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At least 271 records · Page 15Linked to original sources
USGS1967

Effects of the earthquake of March 27, 1964, at Seward, Alaska

Seward, in south-central Alaska, was one of the towns most devastated by the Alaska earthquake of March 27, 1964. The greater part of Seward is built on an alluvial fan-delta near the head of Resurrection Bay on the southeast coast of the Kenai Peninsula. It is one of the few ports in south-central Alaska that is ice free all year, and the town’s economy is almost entirely dependent upon its port facilities. The Alaska earthquake of March 27, 1964, magnitude approximately 8.3–8.4, began at 6:36 p.m. Its epicenter was in the northern part of the Prince William Sound area; focal depth was 20–50 km. Strong ground motion at Seward lasted 3–4 minutes. During the shaking, a strip of land 50–400 feet wide along the Seward waterfront, together with docks and other harbor facilities, slid into Resurrection Bay as a result of large-scale submarine landsliding. Fractures ruptured the ground for'severa1 hundred feet back from the landslide scarps. Additional ground was fractured in the Forest Acres subdivision and on the alluvial floor of the Resurrection River valley; fountaining and sand boils accompanied the ground fracturing. Slide-generated wares, possibly seiche waves, and seismic sea waves crashed onto shore; ware runup was as much as 30 feet above mean lower low water and caused tremendous damage; fire from burning oil tanks added to the destruction. Damage from strong ground motion itself was comparatively minor. Tectonic subsidence of about 3.6 feet resulted in low areas being inundated at high tide. Thirteen people were killed and five were injured as a result of the earthquake. Eighty-six houses were totally destroyed and 260 were heavily damaged. The harbor facilities were almost completely destroyed, and the entire economic base of the town was wiped out. The total cost to replace the destroyed public and private facilities was estimated at $22 million. Seward lies on the axis of the Chugach Mountains geosyncline. The main structural trend in the mapped area, where the rocks consist almost entirely of graywacke and phyllite, is from near north to N. 20° E. Beds and cleavage of the rocks commonly dip 70° W. or NW. to near vertical. Locally, the rocks are complexly folded or contorted. So major faults were found in the mapped area, but small faults, shear zones, and joints are common. Surficial deposits of the area hare been divided for mapping into the following units: drift deposits, alluvial fan deposits, valley alluvium, intertidal deposits, landslide deposits, and artificial fill. Most of these units intergrade and were deposited more or less contemporaneously. The drift deposits consist chiefly of till that forms moraines along the lower flanks of the Resurrection River valley and up tributary valleys. The till is predominantly silt and sand and lesser amounts of clay-size particles, gravel, cobbles, and boulders. Glacial outwash and stratified ice-contact deposits constitute the remainder of the drift deposits. Fans and fan-deltas have been deposited at the valley mouths of tributary streams. Some, including the one upon which Seward built, project into Resurrection Bay, and deltaic-type deposits form their distal edges. The larger fans—composed chiefly of loosely compacted and poorly sorted silt, sand, and gravel—form broad aprons having low gradients. The fan deposits range in thickness from about 100 feet to possibly several hundred feet and, at least in some places, lie on a platform of compact drift. Smaller fans at the mouths of several canyons have steep gradients and considerable local relief. Valley alluvium, deposited chiefly by the Resurrection River, consists mostly of coarse sand and fine to medium gravel. In the axial part of the valley it is probably more than 100 feet thick. Near the head of Resurrection Bay, the alluvium is underlain by at least 75 feet of marine deltaic sediments, which are in turn underlain by 600 or more feet of drift in the deepest part of the bedrock valley. Beach, deltaic, and estuarine sediments, deposited on intertidal flats at the head of the bay and along far1 margins that extend into the bay, arc mapped as intertidal deposits. They consist mostly of silt, sand, and fine gravel, and lesser amounts of clay-size particles. The earthquake reactivated old slides and trigged new ones in the mountains. Rock and snow avalanches, debris flows, and creep of talus deposits characterized slide activity on the steeper slops. The Seward waterfront had been extended before the earthquake by adding artificial fill consisting of loose sand and gravel; part of the lagoon area had been filled with refuse. After the earth- quake, fill, consisting of silt and sand dredged from the head of the bay, was pumped onto part of the lagoon area and also on land at the northwest corner of the bay. Response to the disaster was immediate and decisive. City, State, and Federal agencies, as well as other organizations and individuals, gave unstintingly of their time and facilities. Within a few days, there was temporary restoration of water, sewerage, and electrical facilities. The U.S. Army Corps of Engineers was authorized to select sites and construct a new dock for the Alaska Railroad, a new small-boat basin, and related facilities. The firm of Shannon and Wilson, Inc., under contract to the Corps of Engineers, investigated subsurface soils extensively to determine the factors responsible for the sliding along the Seward waterfront and to assist in site selection for reconstruction of the destroyed harbor facilities. Borings also made along the Seward waterfront and at the head of the bay, and laboratory tests were conducted on pertinent samples. These studies were augmented by geophysical studies both on land and in the bay. In addition, the Corps of Engineers made shallow borings on the intertidal flats at the head of the bay and performed pile-driving and load tests. Borings also were drilled and test pits were dug in the subdivision of Forest Acres. Sliding along the Seward waterfront markedly deepened the water along the former shoreline. Post-earthquake slopes of the bay floor immediately offshore also are steeper in places than before the earthquake. The strong ground motion of the earthquake triggered the landsliding, but several factors may have contributed to the magnitude and characteristics of the slides. These factors are: (1) the long duration of strong ground motion, (2) the grain size and texture of the material involved in the sliding, (3) the probability that the finer grained materials liquefied and flowed seaward, and (4) the added load of manmade facilities built on the edge of the shore, Secondary effects of the slides themselves—sudden drawdown of water, followed by the weight of returning waves—also may have contributed to the destruction. Submarine sliding at the northwest corner of the bay occurred in fine-grained deltaic deposits whose frontal slopes probably were in metastable equilibrium under static conditions. Uplift pressures from aquifers under hydrostatic head, combined with the probable liquefaction characteristics of the sediments when vibrated by strong ground motion, probably caused the material to slide and flow seaward as a heavy slurry. Under static conditions, no major shoreline or submarine landsliding is expected in the Seward area; in the event of another severe earthquake, however, additional sliding is likely along the Seward waterfront and also in the deltaic deposits at the northwest corner of the bay. Fractured ground in back of the present shoreline along the Seward waterfront is an area of incipient landslides that would be unstable under strong shaking. For this reason the Scientific and Engineering Task Force placed the area in a high-risk classification and recommended no repair, rehabilitation, or new construction in this area involving use of Federal funds; it was further recommended that the area should be reserved for park or other uses that do not involve large congregations of people. The deltaic deposits at the head of the bay probably also would be susceptible to sliding during another large earthquake. This sliding would result in further landward retreat of the present shoreline toward the new railroad dock. Specifications for the new dock, whose seaward end is now approximately 1,100 feet from the back scarp of the subaqueous landslide, require design pro- visions to withstand seismic shock up to certain limits. Earthquake-induced fracturing of the ground in the subdivision of Forest Acres was confined to the lower part of a broad alluvial fan. There, sewer and water lines were ruptured and the foundations of some homes were heavily damaged. Landsliding, such as occurred along the shoreline of the bay, was not a contributing cause of the fracturing. Two hypotheses are offered to explain the fracturing: 1. Seismic energy was transformed into visible surface waves of such amplitude that the strength of surface layer was exceeded and rupturing occurred; tensional and compressional stresses alternately opened and closed the fractures and forced out water and mud. 2. Compaction by vibration of the fine-grained deposits of the fan caused ground settlement and fracturing; ground water under temporary hydrostatic head was forced to the surface as fountains and carried the finer material with it. Water waves that crashed onto shore, while shaking was still continuing, were generated chiefly by onshore and offshore landsliding. Waves that overran the shores about 25 minutes after shaking stopped and that continued to arrive for the next several hours are believed to be seismic sea waves (tsunamis) that originated in an uplifted area in the Gulf of Alaska. During the time of seismic sea-wave activity and perhaps preceding it, seiche wares also may have been generated within Resurrection Bay and complicated the wave effects along the shoreline.

