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At least 991 records · Page 55Linked to original sources
USGS2009

Combined use of frequency‐domain electromagnetic and electrical resistivity surveys to delineate the freshwater/saltwater interface near saline lakes in the Nebraska Sand Hills, Nebraska, USA

We investigate the use of frequency‐domain electromagnetic (FDEM) and electrical resistivity (ER) surveys for rapid and detailed characterization of the direction of lake‐aquifer fluxes and the configuration of salt plumes generated from saline lakes. This methodology was developed and applied at several lakes in the Nebraska Sand Hills, Nebraska, in an area with both freshwater and saline lakes hydraulically connected to the freshwater surficial aquifer. The FDEM survey was conducted by mounting the instrument on a fiberglass cart towed by an all‐terrain vehicle. The towed FDEM surveys covered about 25 km per day and served as a reconnaissance method for choosing locations for the more quantitative and detailed ER surveys. Around the saline lakes, areas with high electrical conductivity are consistent with the regional direction of ground‐water flow. Lower electrical conductivity was measured around the freshwater lakes with anomalies correlating to a paleovalley axis inferred from previous studies. The efficacy of this geophysical approach is attributed to: (1) significant contrast in electrical conductivity between freshwater and saltwater, (2) near‐surface location of the freshwater/saltwater interface, (3) minimal cultural interference, and (4) relative homogeneity of the aquifer materials.

Nebraska↗
USGS2014

Comparisons of genetic diversity in captive versus wild populations of the federally endangered Quino checkerspot butterfly ( Euphydryas editha quino Behr; Lepidoptera: Nymphalidae)

Captive populations can play a significant role in threatened and endangered species management. An important consideration when developing and managing captive populations, however, is the maintenance of genetic diversity to ensure that adequate variation exists to avoid the negative consequences of inbreeding. In this investigation, we compared genetic diversity patterns within captive and wild populations of the federally endangered Quino checkerspot butterfly (Euphydryas editha quino Behr [Lepidoptera: Nymphalidae]), a taxon with a restricted distribution to chaparral and sage shrublands within Riverside and San Diego counties, California. Our analyses revealed that medium to high-frequency alleles from the wild populations were also present in the captive populations. While there was no significant difference in genetic diversity as quantified by expected heterozygosity, the captive populations showed tendencies toward significantly lower allelic richness than their wild counterparts. Given that alleles from the wild populations were occasionally not detected in captive populations, periodic incorporation of new wild specimens into the captive population would help ensure that allelic diversity is maintained to the extent possible. If performed in advance, genetic surveys of wild populations may provide the clearest insights regarding the number of individuals needed in captivity to adequately reflect wild populations.

California↗
USGS2018

The bees (Hymenoptera: Apoidea) of Louisiana: an updated, annotated checklist

An annotated checklist is provided for 243 species and subspecies of bees collected from or thought to occur in the state of Louisiana, where 163 are confirmed records, 46 are probable records, and 34 are possible records. We also list twelve records considered to be “dubious” because of the absence of supporting collection data and extralimital reported ranges. Data on parish localities, seasonality, and floral records are provided when available. Specimen data are provided from two separate surveys in the state, one focusing on the fauna of longleaf pine savannas and another focusing on Cajun prairie habitat in southwestern Louisiana. Data from a previous annotated checklist of bees from longleaf pine savannas (Bartholomew et al. 2006) are included, as well as online records from the Discover Life checklist (Ascher and Pickering 2016), and bee holdings of the Louisiana State Arthropod Museum (LSAM, Louisiana State University, Baton Rouge, LA).We highlight the role that this museum and similar small institutional insect collections play in documenting faunas on local and regional scales.

Louisiana↗
USGS2014

Locking horns with Hawai‘i’s non-native ungulate issues

Conservation and management interests for sustained-yield hunting of non-native ungulates in Hawai‘i have conflicted with the conservation of native biota for several decades. Hawaiian ecosystems evolved in the absence of large mammals and all currently hunted animals in Hawai‘i are non-native species. The best-studied aspects of Hawai‘i’s ungulates have dealt primarily with direct negative effects on native biota in natural areas, but there has been little research in population dynamics for sustained-yield management. Ungulates have been removed from approximately 750 km2 throughout the Hawaiian Islands to protect these natural areas, thereby reducing the amount of land area available for hunting activities and the maintenance of game populations. At the same time, unauthorized introductions of additional wild ungulate species between Hawaiian Islands have recently increased in frequency. The majority of hunting activities are of feral domestic livestock species for subsistence purposes, which typically do not generate sufficient revenue to offset costs of game management. Moreover, bag limits and seasons are generally not determined from biological criteria because harvest reporting is voluntary and game populations are rarely monitored. Consequently, ungulate populations cannot be managed for any particular level of abundance or other objectives. Research and monitoring which emphasize population dynamics and productivity would enable more precisely regulated sustained-yield game management programs and may reduce potential conflicts with the conservation of native biota.

