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Sample records for aecl chalk river

  1. Radiochemistry Lab Decommissioning and Dismantlement. AECL, Chalk River Labs, Ontario, Canada

    SciTech Connect

    Kenny, Stephen

    2008-01-15

    Atomic Energy of Canada (AECL) was originally founded in the mid 1940's to perform research in radiation and nuclear areas under the Canadian Defense Department. In the mid 50's The Canadian government embarked on several research and development programs for the development of the Candu Reactor. AECL was initially built as a temporary site and is now faced with many redundant buildings. Prior to 2004 small amounts of Decommissioning work was in progress. Many reasons for deferring decommissioning activities were used with the predominant ones being: 1. Reduction in radiation doses to workers during the final dismantlement, 2. Development of a long-term solution for the management of radioactive wastes in Canada, 3. Financial constraints presented by the number of facilities shutdown that would require decommissioning funds and the absence of an approved funding strategy. This has led to the development of a comprehensive decommissioning plan that is all inclusive of AECL's current and legacy liabilities. Canada does not have a long-term disposal site; therefore waste minimization becomes the driving factor behind decontamination for decommissioning before and during dismantlement. This decommissioning job was a great learning experience for decommissioning and the associated contractors who worked on this project. Throughout the life of the project there was a constant focus on waste minimization. This focus was constantly in conflict with regulatory compliance primarily with respect to fire regulations and protecting the facility along with adjacent facilities during the decommissioning activities. Discrepancies in historical documents forced the project to treat every space as a contaminated space until proven differently. Decommissioning and dismantlement within an operating site adds to the complexity of the tasks especially when it is being conducted in the heart of the plant. This project was very successful with no lost time accidents in over one hundred

  2. Spatial analysis of Carbon-14 dynamics in a wetland ecosystem (Duke Swamp, Chalk River Laboratories, Canada).

    PubMed

    Yankovich, T L; King-Sharp, K J; Carr, J; Robertson, E; Killey, R W D; Beresford, N A; Wood, M D

    2014-11-01

    A detailed survey was conducted to quantify the spatial distribution of (14)C in Sphagnum moss and underlying soil collected in Duke Swamp. This wetland environment receives (14)C via groundwater pathways from a historic radioactive Waste Management Area (WMA) on Atomic Energy Canada Limited (AECL)'s Chalk River Laboratories (CRL) site. Trends in (14)C specific activities were evaluated with distance from the sampling location with the maximum (14)C specific activity (DSS-35), which was situated adjacent to the WMA and close to an area of groundwater discharge. Based on a spatial evaluation of the data, an east-to-west (14)C gradient was found, due to the influence of the WMA on (14)C specific activities in the swamp. In addition, it was possible to identify two groups of sites, each showing significant exponential declines with distance from the groundwater source area. One of the groups showed relatively more elevated (14)C specific activities at a given distance from source, likely due to their proximity to the WMA, the location of the sub-surface plume originating from the WMA, the presence of marsh and swamp habitat types, which facilitated (14)C transport to the atmosphere, and possibly, (14)C air dispersion patterns along the eastern edge of the swamp. The other group, which had lower (14)C specific activities at a given distance from the groundwater source area, included locations that were more distant from the WMA and the sub-surface plume, and contained fen habitat, which is known to act as barrier to groundwater flow. The findings suggest that proximity to source, groundwater flow patterns and habitat physical characteristics can play an important role in the dynamics of (14)C being carried by discharging groundwater into terrestrial and wetland environments.

  3. Widespread methanotrophic primary production in lowland chalk rivers.

    PubMed

    Shelley, Felicity; Grey, Jonathan; Trimmer, Mark

    2014-05-22

    Methane is oversaturated relative to the atmosphere in many rivers, yet its cycling and fate is poorly understood. While photosynthesis is the dominant source of autotrophic carbon to rivers, chemosynthesis and particularly methane oxidation could provide alternative sources of primary production where the riverbed is heavily shaded or at depth beneath the sediment surface. Here, we highlight geographically widespread methanotrophic carbon fixation within the gravel riverbeds of over 30 chalk rivers. In 15 of these, the potential for methane oxidation (methanotrophy) was also compared with photosynthesis. In addition, we performed detailed concurrent measurements of photosynthesis and methanotrophy in one large chalk river over a complete annual cycle, where we found methanotrophy to be active to at least 15 cm into the riverbed and to be strongly substrate limited. The seasonal trend in methanotrophic activity reflected that of the riverine methane concentrations, and thus the highest rates were measured in mid-summer. At the sediment surface, photosynthesis was limited by light for most of the year with heavy shading induced by dense beds of aquatic macrophytes. Across 15 rivers, in late summer, we conservatively calculated that net methanotrophy was equivalent to between 1% and 46% of benthic net photosynthetic production within the gravel riverbed, with a median value of 4%. Hence, riverbed chemosynthesis, coupled to the oxidation of methane, is widespread and significant in English chalk rivers.

  4. Development of Molten Corium Using An Exothermic Chemical Reaction for the Molten- Fuel Moderator-Interaction Studies at Chalk River Laboratories

    SciTech Connect

    Nitheanandan, T.; Sanderson, D.B.; Kyle, G.; Farmer, M.

    2004-07-01

    Atomic Energy of Canada Limited (AECL) has partnered with Argonne National Laboratory to develop a corium thermite prototypical of Candu material and test the concept of ejecting {approx}25 kg of the molten material from a pressure tube with a driving pressure of 10 MPa. This development program has been completed and the technology transferred to AECL. Preparation for the molten-fuel moderator-interaction tests at AECL's Chalk River Laboratories is well underway. A mixture of 0.582 U/0.077 U{sub 3}O{sub 8}/0.151 Zr/0.19 CrO{sub 3} (wt%) as reactant chemicals has been demonstrated to produce a corium consisting of 0.73 UO{sub 2}/0.11 Zr/0.06 ZrO{sub 2}/0.10 Cr (wt%) at {approx}2400 deg. C. This is comparable to the target Candu specific corium of 0.9 UO{sub 2}/0.1 Zr (wt%), with limited oxidation. The peak melt temperature was confirmed from small-scale thermitic reaction tests. Several small-scale tests were completed to qualify the thermite to ensure operational safety and a quantifiable experimental outcome. The proposed molten-fuel moderator-interaction experiments at Chalk River Laboratories will consist of heating the thermite mixture inside a 1.14-m long insulated pressure tube. Once the molten material has reached the desired temperature of {approx}2400 deg. C, the pressure inside the tube will be raised to about 10 MPa, and the pressure tube will fail at a pre-machined flaw, ejecting the molten material into the surrounding tank of water. The test apparatus, instrumentation, data acquisition and control systems have been assembled, and a series of successful commissioning tests have been completed. (authors)

  5. Fifty years of accelerator based physics at Chalk River

    SciTech Connect

    McKay, John W.

