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At least 631 records · Page 35Linked to original sources
USGS2015

Bedrock geologic map of the Spring Valley, West Plains, and parts of the Piedmont and Poplar Bluff 30'x60' quadrangles, Missouri, including the upper Current River and Eleven Point River drainage basins

This map covers the drainage basins of the upper Current River and the Eleven Point River in the Ozark Plateaus physiographic province of southeastern Missouri. The two surface drainage basins are contiguous in their headwaters regions, but are separated in their lower reaches by the lower Black River basin in the southeast corner of the map area. Numerous dye-trace studies demonstrate that in the contiguous headwaters areas, groundwater flows from the Eleven Point River basin into the Current River basin. Much of the groundwater discharge of the Eleven Point River basin emanates from Big Spring, located on the Current River. This geologic map and cross sections were produced to help fulfill a need to understand the geologic framework of the region in which this subsurface flow occurs. The map includes all of the Ozark National Scenic Riverways, a national park created by an Act of Congress in 1964 to protect 134 miles of the Current and Jacks Fork Rivers in south-central Missouri. Located within the park are numerous large springs, including Big Spring, the largest spring in Missouri and one of the ten largest springs in the world. Also within the map area is Greer Spring, which is the main source of the Eleven Point River. Greer Spring is the largest spring on National Forest land in the United States. During flood, flow from Greer Spring is almost as large, volumetrically, as that from Big Spring. The Wild and Scenic Rivers Act in 1968 established a 44-mile section of the Eleven Point River as the Eleven Point National Scenic River, which is entirely within the boundaries of this map. Potentially economic mineral resources are present in the subsurface in the map area. Exploration drill-hole data indicate that anomalously high concentrations of base-metal sulfides locally occur within the Cambrian Bonneterre Formation. The geologic setting of these anomalous concentrations is similar to that found in the Viburnum Trend, part of the largest lead-mining district in the world. The southernmost part of the Viburnum Trend extends into the northern part of the map area and is exploited by the Sweetwater Mine. Undeveloped and potentially economic occurrences of base metals are known also beneath Blair Creek, a tributary to the Current River in the north-central part of the map area.

Missouri↗
USGS1993

Structure of Crater Flat and Yucca Mountain, Southeastern Nevada, as inferred from gravity data

Existing gravity data in the vicinity of Yucca Mountain and Crater Flat have been examined to determine if these data support only the caldera model or if they support other geologic models such as for a high-angle graben or detachment fault. The west to east isostatic gravity profile reduced for a density of 2.0 g/cm3 shows a gravity low of about 20 mGal centered only 2 km from the eastern edge of Crater Flat relative to a gravity high over the eastern boundary of Yucca Mountain. In the western part of Crater Flat, isostatic anomalies rise about 50 mGal across the flat, reaching a maximum gradient of 9 mGal/km about 3 km east of the Bare Mountain range-front fault. Computer modeling of these data indicate that a model that consists of a detachment fault that dips to the west at 12?? under Yucca Mountain and intersects a 27?? east-dipping Bare Mountain fault fits the observed gravity data generally as well as the caldera model.

Conference Paper↗
USGS2019

Effects of urban multi-stressors on three stream biotic assemblages

During 2014, the U.S. Geological Survey (USGS) National Water-Quality Assessment(NAWQA) project assessed stream quality in 75 streams across an urban disturbance gradient within the Piedmont ecoregion of southeastern United States. Our objectives were to identify primary instream stressors affecting algal, macroinvertebrate and fish assemblages in wadeable streams. Biotic communities were surveyed once at each site, and various instream stressors were measured during a 4-week index period preceding the ecological sampling. The measured stressors included nutrients; contaminants in water, passive samplers, and sediment; instream habitat; and flow variability. All nine boosted regression tree models – three for each of algae, invertebrates, and fish – had cross-validation R 2 (CV R 2 ) values of 0.41 or above, and an invertebrate model had the highest CV R 2 of 0.65. At least one contaminant metric was important in every model, and minimum daytime dissolved oxygen (DO), nutrients, and flow alteration were important explanatory variables in many of the models. Physical habitat metrics such as sediment substrate were only moderately important. Flow alteration metrics were useful factors in eight of the nine models. Total phosphorus, acetanilide herbicides and flow (time since last peak) were important in all three algal models, whereas insecticide metrics (especially those representing fipronil and imidacloprid) were dominant in the invertebrate models. DO values below approximately 7 mg/L corresponded to a strong decrease in sensitive taxa or an increase in tolerant taxa. DO also showed strong interactions with other variables, particularly contaminants and sediment, where the combined effect of low DO and elevated contaminants increased the impact on the biota more than each variable individually. Contaminants and flow alteration were strongly correlated to urbanization, indicating the importance of urbanization to ecological stream condition in the region.

