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USGS2002

Cruise report RV Moana Wave Cruise M-1-02-GM bathymetry and acoustic backscatter of the mid and outer continental shelf, head of De Soto Canyon, northeastern Gulf of Mexico June 17, through July 9, 2002 Pensacola, FL to Pensacola, FL

The mid to outer continental shelf off Mississippi-Alabama and off northwest Florida were the focus of US Geological Survey (USGS) multibeam echosounder (MBES) mapping cruises in 2000 and 2001, respectively. These areas were mapped to investigate the extent of "deep-water reefs" first suggested by Ludwick and Walton (1957). The reefs off Mississippi and Alabama were initially described in water depths of 60 to 120 m (Ludwick and Walton, 1957) but the 2000 mapping found reef and hardgrounds to be much more extensive than previously thought (Gardner et al., 2001). The persistent trend of reef-like features along the outer shelf of Mississippi-Alabama suggested the trend might continue along the northwest Florida mid and outer shelf so a MBES-mapping effort was mounted in 2001 to test this suggestion. It is critical to determine the accurate location, geomorphology, and types of the ridges and reefs that occur in this region to understand the Quaternary history of the area and to assess their importance as benthic habitats for fisheries. The 2001 survey found a series of shelf-depth platforms with ridges (possibly reefs) constructed on their surfaces (Gardner et al., 2002). The area known as the "head of De Soto Canyon" is the large unmapped region between the 2000 and 2001 mapped areas. The head of De Soto Canyon is an outer shelf zone with a relatively steep western wall and a much gentler eastern wall. It was unknown prior to this cruise whether the reefs of the Mississippi-Alabama shelf continue eastward into the head of De Soto Canyon and connect with the ridges and reefs mapped on the northwest Florida outer shelf. The existence of carbonate-cemented latest Quaternary to Holocene sandstones along the western wall of the head of De Soto Canyon (Shipp and Hopkins, 1978; Benson et al., 1997; W.W. Schroeder, personnel comm., 2002) is of interest because of the potential benthic habitats they may represent. Precisely georeferenced high-resolution mapping of bathymetry is a fundamental first step in the study of an area suspected to be critical benthic habitats. Morphology is thought to be critical to define the distribution of dominant demersal plankton/planktivores communities. Community structure and trophodynamics of demersal fishes of the outer continental shelf of the northeastern Gulf of Mexico presently are focuses of a major USGS research project. A goal of the project is to answer questions concerning the relative roles played by morphology and surficial geology in controlling biological differentiation. Deep-water ridges, reefs, and outcrops are important because they are fish havens and key spawning sites, and are critical habitats for larval, juvenile, and economically important sport/food fishes.

Gulf of Mexico, head Of De Soto Canyon↗

USGS1995

Bathymetry, freshwater flow, and specific conductance of Matlacha Pass, southwestern Florida

The Matlacha Pass estuary, a State of Florida aquatic preserve, is bounded by Pine Island to the west, Cape Coral to the east, Charlotte Harbor to the north, and the Caloosahatchee River to the south (fig. 1). The estuary is important for its aesthetic value; used for recreational boating, sport and commercial fishing, tourism, and residential development; and is a nursery for fish and invertebrates. Historically, freshwater runoff from Cape Coral entered Matlacha Pass estuary as sheetflow. As development occurred on Cape Coral, canals were designed and constructed to collect the freshwater runoff and distribute it as sheetflow through two spreader canal systems into Matlacha Pass. Water managers have expressed concern that altering the freshwater runoff patterns into the pass could have a detrimental effect on salinity distribution which might adversely affect the aquatic system of the pass. Adequate data were not available to evaluate the freshwater flow, its movement, and mixing. The U.S. Geological Survey, in cooperation with the City of Cape Coral, Lee County, and the Florida Department of Environmental Protection, conducted a study from July 1989 to September 1992 to identify three hydrodynamic aspects for managing the estuary.

