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At least 577 records · Page 32Linked to original sources
USGS2006

Effects of tributary debris on the longitudinal profile of the Colorado River in Grand Canyon

The Colorado River in Grand Canyon has long been known as a "rapids-and-pools" river, with the rapids owing their existence primarily to tributary debris flows. The debris flows deposit subaerial debris fans that constrict the channel laterally and, when they enter the river, raise the bed elevation. The rapids are short-wavelength (???0.1 to ???1 km), small-amplitude (??????5 m) convexities in the river's longitudinal profile, arising from the shallow gradient in the upstream pool and the steep gradient through the rapid itself. Analysis of the entire longitudinal profile through Grand Canyon reveals two long-wavelength (???100 km), large-amplitude (15-30 m) river profile convexities: the eastern canyon convexity between river mile (RM) 30 and RM 80 and the western canyon convexity between RM 150 and RM 250. Convexities of intermediate scale are also identified in the longitudinal profile. These longer-wavelength, larger-amplitude convexities have strong spatial correlations with high rates of debris flow occurrence, high densities of Holocene debris fans, the largest debris fans along the river, and alluvial thicknesses of 10 m or more. River profile convexities are unstable and require an active and powerful geologic process to maintain them, in this case the abundant, frequent, and voluminous Holocene debris flow activity in Grand Canyon. At all wavelengths the most likely cause for these river profile convexities is Holocene aggradation of the riverbed beneath them, driven by the coarse particles of tributary debris flows. Large enough debris flows will slow river flow for kilometers upstream, causing it to drop much of its suspended load. Integrated over time and all of the tributary point source contributions, this process will build short-wavelength convexities into long-wavelength convexities. For most if not all of the Holocene the Colorado River has been dissipating most of its energy in the rapids and expending the remainder in transporting fine sediment through Grand Canyon, with little or no regional incision of bedrock.

Journal of Geophysical Research F: Earth Surface↗
USGS2019

Airborne radiometric maps of Mountain Pass, California

Geophysical investigations of Mountain Pass and vicinity were begun as part of an effort to study regional crustal structures as an aid to understanding the geologic framework and mineral resources of the eastern Mojave Desert. The study area encompasses Mountain Pass, host to one of the world’s largest rare earth element carbonatite deposits. The deposit is found along a north-northwest-trending, fault-bounded block that extends along the eastern parts of the Clark Mountain Range, Mescal Range, and Ivanpah Mountains. This Paleoproterozoic block is composed of a 1.7-Ga metamorphic complex of gneiss and schist that underwent widespread metamorphism and associated plutonism during the Ivanpah orogeny. The Paleoproterozoic rocks were intruded by a Mesoproterozoic (1.4 Ga) ultrapotassic alkaline intrusive suite and carbonatite body. The intrusive rocks include, from oldest to youngest, shonkinite, mesosyenite, syenite, quartz syenite, potassic granite, carbonatite, carbonatite dikes, and late shonkinite dikes. The diverse physical properties of rocks that underlie the study area are well suited to geophysical investigations. Contrasts in radiogenic signatures between Paleoproterozoic crystalline basement, rocks of the Mesoproterozoic carbonatite body and the associated alkaline intrusive suite, Paleozoic carbonate rocks, Mesozoic granitoids, Tertiary volcanic rocks, and unconsolidated alluvium, for example, produce a distinctive pattern of radiometric anomalies that can aid in understanding the geologic framework and mineral resource potential of the eastern Mojave Desert. A high-resolution radiometric survey of Mountain Pass was flown by helicopter over parts of the Clark Mountain Range, Mescal Range, and Ivanpah Mountains. Aeroradiometric surveys measure the intensity and energy spectrum of gamma-ray radiation from the three most common naturally occurring radioelements: potassium ( 40 K), thorium ( 232 Th), and uranium ( 238 U). For 232 Th and 238 U, the source of the gamma-rays comes from their thallium ( 208 Tl) and bismuth ( 214 Bi) decay products, respectively, and, thus, concentrations for Th and U are referred to as “equivalent concentration,” assuming radioactive equilibrium. The concentrations of these radioelements can be used together to estimate changes in geochemistry and lithology. Carbonatite deposits typically have distinctive geophysical signatures because they are relatively dense, magnetic, and radiogenic. Specifically, the carbonatite and alkaline intrusive suite at Mountain Pass is ultrapotassic and contains relatively significant amounts of K, Th, and U, which can be delineated using airborne radiometric surveys.

