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At least 541 records · Page 30Linked to original sources
USGS1997

Hydrogeology and potential for ground-water development, carbonate-rock aquifers, southern Nevada and southeastern California

Seventeen hydrographic areas in southern Nevada were assessed for the ground-water development potential of the underlying carbonate-rock aquifers on the basis of geologic and hydrologic information developed as part of the Nevada Carbonate Aquifers Study and information compiled from previous investigations. All selected areas lie within a miogeoclinal belt where thick accumulations of carbonate rock followed by major episodes of compression and extension have greatly modified the region. Most of the selected hydrographic areas lie within the less extended terranes; however, several areas, or parts of areas, lie within severely extended terranes where carbonate rocks have been greatly thinned, or where deformed blocks of carbonate rock are discontinuous and isolated from surrounding carbonate rock aquifers. Three principal criteria were used to assess the development potential of each selected hydrographic area. These quantitative criteria are: (1) depth to water, (2) depth to and thickness of carbonate rocks, and (3) water quality. Other site-specific factors, such as accessibility and potential effects of ground-water development, are also discussed. Results suggest that sites with high potential for development may be scarce in southern Nevada. Many areas described as favorable on the basis of the three quantitative criteria were deemed unfavorable on the basis of possible short- and long-term effects associated with development and on the amount of available data used to make the assessment. The most favorable sites may be in more severely extended terranes, where development of isolated blocks (of carbonate-rock aquifer material) would be less likely to affect neighboring areas.

California, Nevada↗
USGS1998

Vulnerability of coastal wetlands in the Southeastern United States: climate change research results, 1992-97

As part of the USGCRP research framework on coastal lands and ecosystems, the Biological Resources Division of the U.S. Geological Survey (National Wetlands Research Center) entered into partnership with Rice University, Louisiana State University, Duke University, Clemson University, University of Southwestern Louisiana, University of Georgia, and the Virginia Institute of Marine Studies (University of Virginia ) to (1) document the current state vulnerability of coastal ecosystems including an assessment of past changes in land cover, (2) develop an understanding of the processes which underlie these changes, and (3) predict the extent of future alterations to these habitats and the consequences for the sustainability of the resource and land base. This document summarized the initial findings of our collaborative efforts. Overall, the studies exemplify an integrated approach addressing questions at the species, community, and landscape levels of organization and focusing on factors related to hydroperiod, sea-level rise, disturbance events, and coastal marsh submergence.

Biological Science Report↗
USGS2009

Geologic Setting and Hydrogeologic Units of the Columbia Plateau Regional Aquifer System, Washington, Oregon, and Idaho

The Columbia Plateau Regional Aquifer System (CPRAS) covers approximately 44,000 square miles of northeastern Oregon, southeastern Washington, and western Idaho. The area supports a $6 billion per year agricultural industry, leading the Nation in production of apples and nine other commodities (State of Washington Office of Financial Management, 2007; U.S. Department of Agriculture, 2007). Groundwater availability in the aquifers of the area is a critical water-resource management issue because the water demand for agriculture, economic development, and ecological needs is high. The primary aquifers of the CPRAS are basalts of the Columbia River Basalt Group (CRBG) and overlying basin-fill sediments. Water-resources issues that have implications for future groundwater availability in the region include (1) widespread water-level declines associated with development of groundwater resources for irrigation and other uses, (2) reduction in base flow to rivers and associated effects on temperature and water quality, and (3) current and anticipated effects of global climate change on recharge, base flow, and ultimately, groundwater availability. As part of a National Groundwater Resources Program, the U.S. Geological Survey began a study of the CPRAS in 2007 with the broad goals of (1) characterizing the hydrologic status of the system, (2) identifying trends in groundwater storage and use, and (3) quantifying groundwater availability. The study approach includes documenting changes in the status of the system, quantifying the hydrologic budget for the system, updating the regional hydrogeologic framework, and developing a groundwater-flow simulation model for the system. The simulation model will be used to evaluate and test the conceptual model of the system and later to evaluate groundwater availability under alternative development and climate scenarios. The objectives of this study were to update the hydrogeologic framework for the CPRAS using the available geologic mapping and well information and to develop a digital, three-dimensional hydrogeologic model that could be used as the basis of a groundwater-flow model. This report describes the principal geologic and hydrogeologic units of the CPRAS and geologic map and well data that were compiled as part of the study. The report also describes simplified regional hydrogeologic sections and unit extent maps that were used to conceptualize the framework prior to development of the digital 3-dimensional framework model.