Florida↗

USGS1973

Reconnaissance of water quality in the vicinity of Sunniland Oil Field, Collier County, Florida, 1971-72

Oil exploration in Florida began around the turn of the century in Escambia County (Gunter, 1949). Many test wells were drilled from 1900 until Humble Oil and Refining Company developed Florida's first producing well (Gulf Coast Realties Corp. No. 1) in September 1943 at Sunniland. (See fig. 1.) The first production well was drilled to 11,626 feet below sea level and had an initial production of 97 barrels of oil per day. Since this first well was developed many more have been drilled in the Sunniland field, and at this time (1973) 17 wells are producing about 50,000 barrels of oil per month (W. R. Oglesby, written commun., 1972). The Sunniland field, in north central Collier County, remained the chief oil producing field in Florida until 1966 when the Sunoco-Felda field, about 20 miles north of the Sunniland field, began producing more oil (Babcock, 1970). Oil produced in both fields is transported by pipeline to Port Everglades, on the east coast. Anticipation of oil exploration in the Big Cypress area (fig. 1) aroused concern the effects a producing field would have on the quality of surface water in the area. The Florida Department of Natural Resources requested the U.S. Geological Survey to determine whether there have been any such effects. The 29-year old Sunniland oil field was chosen for this preliminary evaluation. A second phase of the investigation was to monitor the effects of building roads, drilling operations and other exploratory activities related to development of an oil field, on the quality of surface water in the areas of proposed exploration. This report presents the results of the first phase.

Florida↗

USGS1983

Quality-assurance data for routine water analysis in the laboratories of the US Geological Survey; 1981 annual report

The U.S. Geological Survey maintains a quality-assurance program based on the analysis of reference samples for its two water-analysis laboratories located in Atlanta, Georgia and Denver, Colorado. Reference containing inorganic constituents are prepared at the U.S. Geological Survey 's Ocala, Florida, office and disguised as routine samples, and sent daily to each laboratory through other U.S. Geological Survey offices. The results are permanently stored in the National Water Data Storage and Retrieval System (WATSTORE), the U.S. Geological Survey 's data base for all water data. These data are analyzed statistically for precision and bias. The results of these statistical analyses are presented for data collected during the 1981 calendar year. In addition, one sample containing known concentrations of trihalomethanes and samples containing unknown concentrations of chlorophyll a were analyzed in both laboratories, and these results also are presented. (USGS)

Water-Resources Investigations Report↗

USGS1996

Ground-water quality assessment of the Georgia-Florida Coastal Plain study unit — Analysis of available information on nutrients, 1972-92

The U.S. Geological Survey is conducting an assessment of water quality in the Georgia-Florida Coastal Plain study unit as part of the National Water-Quality Assessment Program. An initial activity of the program is to compile and analyze existing water-quality data for nutrients in each study unit. Ground-water quality data were compiled from three data sources, the U.S. Geological Survey, Florida Department of Environmental Protection, and Georgia Geologic Survey. A total of 2,246 samples of ground water nutrient data for nitrogen and phosphorus species were compiled from these three data sources. Estimates of 1990 nitrogen and phosphorus inputs by county in the study area were calculated from livestock manure, fertilizers, septic tanks, and rainfall. Data for nitrate nitrogen concentrations in ground water were available from the greatest number of wells; samples from 1,233 wells were available in the U.S. Geological Survey, 820 wells from the Florida Department of Environmental Protection, and 680 wells from the Georgia Geologic Survey. The maximum contaminant level for nitrate nitrogen in drinking water of 10 milligrams per liter was exceeded in a higher percentage of samples from the U.S. Geological Survey, mostly because this data contained numerous samples near known contamination areas. The maximum contaminant level for nitrate nitrogen was exceeded in 3 percent of samples from Upper Floridan aquifer and 12 percent of samples from surficial aquifer system in U.S. Geological Survey data and less than 1 percent and 2 percent of samples from the Upper Floridan aquifer and surficial aquifer system, respectively, in Florida Department of Environmental Protection data. In Georgia Geologic Survey data, 1 percent of samples had concentrations of nitrate nitrogen exceeding 10 milligrams per liter. Nutrient concentration data were grouped into categories based on land use, hydrogeology (aquifer and confinement of the Upper Floridan aquifer), and land resource provinces (Central Florida Ridge, Coastal Flatwoods and Southern Coastal Plain) for the surficial aquifer system. The highest median nitrate nitrogen concentrations in the U.S. Geological Survey data were 0.4 milligrams per liter in ground-water samples from the unconfined Upper Floridan aquifer in agricultural areas and 9.0 milligrams per liter in samples from the surficial aquifer system in agricultural areas in the Central Florida Ridge. In Florida Department of Environmental Protection data, the highest median nitrate nitrogen concentrations were much lower and did not exceed 0.2 milligrams per liter in either the Upper Floridan aquifer or the surficial aquifer system. In Georgia Geologic Survey data the highest median nitrate nitrogen concentration was 1.4 milligrams per liter in agricultural areas in the Coastal Flatwoods. Highest median concentrations of total nitrogen of 10 milligrams per liter (includes nitrate, ammonia, and organic nitrogen) were in U.S. Geological Survey data in the surficial aquifer system in agricultural areas in the Central Florida Ridge. Median concentrations of ammonia nitrogen, orthophosphate phosphorus, and total phosphorus did not exceed 0.5 milligrams per liter in all categories from the Upper Floridan aquifer or the surficial aquifer system.