California↗
USGS2009

Radionuclides in surface and groundwater

Unique among all the contaminants that adversely affect surface and water quality, radioactive compounds pose a double threat from both toxicity and damaging radiation. The extreme energy potential of many of these materials makes them both useful and toxic. The unique properties of radioactive materials make them invaluable for medical, weapons, and energy applications. However, mining, production, use, and disposal of these compounds provide potential pathways for their release into the environment, posing a risk to both humans and wildlife. This chapter discusses the sources, uses, and regulation of radioactive compounds in the United States, biogeochemical processes that control mobility in the environment, examples of radionuclide contamination, and current work related to contaminated site remediation.

Book chapter↗
USGS2009

Estimated use of water in Alabama in 2005

Water use in Alabama was about 9,958 million gallons per day (Mgal/d) during 2005. Estimates of withdrawals by source indicate that total surface-water withdrawals were about 9,467 Mgal/d (95 percent of the total withdrawals) and the remaining 491 Mgal/d (5 percent) were from ground water. More surface water than ground water was withdrawn for all categories except aquaculture, mining, and self-supplied residential. During 2005, estimated withdrawals by category and in descending order were: thermoelectric power, 8,274 Mgal/d; public supply, 802 Mgal/d; self-supplied industrial, 550 Mgal/d; irrigation, 161 Mgal/d; aquaculture, 75 Mgal/d; self-supplied residential, 39 Mgal/d; livestock, 28 Mgal/d; and mining, 28 Mgal/d. During 2005, about 83 percent of the water used in Alabama was for thermoelectric power to generate about 114,144 net gigawatt-hours of energy. Almost all of the thermoelectric-power water use (about 8,274 Mgal/d) was from surface water; nearly all of the water (98 percent) was used for once-through cooling, and most of that water was returned to a surface-water source. Public-supply and self-supplied residential withdrawals were about 8 percent of total water withdrawals and about 50 percent of total water withdrawals for all categories excluding thermoelectric power. The combined public-supply and self-supplied residential ground-water withdrawals were about 64 percent of total ground-water withdrawals for Alabama. Public-supply deliveries to residential customers were 41 percent of total public-supply withdrawals, or about 326 Mgal/d; combined industrial and commercial deliveries were 44 percent, or about 355 Mgal/d; and public use and losses accounted for the remaining 15 percent, or about 120 Mgal/d. Self-supplied industrial (550 Mgal/d) and mining (28 Mgal/d) withdrawals were about 6 percent of total water withdrawals and about 33 percent of total water withdrawals for all categories excluding thermoelectric power. Paper and allied products accounted for the largest self-supplied industrial surface-water withdrawals (301 Mgal/d), and chemical and allied products (12 Mgal/d) accounted for the largest ground-water withdrawals. Water withdrawals for the agricultural sector-irrigation (161 Mgal/d), aquaculture (75 Mgal/d), and livestock (28 Mgal/d)-were about 3 percent of total withdrawals and about 16 percent of total withdrawals for all categories excluding thermoelectric power. About 135,800 acres of crops, nursery stock, sod, and golf courses were irrigated in 2005. About 97 percent of these acres were irrigated with sprinkler irrigation systems. The statewide average application rate was 1.33 acre-feet per acre per year. The highest application rate, 3.74 acre-feet per acre per year, was for nursery stock. The largest total water withdrawals by county occurred in Limestone, Jackson, Colbert, and Mobile Counties, and were 60 percent of the total; these withdrawals primarily were used to meet the cooling needs at thermoelectric-power plants. Excluding thermoelectric power, the largest withdrawals by county were in Morgan, Mobile, Jefferson, Talladega, and Madison Counties. Water use was estimated at the hydrologic subbasin level for all categories except aquaculture, mining, and self-supplied residential. The Middle Tennessee-Elk subregion accounted for about 53 percent (5,185 Mgal/d) of the estimated total withdrawals by subbasin of 9,816 Mgal/d. About 92 percent of the water use in the Middle Tennessee-Elk subregion was for thermoelectric power, and more than 99 percent of the water was from surface water. Gross per capita use for all offstream uses was 2,185 gallons per day (gal/d) for the estimated 4.56 million Alabama residents in 2005. Public-supply per capita use was 199 gal/d for the estimated 4.04 million residents served by a public supplier; public-supplied residential per capita use was 81 gal/d. Self-supplied residential per capita use was 75 gal/d for the estimated 0.52 million self-supplied residential population. Average residential per capita use was 80 gal/d. Total water withdrawals decreased less than 1 percent from 9,990 Mgal/d in 2000 to 9,958 Mgal/d in 2005. Surface-water withdrawals decreased less than 5 percent from 9,950 Mgal/d in 2000 to 9,467 Mgal/d in 2005. In contrast, ground-water withdrawals increased about 12 percent from 440 Mgal/d in 2000 to 491 Mgal/d in 2005. By category, increases in irrigation (118 Mgal/d, about 274 percent), thermoelectric power (84 Mgal/d, about 1 percent), and aquaculture (65 Mgal/d, 620 percent) were offset by declines in self-supplied industrial (283 Mgal/d, about 34 percent), self-supplied residential (40 Mgal/d, about 50 percent); and public supply (32 Mgal/d, about 4 percent) from 2000 to 2005. Water use for livestock and mining was not estimated in 2000.