Idaho, Oregon, Washington↗
USGS1954

The gold pan: A neglected geological tool

The gold pan is ordinarily regarded as a tool for sampling placer deposits. Another and very important application is shown to be the sampling and study of decomposed bedrock, in regions where outcrops of hardrock are scarce or lacking. This technique was proposed and used by Derby, an American geologist who worked for many years in Brazil. The importance of this method has not been generally recognized, and the writer recalls it to the attention of geologists. An important application is shown to exist in the study of the decomposed bedrock, known as saprolite, that is so widespread in the Piedmont province of the southeastern United States. Using this technique, two projects have already been successfully completed in this region, and the success attained in both sets a new standard for geological exploration and mapping in areas where saprolite constitutes the dominant type of exposure. The technique of panning for heavy and semiheavy accessory minerals is described. Types of pans, factors in panning, the operation of panning, and the processing of concentrates in the field are briefly discussed. The gold pan, in the hands of an experienced operator, is shown to be a versatile and efficient field tool, which is completely independent of laboratory facilities. © 1954 Society of Economic Geologists, Inc.

Economic Geology↗
USGS1999

Synopsis of strontium isotope variations in groundwater at Aspo, southern Sweden

Strontium isotope ratios are used to identify end-member ground-water compositions at Aspo in southeastern Sweden where the Hard Rock Laboratory (HRL) has been constructed to evaluate the suitability of crystalline rock for the geologic disposal of nuclear waste. The Hard Rock Laboratory is a decline (tunnel) constructed in 1.8 Ga-old granitic rock that forms islands in an archipelago along the Swedish coast. Ground-water samples were obtained for isotopic analyses from boreholes drilled from the surface and from side boreholes drilled within the HRL. Infiltration at Aspo occurs primarily through fractures zones in the granitic bedrock beneath thin soils throughout the area. Because of extremely low Sr concentrations, rain and snow are not important contributors to the Sr isotope budget of the ground-water system. At shallow levels, water percolating downward along fractures and fracture zones acquires a ??87Sr between +9.5 and +10.0??? and maintains this value downward while Sr concentrations increase by two orders of magnitude. Ground-water samples from both boreholes and from in the HRL show the effects of mixing with saline waters containing as much as 59 mg/L Sr and ??87Sr values as large as +13.92%, Baltic Sea water is a potential component of the groundwater system with ??87Sr values only slightly larger than modern marine values (+0.3???) but with much lower concentrations (1.5 mg/L) than ocean water (8 mg/L). However, because of large Sr concentration differences between the saline groundwater (59 mg/L) and Baltic Sea water (1.5 rag/L), ??87Sr values are not particularly sensitive indicators of sea-water intrusion even though their ??87Sr values differ substantially.

Applied Geochemistry↗
USGS2001

Ground-water recharge and flowpaths near the edge of the Decorah-Platteville-Glenwood confining unit, Rochester, Minnesota