Science of the Total Environment↗
USGS2000

Nutrient, suspended-sediment, and total suspended-solids data for surface water in the Great Salt Lake basins study unit, Utah, Idaho, and Wyoming, 1980-95

Selected nitrogen and phosphorus (nutrient), suspended-sediment and total suspended-solids surface-water data were compiled from January 1980 through December 1995 within the Great Salt Lake Basins National Water-Quality Assessment study unit, which extends from southeastern Idaho to west-central Utah and from Great Salt Lake to the Wasatch and western Uinta Mountains. The data were retrieved from the U.S. Geological Survey National Water Information System and the State of Utah, Department of Environmental Quality, Division of Water Quality database. The Division of Water Quality database includes data that are submitted to the U.S. Environmental Protection Agency STOrage and RETrieval system. Water-quality data included in this report were selected for surface-water sites (rivers, streams, and canals) that had three or more nutrient, suspended-sediment, or total suspended-solids analyses. Also, 33 percent or more of the measurements at a site had to include discharge, and, for non-U.S. Geological Survey sites, there had to be 2 or more years of data. Ancillary data for parameters such as water temperature, pH, specific conductance, streamflow (discharge), dissolved oxygen, biochemical oxygen demand, alkalinity, and turbidity also were compiled, as available. The compiled nutrient database contains 13,511 samples from 191 selected sites. The compiled suspended-sediment and total suspended-solids database contains 11,642 samples from 142 selected sites. For the nutrient database, the median (50th percentile) sample period for individual sites is 6 years, and the 75th percentile is 14 years. The median number of samples per site is 52 and the 75th percentile is 110 samples. For the suspended-sediment and total suspended-solids database, the median sample period for individual sites is 9 years, and the 75th percentile is 14 years. The median number of samples per site is 76 and the 75th percentile is 120 samples. The compiled historical data are being used in the basinwide sampling strategy to characterize the broad-scale geographic and seasonal water-quality conditions in relation to major contaminant sources and background conditions. Data for this report are stored on a compact disc.

Idaho, Utah, Wyoming↗
USGS1958

Borate deposits of the Mojave Region, California

Output of the United States borate producers reached approximately 1,000,000 tons in 1957, nearly four times the average annual production of 1941-45. Increasing consumption for long-established uses and several new ones accounts for the rise; further rise, for new uses such as high energy fuels, lies ahead. Among known borate deposits, the largest are at Searles Lake and Kramer, which supply 90 percent of the world's recorded production. The Kramer ore body, which is very large, consists of remarkably pure sodium borates in Tertiary lake beds. At Searles Lake, also large, the borax is produced from brines pumped out of salt layers which are the residue of a dessicated Pleistocene lake. Prospecting for borates is now more active than it has been for years. The best prospecting ground is in the alluvial-covered basins of western Nevada and particularly southeastern California, in concealed sections of Tertiary continental sediments. Several playas or salt flats that resemble Searles Lake were test-drilled for the U. S. Geological Survey by a contractor but the holes encountered no borates. Drill holes near Kramer, however, encountered a deposit of colemanite in lake beds.

California, Nevada↗
USGS1996

Hydrology of central Florida lakes, a primer

Lakes are among the most valued natural resources of central Florida. The landscape of central Florida is riddled with lakes—when viewed from the air it almost seems there is more water than land. Florida has more naturally formed lakes than other southeastern States, where many lakes are manmade, created by building darns across streams. The abundance of lakes on the Florida peninsula is a result of the geology and geologic history of the State. An estimated 7,800 lakes in Florida are greater than 1 acre in surface area. Of these, 35 percent are located in just four counties (fig. 1): Lake, Orange, Osceola, and Polk (Hughes, 1974b). Lakes add to the aesthetic and commercial value of the area and are used by many residents and visitors for fishing, boating, swimming, and other types of outdoor recreation. Lakes also are used for other purposes, such as irrigation, flood control, water supply, and navigation.

