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At least 253 records · Page 14Linked to original sources
USGS1974

Sediment transport by streams draining into the Delaware Estuary

The quantity of sediment transported by streams draining into the Delaware estuary from Pennsylvania, New Jersey, and Delaware varies areally according to geology, physiography, and land use. Of the estimated total sediment load of 1.6 million tons entering the Delaware estuary annually, about 48 percent is contributed by the Delaware River main stem at Trenton, NJ; 34 percent by Pennsylvania tributaries; and 18 percent by New Jersey and Delaware tributaries.

Water Supply Paper↗
USGS2026

The Great Lakes Geologic Mapping Coalition—Working collaboratively to understand the geology of the Great Lakes Region

Introduction The Great Lakes Geologic Mapping Coalition (GLGMC), commonly referred to as the “Coalition,” is a partnership between the U.S. Geological Survey (USGS), the U.S. States of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin and the Canadian province of Ontario. The member States receive funding for geologic mapping work from the USGS National Cooperative Geologic Mapping Program (NCGMP), whereas Ontario participates as a nonfunded partner. The mission of the GLGMC is to produce three-dimensional (3D) geologic maps that depict unconsolidated sediments and near-surface bedrock in the Great Lakes region of North America. Geologic maps are the basis of most earth science investigations and help support resource exploration (energy, minerals, groundwater), natural hazard mitigation, infrastructure development, and land-use planning, all of which can be used to advance economic development and strengthen national security in the Great Lakes region. During the last few million years, the Great Lakes region has experienced repeated glacial advances and retreats, leaving behind extensive sediments, abundant natural resources, and widespread effects on the underlying bedrock geology (Swezey and others, 2022). Linked by shared histories of past glaciations, industrial agriculture, and legacy automotive, coal, steel, and manufacturing industries, the GLGMC member States collaborate to improve the understanding of the 3D distribution of the sediments overlying the region’s bedrock (fig. 1). Developing a comprehensive subsurface 3D framework of this glaciated terrain can provide earth science data to policymakers at all levels. These insights facilitate informed decisions on the exploration, use, and protection of vital resources, such as critical minerals, industrial materials, and aquifers, thereby supporting economic prosperity and the well-being of the citizens of this region. Since its inception in 1998, the Coalition has completed more than 100 geologic mapping projects across the Great Lakes region. Each project aims to deliver geologic maps, 3D datasets, and other information that improves understanding of the geology of the Great Lakes region, with an emphasis on economic and water resources. Key deliverables include 3D geologic maps and models typically portraying sediment thickness, often derived from top-of-bedrock and borehole data. These products are developed through a combination of fieldwork, subsurface modeling, and the collection and analysis of rock and sediment cores. To support Coalition goals, member States collaborate with scientists working on related STATEMAP, EDMAP, and FEDMAP projects. Coalition scientists also engage with Tribal Nations in the Great Lakes region to ensure that Tribal interests pertaining to Coalition work are addressed. Through this collaboration, the Coalition unites the efforts of State, Federal, and Tribal Nation stakeholders to advance geologic data production and enhance understanding of the geologic resources of the Great Lakes region.

Illinois, Indiana, Michigan, Minnesota, New York, ↗
USGS1967

Chemical quality of surface water in the Allegheny River basin, Pennsylvania and New York

The Allegheny River is the principal source of water to many industries and to communities in the upper Ohio River Valley. The river and its many tributaries pass through 19 counties in northwestern and western Pennsylvania. The population in these counties exceeds 3 million. A major user of the Allegheny River is the city of Pittsburgh, which has a population greater than The Allegheny River is as basic to the economy of the upper Ohio River Valley in western Pennsylvania as are the rich deposits of bituminous coal, gas, and oil that underlie the drainage basin. During the past 5 years many streams that flow into the Allegheny have been low flowing because of droughts affecting much of the eastern United States. Consequently, the concentration of solutes in some streams has been unusually high because of wastes from coal mines and oil wells. These and other water-quality problems in the Allegheny River drainage basin are affecting the economic future of some areas in western Pennsylvania. Because of environmental factors such as climate, geology, and land and water uses, surface-water quality varies considerably throughout the river basin. The natural quality of headwater streams, for example, is affected by saltwater wastes from petroleum production. One of the streams most affected is Kinzua Creek, which had 2,900 parts per million chloride in a sample taken at Westline on September 2, 1959. However, after such streams as the Conewango, Brokenstraw, Tionesta, Oil, and French Creeks merge with the Allegheny River, the dissolved-solids and chloride concentrations are reduced by dilution. Central segments of the main river receive water from the Clarion River, Redbank, Mahoning, and Crooked Creeks after they have crossed the coal fields of west-central Pennsylvania. At times, therefore, these streams carry coal-mine wastes that are acidic. The Kiskiminetas River, which crosses these coal fields, discharged sulfuric acid into the Allegheny at a rate of 299 tons a day during the 1962 water year (October 1, 1961, to September 30, 1962). Mine water affects the quality of the Allegheny River most noticeably in its lower part where large withdrawals are made by the Pittsburgh Water Company at Aspinwall and the Wilkinsburg-Penn Joint Water Authority at Nadine. At these places raw river water is chemically .treated in modern treatment plants to control such objectionable characteristics as acidity and excessive concentrations of iron and manganese. Dissolved-solids content in the river varies along its entire length. In its upper reaches the water of the Allegheny River is a sodium chloride type, and at low flow, the sodium chloride is more than half the dissolved solids. In its lower reaches the water is a calcium sulfate .type, and at low flow the calcium sulfate is more than half the dissolved solids. In middle segments of the river from Franklin to Kittanning, water is more dilute and of a mixed type. Many small and several larger streams in the upper basin--such as the Conewango, Brokenstraw, Kinzua, Tionesta, and French Creeks--support large populations of game-fish. Even in segments of the Clarion River, Mahoning, and Redbank Creeks, which are at times affected by coal-mine wastes, fish are present. Although different species withstand varying amounts of contaminants in water, the continued presence of the fish indicates that the water is relatively pure and suitable for recreation and many other uses.

