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Research about Pennsylvania

Source-linked reports with geographic coverage including Pennsylvania.

At least 433 records · Page 24Linked to original sources
USGS1990

Fractionation of palladium and platinum in a Mesozoic diabase sheet, Gettysburg basin, Pennsyvania: Implications for mineral exploration

The York Haven diabase sheet displays clear-cut evidence of fractionation of Pd and Pt during differentiation of a high-Ti (about 1.1%) quartz-normative tholeiitic magma (York Haven type). At York Haven the sheet is about 750 m thick. It is characterized by abundant cumulus MgO-rich orthopyroxene (bronzite), and is markedly depleted in incompatible elements relative to the chilled margins. In contrast, at Reesers Summit, 16 km to the northwest, the sheet is about 500 m thick and consists of evolved rocks that have contents of incompatible elements two to three times greater than in the enclosing chilled margins. These evolved rocks represent complementary fractions to the cumulate rocks at York Haven. Mineralogic, petrologic and geochemical variations suggest considerable lateral migration and fractionation of the initial magma. Chilled margins of both sections have essentially the same Pd and Pt contents (10 ppb each) and similar Pd to Pt ratios (1.2). During differentiation, the cumulate rocks at York Haven were enriched in Pt and depleted in Pd, whereas at Reesers Summit, the low-MgO diabase and ferrogabbro zone were enriched in Pd relative to Pt. Anomalously high contents of Pd (to 165 ppb), Au (to 54 ppb), and Te (to 26 ppb) were found in an iron- (to 18%) and chlorine- (to 0.44%) rich ferrogabbro at Reesers Summit, suggesting possible late or post-magmatic enrichment of precious metals. Field relations, geochemical and petrographic data provide guides for further exploration for Pd and Pt in differentiated high-Ti quartz-normative diabase sheets. Based on present information, the most favorable sites for economic deposits are late-stage differentiates enriched in Fe and Cl. ?? 1990.

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USGS1990

Technique for estimating depths of 100-year floods in Pennsylvania

Techniques are developed for estimating 100-year flood depths in natural channels of unregulated Pennsylvania streams that drain less than 2,200 square miles. Equations and graphs are presented relating the depth of the 100-year flood above median stage and drainage area in five defined hydrologic areas in the State. Another graph defines the relation between drainage area and median depth of flow over the low point of riffles. Thus 100-year depths on riffles can be estimated by summing depth values derived from two simple relations.

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USGS1990

Effects of acidic precipitation on the water quality of streams in the Laurel Hill area, Somerset County, Pennsylvania, 1983-86

Five headwater streams in the Laurel Hill area in southwestern Pennsylvania were investigated from September 1983 through February 1986 to determine possible effects of acidic precipitation on water quality. Precipitation in the Laurel Hill area is among the most acidic in the Nation, with a mean volume-weighted pH of 4.06. Sulfate is the dominant acid-forming anion, averaging 3.6 milligrams per liter or about 50 kilograms per hectare in wet deposition alone. Nitrate averages about 2 milligrams per liter or 7 kilograms per hectare in the study area. Stream chemistry in the five streams is quite variable and apparently is influenced to a large degree by the bedrock geology and by small amounts of alkaline material in watershed soils. Three of the five streams with no or little acid-neutralizing capacity presently are devoid of fish because of low pH and elevated aluminum concentrations. Aluminum concentrations increase in the other two streams during rainfall and snowmelt despite comparatively higher base flow and acid-neutralizing capacities. Comparison of the chemistry of streamflow during 14 storm events at South Fork Bens Creek and North Fork Bens Creek reveals similar chemical responses when discharge suddenly increases. Concentrations of dissolved metals and sulfate increased during stormflow and snowmelt runoff, whereas concentrations of base cations, silica, and chloride decreased. Nitrate concentrations were not affected by rainfall runoff by tended to increase with snowmelt runoff.