Florida↗
USGS2004

Water quality, hydrology, and the effects of changes in phosphorus loading to Pike Lake, Washington County, Wisconsin, with special emphasis on inlet-to-outlet short-circuiting

Pike Lake is a 459-acre, mesotrophic to eutrophic dimictic lake in southeastern Wisconsin. Because of concern over degrading water quality in the lake associated with further development in its watershed, a study was conducted by the U.S. Geological Survey from 1998 to 2000 to describe the water quality and hydrology of the lake, quantify sources of phosphorus including the effects of short-circuiting of inflows, and determine how changes in phosphorus loading should affect the water quality of the lake. Measuring all significant water and phosphorus sources and estimating lesser sources was the method used to construct detailed water and phosphorus budgets. The Rubicon River, ungaged near-lake surface inflow, precipitation, and ground water provide 55, 20, 17, and 7 percent of the total inflow, respectively. Water leaves the lake through the Rubicon River outlet (87 percent) or by evaporation (13 percent). Total input of phosphorus to the lake was about 3,500 pounds in 1999 and 2,400 pounds in 2000. About 80 percent of the phosphorus was from the Rubicon River, about half of which came from the watershed and half from a waste-water treatment plant in Slinger, Wisconsin. Inlet-to-outlet short-circuiting of phosphorus is facilitated by a meandering segment of the Rubicon River channel through a marsh at the north end of the lake. It is estimated that 77 percent of phosphorus from the Rubicon River in monitoring year 1999 and 65 percent in monitoring year 2000 was short-circuited to the outlet without entering the main body of the lake. Simulations using water-quality models within the Wisconsin Lake Model Suite (WiLMS) indicated Pike Lake's response to 13 different phosphorus-loading scenarios. These scenarios included a base 'normal' year (2000) for which lake water quality and loading were known, six different percentage increases or decreases in phosphorus loading from controllable sources, and six different loading scenarios corresponding to specific management actions. Model simulations indicate that a 50-percent reduction in controllable loading sources would be needed to achieve a mesotrophic classification with respect to phosphorus, chlorophyll a, and Secchi depth (an index of water clarity). Model simulations indicated that short-circuiting of phosphorus from the inlet to the outlet was the main reason the water quality of the lake is good relative to the amount of loading from the Rubicon River and that changes in the percentage of inlet-to-outlet short-circuiting have a significant influence on the water quality of the lake.

Wisconsin↗
USGS1995

Environmental and hydrologic setting of the Ozark Plateaus study unit, Arkansas, Kansas, Missouri, and Oklahoma

The environmental and hydrologic setting of the Ozark Plateaus National Water-Quality Assessment (NAWQA) study unit and the factors that affect water quality are described in this report. The primary natural and cultural features that affect water- quality characteristics and the potential for future water-quality problems are described. These environmental features include climate, physio- graphy, geology, soils, population, land use, water use, and surface- and ground-water flow systems. The study-unit area is approximately 47,600 square miles and includes most of the Ozark Plateaus Province and parts of the adjacent Osage Plains and Mississippi Alluvial Plain in parts of Arkansas, Kansas, Missouri, and Oklahoma. The geology is characterized by basement igneous rocks overlain by a thick sequence of dolomites, limestones, sandstones, and shales of Paleozoic age. Land use in the study unit is predominantly pasture and forest in the southeastern part, and pasture and cropland in the northwestern part. All or part of the White, Neosho-lllinois, Osage, Gasconade, Meramec, St. Francis, and Black River Basins are within the study unit. Streams in the Boston Mountains contain the least mineralized water, and those in the Osage Plains contain the most mineralized water. The study unit contains eight hydrogeologic units including three major aquifers--the Springfield Plateau, Ozark, and St. Francois aquifers. Streams and aquifers in the study unit generally contain calcium or calcium-magnesium bicarbonate waters. Ground- and surface-water interactions are greatest in the Salem and Springfield Plateaus and least in the Boston Mountains and Osage Plains. Geology, land use, and population probably are the most important environmental factors that affect water quality.

Water-Resources Investigations Report↗
USGS2000

Naturally occurring radionuclides in the ground water of southeastern Pennsylvania

Naturally occurring radionuclides in the ground water of southeastern Pennsylvania may pose a health hazard to some residents, especially those drinking water from wells drilled in the Chickies Quartzite. Water from 46 percent of wells sampled in the Chickies Quartzite and 7 percent of wells sampled in other geologic formations exceeded the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) for total radium. Radon-222 may pose a health problem for homeowners by contributing to indoor air radon-222 levels. The radon-222 activity of water from 89 percent of sampled wells exceeded 300 pCi/L (picocuries per liter), the proposed USEPA MCL, and water from 16 percent of sampled wells exceeded 4,000 pCi/L. Uranium does not appear to be present in elevated concentrations in ground water in southeastern Pennsylvania.

Pennsylvania↗
USGS1992

Selected papers in the applied computer sciences 1992

This compilation of short papers reports on technical advances in the applied computer sciences. The papers describe computer applications in support of earth science investigations and research. This is the third volume in the series "Selected Papers in the Applied Computer Sciences." Listed below are the topics addressed in the compilation: Integration of geographic information systems and expert systems for resource management, Visualization of topography using digital image processing, Development of a ground-water data base for the southeastern Uited States using a geographic information system, Integration and aggregation of stream-drainage data using a geographic information system, Procedures used in production of digital geologic coverage using compact disc read-only memory (CD-ROM) technology, and Automated methods for producing a technical publication on estimated water use in the United States.