    1999-04-26

    The Chalk River Laboratories of Atomic Energy of Canada Ltd. was a major centre for Accelerator based physics for the last fifty years. As early as 1946, nuclear structure studies were started on Cockroft-Walton accelerators. A series of accelerators followed, including the world's first Tandem, and the MP Tandem, Superconducting Cyclotron (TASCC) facility that was opened in 1986. The nuclear physics program was shut down in 1996. This paper will describe some of the highlights of the accelerators and the research of the laboratory.

  6. Development of an Integrated Waste Plan for Chalk River Laboratories - 13376

    SciTech Connect

    Jones, L.

    2013-07-01

    To further its Strategic Planning, the Atomic Energy of Canada Limited (AECL) required an effective approach to developing a fully integrated waste plan for its Chalk River Laboratories (CRL) site. Production of the first Integrated Waste Plan (IWP) for Chalk River was a substantial task involving representatives from each of the major internal stakeholders. Since then, a second revision has been produced and a third is underway. The IWP remains an Interim IWP until all gaps have been resolved and all pathways are at an acceptable level of detail. Full completion will involve a number of iterations, typically annually for up to six years. The end result of completing this process is a comprehensive document and supporting information that includes: - An Integrated Waste Plan document summarizing the entire waste management picture in one place; - Details of all the wastes required to be managed, including volume and timings by waste stream; - Detailed waste stream pathway maps for the whole life-cycle for each waste stream to be managed from pre-generation planning through to final disposition; and - Critical decision points, i.e. decisions that need to be made and timings by when they need to be made. A waste inventory has been constructed that serves as the master reference inventory of all waste that has been or is committed to be managed at CRL. In the past, only the waste that is in storage has been effectively captured, and future predictions of wastes requiring to be managed were not available in one place. The IWP has also provided a detailed baseline plan at the current level of refinement. Waste flow maps for all identified waste streams, for the full waste life cycle complete to disposition have been constructed. The maps identify areas requiring further development, and show the complexities and inter-relationships between waste streams. Knowledge of these inter-dependencies is necessary in order to perform effective options studies for enabling

  7. DEMONSTRATION SOLIDIFICATION TESTS CONDUCTED ON RADIOACTIVELY CONTAMINATED ORGANIC LIQUIDS AT THE AECL WHITESHELL LABORATORIES

    SciTech Connect

    Ryz, R. A.; Brunkow, W. G.; Govers, R.; Campbell, D.; Krause, D.

    2002-02-25

    The AECL, Whiteshell Laboratory (WL) near Pinawa Manitoba, Canada, was established in the early 1960's to carry out AECL research and development activities for higher temperature versions of the CANDU{reg_sign} reactor. The initial focus of the research program was the Whiteshell Reactor-1 (WR-1) Organic Cooled Reactor (OCR) that began operation in 1965. The OCR program was discontinued in the early 1970's in favor of the successful heavy-water-cooled CANDU system. WR-1 continued to operate until 1985 in support of AECL nuclear research programs. A consequence of the Federal government's recent program review process was AECL's business decision to discontinue research programs and operations at the Whiteshell Laboratories and to consolidate its' activities at the Chalk River Laboratories. As a result, AECL received government concurrence in 1998 to proceed to plan actions to achieve closure of WL. The planning actions now in progress address the need to safely and effectively transition the WL site from an operational state, in support of AECL's business, to a shutdown and decommissioned state that meets the regulatory requirements for a licensed nuclear site. The decommissioning program that will be required at WL is unique within AECL and Canada since it will need to address the entire research site rather than individual facilities declared redundant. Accordingly, the site nuclear facilities are being systematically placed in a safe shutdown state and planning for the decommissioning work to place the facilities in a secure monitoring and surveillance state is in progress. One aspect of the shutdown activities is to deal with the legacy of radioactively contaminated organic liquid wastes. Use of a polymer powder to solidify these organic wastes was identified as one possibility for improved interim storage of this material pending final disposition.

  8. Isotope hydrology of the Chalk River Laboratories site, Ontario, Canada

    USGS Publications Warehouse

    Peterman, Zell; Neymark, Leonid; King-Sharp, K.J.; Gascoyne, Mel

    2016-01-01

    This paper presents results of hydrochemical and isotopic analyses of groundwater (fracture water) and porewater, and physical property and water content measurements of bedrock core at the Chalk River Laboratories (CRL) site in Ontario. Density and water contents were determined and water-loss porosity values were calculated for core samples. Average and standard deviations of density and water-loss porosity of 50 core samples from four boreholes are 2.73 ± 12 g/cc and 1.32 ± 1.24 percent. Respective median values are 2.68 and 0.83 indicating a positive skewness in the distributions. Groundwater samples from four deep boreholes were analyzed for strontium (87Sr/86Sr) and uranium (234U/238U) isotope ratios. Oxygen and hydrogen isotope analyses and selected solute concentrations determined by CRL are included for comparison. Groundwater from borehole CRG-1 in a zone between approximately +60 and −240 m elevation is relatively depleted in δ18O and δ2H perhaps reflecting a slug of water recharged during colder climatic conditions. Porewater was extracted from core samples by centrifugation and analyzed for major dissolved ions and for strontium and uranium isotopes. On average, the extracted water contains 15 times larger concentration of solutes than the groundwater. 234U/238U and correlation of 87Sr/86Sr with Rb/Sr values indicate that the porewater may be substantially older than the groundwater. Results of this study show that the Precambrian gneisses at Chalk River are similar in physical properties and hydrochemical aspects to crystalline rocks being considered for the construction of nuclear waste repositories in other regions.