Alaska↗
USGS2013

Bedrock topography of western Cape Cod, Massachusetts, based on bedrock altitudes from geologic borings and analysis of ambient seismic noise by the horizontal-to-vertical spectral-ratio method

This report presents a topographic map of the bedrock surface beneath western Cape Cod, Massachusetts, that was prepared for use in groundwater-flow models of the Sagamore lens of the Cape Cod aquifer. The bedrock surface of western Cape Cod had been characterized previously through seismic refraction surveys and borings drilled to bedrock. The borings were mostly on and near the Massachusetts Military Reservation (MMR). The bedrock surface was first mapped by Oldale (1969), and mapping was updated in 2006 by the Air Force Center for Environmental Excellence (AFCEE, 2006). This report updates the bedrock-surface map with new data points collected by using a passive seismic technique based on the horizontal-to-vertical spectral ratio (HVSR) of ambient seismic noise (Lane and others, 2008) and from borings drilled to bedrock since the 2006 map was prepared. The HVSR method is based on a relationship between the resonance frequency of ambient seismic noise as measured at land surface and the thickness of the unconsolidated sediments that overlie consolidated bedrock. The HVSR method was shown by Lane and others (2008) to be an effective method for determining sediment thickness on Cape Cod owing to the distinct difference in the acoustic impedance between the sediments and the underlying bedrock. The HVSR data for 164 sites were combined with data from 559 borings to bedrock in the study area to create a spatially distributed dataset that was manually contoured to prepare a topographic map of the bedrock surface. The interpreted bedrock surface generally slopes downward to the southeast as was shown on the earlier maps by Oldale (1969) and AFCEE (2006). The surface also has complex small-scale topography characteristic of a glacially eroded surface. More information about the methods used to prepare the map is given in the pamphlet that accompanies this plate.

Massachusetts↗
USGS2015

Hydrogeologic framework, hydrology, and refined conceptual model of groundwater flow for Coastal Plain aquifers at the Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2005-12

From 1966 to 2002, activities at the Standard Chlorine of Delaware chemical facility in New Castle County, Delaware resulted in the contamination of groundwater, soils, and wetland sediment. In 2005, the U.S. Geological Survey (USGS), in partnership with the U.S. Environmental Protection Agency, Region 3, and the Delaware Department of Natural Resources and Environmental Control began a multi-year investigation of the hydrogeologic framework and hydrology of the confined aquifer system. The goals of the ongoing study at the site (the Potomac Aquifer Study) are to determine the hydraulic connection between the Columbia and Potomac aquifers, determine the direction of groundwater flow in the Potomac aquifer, and identify factors affecting the fate of contaminated groundwater. This report describes progress made towards these goals based on available data collected through September 2012. The regional hydrogeologic framework indicates that the site is underlain by Coastal Plain sediments of the Columbia, Merchantville, and Potomac Formations. Two primary aquifers underlying the site, the Columbia and the upper Potomac, are separated by the Merchantville Formation confining unit. Local groundwater flow in the surficial (Columbia) aquifer is controlled by topography and generally flows northward and discharges to nearby surface water. Regional flow within the Potomac aquifer is towards the southeast, and is strongly influenced by major water withdrawals locally. Previous investigations at the site indicated that contaminants, primarily benzene and chlorinated benzene compounds, were present in the Columbia aquifer in most locations; however, there were only limited detections in the upper Potomac aquifer as of 2004. From 2005 through 2012, the USGS designed a monitoring network, assisted with exploratory drilling, collected data at monitoring wells, conducted geophysical surveys, evaluated water-level responses in wells during pumping of a production well, and evaluated major aquifer withdrawals. Data collected through these efforts were used to refine the local conceptual flow system. The refined conceptual flow system for the site includes: (a) identification of gaps in confining units in the study area, (b) identification and correlation of multiple water-bearing sand intervals within the upper Potomac Formation, (c) connections between groundwater and surface water, (d) connections between shallow and deeper groundwater, (e) new water-level (or potentiometric surface) maps and inferred flow directions, and (f) identification of major local pumping well influences. The implications of the revised conceptual flow system on the occurrence and movement of site contaminants are that the resulting detection of contaminants in the upper Potomac aquifer at specific well locations can be attributed primarily to either advective lateral transport, direct vertical contaminant transport, or a combination of vertical and lateral movement resulting from changes in water withdrawal rates over time.