Scientific Investigations Report↗
USGS2020

Natural gas hydrates: Status of potential as an energy resource

Gas hydrate is a widespread naturally-occurring combination of water and natural gases. Gas hydrate is found in shallow sediments of deepwater regions of the continental margins and in areas of continuous permafrost. Where gas supply is sufficient and migration pathways connect gas sources to favorable reservoirs, gas hydrate can accumulate to resource densities that may be attractive for gas production. Global research on the potential commercial viability of gas extraction from gas hydrates continues, predominantly in Asia and in the United States, where current efforts focus on the controlled destabilization of high-saturation deposits housed in sand and/or silt-rich reservoirs. This chapter reviews the current state of gas hydrate resource exploration and appraisal, the most promising production approaches identified to date, and the likely technical challenges to commercial production.

Book chapter↗
USGS2013

Groundwater ages and mixing in the Piceance Basin natural gas province, Colorado

Reliably identifying the effects of energy development on groundwater quality can be difficult because baseline assessments of water quality completed before the onset of energy development are rare and because interactions between hydrocarbon reservoirs and aquifers can be complex, involving both natural and human processes. Groundwater age and mixing data can strengthen interpretations of monitoring data from those areas by providing better understanding of the groundwater flow systems. Chemical, isotopic, and age tracers were used to characterize groundwater ages and mixing with deeper saline water in three areas of the Piceance Basin natural gas province. The data revealed a complex array of groundwater ages (<10 to >50,000 years) and mixing patterns in the basin that helped explain concentrations and sources of methane in groundwater. Age and mixing data also can strengthen the design of monitoring programs by providing information on time scales at which water quality changes in aquifers might be expected to occur. This information could be used to establish maximum allowable distances of monitoring wells from energy development activity and the appropriate duration of monitoring.

Colorado↗
USGS2016

Trophic pathways supporting juvenile Chinook and Coho salmon in the glacial Susitna River, Alaska: patterns of freshwater, marine, and terrestrial resource use across a seasonally dynamic habitat mosaic

Contributions of terrestrial-, freshwater-, and marine-derived prey resources to stream fishes vary over time and space, altering the energy pathways that regulate production. In this study, we determined large-scale use of these resources by juvenile Chinook and coho salmon ( Oncorhynchus tshawytscha and Oncorhynchus kisutch , respectively) in the glacial Susitna River, Alaska. We resolved spatial and temporal trophic patterns among multiple macrohabitat types along a 97 km segment of the river corridor via stable isotope and stomach content analyses. Juvenile salmon were supported primarily by freshwater-derived resources and secondarily by marine and terrestrial sources. The relative contribution of marine-derived prey to rearing salmon was greatest in the fall within off-channel macrohabitats, whereas the contributions of terrestrial invertebrate prey were generally greatest during midsummer, across all macrohabitats. No longitudinal (upstream–downstream) diet pattern was discernable. These results highlight large-scale spatial and seasonal patterns of energy flow and the dynamic interplay of pulsed marine and terrestrial prey subsidies to juvenile Chinook and coho salmon in a large, complex, and relatively pristine glacial river.