  9. Progress in radiocarbon dating with the Chalk River MP tandem accelerator

    SciTech Connect

    Andrews, H.R.; Ball, G.C.; Brown, R.M.; Davies, W.G.; Imahori, Y.; Milton, J.C.D.

    1980-01-01

    The evolution of a tandem accelerator /sup 14/C dating system at Chalk River is recounted. Background problems and sources of instability are discussed and solutions are described. Details of sample chemistry and source preparation are presented.

  10. Management of Legacy Spent Nuclear Fuel Wastes at the Chalk River Laboratories: The Challenges and Innovative Solutions Implemented - 13301

    SciTech Connect

    Schruder, Kristan; Goodwin, Derek

    2013-07-01

    AECL's Fuel Packaging and Storage (FPS) Project was initiated in 2004 to retrieve, transfer, and stabilize an identified inventory of degraded research reactor fuel that had been emplaced within in-ground 'Tile Hole' structures in Chalk River Laboratories' Waste Management Area in the 1950's and 60's. Ongoing monitoring of the legacy fuel storage conditions had identified that moisture present in the storage structures had contributed to corrosion of both the fuel and the storage containers. This prompted the initiation of the FPS Project which has as its objective to design, construct, and commission equipment and systems that would allow for the ongoing safe storage of this fuel until a final long-term management, or disposition, pathway was available. The FPS Project provides systems and technologies to retrieve and transfer the fuel from the Waste Management Area to a new facility that will repackage, dry, safely store and monitor the fuel for a period of 50 years. All equipment and the new storage facility are designed and constructed to meet the requirements for Class 1 Nuclear Facilities in Canada. (authors)

  11. Contaminated groundwater characterization at the Chalk River Laboratories, Ontario, Canada

    SciTech Connect

    Schilk, A.J.; Robertson, D.E.; Thomas, C.W.; Lepel, E.A.; Champ, D.R.; Killey, R.W.D.; Young, J.L.; Cooper, E.L.

    1993-03-01

    The licensing requirements for the disposal of low-level radioactive waste (10 CFR 61) specify the performance objectives and technical requisites for federal and commercial land disposal facilities, the ultimate goal of which is to contain the buried wastes so that the general population is adequately protected from harmful exposure to any released radioactive materials. A major concern in the operation of existing and projected waste disposal sites is subterranean radionuclide transport by saturated or unsaturated flow, which could lead to the contamination of groundwater systems as well as uptake by the surrounding biosphere, thereby directly exposing the general public to such materials. Radionuclide transport in groundwater has been observed at numerous commercial and federal waste disposal sites [including several locations within the waste management area of Chalk River Laboratories (CRL)], yet the physico-chemical processes that lead to such migration are still not completely understood. In an attempt to assist in the characterization of these processes, an intensive study was initiated at CRL to identify and quantify the mobile radionuclide species originating from three separate disposal sites: (a) the Chemical Pit, which has received aqueous wastes containing various radioisotopes, acids, alkalis, complexing agents and salts since 1956, (b) the Reactor Pit, which has received low-level aqueous wastes from a reactor rod storage bay since 1956, and (c) the Waste Management Area C, a thirty-year-old series of trenches that contains contaminated solid wastes from CRL and various regional medical facilities. Water samples were drawn downgradient from each of the above sites and passed through a series of filters and ion-exchange resins to retain any particulate and dissolved or colloidal radionuclide species, which were subsequently identified and quantified via radiochemical separations and gamma spectroscopy. These groundwaters were also analyzed for anions

  12. Risk-based Prioritization of Facility Decommissioning and Environmental Restoration Projects in the National Nuclear Legacy Liabilities Program at the Chalk River Laboratory - 13564

    SciTech Connect

    Nelson, Jerel G.; Kruzic, Michael; Castillo, Carlos; Pavey, Todd; Alexan, Tamer; Bainbridge, Ian

    2013-07-01

    Chalk River Laboratory (CRL), located in Ontario Canada, has a large number of remediation projects currently in the Nuclear Legacy Liabilities Program (NLLP), including hundreds of facility decommissioning projects and over one hundred environmental remediation projects, all to be executed over the next 70 years. Atomic Energy of Canada Limited (AECL) utilized WorleyParsons to prioritize the NLLP projects at the CRL through a risk-based prioritization and ranking process, using the WorleyParsons Sequencing Unit Prioritization and Estimating Risk Model (SUPERmodel). The prioritization project made use of the SUPERmodel which has been previously used for other large-scale site prioritization and sequencing of facilities at nuclear laboratories in the United States. The process included development and vetting of risk parameter matrices as well as confirmation/validation of project risks. Detailed sensitivity studies were also conducted to understand the impacts that risk parameter weighting and scoring had on prioritization. The repeatable prioritization process yielded an objective, risk-based and technically defendable process for prioritization that gained concurrence from all stakeholders, including Natural Resources Canada (NRCan) who is responsible for the oversight of the NLLP. (authors)

  13. Response of invertebrates from the hyporheic zone of chalk rivers to eutrophication and land use.

    PubMed

    Pacioglu, Octavian; Moldovan, Oana Teodora

    2016-03-01

    Whereas the response of lotic benthic macroinvertebrates to different environmental stressors is a widespread practice nowadays in assessing the water and habitat quality, the use of hyporheic zone invertebrates is still in its infancy. In this study, classification and regression trees analysis were employed in order to assess the ecological requirements and the potential as bioindicators for the hyporheic zone invertebrates inhabiting four lowland chalk rivers (south England) with contrasting eutrophication levels (based on surface nitrate concentrations) and magnitude of land use (based on percentage of fine sediments load and median interstitial space). Samples of fauna, water and sediment were sampled twice, during low (summer) and high (winter) groundwater level, at depths of 20 and 35 cm. Certain groups of invertebrates (Glossosomatidae and Psychomyiidae caddisflies, and riffle beetles) proved to be good indicators of rural catchments, moderately eutrophic and with high fine sediment load. A diverse community dominated by microcrustaceans (copepods and ostracods) were found as good indicators of highly eutrophic urban streams, with moderate-high fine sediment load. However, the use of other taxonomic groups (e.g. chironomids, oligochaetes, nematodes, water mites and the amphipod Gammarus pulex), very widespread in the hyporheic zone of all sampled rivers, is of limited use because of their high tolerance to the analysed stressors. We recommend the use of certain taxonomic groups (comprising both meiofauna and macroinvertebrates) dwelling in the chalk hyporheic zone as indicators of eutrophication and colmation and, along with routine benthic sampling protocols, for a more comprehensive water and habitat quality assessment of chalk rivers.