Delaware↗
USGS2022

Potential effects of energy development on environmental resources of the Williston Basin in Montana, North Dakota, and South Dakota—Executive summary

Executive Summary The Williston Basin, which includes parts of Montana, North Dakota, and South Dakota in the United States and parts of Manitoba and Saskatchewan in Canada, has been explored as a potential source of energy resources since the early 20th century; however, commercially viable petroleum drilling and recovery began in earnest in the 1950s. When oil prices rose in the mid-1980s, the number of wells also increased and then subsequently declined. Interest in the Williston Basin increased again in the mid-2000s with the application of new drilling technology. Since then, development has increased rather quickly. Most of this new development has been facilitated by advances in horizontal drilling and hydraulic fracturing technologies. The North Dakota Department of Mineral Resources reported an increase of more than 10,000 producing wells between 2000 and the spring of 2016. In total, 84 percent of those 10,000 wells target the Bakken Formation, which is now home to one of the Nation’s largest energy booms. Current estimates suggest that exploration and drilling activities are expected to continue for the next 20 to 50 years; however, future activity will likely ebb and flow in response to energy prices. Although most energy has been developed on non-Federal property, more than 2,000 wells were started on federally managed lands in the three States that contain the Williston Basin between 2004 and 2015, though these numbers do not reflect whether or not these wells targeted the Bakken Formation. Executive Order no. 13604 (March 22, 2012) directs Federal agencies to improve the timeliness of the permitting process for extracting publically owned minerals, while minimizing negative environmental effects. This means that Federal agencies need information about how energy development may affect other resources they are tasked with managing. One example of where information about potential effects of development may be useful is the Bureau of Land Management’s permitting process. Permits may include stipulations or special conditions that limit unforeseen negative consequences or ameliorate potential conflicts of future development. Federal agencies also need to coordinate permitting actions to ensure that development complies with existing regulations (for example, the Endangered Species Act [16 U.S.C. § 1531 et seq.] or the National Environmental Protection Act [42 U.S.C. § 4321 et seq.]) without unnecessarily restricting or delaying development. Part of this coordination entails agreeing on the information that will be used to assess the potential effects of energy development, which should also improve efficiency of the permitting process. Within the Williston Basin, a group of Federal agencies called the Bakken Federal Executive Group is developing coordination strategies for numerous energy-related issues on Federal lands. This report was developed in cooperation with the Bureau of Land Management to provide them with the best available scientific information to support documentation of potential effects on resources that Federal agencies manage. This report summarizes information about the effects of energy development on air, water, and biological resources within the U.S. part of the Williston Basin. The topics discussed in the report were based on a prioritized list of information needs elicited from the Bakken Federal Executive Group. The list was developed using a process known as structured decision making or decision analysis. This process began with an initial scoping workshop to determine the range of decisions made by those involved directly in managing energy development and resources on public land. U.S. Geological Survey staff then developed a simple quantitative ranking tool to assess which information needs were of greatest importance to those decisions.

Montana, North Dakota, South Dakota↗
USGS2008

Analysis of Streamflow Trends, Ground-Water and Surface-Water Interactions, and Water Quality in the Upper Carson River Basin, Nevada and California

Changes in land and water use and increasing development of water resources in the Carson River basin may affect flow of the river and, in turn, affect downstream water users dependent on sustained river flows to Lahontan Reservoir. To address these concerns, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, Churchill County, and the Truckee-Carson Irrigation District, began a study in April 2006 to compile data on changes in land and water use, ground-water levels and pumping, streamflow, and water quality, and to make preliminary analyses of ground-water and surface-water interactions in the Carson River basin upstream of Lahontan Reservoir. The part of the basin upstream of Lahontan Reservoir is called the upper Carson River basin in this report. In 2005, irrigated agricultural land covered about 39,000 acres in Carson Valley, 3,100 acres in Dayton Valley, and 1,200 acres in Churchill Valley. Changes in land use in Carson Valley from the 1970s to 2005 included the development of about 2,700 acres of native phreatophytes, the development of 2,200 acres of irrigated land, 900 acres of land irrigated in the 1970s that appeared fallow in 2005, and the irrigation of about 2,100 acres of new agricultural land. In Dayton and Churchill Valleys, about 1,000 acres of phreatophytes and 900 acres of irrigated land were developed, about 140 acres of phreatophytes were replaced by irrigation, and about 600 acres of land irrigated in the 1970s were not irrigated in 2006. Ground-water pumping in the upper Carson River basin increases during dry years to supplement surface-water irrigation. Total annual pumping exceeded 20,000 acre-ft in the dry year of 1976, exceeded 30,000 acre-ft in the dry years from 1987 to 1992, and increased rapidly during the dry years from 1999 to 2004, and exceeded 50,000 acre-ft in 2004. As many as 67 public supply wells and 46 irrigation wells have been drilled within 0.5 mile of the Carson River. Pumping from these wells has the potential to affect streamflow of the Carson River. It is not certain, however, if all these wells are used currently. Annual streamflow of the Carson River is extremely variable, ranging from a low of about 26,000 acre-ft in 1977 to slightly more than 800,000 acre-ft in 1983 near Fort Churchill. Graphs of the cumulative annual streamflow and differences in the cumulative annual streamflow at Carson River gaging stations upstream and downstream of Carson and Dayton Valleys show an annual decrease in streamflow. The annual decrease in Carson River streamflow averaged about 47,000 acre-ft through Carson Valley, and about 11,000 acre-ft through Dayton Valley for water years 1940-2006. The decrease in streamflow through Carson and Dayton Valleys is a result of evapotranspiration on irrigated lands and losses to ground-water storage, with greater losses in Carson Valley than in Dayton Valley because of the greater area of irrigated land in Carson Valley.

Scientific Investigations Report↗
USGS2015

Hydrogeology, groundwater levels, and generalized potentiometric-surface map of the Green River Basin lower Tertiary aquifer system, 2010–14, in the northern Green River structural basin

In cooperation with the Bureau of Land Management, groundwater levels in wells located in the northern Green River Basin in Wyoming, an area of ongoing energy development, were measured by the U.S. Geological Survey from 2010 to 2014. The wells were completed in the uppermost aquifers of the Green River Basin lower Tertiary aquifer system, which is a complex regional aquifer system that provides water to most wells in the area. Except for near perennial streams, groundwater-level altitudes in most aquifers generally decreased with increasing depth, indicating a general downward potential for groundwater movement in the study area. Drilled depth of the wells was observed as a useful indicator of depth to groundwater such that deeper wells typically had a greater depth to groundwater. Comparison of a subset of wells included in this study that had historical groundwater levels that were measured during the 1960s and 1970s and again between 2012 and 2014 indicated that, overall, most of the wells showed a net decline in groundwater levels. The groundwater-level measurements were used to construct a generalized potentiometric-surface map of the Green River Basin lower Tertiary aquifer system. Groundwater-level altitudes measured in nonflowing and flowing wells used to construct the potentiometric-surface map ranged from 6,451 to 7,307 feet (excluding four unmeasured flowing wells used for contour construction purposes). The potentiometric-surface map indicates that groundwater in the study area generally moves from north to south, but this pattern of flow is altered locally by groundwater divides, groundwater discharge to the Green River, and possibly to a tributary river (Big Sandy River) and two reservoirs (Fontenelle and Big Sandy Reservoirs).