Florida, Georgia↗

USGS2015

Field observations of artificial sand and oil agglomerates

Oil that comes into the surf zone following spills, such as occurred during the 2010 Deepwater Horizon ( DWH ) blowout, can mix with local sediment to form heavier-than-water sand and oil agglomerates ( SOAs ), at times in the form of mats a few centimeters thick and tens of meters long. Smaller agglomerates that form in situ or pieces that break off of larger mats, sometimes referred to as surface residual balls ( SRBs ), range in size from sand-sized grains to patty-shaped pieces several centimeters ( cm ) in diameter. These mobile SOAs can cause beach oiling for extended periods following the spill, on the scale of years as in the case of DWH . Limited research, including a prior effort by the U.S. Geological Survey ( USGS ) investigating SOA mobility, alongshore transport, and seafloor interaction using numerical model output, focused on the physical dynamics of SOAs . To address this data gap, we constructed artificial sand and oil agglomerates ( aSOAs ) with sand and paraffin wax to mimic the size and density of genuine SOAs . These aSOAs were deployed in the nearshore off the coast of St. Petersburg, Florida, during a field experiment to investigate their movement and seafloor interaction. This report presents the methodology for constructing aSOAs and describes the field experiment. Data acquired during the field campaign, including videos and images of aSOA movement in the nearshore (1.5-meter and 0.5-meter water depth) and in the swash zone, are also presented in this report.

Florida↗

USGS1989

U.S. Geological Survey second national symposium on Water quality; abstracts of the technical sessions, Orlando, Florida, November 12-17, 1989

The U.S Geological Survey (USGS) compiled and analyzed existing hydrologic and water-quality data from over 200 stream and estuary stations of the Abemarle-Pamlico estuarine system (A/P) to identify long-term temporal and spatial trends. The dataset included seven stations of the USGS National Stream Quality Accounting Network, two stations of the National Atmospheric Precipitation Deposition monitoring network, stations of the N.C. Department of Natural Resources and Community Development, and stations from 25 reports by individual investigators. Regression-residuals analysis, the seasonal Kendall's Tau test for trends, and graphical analysis using annual box plots were employed to determine trends. Profound change has occurred in the water quality of the A/P area over the last 30 years. Analysis of water-quality data upstream from the estuaries indicates increases of discharge-adjusted values of specific conductance, alkalinity, phosphorous, hardness, chloride, and dissolved solids. In the estuaries, pH is increasing except in the Pamlico River, where it is decreasing. There is a generalized decrease in suspended inorganic material in the system. Salinities are decreasing for sections of the Pamlico River, and increasing for parts of Albemarle Sound. Nitrogen concentrations are decreasing except in the Pamlico River, where they are increasing. Phosphorus concentrations are increasing in the Pamlico River and decreasing elsewhere. Annual average data show that nitrogen is the limiting nutrient in the Neuse and Pamlico Rivers. Phosphorus is limiting in the rest of the area. Chlorophyll-a levels are increasing in parts of the Neuse and Pamlico Rivers and decreasing in parts of the Chowan River. To evaluate the effect of basin characteristics on water quality, linear correlation was used. Agricultural crop variables produced the most correlations with water-quality data. Fertilizer usage had little detectable relation to water quality in the study area. In the section of the Pamlico River near Aurora, relations between employment, road mileages, and water quality indicated effects of development in the area.