Hawai'i↗
USGS2015

Land subsidence in the San Joaquin Valley, California, USA, 2007-14

Rapid land subsidence was recently measured using multiple methods in two areas of the San Joaquin Valley (SJV): between Merced and Fresno (El Nido), and between Fresno and Bakersfield (Pixley). Recent land-use changes and diminished surface-water availability have led to increased groundwater pumping, groundwater-level declines, and land subsidence. Differential land subsidence has reduced the flow capacity of water-conveyance systems in these areas, exacerbating flood hazards and affecting the delivery of irrigation water. Vertical land-surface changes during 2007–2014 were determined by using Interferometric Synthetic Aperture Radar (InSAR), Continuous Global Positioning System (CGPS), and extensometer data. Results of the InSAR analysis indicate that about 7600 km 2 subsided 50–540 mm during 2008–2010; CGPS and extensometer data indicate that these rates continued or accelerated through December 2014. The maximum InSAR-measured rate of 270 mm yr −1 occurred in the El Nido area, and is among the largest rates ever measured in the SJV. In the Pixley area, the maximum InSAR-measured rate during 2008–2010 was 90 mm yr −1 . Groundwater was an important part of the water supply in both areas, and pumping increased when land use changed or when surface water was less available. This increased pumping caused groundwater-level declines to near or below historical lows during the drought periods 2007–2009 and 2012–present. Long-term groundwater-level and land-subsidence monitoring in the SJV is critical for understanding the interconnection of land use, groundwater levels, and subsidence, and evaluating management strategies that help mitigate subsidence hazards to infrastructure while optimizing water supplies.

California↗
USGS2015

Examples of deformation-dependent flow simulations of conjunctive use with MF-OWHM

The dependency of surface- and groundwater flows and aquifer hydraulic properties on deformation induced by changes in aquifer head is not accounted for in the standard version of MODFLOW. A new USGS integrated hydrologic model, MODFLOW-OWHM, incorporates this dependency by linking subsidence and mesh deformation with changes in aquifer transmissivity and storage coefficient, and with flows that also depend on aquifer characteristics and land-surface geometry. This new deformation-dependent approach is being used for the further development of the integrated Central Valley hydrologic model (CVHM) in California. Preliminary results from this application and from hypothetical test cases of similar systems show that changes in canal flows, stream seepage, and evapotranspiration from groundwater (ET gw ) are sensitive to deformation. Deformation feedback has been shown to also have an indirect effect on conjunctive surface- and groundwater use components with increased stream seepage and streamflows influencing surface-water deliveries and return flows. In the Central Valley model, land subsidence may significantly degrade the ability of the major canals to deliver surface water from the Delta to the San Joaquin and Tulare basins. Subsidence can also affect irrigation demand and ET gw , which, along with altered surface-water supplies, causes a feedback response resulting in changed estimates of groundwater pumping for irrigation. This modeling feature also may improve the impact assessment of dewatering-induced land subsidence/uplift (following irrigation pumping or coal-seam gas extraction) on surface receptors, inter-basin transfers, and surface infrastructure integrity.

Proceedings of the International Association of Hy↗
USGS2018

Remote sensing vegetation index methods to evaluate changes in greenness and evapotranspiration in riparian vegetation in response to the Minute 319 environmental pulse flow to Mexico

During the spring of 2014, 130 million m 3 of water were released from the United States' Morelos Dam on the lower Colorado River to Mexico, allowing water to reach the Gulf of California for the first time in 13 years. Our study assessed the effects of water transfer or ecological environmental flows from one nation to another, using remote sensing. Spatial applications for water resource evaluation are important for binational, integrated water resources management and planning for the Colorado River, which includes seven basin states in the US plus two states in Mexico. Our study examined the effects of the historic binational experiment (the Minute 319 agreement) on vegetative response along the riparian corridor. We used 250 m Moderate Resolution Imaging Spectroradiometer (MODIS), Enhanced Vegetation Index (EVI) and 30 m Landsat 8 satellite imagery to track evapotranspiration (ET) and the normalized difference vegetation index (NDVI). Our analysis showed an overall increase in NDVI and evapotranspiration (ET) in the year following the 2014 pulse, which reversed a decline in those metrics since the last major flood in 2000. NDVI and ET levels decreased in 2015, but were still significantly higher ( P < 0.001) than pre-pulse (2013) levels. Preliminary findings show that the decline in 2015 persisted into 2016 and 2017. We continue to analyse results for 2018 in comparison to short-term (2013–2018) and long-term (2000–2018) trends. Our results support the conclusion that these environmental flows from the US to Mexico via the Minute 319 “pulse” had a positive, but short-lived (1 year), impact on vegetation growth in the delta.

