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Ronald A. Sloto

Publications and source records attributed to Ronald A. Sloto.

45 records · Page 3Linked to original sources
USGS1996

Geohydrology of the Stockton Formation and cross-contamination through open boreholes, Hatboro Borough and Warminster Township, Pennsylvania

The study area consists of a 9-square-mile area underlain by sedimentary rocks of the middle arkose member of the Stockton Formation of Upper Triassic age. In the Hatboro area, the Stockton Formation strikes approximately N. 65 degrees E. and dps approximately 9 degrees NW. The rocks are chiefly arkosic sandstone and siltstone. Rocks of the Stocton Formation form a complex, heterogeneous, multiaquifer system consisting of a series of gently dipping lithologic units with different hydraulic properties. Most ground water in the unweathered zone moves through a network of interconnecting secondary openigns-fractures, bedding plans, and joints. Ground water is unconfined in the shallower part of the aquifer and semiconfined or confined in the deeper part of the aquifer. Nearly all deep wells in the Stockton Formation are open to several water-bearing zones and are multiaquifer wells. Each water-bearing zone usually has a different hydraulic head. Where differences in hydraulic head exist between water-bearing zones, water in the well bore flows under nonpumping conditions in the direction of decreasing head. Determination of the potential for borehole flow was based on caliper, natural-gamma, single- point-resistance, fluid-resistivity, and (or) fluid-temperature logs that were run in 162 boreholes 31 to 655 feet deep. The direction and rate of borehole-fluid movement were determined in 83 boreholes by the bring-tracing method and in 10 boreholes by use of a heat-pulse flowmeter. Borehole flow was measurable in 65 of the 93 boreholes (70 percent). Fluid movement at rates up to 17 gallons per minute was measured. Downward flow was measured in 36 boreholes, and upward flow was measured in 23 boreholes, not including those boreholes in which two directions of flow were measured. Both upward and downward vertical flow was measured in six boreholes; these boreholes are 396 to 470 feet deep and were among the deepest boreholes logged. Fluid movement was upward in the upper part of the borehole and downward in the lower part of the borehole in two boreholes. Fluid movement wad downward in the upper part of the borehole and upward in the lower part of the borehole in three boreholes. Groung-water contamination by volatile organic compounds (VOC's) is widespread in the study area. Detectable concentrations of VOC's were present in water samples from 24 wells sampled in Hatboro Brough and in water samples for 10 of 14 wells (71 percent) samples in Warminster Township. Samples of borehole flow from nine boreholes in the industrial area of Hatboro were collected for laboratory analysis to estimate the quantity of VOC's in borehole flow. Downward flow was measured in all of these boreholes. Concentrations of TCE, TCA, and 1,1-DCE as great at 5,800, 1,400 and 260 micrograms per liter, respectively, show that some water moving downward in the aquifer through these open boreholes is highly contaminated and that open boreholes may contribute substantially to ground-water contamination. An estimated 14.7 gallons per year of VOC's were moving downward through the nine open boreholes sampled from the contaminated, upper part of the aquifer to the lower part, which is tapped by public supply wells. Borehole geophysical logs were used as a guide to design and construct monitor-well networks at three National Priorities List sites in the area. An open borehole was dirlled, and a suite of geophysical logs was run. Interpretation of geophysical logs enabled the identification of water-bearing zones that produce and receive water; these are zones that should not be connected. From the logs, discrete intervals to be monitored were selected. In the Stockton Formation, the same water-bearing zone may not be intersected in adjacent boreholes, especially if it is a vertical fracture with a diffident magnetic orientation than that of the adjacent boreholes. In most areas of the stockton Formation, depth of water-bearing zones in an are

Pennsylvania↗
USGS1996

Hydrogeology and ground-water quality of Valley Forge National Historical Park, Montgomery County, Pennsylvania

