Saline water intrusion from deep artesian sources in McGregor Isles area of Lee County, Florida

Upward leakage of saline water from an artesian aquifer below 1,500 feet has caused an increase in chloride concentration in the lower Hawthorn aquifer from less than 1,000 mg/1 (milligrams per liter) to values ranging from about 1,300 to 15,000 mg/1. Similarly the higher temperatures of the intruding water has caused an increase in water temperatures in the aquifer from 82"F to values ranging from 83 to 93"F. The intruding water moves upward either through the open bore hole of deep wells or test holes, or along a fault or fracture system, which has been identified in the area. From these points of entry into the lower Hawthorn aquifer, the saline water spreads laterally toward the south and southeast, but is generally confined to components of the fault system. The saline water moves upward from the lower Hawthorn aquifer into the upper Hawthorn aquifer through the open bore hole of wells, which connect the aquifers. This movement has resulted in an increase in chloride from less than 200 mg/1 in the unaffected parts of the upper Hawthorn aquifer to values commonly ranging from about 300 to more than 3,000 mg/1 in parts of the aquifer affected by upward leakage. The upper Hawthorn aquifer is the principal source of ground-water supply for public water-supply systems in western Lee County. Similar effects have been noted in the water-table aquifer, where chloride increased from less than 100 to concentrations ranging from about 500 to more than 5,000 mg/1. This was caused by the downward infiltration of water discharged at land surface from wells tapping the lower Hawthorn aquifer. The spread of saline water throughout most of the McGregor Isles area is continuing as of 1971. (40 page document)

Records of hydrologic data, Walton County, Florida

This report presents discharge, chemical analyses, temperatures, and specific conductance records collected at 25 surface-water sites and chemical analyses of ground water, well descriptions and records of ground-water levels collected at 164 ground-water sites. It also contains 35 logs of the sedimentary rocks penetrated in the drilling of wells and test borings ranging in depth from 147 to 625 feet. These hydrologic data were collected as part of an investigation of the water resources of the county. The interpretative results of the investigation are in the report entitled, "Water resources of Walton County," by C. A. Pascale (in preparation, 1971). (108 page document)

2007 Annual Report: Hydrologic Conditions in Baseflow Reaches Pursuant to Conditions 14 and 15, Santa Lucia Preserve, Monterey County, California

This report presents the results of the 2007 baseflow condition surveys of the four major streams flowing through Santa Lucia Preserve- Las Garzas, Portrero, San Jose, and San Clemente Creeks. This report has been prepared for the Santa Lucia Conservancy and is primarily intended for the staff of Monterey County and California Department of Fish and Game, in accordance with the baseflow monitoring and reporting requirements outlined in County Conditions 14 and 15. The scope of this report is limited to the presentation and evaluation of existing baseflow conditions as required by Conditions 14 and 15, and is not intended as a comprehensive analysis. However, data presented here are an important part of the long term data set that will be used for future in depth watershed analyses. (Document contains 13 pages & 14 figs)

Reconnaissance of the ground-water resources of Baker County, Florida

Ground-water is not widely used in Baker County, but the presence of a high equipotential area in the artesian system beneath the County made it necessary that the resource be understood insofar as this high affected the ground-water resources of Nassau and Duval counties which were being intensively studied and mapped. The method and rates of movement of ground-water from one point to another in the artesian aquifer are understood more fully by use of the data in this report. (PDF contains 30 pages)

Ground water in the Immokalee area, Collier County, Florida

The scope of the investigation involved the drilling of test holes and the detailed inventorying of existing wells in order to define the location, depth, potential yield, and chemical quality of the water contained in the shallow aquifer that might be used for the development of a central water-supply system. The field work and collection of data for the investigation covered the period 1961 through 1963. Much of the data collected for the report on the ground-water resources of Collier County (McCoy, 1962) is incorporated into this report. (Document has 36 pages.)

Characterization of the sediments overlying the Floridan aquifer system in Alachua County, Florida

The primary purpose of this project is to attempt to improve the existing hydrogeologic information through lithologic and hydrogeologic characterizations of the sediments overlying the Floridan aquifer system in Alachua County. These sediments locally comprise both the intermediate aquifer system and associated confining beds and the surficial aquifer system. (PDF has 119 pages.)

Lithology and palynology of cave floor sediment cores from Wakulla Spring, Wakulla County, Florida

Five short bottom sediment cores taken in Wakulla Spring Wakulla County, Florida, were described lithologically and sampled for palynological study. Four of the cores were recoveredfrom sediments at the spring cave entrance (130 feet water depth). One core was taken in a fossil vertebrate bone bed, 280 feet distance into the main spring cave at a water depth of 240 feet. Sediments in the cores are composed of alternating intervals of quartz sand and calcilitite, containing freshwater diatoms, freshwater mollusk shells and plant remains. The predominant pollen present in all cores consists of a periporate variety typical of the herb families Chenopodiaceae and Amaranthaceae. Arboreal flora, typical of the area surrounding the spring today, represent a very low percentage of thle pollen assemblage in the cores. Clustered Chenopod-Amaranth type pollen observed in one core suggest minimal transport prior to deposition, and indicate that the bottom sediments in the cave may be essentially In situ. An absence of exotic flora suggests a Quaternary age for the sediments. (PDF contains 11 pages.)