Open-File Report↗

USGS1979

Water-quality data from a landfill, Pinellas County, Florida, May 1975-October 1977

Ground water in and near a proposed landfill site can become contaminated by leachates from the fill material. Realizing that potential, Pinellas County entered into a cooperative investigation with the U.S. Geological Survey to determine background water-quality conditions, and to evaluate the potential effects of landfill leachate on the quality of ground water at a landfill site in Pinellas County (fig. 1). The investigation started in May 1975 and landfill operation began in November 1975. The purpose of this report is to make available well records, logs of wells, and surface- and ground-water quality data for planning purposes, and to provide basic data for a subsequent interpretive report. From May 1975 to October 1977, surface- and ground-water samples were collected periodically to obtain information on certain background water-quality conditions at the landfill site. Specific conductance and pH were determined in the field. Sodium, potassium, calcium, magnesium, chloride, trace metals, chemical and biochemical oxygen demands, coliform, select herbicides and pesticides, and nitrogen and phosphorus species were determined in the laboratory.

Florida↗

USGS2008

Borehole Geophysical Logging Program: Incorporating New and Existing Techniques in Hydrologic Studies

The borehole geophysical logging program at the U.S. Geological Survey (USGS)-Florida Integrated Science Center (FISC) provides subsurface information needed to resolve geologic, hydrologic, and environmental issues in Florida. The program includes the acquisition, processing, display, interpretation, and archiving of borehole geophysical logs. The borehole geophysical logging program is a critical component of many FISC investigations, including hydrogeologic framework studies, aquifer flow-zone characterization, and freshwater-saltwater interface delineation.

Fact Sheet↗

USGS1982

Physical, Hydrological, and Biological Characteristics of the Loxahatchee River Estuary, Florida

The Loxahatchee River estuary empties into the Atlantic Ocean at Jupiter Inlet in southeastern Florida. Although relatively small, the estuary is important for its esthetic value and for its sport fishing, boating, recreation, tourism, and prime residential development. In recent years, the condition of the estuary has become of concern to many citizens and agencies of the State. In response to this concern, the U.S. Geological Survey planned and carried out an in-depth environmental investigation. The events that led to the investigation and the objectives of the investigation are outlined in a recent U.S. Geological Survey report by McPherson and Sabanskas (WRI 80-1109).

Water-Resources Investigations Report↗

USGS1999

Delineation of saltwater intrusion in the surficial aquifer system in eastern Palm Beach, Martin, and St. Lucie counties, Florida, 1997-98

Urban development in Palm Beach, Martin, and St. Lucie Counties, Fla. (fig. 1), has expanded rapidly in recent decades, resulting in a need for additional freshwater withdrawals from the surficial aquifer system--the primary source of drinking water for this tri-county area. Potable-water demand for urban users is projected to increase 115 percent in Palm Beach County and 89 percent each in Martin and St. Lucie Counties 1990 to 2010 (South Florida Water Management District, 1998). The increased demand on the coastal well fields, which draw water from the surficial aquifer system, may contribute to saltwater intrusion. There are limited data as to the location or movement of the saltwater interface in the tri-county area, with the exception of previously collected data in the immediate vicinity of the existing coastal well fields. It is possible that the combination of pumpage from the well fields and drainage caused by rivers and canals has a regional effect on the saltwater interface. In October 1996, the U.S. Geological Survey (USGS) entered into a cooperative study with the South Florida Water Management District (SFWMD) to determine the present location of the interface between freshwater and oceanic saltwater in the surficial aquifer system along the coast of southeastern Florida. This map report documents the position of the saltwater interface in the surficial aquifer system in 1997-98 through the evaluation of chloride and geophysical data.