The primary source of ground water for the city of Rochester, Olmsted County, southeastern Minnesota is the St. Peter-Prairie du Chien-Jordan aquifer. Based on results of a previous U.S. Geological Survey investigation in the Rochester area, relatively high rates of areal recharge to the St. Peter-Prairie du Chien-Jordan aquifer occur along the edge of the overlying Decorah-Platteville-Glenwood confining unit. The primary source of water to the zone of increased recharge along the edge of the confining unit is the upper carbonate aquifer. Ground-water recharge rates to the St. Peter-Prairie du Chien-Jordan aquifer during all of 1998 ranged from 1.9 to 25.5 in./yr (inches per year). Recharge rates were greatest near the edge of the Decorah-Platteville-Glenwood confining unit and least where the confining unit is thick and is overlain by the upper carbonate aquifer (mean of 2.0 in./yr). Recharge rates downslope from the edge of the confining unit were greatest to the St. Peter on the slope entering the main South Fork Zumbro River Valley. Results of groundwater age dating using chlorofluorocarbons (CFCs) indicated recharge dates ranging from (1) the mid-1950’s to the early 1990’s for the St. Peter, (2) the late 1960’s to approximately 1990 for the Prairie du Chien, and (3) the early to mid-1950’s for the Jordan. Cross-sectional model simulations indicated that most of the areal recharge entering the aquifer system through the upper carbonate aquifer discharges from springs and seeps. Of the 2.28 ft3/s (cubic feet per second) of areal recharge that enters the upper carbonate aquifer, 2.23 ft3/s is discharged from the aquifer by springs and seeps. Results indicate that areal recharge to the upper Prairie du Chien moves primarily westward and discharges to Bear Creek. Areal recharge rates derived from hydrograph analysis, CFC age-dating, and cross-sectional model analysis were much greater to the St. Peter downslope from the edge of the Decorah-Platteville-Glenwood confining unit (25.5, 35.3, and 23.75 in./yr, respectively) than occurs to the Prairie du Chien in any hydrogeologic setting. The model-simulated discharge from springs and seeps in the lower part of the upper carbonate aquifer represents a potential source of water of 33 in./yr to the St. Peter unit, similar to the estimated areal recharge rates derived from hydrograph analysis and CFC age-dating. The water withdrawn by pumped wells or discharged to Bear Creek is derived predominantly from areal recharge near the edge of the Decorah-Platteville-Glenwood confining unit (0.47 ft 3 /s), rather than from water that has leaked downward through the Decorah unit (0.03 ft 3 /s). Model simulated discharge through springs and seeps in the lower part of the upper carbonate aquifer (0.21 ft 3 /s) represents a potential source of water to the St. Peter-Prairie du Chien-Jordan aquifer.

Minnesota↗
USGS1998

Cotton herbicides in the surface waters of the Mississippi Alluvial Plain (the Delta)

The U.S. Geological Survey is conducting two studies to assess the environmental fate of herbicides used in cotton producing areas of the southeastern United States. The first study is evaluating surface-water quality on a regional basis and relating water quality to land use. The second study is examining the use of Best Management Practices to reduce off-site movement of agricultural chemicals in surface-water runoff. Maximum concentrations of the herbicides fluometuron and norflurazon in samples from surface water in edge-of-field studies were 23 and 7 micrograms per liter, respectively. Also, they were detected in the runoff of nearly every sampled storm for the 1997 water year at concentrations higher than 1.0 microgram per liter. Fluometuron and norflurazon were measured frequently in samples from rivers and streams in cotton producing areas, but the frequency of occurrence and the maximum concentrations were less than those in the edge-of-field studies.

Conference Paper↗
USGS1972

Geologic map of the Fracastorius Quadrangle of the Moon

The multi-ringed Nectaris basin ( Hartmann and Kuiper, 1962) dominates the Fracastorius quadrangle. The basin is 840 km across as measured from the outermost ring and lies athwart four quadrangles. Frac astorius , the southeastern quadrangle , straddles the three rings of the basin (fig. 1 ). In this quadrangle most pre- Imbri an structures and many depositions were formed by the Nectaris impact. Furthermore, the emplacement of many younger deposi ts was controlled by basin structures and locally by probable multi-ring structures related to the Fecunditatis basin center ed northeast of the quadrangle. Other geologic features in the area include diverse mantling deposits and both primary impact craters and secondary impact craters produced by ejecta from distant impacts .

IMAP↗
USGS2015

A comparison of methods to predict historical daily streamflow time series in the southeastern United States

Effective and responsible management of water resources relies on a thorough understanding of the quantity and quality of available water. Streamgages cannot be installed at every location where streamflow information is needed. As part of its National Water Census, the U.S. Geological Survey is planning to provide streamflow predictions for ungaged locations. In order to predict streamflow at a useful spatial and temporal resolution throughout the Nation, efficient methods need to be selected. This report examines several methods used for streamflow prediction in ungaged basins to determine the best methods for regional and national implementation. A pilot area in the southeastern United States was selected to apply 19 different streamflow prediction methods and evaluate each method by a wide set of performance metrics. Through these comparisons, two methods emerged as the most generally accurate streamflow prediction methods: the nearest-neighbor implementations of nonlinear spatial interpolation using flow duration curves (NN-QPPQ) and standardizing logarithms of streamflow by monthly means and standard deviations (NN-SMS12L). It was nearly impossible to distinguish between these two methods in terms of performance. Furthermore, neither of these methods requires significantly more parameterization in order to be applied: NN-SMS12L requires 24 regional regressions—12 for monthly means and 12 for monthly standard deviations. NN-QPPQ, in the application described in this study, required 27 regressions of particular quantiles along the flow duration curve. Despite this finding, the results suggest that an optimal streamflow prediction method depends on the intended application. Some methods are stronger overall, while some methods may be better at predicting particular statistics. The methods of analysis presented here reflect a possible framework for continued analysis and comprehensive multiple comparisons of methods of prediction in ungaged basins (PUB). Additional metrics of comparison can easily be incorporated into this type of analysis. By considering such a multifaceted approach, the top-performing models can easily be identified and considered for further research. The top-performing models can then provide a basis for future applications and explorations by scientists, engineers, managers, and practitioners to suit their own needs.

