control District is located in an area of northern Palm Beach County, Fla., where many residents must rely on private wells for domestic water supplies and individual septic tanks for waste disposal. As a result, contamination of the surficial aquifer system and availability of a potable water supply have become of increasing concern. To address this concern, the U.S. Geological Survey, in cooperation with the South Indian River Water Control District, conducted a study to assess ground-water and surface-water quality in the District from 1989 to 1994. The study consisted of water-quality monitoring at 11 wells and 14 surface-water sites located within the District. Water samples were analyzed for major inorganic constituents and physical characteristics, trace metals, nitrogen and phosphorus species, and synthetic organic compounds. The predominant water type within the South Indian River Water Control District is calcium bicarbonate; however, mixed-ion type water and sodium bicarbonate type water also exist in varying amounts. Sodium chloride type water is present in the western areas of the District due to incompletely flushed residual sea water. Results of the study indicated that concentrations of most constituents were within State drinking-water standards as established by the Florida Department of Environmental Protection, but concentrations of certain constituents occasionally exceeded drinking-water standards in some ground-water and surface-water samples. Sodium and chloride concentrations exceeded the standards in ground water at two wells, dissolved-solids concentrations at five ground-water wells and one surface-water site, and color values at all 11 ground-water wells and all 14 surface-water sites. Other constituents also exhibited concentrations that exceeded drinking-water standards. Cadmium and zinc concentrations exceeded the standards in ground water at one well, and lead concentrations exceeded the standard in ground water at five wells. Nitrogen and phosphorus specie concentrations did not exceed respective drinking-water standards in any ground-water or surface-water samples. Additionally, organic compounds were not detected at four surface-water sites monitored for National Pollutant Discharge Elimination System constituents. Several synthetic organic compounds were detected at or above 50 micrograms per liter in water samples collected from six ground-water wells and three surface-water sites.

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USGS1993

Hydrogeology and simulation of ground-water flow near the Lantana Landfill, Palm Beach County, Florida

The Lantana landfill in Palm Beach County has a surface that is 40 to 50 feet above original ground level and consists of about 250 acres of compacted garbage and trash. Parts of the landfill are below the water table. Surface-resistivity measurements and water-quality analyses indicate that leachate-enriched ground water along the eastern perimeter of the landfill has moved about 500 feet eastward toward an adjacent lake. Concentrations of chloride and nutrients within the leachate-enriched ground water were greater than background concentrations. The surficial aquifer system in the area of the landfill consists primarily of sand of moderate permeability, from land surface to a depth of about 68 feet deep, and consists of sand interbedded with sandstone and limestone of high permeability from a depth of about 68 feet to a depth of 200 feet. The potentiometric surface in the landfill is higher than that in adjacent areas to the east, indicating ground-water movement from the landfill toward a lake to the east. Steady-state simulation of ground-water flow was made using a telescoping-grid technique where a model covering a large area is used to determine boundaries and fluxes for a finer scale model. A regional flow model encompassing a 500-square mile area in southeastern Palm Beach County was used to calculate ground-water fluxes in a 126.5-square mile subregional area. Boundary fluxes calculated by the subregional model were then used to calculate boundary fluxes for a local model of the 3.75-square mile area representing the Lantana landfill site and vicinity. Input data required for simulating ground-water flow in the study area were obtained from the regional flow models, thus, effectively coupling the models. Additional simulations were made using the local flow model to predict effects of possible remedial actions on the movement of solutes in the ground-water system. Possible remedial actions simulated included capping the landfill with an impermeable layer and pumping five leachate recovery wells. Results of the flow analysis indicate that the telescoping grid modeling approach can be used to simulate ground-water flow in small areas such as the Lantana landfill site and to simulate the effects of possible remedial actions. Water-quality data indicate the leachate-enriched ground water is divided vertically into two parts by a fine sand layer at about 40 to 50 feet below land surface. Data also indicate the extent of the leachate-enriched ground-water contamination and concentrations of constituents seem to be decreasing over time.

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USGS1988

Direct-current resistivity data from 94 sites in northeastern Palm Beach County, Florida

Direct-current resistivity data were collected from 94 vertical electric sounding profiles in northeastern Palm Beach County, Florida. Direct-current resistivity data, which may be used to determine the location and thicknesses of shallow, semipermeable marls or locate zones of high chloride concentration, are presented in this report. The resistivity data consist of field data, smoothed data, layer resistivity from smoothed data, and Cartesian graphs of resistivity in relation to depth for 94 sites located in northeastern Palm Beach County. (USGS)

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USGS1988

Description and evaluation of the effects of urban and agricultural development on the surficial aquifer system, Palm Beach County, Florida

The surficial aquifer system in Palm Beach County was studied during 1982-85 to determine the effects of increased urban and agricultural development on groundwater levels, flow directions, and quality. The surficial aquifer system and its geologic matrix are divisible into three zones on the bases of relative permeabilities and lithologic characteristics. The two greatest water users in the county, public supply utilities and agricultural irrigators, increased total water withdrawals by 123 and 50%, respectively, during 1970-80. By 1980, 76% of public supply withdrawals were from zones I and II of the surficial aquifer system, whereas groundwater pumpage for irrigation decreased to 9% of the total irrigation water used. Increases in groundwater withdrawals for public supply were greatest in the southeast and central coastal parts of the county and served as an indicator for potential changes of flow directions and water quality in the surficial aquifer system. Residual seawater, emplaced in the aquifer system during the Pleistocene Epoch, is still prevalent in the central and western parts of Palm Beach County where low permeabilities in the geologic matrix have retarded its dilution. Chemical analyses of canal-water and groundwater samples collected in April 1984 were used to evaluate the effects of groundwater/surface water exchange on the quality of water during canal conveyance across the area containing residual seawater.

