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USGS1956

Semiquantitative spectrographic analysis and rank correlation in geochemistry

The rank correlation coefficient, r s , which involves less computation than the product moment correlation coefficient, r, can be used to indicate the degree of relationship between two elements. The methods is applicable in situations where the assumptions underlying distribution correlation theory may not be satisfied. Semiquantitative spectrographic analyses can be used to calculate rank correlations between elements because the results are already partly ranked in an analytical report.

Trace Elements Investigations↗
USGS1962

Physical properties of evaporite minerals

The data in the following tables were abstracted from measurements of physical properties of evaporite minerals or of equivalent synthetic compounds. The compounds considered are the halide and sulfate salts which supposedly precipitated from evaporating ocean water and which form very extensive and thick "rock salt" beds. These beds are composed almost entirely of NaCl. In places where the beds are deeply buried and where fractures occur in the overlying rocks, the salt is plastically extruded upward as in a pipe to form the "salt domes". Most of the tables are for NaCl, both the natural (halite) and the synthetic salt, polycrystalline and single crystals. These measurements have been collected for use 1) in studies on storage of radioactive wastes in salt domes or beds, 2) in calculations concerned with nuclear tests in salt domes and beds, and 3) in studies of phenomena in salt of geologic interest. Rather than an exhaustive compilation of physical property measurements, there tables represent a summary of data from accessible sources. As limitations of time have presented making a more systematic and comprehensive selection, the data given may seem arbitrarily chosen. Some of the data listed are old, and newer, more accurate data are undoubtedly available. Halite (an synthetic NaCl) has been very thoroughly studied because of its relatively simple and highly symmetrical crystal structure, its easy availability naturally or synthetically, both in single crystals and polycrystalline, its useful and scientifically interesting properties, and its role as a compound of almost purely ionic bonding. The measurements of NaCl in the tables, however, represent only a small part of the total number of observations; discrimination was necessary to keep the size of the tabulations manageable. The physical properties of the evaporite minerals other than halite and sylvite have received only desultory attention of experiementalists, and appear in only a few tables. The effects of temperature, hydrostatic pressure, stress difference, and other mechanical, eletrical, and optical conditions on the physical properties have probably been observed more completely on NaCl than on any other solid substance, which makes it a unique and important substance. Several new and important phenomena have been observed first on it. The mechanical properties of NaCl, for example, depend very strongly on the condition and the composition of the gas or liquid in contact with the sample surface; the data are sparse as yet and are not reported here.

Trace Elements Investigations↗
USGS2003

Reconnaissance of acid drainage sources and preliminary evaluation of remedial alternatives at the Copper Bluff mine, Hoopa Valley Reservation, California