Florida↗

USGS2001

Simulation of the interaction of karstic lakes Magnolia and Brooklyn with the upper Floridan Aquifer, southwestern Clay County, Florida

The stage of Lake Brooklyn, in southwestern Clay County, Florida, has varied over a range of 27 feet since measurements by the U.S. Geological Survey began in July 1957. The large stage changes have been attributed to the relation between highly transient surface-water inflow to the lake and subsurface conduits of karstic origin that permit a high rate of leakage from the lake to the Upper Floridan aquifer. After the most recent and severe stage decline (1990-1994), the U.S. Geological Survey began a study that entailed the use of numerical ground-water flow models to simulate the interaction of the lake with the Upper Floridan aquifer and the large fluctuations of stage that were a part of that process. A package (set of computer programs) designed to represent lake/aquifer interaction in the U.S. Geological Survey Modular Finite-Difference Ground-Water Flow Model (MODFLOW-96) and the Three-Dimensional Method-of-Characteristics Solute-Transport Model (MOC3D) simulators was prepared as part of this study, and a demonstration of its capability was a primary objective of the study. (Although the official names are Brooklyn Lake and Magnolia Lake (Florida Geographic Names), in this report the local names, Lake Brooklyn and Lake Magnolia, are used.) In the simulator of lake/aquifer interaction used in this investigation, the stage of each lake in a simulation is updated in successive time steps by a budget process that takes into account ground-water seepage, precipitation upon and evaporation from the lake surface, stream inflows and outflows, overland runoff inflows, and augmentation or depletion by artificial means. The simulator was given the capability to simulate both the division of a lake into separate pools as lake stage falls and the coalescence of several pools into a single lake as the stage rises. This representational capability was required to simulate Lake Brooklyn, which can divide into as many as 10 separate pools at sufficiently low stage. In the first of two calibrated models, recharge to the water table, specified as a monthly rate, was set equal to 40 percent of the monthly rainfall rate. The specified rate of inflow to the uppermost stream segment was set equal to outflows from Lake Lowry estimated from lake stage and the 1994-97 rating table. Leakage to the intermediate and Upper Floridan aquifers was assumed to occur from the surficial aquifer system through the confining layers directly beneath deeper parts of the lake bottom. A leakance coefficient value of 0.001 feet per day per foot of thickness was used beneath Lake Magnolia, and a value of 0.005 feet per day per foot of thickness was used beneath most of Lake Brooklyn. With these values, the conductance through the confining layers beneath Lake Brooklyn was about 19 times that beneath Lake Magnolia. The simulated stages of Lake Brooklyn matched the measured stages reasonably well in the early (1957-72) and later (1990-98) parts of the simulation time period, but the match was unsatisfactory in an intermediate time period (1973-89). To resolve this discrepancy, the hypothesis was proposed that undocumented losses of water from Alligator Creek upstream from Lake Brooklyn or from the lake itself occurred between 1973 and 1989 when there was sufficient streamflow. The resulting simulation of lake stages matched the measured lake stages accurately during the entire simulation time period. The model was then revised to incorporate the assumption that only 20 percent of precipitation recharged the water table (the second calibrated model). Recalibration of the model required that leakance values for the confining units under deeper parts of the lakes also be reduced by nearly 50 percent. The stages simulated with the new parameter assumptions, but retaining the assumption of surface-water losses, were an excellent match of the measured values. The stage of Lake Magnolia was also simulated accurately. The results of sensitivity analyses show that simulated streamflow between Lakes Magnolia and Brooklyn tends to be water-budget controlled, and is not appreciably affected by the specified outflow altitude or channel characteristics of the receiving stream. To match heads measured in observation wells of the surficial aquifer network, the assigned hydraulic conductivity values were zoned, and ranged from a minimum of 4 feet per day to a maximum of 400 feet per day in the first calibrated model. These values were reduced by about 50 percent in the second calibrated model. Differences between observation wells were noted in the abruptness of changes of measured head values, and in the relation of the timing of peak measured heads and simulated peak heads. These differences seemed to be correlated with the depth of the water table below land surface. Spatially uniform values of transmissivity were specified for the intermediate (10,000 feet squared per day) and Upper Floridan (100,000 feet squared per day) aquifers. Simulated heads in the Upper Floridan aquifer layer follow the trend of the heads measured in a long-term observation well with data beginning in 1960. This result suggests that the observed head decline could be explained entirely in terms of the stage decline in Lake Brooklyn and may not indicate a regional trend.