Water Supply Paper↗
USGS2012

A benthic-macroinvertebrate index of biotic integrity and assessment of conditions in selected streams in Chester County, Pennsylvania, 1998-2009

The Stream Conditions of Chester County Biological Monitoring Network (Network) was established by the U.S. Geological Survey and the Chester County Water Resources Authority in 1969. Chester County encompasses 760 square miles in southeastern Pennsylvania and has a rapidly expanding population. Land-use change has occurred in response to this continual growth, as open space, agricultural lands, and wooded lands have been converted to residential and commercial lands. In 1998, the Network was modified to include 18 fixed-location sites and 9 flexible-location sites. Sites were sampled annually in the fall (October-November) during base-flow conditions for water chemistry, instream habitat, and benthic macroinvertebrates. A new set of 9 flexible-location sites was selected each year. From 1998 to 2009, 213 samples were collected from the 18 fixed-location sites and 107 samples were collected from the 84 flexible-location sites. Eighteen flexible-location sites were sampled more than once over the 12-year period; 66 sites were sampled only once. Benthic-macroinvertebrate data from samples collected during 1998-2009 were used to establish the Chester County Index of Biotic Integrity (CC-IBI). The CC-IBI was based on the methods and metrics outlined in the Pennsylvania Department of Environmental Protection's "A Benthic Index of Biotic Integrity for Wadeable Freestone Streams in Pennsylvania." The resulting CC-IBI consists of scores for benthic-macroinvertebrate samples collected from sites in the Network that related to reference conditions in Chester County. Mean CC-IBI scores for 18 fixed-location sites ranged from 37.21 to 88.92. Thirty-nine percent of the 213 samples collected at the 18 fixed-location sites had a CC-IBI score less than 50; 33 percent, 50 to 70; 28 percent, greater than 70. CC-IBI scores from the 107 flexible-location samples ranged from 23.48 to 99.96. Twenty-five percent of the 107 samples collected at the flexible-location sites had a CC-IBI score less than 50; 33 percent, 50 to 70; and 42 percent, greater than 70. Factors that were found to affect CC-IBI scores are nutrient concentrations, habitat conditions, and percent of wooded and urban land use. A positive relation was determined between mean CC-IBI scores and mean total habitat scores for the 18 fixed-location sites. CC-IBI scores were most strongly affected by stream bank vegetative protection, embeddedness, riparian zone width, and sediment deposition. The highest CC-IBI scores were associated with sites that had greater than 28 percent wooded-wetland-water land use, less than 5 percent urban land use, and no municipal wastewater discharges within 10 miles upstream from the sampling site. The lowest CC-IBI scores were associated with sites where urban land use was greater than 15 percent or a municipal wastewater discharge was within 10 miles upstream from the sampling reach. The Mann Kendall test for trends was used to determine trends in CC-IBI scores and concentrations of nitrate, orthophosphate, and chloride for the 18 fixed-location sites. A positive trend in CC-IBI was determined for six sites, and a negative trend was determined for one site. Positive trends in nitrate concentrations were determined for 4 of the 18 fixed-location sites, and a negative trend in orthophosphate concentrations was determined for 1 of the 18 fixed-location sites. Positive trends in chloride concentrations were determined for 16 of the 18 fixed-location sites.