Acidic drainage from the inactive Copper Bluff mine cascades down a steep embankment into the Trinity River, on the Hoopa Valley Reservation in northern California. The Copper Bluff mine produced about 100,000 tons of sulfide-bearing copper-zinc-gold-silver ore during 1957–1962. This report summarizes the results of a water-resources investigation begun by the U.S. Geological Survey in 1994 with the overall objective of gathering sufficient geochemical, hydrologic, and geologic information so that a sound remediation strategy for the Copper Bluff mine could be selected and implemented by the Hoopa Valley Tribe. This study had the following specific objectives: (1) monitor the quality and quantity of the mine discharge, (2) determine seasonal variability of metal concentrations and loads, (3) map and sample the underground mine workings to determine sources of flow and suitability of mine plugging options, and (4) analyze the likely consequences of various remediation and treatment options. Analysis of weekly water samples of adit discharge over parts of two wet seasons (January to July 1995 and October 1995 to May 1996) shows that dissolved copper (Cu) and zinc (Zn) concentrations (in samples filtered with 0.20-micrometer membranes) varied systematically in a seasonal pattern. Metal concentrations increased dramatically in response to the first increase in discharge, or first flush, early in the wet season. The value of Zn/Cu in the adit discharge exhibited systematic seasonal variations; an annual Zn/Cu cycle was observed, beginning with values between 3 and 5 during the main part of the wet season, rising to values between 6 and 10 during the period of lowest discharge late in the dry season, and then dropping dramatically to values less than 3 during the first-flush period. Values of pH were fairly constant in the range of 3.1 to 3.8 throughout the wet season and into the beginning of the dry season, but rose to values between 4.5 and 5.6 during the period of lowest discharge, from October to early December 1995. Underground reconnaissance was conducted once during dry-season conditions (September 1995) and twice during wet-season conditions (March 1995 and March 1996). The main tunnel was accessed to a distance of about 600 feet from the portal entrance. Water samples were collected at nine locations along the floor of the main tunnel and from several ore shoots to evaluate the contributions of water and dissolved constituents from different portions of the mine. Values of pH ranged from 2.5 to 6.4 at different underground locations, concentrations of copper ranged from 0.020 to 44 mg/L (milligram per liter), zinc from 6.3 to 160 mg/L, and cadmium from 0.010 to 0.47 mg/L. Discharge from the ore shoots ranged from less than 1 gallon per minute to more than 30 gallons per minute and was always a small component of the total mine flow compared with the tunnel floor drainage. During March 1996, the main flow originated in the northernmost portion of the underground workings (inaccessible) and mixed with an unknown quantity of water upwelling from flooded lower workings. High-water marks observed on the tunnel walls indicate that past blockages impounded more than 100,000 gallons of water. Sudden release of a large volume of metal-rich water could have serious effects on fish and other aquatic resources in the Trinity River. Because of the hydrogeologic setting, mine plugging is not likely to offer an effective long-term solution to the problem of acid mine drainage at the Copper Bluff mine. The underground workings are close to a state highway and underlie a 500-foot-high bluff with highly fractured rocks that seep during the wet season. Total plugging likely would result in additional uncontrolled seepage and could potentially destabilize the highway. Partial plugging to restrict flow during periods of highest discharge may provide benefits in terms of reduced risk of catastrophic release without the additional risks associated with total plugging. Passive water treatment methods such as wetlands or anoxic limestone drains are unlikely to succeed at the Copper Bluff mine because of the lack of available space. A covered conveyance for the discharge directly from the mine portal to the Trinity River is a low-cost remedial alternative that would not reduce metal loadings to the Trinity River, but would reduce pathways of metal exposure to humans and wildlife. Lime neutralization or innovative, active water treatment methods such as bioreactors represent high-cost remedial alternatives that likely would be successful if sufficient resources were available for adequate design, testing, construction, long-term maintenance, and sludge disposal.