  14. Brockhouse and others: Neutron Scattering and Condensed Matter Physics at Chalk River Labs

    NASA Astrophysics Data System (ADS)

    Svensson, Eric

    2004-03-01

    Bertram Brockhouse, in brilliant, pioneering work carried out during the period 1950-1962 at Chalk River Laboratories, laid the foundation for the field of inelastic neutron scattering. Bert invented/developed an abundance of new instrumentation (most notably the Triple Axis Crystal Spectrometer) and techniques (most notably the Constant-Q Method) and he and his collaborators carried out a truly impressive number of ground breaking measurements. These included the first determination of phonon dispersion curves (in aluminum in 1955, with Alec Stewart), the first determination of a magnon dispersion curve (in magnetite in 1958), the first measurements of phonons in semiconductors, alkali halides and several other metals, the first measurements of magnons in a metal (cobalt), and the first observation of a Kohn anomaly. Bert Brockhouse was a great scientist with an amazing intuition, but, as he regularly emphasized, the terrific atmosphere for scientific research at Chalk River Labs as well as the outstanding technical support staff and facilities were essential ingredients of his success. He also had unlimited access to, in succession, the NRX and NRU reactors which were, when they were commissioned (in 1947 and 1957) and for several years thereafter, the best research reactors in the world. Bert's accomplishments were ultimately recognized by the 1994 Nobel Prize in Physics, which he shared with Clifford Shull of the United States, Cliff having laid the foundation for the field of elastic neutron scattering. My presentation will focus strongly on the work of Brockhouse, but I will also cover several highlights from the Chalk River program of neutron scattering studies on liquid helium, started in 1952 by Dave Henshaw and Don Hurst. (Don Hurst was the person who hired Bert Brockhouse and charged him with "finding something interesting to do with neutrons".) The helium program, now running almost continuously for half a century, has been a major focus of my own

  15. Overview of the 1994 chronic HT release experiment at Chalk River

    SciTech Connect

    Davis, P.A.; Workman, W.J.G.; Amiro, B.D.; Spencer, F.S.; Noguchi, H.; Amano, H.; Ichimasa, Y.; Ichimasa, M.

    1995-10-01

    Trace amounts of tritiated hydrogen (HT) were released continuously to the atmosphere at Chalk River Laboratories over the 12-day period 1994 July 27 to August 8. Scientists from eight institutions in four countries took extensive air, soil and vegetation samples to study the dynamics of tritiated water (HTO) and organically-bound tritium (OBT) formation, and the environmental concentrations of these compounds at steady-state. The short-term HT air concentrations varied strongly in time and space over the test area, but the variation decreased rapidly as the averaging time increased. HTO concentrations in soil, vegetation and air built up gradually over time but they fluctuated substantially with ambient meteorological conditions, particularly rainfall. OBT concentrations in plants increased throughout the period. HTO concentrations were at or near steady-state at the end of the release, but OBT levels were continuing to rise. 8 refs., 2 figs., 1 tab.

  16. Transport of three herbicides in ground water at Twin Lake test site, Chalk River, Ontario, Canada.

    PubMed

    Maloszewski, P; Zuber, A; Bedbur, E; Matthess, G

    2003-01-01

    A field tracer test performed under natural flow conditions at the Twin Lake test site, Chalk River Laboratories of the Atomic Energy of Canada Ltd. in Chalk River, Ontario, Canada, using tritium and three herbicides (Chlortoluron, Terbuthylazine, and Pendimethalin) was interpreted using the dispersion equation with a combined reaction model. The reaction model couples an instantaneous equilibrium reaction governed by a linear adsorption isotherm with a reversible or irreversible kinetic reaction of the first order, and decay. An improved interpretation method consists of a simultaneous fitting of theoretical concentration and mass-recovery curves to the experimental data, which leads to a more reliable determining of reaction models and improves the accuracy of fitting. Tritium served as the reference tracer to determine the flow velocity, dispersivity, and the recovery of the herbicides. Chlortoluron was slightly delayed by equilibrium exchange with strongly reduced concentration due to an irreversible kinetic reaction and/or decay. Terbuthilazine was slightly delayed by equilibrium exchange, with strongly reduced concentration due to a reversible kinetic reaction with some influence of decay. A strong equilibrium reaction and a strong reversible kinetic reaction without degradation governed the transport of Pendimethalin, reducing considerably its concentration. The results obtained show that simulations based only on Kd and decay constant, especially if these parameters are found in the laboratory, may considerably differ from those performed with reaction parameters determined in properly performed field tests. The dominant reaction types, and the values of parameters found in the study, supply useful information on the transport of the investigated herbicides in sandy aquifers under natural flow conditions.

  17. Simulating Heterogeneous Infiltration and Contaminant leaching Processes at Chalk River, Ontario

    NASA Astrophysics Data System (ADS)

    Ali, M. A.; Ireson, A. M.; Keim, D.

    2015-12-01

    A study is conducted at a waste management area in Chalk River, Ontario to characterize flow and contaminant transport with the aim of contributing to improved hydrogeological risk assessment in the context of waste management. Field monitoring has been performed to gain insights into the unsaturated zone characteristics, moisture dynamics, and contaminant transport rates. The objective is to provide quantitative estimates of surface fluxes (quantification of infiltration and evaporation) and investigations of unsaturated zone processes controlling water infiltration and spatial variability in head distributions and flow rates. One particular issue is to examine the effectiveness of the clayey soil cap installed to prevent infiltration of water into the waste repository and the top sand soil cover above the clayey layer to divert the infiltrated water laterally. The spatial variability in the unsaturated zone properties and associated effects on water flow and contaminant transport observed at the site, have led to a concerted effort to develop improved model of flow and transport based on stochastic concepts. Results obtained through the unsaturated zone model investigations are combined with the hydrogeological and geochemical components and develop predictive tools to assess the long term fate of the contaminants at the waste management site.