Alaska↗
USGS2005

Sources of variability of evapotranspiration in California

The variability (1990–2002) of potential evapotranspiration estimates (ETo) and related meteorological variables from a set of stations from the California Irrigation Management System (CIMIS) is studied. Data from the National Climatic Data Center (NCDC) and from the Department of Energy from 1950 to 2001 were used to validate the results. The objective is to determine the characteristics of climatological ETo and to identify factors controlling its variability (including associated atmospheric circulations). Daily ETo anomalies are strongly correlated with net radiation ( R n ) anomalies, relative humidity (RH), and cloud cover, and less with average daily temperature ( T avg ). The highest intraseasonal variability of ETo daily anomalies occurs during the spring, mainly caused by anomalies below the high ETo seasonal values during cloudy days. A characteristic circulation pattern is associated with anomalies of ETo and its driving meteorological inputs, R n , RH, and T avg , at daily to seasonal time scales. This circulation pattern is dominated by 700-hPa geopotential height ( Z 700 ) anomalies over a region off the west coast of North America, approximately between 32° and 44° latitude, referred to as the California Pressure Anomaly (CPA). High cloudiness and lower than normal ETo are associated with the low-height (pressure) phase of the CPA pattern. Higher than normal ETo anomalies are associated with clear skies maintained through anomalously high Z 700 anomalies offshore of the North American coast. Spring CPA, cloudiness, maximum temperature ( T max ), pan evaporation ( E pan ), and ETo conditions have not trended significantly or consistently during the second half of the twentieth century in California. Because it is not known how cloud cover and humidity will respond to climate change, the response of ETo in California to increased greenhouse-gas concentrations is essentially unknown; however, to retain the levels of ETo in the current climate, a decline of R n by about 6% would be required to compensate for a warming of +3°C.

Journal of Hydrometeorology↗
USGS2013

Detecting channel riparian vegetation response to best-management-practices implementation in ephemeral streams with the use of spot high-resolution visible imagery

Heavily grazed riparian areas are commonly subject to channel incision, a lower water table, and reduced vegetation, resulting in sediment delivery above normal regimes. Riparian and in-channel vegetation functions as a roughness element and dissipates flow energy, maintaining stable channel geometry. Ash Creek, a tributary of the Bad River in western South Dakota contains a high proportion of incised channels, remnants of historically high grazing pressure. Best management practices (BMP), including off-stream watering sources and cross fencing, were implemented throughout the Bad River watershed during an Environmental Protection Agency (EPA) 319 effort to address high sediment loads. We monitored prairie cordgrass (Spartina pectinata Link) establishment within stream channels for 16 yr following BMP implementation. Photos were used to group stream reaches (n = 103) subjectively into three classes; absent (estimated < 5% cover; n = 64), present (estimated 5–40% cover; n = 23), and dense (estimated > 40% cover; n = 16) based on the relative amount of prairie cordgrass during 2010 assessments of ephemeral channels. Reaches containing drainage areas of 0.54 to 692 ha were delineated with the use of 2010 National Agriculture Imagery Program (NAIP) imagery. Normalized difference vegetation index (NDVI) values were extracted from 5 to 39 sample points proportional to reach length using a series of Satellite Pour l'Observation de la Terre (SPOT) satellite imagery. Normalized NDVI (nNDVI) of 2 152 sample points were determined from pre- and post-BMP images. Mean nNDVI values for each reach ranged from 0.33 to 1.77. ANOVA revealed significant increase in nNDVI in locations classified as present prairie cordgrass cover following BMP implementation. Establishment of prairie cordgrass following BMP implementation was successfully detected remotely. Riparian vegetation such as prairie cordgrass adds channel roughness that reduces the flow energy responsible for channel degradation.

South Dakota↗
USGS2001

Water-quality conditions during low flow in the lower Youghiogheny River basin, Pennsylvania, October 5-7, 1998