California↗
USGS2003

Hydrogeology and Ground-Water Quality of Brunswick County, North Carolina

Brunswick County is the southernmost coastal county in North Carolina and lies in the southeastern part of the Coastal Plain physiographic province. In this report, geologic, hydrologic, and chemical data were used to investigate and delineate the hydrogeologic framework and ground-water quality of Brunswick County. The major aquifers and their associated confining units delineated in the Brunswick County study area include, from youngest to oldest, the surficial, Castle Hayne, Peedee, Black Creek, upper Cape Fear, and lower Cape Fear aquifers. All of these aquifers, with the exception of the Castle Hayne aquifer, are located throughout Brunswick County. The Castle Hayne aquifer extends across only the southeastern part of the county. Based on available data, the Castle Hayne and Peedee confining units are missing in some areas of Brunswick County, which allows direct hydraulic contact between the surficial aquifer and underlying Castle Hayne or Peedee aquifers. The confining units for the Black Creek, upper Cape Fear, and lower Cape Fear aquifers appear to be continuous throughout Brunswick County. In examining the conceptual hydrologic system for Brunswick County, a generalized water budget was developed to better understand the natural processes, including precipitation, evapotranspiration, and stream runoff, that influence ground-water recharge to the shallow aquifer system in the county. In the generalized water budget, an estimated 11 inches per year of the average annual precipitation of 55 inches per year in Brunswick County is estimated to infiltrate and recharge the shallow aquifer system. Of the 11 inches per year that recharges the shallow system, about 1 inch per year is estimated to recharge the deeper aquifer system. The surficial aquifer in Brunswick County is an important source of water for domestic supply and irrigation. The Castle Hayne aquifer is the most productive aquifer and serves as the principal ground-water source of municipal supply for the county. The upper part of the Peedee aquifer is an important source of ground-water supply for domestic and commercial use. Ground water in the lower part of the Peedee aquifer and the underlying aquifers is brackish and is not known to be used as a source of supply in Brunswick County. Most of the precipitation that recharges the surficial aquifer is discharged to local streams that drain into the Waccamaw River, Cape Fear River, and Atlantic Ocean. Recharge to the Castle Hayne aquifer occurs primarily from the surficial aquifer. Recharge to the Peedee aquifer occurs primarily from the surficial and Castle Hayne aquifers, with some upward leakage of water also occurring from the underlying Black Creek aquifer. Discharge from the Castle Hayne and Peedee aquifers occurs to local streams, the Cape Fear River, and the Atlantic Ocean. Evaluation of water-level data for the period January 1970 through May 2002 indicated no apparent long-term temporal trends in water levels in the surficial and Castle Hayne aquifers and in the upper part of the Peedee aquifer. The most significant water-level trends were noted for wells tapping the lower part of the Peedee aquifer and tapping the Black Creek aquifer where water levels have declined as much as 41 and 37 feet, respectively. These ground-water-level declines are attributed to regional ground-water pumping in areas outside of Brunswick County. Water-level data for Brunswick County wells tapping the upper Cape Fear and lower Cape Fear aquifers tend to fluctuate within a fairly uniform range with no apparent temporal trend noted. Analysis of vertical hydraulic gradients during this same period primarily indicate downward flow of ground water within and among the surficial, Castle Hayne, and Peedee aquifers. The vertical flow of ground water in the Black Creek aquifer is upward into the overlying Peedee aquifer. Upward flow also is noted for the upper and lower Cape Fear aquifers. Historic and recent analytic data were evaluated to better understand the sources of water contained in Brunswick County aquifers and the suitability of the water for consumption. Based on analytical results obtained for recent samples collected during this study, ground water from the surficial aquifer, Castle Hayne aquifer, and upper part of the Peedee aquifer appears to be generally suitable for drinking water. Although concentrations of iron and manganese commonly exceeded the drinking-water standards, the concern generally associated with the occurrence of these analytes in a water supply is one of aesthetics. In all samples, nitrate, nitrite, and sulfate were detected at concentrations less than drinkingwater standards. Based on historic analytical data, the brackish water in the lower part of the Peedee aquifer and in the Black Creek, upper Cape Fear, and lower Cape Fear aquifers is classified as a sodium-chloride type water. The presence of brackish water in these deeper systems combined with upward vertical gradients presents the potential for upward migration of brackish water into overlying aquifers, or upconing beneath areas of pumping. The current (2001) location of the boundary between freshwater and brackish water in Brunswick County aquifers is unknown.