Bulletin↗
USGS2010

Occurrence and distribution of dissolved solids, selenium, and uranium in groundwater and surface water in the Arkansas River Basin from the headwaters to Coolidge, Kansas, 1970-2009

In 2007, the U.S. Geological Survey (USGS), in cooperation with City of Aurora, Colorado Springs Utilities, Colorado Water Conservation Board, Lower Arkansas Valley Water Conservancy District, Pueblo Board of Water Works, Southeastern Colorado Water Activity Enterprise, Southeastern Colorado Water Conservancy District, and Upper Arkansas Water Conservancy District began a retrospective evaluation to characterize the occurrence and distribution of dissolved-solids (DS), selenium, and uranium concentrations in groundwater and surface water in the Arkansas River Basin based on available water-quality data collected by several agencies. This report summarizes and characterizes available DS, dissolved-selenium, and dissolved-uranium concentrations in groundwater and surface water for 1970-2009 and describes DS, dissolved-selenium, and dissolved-uranium loads in surface water along the main-stem Arkansas River and selected tributary and diversion sites from the headwaters near Leadville, Colorado, to the USGS 07137500 Arkansas River near Coolidge, Kansas (Ark Coolidge), streamgage, a drainage area of 25,410 square miles. Dissolved-solids concentrations varied spatially in groundwater and surface water in the Arkansas River Basin. Dissolved-solids concentrations in groundwater from Quaternary alluvial, glacial drift, and wind-laid deposits (HSU 1) increased downgradient with median values of about 220 mg/L in the Upper Arkansas subbasin (Arkansas River Basin from the headwaters to Pueblo Reservoir) to about 3,400 mg/L in the Lower Arkansas subbasin (Arkansas River Basin from John Martin Reservoir to Ark Coolidge). Dissolved-solids concentrations in the Arkansas River also increased substantially in the downstream direction between the USGS 07086000 Arkansas River at Granite, Colorado (Ark Granite), and Ark Coolidge streamgages. Based on periodic data collected from 1976-2007, median DS concentrations in the Arkansas River ranged from about 64 mg/L at Ark Granite to about 4,060 mg/L at Ark Coolidge representing over a 6,000 percent increase in median DS concentrations. Temporal variations in specific conductance values (which are directly related to DS concentrations) and seasonal variations in DS concentrations and loads were investigated at selected sites in the Arkansas River from Ark Granite to Ark Coolidge. Analyses indicated that, for the most part, specific conductance values (surrogate for DS concentrations) have remained relatively constant or have decreased in the Arkansas River since about 1970. Dissolved-solids concentrations in the Arkansas River were higher during the nonirrigation season (November-February) than during the irrigation season (March-October). Average annual DS loads, however, were higher during the irrigation season than during the nonirrigation season. Average annual DS loads during the irrigation season were at least two times and as much as 23 times higher than average annual DS loads during the nonirrigation season with the largest differences occurring at sites located downstream from the two main-stem reservoirs at USGS 07099400 Arkansas River above Pueblo, Colorado (Ark Pueblo), (which is below Pueblo Reservoir) and USGS 07130500 Arkansas River below John Martin Reservoir, Colorado (Ark below JMR). View report for unabridged abstract.

Scientific Investigations Report↗
USGS2000

Environmental Setting and Effects on Water Quality in the Great and Little Miami River Basins, Ohio and Indiana