  18. The implications of using large ensembles of climate scenarios for the management of river ecology in an English chalk stream

    NASA Astrophysics Data System (ADS)

    Fung, C. F.; Lopez, A.; New, M.

    2009-04-01

    Climate change is likely to impact on freshwater ecology, the delivery of regulatory commitments to ecological status and the management of water resources. It is becoming increasingly important for European environment agencies to use and develop methods to aid planning and abstraction licensing procedures and policies in the face of climate change and with the introduction of the Water Framework Directive. Studies have been carried out in the past to investigate the implications of climate change for biodiversity. However, predicting the future is fraught with uncertainty, an area which has not been dealt with in great depth in the past. This study has been undertaken to draw on the results of new methodologies to address the uncertainties inherent in modelling future climate and assess their usability for decision-making in water resources allocations specifically in considering interactions between flow and invertebrate communities The River Itchen was chosen as the case study catchment on the strength of having a long-term coupled ecological and flow dataset and having been an area of intensive study in the past. It is a chalk stream located in the south of England and a candidate Special Area of Conservation. It has also been designated a Special Site of Scientific Interest achieved due to the number of rare species, and the richness of the macro-invertebrate community in the river catchment. An ensemble of 246 transient simulations for future climate was obtained from ClimatePrediction.net which were then used to drive a rainfall-runoff model. In order to link the modelled river flow to ecology, the Lotic Invertebrate Flow Evaluation score has been used where the invertebrate community is linked to flow largely through sensitivity to water velocity and siltation, driven by flow variability at sites with fixed channel dimensions The large ensemble of climate scenarios and thereby flow and ecological indices allows the exploration of the risk of the river of

  19. Controlled drill & blast excavation at AECL`s Underground Research Laboratory

    SciTech Connect

    Kuzyk, G.W.; Onagi, D.P.; Thompson, P.M.

    1996-12-01

    A controlled drill and blast method has been developed and used to excavate the Underground Research Laboratory, a geotechnical facility constructed by Atomic Energy of Canada Limited (AECL) in crystalline rock. It has been demonstrated that the method can effectively reduce the excavation disturbed zone (EDZ) and is suitable for the construction of a used fuel disposal vault in the plutonic rock of the Canadian Shield.

  20. Dealing with Historical Discrepancies: The Recovery of National Research Experiment (NRX) Reactor Fuel Rods at Chalk River Laboratories (CRL) - 13324

    SciTech Connect

    Vickerd, Meggan

    2013-07-01

    Following the 1952 National Research Experiment (NRX) Reactor accident, fuel rods which had short irradiation histories were 'temporarily' buried in wooden boxes at the 'disposal grounds' during the cleanup effort. The Nuclear Legacy Liabilities Program (NLLP), funded by Natural Resources Canada (NRCan), strategically retrieves legacy waste and restores lands affected by Atomic Energy of Canada Limited (AECL) early operations. Thus under this program the recovery of still buried NRX reactor fuel rods and their relocation to modern fuel storage was identified as a priority. A suspect inventory of NRX fuels was compiled from historical records and various research activities. Site characterization in 2005 verified the physical location of the fuel rods and determined the wooden boxes they were buried in had degraded such that the fuel rods were in direct contact with the soil. The fuel rods were recovered and transferred to a modern fuel storage facility in 2007. Recovered identification tags and measured radiation fields were used to identify the inventory of these fuels. During the retrieval activity, a discrepancy was discovered between the anticipated number of fuel rods and the number found during the retrieval. A total of 32 fuel rods and cans of cut end pieces were recovered from the specified site, which was greater than the anticipated 19 fuel rods and cans. This discovery delayed the completion of the project, increased the associated costs, and required more than anticipated storage space in the modern fuel storage facility. A number of lessons learned were identified following completion of this project, the most significant of which was the potential for discrepancies within the historical records. Historical discrepancies are more likely to be resolved by comprehensive historical record searches and site characterizations. It was also recommended that a complete review of the wastes generated, and the total affected lands as a result of this historic

  1. The Results From the First High-Pressure Melt Ejection Test Completed in the Molten Fuel Moderator Interaction Facility at Chalk River Laboratories

    SciTech Connect

    Nitheanandan, T.; Kyle, G.; O'Connor, R.; Sanderson, DB.

    2006-07-01

    A high-pressure melt ejection test using prototypical corium was conducted at Atomic Energy of Canada Limited Chalk River Laboratories. This test was planned by the CANDU Owners Group to study the potential for an energetic interaction between molten fuel and water under postulated single-channel flow-blockage events. The experiments were designed to address regulator concerns surrounding this very low probability postulated accident events in CANDU Pressurized Heavy Water Reactors. The objective of the experimental program is to determine whether a highly energetic 'steam explosion' and associated high-pressure pulse, is possible when molten material is finely fragmented as it is ejected from a fuel channel into the heavy-water moderator. The finely fragmented melt particles would transfer energy to the moderator as it is dispersed, creating a modest pressure pulse in the calandria vessel. The high-pressure melt ejection test consisted of heating up a {approx} 5 kg thermite mixture of U, U{sub 3}O{sub 8}, Zr, and CrO{sub 3} inside a 1.14-m length of insulated pressure tube. When the molten material reached the desired temperature of {approx} 2400 deg C, the pressure inside the tube was raised to 11.6 MPa, failing the pressure tube at a pre-machined flaw, and releasing the molten material into the surrounding tank of 68 deg C water. The experiment investigated the dynamic pressure history, debris size, and the effects of the material interacting with tubes representing neighbouring fuel channels. The measured mean particle size was 0.686 mm and the peak dynamic pressures were between 2.54 and 4.36 MPa, indicating that an energetic interaction between the melt and the water did not occur in the test. (authors)