North Carolina↗
USGS1985

Estimation of flood peaks from channel characteristics in Ohio

Regression equations were developed to estimate flood peaks with selected recurrence intervals of 2 to 100 years for Ohio streams with alluvial and bedrock channels. CHannel-geometry characteristics, rather than basin characteristics, were used as independent variables. Width of active channel was the only channel-geometry characteristic significant at the 5-percent level in the estimating equations for alluvial channels. Standard errors of estimate for those equations range for the 100-year flood peak. The equations were developed from data collected at 142 gaging stations that have active-channel widths ranging from 2 to 495 feet. For streams with bedrock or firm channels, depth of the bankfull channel and active-channel width were statistically significant characteristics at the 5-percent level for all but the 2-year recurrence interval flood-peak equation, for which only active-channel width was statistically significant. Standard errors of estimate range from 33 percent for the 5-year flood peak to 40 percent for the 100-year flood peak when both significant variables are included in the equations. Standard errors of estimate range from 36 percent to 46 percent when only the active-channel width independent variable is used. These equations are based on channel-geometry data collected at 20 gaging stations that have active-channel widths ranging from 14 to 240 feet and average bankfull-channel depths ranging from 2.5 to 9.2 feet. Channel-geometry characteristics also were measured at 168 ungaged sites to provide information that can be used to better define the geographic-area boundaries in three areas of Ohio where the boundaries were previously defined in a flood magnitude and frequency report.

Water-Resources Investigations Report↗
USGS1996

Results of ground-water tracer tests using tritiated water at Oak Ridge National Laboratory, Tennessee

Ground-water tracer tests were conducted at two sites in the radioactive-waste disposal area of Oak Ridge National Laboratory from 1977 to 1982. The purpose of the tests was to determine if the regolith beds had weathered sufficiently to permit the substantial flow of water across them. Regolith of the sites has developed on the Pumpkin Valley Shale and the Nolichucky Shale of the Conasauga Group, both of Cambrian age. About 50 curies of tritium dissolved in water were used as the tracer at one site, and about 100 curies at the other. Distances from the injection wells to a semi-circle of observation wells were 12 and 30 feet, respectively. Results demonstrated that ground water is able to flow through joints in the weathered bedding and that the direction of the water-table gradient is the primary factor governing flow direction. Nevertheless, the substantial lateral spread of the plume as it developed showed that bedding-plane openings, important in controlling flow in the deeper rock, can still exert a significant secondary influence on flow direction in the weathered rock. About 3,500 water samples from the injection and observation wells were analyzed for tritium during the test period. Concentrations detected spanned 11 orders of magnitude. Measurable concentrations were still present in the two injection wells and most observation wells 5 years after the tracer was introduced. Matrix diffusion may have played a significant role in these tests. The process would account for the sustained concentrations of tritium at many of the observation wells, the long-term residual concentrations at the injection and observation wells, and the apparent slow movement of the centers of mass across the two well fields. The process also would have implications regarding aquifer remediation. Other tracer tests have been conducted in the regolith of the Conasauga Group. Results differ from the results described in this report.

Tennessee↗
USGS1997

Occurrence of nitrate, pesticides, and volatile organic compounds in the Kirkwood-Cohansey aquifer system, southern New Jersey

Water samples were collected from a network of 72 shallow monitoring wells to assess the chemical quality of recently recharged ground water in the surficial Kirkwood- Cohansey aquifer system of southern New Jersey. The wells are randomly distributed among agricultural, urban, and undeveloped areas to provide data representative of chemical conditions of ground water underlying each of these land-use settings. Samples were analyzed for nutrients, pesticides, and volatile organic compounds (VOC's). Concentrations of nitrate were highest in agricultural areas, where the U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Level (MCL) of 10 mg/L (milligrams per liter) as nitrogen was exceeded in 60 percent of the samples. Concentrations of nitrate were intermediate in urban areas, where the 10-mg/L concentration was exceeded in only 1 of 44 samples. All concentrations in samples from undeveloped areas were less than 1.0 mg/L. Pesticides and VOC's were frequently detected; however, concentrations were low and rarely exceeded established or proposed USEPA or N.J. Department of Environmental Protection (NJDEP) drinking-water regulations. With the exception of the agricultural pesticide dinoseb, established regulations are at least 2.9 times the maximum concentration for pesticides and at least 5 times the maximum concentration for VOC's reported in the samples from the 72-well network. Investigations by the U.S. Geological Survey (USGS) are ongoing in southern New Jersey to evaluate the (1) presence and concentration of pesticide-degradation byproducts in shallow ground water; (2) presence and movement of nitrate, pesticides, and VOC's in the atmosphere, streams, unsaturated zone, and aquifers; (3) transport and fate of these compounds as they migrate deeper into the aquifer system; and (4) implications of these findings for the integrity of the regional water supply.