Wyoming↗
USGS2019

Drinking water health standards comparison and chemical analysis of groundwater for 72 domestic wells in Bradford County, Pennsylvania, 2016

Pennsylvania has the second highest number of residential wells of any state in the Nation with approximately 2.4 million residents that depend on groundwater for their domestic water supply. Despite the widespread reliance on groundwater in rural areas of the state, publicly available data to characterize the quality of private well water are limited. In Bradford County, more than half of the residents use groundwater from private domestic-supply wells as their primary drinking source. The quality of private well water is influenced by the regional and local setting, including the surrounding soil, geology, land use, household plumbing, and well construction. The groundwater used for domestic water supply in Bradford County is obtained primarily from shallow bedrock and from unconsolidated (glacial) deposits that overlie the bedrock. Historical land use has been predominately forested, agricultural, and residential, but more recently unconventional oil/gas development has been distributed throughout the landscape. Pennsylvania is one of only two states in the Nation without statewide water-well construction standards. To better assess the quality of groundwater used for drinking water supply in Bradford County, data for 72 domestic wells were collected and analyzed for a wide range of constituents that could be evaluated in relation to drinking water health standards, geology, land use, and other environmental factors. Groundwater samples were collected from May through August 2016 and analyzed for physical and chemical properties, including major ions, nutrients, trace elements, volatile organic compounds, ethylene and propylene glycol, alcohols, gross-alpha/beta-particle activity, uranium, radon-222, and dissolved gases. A subset of samples was analyzed for radium isotopes (radium-226 and -228) and for the isotopic composition of methane. This study was conducted by the U.S. Geological Survey in cooperation with the Northern Tier Regional Planning and Development Commission and is part of a regional effort to characterize groundwater in rural areas of Pennsylvania. Results of the 2016 study show that groundwater quality generally met most drinking-water standards. However, a percentage of samples failed to meet maximum contaminant levels (MCLs) for total coliform bacteria (49.3 percent), Escherichia coli (8.5 percent), barium (2.8 percent), and arsenic (2.8 percent); and secondary maximum contaminant levels (SMCL) for sodium (48.6 percent), manganese (30.6 percent), gross alpha and beta activity (16.7 percent), iron (11.1 percent), pH (8.3 percent), total dissolved solids (5.6 percent), chloride (1.4 percent), and aluminum (1.4 percent). Radon-222 activities exceeded the proposed drinking-water standard of 300 picocuries per liter (pCi/L) in 70.4 percent of the samples. There were no exceedances of drinking water health standards for any volatile organic compounds, and the only detections were for three trihalomethanes in one sample. The pH of the groundwater had a large influence on chemical characteristics and ranged from 6.18 to 9.31. Generally, the higher pH samples had higher potential for elevated concentrations of several constituents, including total dissolved solids, sodium, lithium, chloride, fluoride, boron, arsenic, and methane. For the Bradford County well-water samples, calcium/bicarbonate type waters were most abundant, with others classified as sodium/bicarbonate or mixed water types including calcium-sodium/bicarbonate, calcium-sodium/bicarbonate-chloride, sodium/bicarbonate-chloride, sodium/bicarbonate-sulfate, or sodium/chloride types. Six principal components (pH, redox, hardness, chloride-bromide, strontium-barium, and molybdenum-arsenic) explained nearly 78.3 percent of the variance in the groundwater dataset. Groundwater from 12.5 percent of the wells had concentrations of methane greater than the Pennsylvania action level of 7 milligrams per liter (mg/L); detectable methane concentrations ranged from 0.01 to 77 mg/L. In addition, low levels of ethane (as much as 0.13 mg/L) were present in seven samples with the highest methane concentrations. The isotopic composition of methane in five of these groundwater samples was consistent with the isotopic compositions reported for mud-gas logging samples from these geologic units and a thermogenic source. Isotopic composition from a sixth sample suggested the methane in that sample may be of microbial origin. Well-water samples with the higher methane concentrations also had higher pH values and elevated concentrations of sodium, lithium, boron, fluoride, arsenic, and bromide. Relatively elevated concentrations of some other constituents, such as barium and chloride, commonly were present in, but not limited to, those well-water samples with elevated methane. Four of the six groundwater samples with the highest methane concentrations had chloride/bromide ratios that indicate mixing with a small amount of brine (0.02 percent or less) similar in composition to those reported for gas and oil well brines in Pennsylvania. In several other eastern Pennsylvania counties where gas drilling is absent, groundwater with comparable chloride/bromide ratios and chloride concentrations have been reported, implying a potential natural source of brine. Most of Bradford County well-water samples have chloride concentrations less than 20 mg/L, and those with higher chloride concentrations have chloride/bromide ratios that indicate anthropogenic sources (such as road-deicing salt and septic effluent) or brine. Brines that are naturally present may originate from deeper parts of the aquifer system, whereas anthropogenic sources are more likely to affect shallow groundwater because they occur on or near the land surface. The available data for this study indicate that no one physical factor, such as the topographic setting, well depth, or altitude at the bottom of the well, was particularly useful for predicting those well locations with an elevated dissolved concentration of methane. The 2016 assessment of groundwater quality in Bradford County shows groundwater is generally of good quality, but methane and some constituents that occur in high concentration in naturally occurring brine and also in produced waters may be present at low to moderate concentrations in groundwater in various parts of the aquifer.

