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The Colorado Plateau geologic studies comprise a number of geologic mapping and specialized geologic studies of the pre-Morrison (mainly Triassic) and Morrison uranium-bearing formations.
Ninety-six maps depicting the spatial variation of the depth-duration frequency of precipitation annual maxima for Texas are presented. The recurrence intervals represented are 2, 5, 10, 25, 50, 100, 250, and 500 years. The storm durations represented are 15 and 30 minutes; 1, 2, 3, 6, and 12 hours; and 1, 2, 3, 5, and 7 days. The maps were derived using geographically referenced parameter maps of probability distributions used in previously published research by the U.S. Geological Survey to model the magnitude and frequency of precipitation annual maxima for Texas. The maps in this report apply that research and update depth-duration frequency of precipitation maps available in earlier studies done by the National Weather Service.
Shawnee Mission Lake is an artificial impoundment central to Shawnee Mission Park, the largest public park in Johnson County, Kansas. The Shawnee Mission Lake watershed has remained relatively undeveloped since the completion of the dam in 1962. However, recent (1990?2006) urban development has been a cause for concern regarding the quantity and quality of sediment entering the reservoir. The U.S. Geological Survey collected two cores of bottom sediment to assess sediment accumulation and quality in Shawnee Mission Lake. Results from this study indicate that sediment accumulation has remained relatively constant from 1970?2006 at the downstream portion of the reservoir. Runoff from urban portions of the watershed are likely responsible for larger concentrations of selected trace elements in more recently deposited reservoir sediment. Information provided in this report can be used by Johnson County officials to help determine the current and future recreational capacity of the lake.
This report documents selected age data interpreted from measured concentrations of environmental tracers in groundwater from 1,399 National Water-Quality Assessment (NAWQA) Program groundwater sites across the United States. The tracers of interest were chlorofluorocarbons (CFCs), sulfur hexafluoride (SF 6 ), and tritium/helium-3 ( 3 H/ 3 He). Tracer data compiled for this analysis primarily were from wells representing two types of NAWQA groundwater studies—Land-Use Studies (shallow wells, usually monitoring wells, in recharge areas under dominant land-use settings) and Major-Aquifer Studies (wells, usually domestic supply wells, in principal aquifers and representing the shallow, used resource). Reference wells (wells representing groundwater minimally impacted by anthropogenic activities) associated with Land-Use Studies also were included. Tracer samples were collected between 1992 and 2005, although two networks sampled from 2006 to 2007 were included because of network-specific needs. Tracer data from other NAWQA Program components (Flow System Studies, which are assessments of processes and trends along groundwater flow paths, and various topical studies) were not compiled herein. Tracer data from NAWQA Land-Use Studies and Major-Aquifer Studies that previously had been interpreted and published are compiled herein (as piston-flow ages), but have not been reinterpreted. Tracer data that previously had not been interpreted and published are evaluated using documented methods and compiled with aqueous concentrations, equivalent atmospheric concentrations (for CFCs and SF 6 ), estimates of tracer-based piston-flow ages, and selected ancillary data, such as redox indicators, well construction, and major dissolved gases (N 2 , O 2 , Ar, CH 4 , and CO 2 ). Tracer-based piston-flow ages documented in this report are simplistic representations of the tracer data. Tracer-based piston-flow ages are a convenient means of conceptualizing groundwater age. However, the piston-flow model is based on the potentially limiting assumptions that tracer transport is advective and that no mixing occurs. Additional uncertainties can arise from tracer degradation, sorption, contamination, or fractionation; terrigenic (natural) sources of tracers; spatially variable atmospheric tracer concentrations; and incomplete understanding of mechanisms of recharge or of the conditions under which atmospheric tracers were partitioned to recharge. The effects of some of these uncertainties are considered herein. For example, degradation, contamination, or fractionation often can be identified or inferred. However, detailed analysis of the effects of such uncertainties on the tracer-based piston-flow ages is constrained by sparse data and an absence of complementary lines of evidence, such as detailed solute transport simulations. Thus, the tracer-based piston-flow ages compiled in this report represent only an initial interpretation of the tracer data.