Pennsylvania↗
USGS2001

Water-quality conditions during low flow in the lower Youghiogheny River basin, Pennsylvania, October 5-7, 1998

In October 1998, a chemical synoptic survey was conducted by the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, National Energy Technology Laboratory, in the Lower Youghiogheny River Basin in Pennsylvania to give a snapshot of present (1998) water quality during low-flow conditions. Water samples from 38 sites—12 mainstem sites, 22 tributaries, and 4 mine discharges that discharge directly to the Youghiogheny River—were used to identify sources of contaminants from mining operations. Specific conductance, water temperature, pH, and dissolved oxygen were measured in the field at each site and concentrations of major ions and trace elements were measured in the laboratory.z Unaccounted for gains and losses in streamflow were measured during the study. Unaccounted for losses in streamflow might be attributed to water loss through streambed fractures. Extensive mine tunnels are present in the basin and loss of water to these tunnels seems likely. Unaccounted for gains in streamflow may be from unmeasured tributaries or surface seeps, but most of the gains are suspected to come from artesian flow through fractures in the streambed from underground mine pools. Influent flows of rust-colored water were noted in some river sections. The pH values for all the samples collected during this survey were above 5.8, and most (33 of 38 samples) were above 7.0. Samples from the four mine-discharge sites also had pH values between 6.3 and 6.7. The lowest pH (5.8) was in a tributary, Galley Run. All 38 sampling sites had net alkalinity. The alkalinity load in the Youghiogheny River increased between Connellsville and McKeesport from 35 to 79 tons per day. Above Smithton, the measured alkalinity load in the Lower Youghiogheny River agreed well with the estimated alkalinity load. Below Smithton, measured alkalinity loads in the Lower Youghiogheny River are greater than calculated loads, resulting in unaccounted for gains in alkalinity. These gains are believed to be from seeps in the streambed. Approximately one-third of the load of total alkalinity in the Youghiogheny River at McKeesport is attributed to Sewickley Creek, which contributes 14 tons per day. Sulfate concentrations in the Youghiogheny River steadily increase from 33 milligrams per liter at Connellsville to 77 milligrams per liter near McKeesport. The measured concentrations of sulfate exceeded Pennsylvania water-quality standards at four tributary sites (Galley Run, Hickman Run, Sewickley Creek, and Gillespie Run) and all four mine-discharge sites but not at any main-stem sites. A large increase in sulfate load between West Newton and Sutersville can be attributed almost entirely to the contribution from Sewickley Creek (49 tons per day). Approximately 25 percent of the load measured between Connellsville and McKeesport is unaccounted for. These gains are believed to be from seeps in the streambed from underground mine pools. Similar patterns also were observed for loads of sodium, calcium, and magnesium. Unmeasured inputs from mine drainage are believed to be the source of these loads. Elevated concentrations (above background levels) of chemicals associated with drainage from coal-mining operations were measured in samples from tributaries, especially from Galley Run, Gillespie Run, and Sewickley Creek, and from the mine-discharge sites. The synoptic survey conducted for this study was successful in identifying generalized reaches of the Youghiogheny River where unaccounted for loads of constituents associated with mining activities are entering the river. However, the survey was not able to pinpoint the location of these loads. Remote-sensing techniques, such as thermal infrared imaging by the National Energy Technology Laboratory, could be useful for determining the precise locations of these inputs.

Water-Resources Investigations Report↗
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.

Pennsylvania↗
USGS2005

Water budgets for selected watersheds in the Delaware River basin, eastern Pennsylvania and western New Jersey