Pennsylvania↗
USGS2019

Lithologic descriptions, geophysical logs, and source-rock geochemistry of the U.S. Geological Survey Alcova Reservoir AR–1–13 Core Hole, Natrona County, Wyoming

In 2013, a continuous 624-foot core hole was drilled and logged by the U.S. Geological Survey in Natrona County, Wyoming, with the goal to better understand Cretaceous source rocks in the Wind River Basin. The core hole, named the Alcova Reservoir AR–1–13, penetrated the interval extending from the upper part of the Lower Cretaceous Cloverly Formation to the lower part of the Upper Cretaceous Frontier Formation. The lithologies are predominantly mudrock, with minor amounts of sandstone and altered volcanic ash beds that were deposited in open marine, nearshore marine, and fluvial settings. Samples were collected from open marine clay-rich, dark-colored mudrocks, and these were analyzed for total organic carbon content and by programmed pyrolysis analysis. The results show that the lower part of the Frontier Formation, Shell Creek Shale equivalent, and the Thermopolis Shale contain Type III gas-prone kerogen, with poor to fair generative source rock potential. The upper part of the Mowry Shale has good to excellent generative potential, with organic matter composed mainly of Type II oil-prone kerogen with some mixed Type II/III kerogen capable of generating oil and gas.

Wyoming↗
USGS2012

Aquifer test at well SMW-1 near Moenkopi, Arizona

The Hopi villages of Lower Moencopi and Upper Moenkopi are on the Hopi Indian Reservation south of Tuba City in northern Arizona. These adjacent Hopi villages, located west and north of the confluence of Pasture Canyon Wash and Moenkopi Wash, are dependent on groundwater withdrawals from three wells that penetrate the N aquifer and from two springs that discharge from the N aquifer. The N aquifer is the principal aquifer in this region of northern Arizona and is composed of thick beds of sandstone between less permeable layers of siltstone and mudstone. The fine-grained character of the N aquifer inhibits rapid movement of water and large yields to wells; however, the aquifer is moderately productive at yields generally less than 25 gallons per minute in the study area. In recent years, the water level has declined in the three public-supply wells and the flow from the springs has decreased, causing concern that the current water supply will not be able to accommodate peak demand and allow for residential and economic growth. In addition to the challenge imposed by declining groundwater levels, the water-supply wells and springs are located about 2 miles downgradient from the Tuba City Landfill site where studies are ongoing to determine if uranium and other metals in groundwater beneath the landfill are higher than regional concentrations in the N aquifer. In August 2008, the U.S. Geological Survey, in cooperation with the Hopi Tribe, conducted an aquifer test on well SMW-1, designed to help the Hopi Tribe determine the potential yield and water quality of the N aquifer south of Moenkopi Wash as a possible source of additional water supply. Well SMW-1 was drilled south of Moenkopi Wash to a depth of 760 feet below land surface before being backfilled and cased to about 300 feet. The well penetrates, in descending order, the Navajo Sandstone and the Kayenta Formation, both units of the N aquifer. The pre-test water level in the well was 99.15 feet below land surface. A 9.25-hour step-drawdown test and a 72-hour constant-rate test followed by recovery tests were used to investigate the performance of the test well and to estimate the transmissivity and potential yield of the N aquifer south of Moenkopi Wash. The test data were analyzed using the Cooper-Jacob method adjusted for confined conditions, the Papadopulos-Cooper method that accounts for wellbore storage, and the Theis method on the recovery data. Results of the tests indicate that in the vicinity of the well, the N aquifer has a transmissivity of about 50 feet squared per day. The test well, as completed, should yield about 15 gallons per minute with about 75 feet of drawdown (less than half of the available saturated thickness of the aquifer at the well).

Arizona↗
USGS1963

Preliminary report on the geology and hydrology of Mortandad Canyon near Los Alamos, New Mexico, with reference to disposal of liquid low-level radioactive waste

The U.S. Geological Survey, in cooperation with the U.S. Atomic Energy Commission and the Los Alamos Scientific Laboratory, selected the upper part of Mortandad Canyon near Los Alamos, New Mexico for a site for disposal of treated liquid low-level radioactive waste. This report summarizes the part of a study of the geology and hydrology that was done from October 1960 through June 1961. Additional work is being continued. Mortandad Canyon is a narrow east-southeast-trending canyon about 9? miles long that heads on the central part of the Pajarito Plateau at an altitude of about 7,340 feet. The canyon is tributary to the Rio Grande. The drainage area of the part of Mortandad Canyon that was investigated is about 2 square miles, and the total drainage area is about 4.9 square miles. The Pajarito Plateau is capped by the Bandelier Tuff of Pleistocene age. Mortandad Canyon is cut in the Bandelier, and alluvium covers the floor of the canyon to depths ranging from less than 1 foot to as much as 100 feet. The Bandelier is underlain by silt, sand, conglomerate, and interbedded basalt of the Santa Fe Group of Miocene, Pliocene, and Pleistocene(?) age. Some ground water is perched in the alluvium in the canyon; however, the top of the main aquifer is in the Santa Fe Group at a depth of about 990 feet below the canyon floor. Joints in the Bandelier Tuff probably were caused by shrinkage of the tuff during cooling. The joints range in width from hairline cracks to fissures several inches wide. Water can infiltrate along the open joints where the Bandelier is at the surface; however, soil, alluvial fill, and autochthonous clay inhibit infiltration on the tops of mesas and probably in the alluvium-floored canyons also. Thirty-three test holes, each less than 100 feet deep, were drilled in 10 lies across Mortandad Canyon from the western margin of the study area to just west of the Los Alamos-Santa Fe County line. Ten of the holes were cased for observation wells to measure water levels and collect water samples from the alluvium. Twenty-three of the holes were cased to seal out water and were used as access tubes to accommodate a neutron-neutron probe for determining the moisture content of the alluvium and tuff. The source of recharge for the perched ground-water body in the alluvium in Mortandad Canyon is the precipitation in the drainage area of the canyon. During the winter of 1960-61, a snowpack 1-2 feet thick accumulated in the narrow shaded upper part of the canyon. The alluvium below the snowpack received some recharge because of diurnal melting during the winter. In March 1961 the snowmelt water saturated most of the thin alluvium in the upper part of the canyon, and a surface stream began to flow on the alluvium. The maximum flow of the stream was about 250 gpm (gallons per minute). Water from the stream infiltrated the alluvium at the front of the stream and in the reach upstream from the front. A ground-water mound was formed beneath the channel by water infiltrating from the stream. The front of the stream and the front of the ground-water mound advanced eastward to about the middle of the area studied. From this point eastward, the alluvium was thick enough to absorb and transmit the amount of flow in 1961. Late in April the front of the stream retreated, and by the first of May the flow stopped. During and after this period the ground-water mound decayed, and ground-water levels declined in the upper part of the canyon as water drained into the channel and downgradient through the alluvium. The amount of recharge was small in the wide lower part of the canyon during the period of study. The rise in ground-water levels and the increase in moisture content of the alluvium in the lower part of the canyon indicate that water moved downgradient by underflow through the alluvium from the recharge area in the upper part of the canyon. Moisture measurements indicate that only a little water moved into the underlyin