In October 1998, a chemical synoptic survey was conducted by the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, National Energy Technology Laboratory, in the Lower Youghiogheny River Basin in Pennsylvania to give a snapshot of present (1998) water quality during low-flow conditions. Water samples from 38 sites—12 mainstem sites, 22 tributaries, and 4 mine discharges that discharge directly to the Youghiogheny River—were used to identify sources of contaminants from mining operations. Specific conductance, water temperature, pH, and dissolved oxygen were measured in the field at each site and concentrations of major ions and trace elements were measured in the laboratory.z Unaccounted for gains and losses in streamflow were measured during the study. Unaccounted for losses in streamflow might be attributed to water loss through streambed fractures. Extensive mine tunnels are present in the basin and loss of water to these tunnels seems likely. Unaccounted for gains in streamflow may be from unmeasured tributaries or surface seeps, but most of the gains are suspected to come from artesian flow through fractures in the streambed from underground mine pools. Influent flows of rust-colored water were noted in some river sections. The pH values for all the samples collected during this survey were above 5.8, and most (33 of 38 samples) were above 7.0. Samples from the four mine-discharge sites also had pH values between 6.3 and 6.7. The lowest pH (5.8) was in a tributary, Galley Run. All 38 sampling sites had net alkalinity. The alkalinity load in the Youghiogheny River increased between Connellsville and McKeesport from 35 to 79 tons per day. Above Smithton, the measured alkalinity load in the Lower Youghiogheny River agreed well with the estimated alkalinity load. Below Smithton, measured alkalinity loads in the Lower Youghiogheny River are greater than calculated loads, resulting in unaccounted for gains in alkalinity. These gains are believed to be from seeps in the streambed. Approximately one-third of the load of total alkalinity in the Youghiogheny River at McKeesport is attributed to Sewickley Creek, which contributes 14 tons per day. Sulfate concentrations in the Youghiogheny River steadily increase from 33 milligrams per liter at Connellsville to 77 milligrams per liter near McKeesport. The measured concentrations of sulfate exceeded Pennsylvania water-quality standards at four tributary sites (Galley Run, Hickman Run, Sewickley Creek, and Gillespie Run) and all four mine-discharge sites but not at any main-stem sites. A large increase in sulfate load between West Newton and Sutersville can be attributed almost entirely to the contribution from Sewickley Creek (49 tons per day). Approximately 25 percent of the load measured between Connellsville and McKeesport is unaccounted for. These gains are believed to be from seeps in the streambed from underground mine pools. Similar patterns also were observed for loads of sodium, calcium, and magnesium. Unmeasured inputs from mine drainage are believed to be the source of these loads. Elevated concentrations (above background levels) of chemicals associated with drainage from coal-mining operations were measured in samples from tributaries, especially from Galley Run, Gillespie Run, and Sewickley Creek, and from the mine-discharge sites. The synoptic survey conducted for this study was successful in identifying generalized reaches of the Youghiogheny River where unaccounted for loads of constituents associated with mining activities are entering the river. However, the survey was not able to pinpoint the location of these loads. Remote-sensing techniques, such as thermal infrared imaging by the National Energy Technology Laboratory, could be useful for determining the precise locations of these inputs.

Water-Resources Investigations Report↗
USGS2010

Interpretation of surface flux measurements in heterogeneous terrain during the Monsoon '90 experiment

A network of 9-m-tall surface flux measurement stations were deployed at eight sparsely vegetated sites during the Monsoon '90 experiment to measure net radiation, Q , soil heat flux, G , sensible heat flux, H (using eddy correlation), and latent heat flux, λ E (using the energy balance equation). At four of these sites, 2-m-tall eddy correlation systems were used to measure all four fluxes directly. Also a 2-m-tall Bowen ratio system was deployed at one site. Magnitudes of the energy balance closure ( Q + G + H + λ E ) increased as the complexity of terrain increased. The daytime Bowen ratio decreased from about 10 before the monsoon season to about 0.3 during the monsoons. Source areas of the measurements are developed and compared to scales of heterogeneity arising from the sparse vegetation and the topography. There was very good agreement among simultaneous measurements of Q with the same model sensor at different heights (representing different source areas), but poor agreement among different brands of sensors. Comparisons of simultaneous measurements of G suggest that because of the extremely small source area, extreme care in sensor deployment is necessary for accurate measurement in sparse canopies. A recently published model to estimate fetch is used to interpret measurements of H at the 2 m and 9 m heights. Three sites were characterized by undulating topography, with ridgetops separated by about 200–600 m. At these sites, sensors were located on ridgetops, and the 9-m fetch included the adjacent valley, whereas the 2-m fetch was limited to the immediate ridgetop and hillside. Before the monsoons began, vegetation was mostly dormant, the watershed was uniformly hot and dry, and the two measurements of H were in close agreement. After the monsoons began and vegetation fully matured, the 2-m measurements of H were significantly greater than the 9-m measurements, presumably because the vegetation in the valleys was denser and cooler than on the ridgetops and hillsides. At one lowland site with little topographic relief, the vegetation was more uniform, and the two measurements of H were in close agreement during peak vegetation. Values of λ E could only be compared at two sites, but the 9-m values were greater than the 2-m values, suggesting λ E from the dense vegetation in the valleys was greater than elsewhere.