This pilot study, done by the U.S. Geological Survey in cooperation with the Delaware River Basin Commission, developed annual water budgets using available data for five watersheds in the Delaware River Basin with different degrees of urbanization and different geological settings. A basin water budget and a water-use budget were developed for each watershed. The basin water budget describes inputs to the watershed (precipitation and imported water), outputs of water from the watershed (streamflow, exported water, leakage, consumed water, and evapotranspiration), and changes in ground-water and surface-water storage. The water-use budget describes water withdrawals in the watershed (ground-water and surface-water withdrawals), discharges of water in the watershed (discharge to surface water and ground water), and movement of water of water into and out of the watershed (imports, exports, and consumed water). The water-budget equations developed for this study can be applied to any watershed in the Delaware River Basin. Data used to develop the water budgets were obtained from available long-term meteorological and hydrological data-collection stations and from water-use data collected by regulatory agencies. In the Coastal Plain watersheds, net ground-water loss from unconfined to confined aquifers was determined by using ground-water-flow-model simulations. Error in the water-budget terms is caused by missing data, poor or incomplete measurements, overestimated or underestimated quantities, measurement or reporting errors, and the use of point measurements, such as precipitation and water levels, to estimate an areal quantity, particularly if the watershed is hydrologically or geologically complex or the data-collection station is outside the watershed. The complexity of the water budgets increases with increasing watershed urbanization and interbasin transfer of water. In the Wissahickon Creek watershed, for example, some ground water is discharged to streams in the watershed, some is exported as wastewater, and some is exported for public supply. In addition, ground water withdrawn outside the watershed is imported for public supply or imported as wastewater for treatment and discharge in the watershed. A GIS analysis was necessary to quantify many of the water-budget components. The 89.9-square mile East Branch Brandywine Creek watershed in Pennsylvania is a rural watershed with reservoir storage that is underlain by fractured rock. Water budgets were developed for 1977-2001. Average annual precipitation, streamflow, and evapotranspiration were 46.89, 21.58, and 25.88 inches, respectively. Some water was imported (average of 0.68 inches) into the watershed for public-water supply and as wastewater for treatment and discharge; these imports resulted in a net gain of water to the watershed. More water was discharged to East Branch Brandywine Creek than was withdrawn from it; the net discharge resulted in an increase in streamflow. Most ground water was withdrawn (average of 0.25 inches) for public-water supply. Surface water was withdrawn (average of 0.58 inches) for public-water and industrial supply. Discharge of water by sewage-treatment plants and industries (average of 1.22 inches) and regulation by Marsh Creek Reservoir caused base flow to appear an average of 7.2 percent higher than it would have been without these additional sources. On average, 67 percent of the difference was caused by sewage-treatment-plant and industrial discharges, and 33 percent was caused by regulation of the Marsh Creek Reservoir. Water imports, withdrawals, and discharges have been increasing as the watershed becomes increasingly urbanized. The 64-square mile Wissahickon Creek watershed in Pennsylvania is an urban watershed underlain by fractured rock. Water budgets were developed for 1987-98. Average annual precipitation, streamflow, and evapotranspiration were 47.23, 22.24, and 23.12 inches, respectively. The watershed is highly u

Pennsylvania↗
USGS1987

Surface-water quality in Pequea Creek basin, Pennsylvania, 1977-79

A study of the Pequea Creek basin was conducted by the U.S. Geological Survey, in cooperation with the Susquehanna River Basin Commission and the EPA from February 1977 through March 1979. Pequea Creek drains an intensive agricultural area of 154 sq mi in southeastern Pennsylvania, and enters the Susquehanna River 30 mi north of the Chesapeake Bay. The study included measurement of streamflow and collection of water and bottom material samples from seven sites in the basin during selected base flows and storms. Water samples were collected daily at a site near the mouth of Pequea Creek, and analyzed for suspended sediment, nitrogen and phosphorus species, organic carbon, and pesticides. Some groundwater samples also were collected and analyzed for nitrate. Annual yields measured from the basin during the study period were 1,950 ton/sq mi for suspended sediment, 13.8 ton/sq mi for total nitrogen, and 1.8 ton/sq mi for phosphorus. These yields are five times higher than any previously measured in the Susquehanna River basin. The discharges of all constituents monitored increased with increasing flow, indicated that a large amount of material in the basin is available for transport to streams during storms. The large yields of nitrogen and phosphorus are probably caused by the intensive agriculture in the basin coupled with large applications of fertilizer and manure to farm fields. Chemical analyses of rainfall samples indicate that precipitation was not a significant source of nitrogen and phosphorus. Excluding nitrate, all constituents measured were transported mainly during storms. Nitrate concentrations during base flow were as high as 10 mg/L as N--the Environmental Protection Agency standard for domestic water supplies. Groundwater sampled from farm wells had nitrate concentrations up to 28 mg/L as N. The largest concentrations of herbicides detected in Pequea basin were for 2,4-D, atrazine, and simazine. The maximum concentrations observed during storms were 1.2, 24, and 5.4 micrograms/L, respectively. The insecticides chlordane and DDT had mean concentrations of 0.02 and 0.01 micrograms/L, respectively. Lindane, PCB, and heptachlor slightly exceed maximum limits during storms.

Pennsylvania↗
USGS2016

Spatial and temporal variation of stream chemistry associated with contrasting geology and land-use patterns in the Chesapeake Bay watershed—Summary of results from Smith Creek, Virginia; Upper Chester River, Maryland; Conewago Creek, Pennsylvania; and Difficult Run, Virginia, 2010–2013