Open-File Report↗
USGS2015

California State Waters Map Series: Offshore of Refugio Beach, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Refugio Beach map lies within the western Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges province, and geodetic studies indicate that the region is presently undergoing north-south shortening. Uplift rates (as much as 0.5 mm/yr) that are based on studies of onland marine terraces provide further evidence of significant shortening. The coastal zone of this map area lies at the steep flank of the Santa Ynez Mountains. The crest of the range, which lies about 8 km from the shoreline (north of the map area), has a maximum elevation of about 780 m. This area is largely open space, partly used for livestock grazing, with no significant towns or population centers. Highway 101 crosses the map area, adjacent to and within a few hundred meters of the shoreline. The most significant developments are the recreational state beaches at El Capitan Beach and Refugio Beach. The beaches are subject to erosion each winter during storm-wave attack, and then they undergo gradual recovery or accretion during the more gentle wave climate of the late spring, summer, and fall months. The Offshore of Refugio Beach map area lies in the west-central part of the Santa Barbara littoral cell, which is characterized by west-to-east transport of sediment from Point Arguello on the northwest to Hueneme and Mugu Canyons on the southeast. Longshore drift rates have been reported to range from about 160,000 to 800,000 tons/yr, averaging 400,000 tons/yr. Sediment supply to the western and central part of the littoral cell, including the map area, is mainly from relatively small coastal watersheds. Within the map area, these coastal watersheds include (from east to west) Cañada del Capitan, Tajiquas Creek, Arroyo Hondo, Cañada del Molino, and several unnamed canyons and creeks. The Santa Ynez and Santa Maria Rivers, the mouths of which are 80 to 120 km northwest of the map area, are not considered significant sediment sources because Point Conception and Point Arguello provide obstacles to downcoast sediment transport and also because much of their sediment load is trapped in dams. The Ventura and Santa Clara Rivers, the mouths of which are about 70 km to the southeast of the map area, are not sediment sources for the map area. The offshore part of the map area consists of relatively flat and shallow continental shelf, which dips gently seaward (about 0.8° to 1.0°) so that water depths at the shelf break, roughly coincident with the California’s State Waters limit, are about 80 to 100 m. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north and northwest by Point Conception and from the south and southwest by offshore islands and banks. The shelf is underlain by variable amounts of upper Quaternary marine and fluvial sediments deposited as sea level fluctuated in the late Pleistocene. In the map area, the shelf break is at depths of about 90 m and lies about 5.6 to 6.4 km offshore. Beyond the shelf break, the slope is steep (as much as about 7°) and unstable. Several submarine landslides, including the large (130 km 2 ) Goleta landslide complex, have been documented offshore of Goleta, a few kilometers east of the map area. This compound slump complex may have been initiated more than 200,000 year ago, but it also includes three recent failures that may have been generated 8,000 to 10,000 years ago. A local, 10-m-high tsunami may have been generated from these failure events. Small folds related to local faulting are superimposed on the homocline that makes up the south flank of the Santa Ynez Mountains. One of these superimposed anticlines hosts the Molino gas field, which was discovered in 1962 and subsequently developed through directional drilling from onshore wells. The Oligocene Sespe and Vaqueros Formations are the reservoirs in the Molino gas field, and the map area includes numerous seafloor hydrocarbon seeps. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft, unconsolidated sediment interspersed with isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Offshore of Refugio Beach map area are directly related to its Quaternary geologic history, geomorphology, and active sedimentary processes. These potential habitats, which lie primarily within the Shelf (continental shelf) but also partly within the Flank (basin flank or continental slope) megahabitats, primarily are composed of soft sediment interrupted by a few carbonate mounds. This homogeneous seafloor of sediment and low-relief bedrock provides promising habitat for groundfish, crabs, shrimp, and other marine benthic organisms.

California↗
USGS2005

Surface gamma-ray survey of the Barre West quadrangle, Washington and Orange Counties, Vermont

This study was designed to determine the levels of naturally occurring radioactivity in bedrock from surface measurements at outcrops during the course of 1:24,000-scale geologic mapping and to determine which rock types were potential sources of radionuclides. Elevated levels of total alpha particle radiation (gross alpha) occur in a public water system in Montpelier, Vermont. Measured gross alpha levels in the Murray Hill water system (Vermont Dept. of Environmental Conservation, unpub. data, 2005) have exceeded the maximum contaminant level of 15 picocuries per liter (pCi/l) set by the Environmental Protection Agency (EPA) (EPA, 2000). The Murray Hill system began treatment for radium in 1999. Although this treatment was successful, annual monitoring for gross alpha, radium, and uranium continues as required (Jon Kim, written communication, 2005). The water system utilizes a drilled bedrock well located in the Silurian-Devonian Waits River Formation. Kim (2002) summarized radioactivity data for Vermont, and aside from a statewide assessment of radon in public water systems (Manning and Ladue, 1986) and a single flight line from the National Uranium Resource Evaluation (NURE) (Texas Instruments, 1976) (fig. 1), no data are available to identify the potential sources of naturally occurring radioactivity in the local bedrock. Airborne gamma-ray surveys are typically used for large areas (Duval, 2001, 2002), and ground-based surveys are more commonly used for local site assessments. For example, ground-based surveys have been used for fault mapping (Iwata and others, 2001), soil mapping (Roberts and others, 2003), environmental assessments (Stromswold and Arthur, 1996), and mineral exploration (Jubeli and others, 1998). Duval (1980) summarized the methods and applications of gamma- ray spectrometry. In this study, we present the results from a ground-based gamma-ray survey of bedrock outcrops in the 7.5-minute Barre West quadrangle, Vermont. Other related and ongoing studies in the area are addressing potential mineral sources of radionuclides (Satkoski and Walsh, 2004; Satkoski and others, 2005), radionuclides in ground water (Kim and others, 2005), and bedrock geology.