New Jersey↗
USGS1952

Coal investigations in the Homer district, Kenai coal field, Alaska, in 1950 and 1951

This report presents the results of work done in the last three weeks of the 1950 field season and in all of the 1951 season, and supplements reports by Barnes (19149) and Cobb (1950, 1951). Barnes' report covers investigations of coal-bearing rocks of the Tertiary Kenai formation in a coastal belt between Bluff Point and the head of Kachemak Bay (pl. 2). Cobb's reports deal with similar rocks exposed along the coast between Bluff Point and the beach bluffs about 7 miles south of the village of Cohoe, and in the lower reaches of the Ninilchik River valley. The present report covers extensions of previous mapping in the valleys of Deep Creek and the Anchor River, and on high land between the area covered by Barnes' report and the Anchor River valley. The results of ground and aerial reconnaissance of most of the Homer district also are presented. The writer, assisted by F. J. Markewioz, carried on the field work which is the basis for this report, between August 13 mad September 6, 1950, and between May 10 and August 30, 1951. Field work included traverses along Deep Creek and the Anchor River, and between the southeast end of Tustumena Lake and the head of Kachemak Bay. It included also the detailed measurement and tracing of coal beds on the upland north and northwest of Homer, sampling of coal beds along the northwest shore of Kachemak Bay and the southeast shore of Cook Inlet, and both ground and aerial reconnaissance of the rest of the Homer district and adjoining areas. The writer is indebted to James W. Scott, Forester, U. S. Bureau of Land Management, Lomer, Alaska, who accompanied him on a traverse from Tustumena Lake to Kaohemak Bay and assisted at many other times during the 1950 and 1951 field seasons. Ralph Gaetano and Thomas Shelford of Homer were of great assistance in locating and reaching isolated outcrops of coal-bearing rooks. Daniel B. Krinsley, of the Alaska Terrain and Permafrost Section of the U. S. Geological Survey, has generously made available the results of many of his observations in remote parts of the Homer district which could not be visited by the writer.

Alaska↗
USGS2012

Investigations at active volcanoes

The field of volcanology has expanded greatly in the years 1967–1970, and work on active volcanoes has kept pace with this expansion. I have restricted this summary and the accompanying bibliography to studies by U.S.‐based investigators of active or potentially active volcanoes. I have been immeasurably aided in writing this summary by communications from R. Citron of the Smithsonian Institution Center for Short‐Lived Phenomena, W. Melson and T. Simkin of the Smithsonian Institution, A. McBirney of the Center for Volcanology, University of Oregon, R.B. Forbes of the University of Alaska, and R.W. Decker of Dartmouth College.

Eos, Transactions, American Geophysical Union↗
USGS2025

Estimated hydrogeologic, spatial, and temporal distribution of self-supplied domestic groundwater withdrawals for aquifers of the Virginia Coastal Plain