Colorado River Delta↗
USGS2020

Mitigating land subsidence in the Coachella Valley, California, USA: An emerging success story

Groundwater has been a major source of agricultural, municipal, and domestic water supply since the early 1920s in the Coachella Valley, California, USA. Land subsidence, resulting from aquifer-system compaction and groundwater-level declines, has been a concern of the Coachella Valley Water District (CVWD) since the mid-1990s. As a result, the CVWD has implemented several projects to address groundwater overdraft that fall under three categories – groundwater substitution, conservation, and managed aquifer-recharge (MAR). The implementation of three projects in particular – replacing groundwater extraction with surface water from the Colorado River and recycled water (Mid-Valley Pipeline project), reducing water usage by tiered-rate costs, and increasing groundwater recharge at the Thomas E. Levy Groundwater Replenishment Facility – are potentially linked to markedly improved groundwater levels and subsidence conditions, including in some of the historically most overdrafted areas in the southern Coachella Valley. Groundwater-level and subsidence monitoring have tracked the effect these projects have had on the aquifer system. Prior to about 2010, water levels persistently declined, and some had reached historically low levels by 2010. Since about 2010, however, groundwater levels have stabilized or partially recovered, and subsidence has stopped or slowed substantially almost everywhere it previously had been observed; uplift was observed in some areas. Furthermore, results of Interferometric Synthetic Aperture Radar analyses for 1995–2017 indicate that as much as about 0.6 m of subsidence occurred; nearly all of which occurred prior to 2010. Continued monitoring of water levels and subsidence is necessary to inform the CVWD about future mitigation measures. The water management strategies implemented by the CVWD can inform managers of other overdrafted and subsidence-prone basins as they seek solutions to reduce overdraft and subsidence.

California↗
USGS2024

Paddlefish movement and dam passage in the Ohio and Kanawha Rivers, West Virginia

The Paddlefish ( Polyodon spathula ), a large-bodied and highly migratory species of large river systems, has experienced population declines or extirpation in parts of its native range. As an effort to reestablish a Paddlefish population in the Ohio River of West Virginia, the West Virginia Division of Natural Resources has stocked fingerling Paddlefish in the previous two decades. Post-stocking studies could assess the status of the reintroduced population, which includes collecting information on their seasonal movements and dam passage frequency through navigation dams of the Ohio and Kanawha Rivers. Using acoustic telemetry techniques, we monitored seasonal movements and assessed dam passage of five Paddlefish in the Robert C. Byrd Pool of the Ohio and Kanawha rivers. Paddlefish were highly mobile with two individuals using the entire R.C. Byrd Pool during the 11-month study period. Most movements occurred during the expected spawning period of April and May, where all individuals frequented the upper section of the pool in the Kanawha River. Downstream passage was documented for one individual at the R.C. Byrd lock during July 2023, but no evidence of upstream passage was documented for the locks at Racine (Ohio River) or Winfield (Kanawha River). Tagging of additional Paddlefish would be beneficial to increase sample size for future assessments and continue efforts toward the long-term conservation and management of Ohio River Paddlefish.

West Virginia↗
USGS2015

Geology and hydrocarbon potential of the Hartford-Deerfield Basin, Connecticut and Massachusetts

The Hartford-Deerfield basin, a Late Triassic to Early Jurassic rift basin located in central Connecticut and Massachusetts, is the northernmost basin of the onshore Mesozoic rift basins in the eastern United States. The presence of asphaltic petroleum in outcrops indicates that at least one active petroleum system has existed within the basin. However, to-date oil and gas wells have not been drilled in the basin to test any type of petroleum trap. There are good to excellent quality source rocks (up to 3.8% present day total organic carbon) within the Jurassic East Berlin and Portland formations. While these source rock intervals are fairly extensive and at peak oil to peak gas stages of maturity, individual source rock beds are relatively thin (typically less than 1 m) based solely on outcrop observations. Potential reservoir rocks within the Hartford-Deerfield basin are arkosic conglomerates, pebbly sandstones, and finer grained sandstones, shales, siltstones, and fractured igneous rocks of the Triassic New Haven and Jurassic East Berlin and Portland formations (and possibly other units). Sandstone porosity data from 75 samples range from less than 1% to 21%, with a mean of 5%. Permeability is equally low, except around joints, fractures, and faults. Seals are likely to be unfractured intra-formational shales and tight igneous bodies. Maturation, generation, and expulsion likely occurred during the late synrift period (Early Jurassic) accentuated by an increase in local geothermal gradient, igneous intrusions, and hydrothermal fluid circulation. Migration pathways were likely along syn- and postrift faults and fracture zones. Petroleum resources, if present, are probably unconventional (continuous) accumulations as conventionally accumulated petroleum is likely not present in significant volumes.