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USGS1986

Index of hydrologic data for selected sites in Palm Beach County, Florida, 1928-80

A regional assessment of the surficial aquifers in Dade, Broward , and Palm Beach Counties, Florida, including the Biscayne aquifer, was begun in 1979 by the U.S. Geological Survey, in cooperation with the South Florida Water Management District. The purpose of the first phase of the project was to determine the geologic, hydrologic, and water quality data available in the files of the U.S. Geological Survey and other public agencies. This report summarizes, through tables and maps, the types of data available for Palm Beach County.

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USGS1985

Altitude of water table, surficial aquifer, Palm Beach County, Florida, April 24-26, 1984

Water levels in Palm Beach County, Florida, were measured in April 1984 to determine the altitude of the water table in the surficial aquifer. A total of 104 wells and 50 surface-water measurement sites were used to contour the altitude of the water table at 2 and 4-foot intervals. The water-level measurements made in April represent low-water levels near the end of south Florida 's dry season. Contours of the water table at this time ranged from 22 feet above sea level in the north-central part of the county to 2 feet near the coast. (USGS)

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USGS1984

Hydrogeology of a zone of secondary permeability in the surficial aquifer of eastern Palm Beach County, Florida

The surficial aquifer is the primary source of freshwater for the heavily developed coastal area in eastern Palm Beach County, Florida. Well fields are generally located in a discontinuous zone of higher secondary permeability, the northernmost extension of the Biscayne aquifer in the surficial aquifer, that extends from the Juno Beach area south to Broward County and varies in width from about 4 to 15 miles. The zone was formed by varying dissolution of aquifer limestone materials during Pleistocene age changes in sea level, and ranges in depth from about sea level to 220 feet below sea level. Because of proximity to the Atlantic Ocean and saltwater estuaries, the aquifer is susceptible to saltwater intrusion. Ground water to the west of the zone of higher secondary permeability is of poor quality. The ground water is calcium bicarbonate dominant. Dissolved solids, calcium carbonate hardness, and chloride are greatest along the saltwater intruded coastline and in the western part of the study area where diluted residual seawater exists. Total organic carbon increases inland due to infiltration of rainwater through thicker layers of organic soils. Ground-water levels in the surficial aquifer in eastern Palm Beach County are strongly influenced by controlled levels in canals. In March 1981, after 12 months of below average rainfall, ground-water levels ranged from about 2 feet above sea level along the coast to nearly 21 feet above sea level 15 miles inland in the northwest section of the study area. (USGS)

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USGS1977

Hydraulic conductivity and water quality of the shallow aquifer, Palm Beach County, Florida

Subsurface geophysical logs were correlated with logs of drill cuttings to determine the permeability of selected zones of the shallow aquifer, Palm Beach County, Fla. The hydraulic conductivity of the aquifer is estimated to range from 1 to 130 feet per day, based on lithology and physical properties. The yield of wells penetrating this aquifer ranges from 100 to more than 1,000 gallons per minute. Water samples were collected from different depths throughout the county and analyzed for chemical constituents. Stiff diagrams illustrate the changes in types of water by depth and area. Water of suitable quality is in the eastern parts of the county. In this area the aquifer is the thickest and most permeable. The concentration of chemical constituents in the water increase in a westerly direction. The water in the western parts of the county is unsuitable for most purposes. (Woodard-USGS)

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USGS1977

Ground-water resources of the Riviera Beach area, Palm Beach County, Florida

The principal source of freshwater that has been developed in the Riviera Beach area is the so-called shallow aquifer, which is composed of sand, shells, sandstone, limestone, marl, and occasionally clay strata. Often a stratum contains mixtures of two or more of these materials and occasionally they are cemented. The aquifer ranges in thickness from approximately 300 feet at Lake Worth to less than 175 feet in the interior. The major water-bearing zone usually consists of cemented layers of sand and shells, about 100 feet thick, in the lower part of the aquifer. The quality of water in the shallow aquifer is generally suitable for municipal use except for an area along C-17 Canal where the dissolved solids concentration exceeds 500 milligrams per liter. The primary source of recharge to the shallow aquifer is rainfall. Discharge is mainly by evapotranspiration. Other discharges include seepage into drainage canals and Lake Worth, and pumpage. The configuration of the water table is greatly influenced by Lake Worth, C-17 Canal, West Palm Beach water catchment area, rainfall, and municipal pumpage. The major threat to development of water supplies, and possibly to the continuation of a current withdrawal rate of over 5 million gallons per day, is seawater intrusion. The municipal supply wells are almost 1 mile inland from the source of the seawater (Lake Worth), but the combined effects of increased pumpage, reduced recharge resulting from increased land development, and below normal rainfall, have caused seawater to advance inland in the aquifer. Additional supplies could be developed to the west, away from the threat of seawater intrusion.

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