In January 2014, a storage tank leaked, spilling a large quantity of 4-methylcyclohexane methanol into the Elk River in West Virginia and contaminating the water supply for more than 300,000 people. In response, the West Virginia Legislature passed Senate Bill 373, which requires the West Virginia Department of Health and Human Resources (WVDHHR) to assess the susceptibility and vulnerability of public surface-water-influenced groundwater supply sources (SWIGS) and surface-water intakes statewide. In response to this mandate for reassessing SWIGS statewide, the U.S. Geological Survey (USGS), in cooperation with the WVDHHR, Bureau of Public Health, Office of Environmental Health Services, compiled available data and summarized the results of previous groundwater studies to provide the WVDHHR with data that could be used as part of the process for assessing and determining SWIGS. Existing geologic, hydrologic, well-construction, water-quality, and other related data and information from previous U.S. Geological Survey (USGS) hydrogeologic studies and the USGS National Water Information System (NWIS) database, in conjunction with data from the West Virginia Bureau for Public Health (WVBPH) Department of Health and Human Resources (WVDHHR) and the West Virginia Department of Environmental Protection database and files, were collected, compiled, and analyzed to help the WVDHHR to better assess public groundwater supply wells that may meet the definition of a surface-water-influenced- groundwater supply (SWIGS). In this study, measures of intrinsic susceptibility, which are characterized by the physical properties that affect the ease with which water moves through the unsaturated zone and, subsequently, into the saturated zone within an aquifer, showed that karst limestone aquifers are the aquifers most intrinsically susceptible to contamination within the State of West Virginia. Karst limestone aquifers are present within Cambrian- and Ordovician-age formations within West Virginia’s eastern panhandle and in Mississippian-age limestones within the Greenbrier River valley. Solution development within these limestone aquifers allows rapid recharge and flow of groundwater within the aquifer, both of which allow surface contaminants to easily enter the aquifer and travel long distances in a short period of time. Alluvial aquifers bordering the Ohio River in western West Virginia are also potentially highly susceptible to contamination because these alluvial aquifers can receive significant recharge from the adjacent Ohio River. Any potential contaminants that may be present in the river have the potential to enter the aquifer and contaminate wells completed within the sand and gravel alluvial sediments within which the wells are completed. These same alluvial sediments, however, help to retard the movement of bacteria and other potentially pathogenic organisms, such as Cryptosporidia and Giardia lamblia , into the aquifer. As a result, samples from alluvial aquifers bordering the Ohio River and elsewhere within the State do not commonly test positive for indicator bacteria, such as total coliform, fecal coliform, or Escherichia coli ( E. coli ). The alluvial sediments do not, however, provide assimilative capacity with respect to water soluble compounds such as nitrate and certain volatile and semi-volatile organic compounds. Therefore, the Ohio River alluvial aquifers are highly susceptible to organic compounds present in the river or on the land surface near a well. These aquifers are also susceptible to nitrate contamination from fertilizers, pesticides, and manure, which are commonly used on the fertile agricultural soils present on terraces along the Ohio River. Abandoned-coal-mine aquifers, which are typically used as a source of groundwater in southern West Virginia, are moderately susceptible to contamination. The vast network of voids from mine entries provide vast storage for groundwater in abandoned mine aquifers, and fracturing of overburden strata, which is common in areas of past or current mining, can allow rapid infiltration of contaminants to the aquifer. Where streams cross over below-drainage underground coal mines, there is an increased potential for contamination of coal-mine aquifers. As a result, above-drainage underground coal mines, those mines that are present at an elevation above local tributary drainage, are probably less susceptible to contamination than are below-drainage underground coal mines. Public groundwater supplies in abandoned coal mines need to be evaluated on a case-by-case basis to assess the potential for recharge of contaminated surface water to enter below-drainage underground coal-mine aquifers and to assess potential hydraulic conductivity to nearby surface-water bodies, such as lakes, ponds, rivers, or streams. Fractured-rock aquifers compose an additional major type of aquifer within the State of West Virginia. Owing to their low permeability and their typically small groundwater capture areas, fractured-rock