The Great and Little Miami River Basins drain approximately 7,354 square miles in southwestern Ohio and southeastern Indiana and are included in the more than 50 major river basins and aquifer systems selected for water-quality assessment as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Principal streams include the Great and Little Miami Rivers in Ohio and the Whitewater River in Indiana. The Great and Little Miami River Basins are almost entirely within the Till Plains section of the Central Lowland physiographic province and have a humid continental climate, characterized by well-defined summer and winter seasons. With the exception of a few areas near the Ohio River, Pleistocene glacial deposits, which are predominantly till, overlie lower Paleozoic limestone, dolomite, and shale bedrock. The principal aquifer is a complex buried-valley system of sand and gravel aquifers capable of supporting sustained well yields exceeding 1,000 gallons per minute. Designated by the U.S. Environmental Protection Agency as a sole-source aquifer, the Buried-Valley Aquifer System is the principal source of drinking water for 1.6 million people in the basins and is the dominant source of water for southwestern Ohio. Water use in the Great and Little Miami River Basins averaged 745 million gallons per day in 1995. Of this amount, 48 percent was supplied by surface water (including the Ohio River) and 52 percent was supplied by ground water. Land-use and waste-management practices influence the quality of water found in streams and aquifers in the Great and Little Miami River Basins. Land use is approximately 79 percent agriculture, 13 percent urban (residential, industrial, and commercial), and 7 percent forest. An estimated 2.8 million people live in the Great and Little Miami River Basins; major urban areas include Cincinnati and Dayton, Ohio. Fertilizers and pesticides associated with agricultural activity, discharges from municipal and industrial wastewater-treatment and thermoelectric plants, urban runoff, and disposal of solid and hazardous wastes contribute contaminants to surface water and ground water throughout the study area. Surface water and ground water in the Great and Little Miami River Basins are classified as very hard, calcium-magnesiumbicarbonate waters. The major-ion composition and hardness of surface water and ground water reflect extensive contact with the carbonate-rich soils, glacial sediments, and limestone or dolomite bedrock. Dieldrin, endrin, endosulfan II, and lindane are the most commonly reported organochlorine pesticides in streams draining the Great and Little Miami River Basins. Peak concentrations of the herbicides atrazine and metolachlor in streams commonly are associated with post-application runoff events. Nitrate concentrations in surface water average 3 to 4 mg/L (milligrams per liter) in the larger streams and also show strong seasonal variations related to application periods and runoff events. Ambient iron concentrations in ground water pumped from aquifers in the Great and Little Miami River Basins often exceed the U.S. Environmental Protection Agency Secondary Maximum Contaminant Level (300 micrograms per liter). Chloride concentrations are below aesthetic drinking-water guidelines (250 mg/L), except in ground water pumped from low-yielding Ordovician shale; chloride concentrations in sodium-chloriderich ground water pumped from the shale bedrock can exceed 1,000 mg/L. Some of the highest average nitrate concentrations in ground water in Ohio and Indiana are found in wells completed in the buried-valley aquifer; these concentrations typically are found in those parts of the sand and gravel aquifer that are not overlain by clay-rich till. Atrazine was the most commonly detected herbicide in private wells. Concentrations of volatile organic compounds in ground water generally were below Federal drinking-water standards, except near areas of known or suspected contamination. Evaluation of fish and macroinvertebrate community performance in streams and rivers draining the Great and Little Miami River Basins indicates that most streams meet basic aquatic-life-use criteria set by the Ohio Environmental Protection Agency for warmwater habitat. Stream reaches whose biological community performance meet aquatic-lifeuse criteria defined for exceptional warmwater habitat are found in Twin Creek, the Upper Great Miami River, the Little Miami River, and the Whitewater River Basins. Other streams have exhibited significant improvements in biological community performance (and water quality)'that are attributed primarily to reduced pollutant loadings from wastewater-treatment plants upgraded since 1972. Four hydrogeomorphic regions were delineated in the Great and Little Miami River Basins based on distinct and relatively homogeneous natural characteristics. Primary features used to delineate the hydrogeomorphic regions include bedrock geology, surficial geology, physiography, hydrology, soil types, and vegetation. These four regions Till Plains, Drift Plains/Unglaciated, Interlobate, and Fluvial are used in the Great and Little Miami River Basins study to assess the influence of natural features of the environmental setting on surface- and ground-water quality.