Water Environment Research↗
USGS2023

Fall migration, oceanic movement, and site residency patterns of eastern red bats (Lasiurus borealis) on the mid-Atlantic Coast

Along the mid-Atlantic coast of the United States, eastern red bats ( Lasiurus borealis ) are present during fall mating and migration, though little is currently known about most aspects of bat migration. To reveal migration patterns, and understand drivers of over-water flight, we captured and radio-tagged 115 eastern red bats using novel technology, and subsequently tracked and described their movements throughout the region. We compared over-water flight movements to randomly generated patterns using a use-availability framework, and subsequently used a generalized linear mixed effects model to assess the relationship of over-water flight to atmospheric variables. We used hidden Markov models to assess daily activity patterns and site residency. Most bats with long-distance movements traveled in a southwesterly direction, however path vectors were often oriented interior toward the continental landmass rather than along the coastline. We observed that some bats transited wide sections of the Chesapeake and Delaware bays, confirming their ability to travel across large water bodies. This over-water flight typically occurred in the early hours of the night and during favorable flying conditions. If flight over large water bodies is a proxy for over-ocean flight, then collision risk at offshore wind turbines – a major source of migratory bat fatalities – may be linked nightly to warm temperatures that occur early in the fall season. Risk, then, may be somewhat predictable and manageable with mitigation options linking wind-energy operation to weather conditions and seasonality.

Delaware, Maryland, New Jersey, Virginia↗
USGS2001

The Putumayo-Oriente-Maranon Province of Colombia, Ecuador, and Peru; Mesozoic-Cenozoic and Paleozoic petroleum systems

This report is an evaluation of oil and gas resources for petroleum systems of the Putumayo-Oriente-Maranon province of Columbia, Ecuador, and Peru. This assessment is a product of the World Energy Project of the U.S. Geological Survey, under the direction of Thomas Ahlbrandt. Described in this explanation of the petroleum geology of the Putumayo-Oriente-Maranon province are thermal maturation of hydrocarbon source rocks, primary reservoir formations, areas and volumes of oil and (or) gas production, and the history of exploration. Complete oil and gas resource assessment results are planned for a later publication, although some data and results are contained in this report.

Data Series↗
USGS1994

Simulated effects of projected withdrawals from the Wenonah-Mount Laurel aquifer on ground-water levels in the Camden, New Jersey, area and vicinity

The Wenonah-Mount Laurel aquifer is being considered as a potential source of future water supply for the Camden, New Jersey, area. The deeper Potomac- Raritan-Magothy aquifer system is currently the major major source of water supply for the area, but its use may be curtailed or reduced by 35 percent of 1983 withdrawals through its designation by the New Jersey Department of Environmental Protection and Energy as "Water Supply Critical Area#2." Withdrawals from the Wenonah-Mount Laurel aquifer currently (1989) total about 7 million gallons per day. The anticipated use of this aquifer by communities with access to it, as an alternative supply, could increase to more than 14 million gallons per day by 2020. If the communities of Clayton and Glassboro decrease their withdrawals from the Potomac-Raritan-Magothy aquifer system by 50 percent or cease them entirely because of their proximity to saline water, the use of Wenonah-Mount Laurel aquifer could increase to greater than 15 million gallons per day by 2020. Simulation of the ground-water system indicates that the projected increase in withdrawals will cause cones of depression in the potentiometric surface of the Wenonah-Mount Laurel aquifer in the Camden metro- politan area by 2020 that extend to depths ranging from 10 feet above sea level to 60 feet below sea level. This represents a secline of about 40 to 100 feet thr 1990 conditions. Withdrawals in northeastern Burlington County will cause a large cone of depression that, by 2020, will extend to depths of about 220 feet below sea level, represent- ing a decline of about 140 feet from 1990 conditions. Simulation results indicate that water levels in the Wenonah-Mount Laurel aquifer near the Salem Nuclear Power Plant are somewhat insensitive to withdrawals elsewhere in the aquifer. In some areas, especially in Burlington County, the cones of depression have developed in proximity to the aquifer-outcrop area and could induce infiltration from streams crossing the outcrop. Because of the hydraulic connection to adjacent aquifers, future management plans need to be developed in a compre- hensive manner with regard to all aquifers. Further study of the aquifer in Salem County could provide additional information on the hydraulic connection to Delaware Bay and the potential for saltwater intrusion.