aquifers within the State of West Virginia typically have low susceptibility to contamination. However, there are exceptions, and wells completed in fractured-rock aquifers that are in close proximity to streams may be adversely affected by induced recharge from the stream. Where such systems are present, frequent bacterial testing of the source water can be used to ascertain the potential for microbial contamination of the aquifer. Intrinsic susceptibility alone does not fully predict whether or not a well is vulnerable to contamination, only that the hydrogeologic terrain is suitable for rapid transport of pathogenic organisms or chemical compounds to and within the aquifer. However, contaminants may or may not be present in the recharge water to an individual well or well field. Therefore, an assessment of potential contaminant sources, such as nearby gas wells, landfills, underground storage tanks, above ground storage tanks, major transportation corridors, surface or underground coal mines, and flood plains, is needed to assess vulnerability. The assessments need to be conducted on a case-by-case basis or, as has been done in this study, by collecting and compiling the number of potential contaminant sources that may be present in the source-water-protection area for an individual public groundwater supply source. Groundwater public-supply systems in areas of high intrinsic susceptibility and with a large number of potential contaminant sources within the recharge or source-water-protection area of individual wells or well fields are potentially vulnerable to contamination and probably warrant further evaluation as potential SWIGS. However, measures can be taken to educate the local population and initiate safety protocols and protective strategies to appropriately manage contaminant sources to prevent release of contaminants to the aquifer, therefore, reducing vulnerability of these systems to contamination. However, each public groundwater supply source needs to be assessed on an individual basis. Data presented in this report can be used to categorize and prioritize wells and springs that have a high potential for intrinsic susceptibility or vulnerability to contamination.
Hydrocarbon wells are not active forever; when they become permanently disused (abandoned), well infrastructure must be remediated or repurposed. Knowing which wells are abandoned is the initial and often complicated step in taking responsibility for well infrastructure. Each State creates laws and regulates hydrocarbon operations, which includes well abandonment. The existence of multiple regulating authorities means definitions of abandonment are mostly found in legal documents are broadly defined or other terms are used. This report presents a technical approach to defining hydrocarbon well abandonment using well production data and identifies abandoned hydrocarbon wells using the new definition.
Tinian, which lies in the western Pacific Ocean at latitude 15°N and longitude 145°W (fig. 1), is the second largest island (39.2 mi 2 ) in the Commonwealth of the Northern Mariana Islands (CNMI). Fresh ground water is obtained from shallow wells that tap the surface of a freshwater lends found in an aquifer composed mainly of coralline limestone. The main water-supply well withdraws water with a chloride concentration ranging from 160 to 220 mg/L. Current (1999) pumping rates adequately supply the island residents but future demand are expected to be higher.. To better understand the ground-water resources of the island and to learn more about the hydrology of oceanic islands, the U.S. Geological Survey (USGS) entered into a cooperative study with the Municipality of Tinian. The objective of the study, conducted between 1990 and 1997, was to assess the ground-water resources of the is;land. This report presents some of the results of the study including a description of the island's geology and geography, the current land use, the water-production system, the thickness and arcal extent of the freshwater lens, the water-table configuration and directions of ground-water flow. The report also discusses the relation of the changes in water-table elevation to daily and seasonal changes in ocean level.
The Ogallala Formation and associated Tertiary and Quarternary deposits form the principal aquifers supporting irrigation in the High Plains of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. The volume of water in storage within the aquifers is declining in most of the High Plains because water is being withdrawn in excess of the rate of replenishment. The U.S. Geological Survey has initiated a 5-year study of the High Plains aquifer system to develop the geohydrologic data base and computer models of the ground-water flow system needed to evaluate the response of the aquifer,system to ground-water management alternatives. This report describes the objectives, plan, and organization of the study and outlines the work to be accomplished in each state in the study area.