Connecticut, Massachusetts↗
USGS2015

Examination of the Reelfoot Rift Petroleum System, south-central United States, and the elements that remain for potential exploration and development

The Reelfoot rift is one segment of a late Proterozoic(?) to early Paleozoic intracontinental rift complex in the south-central United States. The rift complex is situated beneath Mesozoic to Cenozoic strata of the Mississippi embayment of southeastern Missouri, northeastern Arkansas, and western Tennessee and Kentucky. The rift portion of the stratigraphic section consists primarily of synrift Cambrian and Ordovician strata, capped by a postrift sag succession of Late Ordovician to Cenozoic age. Potential synrift source rocks have been identified in the Cambrian Elvins Shale. Thermal maturity of Paleozoic strata within the rift ranges from the oil window to the dry gas window. Petroleum generation in Elvins source rocks likely occurred during the middle to late Paleozoic. Upper Cretaceous sedimentary rocks unconformably overlie various Paleozoic units and define the likely upper boundary of the petroleum system. No production has been established in the Reel-foot rift. However, at least nine of 22 exploratory wells have reported petroleum shows, mainly gas shows with some asphalt or solid hydrocarbon residue. Regional seismic profiling shows the presence of two large inversion structures (Blytheville arch and Pascola arch). The Blytheville arch is marked by a core of structurally thickened Elvins Shale, whereas the Pascola arch reflects the structural uplift of a portion of the entire rift basin. Structural uplift and faulting within the Reelfoot rift since the late Paleozoic appear to have disrupted older conventional hydrocarbon traps and likely spilled any potential conventional petroleum accumulations. The remaining potential resources within the Reelfoot rift are likely shale gas accumulations within the Elvins Shale; however, reservoir continuity and porosity as well as pervasive faulting appear to be significant future challenges for explorers and drillers.

GCSSEPM Foundation Perkins-Rosen Research Conferen↗
USGS2015

Geology and hydrocarbon potential of the Dead Sea Rift Basins of Israel and Jordan

Following its middle Miocene inception, numerous basins of varying lengths and depths developed along the Dead Sea fault zone, a large continental transform plate boundary. The modern day left-lateral fault zone has an accumulated left-lateral offset of 105 to 110 km (65 to 68 mi). The deepest basin along the fault zone, the Lake Lisan or Dead Sea basin, reaches depths of 7.5 to 8.5 km (24,500 ft to 28,000 ft), and shows evidence of hydrocarbons. The basins are compartmentalized by normal faulting associated with rapid basin subsidence and, where present, domal uplift accompanying synrift salt withdrawal. The stratigraphy of the fault zone is composed of a thick pre-wrench interval of early Tertiary to Precambrian strata overlain by a syn-wrench section of Miocene to Recent sediments. The main potential source rock is the pre-wrench Cretaceous Maastrichtian Ghareb Formation (and equivalents), which has a total organic carbon (TOC) content measurement of 8 to 18%. Lesser potential source rocks may also be found in the Pleistocene, Cretaceous (Turonian), Jurassic (Oxfordian&ndash;Callovian), and Triassic (Ladinian&ndash;Carnian). Geochemical analyses indicate that the source of all oils, asphalts, and tars recovered in the Lake Lisan basin is the Ghareb Formation. Geothermal gradients along the Dead Sea fault zone vary from basin to basin. Syn-wrench potential reservoir rocks are highly porous and permeable, whereas pre-wrench strata commonly exhibit lower porosity and permeability. Biogenic gas has been produced from Pleistocene reservoirs. Potential sealing intervals may be present in Neogene evaporites and tight lacustrine limestones and shales. Simple structural traps are not evident; however, subsalt traps may exist. Unconventional source rock reservoir potential has not been tested.