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USGS1990

Geohydrology and simulation of ground-water flow in the carbonate rocks of the Valley Creek basin, eastern Chester County, Pennsylvania

Sixty-eight percent of the 22.6-square-mile Valley Creek basin is underlain by Cambrian and Ordovician limestone and dolomite. Ground water flows through a network of interconnected secondary openings; primary porosity is virtually nonexistent. Some of these openings have been enlarged by solution. Secondary porosity and permeability exhibit great spatial variability, and the yield and specific capacity of wells are highly variable. The number of water-bearing zones decreases with depth. Fifty percent of water-bearing zones are encountered within 100 feet of the land surface, and 81 percent are within 200 feet. Most ground-water flow in the Valley Creek basin is local and discharges to nearby streams. Ground-water discharge comprised an average of 76 percent of the flow of Valley Creek during 1983--87, including both natural ground- water discharge and quarry pumpage discharged to Valley Creek. Discharge from the Cedar Hollow quarry comprised 21 to 26 percent of the base flow of Valley Creek; the average was 23 percent. The average natural base flow of Valley Creek would be 8 percent lower if the quarry were not operating. Regional ground-water flow is to the northeast to the Schuylkill River. On the western side of the Valley Creek basin, the ground-water divide is 1/2 mile west of the surface-water divide. An estimated 0.75 million gallons per day of ground water flows from the adjacent West Valley Creek basn eastward into the Valley Creek basin. A ground-water divide is not present on the eastern side of the basin; the water table slopes gently eastward toward the Schuylkill River. On the northeaster side, an estimated 1.76 million gallons per day of ground water flows northeastward out of the basin to the Schuylkill River beneath the surface-water divide. On the southeaster side, an estimated 0.85 million gallons per day of ground water flows beneath the surface-water divide into the basin. Annual water budgets and an average water budget were calculated for 1983-87 for the 20.8-square-mile area bove the streamflow-gaging station. Annual precipitation for 1983-87 ranged from 40.61 to 56.55 inches and averaged 47.25 inches; annual streamflow ranged from 15.55 to 28.57 inches and averaged 22.31 inches; annual evapotranspiration ranged from 18.21 to 24.83 inches and averaged 22.90 inches; and annual recharge ranged from 15.89 to 26.84 inches and averaged 21.04 inches. The Valley Creek basin was modeled as a two-dimensional water-table aquifer. Recharge to, ground-water flow through, and discharge from the rocks of Chester valley were simulated. In order to include the natural hydrologic boundaries of the ground-water-flwo system, the 66.4-square-mile area between the Brandywine Creek and the Schuylkill River was modeled. The model was calibrated under stead-state conditions using avareage recharge and evapotranspiration rates. Aquifer hydraulic conductivity was estimated from specific-capacity and quifer-test data. The average (1983-87) annual water budget for hte Valley Creek basin was simualted. The effect of increased ground-water development on base flow and underflow was simulated by locating a hypothetical well field produceing 4 million gallons per day in different parts of the basin. Pumpage from a well field near surface-water divides would induce as much as an additional 1.41 inches per year of underflow from an adjacent surface-water basin. Pumpage from a well field near the center of the basin would affect base flow more than underflow. Increased seepage of ground water into quarries as a result of their expansion was simulated as increased withdrawal by pumping. A 100-percent increase in the pumping rate of the Cedar Hollow quarry, from 3.93 to 7.86 million gallons per day, owuld reduce the natural base flow of Valley Creek by 18 percent. However, the quarry pumpage would be discharged to Valley Creek, thereby increasing the base flow at the gaging station by

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USGS1990

A conceptual weather-type classification procedure for the Philadelphia, Pennsylvania, area

A simple method of weather-type classification, based on a conceptual model of pressure systems that pass through the Philadelphia, Pennsylvania, area, has been developed. The only inputs required for the procedure are daily mean wind direction and cloud cover, which are used to index the relative position of pressure systems and fronts to Philadelphia. Daily mean wind-direction and cloud-cover data recorded at Philadelphia, Pennsylvania, from January 1954 through August 1988 were used to categorize daily weather conditions. The conceptual weather types reflect changes in daily air and dew-point temperatures, and changes in monthly mean temperature and monthly and annual precipitation. The weather-type classification produced by using the conceptual model was similar to a classification produced by using a multivariate statistical classification procedure. Even though the conceptual weather types are derived from a small amount of data, they appear to account for the variability of daily weather patterns sufficiently to describe distinct weather conditions for use in environmental analyses of weather-sensitive processes.