Scientific Investigations Report↗
USGS2017

Simulations of hydrologic response in the Apalachicola-Chattahoochee-Flint River Basin, Southeastern United States

A suite of hydrologic models has been developed for the Apalachicola-Chattahoochee-Flint River Basin (ACFB) as part of the National Water Census, a U.S. Geological Survey research program that focuses on developing new water accounting tools and assessing water availability and use at the regional and national scales. Seven hydrologic models were developed using the Precipitation-Runoff Modeling System (PRMS), a deterministic, distributed-parameter, process-based system that simulates the effects of precipitation, temperature, land cover, and water use on basin hydrology. A coarse-resolution PRMS model was developed for the entire ACFB, and six fine-resolution PRMS models were developed for six subbasins of the ACFB. The coarse-resolution model was loosely coupled with a groundwater model to better assess the effects of water use on streamflow in the lower ACFB, a complex geologic setting with karst features. The PRMS coarse-resolution model was used to provide inputs of recharge to the groundwater model, which in turn provide simulations of groundwater flow that were aggregated with PRMS-based simulations of surface runoff and shallow-subsurface flow. Simulations without the effects of water use were developed for each model for at least the calendar years 1982–2012 with longer periods for the Potato Creek subbasin (1942–2012) and the Spring Creek subbasin (1952–2012). Water-use-affected flows were simulated for 2008–12. Water budget simulations showed heterogeneous distributions of precipitation, actual evapotranspiration, recharge, runoff, and storage change across the ACFB. Streamflow volume differences between no-water-use and water-use simulations were largest along the main stem of the Apalachicola and Chattahoochee River Basins, with streamflow percentage differences largest in the upper Chattahoochee and Flint River Basins and Spring Creek in the lower Flint River Basin. Water-use information at a shorter time step and a fully coupled simulation in the lower ACFB may further improve water availability estimates and hydrologic simulations in the basin.

Apalachicola-Chattahoochee-Flint River Basin↗
USGS2008

Grazed riparian management and stream channel response in southeastern Minnesota (USA) streams

The U.S. Department of Agriculture-Natural Resources Conservation Service has recommended domestic cattle grazing exclusion from riparian corridors for decades. This recommendation was based on a belief that domestic cattle grazing would typically destroy stream bank vegetation and in-channel habitat. Continuous grazing (CG) has caused adverse environmental damage, but along cohesive-sediment stream banks of disturbed catchments in southeastern Minnesota, short-duration grazing (SDG), a rotational grazing system, may offer a better riparian management practice than CG. Over 30 physical and biological metrics were gathered at 26 sites to evaluate differences between SDG, CG, and nongrazed sites (NG). Ordinations produced with nonmetric multidimensional scaling (NMS) indicated a gradient with a benthic macroinvertebrate index of biotic integrity (IBI) and riparian site management; low IBI scores associated with CG sites and higher IBI scores associated with NG sites. Nongrazed sites were associated with reduced soil compaction and higher bank stability, as measured by the Pfankuch stability index; whereas CG sites were associated with increased soil compaction and lower bank stability, SDG sites were intermediate. Bedrock geology influenced NMS results: sites with carbonate derived cobble were associated with more stable channels and higher IBI scores. Though current riparian grazing practices in southeastern Minnesota present pollution problems, short duration grazing could reduce sediment pollution if managed in an environmentally sustainable fashion that considers stream channel response. ?? 2008 Springer Science+Business Media, LLC.