Scientific Investigations Report↗
USGS2026

Regional characterization of coal resources in the Gulf Coast Coal Region—In support of coal as a potential source for critical minerals and rare earth elements

There is increasing interest in extracting critical minerals (CM), including rare earth elements (REE), from coals in the United States to address the overreliance on imported REE. The Gulf Coast and the Fort Union regions are the two major lignite-bearing regions within the United States. Recent REE and CM studies of the lignite in these regions have indicated that the coals may be a viable source material for REE and CM extraction. To evaluate in-place coal as a potential source of REE and CM, the coal resources need to be quantified. This study presents the results of a regional analysis of Gulf Coast Coal Region lignite and bituminous coal resources that might be available as potential sources of REE and CM. The resource analysis used kriging methods to develop isopleth maps of cumulative coal thickness throughout the region using data from drill holes and measured mine and outcrop sections for a total of 31,181 data points. The estimated total remaining coal resource in the Gulf Coast Coal Region is about 83 billion metric tons in the upper 90 meters (approximately 300 feet) of the subsurface. The current estimate of remaining coal resources includes approximately 1.88 billion metric tons of coal that have been extracted in the region since 1983. Texas accounted for 39 percent (32 billion metric tons) of the remaining total resource, followed by Mississippi (24 percent, 20 billion metric tons ), Louisiana (14 percent, 12 billion metric tons), Tennessee (10 percent, 8.5 billion metric tons), and Arkansas (6 percent, 5.1 billion metric tons). Alabama, Georgia, Kentucky, and Missouri each accounted for less than 5 percent of the total resource; Georgia had the smallest resource estimated at 7 million metric tons. Here we report the first known statewide lignite resource estimates for Georgia, Kentucky (820 million metric tons), and Missouri (1,800 million metric tons). A comparison of the results of this study with those of previous Gulf Coast Coal Region and Fort Union Coal Region resource studies is difficult because each study used different data sources, assessment methodologies, overburden depths, and qualifying coal thicknesses.

Alabama, Arkansas, Florida, Georgia, Illinois, Lou↗
USGS2017

The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States

This report describes the discovery and geology of two near-surface uranium deposits within calcareous lacustrine strata of Pleistocene age in west Texas, United States. Calcrete uranium deposits have not been previously reported in the United States. The west Texas uranium deposits share characteristics with some calcrete uranium deposits in Western Australia—uranium-vanadium minerals hosted by nonpedogenic calcretes deposited in saline lacustrine environments. In the mid-1970s, Kerr-McGee Corporation conducted a regional uranium exploration program in the Southern High Plains province of the United States, which led to the discovery of two shallow uranium deposits (that were not publicly reported). With extensive drilling, Kerr-McGee delineated one deposit of about 2.1 million metric tons of ore with an average grade of 0.037 percent U 3 O 8 and another deposit of about 0.93 million metric tons of ore averaging 0.047 percent U 3 O 8 . The west-Texas calcrete uranium-vanadium deposits occur in calcareous, fine-grained sediments interpreted to be deposited in saline lakes formed during dry interglacial periods of the Pleistocene. The lakes were associated with drainages upstream of a large Pleistocene lake. Age determinations of tephra in strata adjacent to one deposit indicate the host strata is middle Pleistocene in age. Examination of the uranium-vanadium mineralization by scanning-electron microscopy indicated at least two generations of uranium-vanadium deposition in the lacustrine strata identified as carnotite and a strontium-uranium-vanadium mineral. Preliminary uranium-series results indicate a two-component system in the host calcrete, with early lacustrine carbonate that was deposited (or recrystallized) about 190 kilo-annum, followed much later by carnotite-rich crusts and strontium-uranium-vanadium mineralization in the Holocene (about 5 kilo-annum). Differences in initial 234 U/ 238 U activity ratios indicate two separate, distinct fluid sources.

Texas↗
USGS2015

Feasibility and potential effects of the proposed Amargosa Creek Recharge Project, Palmdale, California

Historically, the city of Palmdale and vicinity have relied on groundwater as the primary source of water, owing, in large part, to the scarcity of surface water in the region. Despite recent importing of surface water, groundwater withdrawal for municipal, industrial, and agricultural use has resulted in groundwater-level declines near the city of Palmdale in excess of 200 feet since the early 1900s. To meet the growing water demand in the area, the city of Palmdale has proposed the Amargosa Creek Recharge Project (ACRP), which has a footprint of about 150 acres along the Amargosa Creek 2 miles west of Palmdale, California. The objective of this study was to evaluate the long-term feasibility of recharging the Antelope Valley aquifer system by using infiltration of imported surface water from the California State Water Project in percolation basins at the ACRP. Three monitoring sites were constructed, and geophysical surveys (gravity, seismic, and resistivity) were completed to define the thickness of valley-fill deposits, depth to water, and location of faults that could influence groundwater flow. Data collected at the monitoring sites, and results from the geophysical surveys, were used to identify three northwest-southeast trending faults in the vicinity of the proposed recharge facility; these faults are probably related to the nearby San Andreas fault zone. Water levels collected from wells at the monitoring sites showed water-level altitude differences as much as 230 feet between the upgradient and downgradient sides of the faults, indicating that these faults are barriers to groundwater flow. Lithologic and geophysical logs indicated the presence of a coarse gravel and sand unit extending from land surface to about 150 feet below land surface that did not appear to be disrupted by faulting. Water samples collected from the monitoring wells were analyzed for major ions, nutrients, trace elements, dissolved organic carbon, volatile organic compounds, stable isotopes of oxygen (oxygen-18) and hydrogen (hydrogen-2, or deuterium), and the radioactive isotopes of hydrogen (hydrogen-3, or tritium) and carbon (carbon-14, or 14 C) to determine the water quality of the aquifer system and to help determine the source and age of the groundwater. Results of the water-quality analysis indicated that the source of natural recharge is Amargosa Creek near the ACRP, but that the creek does not provide modern-day recharge downstream of the ACRP. Potential effects of artificial recharge at the ACRP were evaluated by using a local-scale model of groundwater flow. On the basis of geologic samples collected during drilling, the hydraulic conductivity of the sand and gravel unit in the upper 150 feet was assumed to range from 10 to 100 feet per day. To address the goal of minimizing the potential for liquefaction during an earthquake from water-table rise associated with groundwater recharge at the ACRP, simulated water levels were constrained to remain at least 50 feet below land surface, except beneath the proposed artificial-recharge facility. The hydraulic conductivities of faults were estimated on the basis of water-level data and an estimate of natural recharge along Amargosa Creek. With assumed horizontal hydraulic conductivities of 10 and 100 feet per day in the upper 150 feet, the simulated maximum artificial recharge rates to the regional flow system at the ACRP were 3,400 and 9,400 acre-feet per year, respectively. These maximum recharge rates were limited primarily by the horizontal hydraulic conductivity in the upper 150 feet and by the liquefaction constraint. Future monitoring of water-level and soil-water content changes during the proposed project would allow improved estimation of aquifer hydraulic properties, the effect of the faults on groundwater movement, and the overall recharge capacity of the ACRP.