Valley Forge National Historical Park is just southwest of the Commodore Semiconductor Group (CSG) National Priorities List (Superfund) Site, a source of volatile organic compounds (VOC's) in ground water. The 7.5-square-mile study area includes the part of the park in Lower Providence and West Norriton Townships in Montgomery County, Pa., and surrounding vicinity. The park is underlain by sedimentary rocks of the Upper Triassic age stockton Formation. A potentiometric-surface map constructed from water levels measured in 59 wells shows a cone of depression, approximately 0.5 mile in diameter, centered near the CSG Site. The cone of depression is caused by the pumping of six public supply wells. A ground-water divide between the cone of depression and Valley Forge National Historical Park provides a hydraulic barrier to the flow of ground water and contaminants from the CSG Site to the park. If pumping in the cone of depression was to cease, water levels would recover, and the ground-water divide would shift to the north. A hydraulic gradient between the CSG Site and the Schuylkill River would be established, causing contaminated ground water to flow to the park. Water samples were collected from 12 wells within the park boundary and 9 wells between the park boundary and the ground-water divide to the north of the park. All water samples were analyzed for physical properties (field determinations), nutrients, common ions, metals and other trace constituents, and VOC's. Water samples from the 12 wells inside the park boundary also were analyzed for pesticides. Concentrations of inorganic constituents in the water samples did not exceed U.S. Environmental Protection Agency maximum contaminant levels. Very low concentrations of organic compounds were detected in some of the water samples. VOC's were detected in water from 76 percent of the wells sampled; the maximum concentration detected was 5.8 micrograms per liter of chloroform. The most commonly detected VOC was chloroform. The second most commonly detected compound was methyl tert-butyl ether (MTBE), which was detected in water from 24 percent of wells sampled. Several pesticides were detected in water samples collected from within the park boundaries.: chlordane, DDD, dieldrin, endrin, heptachlor epoxide, and simazine. Concentrations of the detected pesticides were 0.1 micrograms per liter or less and did not exceed U.S. Environmental Protection Agency maximum contaminant levels.

Water-Resources Investigations Report↗
USGS1995

Altitude and configuration of the potentiometric surface, Casey Village, Warminster and Upper Southampton townships, Bucks County, Pennsylvania, August 3, 1995

A map showing the potentiometric surface in Casey Village, Warminster and Upper Southampton Townships, Bucks County, was constructed from water levels measured on August 3, 1995. The potentiometric surface, measured in 17 wells screened between 18 and 64 feet below land surface, ranged from 321.99 to 344.80 feet above sea level. The potentiometric surface, measured in 12 wells screened between 48 and 108 feet below land surface, ranged from 321.95 to 337.50 feet above sea level.

Open-File Report↗
USGS1995

Geohydrology and vertical distribution of volatile organic compounds in ground water, Fischer and Porter Company Superfund Site, Warminster, Bucks County, Pennsylvania

The Fischer and Porter Company Superfund Site is underlain by sedimentary rocks of the Upper Triassic Stockton Formation, which consists of interbedded siltstone, very-fine grained to coarse-grained sandstone, and conglomerate in crudely defined, upward fining cycles. These rocks form a complex, heterogeneous, leaky, multiaquifer system comprised of a series of gently dipping lithologic units with different hydraulic properties. Ground water is unconfined in the shallower part of the aquifer and confined or semiconfined in the deeper part of the aquifer. Water levels measured in monitor well clusters and borehole-flow measurements made in open boreholes show a downward hydraulic head gradient at the site, caused in part by the pumping of nearby, deep public-supply wells and the Fischer and Porter treatment system extraction wells. Downward borehole flow was measured at rates up to 9 gallons per minute. Aquifer-isolation tests were run in the six boreholes to obtain depth-discrete specific-capacity and water-quality data. On the basis of specific-capacity data for 27 isolated intervals, specific capacity is not related to depth. Water levels in monitor wells at the Fischer and Porter Site are greatly affected by the pumping of nearby public-supply wells, as well as the pumping of the Fischer and Porter treatment system extraction wells. Pumping of the public-supply wells causes daily water-level fluctuations in wells at the site as great as 5.3 feet. The shutdown of the Fischer and Porter treatment system extraction wells caused a rise in water level in all wells screened in the intermediate and deep zones. The rise in water level was as great as 4.3 feet in the intermediate zone and as great as 5.9 feet in the deep zone. The direction of ground-water flow is toward the north in the shallow and intermediate zones and toward the west and west-southwest in the deep zone. Ground-water discharge probably is to the unnamed tributary to Pennypack Creek north and west of the site. Volatile organic compounds (VOC's) were detected in most depth-discrete water samples. No general trend of increasing or decreasing concentrations of VOC's with depth were observed, and none of the isolated intervals had highly elevated concentrations of VOC's. Observed fairly constant concentrations of VOC's with depth are the result of the downward head gradient and the former presence of open boreholes on the site. The downward head gradient and pumping of nearby, deep public-supply wells caused the vertical migration and outward movement of VOC's into the aquifer through former supply and monitor wells of open-hole construction in the main area of contamination.