New Jersey↗
USGS2012

Lahar hazard zones for eruption-generated lahars in the Lassen Volcanic Center, California

Lahar deposits are found in drainages that head on or near Lassen Peak in northern California, demonstrating that these valleys are susceptible to future lahars. In general, lahars are uncommon in the Lassen region. Lassen Peak's lack of large perennial snowfields and glaciers limits its potential for lahar development, with the winter snowpack being the largest source of water for lahar generation. The most extensive lahar deposits are related to the May 1915 eruption of Lassen Peak, and evidence for pre-1915 lahars is sparse and spatially limited. The May 1915 eruption of Lassen Peak was a small-volume eruption that generated a snow and hot-rock avalanche, a pyroclastic flow, and two large and four smaller lahars. The two large lahars were generated on May 19 and 22 and inundated sections of Lost and Hat Creeks. We use 80 years of snow depth measurements from Lassen Peak to calculate average and maximum liquid water depths, 2.02 meters (m) and 3.90 m respectively, for the month of May as estimates of the 1915 lahars. These depths are multiplied by the areal extents of the eruptive deposits to calculate a water volume range, 7.05-13.6x10 6 cubic meters (m 3 ). We assume the lahars were a 50/50 mix of water and sediment and double the water volumes to provide an estimate of the 1915 lahars, 13.2-19.8x10 6 m 3 . We use a representative volume of 15x106 m 3 in the software program LAHARZ to calculate cross-sectional and planimetric areas for the 1915 lahars. The resultant lahar inundation zone reasonably portrays both of the May 1915 lahars. We use this same technique to calculate the potential for future lahars in basins that head on or near Lassen Peak. LAHARZ assumes that the total lahar volume does not change after leaving the potential energy, H/L , cone (the height of the edifice, H , down to the approximate break in slope at its base, L ); therefore, all water available to initiate a lahar is contained inside this cone. Because snow is the primary source of water for lahar generation, we assume that the maximum historical water equivalent, 3.90 m, covers the entire basin area inside the H/L cone. The product of planimetric area of each basin inside the H/L and the maximum historical water equivalent yields the maximum water volume available to generate a lahar. We then double the water volumes to approximate maximum lahar volumes. The maximum lahar volumes and an understanding of the statistical uncertainties inherent to the LAHARZ calculations guided our selection of six hypothetical volumes, 1, 3, 10, 30, 60, and 90x10 6 m 3 , to delineate concentric lahar inundation zones. The lahar inundation zones extend, in general, tens of kilometers away from Lassen Peak. The small, more-frequent lahar inundation zones (1 and 3x10 6 m 3 ) are, on average, 10 km long. The exceptions are the zones in Warner Creek and Mill Creek, which extend much further. All but one of the small, more-frequent lahar inundation zones reach outside of the Lassen Volcanic National Park boundary, and the zone in Mill Creek extends well past the park boundary. All of the medium, moderately frequent lahar inundation zones (10 and 30x10 6 m 3 ) extend past the park boundary and could potentially impact the communities of Viola and Old Station and State Highways 36 and 44, both north and west of Lassen Peak. The approximately 27-km-long on average, large, less-frequent lahar inundation zones (60 and 90x10 6 m 3 ) represent worst-case lahar scenarios that are unlikely to occur. Flood hazards continue downstream from the toes of the lahars, potentially affecting communities in the Sacramento River Valley.

California↗
USGS2012

Estimating the benefits of land imagery in environmental applications: a case study in nonpoint source pollution of groundwater

Moderate-resolution land imagery (MRLI) is crucial to a more complete assessment of the cumulative, landscape-level effect of agricultural land use and land cover on environmental quality. If this improved assessment yields a net social benefit, then that benefit reflects the value of information (VOI) from MRLI. Environmental quality and the capacity to provide ecosystem services evolve because of human actions, changing natural conditions, and their interaction with natural physical processes. The human actions, in turn, are constrained and redirected by many institutions and regulations such as agricultural, energy, and environmental policies. We present a general framework for bringing together sociologic, biologic, physical, hydrologic, and geologic processes at meaningful scales to interpret environmental implications of MRLI applications. We set out a specific application using MRLI observations to identify crop planting patterns and thus estimate surface management activities that influence groundwater resources over a regional landscape. We tailor the application to the characteristics of nonpoint source groundwater pollution hazards in Iowa to illustrate a general framework in a land use-hydrologic-economic system. In the example, MRLI VOI derives from reducing the risk of both losses to agricultural production and damage to human health and other consequences of contaminated groundwater.