Despite widespread and ongoing implementation of conservation practices throughout the Chesapeake Bay watershed, water quality continues to be degraded by excess sediment and nutrient inputs. While the Chesapeake Bay Program has developed and maintains a large-scale and long-term monitoring network to detect improvements in water quality throughout the watershed, fewer resources have been allocated for monitoring smaller watersheds, even though water-quality improvements that may result from the implementation of conservation practices are likely to be first detected at smaller watershed scales. In 2010, the U.S. Geological Survey partnered with the U.S. Environmental Protection Agency and the U.S. Department of Agriculture to initiate water-quality monitoring in four selected small watersheds that were targeted for increased implementation of conservation practices. Smith Creek watershed is an agricultural watershed in the Shenandoah Valley of Virginia that is dominated by cattle and poultry production, and the Upper Chester River watershed is an agricultural watershed on the Eastern Shore of Maryland that is dominated by row-cropping activities. The Conewago Creek watershed is an agricultural watershed in southeastern Pennsylvania that is characterized by mixed agricultural activities. The fourth watershed, Difficult Run, is a suburban watershed in northern Virginia that is dominated by medium density residential development. The objective of this study was to investigate spatial and temporal variations in water chemistry and suspended sediment in these four relatively small watersheds that represent a range of land-use patterns and underlying geology to (1) characterize current water-quality conditions in these watersheds, and (2) identify the dominant sources, sinks, and transport processes in each watershed. The general study design involved two components. The first included intensive routine water-quality monitoring at an existing streamgage within each study area (including continuous water-quality monitoring as well as discrete water-quality sampling) to develop a detailed understanding of the temporal and hydrologic variability in stream chemistry and sediment transport in each watershed. The second component involved extensive water-quality monitoring at various sites throughout each watershed to develop a detailed understanding of spatial patterns. Both components were used to improve understanding of sources and transport processes affecting stream chemistry, including nutrients and suspended sediments, and their implications for detecting long-term trends related to best management practices. This report summarizes the results of monitoring that was performed from April 2010 through September 2013. Individual Small Watershed Summaries Summaries for each of the four small watersheds are presented below. Each watershed has a more descriptive and detailed section in the report, but these summaries may be particularly useful for some watershed managers and stakeholders desiring slightly less technical detail. Smith Creek Smith Creek is a 105.39-mi 2 watershed within the Shenandoah Valley that drains to the North Fork Shenandoah River. The long-term Smith Creek base-flow index is 72.3 percent, indicating that on average, approximately 72 percent of Smith Creek flow was base flow, which suggests that Smith Creek streamflow is dominated by groundwater discharge rather than stormwater runoff. A series of cluster and principal components analyses demonstrated that the majority of the variability in Smith Creek water quality could be attributed to hydrologic and seasonal variability. Statistically significant positive correlations with flow were observed for turbidity, suspended sediments, total nitrogen, ammonium, orthophosphate, iron, total phosphorus, and the ratio of calcium to magnesium. Statistically significant inverse correlations with flow were observed for specific conductance, magnesium, δ 15 N of nitrate, pH, bicarbonate, calcium, and δ 18 O of nitrate. Of particular note, flow and nitrate were not statistically significantly correlated, likely because of the relatively complex concentration-discharge relationship observed in continuous and discrete datasets. Statistically significant seasonal patterns were observed for numerous water-quality constituents: water temperature, turbidity, orthophosphate, total phosphorus, suspended-sediment concentration, and silica were higher during the warm season, but pH, dissolved oxygen, and sulfate were higher during the cool season. Surrogate regression models were developed to compute sediment and nutrient loads in Smith Creek using the continuous water-quality monitors. The mean Smith Creek in-stream sediment load was approximately 6,900 tons per year, with nearly 90 percent of the sediment load over the 3-year study period contributed during the eight largest storm events during that period. The Smith Creek total phosphorus load was approximately 21,000 pounds of phosphorus per year, with the majority of the load contributed during stormflow periods, although a substantial phosphorus load still occurs during base-flow conditions. The Smith Creek total nitrogen load was approximately 400,000 pounds per year, with total nitrogen accumulation less dominated by stormflow contributions (as was the case for sediment and total phosphorus) and strongly affected by base-flow export of nitrogen from the basin. Extensive water-quality monitoring throughout the Smith Creek watershed revealed how the complex geology and hydrology interacted to result in variable water chemistry. During relatively dry and low base-flow periods, much of the discharge in Smith Creek was contributed by a single dominant spring—Lacey Spring. During wetter base-flow periods, the flows in Smith Creek were largely generated by a mixture of headwater springs and forested mountain tributaries with very different geochemical composition. The headwater springs generally issued from limestone bedrock and were characterized as having relatively high nitrate, specific conductance, calcium, and magnesium, as well as relatively low concentrations of phosphorus, ammonium, iron, and manganese. The undeveloped, high-gradient, forested mountain sites were generally characterized by low ionic strength waters with low nutrient concentrations. Nitrate isotope data from the limestone springs generally were consistent with manure-derived nitrogen sources (such as cattle and poultry), although the possibility of other mixed sources cannot be excluded. Nitrate isotope data from the undeveloped, high-gradient forested mountain sites were more consistent with nitrogen from undisturbed soils, atmospheric deposition, or nitrogen fixation. Regardless of the nitrogen source, oxygen isotope data indicate that the nitrate was largely a result of nitrification. Land-use data indicate that manure sources of nitrogen dominated watershed nitrogen inputs. Phosphorus sources were less well studied. The presence of a single point-source discharge near the town of New Market contributed the majority of the phosphorus to Smith Creek under base-flow conditions, but nonpoint sources of phosphorus dominated the loading to Smith Creek during stormflow periods. Implementation of conservation practices increased in the Smith Creek watershed during the study period, and even though a