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Geology topics

G. A. Irwin

Publications and source records attributed to G. A. Irwin.

14 recordsLinked to original sources
USGS1988

Effects of two stormwater management methods on the quality of water in the upper Biscayne aquifer at two commercial areas in Dade County, Florida

This study is part of a continued effort to assess the effects of urban stormwater recharge on the water quality of the Biscayne aquifer in southeast Florida. In this report, the water-quality effects on shallow ground water resulting from stormwater disposal by exfiltration trench and grassy swale were investigated at two small commercial areas in Dade County, Florida. One study area (airport) was located near the Miami International Airport and had a drainage area of about 10 acres overlying a sandy soil; the other study area (free zone) was located at the Miami International Free Trade Zone and had a drainage area of about 20 acres overlying limestone. The monitoring design for each study area consisted of seven sites and included water-quality sampling of the stormwater in the catch basin of the exfiltration trench, ground water from two wells 1 foot from the trench (trench wells), two wells 20 feet from the trench, and ground water from two wells at the swale from April 1985 through May 1986. Eleven water-quality variables (target variables) commonly found in high levels in urban stormwater runoff were used as tracers to estimate possible changes in ground-water quality that may have been caused by stormwater recharge. Comparison of the distribution of target variables indicated that the concentrations tended to be greater in the stormwater in the exfiltration trench than in water from the two wells 1 foot from the trench at both study areas. The concentration difference for several target variables was statistically significant at the 5-percent level. Lead, for example, had median concentrations of 23 and 4 micrograms per liter, respectively, in stormwater and water from the two trench wells at the airport study area, and 38 and 2 micrograms per liter, respectively, in stormwater and groundwater at the free zone. Similar reductions in concentrations between stormwater and water from the two trench wells were indicated for zinc at both study areas and also for nitrogen, phosphorus, and organic content at the free zone. This trend suggested that the exfiltration trench at both study areas may function as a partial trap for some chemical substances present in stormwater. A comparison of the distribution of the 11 target variables and major ionic composition in water from the two trench wells and the two wells 20 feet from the trench did not indicate a notable horizontal stratification at either study area. A vertical difference between 10 and 15 feet, however, was indicated at the free zone with major ions in greater concentrations at 15 feet. The vertical variability in groundwater near the trench at the free zone may have been the result of stormwater dilution in the upper (10-foot) zone. The ground-water quality at the swale was quite dissimilar to that near the exfiltration trench at both the airport and free zone study areas. Data indicated that the groundwater environment at both sales was anaerobic as evidenced by abundant ammonia nitrogen and iron and trace levels of sulfate. Anaerobic conditions at the swale may have been the result of poor drainage and high organic content of soils. Significant biochemical cycling in the ground water at the swales precluded any assessment of quality effects that may result from storm-water infiltration.

Florida↗
USGS1985

Quality of ground water used for public supply in Florida, 1983-84

From October 1983 through March 1984, a chemical sampling reconnaissance was made of ground water used for public supply for 91 communities throughout Florida. Public supply wells present an excellent network for collecting baseline water-quality information on the quality of ground water prior to any treatment because they are located throughout the State, are in the most populated areas, usually have continuous and often high pumpage, and have great health and economic significance. The reconnaissance was part of several project tasks sponsored by the Florida Department of Environmental Regulation to develop guidelines and data bases for use in the design and implementation of a statewide ground-water monitoring network as mandated by the recent enactment of Florida 's Water Quality Assurance Act of 1983. (USGS)

Open-File Report↗
USGS1985

Reconnaissance of selected organic contaminants in effluent and ground water at fifteen municipal wastewater treatment plants in Florida, 1983- 84

Results of a 1983-84 reconnaissance of 15 municipal wastewater treatment plants in Florida indicated that effluent from most of the plants contains trace concentrations of volatile organic compounds. Chloroform was detected in the effluent at 11 of the 15 plants and its common occurrence was likely the result of chlorination. The maximum concentration of chloroform detected in the effluent sampled was 120 micrograms/L. Detectable concentrations of selected organophosphorus insecticides were also common. For example, diazinon was detected in the effluent at 12 of the 15 plants with a maximum concentration of 1.5 micrograms/L. Organochlorine insecticides, primarily lindane, were detected in the effluent at 8 of the 15 plants with a maximum concentration of 1.0 micrograms/L. Volatile compounds, primarily chloroform, were detected in water from monitor wells at four plants and organophosphorus insecticides, primarily diazinon, were present in the groundwater at three treatment plants. Organochlorine insecticides were not detected in any samples from monitor wells. Based on the limited data available, this cursory reconaissance suggests that the organic contaminants commonly occurring in the effluent of many of the treatment plants are not transported into the local groundwater. (Author 's abstract)