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USGS1990

Base-flow-frequency characteristics of selected Pennsylvania streams

Streamflow hydrographs of 309 streamflow stations in Pennsylvania were analyzed by using three computer-assisted empirical methods--local-minimum , fixed-interval, and sliding-interval--to separate the ground-water and surface-runoff components. The 2-, 5-, 10-, and 25-year base-flow-recurrence intervals were determined for each station. The 50- and 100-year recurrence intervals were determined for stations with minimums of 25 and 50 years of record, respectively. All active and inactive continuous-recording Pennsylvania streamflow stations with 10 or more years of record through water year 1986 were analyzed. Stations on the Delaware River in New York and New Jersey also were included. Hydrograph analysis by computer provides consistency of results by removing the subjectivity inherent in manual analyses and considerably reduces the time required to make the analyses. Estimates of the 25-year base-flow-recurrence interval made by using the local-minimum technique, which gives the most conservative estimate, range from 0.069 to 0.888 million gallons per day per square mile. Base flows estimated by using the three computer-assisted techniques compared well with published base flows estimated by using manual methods for three studies in southeastern Pennsylvania. Examples of the effects of geology, climate, regulation, and urbanization on base flow are provided.

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USGS1990

Effectiveness of the addition of alkaline materials at surface coal mines in preventing or abating acid mine drainage--Part 2. Mine site case studies

The effectiveness of preventing or ameliorating acid mine drainage (AMD) through the application of alkaline additives is evaluated for eight surface coal mines in Pennsylvania. Many of the mine sites had overburden characteristics that made prediction of post‐mining water quality uncertain. Alkaline materials were applied at rates ranging from 42 to greater than 1,000 tons as calcium carbonate per acre. In addition, two sites that were mined and reclaimed without alkaline additives are included for comparative purposes. Overburden sulfur concentration and "neutralization potential" (NP) data for multiple strata at each mine site were used to compute the cumulative, mass‐weighted "maximum potential acidity" (MPA) and "net neutralization potential" (NNP = NP ‐ MPA) by using three different calculation methods. Post‐reclamation water‐quality data were used to compute the net alkalinity (= alkalinity ‐ acidity). The most conservative determination of NNP, whereby MPA is calculated by multiplying the total sulfur concentration, in weight percent, by 62.5 instead of 31.25, yielded the best agreement with net alkalinity (patching signs on NNP and net alkalinity). The error in prediction using each method was that the reclaimed overburden was computed to be alkaline overall (NNP > 0), but the post‐reclamation water was acid (net alkalinity < 0). In general, alkaline addition rates were probably insufficient to neutralize, or too late to prevent, acid production in the mine spoil. At six of the seven mine sites that had overburden with insufficient NP relative to MPA (NNP < 0), the addition of alkaline materials failed to create alkaline mine drainage; AMD was formed or persisted. A control site which also had insufficient alkaline material, but did not incorporate alkaline additives, generated severe AMD. Two sites that had substantial, natural alkaline overburden produced alkaline drainage. Although the addition rates appear to be inadequate, other factors, such as unequal distribution and exposure of the acid‐forming or neutralizing materials and hydrogeological variability, complicate the evaluation of relative effectiveness of using different alkaline materials and placement of the acid‐ or alkaline‐producing materials.