Environmental Management↗
USGS1962

Geology of the Powder River Basin, Wyoming and Montana, with reference to subsurface disposal of radioactive wastes

The Powder River Basin is a structural and topographic basin occupying an area of about 20,000 square miles in northeastern Wyoming arid southeastern Montana. The Basin is about 230 miles long in a northwest-southeast direction and is about 100 miles wide. It is bounded on three sides by mountains in which rocks of Precambrian age are exposed. The Basin is asymmetrical with a steep west limb adjacent to the Bighorn Mountains and a gentle east limb adjacent to the Black Hills. Sedimentary rocks within the Basin have a maximum thickness of about 18,000 feet and rocks of every geologic period are represented. Paleozoic rocks are about 2,500 feet thick and consist of marine bonate rocks and sandstone; Mesozoic rocks are about 9,500 feet thick and consist of both marine and nonmarine siltstone and sandstone; and Cenozoic rocks are from 4,000 to 6,000 feet thick and consist of coal-bearing sandstone and shale. Radioactive waste could be stored in the pore space of permeable sandstone or in shale where space could be developed. Many such rock units that could be used for storing radioactive wastes are present within the Powder River Basin. Permeable sandstone beds that may be possible reservoirs for storage of radioactive waste are present throughout the Powder River Basin. These include sandstone beds in the Flathead Sandstone and equivalent strata in the Deadwood Formation, the Tensleep Sandstone and equivalent strata in the Minnelusa Formation and the Sundance Formation in rocks of pre-Cretaceous age. However, most of the possible sandstone reservoirs are in rocks of Cretaceous age and include sandstone beds in the Fall River, Lakota, Newcastle, Frontier, Cody, and Mesaverde Formations. Problems of containment of waste such as clogging of pore space and chemical incompatibility would have to be solved before a particular sandstone unit could be selected for waste disposal. Several thick sequences of impermeable shale such as those in the Skull Creek, Mowry, Frontier, Belle Fourche, Cody, Lewis, and Pierre Formations, occur in rocks of Cretaceous age in the Basin. Limited storage space for liquid waste might be developed in impermeable shale by fracturing the shale and space for calcined or fused waste could be developed by mining cavities.

Open-File Report↗
USGS1999

Yucca Mountain as a Radioactive-Waste Repository

Yucca Mountain straddles the west boundary of the Nevada Test Site in an arid, remote, and thinly populated region of southwestern Nevada. It is the potential site of a monitored geologic repository for the Nation’s commercial and military spent nuclear fuel, high-level radioactive waste derived from reprocessing of uranium and plutonium, surplus plutonium, and other nuclear-weapons materials. (Collectively, these radioactive materials are known as high-level waste [HLW] and are to be distinguished from the low-level radioactive waste to be stored at the recently opened Waste Isolation Pilot Plant in southeastern New Mexico.) Tens of thousands of metric tons of HLW is presently stored at more than a hundred sites in 40 States (fig. 1). The fundamental rationale for a geologic repository for radioactive materials is to securely isolate them from the environment and its occupants to the greatest extent possible.

Nevada↗
USGS2014

The nickel deposits of Yakobi Island, southeastern Alaska

Some of the large, low‐grade nickel‐copper deposits of Bohemia Basin, Yakobi Island, south‐eastern Alaska, which previously had been mapped and studied by the United States Geological Survey, were explored during parts of 1941 and 1942 by the United States Bureau of Mines. The Gealogical Survey interpreted the geologic features of the deposits as revealed by the work of the Bureau of Mines. The explorations were made largely by diamond‐drilling. The three deposits most extensively tested are arranged around a small valley.

Alaska↗
USGS1995

Similar agricultural areas, different ground-water quality, Red River of the North Basin, 1993-95

The U.S. Geological Survey has studied the ground-water quality within two areas of the Red River of the North Basin in southeastern North Dakota and west-central Minnesota. Although both areas are underlain by sandy surficial aquifers over which intensive irrigated agriculture dominates the land use, their ground-water quality differs. Ground water from the eastern study area has significantly higher concentrations of nitrate and agricultural herbicides than does ground water from the western area. Major differences in rainfall and minor differences in soils, depth to ground water, and agricultural practices between these two areas can account for the differences measured in ground-water quality. These same factors may indicate changes in ground-water quality from agricultural land uses in other surficial aquifers in the Red River of the North Basin.