Water-Resources Investigations Report↗
USGS1984

Quality of water recovered from a municipal effluent injection well in the Floridan aquifer system, Pompano Beach, Florida

Approximately 69 million gallons of backflow from an injection well used for the disposal of secondary treated municipal effluent in the Floridan aquifer system near Pompano Beach, Florida, was periodically sampled for inorganic quality from March 1975 through March 1977. Analyses of the backflow effluent showed a concomitant increase in dissolved solids and a change in ionic composition as a function of cumulative volume of backflow. Both the increase in dissolved solids and the change in major ionic composition were directly related to an estimated 6 to 7 percent mixing of the moderately saline water in the Florida aquifer system with the injected system with the injected effluent. Although an estimated 3.5 billion gallons of effluent was injected into the aquifer system during the 16-year operation of the Collier Manor treatment plant, only 65 to 70 million gallons was backflowed before the chloride concentration approached 250 milligrams per liter. (USGS)

Florida↗
USGS1983

Water-quality assessment of stormwater runoff from a heavily used urban highway bridge in Miami, Florida

Runoff from a heavily-traveled, 1.43-acre bridge section of Interstate-95 in Miami, Florida, was comprehensively monitored for both quality and quantity during five selected storms between November 1979 and May 1981. For most water-quality parameters, 6 to 11 samples were collected during each of the 5 runoff events. Concentrations of most parameters in the runoff were quite variable both during individual storm events and among the five storm events; however, the ranges in parameter concentration were about the same magnitude report for numerous other highway and urban drainages. Data were normalized to estimate the average, discharge-weighted parameter loads per storm per acre of bridge surface and results suggested that the most significant factor influencing stormwater loads was parameter concentration. Rainfall intensity and runoff volume, however, influenced rates of loading. The total number of antecedent dry days and traffic volume did not appear to be conspicously related to either runoff concentrations or loads. (USGS)

Florida↗
USGS1980

Chemical, physical, and radiological quality of selected public water supplies in Florida : January-May 1979

Verde Valley--an area of complex geology where the crust of the North American plate changes from unstable to stable--is in central Arizona in the transition zone between the Basin and Range and the Colorado Plateaus tectonic provinces. Volcanism and tectonism have been progressing northeastward along the transition zone for about 20 million years. The Verde Hot Springs area is the focal point of the intersection of three major lineaments. More than 100 water samples were collected from wells and springs in the valley, and temperatures of the potential geothermal resources were calculated using two geochemical methods or geothermometers--silica and Na-K-Ca geothermometers. Because of the high concentration of dissolved magnesium in the ground water, the silica geotemperatures are considered to be more reliable than the Na-K-Ca geotemperatures. The Camp Verde and Verde Hot Springs areas contain ground water that has quartz-silica geotemperatures of between 99 and 135C and chalcedony-silica geotemperatures of between 73 and 111C. The geochemical evidence to substantiate a geothermal resource in Verde Valley is not conclusive, and further work including test drilling, should be done to verify the silica geotemperatures given in the map. (Kosco-USGS)

Water-Resources Investigations Report↗
USGS1980

Chemical and physical characteristics of precipitation at selected sites in Florida

Infrequent sampling of precipitation in Florida has been conducted by the U.S. Geological Survey since 1965. A summary of the historical data from 24 sites throughout Florida indicate that the principal ionic composition of atmospheric precipitation samples is calcium-sodium and bicarbonate-chloride with an average specific conductance of 32 micromhos per centimeter at 25 C. Historically, much of the sampling focused on primary nutrients and selected trace elements. Historical data indicate that nitrogen and phosphorus concentrations averaged 1.1 and 0.1 milligrams per liter, respectively. The limited trace metal data indicate that motor-vehicle activity may have a significant impact on local precipitation quality. Lead, for example, was measured in concentrations of as much as 2,400 micrograms per liter in samples collected in a highly populated, commerical area in south Florida. Statistical testing indicated that most major inorganic constituents, primary nutrients, and trace metals were significantly differnet among the sampling sites. The pH data indicated a range of about 5.0 to 7.0, but only limited pH data were collected and analyzed at the historical sites in such a timely manner as to represent pH conditions of the atmospheric precipitation during active rainfall. A critical review of the historical data suggested that while they may reflect local atmospheric quality conditions they likely do not define baseline conditions from a regional perspective. The application of these data were generally limited regarding regional extrapolation due to lack of standardization of sampling techniques, variable methods of sample preservation, nonuniform sampling intervals, variable sample sizes, and different periods of record. (USGS)