The artesian water of the Ruskin area of Hillsborough County, Florida: interim report

The purpose of the investigation is to make a detailed study of the geology and ground water in the Ruskin area, especially as related to the problem of salt-water encroachment. The major objectives of the program includes: (1) An inventory of wells to determine their number and distribution, their depths and diameters, and other pertinent information. (2) A study of artesian pressures. (3) Analyses of water from selected wells to determine the location and extent of any areas in which the artesian water is salty. (4) A study of the surface and subsurface geology as related to the occurrence and movement of ground water. (5) An estimate of the quantity of ground water withdrawn. (PDF contains 24 pages.)

Interim report on the ground-water resources of Seminole County, Florida

Salt-water encroachment is undoubtedly the problem of most concern to users of ground water in Florida. This is a problem in many coastal areas where water levels are lowered excessively by heavy pumping. It is a problem also in some inland areas where the water-bearing formations contain salty water at relatively shallow depths. Among the coastal areas where wells have become contaminated with salt water are Pinellas County and the Miami area of Dade County. Inland areas where wells are likely to become contaminated with salt water include Seminole County and the southwestern part of Volusia County. The purpose of the investigation is to make a detailed study of the geology and ground-water resources of the county with special emphasis on the problems associated with declining water levels and salt-water contamination. This report reviews briefly the progress of the investigation through February 1954. (PDF contains 43 pages.)

Interim report on the ground-water resources of Manatee County, Florida

A large part of western Manatee County is devoted to the growing of winter vegetables and citrus fruits. As in most of peninsular Florida, rainfall in the county during the growing season is not sufficient for crop production and large quantites of artesian water are used for irrigation. The large withdrawals of artesian water for irrigation result in a considerable decline of the artesian head in the western part of the county. This seasonal decline of the artesian head has become larger as the withdrawal of artesian water has increased. The lowering of the fresh-water head in some coastal areas in the State has resulted in an infiltration of sea water into the water-bearing formations. The presence of salty water in the artesian aquifer in parts of the coastal area of Manatee County indicates that sea water may also have entered the waterbearing formations in this area as a result of the decline of artesian pressure during the growing season. The purpose of the investigation is to make a detailed study of the geology and ground-water resources of the county, primarily to determine whether salt-water encroachment has occurred or is likely to occur in the coastal area. (PDF contains 38 pages.)

Interim report on surface water resources and quality of waters in Lee County, Florida

Report seeks to address following questions: 1. Where within Lee County are surface supplies of water located? 2. What are the variations in this supply? 3. What can be done to provide better answers to questions 1 and 2 than are available at the present time? (PDF contains 76 pages.)

Interim report on salt-water encroachment in Dade County, Florida

Recently there has been much activity in reclaiming the low-lying coastal areas of Dade County for residential use, by the addition of fill. The fill is obtained by digging canals both normal to and parallel to Biscayne Bay. The canals serve the additional purpose of providing an access to the Bay for boats. A problem needing to be considered is the effect that these canals will have on the ground-water resources. It is expected that the canals will have little effect on ground water in parts of the county distant from the coast, but their effect in coastal areas is a matter of concern. In order to predict what, may happen in the vicinity of these new canals if they are not equipped with adequate control structures, it is instructive to review what has happened in the vicinity of similar canals in the past. The U. S. Geological Survey, in cooperation with Dade County, the cities of Miami and Miami Beach, the Central and Southern Florida Flood Control District, and the Florida Geological Survey has collected water-level and salinity data on wells and canals in Dade County since 1939. Some of the agencies named, and others, collected similar data before 1939. Analysis of all the data shows that sea water in the Atlantic Ocean and Biscayne Bayis the sole source of salt-water contamination in the Biscayne aquifer of the Dade County area. (PDF has 19 pages.)

Ground-water resources of the Stuart area, Martin County, Florida

Because the Stuart area is, at times, surrounded on three sides by saline water, the underlying fresh-water aquifer is vulnerable to salt-water encroachment. With progressively larger withdrawals of ground water for public and private supplies, the possibility of salt-water contamination of freshwater supplies is increased. (PDF contains 51 pages.)

Changes in the chloride content of ground water in Pinellas County, Florida between 1947 and 1956

In December 1956 the U. S. Geological Survey, in cooperation with the Florida Geological Survey and the Board of County Commissioners of Pinellas County, collected waterlevel and chloride content of water in 94 wells in Pinellas County. First sampled in 1947, resampling and reanalyzing the water from these wells was used to determine the change in the chloride content of the ground water from 1947 to 1956. The chloride content of ground water is generally a reliable indication of the contamination of ground water by sea water, as 90 percent of the dissolved solids of sea water are chloride salts. (PDF contains 15 pages.)

Record of wells in Manatee County, Florida

A detailed study of the geology and ground-water resources of Manatee County (fig. 1) was made during the period from 1950 to 1955. This report contains a table of well records that was compiled from data collected during that investigation. The well-numbering system used in the table is based on latitude and longitude. (PDF contains 204 pages.)