California↗
USGS2004

Trends in streamflow and comparisons with instream flows in the lower Puyallup River basin, Washington

The Puyallup Tribe of Indians is interested in better understanding the water resources of the lower Puyallup River Basin in order to ensure sufficient water to meet Tribal and hatchery needs and make future water-resource decisions. The U.S. Geological Survey, in cooperation with the Puyallup Tribe, conducted a study to identify trends in streamflow in the lower Puyallup River Basin and to compare streamflows in the Puyallup River with regulatory minimum instream flows. Daily mean streamflow, monthly mean streamflow for October, and annual mean streamflow records from 1980 through 2001 for two gaging stations on the lower Puyallup River and one each on Clarks Creek and Swan Creek in the lower Puyallup River Basin were analyzed for temporal trends. Daily mean streamflow records were divided into data sets for the wet period (November through June) and the dry period (July through October) for analysis. Annual precipitation records from three National Weather Service stations and ground-water-level records from five wells in the lower Puyallup River Basin were analyzed to determine possible relations with streamflow. Daily mean streamflow, daily minimum streamflow, and unit-streamflow records for the Puyallup River for 1991 and 1992 were evaluated for the instream-flow analysis. Significant temporal trends were not identified in daily mean streamflow records from the Puyallup River, Clarks Creek, or Swan Creek for the period of analysis. Trend analysis of monthly mean streamflow records for October at two gaging stations on the Puyallup River also indicated no significant trends for the period of analysis. Temporal trends were not evident in precipitation data from weather stations in the basin. A trend of decreasing depth to ground water with time (1995 through 1997) was identified in one well (20N/04E-34G01). This well is drilled to about 550 feet below land surface, and variations in water levels at this depth likely do not affect streamflow in the Puyallup River. Data limitations prevented the evaluation of possible correlations between streamflow in the Puyallup River and water use and land use in the study basin. Daily mean, daily minimum, and unit-streamflow values were evaluated to determine how each measure of streamflow compared with instream-flow values. The occurrence of excursions (streamflow below the instream-flow value) was greatest when unit-streamflow values were compared with instream-flow values. The use of daily mean streamflow records may underestimate the occurrence of excursions under certain streamflow conditions. The unit-streamflow hydrograph for the Puyallup River at Puyallup exhibits a distinct, regular pattern. The hydrograph closely mimics the hydrograph at Lake Tapps Diversion, on the White River, a tributary of the Puyallup River, which is the outflow from a power plant, suggesting that the power-plant outflow affects streamflow in the Puyallup River. Streamflow entering Lake Tapps through the White River Canal does not exhibit the same pattern as the Puyallup River or diversion. The influence of the White River Canal on streamflow in the Puyallup River appears to be obscured by operation of the Lake Tapps Diversion.

Washington↗
USGS2007

Effects of saline-wastewater injection on water quality in the Altamont-Bluebell oil and gas field, Duchesne County, Utah, 1990-2005

The Altamont-Bluebell oil and gas field in the Uinta Basin in northeastern Utah has been an important oil and natural gas production area since the 1950s. Saline water is produced along with oil during the oil-well drilling and pumping process. The saline wastewater is disposed of by injection into wells completed in the Duchesne River Formation, Uinta Formation, and other underlying formations. There are concerns that the injected saline wastewater could migrate into the upper part of the Duchesne River and Uinta Formations and surficial deposits that are used for drinking-water supply and degrade the quality of the drinking water. The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Oil, Gas, and Mining, began a program in 1990 to monitor water quality in five wells in the Altamont-Bluebell oil and gas field. By 1996, water-quality samples had been collected from 20 wells. Ten of the 20 wells were sampled yearly during 1996-2005 and analyzed for bromide, chloride, and stable isotopes. Comparison of major chemical constituents, bromide-to-chloride ratios, trend analysis, and isotope ratios were used to assess if saline wastewater is migrating into parts of the formation that are developed for drinking-water supplies. Results of four different analyses all indicate that saline wastewater injected into the lower part of the Duchesne River and Uinta Formations and underlying formations is not migrating upward into the upper parts of the formations that are used for drinking-water supplies.

Utah↗
USGS2004

Direction of ground-water flow in the surficial aquifer in the vicinity of impact areas G-10 and K-2, Camp Lejeune Marine Corps Base, North Carolina, 2004

Marine Corps Base Camp Lejeune is located in Onslow County in the North Carolina Coastal Plain. In support of North Carolina Department of Environment and Natural Resource requirements, Camp Lejeune is developing a site closure plan for two Resource Conservation and Recovery Act (RCRA) regulated open burn/open detonation (OB/OD) facilities located within Impact Area K-2 and Impact Area G-10, respectively. Both Impact Areas are used for training activities involving live artillery fire. The two OB/OD facilities are used to treat RCRA regulated waste munitions. To provide Base officials with information needed for assessing the quality of ground water at these sites, hydrologic data were used to characterize groundwater flow directions and hydraulic gradients in the surficial aquifer underlying the Impact Areas. Water-level data in the unconfined surficial aquifer and potentiometric head data in the underlying Castle Hayne aquifer were compiled from existing and newly drilled wells. Water-table contour maps were developed for Impact Areas K-2 and G-10 to examine the direction of ground-water flow in the surficial aquifer. The primary directions of ground-water flow beneath K-2 are southward and eastward toward discharge zones along the New River and its tributaries. Beneath interior areas of G-10, water in the surficial aquifer flows outward in all directions toward discharge zones along local streams that drain westward to the New River or to streams that drain southward and eastward to the Intracoastal Waterway and the Atlantic Ocean. Long-term water-level data for the period October 1994 through September 2004 at selected Camp Lejeune well sites were used to examine trends in ground-water levels and vertical hydraulic gradients between the surficial and Castle Hayne aquifers. Evaluation of water-level data for three wells in the surficial aquifer indicated no significant trends for this period of record. The apparent water-level declines in two of the three Castle Hayne wells examined are likely the result of local pumping of the Castle Hayne aquifer. Vertical hydraulic gradients determined for two well cluster sites indicate a downward flow of water from the surficial aquifer into the underlying Castle Hayne aquifer.

Scientific Investigations Report↗