Florida↗

USGS2004

Assessment of ground-water withdrawals at municipal industrial parks in Puerto Rico, 2000

An assessment of ground-water withdrawals at municipal industrial parks throughout Puerto Rico was conducted to investigate the effect of ground-water usage on nearby surface- and ground-water resources. Water-bearing strata were divided into four generalized hydrogeologic units: (1) fissured aquifers (including karst and non-karst limestone); (2) intergranular aquifers; (3) intergranular aquifers overlying fissured rock units; and (4) strata with local or limited ground-water resources. Approximately 49 percent of the municipal industrial parks are located in areas with local or limited ground-water resources, 29 percent overlie intergranular aquifers, 13 percent overlie fissured aquifers, and 9 percent overlie intergranular units that overlie fissured rock units. Hydrogeologic data for the generalized hydrogeologic units were compiled from published U.S. Geological Survey reports. Depths to ground water near industrial parks range from approximately 20 to 400 feet in the fissured aquifers, 6 to 65 feet in coastal intergranular aquifers, 3 to 30 feet in intergranular aquifers overlying fissured rock units, and 1 to 100 feet in strata with local or limited ground-water resources. Aquifer transmissivities near industrial parks range from approximately 100,000 feet squared per day in the fissured aquifers to less than 100 feet squared per day in the strata with local or limited ground-water resources. Well construction data were compiled from published U.S. Geological Survey reports, drillers? logs, and unpublished reports. Specific capacity for wells near industrial parks ranges from approximately 100 gallons per minute per foot of drawdown in the fissured aquifer at Manati to approximately 0.1 gallon per minute per foot of drawdown in strata with local and limited ground-water resources at Bayamon. Reported well yields near industrial parks ranges from 2,800 gallons per minute in the intergranular aquifer at Santa Isabel to approximately 3 gallons per minute in strata with local and limited ground-water resources at Adjuntas. Historical ground-water-level data from U.S. Geological Survey observation wells were used to define ground-water levels trends in the vicinity of industrial parks. Areas showing ground-water level declines, and therefore possible aquifer over-development, are located in Barceloneta and Guayama. Rising ground-water levels were noted in the vicinity of industrial parks at Florida, Ponce, and Yauco. Ground-water withdrawal data were compiled from site visits to the industrial facilities and from information provided by Puerto Rico Department of Natural and Environmental Resources. Total ground-water withdrawal at the municipal industrial parks was estimated to be 1.6 million gallons per day. Most withdrawals were from intergranular coastal aquifers, which accounted for about two thirds of the ground-water withdrawals. Municipal industrial parks with substantial ground-water withdrawals are located in Bayamon, Caguas, Humacao, and Ponce.