  2. Macrophyte and periphyton dynamics in a UK Cretaceous Chalk stream: the river Kennet, a tributary of the Thames.

    PubMed

    Flyn, N J; Snook, D L; Wade, A J; Jarvie, H P

    2002-01-23

    An initial study to observe the seasonal trends and to determine the factors influencing macrophyte and periphyton growth patterns was undertaken on a representative reach of the River Kennet (UK) over a 2-year period (1998-2000). Maximum average macrophyte and average periphyton dry matter biomass recorded during the growing season were 200 and 21 g m(-2), respectively. The relationships between macrophyte and periphyton percentage cover and biomass data with physico-chemical variables were investigated. Regression analysis indicated that of the parameters measured, flow, and in the case of the dominant Ranunculus spp., solar radiation, were best able to predict macrophyte biomass and cover. The periphytic biomass within the reach was low, possibly as a result of relatively high flows and low phosphorus concentrations following the introduction of effluent treatment at the sewage works immediately upstream of the reach. Periphytic biomass was poorly correlated with the physical variables measured. This indicates that biomass is regulated by complex interactions between the physical and chemical factors, such as flow, solar radiation and phosphorus concentration. These interrelationships require further investigation.

  3. An Investigation into the Transportation of Irradiated Uranium/Aluminum Targets from a Foreign Nuclear Reactor to the Chalk River Laboratories Site in Ontario, Canada - 12249

    SciTech Connect

    Clough, Malcolm; Jackson, Austin

    2012-07-01

    This investigation required the selection of a suitable cask and development of a device to hold and transport irradiated targets from a foreign nuclear reactor to the Chalk River Laboratories in Ontario, Canada. The main challenge was to design and validate a target holder to protect the irradiated HEU-Al target pencils during transit. Each of the targets was estimated to have an initial decay heat of 118 W prior to transit. As the targets have little thermal mass the potential for high temperature damage and possibly melting was high. Thus, the primary design objective was to conceive a target holder to dissipate heat from the targets. Other design requirements included securing the targets during transportation and providing a simple means to load and unload the targets while submerged five metres under water. A unique target holder (patent pending) was designed and manufactured together with special purpose experimental apparatus including a representative cask. Aluminum dummy targets were fabricated to accept cartridge heaters, to simulate decay heat. Thermocouples were used to measure the temperature of the test targets and selected areas within the target holder and test cask. After obtaining test results, calculations were performed to compensate for differences between experimental and real life conditions. Taking compensation into consideration the maximum target temperature reached was 231 deg. C which was below the designated maximum of 250 deg. C. The design of the aluminum target holder also allowed generous clearance to insert and unload the targets. This clearance was designed to close up as the target holder is placed into the cavity of the transport cask. Springs served to retain and restrain the targets from movement during transportation as well as to facilitate conductive heat transfer. The target holder met the design requirements and as such provided data supporting the feasibility of transporting targets over a relatively long period of time

  4. Chalk Murals and Great Artists.

    ERIC Educational Resources Information Center

    Schweizer, Kay

    2000-01-01

    Discusses the Annual Chalk Mural project done by the members of the National Art Honor Society at the Sacramento County Day School. Discusses the tradition of the annual project and the planning and research involved. Focuses on the 7th Annual Chalk Mural featuring Wayne Thiebaud. (CMK)

  5. PAH occurrence in chalk river systems from the Jura region (France). Pertinence of suspended particulate matter and sediment as matrices for river quality monitoring.

    PubMed

    Chiffre, Axelle; Degiorgi, François; Morin-Crini, Nadia; Bolard, Audrey; Chanez, Etienne; Badot, Pierre-Marie

    2015-11-01

    This study investigates the variations of polycyclic aromatic hydrocarbon (PAH) levels in surface water, suspended particulate matter (SPM) and sediment upstream and downstream of the discharges of two wastewater treatment plant (WWTP) effluents. Relationships between the levels of PAHs in these different matrices were also investigated. The sum of 16 US EPA PAHs ranged from 73.5 to 728.0 ng L(-1) in surface water and from 85.4 to 313.1 ng L(-1) in effluent. In SPM and sediment, ∑16PAHs ranged from 749.6 to 2,463 μg kg(-1) and from 690.7 μg kg(-1) to 3,625.6 μg kg(-1), respectively. Investigations performed upstream and downstream of both studied WWTPs showed that WWTP discharges may contribute to the overall PAH contaminations in the Loue and the Doubs rivers. Comparison between gammarid populations upstream and downstream of WWTP discharge showed that biota was impacted by the WWTP effluents. When based only on surface water samples, the assessment of freshwater quality did not provide evidence for a marked PAH contamination in either of the rivers studied. However, using SPM and sediment samples, we found PAH contents exceeding sediment quality guidelines. We conclude that sediment and SPM are relevant matrices to assess overall PAH contamination in aquatic ecosystems. Furthermore, we found a positive linear correlation between PAH contents of SPM and sediment, showing that SPM represents an integrating matrix which is able to provide meaningful data about the overall contamination over a given time span.

  6. Less chalk more action

    NASA Astrophysics Data System (ADS)

    Mitriceski Andelkovic, Bojana; Jovic, Sladjana

    2016-04-01

    Less chalk more action Education should not be a mechanical system that operates according to the principles of the orders and implementation. Education should respect the basic laws of the develop and progress. Curiosity is the engine of achievement and children spontaneously and happily learn only if they get interested, if teacher wake up and stimulate their creativity and individuality. We would like to present classes that are realized as thematic teaching with several subjects involved: chemistry, geography, math, art and biology. Classes were organized for students at age from 10 to 13 years, every month during autumn and winter 2015. Better students identified themselves as teachers and presented peer education .Teachers were monitoring the process of teaching and help to develop links between younger and older students, where older students were educators to younger students. Also one student with special needs was involved in this activities and was supported by other students during the workshops The benefit from this project will be represented with evaluation marks. Evaluation table shows that group of ten students(age 10 to13 years) which are selected in October as children with lack of motivation for learning, got better marks, at the end of January , then they had it in the beginning of the semester.