Flow-stratification patterns were observed in Gulf Island Pond during time-of-travel studies in May and August 1980. The stratification patterns in this 70 million cubic-meter impoundment were due to a temperature differences between inflowing water and reservoir water. Separation was observed at temperature differences of 0.5 degrees C in May 1980 and 1.0 degrees C in August 1980. The pathway taken by inflowing water through the reservoir was governed by the temperature-related density forces acting between the two water masses. Data collected during August 1980 to define differences in dye concentrations with depth at two fixed profile points in Gulf Island Pond showed average water velocity to be seven times faster near the bottom than near the surface. A concept of mass flow was used to analyze data collected at sites downstream from Gulf Island Dam where flow varied rapidly with time. This report presents the mathematical derivation of controid traveltime, skewness, and percentage recovery of dye mass as determined from mass versus time curves. (USGS)
By 1990, sanitary sewers in Nassau County Sewage Disposal Districts 2 and 3 and Suffolk County Southwest Sewer District will discharge to the ocean 140 cu ft of water/sec that would otherwise be returned to the groundwater system through septic tanks and similar systems. To evaluate the effects of this loss on groundwater levels and streamflow, the U.S. Geological Survey developed a groundwater flow model that couples a fine-scale subregional model to a regional model of larger scale. The regional model generates flux boundary conditions for the subregional model, and the subregional model provides detail in the area of concern. Results indicate that the water table will decline by as much as 8 ft along the Suffolk-Nassau county line, with effects decreasing eastward. Base flow is predicted to decrease by as much as 73% in a stream along the county line, but this effect will decrease to zero just east of the sewered area. This report is one of a series describing the predicted hydrologic effects of sewers in southern Nassau and southwest Suffolk Counties. (USGS)
Primary productivity by phytoplankton was measured on samples collected from the Potomac Tidal River, Maryland. The studies were performed monthly from May 1980 to September 1981. Additional studies were done once a week in August 1980, twice a week from August 4 to 8, 1980 and twice in September 1980. Depth-integrated samples were collected at five stations and incubated in boxes that were exposed to natural sunlight. The boxes were covered with neutral density filters transmitting 100 , 65, 32, 16, and 6 percent surface light. River water was pumped continuously over the samples. The extinction of light in the water column by phytoplankton was measured when samples were collected. Experiments were performed to select a method for routine productivity analysis. No difference was found between productivity: (1) determined in situ and in boxes; (2) measured in 300 ml and (4) calculated from short term (4 hours) and long term (10-24 hours) incubations. There were higher productivity differences in samples that were rotated among different light intensities every 15 minutes (simulating mixing) than those remaining stationary. Respiration was significantly less in samples pumped through a hose from those collected using a depth-integrating sampler. Depth-integrated primary productivity was determined from the productivity data using an equation modified from one reported in the literature. Depth-integrated gross primary productivity was highest in August 1980 and 1981 and lowest in January 1980. (USGS)
Detailed maps of the thickness of the Jackson-upper Claiborne confining unit and the altitude of the water table in the alluvium and fluvial deposits provide much new information concerning areas where downward leakage is or may be occurring from the water-table aquifers to the Memphis aquifer in the Memphis area. A detailed map of the altitude of the potentiometric surface of the Memphis aquifer and the locations of 44 sites where contaminants have been detected in the water-table aquifers indicate that many of these sites are located in areas where the direction of ground-water flow in the Memphis aquifer is toward municipal well fields. Consequently, if contaminants enter the Memphis aquifer, a hydraulic potential exists for their transport to those wellfields. Recently (1986-88), volatile organic compounds were detected in water from five municipal wells screened in the Memphis aquifer - three in the Allen well field of the Memphis Light, Gas and Water Division at Memphis and two in the west well field at Collierville. Concentrations of seven volatile organic compounds totaled about 11 micrograms per liter in a sample from one well in the Allen wellfield at Memphis, and the concentration of one compound was 25 micrograms per liter in a sample from one well at Collierville. These are the first reported occurrences of synthetic organic compounds in the Memphis aquifer and prove that the principal aquifer in the Memphis area is vulnerable to contamination.