Indiana, Ohio↗
USGS2015

Water levels of the Ozark aquifer in northern Arkansas, 2013

The Ozark aquifer is the largest aquifer, both in area of outcrop and thickness, and the most important source of freshwater in the Ozark Plateaus physiographic province, supplying water to northern Arkansas, southeastern Kansas, southern Missouri, and northeastern Oklahoma. The study area includes 16 Arkansas counties lying completely or partially within the Ozark Plateaus of the Interior Highlands major physiographic division. The U.S. Geological Survey, in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey, conducted a study of water levels in the Ozark aquifer within Arkansas. This report presents a potentiometric-surface map of the Ozark aquifer within the Ozark Plateaus of northern Arkansas, representing water-level conditions for the early spring of 2013 and selected water-level hydrographs. The Ozark aquifer in Arkansas is composed of dolomites, limestones, sandstones, and shales of Late Cambrian to Middle Devonian age and ranges in thickness from approximately 1,100 feet (ft) in northwestern Arkansas to more than 4,000 ft in the west-central part of Arkansas. Most wells completed in the aquifer yield between 50 and 100 gallons per minute (gal/min), although some wells may yield as much as 600 gal/min. Water-level measurements were made in wells completed in the Ozark aquifer from February to May 2013. Hydrographs were constructed for nine wells that have water-level measurements with a minimum 20-year period of record. Water-level altitudes in wells used to construct the potentiometric-surface map range from about 1,159 ft to 313 ft above National Geodetic Vertical Datum of 1929 (NGVD 29). The highest water-level altitudes occur in Carroll and Washington Counties while water-level altitudes of less than 400 ft above NGVD 29 are mapped along the eastern and southeastern part of the study area in Independence, Lawrence, Randolph, and Sharp Counties. The lowest water level of 313 ft above NGVD 29 was measured in southwestern Randolph County. The direction of groundwater flow generally is affected by local topography, flowing from high altitudes toward stream valleys. In southern Baxter, eastern Fulton, Independence, eastern Izard, Lawrence, Randolph, and Sharp Counties, the groundwater flow is generally to the south and southeast. In western Fulton and Izard Counties, the groundwater flow is generally to the southwest. In Boone, Marion, Newton, Searcy, and Stone Counties, the groundwater flow is generally to the east and northeast. In eastern Benton, Carroll, Madison, and eastern Washington Counties, the groundwater flow is generally to the north and northeast. In western Benton and western Washington Counties, the groundwater flow is generally to the west and northwest. The general level and shape of the potentiometric surface has changed little since predevelopment. A comparison of the predevelopment potentiometric surface and the 2007, 2010, and 2013 potentiometric surfaces indicate general agreement between the mapped surfaces with the exception of parts of Benton, Boone, Marion, and Washington Counties. In Boone and northern Marion Counties in 2013, water levels have declined when compared to the predevelopment potentiometric surface, although the direction of flow is still to the northeast and north. In southern Marion County, water levels have declined when compared to the predevelopment, 2007, and 2010 potentiometric surfaces, although the direction of flow is towards and along the stream valleys. In western Benton and northwestern Washington Counties, water levels are similar when compared to the predevelopment potentiometric surface, and the direction of flow is to the west and northwest, similar to the predevelopment direction of flow. The mapped 2007 and 2010 potentiometric surfaces are very different from the mapped 2013 potentiometric surface in western Benton and northwestern Washington Counties. The mapped 2013 potentiometric surface in western Benton and northwestern Washington Counties follows the contours of the top of the formation, similar to the predevelopment potentiometric surface. Since 1975, water use in the Ozark aquifer has declined 45 percent, while water levels in Benton, Boone, Marion, and Washington Counties continue to decline. Nine hydrographs were selected as representative of the water-level conditions in their respective counties. Wells in Fulton, Izard, and Newton Counties (station names 20N08W27ABD1, 18N09W15BCB1, and 16N21W34ABC1, respectively) have water levels that are within the usual range of values for their respective counties. Wells in Boone, Marion, and Washington Counties (station names 18N19W19BCC1, 19N15W20ACC1, and 16N32W09ABD1, respectively) have water levels that have recently declined or are declining for the period of record. Wells in Benton, Carroll, and Sharp Counties (station names 19N29W07DAA1, 21N26W17BCC1, and 15N05W06DDD1, respectively) have water levels that have been rising recently.

Arkansas↗
USGS1995

Water quality of storm runoff and comparison of procedures for estimating storm-runoff loads, volume, event-mean concentrations, and the mean load for a storm for selected properties and constituents for Colorado Springs, southeastern Colorado, 1992