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USGS1989

Physical, chemical, and biological data for selected streams in Chester County, Pennsylvania, 1969-80

This report presents physical, chemical, and biological data collected at 50 sampling sites on selected streams in Chester County, Pennsylvania from 1969 to 1980. The physical data consist of air and water temperature, stream discharge, suspended sediment, pH, specific conductance, and dissolved oxygen. The chemical data consist of laboratory determinations of total nutrients, major ions, and trace metals. The biological data consist of total coliform, fecal coliform, and fecal streptococcus bacteriological analyses, and benthicmacroinvertebrate population analyses. Brillouin's diversity index, maximum diversity, minimum diversity, and evenness for each sample, and median and mean Brilloiuin's diversity index, standard deviation, and standard error of the mean were calculated for the benthic-macroinvertebrate data for each site.

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USGS1989

Water quality data for precipitation and storm runoff in Pennypack Creek Basin, Philadelphia, Pennsylvania

This report presents data on the chemistry of precipitation and storm runoff that were collected during 29 storms from July 1979 through November 1980, in an urban environment in the Pennypack Creek basin, Philadelphia, Pennsylvania. Daily mean and instantaneous stream discharge data were collected at two U.S. Geological Survey gaging stations. Water-quality data collected from these sites and from one storm-sewer sampling site included nutrients, chemical and biochemical oxygen demands, solids, metals, major anions, other constituents, and pH. Instantaneous loads of selected constituents were computed. Chemical oxygen demand, biochemical oxygen demand, sulfate, alkalinity, chloride, and dissolved solids generally were low in precipitation and runoff. During the November 5, 1980 storm at Pine Road, dissolved nitrate concentrations equaled or exceeded 10 milligrams per liter in 17 percent of the samples analyzed and dissolved ammonia nitrogen concentrations exceeded 2.5 milligrams per liter. Generally, a comparison of median concentration of copper, lead, or zinc in precipitation and runoff at the Tustin Street storm-sewer site showed that median concentrations in precipitation were greater than those in runoff.

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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.

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USGS1989

Surface-water quality in the West Branch Susquehanna River basin, Pennsylvania: An appraisal of areal and temporal variability from 1962 to 1982 in hydrologic accounting unit 020502

The West Branch Susquehanna River basin has a drainage area of 6,955 square miles in north-central Pennsylvania and comprises Hydrologic Accounting Unit 020502. A National Stream Quality Accounting Network (NASQAN) waterquality data collection site, maintained by the U.S. Geological Survey, is located on the river near its mouth at Lewisburg, Pennsylvania. Water-quality data are collected at numerous other sites throughout the basin by the Pennsylvania Department of Environmental Resources, Bureau of Water Quality Management. Data collected from the NASQAN site and the sites operated by the Pennsylvania Department of Environmental Resources from 1962 to 1982 were used to evaluate water-quality variability in the basin. The following objectives were addressed: (1) describe the surface-water quality upstream of the NASQAN site on an areal and temporal basis; (2) relate the water-quality variability, on both an areal and temporal basis, to general basin characteristics; and (3) assess the ability of the water-quality data collected at the NASQAN site to represent, on both an areal and temporal basis the water quality for Hydrologic Accounting Unit 020502 upstream from the site. Areally, the water quality varies considerably throughout the basin. Generally, the river was found to have moderately good water quality in the upper reaches, poor water quality in its middle reach, and good water quality near the mouth. Two tributaries, Moshannon Creek (median pH 3.9) and Bald Eagle Creek (median pH 7.8), had the most pronounced effect on the water quality of the river. Temporal trends were found in the concentrations of several of the constituents at most of the stations. Of the constituents analyzed, those which exhibited increasing or decreasing trends most frequently were pH, alkalinity, dissolved sulfate, total ammonia, and total nitrite plus nitrate. The largest trends were in the concentrations of total-recoverable aluminum, manganese, and zinc. Causes of areal variation were attributed to land use and geologic variations throughout the basin. Trends which indicated an improvement in water qualijty are believed to be caused by improvements in the treatment of acid mine drainage and wastewater. Trends which indicated degradation of water quality were generally found in areas where these types of treatment are not yet effective. The NASQAN site at Lewisburg was shown not to represent the water quality of the entire basin, either areally or temporally. It does, however, represent the water quality of the West Branch Susquehanna River at its mouth.

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