Specific yield and specific retention are aquifer characteristics that are important in determining the volume of water in storage in an aquifer. These characteristics can be determined by laboratory analyses of undisturbed samples of aquifer material. However. quicker, less costly alternatives to these laboratory analyses are needed. This report presents techniques for estimating specific yield and specific retention based on grain-size analyses, and based on interpretation of borehole geophysical logs.
This report draws on previous syntheses and basic research studies of sedimentary exhalative (sedex) deposits to arrive at the defining criteria, both descriptive and genetic, for sedex-type deposits. Studies of the tectonic, sedimentary, and fluid evolution of modern and ancient sedimentary basins have also been used to select defining criteria. The focus here is on the geologic characteristics of sedex deposit-hosting basins that contain greater than 10 million metric tons of zinc and lead. The enormous size of sedex deposits strongly suggests that basin-scale geologic processes are involved in their formation. It follows that mass balance constraints of basinal processes can provide a conceptual underpinning for the evaluation of potential ore-forming mechanisms and the identification of geologic indicators for ore potential in specific sedimentary basins. Empirical data and a genetic understanding of the physicochemical, geologic, and mass balance conditions required for each of these elements are used to establish a hierarchy of quantifiable geologic criteria that can be used in U.S. Geological Survey national assessments. In addition, this report also provides a comprehensive evaluation of environmental considerations associated with the mining of sedex deposits.
Analytical results for arsenic in water samples from 5,023 wells obtained during 1969–2007 across Pennsylvania were compiled and related to other associated groundwater-quality and environmental factors and used to predict the probability of elevated arsenic concentrations, defined as greater than or equal to 4.0 micrograms per liter (µg/L), in groundwater. Arsenic concentrations of 4.0 µg/L or greater (elevated concentrations) were detected in 18 percent of samples across Pennsylvania; 8 percent of samples had concentrations that equaled or exceeded the U.S. Environmental Protection Agency’s drinking-water maximum contaminant level of 10.0 µg/L. The highest arsenic concentration was 490.0 µg/L. Comparison of arsenic concentrations in Pennsylvania groundwater by physiographic province indicates that the Central Lowland physiographic province had the highest median arsenic concentration (4.5 µg/L) and the highest percentage of sample records with arsenic concentrations greater than or equal to 4.0 µg/L (59 percent) and greater than or equal to 10.0 µg/L (43 percent). Evaluation of four major aquifer types (carbonate, crystalline, siliciclastic, and surficial) in Pennsylvania showed that all types had median arsenic concentrations less than 4.0 µg/L, and the highest arsenic concentration (490.0 µg/L) was in a siliciclastic aquifer. The siliciclastic and surficial aquifers had the highest percentage of sample records with arsenic concentrations greater than or equal to 4.0 µg/L and 10.0 µg/L. Elevated arsenic concentrations were associated with low pH (less than or equal to 4.0), high pH (greater than or equal to 8.0), or reducing conditions. For waters classified as anoxic (405 samples), 20 percent of sampled wells contained water with elevated concentrations of arsenic; for waters classified as oxic (1,530 samples) only 10 percent of sampled wells contained water with elevated arsenic concentrations. Nevertheless, regardless of the reduction-oxidation classification, 54 percent of samples with low pH (13 of 24 samples) and 25 percent of samples with high pH (57 of 230 samples) had elevated arsenic concentrations. Arsenic concentrations in groundwater in Pennsylvania were correlated with concentrations of several chemical constituents or properties, including (1) constituents associated with redox processes, (2) constituents that may have a similar origin or be mobilized under similar chemical conditions as arsenic, and (3) anions or oxyanions that have similar sorption behavior or compete for sorption sites on iron oxides. Logistic regression models were created to predict and map the probability of elevated arsenic concentrations in groundwater statewide in Pennsylvania and in three intrastate regions to further improve predictions for those three regions (glacial aquifer system, Gettysburg Basin, Newark Basin). Although the Pennsylvania and regional predictive models retained some different variables, they have common characteristics that can be grouped by (1) geologic and soils variables describing arsenic sources and mobilizers, (2) geochemical variables describing the geochemical environment of the groundwater, and (3) locally specific variables that are unique to each of the three regions studied and not applicable to statewide analysis. Maps of Pennsylvania and the three intrastate regions were produced that illustrate that areas most at risk are those with geology and soils capable of functioning as an arsenic source or mobilizer and geochemical groundwater conditions able to facilitate redox reactions. The models have limitations because they may not characterize areas that have localized controls on arsenic mobility. The probability maps associated with this report are intended for regional-scale use and may not be accurate for use at the field scale or when considering individual wells.