The U.S. Environmental Protection Agency requires that municipalities that have a population of 100,000 or greater obtain National Pollutant Discharge Elimination System permits to characterize the quality of their storm runoff. In 1992, the U.S. Geological Survey, in cooperation with the Colorado Springs City Engineering Division, began a study to characterize the water quality of storm runoff and to evaluate procedures for the estimation of storm-runoff loads, volume and event-mean concentrations for selected properties and constituents. Precipitation, streamflow, and water-quality data were collected during 1992 at five sites in Colorado Springs. Thirty-five samples were collected, seven at each of the five sites. At each site, three samples were collected for permitting purposes; two of the samples were collected during rainfall runoff, and one sample was collected during snowmelt runoff. Four additional samples were collected at each site to obtain a large enough sample size to estimate storm-runoff loads, volume, and event-mean concentrations for selected properties and constituents using linear-regression procedures developed using data from the Nationwide Urban Runoff Program (NURP). Storm-water samples were analyzed for as many as 186 properties and constituents. The constituents measured include total-recoverable metals, vola-tile-organic compounds, acid-base/neutral organic compounds, and pesticides. Storm runoff sampled had large concentrations of chemical oxygen demand and 5-day biochemical oxygen demand. Chemical oxygen demand ranged from 100 to 830 milligrams per liter, and 5.-day biochemical oxygen demand ranged from 14 to 260 milligrams per liter. Total-organic carbon concentrations ranged from 18 to 240 milligrams per liter. The total-recoverable metals lead and zinc had the largest concentrations of the total-recoverable metals analyzed. Concentrations of lead ranged from 23 to 350 micrograms per liter, and concentrations of zinc ranged from 110 to 1,400 micrograms per liter. The data for 30 storms representing rainfall runoff from 5 drainage basins were used to develop single-storm local-regression models. The response variables, storm-runoff loads, volume, and event-mean concentrations were modeled using explanatory variables for climatic, physical, and land-use characteristics. The r2 for models that use ordinary least-squares regression ranged from 0.57 to 0.86 for storm-runoff loads and volume and from 0.25 to 0.63 for storm-runoff event-mean concentrations. Except for cadmium, standard errors of estimate ranged from 43 to 115 percent for storm- runoff loads and volume and from 35 to 66 percent for storm-runoff event-mean concentrations. Eleven of the 30 concentrations collected during rainfall runoff for total-recoverable cadmium were censored (less than) concentrations. Ordinary least-squares regression should not be used with censored data; however, censored data can be included with uncensored data using tobit regression. Standard errors of estimate for storm-runoff load and event-mean concentration for total-recoverable cadmium, computed using tobit regression, are 247 and 171 percent. Estimates from single-storm regional-regression models, developed from the Nationwide Urban Runoff Program data base, were compared with observed storm-runoff loads, volume, and event-mean concentrations determined from samples collected in the study area. Single-storm regional-regression models tended to overestimate storm-runoff loads, volume, and event-mean con-centrations. Therefore, single-storm local- and regional-regression models were combined using model-adjustment procedures to take advantage of the strengths of both models while minimizing the deficiencies of each model. Procedures were used to develop single-stormregression equations that were adjusted using local data and estimates from single-storm regional-regression equations. Single-storm regression models developed using model- adjustment proce

Colorado↗
USGS1979

Chemical analyses of coal from the Emery and Ferron Sandstone members of the Mancos Shale, Henry Mountains Field, Wayne and Garfield counties, Utah

As part of a continuing program by the U.S. Geological Survey to collect and chemically analyze representative samples of U.S. coals, 18 samples were collected from the Upper Cretaceous Emery and Ferron Sandstone Members of the Mancos Shale in the Henry Mountains coal field, Wayne and Garfield Counties, Utah (fig. 1). The 18 samples are briefly described in table 1. Thirteen of these samples were collected from seven holes that were drilled in connection with the Henry Mountains EMRIA (Energy Mineral Rehabilitation Inventory and Analyses) study (U.S. Department of the Interior, 1978). The locations of the seven core holes and the four other sampling sites are shown on figure 2. The Henry Mountains coal field is adjacent to the Henry Mountains of southeastern Utah. The basin is a long, narrow syncline about 110 km long and 24 km wide bounded on the west by the Waterpocket Fold and on the east by the Henry Mountains. The most comprehensive geologic report available on the area is by Hunt and others (1953). Their work included a considerable amount of information on the coal resources. Other work in the area concerning coal or stratigraphy of coal bearing units includes: Doelling (1972), Peterson and Ryder (1975), Doelling (1975), Law (1977; 1978; 1979 a,b), and U.S. Department of the Interior (1978). In the Henry Mountains field, there are three coal bearing units in rocks of Late Cretaceous age. In ascending order they are the Dakota Sandstone, the Ferron Sandstone Member of the Mancos Shale, and the Emery Sandstone Member of the Mancos Shale. The coal beds of the Henry Mountains coal field originated as layers of peat that were deposited, for the most part, in coastal swamp environments. Individual coal beds are discontinuous and exhibit large variations in thickness and quality. The thickest and most continuous coal beds occur in the Emery Sandstone Member along or near the axis of the Henry Mountains syncline (Law, 1978).