Water use from private-domestic wells accounts for nearly 40 percent of total groundwater withdrawals in the Virginia Coastal Plain Physiographic Province (henceforth called the Virginia Coastal Plain). However, because self-supplied domestic water use generally falls below the Virginia Department of Environmental Quality (VDEQ) reporting and management threshold of 300,000 gallons per month, quantifying these withdrawals is challenging. This report builds upon the foundation of previous U.S. Geological Survey investigations by providing revised techniques to improve estimates of the aquifer source, spatial distribution, and monthly magnitude of these groundwater withdrawals. The aquifer sources of private-domestic wells in the Virginia Coastal Plain were estimated by cross-referencing 8,264 well records from the VDEQ and the Virginia Department of Health to a digital model of the Virginia Coastal Plain hydrogeologic framework. This analysis highlights the regional importance of the Yorktown-Eastover, Potomac, and surficial aquifers. Collectively, these three aquifers account for 80 percent of self-supplied domestic groundwater withdrawals. The population using self-supplied domestic water was estimated using census blocks, well-use ratios, building footprints, and land-use and land-cover data to produce a high-resolution, disaggregated, raster-based dataset. This approach improves upon previous models at the census-block or road-network scale by reducing the low-density spread of the self-supplied domestic population across undeveloped areas and concentrating the population and its corresponding water use in the areas where it is most likely to occur. Results show that an estimated 475,332 people comprise the 2020 self-supplied domestic population of the Virginia Coastal Plain, an increase of 5.7 percent since 2010, and the greatest concentrations of self-supplied domestic population surround large cities. Estimates could be further refined with the addition of current and complete spatial data on public water-system service areas. The quantity of water used by the self-supplied domestic population was estimated by modifying published state per-capita water-use coefficients with the corresponding monthly variability assessed from Virginia Coastal Plain public water-system withdrawal data. This analysis estimates an average increase of 12 percent from June through August and an average decrease of 8 percent from December through March from the baseline annual average of 80 gallons per day per capita, which generally matches similar studies in the eastern United States. The application of these revised methodologies for the estimation of private-domestic wells and the self-supplied domestic population improves understanding of domestic groundwater use in the Virginia Coastal Plain across hydrogeologic, spatial, and temporal scales. These revisions help better inform water-resource managers and decision makers and support higher resolution groundwater modeling. Furthermore, these methods are transferrable to other areas where self-supplied domestic water withdrawals are important to the overall water budget.

Virginia↗
USGS2001

Source identification and fish exposure for polychlorinated biphenyls using congener analysis from passive water samplers in the Millers River Basin, Massachusetts

Measurements of elevated concentrations of polychlorinated biphenyls (PCBs) in fish and in streambed sediments of the Millers River Basin, Massachusetts and New Hampshire, have been reported without evidence of the PCB source. In 1999, an investigation was initiated to determine the source(s) of the elevated PCB concentrations observed in fish and to establish the extent of fish exposure to PCBs along the entire main stems of the Millers River and one of its tributaries, the Otter River. Passive samplers deployed for 2-week intervals in the water-column at 3 1 stations, during summer and fall 1999, were used to assess PCB concentrations in the Millers River Basin. The samplers concentrate PCBs, which diffuse from the water column through a polyethylene membrane to hexane (0.200 liters) contained inside the samplers. Only dissolved PCBs (likely equivalent to the bioavailable fraction) are subject to diffusion through the membrane. The summed concentrations of all targeted PCB congeners (summed PCB) retrieved from the samplers ranged from 1 to 8,000 nanograms per hexane sample. Concentration and congener-pattern comparisons indicated that the historical release of PCBs in the Millers River Basin likely occurred on the Otter River at the upstream margin of Baldwinville, Mass. Elevated water-column concentrations measured in a wetland reach on the Otter River downstream from Baldwinville were compatible with a conceptual model for a present-day (1999) source in streambed sediments, to which the PCBs partitioned after their original introduction into the Otter River and from which PCBs are released to the water now that the original discharge has ceased or greatly decreased. Two four-fold decreases in summed PCB concentrations in the Millers River, by comparison with the highest concentration on the Otter River, likely were caused by (1) dilution with water from the relatively uncontaminated upstream Millers River and (2) volatilization of PCBs from the Millers River in steep-gradient reaches. A relatively constant concentration of summed PCBs in the reach of the Millers River from river mile 20 to river mile 10 was likely a consequence of a balance between decreased volatilization rates in that relatively low-gradient reach and resupply of PCBs to the water column from contaminated streambed sediments. A second high-gradient reach from river mile 10 to the confluence of the Millers River with the Connecticut River also was associated with a decrease in concentration of water-column summed PCBs. Volatilization as a loss mechanism was supported by evidence in the form of slight changes of the congener pattern in the reaches where decreases occurred. Exposure of fish food webs to concentrations of dissolved PCBs exceeded the U.S. Environmental Protection Agency's water-quality criterion for PCBs throughout most of the Millers River and Otter River main stems. Because the apparent source of PCBs discharged was upstream on the Otter River, a large number of river miles downstream (more than 30 mi) had summer water-column PCB concentrations that would likely lead to high concentrations of PCBs in fish.