Scientific Investigations Report↗

USGS2002

The road to flamingo: An evaluation of flow pattern alterations and salinity intrusion in the lower glades, Everglades National Park

Introduction This report describes the history of roads through the Lower Glades of Everglades National Park, Florida and their influence on salinity intrusion. The chronology that lead to this work is interesting. The U.S. Geological Survey flew a series of helicopter electromagnetic surveys over portions of Everglades National Park to map saltwater intrusion starting in 1994 (Fitterman et al., 1995; Fitterman, 1996; Fitterman and Deszcz-Pan, 1998, 2002). These surveys identified variations in the electrical resistivity that were associated with changes in ground-water quality. The patterns of ground-water quality have been traced to natural saltwater intrusion, such as the effect of tidal rivers on lowering hydrologic heads far inland, and the influence of man-made structures, such as canals and roadways on surface water flow. These latter effects are of interest as they represent variations from the natural state of affairs in the park. Previous investigations had been done by Everglades National Park staff on the influence of some roads and canals on the near surface hydrology. This information was scattered through a number of National Park Service publications. In an effort to bring these materials together in an easily located reference, along with new data on flows through culverts beneath the main park road, this report was written.

Florida↗

USGS2010

Potentiometric Surface of the Upper Floridan Aquifer, West-central Florida, May 2010

The Floridan aquifer system consists of the Upper and Lower Floridan aquifers separated by the middle confining unit. The middle confining unit and the Lower Floridan aquifer in west-central Florida generally contain highly mineralized water. The water-bearing units containing fresh water are herein referred to as the Upper Floridan aquifer. The Upper Floridan aquifer is the principal source of water in the Southwest Florida Water Management District and is used for major public supply, domestic use, irrigation, and brackish water desalination in coastal communities (Southwest Florida Water Management District, 2000). This map report shows the potentiometric surface of the Upper Floridan aquifer measured in May 2010. The potentiometric surface is an imaginary surface connecting points of equal altitude to which water will rise in tightly-cased wells that tap a confined aquifer system (Lohman, 1979). This map represents water-level conditions near the end of the dry season, when groundwater levels usually are at an annual low and withdrawals for agricultural use typically are high. The cumulative average rainfall of 55.21 inches for west-central Florida (from June 2009 through May 2010) was 2.55 inches above the historical cumulative average of 52.66 inches (Southwest Florida Water Management District, 2010). Historical cumulative averages are calculated from regional rainfall summary reports (1915 to most recent complete calendar year) and are updated monthly by the Southwest Florida Water Management District. This report, prepared by the U.S. Geological Survey in cooperation with the Southwest Florida Water Management District, is part of a semi-annual series of Upper Floridan aquifer potentiometric-surface map reports for west-central Florida. Potentiometric-surface maps have been prepared for January 1964, May 1969, May 1971, May 1973, May 1974, and for each May and September since 1975. Water-level data are collected in May and September each year to show the approximate annual low and high water-level conditions, respectively. Most of the water-level data for this map were collected by the U.S. Geological Survey during the period May 17-21, 2010. Supplemental water-level data were collected by other agencies and companies. Most water-level measurements were made during a 5-day period; therefore, measurements do not represent a 'snapshot' of conditions at a specific time, nor do they necessarily coincide with the seasonal low water-level condition.

Scientific Investigations Map↗

USGS2004

A method for simulating transient ground-water recharge in deep water-table settings in central Florida by using a simple water-balance/transfer-function model