The U.S. Geological Survey, in cooperation with the Montana Department of Environmental Quality and the Montana Department of Natural Resources and Conservation, developed regional regression equations based on basin and streamflow characteristics for streamflow-gaging stations through water year 2009 that can be used to estimate streamflow characteristics for ungaged sites in western Montana. The regression equations allow estimation of low-flow frequencies; mean annual and mean monthly streamflows; and the 20-, 50-, and 80-percent durations for annual and monthly duration streamflows for ungaged sites in western Montana that are unaffected by regulation. Regression equations were developed for 54 streamflow characteristics in each of the 4 hydrologic regions generally located in western Montana. Exploratory data analyses determined that of the 40 basin characteristics used as explanatory variables, only 3 were significant in the final equations. These three basin characteristics are contributing drainage area, mean annual precipitation of the drainage basin, and percentage of basin with slopes greater than 50 percent. Low-flow frequency data and daily mean streamflow data from 152 streamflow-gaging stations were used to develop the regression equations. These 152 streamflow-gaging stations were considered to be unregulated (or only the unregulated period of record for regulated streamflow-gaging stations were used). For this study, a streamflow-gaging station is considered to be unregulated if cumulative drainage area upstream from all upstream dams is less than 20 percent of the drainage basin for the streamflow-gaging station, and if no large diversion canals are upstream from the streamflow-gaging station. In addition to the regional regression equations, two methods for estimating streamflow characteristics based on drainage areas of a nearby streamflow-gaging station are provided. Also, spreadsheet tools are provided for calculating streamflow characteristics based on regression equations or the drainage-area ratio method. All of the data used to calculate basin characteristics were derived from publicly available data sources and are available through the U.S. Geological Survey Streamstats program ( http://water.usgs.gov/osw/streamstats/ ) for Montana. The primary purpose of the Montana StreamStats application is to provide estimates of basin characteristics and streamflow characteristics for user-selected ungaged sites on Montana streams. The regional regression equations presented in this report have been loaded to the Montana StreamStats application and can be used to derive streamflow characteristics for ungaged sites.
Since 2002, the Woods Hole Coastal and Marine Science Center Samples Repository has been supporting U.S. Geological Survey research by providing secure storage for geological, geochemical, and biological samples, organizing and actively inventorying these sample collections, and providing researchers access to these scientific collections for study and reuse. Over the years, storage facilities have changed, and new collections management strategies have been adapted as sample collections have grown and as research programs and focuses have shifted. The commitment of the samples repository to preserve and provide physical samples for future research, however, has remained the same. This report documents the collections management plan developed and implemented by the Woods Hole Coastal and Marine Science Center Samples Repository to manage the center’s scientific collections.
Two interagency workshops were held in 2019 and 2023 in Fort Collins, Colorado, to discuss the use of novel data in recreation monitoring. During the workshops, the phrase “novel data in recreation monitoring” was primarily used to refer to data from social media, mobile device applications, and other online secondary sources. The goals of these workshops were to share information across agencies and researchers on the state of the science and applications for using novel data and to collectively discuss best practices for using novel data for understanding recreation on public lands and waters. Presentations during the workshops focused on use-cases, current applications, and the current state of research (as of the time of the workshops) for using novel data in recreation monitoring. Group discussions during the workshops focused on the strengths and limitations of novel data sources, potential approaches for integrating new and emerging data sources and methods with traditional approaches, and research and management needs. This report provides the proceedings of the 2019 and 2023 interagency workshops on novel data in recreation monitoring.