Pennsylvania↗
USGS1994

Hydrogeology and ground-water quality of northern Bucks County, Pennsylvania

The 187-square mile study area is in the Triassic-Jurassic Newark Basin. Most of the area is underlain by sedimentary rocks of Upper Triassic age (74 percent) and intrusive diabase of Jurassic age (12 percent) and includes two southwest-northeast trending valleys underlain by carbonate and crystalline rock. Ground water in the sedimentary rocks of Triassic age moves through a network of interconnecting secondary openings fractures, bedding planes, and joints. The ground-water system consists of beds with a relatively high transmissivity separated by beds with a relatively low transmissivity that form a leaky, multiaquifer system. Ground water is unconfined in the shallower part of the aquifer and confined or semiconfined in the deeper part of the aquifer. Most deep wells are open to several water-bearing zones and are multiaquifer wells. The frequency of occurrence of water-bearing zones decreases with depth. Sixty-five percent of water-bearing zones for all hydrogeologic units are within 200 feet of land surface, and 85 percent are within 300 feet of land surface. On the basis of the median specific capacity of nondomestic wells, carbonate rocks, the Brunswick Group, and the Stockton Formation are the most productive hydrogeologic units. Carbonate rocks and the Stockton Formation have the highest median nondomestic well yields (156 and 120 gallons per minute, respectively) among the hydrogeologic units. Thirty-four percent of domestic wells drilled in diabase, 30 percent in the Lockatong Formation, and 21 percent in carbonate rock yield less than 5 gallons per minute. Average water budgets for the Cooks, Tinicum, Paunnacussing, and Mill Creek Basins weighted by drainage area were calculated for 1991-92. Average annual precipitation was 41.7 in. (inches); average annual evapotranspiration (ET) and other losses were 26.2 in. or 63 percent of precipitation; average annual streamflow was 15.9 in., or 38 percent of the average precipitation; and the average annual change in ground-water storage was a decrease of 0.3 in., or less than 1 percent of the average annual precipitation. Average estimated recharge for 1991-92 weighted by drainage area was 10.1 in. [0.485 (Mgal/d)/mi 2 (million gallons per day per square mile)]; this is equal to a recharge rate of 758 gallons per day per acre. Water budgets for the Tohickon Creek Basin were calculated for 1968-91 (prior to regulation of the stream by Lake Nockamixon). The average annual precipitation was 47.2 in.; average annual ET and other losses were 24.3 in., or 51 percent of the average annual precipitation; and annual streamflow was 22.6 in., or 48 percent of the average annual precipitation. Streamflow hydrographs for 1991-92 for Cooks, Tinicum, Paunnacussing, and Mill Creeks were separated into baseflow and surface-runoff components. Average annual ground-water discharge to streams weighted by drainage area was 8.4 in. [0.403 (Mgal/d)/mi 2 ], which was 20 percent of the average annual precipitation and 53 percent of the average annual streamflow. Average annual surface runoff weighted by drainage area was 7.4 in., which was 18 percent of the average annual precipitation and 47 percent of the average annual streamflow. Annual base flow for 1936-71 for Tohickon Creek ranged from 2.5 in. [0.12 (Mgal/d)/mi 2 ] in 1965 to 8.4 in. [0.40 (Mgal/d)/mi 2 ] in 1945. The median base flow was 5.3 in. [0.25 (Mgal/d)/mi 2 ]. Water from wells in the crystalline rocks has the lowest median pH (5.8), the lowest median specific conductance (139 microsiemens per centimeter), the lowest median alkalinity [16 mg/L (milligrams per liter) as CaCOg], and the highest dissolved oxygen concentration (9.0 mg/L) of the hydrogeologic units. Water from wells in carbonate rocks has the highest median pH (7.8) and the highest median alkalinity (195 mg/L as CaCO3) of the hydrogeologic units. Water from wells in the Lockatong Formation has the highest median specific conductance (428 microsiemens per centimeter) and the lowest dissolved oxygen concentration (0.8 mg/L) of the hydrogeologic units. Water from wells in crystalline rocks contains the lowest concentrations of total dissolved solids (TDS) of the hydrogeologic units. Water from the Lockatong Formation contains the highest concentration of TDS of the hydrogeologic units. Water from only 1 of 83 wells sampled exceeded the U.S. Environmental Protection Agency (USEPA) secondary maximum contaminant level (SMCL) for TDS; the well is in the Lockatong Formation. Five of 86 samples (6 percent) and 6 of 75 samples (8 percent) exceed the USEPA SMCL for iron and manganese, respectively. Nitrate is the most prevalent nitrogen species in ground water. The median nitrate concentration for all hydrogeologic units is 2.3 mg/L. Of 71 water samples from wells, no concentrations of nitrate exceed the USEPA maximum contaminant level. The median dissolved radon-222 activity was highest for water samples from wells in crystalline rock [3,600 pCi/L (picocuries per liter)] and lowest for water samples from wells in the Lockatong Formation (340 pCi/L) and diabase (350 pCi/L). Water samples for analysis for volatile organic compounds (VOC's) were collected from 34 wells in areas where the potential existed for the presence of VOC's in ground water. VOC's were detected in 23 percent of the 34 wells sampled. The most commonly detected compound was trichloroethylene (13 percent of sampled wells).