broad range of practice types was implemented, the most common practices included stream fencing (for cattle exclusion), the development of nutrient management plans, conservation crop rotation, and the planting of cover crops. While the implementation of these conservation practices is encouraging, results indicate small increases in nitrate concentrations at the streamgage over the last 29 years, concurrent with small decreases in nitrate fluxes. It will likely be years before the cumulative effect of these practices can be detected in the Smith Creek water quality, and the magnitude of the effect of these conservation practices detected in Smith Creek will depend largely on whether nutrient loading (of manure and commercial fertilizer) is reduced over time. Upper Chester River The Upper Chester River watershed includes the 36-square-mile (mi 2 ) watershed area around several nontidal tributaries that drain into the tidal Chester River. The streamgage is on Chesterville Branch, the largest nontidal tributary (approximately 6.12 mi 2 ) and is the site for continuous water-quality monitoring for this project. The base-flow index at Chesterville Branch is about 72 percent and indicates that, as in most of the Coastal Plain, groundwater is the greatest contributor to streamflow. As such, more than 90 percent of the nitrogen in the stream is in the form of nitrate from groundwater. Continuous and discrete data collected at Chesterville Branch show the effects of streamflow and season on water quality. Significantly positive correlations with flow were observed for ammonium, dissolved and total phosphorus, sediment, and turbidity as runoff carried these constituents from the land surface into Chesterville Branch. Other constituents that increased significantly with flow include potassium, sulfate, iron, and manganese, which are likely contributed from near-stream areas and ponds with high organic-matter content. Total nitrogen, pH, and specific conductance, along with chemical constituents associated with groundwater inputs including nitrate, calcium, ratio of calcium to magnesium, silica, bicarbonate, and sodium, were negatively correlated with flow because concentrations of these constituents were diluted by runoff. Seasonal differences in water chemistry, which are most likely related to increased biologic effects on the uptake and release of chemicals in the stream and near-stream areas, also were observed. Water temperature, orthophosphate, δ 15 N of nitrate, bicarbonate, sodium, and the ratio of sodium to chloride were higher during the warm season, and dissolved oxygen, total nitrogen, nitrate, magnesium, sulfate, and manganese were higher during the cool season. Surrogate-regression models developed by using continuous water-quality data showed that the annual sediment load for the 2013 water year was about 2,600 tons, with more than 90 percent of this sediment contributed during two storms. The total phosphorus load in 2013 was about 13,000 pounds with more than 90 percent contributed during the same two storms as sediment. The load of total nitrogen, 140,000 pounds, accumulated steadily throughout the 2013 water year as nitrate in groundwater continuously discharged into the stream. The same two large storms that contributed 90 percent of the suspended-sediment and total phosphorus load only contributed about 20 percent of the annual total nitrogen load. Extensive water-quality monitoring of stream base flow throughout the Upper Chester River watershed identified how differences in land use and hydrogeology affected water chemistry. In parts of the watershed with well-drained soil and thick sandy aquifer sediments, concentrations of nitrate and other chemicals associated with fertilizer and lime application increased in streams as agricultural land use increased. More than 90 percent of the nitrogen in streams from these areas was in the form of nitrate, and concentrations ranged from about 5 milligrams per liter (mg/L) to 8 mg/L as nitrogen in the two largest tributaries. Stream nitrate concentrations were about 1 mg/L as nitrogen where soils were more poorly drained, the surficial aquifer sediments were thinner, and forests and wetlands were more widespread than agriculture. Nitrate isotope data were consistent with inorganic fertilizers ± atmospheric deposition and N 2 fixation as sources of nitrogen, and with nitrification as the dominant nitrate-forming process. Nitrate reduction was indicated by elevated δ 15 N and δ 18 O values in some samples from streams draining watersheds with poorly drained soils. An analysis of land-use data and SPARROW modeling input data attributed almost 90 percent of the nitrogen sources in the Upper Chester River watershed to inorganic fertilizer and fixation of atmospheric nitrogen by legumes, which is in agreement with the isotopic characteristics of nitrate in this watershed. Local sources of manure are limited in this area. Total phosphorus concentrations during base flow ranged from below detection to about 0.2 mg/L. Stream phosphorus concentrations during base flow were generally lower than those measured during storms because most phosphorus transport likely occurs as phosphorus attached to sediment particles during runoff. Because manure is not widely used in this area, the major source of phosphorus is likely fertilizer. The implementation of conservation practices in the Upper Chester River watershed increased substantially during the study period, with a total implementation of 1,194 U.S. Department of Agriculture-compliant practices. The most frequently used practices were oriented towards nutrient and sediment control, including cover crops, nutrient management planning, conservation crop rotation, conservation tillage, and irrigation management. The current Chesapeake Bay model for this area predicts that implementation of best management practices should result in a 13-percent decrease in overall delivery of nitrogen to the Upper Chester River. Because most nitrogen travels through the groundwater system for years to decades before being discharged to streams, the time period of monitoring was not sufficient to see the effects of these practices on water quality. The magnitude of the effect that may eventually be detected will depend on the degree to which nitrate leaching into the groundwater system is reduced over time. Loadings of phosphorus and sediment are primarily transported during large runoff events and are difficult to control and analyze for trends because of their timing and episodic nature. Conewago Creek Conewago Creek has two primary monitoring locations—one near the middle of the 47-mi 2 watershed and the other near the outlet just upstream of the Susquehanna River. The base-flow index was 47.3 percent for 2012–2013, indicating that on average, approximately 53 percent of the streamflow in Conewago Creek exited the watershed as surface flow, which suggests that the stormwater runoff was somewhat greater than groundwater discharge (base flow). A series of cluster and principal components analyses demonstrated that the majority of the variability in the Conewago Creek water quality could be attributed to hydrologic and seasonal variability. Statistically significant positive correlations with flow were observed at both monitoring sites for ammonium, total phosphorus, orthophosphate, iron, and