Water-Resources Investigations Report↗
USGS1979

Chemical, physical, and radiological quality of selected public water supplies in Florida, November 1977-February 1978

Virtually all treated public water supplies sampled in Florida meet the National Interim Primary and Proposed Secondary Drinking Water Regulations. These findings are based on a water-quality reconnaissance of 129 treated public supplies throughout the State during the period November 1977 through February 1978. While primary drinking water regulation exceedences were infrequent, lead, selenium, and gross alpha radioactivity in a very few water supplies were above established maximum contaminant levels. Additionally, the secondary drinking water regulation parameters--dissolved solids , chloride, sulfate, iron, color, and pH--were occasionally detected in excess of the proposed Federal regulations. The secondary regulations, however, pertain mainly to the aesthetic quality of drinking water and not directly to public health aspects. (Woodard-USGS)

Water-Resources Investigations Report↗
USGS1978

Chemical and physical quality of selected public water supplies in Florida, August-September 1976

Results of a 1976 water-quality reconnaissance made by the U.S. Geological Survey indicated that, with few exceptions, all public water supplies in Florida are of high quality and meet the standards set forth in the National Interim Primary Drinking Water Regulations. Occasionally the concentrations of fluoride, turbidity, cadmium, chromium, and lead approximated, equaled, or exceeded maximum contaminant levels with exceedences occurring very infrequently. The pesticides 2,4-D and silvex, were detected in some public supplies throughout the State mainly in surface water. Although pesticides were not detected in concentrations approaching the maximum levels established in the regulations, their presence does signal that the activities of man are beginning to affect some water resources. (Woodard-USGS)

Florida↗
USGS1978

Water-quality assessment of runoff from a rural highway bridge near Tallahassee, Florida

Runoff from a rural highway bridge on U.S. 27 near Tallahassee, Florida, was found to have an insignificant water-quality loading impact on the Ochlockonee River. Potential annual-runoff loads on the bridge surface for virtually all constituents studied were less than one percent of those transported by the river at the study site. The loading rates for some parameters were significantly related to traffic counts, but the regression equations were limited to traffic ranges between 3,800 to 4,200 vehicles per day in 1977-78. Precipitation samples indicated that a significant percentage of the constituent loading to the bridge surface is from atmospheric deposition. (Woodard-USGS)

Florida↗
USGS1977

Methods for collection and analysis of aquatic biological and microbiological samples

Chapter A4 contains methods used by the U.S. Geological Survey to collect, preserve, and analyze waters to determine their biological and microbiological properties. Part 1 discusses biological sampling and sampling statistics. The statistical procedures are accompanied by examples. Part 2 consists of detailed descriptions of more than 45 individual methods, including those for bacteria, phytoplankton, zooplankton, seston, periphyton, macrophytes, benthic invertebrates, fish and other vertebrates, cellular contents, productivity, and bioassays. Each method is summarized, and the application, interferences, apparatus, reagents, collection, analysis, calculations, reporting of results, precision and references are given. Part 3 consists of a glossary. Part 4 is a list of taxonomic references.

Techniques of Water-Resources Investigations↗
USGS1976

Reconnaissance water sampling for radium-226 in central and northern Florida, December 1974-March 1976

Analyses of 115 water samples collected from December 1974 through March 1976 in eight Florida Counties indicated that 22 samples (19 percent) had radium-226 activities equal to or in excess of 3 piC/liter (picocuries per liter), the concentration limit recommended for drinking water by the U.S. Public Health Service. The maximum radium-226 activity was 90 piC/liter in water from a shallow well in Polk County. The sampling reconnaissance was generally limited to areas of active phosphate mining and areas of undisturbed phosphate deposits. Most of the sampling was from water wells. Thirteen surface-water samples were collected in the Peace River drainage basin. The maximum radium-226 detected in surface-water samples was 3.6 piC/liter in Little Charlie Creek at State Road 664A in Hardee County. (Woodard-USGS)

Florida↗