Massachusetts↗
USGS2002

Glacial geology and aquifer characteristics of the Big River area, central Rhode Island

The Rhode Island Water Resources Board (RIWRB), which is responsible for developing the State's major water resources, is concerned that continued growth in demand for water in Rhode Island will severely stress water supplies. In the early 1960s, the State proposed construction of a surface-water reservoir in the Big River Basin in central Rhode Island to meet the growing water demands, but, to date (2001) the U.S. Environmental Protection Agency has not given approval for construction of this reservoir. As an alternative, the RIWRB would like to identify sites in the Big River area stream-aquifer system where high-yield supply wells can be constructed to meet future water demands. A cooperative study was initiated during the summer of 1995 by the U.S. Geological Survey (USGS) and the RIWRB to evaluate ground water as a source of water supply in the Big River area. This report presents the initial results of a multi-year investigation of the three-dimensional characteristics of the surficial aquifer system based on geologic and geophysical field studies, and provides information needed to protect, develop, and manage the Big River area stream-aquifer system. The Big River area includes the entire Big River drainage basin and part of the Mishnock River drainage basin (fig. 1) and covers approximately 35 mi2, including parts of the towns of Coventry, Exeter, and West Greenwich. Most of the Big River area is in Kent County, with a small part in Washington County; it encompasses parts of the Coventry Center, Hope Valley, Crompton, and Slocum 7.5-minute quadrangles. This investigation includes a characterization of the geologic framework and an evaluation of the hydraulic properties of the stream-aquifer system. The Big River area stream-aquifer system is the surficial aquifer and the network of rivers, brooks, lakes, and ponds that overlie and are in hydraulic connection with the aquifer. The surficial materials units of the Big River area and the accompanying bedrock-surface contours (pl. 1) were delineated on the basis of data collected during field mapping, seismic-refraction surveys, ground-penetrating radar surveys, logs from all available wells and test holes, and results of previous investigations. Some streams in the study area lose surface water naturally to the underlying sand and gravel aquifer, whereas others lose water to the aquifer by induced infiltration of streamflow caused by ground-water withdrawals. Most large ground-water withdrawals are from public-supply wells in the sand and gravel aquifer in the Mishnock River Basin. Minimal ground-water withdrawals take place in the Big River Basin, because most of the land is designated as open space and protected from development by State law. The primary use of surface water in the study area is for recreation. Water from the Flat River Reservoir, the largest surface-water body in the study area, is used only for recreational purposes.

Rhode Island↗
USGS2007

Magnitude and Frequency of Floods in Alabama, 2003

Methods of estimating flood magnitudes for recurrence intervals of 1.5, 2, 5, 10, 25, 50, 100, 200, and 500 years have been developed for rural streams in Alabama that are not affected by regulation or urbanization. Regression relations were developed using generalized least-squares regression techniques to estimate flood magnitude and frequency on ungaged streams as a function of the basin drainage area. These methods are based on flood-frequency characteristics for 169 gaging stations in Alabama and 47 gaging stations in adjacent states having 10 or more years of record through September 2003. Graphical relations of peak flows to drainage areas are presented for sites along the Alabama, Coosa, Tallapoosa, Tennessee, Tombigbee, and Black Warrior Rivers. Equations that account for drainage area and percentage of impervious cover as independent variables also are provided for estimating flood magnitudes on ungaged urban streams (taken from a previous report).

Scientific Investigations Report↗