GCSSEPM Foundation Perkins-Rosen Research Conferen↗
USGS2023

Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae and Platypodinae) associated with rapid ohia death and mixed Metrosideros polymorpha forests on the Island of Kauai, Hawaii

Xyleborini (Coleoptera: Curculionidae) beetles on the island of Kauaʻi, Hawaiʻi, are of interest due to their role in the fungal disease complex, rapid ʻōhiʻa death (ROD), and the unique radiation of endemic ambrosia beetles found across the Hawaiian archipelago. We investigated the status of RODassociated and native ambrosia beetles on Kauaʻi by rearing beetles from bolts collected from ROD-Ceratocystis infested ʻōhiʻa lehua (ʻōhiʻa; Metrosideros polymorpha) trees and trapping in mixed ʻōhiʻa forests. Beetles associated with ROD on Kauaʻi include Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xyleborus perforans, Xylosandrus crassiusculus, and Crossotarsus externedentatus. Xyleborus perforans was most abundant in ʻōhiʻa bolts followed by Xyleborus ferrugineus. From trap captures, we identified new island records of the native Xyleborus beetles including Xyleborus dubiosus, Xyleborus oahuensis, and Xyleborus tantalus. Xylosandrus crassiusculus was most abundant in traps. Additional work could contribute to understanding and mitigating the spread of ROD on Kauaʻi and to documenting the endemic Xyleborus beetles.

Hawaii↗
USGS1974

Dieldrin and DDT: accumulation from water and food by lake trout (Salvelinus namaycush) in the laboratory

In the laboratory we measured the amounts of dieldrin and p,p'DDT accumulated by fish from contaminated water and food to determine how fish from Lake Michigan accumulate high concentrations of these insecticides from an environment where the concentrations in water are generally less than 0.01 ppb. Eight groups of yearling lake trout (Salvelinus namaycush) were exposed to different combinations of dieldrin and p,p'DDT in water and food. Concentrations of dieldrin and p,p'DDT ranged from 0.006 to 0.010 ppb in water and from 1,700 to 2,300 ppb in food (Oregon moist pellets). After 152 days of exposure to insecticides in water, fish had accumulated an average of 478 ppb dieldrin or 352 ppb p,p'DDT. Fish exposed to dieldrin and p,p'DDT in food accumulated 470 and 648 ppb, respectively. However, it was difficult to determine exactly how much of either insecticide was accumulated from the food because trace amounts (0.003-0.004 ppb) had leached from food or feces. After exposure to the insecticide was terminated, fish eliminated dieldrin at a much faster rate than p,p'DDT. In fish exposed to a combination of dieldrin and p,p'DDT in water and then held for 125 days in uncontaminated water, the total amount of dieldrin (I?g) declined 89%, but the total amount of p,p'DDT remained unchanged. We used data from this study to estimate how much p,p'DDT adult Lake Michigan coho salmon (Oncorhynchus kisutch) accumulated from water and from food during a 104-day period (May-August 1968). The estimates suggest that during these months coho salmon accumulated most of the body burden of p,p'DDT from food.

Proceedings of the Conference on Great Lakes Resea↗
USGS1972

Seasonal population characteristics of the opossum shrimp, Mysis relicta, in southeastern Lake Michigan, 1970-71

This study of depth distribution, abundance, growth, reproduction and standing crop of the opossum shrimp, Mysis relicta, in southeastern Lake Michigan was based on monthly samples collected from August 1970 through July 1971 (except February and March). Population density was usually low at 10-20 fathoms, moderate at 25-30 fathoms and relatively high at 35 fathoms and deeper. Abundance was highest in midsummer and lowest in December. Free-living mysids were 3-25 mm long. Average growth rate was 1 mm per month. At maximum lengths, females were longer than males. Weight increased as approximately the cube of the length. The population consisted mostly of juveniles during summer and autumn and subadults and adults in winter and spring. Sizable numbers of adults apparently moved to relatively shallow water (10-35 fathoms) in winter, where they bred and released their young. In deeper water (40 fathoms or more), some reproduction occurred throughout the year. Most recruitment was in April and May. Standing crop ranged as high as 50 kg per hectare. Mysis apparently has a one-year life cycle in southeastern Lake Michigan.

Proceedings of the 15th Conference on Great Lakes ↗
USGS1984

Water quality in the Gillham Lake-Cossatot River system during dry and wet periods

Water samples were collected in the Cossatot River-Gillham Lake system during an extended dry period and after heavy rains to determine the spatial variations in certain water quality characteristics. Of particular interest was the influence of the reservoir discharge on the water quality of the tailwater compared with the effects of four tributaries entering the tailwater below the reservoir. The water quality of the Cossatot River below Gillman Lake at low-flow (dry periods) and during the first 3 days after heavy rainfall (wet period) was influenced more by the tributaries entering the tailwater than by the reservoir water release. We estimated, however, that the amount of particulate inorganic matter released to the tailwater from the reservoir after the initial 3-day wet period would be greater than the amounts entering the tailwater from the tributaries.

Arkansas Academy of Science Proceedings↗