Minnesota, North Dakota, South Dakota↗
USGS1925

Rock formations in the Colorado Plateau of Southeastern Utah and Northern Arizona

The field work of which this report is a record was done in the summer and fall of 1921 by members of the United States Geological Survey. A project to build a large storage dam at Lees Ferry, on Colorado River in northern Arizona, called for a detailed topographic survey of the area covered by the project, for the purpose of determining the capacity of the reservoir. This work was undertaken by the United States Geological Survey in cooperation with the Southern California Edison Co. Three surveying parties were sent to the field, each accompanied by a geologist, whose specific duty was to study and report on the rock formations within the area to be flooded. One topographic party, under A. T. Fowler, which started at Lees Ferry and worked up stream in Arizona, was accompanied by Kirk Bryan. Another party, under K. W. Trimble, which started near Bluff and worked down the San Juan and thence down the Colorado, was accompanied by H. D. Miser. The third party, under W. R. Chenoweth, worked from Fremont River to the Waterpocket Fold and then returned to Green River, Utah, and traversed Cataract Canyon during the period of low water. C. R. Longwell was with this party until September, when his place was taken by Sidney Paige. Mr. Paige, in company with the Kolb brothers, E. C. La Rue, and Henry Ranch, left the Chenoweth party after Cataract Canyon had been surveyed and rowed down the Colorado to the mouth of the San Juan, where they were joined by Mr. Miser. Then they took a hurried trip by boat down the Colorado to Lees Ferry, making a few short stops and visiting the famous Rainbow Bridge. Thus the geology of the canyons of Colorado and San Juan rivers and of the lower parts of tributary canyons was examined continuously, and reconnaissance work was done in the country back from the rivers. At the same time a fourth party, under R. C. Moore, was mapping parts of Kane, Garfield, and Wayne counties, Utah, to determine whether oil might be found there. The present paper includes brief descriptions of the rocks of the regions traversed, detailed geologic sections, and columnar sections measured not only by the geologists who accompanied these parties but by other geologists who have worked in the same regions or in adjoining regions. The positions of the columnar sections measured and many of the other sections are shown on Figure 1.

Arizona;Utah↗
USGS2013

Estimates of the volume of water in five coal aquifers, Northern Cheyenne Indian Reservation, southeastern Montana

The Tongue River Member of the Tertiary Fort Union Formation is the primary source of groundwater in the Northern Cheyenne Indian Reservation in southeastern Montana. Coal beds within this formation generally contain the most laterally extensive aquifers in much of the reservation. The U.S. Geological Survey, in cooperation with the Northern Cheyenne Tribe, conducted a study to estimate the volume of water in five coal aquifers. This report presents estimates of the volume of water in five coal aquifers in the eastern and southern parts of the Northern Cheyenne Indian Reservation: the Canyon, Wall, Pawnee, Knobloch, and Flowers-Goodale coal beds in the Tongue River Member of the Tertiary Fort Union Formation. Only conservative estimates of the volume of water in these coal aquifers are presented. The volume of water in the Canyon coal was estimated to range from about 10,400 acre-feet (75 percent saturated) to 3,450 acre-feet (25 percent saturated). The volume of water in the Wall coal was estimated to range from about 14,200 acre-feet (100 percent saturated) to 3,560 acre-feet (25 percent saturated). The volume of water in the Pawnee coal was estimated to range from about 9,440 acre-feet (100 percent saturated) to 2,360 acre-feet (25 percent saturated). The volume of water in the Knobloch coal was estimated to range from about 38,700 acre-feet (100 percent saturated) to 9,680 acre-feet (25 percent saturated). The volume of water in the Flowers-Goodale coal was estimated to be about 35,800 acre-feet (100 percent saturated). Sufficient data are needed to accurately characterize coal-bed horizontal and vertical variability, which is highly complex both locally and regionally. Where data points are widely spaced, the reliability of estimates of the volume of coal beds is decreased. Additionally, reliable estimates of the volume of water in coal aquifers depend heavily on data about water levels and data about coal-aquifer characteristics. Because the data needed to define the volume of water were sparse, only conservative estimates of the volume of water in the five coal aquifers are presented in this report. These estimates need to be used with caution and mindfulness of the uncertainty associated with them.

Montana↗