Book chapter↗
USGS2007

An Evaluation of the USGS World Petroleum Assessment 2000 - Supporting Data

Introduction In June 2000, the U.S. Geological Survey (USGS) published the results of a world petroleum assessment (exclusive of the United States), based on data current through 1995 (U.S. Geological Survey World Energy Assessment Team, 2000). The assessment included the volumes of undiscovered crude oil and natural gas estimated to have the potential to be added to reserves in a 30-year time frame (to 2025). Klett and others (2005) compared the actual additions to reserves as reported from January 1996 to December 2003 (IHS Energy, 2003) with those estimates, apportioned to the 1996-2003 period (27 percent of the 30-year time frame). The present report (1) provides tabular data, not included in the 2005 report by Klett and others, that support the graphical displays and (2) briefly summarizes the interpretations and conclusions presented in the 2005 report. Approximately 28 percent of the additions to oil reserves by reserve growth and approximately 11 percent of the estimated undiscovered oil volumes that were estimated for the World Petroleum Assessment 2000 (U.S. Geological Survey World Energy Assessment Team, 2000) were realized in the 8 years since that assessment. Slightly more than half of the estimated additions to gas reserves by reserve growth and approximately 10 percent of the estimated undiscovered gas volumes were realized. Between 1995 and 2003, growth of oil reserves in previously discovered fields exceeded new-field discoveries as a source of global additions to reserves of conventional oil by a factor of about 3 to 1. The greatest amount of reserve growth for crude oil was in the Middle East and North Africa, whereas the greatest contribution from new-field discoveries was in Sub-Saharan Africa. The greatest amount of reserve growth for natural gas was in the Middle East and North Africa, whereas the greatest contribution from new-field discoveries was in the Asia Pacific region. On an energy-equivalent basis, volumes of new gas field discoveries exceeded new oil field discoveries. The graphs are based on the data listed in tables 1 and 2.

Open-File Report↗
USGS2026

Uncertainty quantification of geologic energy storage in depleted gas reservoirs using material balance equations embedded in a hierarchical errors-in-variables model

The storage potential for gas in geologic settings, such as depleted hydrocarbon reservoirs and solution-mined salt caverns, is becoming salient to future energy infrastructure planning. Technologies such as carbon capture, utilization, and storage, carbon dioxide-enhanced oil recovery, and natural gas and hydrogen storage help meet growing energy demands, reduce carbon emissions to meet climate goals, and provide energy security amid geopolitical uncertainties. Therefore, estimates of underground gas storage capacity could be useful for efficiently navigating the energy transitions. Material balance is a fundamental method in reservoir engineering for estimating original gas in place and potential storage capacity at the scale necessary for national assessments of subsurface pore space resources. However, the deterministic method cannot accommodate multiple data sources or quantify uncertainty in predictions. In this study, a method that embeds material balance equations within a hierarchical errors-in-variables model is proposed which allows the estimation of the distributions of reservoir properties needed for assessments. Uncertainties associated with these reservoir properties have traditionally been expert-elicited, whereas the uncertainty estimates from the proposed models are data-driven. Capacity and uncertainty estimates can be used in a probabilistic resource assessment, supplementing information traditionally used by assessors or even replacing this expert elicitation step when data are unavailable. Various regression models are compared in a case study of the Michigan Basin, a large contributor to the United States’ current natural gas storage capacity. In particular, errors-in-variables models help ameliorate regression dilution and can quantify uncertainty in predictions of pressure in addition to storage capacity. Overfitting is addressed by quantifying generalization error and model averaging in simple and stratified cross-validation against reported working gas capacity, representing the varying quality and quantity of available data. Incorporating a statistical framework into existing numerical methods in reservoir engineering can improve the quality of estimation, and in particular, this method brings rigor to uncertainty quantification as part of a larger effort by the U.S. Geological Survey to assess domestic energy gas storage resources in depleted hydrocarbon reservoirs.

Mathematical Geosciences↗