manganese; additionally, at the upstream monitoring station, total nitrogen demonstrated a statistically significant positive correlation with flow. Statistically significant inverse correlations with flow were observed at both sites for water temperature, specific conductance (at the downstream site only), sulfate, chloride, calcium, and magnesium. Statistically significant seasonal patterns were observed for several water-quality constituents. Water temperature, phosphorus (upstream site only), and orthophosphate were higher during the warm season, and nitrate and total nitrogen (upstream site only) were higher during the cool season. Surrogate regression models were developed to compute sediment and nutrient load in Conewago Creek by using the continuous water-quality monitors and water-quality samples. Conewago Creek sediment load was approximately 9,900 tons in 2012 and approximately 18,900 tons in 2013, with nearly 80 percent of the sediment load in 2013 contributed by the three largest storm events. Annual total nitrogen loads could not be estimated due to poor model performance. The addition of continued monitoring or a continuously recording nitrate sensor could improve estimates of total nitrogen loads. During 2012 and 2013, phosphorus loads in Conewago Creek were approximately 50,000 pounds in each year. Combining data from one high-flow synoptic sampling with the data from routine sampling revealed how the geology and hydrology interact to result in variable water chemistry throughout the Conewago Creek watershed. The areas above the upstream gage in the headwaters are generally underlain by forested non-carbonate bedrock and are characterized by relatively low nitrate, specific conductance, calcium, and magnesium, as well as relatively low concentrations of phosphorus, ammonium, iron, and manganese. The more developed, agricultural areas below the upstream site were generally characterized by higher ionic strength waters with higher nutrient and metal concentrations. An analysis of land-use data and SPAtially Referenced Regressions On Watershed (SPARROW) modeling data indicates that manure sources of nitrogen dominate the input of nitrogen to the watershed. Implementation of conservation practices increased in the Conewago Creek watershed during the study period, and while a broad range of practice types were implemented, the most common practices included residue and tillage management, cover crops, nutrient management, terracing, and stream fencing (for animal exclusion or bank restoration). While the implementation of these conservation practices is encouraging, the cumulative effects of these practices probably will not be detected in Conewago Creek water quality for several years. The magnitude of the effects of these conservation practices on water quality in Conewago Creek will depend largely on the extent to which nutrient loading (septic, manure, and commercial fertilizer) and sediment-producing activities are reduced over time. Difficult Run The Difficult Run watershed is a 57.82-mi 2 watershed that drains to the Potomac River. The long-term Difficult Run base-flow index (from 1936 to 2010) was 57.9, indicating that approximately 58 percent of streamflow exited the watershed as base flow and 42 percent as stormflow; however, with continued development and urbanization of the watershed, the base-flow index has decreased to 50 percent during the last 20 years. This base-flow index was less than those of the other watersheds evaluated in this study, likely because the Difficult Run watershed largely is underlain by crystalline piedmont metamorphic rocks and has a greater proportion of impervious urban land cover. A series of cluster and principal components analyses indicated that most of the variability in Difficult Run water quality could be attributed to hydrologic variability and seasonality. Statistically significant positive correlations with flow were observed for turbidity, dissolved oxygen, suspended sediments, ammonium, orthophosphate, iron, and total phosphorus. Statistically significant inverse correlations with flow were observed for water temperature, pH, specific conductance, bicarbonate, calcium, magnesium, nitrate, δ 15 N of nitrate, and silica. Statistically significant seasonal patterns were observed for numerous water-quality constituents: water temperature, ammonium, orthophosphate, and δ 15 N of nitrate were higher during the warm season, and dissolved oxygen, nitrate, and manganese were higher during the cool season. Surrogate regression models were developed to compute sediment and nutrient loading rates. The Difficult Run sediment load was approximately 8,000 tons per year, with greater than 95 percent of the sediment load in the 2013 water year contributed by the seven largest storm events. The total phosphorus load in Difficult Run was approximately 14,000 pounds of phosphorus per year, with the majority of the load contributed during stormflow periods. The total nitrogen load in Difficult Run is estimated to have been approximately 140,000 pounds per year, with total nitrogen accumulation less dominated by stormflow contributions than that of phosphorus and strongly affected by base-flow export of nitrogen from the basin. Extensive water-quality monitoring throughout the Difficult Run watershed revealed relatively uniform generation of flow per unit of watershed area, as well as spatial variation in water quality that is strongly related to land-use activities. Elevated nitrate concentrations were observed in a subset of monitoring sites that are inversely correlated with population density and positively correlated to the septic system density within each subwatershed. The majority of the elevated nitrate concentrations for these sites are hypothesized to be caused by nitrate leaching from septic systems, more so than homeowner fertilizer usage among these subwatersheds that have lower population densities than other parts of the watershed. Nitrate isotope data, temporal patterns in the water-quality data, mass-balance computations, and a separate land-use analysis all generally indicate that leachate from septic systems was the likely source of the elevated nitrate. Another group of water-quality sites have relatively low nitrogen concentrations, are located in areas that are served by city sewer lines, and have experienced stream restoration activities. A final group of sites drained the areas with the highest imperviousness and had strongly elevated specific conductance, chloride, and sodium, which were likely caused by a combination of road salting and other anthropogenic sources draining these urbanized areas in the watershed. A fourth group of sites represents a mixture of water sources and had water quality similar to that at the Difficult Run streamgage. Analysis of the nitrate isotope data generally indicates a broad range of composition indicative of mixed natural and anthropogenic nitrogen sources. Implementation of conservation practices increased in the Difficult Run watershed during the study period, and while a broad range of practice types was implemented, the most common practices included stream restoration. While the implementation of these conservation practices is encouraging, the cumulative effect of these practices probably will not be detected in Difficult Run water quality for several years.