Utah↗
USGS2000

Geologic studies in Alaska by the U.S. Geological Survey, 1997

The eight papers that follow continue the series of U.S. Geological Survey (USGS) reports on investigations in the geologic sciences in Alaska. The series presents new and sometimes preliminary findings that are of interest to earth scientists in academia, government, and industry; to land and resource managers; and to the general public. Reports presented in Geologic Studies in Alaska cover a broad spectrum of topics from all parts of the State (fig. 1), which serves to emphasize the diversity of USGS efforts to meet the Nation's needs for earth-science information in Alaska. The papers in this volume are organized under the topics Resources, Geologic Framework, and Environment and Climate. Such an organization is intended to reflect the scope and objectives of USGS programs currently active in Alaska. Resource papers include one that presents detailed observations from a Mississippian Zn-Pb-Cu-Ag occurrence in the Brooks Range (Werdon). Mineralogic, chemical, and isotopic data provide the basis for a proposed relationship between this vein-breccia deposit and the shale-hosted massive sulfide deposit type, which includes the active Red Dog mine in the western Brooks Range. Also included under the topic of Resources is a paper that presents geochemical and isotopic data from the Greens Creek and Woewodski Island volcanogenic massive sulfide deposits in southeastern Alaska (Newberry and Brew). The depositional environment and sedimentological setting of Tertiary coal beds in the Matanuska and Susitna Valleys is the focus of a third paper under the topic of Resources (Flores and others). Geologic Framework studies provide background information that is the scientific basis for present and future studies of the environment, mineral and energy resources, paleoclimate, and hazards in Alaska. One paper presents the results of sedimentologic and paleontologic comparisons of lower Paleozoic, deep-water-facies rock units in central Alaska (Dumoulin and others). The authors show which of these units are likely to correlate with one another, suggest likely source regions, and provide a structural restoration of units that have been fragmented by large fault motions. A second framework paper provides a map, rock descriptions, and chemical compositions of volcanic rocks in a newly recognized, geologically young volcanic center in the Aleutian volcanic arc (Hildreth and others). A third paper presents an interesting summary of gravity changes that occurred in south-central Alaska during the great earthquake of 1964 and for the following 25 years (Barnes). Gravity changes correlate with land-elevation changes in some cases, but not in others, which means that different processes are responsible for the gravity changes.

Alaska↗
USGS1968

Geology of the Great Smoky Mountains National Park, Tennessee and North Carolina

The boundary between Tennessee and North Carolina is delimited for about 50 miles in midlength by the crests of the Great Smoky Mountains, which include some of the highest summits in the southeastern United States, and which culminate in Clingmans Dome (alt 6,642 ft). Ramifying spurs and foothills descend northwestward from the State line divide toward the Appalachian Valley in Tennessee, as well as southeastward toward the less regularly disposed mountains of the main part of the Blue Ridge in North Carolina. All the Great Smoky Mountains are heavily forested, the higher summits being covered by spruce and fir, and the lower slopes, by a great variety of hardwoods. Much of this forested mountain wilderness has been set aside for public benefit and enjoyment as Great Smoky Mountains National Park. For most visitors to Great Smoky Mountains National Park, prime attractions are its noble forests, its open coves set gemlike amongst them, the animals of the forests and coves, and the relics of the mountaineers who have made their homes there. Only now and then, when the visitor's trail through the forest must circuit a rough ledge of rock, can he realize that the forest and the soil on which it grows are a mere veneer—a thin cover over the ancient rocks of the mountains. In the Yosemite, the Grand Canyon, and most of our other national parks in the West, the situation is very different; there, the impact of the bedrock of the parks is overwhelming in relation to the plants and animals that live on the bedrock. The terrain of the Great Smoky Mountains, their soils, unconsolidated deposits, and details of slope sculpture tell a geologic story of the last few million years of earth history, a story dominated by the drastic fluctuations of the ice-age climate. Although the mountains themselves were not covered with glacial ice, the climate at this latitude approached glacial conditions, and the mountaintops were occasionally above tree line. Deposits of debris that resulted from the associated accelerated erosion of the hillsides during glacial intervals and the deeply weathered soils produced during the episodes of warm and humid interglacial climate are evident at many places. These climatic oscillations also controlled the flora and fauna. The complex process of adjustment of plants and animals to the prevailing climate is one of the factors that has produced their present great diversity. This latest phase of the geologic history is not further treated in this publication. Maps showing the younger deposits and interpretations based on them are included in the several recent U.S. Geological Survey Professional Papers referred to below. Our concern in this text and its accompanying map (pl. 1) is with the bedrock geology of the Great Smoky Mountains and their surroundings, and with the story of far earlier times in earth history—when there were no Great Smoky Mountains, and when the geography and the landscape were very different from those today. Because of the forest cover and the scantiness of rock outcrops, the bedrock geology of the Great Smoky Mountains is not easy to decipher, and this difficulty is compounded by the enigmatic nature of most of the rocks themselves. It thus has come about that knowledge of the geology of the mountains has lagged behind that in surrounding regions. Following pioneer investigations of Safford (1869) and of Keith (1895, 1896), little further geologic study of the mountains was made until after World War II. The present text and map summarize the results of the more recent investigations, details of which are given at much greater length in a set of U.S. Geological Survey Professional Papers (Hamilton, 1961; Hadley and Goldsmith, 1963; King, 1964; Neuman and Nelson, 1965).

North Carolina, Tennessee↗