Pennsylvania↗
USGS1989

Selected ground-water data, Chester County, Pennsylvania

Hydrologic data for Chester County, Pennsylvania are given for 3,010 wells and 32 springs. Water levels are given for 48 observation wells measured monthly during 1936-86. Chemical analyses of ground water are given for major ions, physical properties, nutrients, metals and other trace constituents, volatile organic compounds, acid organic compounds, base-neutral organic compounds, organochlorine insecticides, polychlorinated biphenyls, polychlorinated napthalenes, organophosphorous insecticides, organic acid herbicides, triazine herbicides, other organic compounds, and radionuclides.

Pennsylvania↗
USGS1977

Ground-water resources of Chester County, Pennsylvania

Fifty gallons per minute (3 liters per second) or more may be obtained from wells in almost all parts of the county, but not at all locations. Adequate exploration to find fracture or solution openings is required. Five hundred gallons per minute (30 liters per second) or more may be obtained from some of the carbonate rocks. Linear features are visible on 1:1,000,000-to 1:24,000-scale aerial imagery. Many linear features, but not all, have geologic or hydrologic significance, and some may indicate fractured rock that might be tapped by wells. Dissolved-solids concentration of most ground water is less than 500 milligrams per liter. Chemical-quality problems are predominantly caused by acidity, iron and manganese, or nitrate. Base (ground-water) runoff during a near-average year, 1968, was about 420 million gallons per day (18 cubic meters per second).

Pennsylvania↗
USGS1976

Selected hydrologic data, Chester County, Pennsylvania

This report presents selected hydrologic data collected during a study of the ground-water resources of Chester County, Pennsylvania. The study was made during 1973-76 by the U. S. Geological Survey in cooperation with the Chester County Water Resources Authority. This report is intended to make the data conveniently available and to supplement an interpretive report that will be published separately.

Pennsylvania↗