Maryland, Pennsylvania, Virginia↗
USGS2014

Report of the committee on chemistry of natural waters, 1933–34

The personnel of this Committee during the past year, practically the same as during the previous year, has been as follows: C. S. Howard, Chairman—United States Geological Survey, Washington, D.C. L. C. Case—Gypsy Oil Company, Tulsa, Oklahoma. W. D. Collins—United States Geological Survey, Washington, D.C. H. F. Flynn—United States Engineer Office, 35 South Ninth Street, Philadelphia, Pennsylvania. W. P. Kelley—University of California, Riverside, California. Alfred C. Lane—Tufts College, Tufts College, Massachusetts. Augustus Locke—477 Mills Building, San Francisco, California. R. D. Leitch—United States Bureau of Mines, Pittsburgh, Pennsylvania. H. T. Logan—United States Bureau of Standards, Washington, D.C. Thomas S. Lovering—United States Geological Survey, Washington, D.C. Thomas E. Means—111 Sutter Street, San Francisco, California. F. B. Plummer—University of Texas, Austin, Texas. J. W. Sale—United States Food and Drug Administration, Washington, D.C. C S. Scofield—Bureau of Plant Industry, Department of Agriculture, Washington, D.C. Thomas G. Thompson—University of Washington, Seattle, Washington.

Eos, Transactions, American Geophysical Union↗
USGS1983

A reconnaissance geochemical survey of the Allegheny Front and Hickory Creek Roadless Areas, Allegheny National Forest, Warren County, Pennsylvania

A reconnaissance geochemical survey of the Allegheny Front and Hickory Creek Roadless Areas, Warren County, Pennsylvania, was made by members of the U.S. Geological Survey (USGS) to test for indistinct or unexposed mineral deposits that might be recognized by geochemical halos. Analyses using semiquantitative emission spectrography and atomic absorption for 32 elements were performed on 21 stream-sediment samples and 31 bedrock samples from the Allegheny Front tract, and on 23 stream-sediment samples and 6 bedrock samples from the Hickory Creek tract. Bedrock samples analyzed are primarily sandstone, siltstone and shale. Neither major chemical anomalies nor obviously anomalous chemical-element concentrations related to mineralized bedrock were indicated in the geochemical survey. Metallic mineral deposits were not identified in the study area during the survey, which is consistent with other studies reported in the literature for the surrounding region. The lithologic units exposed in the roadless areas do not commonly host metallic deposits in the surrounding region, and the probability is low that such deposits occur in the roadless areas.

Open-File Report↗