A relatively simple method is needed that provides estimates of transient ground-water recharge in deep water-table settings that can be incorporated into other hydrologic models. Deep water-table settings are areas where the water table is below the reach of plant roots and virtually all water that is not lost to surface runoff, evaporation at land surface, or evapotranspiration in the root zone eventually becomes ground-water recharge. Areas in central Florida with a deep water table generally are high recharge areas; consequently, simulation of recharge in these areas is of particular interest to water-resource managers. Yet the complexities of meteorological variations and unsaturated flow processes make it difficult to estimate short-term recharge rates, thereby confounding calibration and predictive use of transient hydrologic models. A simple water-balance/transfer-function (WBTF) model was developed for simulating transient ground-water recharge in deep water-table settings. The WBTF model represents a one-dimensional column from the top of the vegetative canopy to the water table and consists of two components: (1) a water-balance module that simulates the water storage capacity of the vegetative canopy and root zone; and (2) a transfer-function module that simulates the traveltime of water as it percolates from the bottom of the root zone to the water table. Data requirements include two time series for the period of interest?precipitation (or precipitation minus surface runoff, if surface runoff is not negligible) and evapotranspiration?and values for five parameters that represent water storage capacity or soil-drainage characteristics. A limiting assumption of the WBTF model is that the percolation of water below the root zone is a linear process. That is, percolating water is assumed to have the same traveltime characteristics, experiencing the same delay and attenuation, as it moves through the unsaturated zone. This assumption is more accurate if the moisture content, and consequently the unsaturated hydraulic conductivity, below the root zone does not vary substantially with time. Results of the WBTF model were compared to those of the U.S. Geological Survey variably saturated flow model, VS2DT, and to field-based estimates of recharge to demonstrate the applicability of the WBTF model for a range of conditions relevant to deep water-table settings in central Florida. The WBTF model reproduced independently obtained estimates of recharge reasonably well for different soil types and water-table depths.

Scientific Investigations Report↗

USGS2011

Potentiometric surface of the upper Floridan aquifer, west-central Florida, May 2011

The Floridan aquifer system consists of the Upper and Lower Floridan aquifers separated by the middle confining unit. The middle confining unit and the Lower Floridan aquifer in west-central Florida generally contain highly mineralized water. The water-bearing units containing freshwater are herein referred to as the Upper Floridan aquifer. The Upper Floridan aquifer is the principal source of water in the Southwest Florida Water Management District and is used for major public supply, domestic use, irrigation, and brackish water desalination in coastal communities (Southwest Florida Water Management District, 2000). This map report shows the potentiometric surface of the Upper Floridan aquifer measured in May 2011. The potentiometric surface is an imaginary surface connecting points of equal altitude to which water will rise in tightly-cased wells that tap a confined aquifer system (Lohman, 1979). This map represents water-level conditions near the end of the dry season, when groundwater levels usually are at an annual low and withdrawals for agricultural use typically are high. The cumulative average rainfall of 45.74 inches for west-central Florida (from June 2010 through May 2011) was 6.85 inches below the historical cumulative average of 52.59 inches (Southwest Florida Water Management District, 2011). Historical cumulative averages are calculated from regional rainfall summary reports (1915 to most recent complete calendar year) and are updated monthly by the Southwest Florida Water Management District. This report, prepared by the U.S. Geological Survey in cooperation with the Southwest Florida Water Management District, is part of a semi-annual series of Upper Floridan aquifer potentiometric-surface map reports for west-central Florida. Potentiometric-surface maps have been prepared for January 1964, May 1969, May 1971, May 1973, May 1974, and for each May and September from 1975 through 2010. Water-level data are collected in May and September each year to show the approximate annual low and high water-level conditions, respectively. Most of the water-level data for this map were collected by the U.S. Geological Survey during the period May 23-27, 2011. Supplemental water-level data were collected by other agencies and companies. Most water-level measurements were made during a 5-day period; therefore, measurements do not represent a "snapshot" of conditions at a specific time, nor do they necessarily coincide with the seasonal low water-level condition.

Florida↗

USGS2002

Flow-velocity, water-temperature and conductivity data collected in Shark River Slough, Everglades National Park, during 1999-2000 and 2000-2001 wet seasons

A project within the U. S. Geological Survey Place- Based Studies Program is focused on investigation of ?Forcing Effects on Flow Structure in Vegetated Wetlands of the Everglades.? Data-collection efforts conducted within this project at three locations in Shark River Slough, Everglades National Park, during the 1999-2000 and 2000-2001 wet seasons are described in this report. Techniques for collecting and processing the data and summaries of daily mean flowvelocity, water-temperature, and conductivity data are presented. The quality-checked and edited data have been compiled and stored on the USGS South Florida Information Access website.

Florida↗