  7. ChalkBoard: Mapping Functions to Polygons

    NASA Astrophysics Data System (ADS)

    Matlage, Kevin; Gill, Andy

    ChalkBoard is a domain specific language for describing images. The ChalkBoard language is uncompromisingly functional and encourages the use of modern functional idioms. ChalkBoard uses off-the-shelf graphics cards to speed up rendering of functional descriptions. In this paper, we describe the design of the core ChalkBoard language, and the architecture of our static image generation accelerator.

  8. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Chalk Hill. 9.52 Section 9... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  9. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Chalk Hill. 9.52 Section 9... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  10. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Chalk Hill. 9.52 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  11. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Chalk Hill. 9.52 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  12. Sewage effluent clean-up reduces phosphorus but not phytoplankton in lowland chalk stream (River Kennet, UK) impacted by water mixing from adjacent canal.

    PubMed

    Neal, Colin; Martin, Ellie; Neal, Margaret; Hallett, John; Wickham, Heather D; Harman, Sarah A; Armstrong, Linda K; Bowes, Mike J; Wade, Andrew J; Keay, David

    2010-10-15

    Information is provided on phosphorus in the River Kennet and the adjacent Kennet and Avon Canal in southern England to assess their interactions and the changes following phosphorus reductions in sewage treatment work (STW) effluent inputs. A step reduction in soluble reactive phosphorus (SRP) concentration within the effluent (5 to 13 fold) was observed from several STWs discharging to the river in the mid-2000s. This translated to over halving of SRP concentrations within the lower Kennet. Lower Kennet SRP concentrations change from being highest under base-flow to highest under storm-flow conditions. This represented a major shift from direct effluent inputs to a within-catchment source dominated system characteristic of the upper part to the catchment. Average SRP concentrations in the lower Kennet reduced over time towards the target for good water quality. Critically, there was no corresponding reduction in chlorophyll-a concentration, the waters remaining eutrophic when set against standards for lakes. Following the up gradient input of the main water and SRP source (Wilton Water), SRP concentrations in the canal reduced down gradient to below detection limits at times near its junction with the Kennet downstream. However, chlorophyll concentrations in the canal were in an order of magnitude higher than in the river. This probably resulted from long water residence times and higher temperatures promoting progressive algal and suspended sediment generations that consumed SRP. The canal acted as a point source for sediment, algae and total phosphorus to the river especially during the summer months when boat traffic disturbed the canal's bottom sediments and the locks were being regularly opened. The short-term dynamics of this transfer was complex. For the canal and the supply source at Wilton Water, conditions remained hypertrophic when set against standards for lakes even when SRP concentrations were extremely low.

  13. Chalk Line Mill, Anniston, AL

    EPA Pesticide Factsheets

    The Chalk Line Mill property was the site of a textile mill which operated from 1887 until 1994. Demolition activities in 2004 removed most of the structures on-site, but also left large, unsightly piles of debris scattered across this 14-acre property. The City applied for and received a $200,000 Brownfields cleanup grant in 2007 to address contamination on the property and the Appalachian Regional Commission provided an additional $150,000 in funding.

  14. A novel representation of chalk hydrology in a land surface model

    NASA Astrophysics Data System (ADS)

    Rahman, Mostaquimur; Rosolem, Rafael

    2016-04-01

    Unconfined chalk aquifers contain a significant portion of water in the United Kingdom. In order to optimize the assessment and management practices of water resources in the region, modelling and monitoring of soil moisture in the unsaturated zone of the chalk aquifers are of utmost importance. However, efficient simulation of soil moisture in such aquifers is difficult mainly due to the fractured nature of chalk, which creates high-velocity preferential flow paths in the unsaturated zone. In this study, the Joint UK Land Environment Simulator (JULES) is applied on a study area encompassing the Kennet catchment in Southern England. The fluxes and states of the coupled water and energy cycles are simulated for 10 consecutive years (2001-2010). We hypothesize that explicit representation for the soil-chalk layers and the inclusion of preferential flow in the fractured chalk aquifers improves the reproduction of the hydrological processes in JULES. In order to test this hypothesis, we propose a new parametrization for preferential flow in JULES. This parametrization explicitly describes the flow of water in soil matrices and preferential flow paths using a simplified approach which can be beneficial for large-scale hydrometeorological applications. We also define the overlaying soil properties obtained from the Harmonized World Soil Database (HWSD) in the model. Our simulation results are compared across spatial scales with measured soil moisture and river discharge, indicating the importance of accounting for the physical properties of the medium while simulating hydrological processes in the chalk aquifers.

  15. Pointing with Power or Creating with Chalk

    ERIC Educational Resources Information Center

    Rudow, Sasha R.; Finck, Joseph E.

    2015-01-01

    This study examines the attitudes of students on the use of PowerPoint and chalk/white boards in college science lecture classes. Students were asked to complete a survey regarding their experiences with PowerPoint and chalk/white boards in their science classes. Both multiple-choice and short answer questions were used. The multiple-choice…

  16. Cretaceous shelf-sea chalk deposits

    SciTech Connect

    Hattin, D.E.

    1988-01-01

    The word ''chalk'' is linked etymologically to the Cretaceous, but chalky facies neither dominate that system nor are confined to it. As used commonly, the term ''chalk'' refers to a variety of marine limestone that is white to light gray very fine grained, soft and friable, porous, and composed predominantly of calcitic skeletal remains, especially those derived from coccolithophores. No simple definition suffices to embrace all Cretaceous chalks, which include sandy, marly, shelly, phospatic, glauconitic, dolomitic, pyritic and organic-rich lithotypes. Most of the world's exposed Cretaceous chalk deposits were formed at shelf depths rather than in the deep sea. Cretaceous shelf-sea chalks are developed most extensively in northern Europe, the U.S. Gulf Coastal Plain and Western Interior, and the Middle East, with lesser occurrences alo in Australia. Most Cretaceous shelf-sea chalks formed in the temperature zones, and in relatively deep water. Cretaceous chalks deposited on well-oxygenated sea floors are bioturbated and massive where deficient in terrigenous detritus, or bioturbated and rhythmically interbedded with argillaceous units where influx of terrigenous detritus varied systematically with climate changes. Accumulation of sufficient pelagic mud to form vast deposits of Cretaceous shelf-sea chalk required (1) sustained high productivity of calareous plankton, (2) extensive development of stable shelf and continental platform environments, (3) highstands of seal level, (4) deficiency of aragonitic skeletal material in chalk-forming sediments, and (5) low rates of terrigenous detrital influx. These conditions were met at different times in different places, even within the same general region.

  17. Microdeformation and subcritical cracking in chalk

    NASA Astrophysics Data System (ADS)

    Bergsaker, Anne; Dysthe, Dag Kristian

    2016-04-01

    Deformation processes in chalks, both in relation to changing pore fluids and stress conditions has been of great interest as chalk is an important reservoir rock for both hydrocarbons and ground water. Lately it has also gained interest as a potential reservoir rock for captured CO2. Chalks are composed of large amounts of biogenic calcite grains, the skeletal debris of marine microorganisms. Its deformation is highly time and stress dependent, and governed by a transition from distributed to localized deformation at the onset of yield, affected by mechanisms such as subcritical crack growth and pore collapse. We present a microdeformation rig which makes use of thermal expansion as a means of subjecting small samples to strictly controlled tensile stresses. High resolution imaging provides resolutions down to 0.5 micrometers, enabling study of pore scale processes during slow deformation. Examples of localized and distributed deformation are presented.

  18. The End of "Chalk and Talk"

    ERIC Educational Resources Information Center

    Barlow, Tim

    2012-01-01

    "Chalk and talk" had been the staple pedagogical approach of my Science teaching practice since entering the profession. I felt that there was a great deal of information that I must impart to my students. My tried and tested way to deliver information to my students had always been simply to stand in front of them and tell it to them... So what…

  19. Competitive sorption of organic contaminants in chalk

    NASA Astrophysics Data System (ADS)

    Graber, E. R.; Borisover, M.

    2003-12-01

    In the Negev desert, Israel, a chemical industrial complex is located over fractured Eocene chalk formations where transfer of water and solutes between fracture voids and matrix pores affects migration of contaminants in the fractures due to diffusion into the chalk matrix. This study tests sorption and sorption competition between contaminants in the chalk matrix to make it possible to evaluate the potential for contaminant attenuation during transport in fractures. Single solute sorption isotherms on chalk matrix material for five common contaminants ( m-xylene, ametryn, 1,2-dichloroethane, phenanthrene, and 2,4,6-tribromophenol) were found to be nonlinear, as confirmed in plots of Kd versus initial solution concentration. Over the studied concentration ranges, m-xylene Kd varied by more than a factor of 100, ametryn Kd by a factor of 4, 1,2-dichloroethane Kd by more than a factor of 3, phenanthrene Kd by about a factor of 2, and 2,4,6-tribromophenol Kd by a factor of 10. It was earlier found that sorption is to the organic matter component of the chalk matrix and not to the mineral phases (Chemosphere 44 (2001) 1121). Nonlinear sorption isotherms indicate that there is at least some finite sorption domain. Bi-solute competition experiments with 2,4,6-tribromophenol as the competitor were designed to explore the nature of the finite sorption domain. All of the isotherms in the bi-solute experiments are more linear than in the single solute experiments, as confirmed by smaller variations in Kd as a function of initial solution concentration. For both m-xylene and ametryn, there is a small nonlinear component or domain that was apparently not susceptible to competition by 2,4,6-tribromophenol. The nonlinear sorption domain(s) is best expressed at low solution concentrations. Inert-solvent-normalized single and bi-solute sorption isotherms demonstrate that ametryn undergoes specific force interactions with the chalk sorbent. The volume percent of phenanthrene

  20. Giddings Austin chalk enters deep lean-gas phase

    SciTech Connect

    Moritis, G.

    1995-12-25

    Deep lean gas is the latest phase in the growth of the Giddings field Austin chalk play. The first phase involved drilling vertical oil and gas wells. Next came the horizontal well boom in the shallower Austin chalk area, which is still continuing. And now this third phase places horizontal laterals in the Austen chalk at about 14,000--15,000 ft to produce lean gas. The article describes the producing wells and gas gathering.

  1. The Beauty of the Beasts in Chalk Pastels

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2010-01-01

    In this article, the author describes how her seventh-grade art students captured an image of a stuffed animal in the "whole-to-part" drawing technique using chalk pastels. Shading with chalk pastels can give a gradual change in value from dark to light. The shading and color changes the mood of the original drawing, and adds texture, too. Chalk…

  2. Horizontal drilling in the Austin Chalk: Stratigraphic factors

    SciTech Connect

    Durham, C.O. Jr. ); Bobigian, R.A. )

    1990-05-01

    Horizontal drilling has renewed interest in the Austin chalk in south-central Texas. Large fields on opposite sides of the San Marcos arch Giddings to the northeast and Pearsall to the southwest were active with vertical drilling 10 years ago. Giddings' 4,500 Austin wells produced 209 million BO and 934 bcfg of gas through 1988; Pearsall's 1,440 wells produced 57 million BO and 35 bcfg of gas. Most vertical wells were completed, 20% were economic successes, 40% were marginal, 40% were uneconomic due to uneven areal distribution of near-vertical fractures and small faults, which provide reservoirs in otherwise tight chalk. Horizontal drilling, led by Amoco in Giddings and Oryx in Pearsall, enhances the chances of encountering the fractures by drilling perpendicular to the fracture trend. Horizontal drilling requires preselection of the stratigraphic horizon to be penetrated. One must understand the variable Austin stratigraphy to choose the zone with the most brittle character and best matrix porosity, both reduced by increased clay content. Chalk 130 ft thick on the San Marcos arch thickens to 600 to 800 ft in central Giddings field where middle marl separates lower and upper chalk Northeastward only lower chalk is preserved beneath a post-Austin submarine channel. The Austin thickens to 300-500 ft in Pearsall field where middle member ash beds separate lower and upper chalk inhibiting vertical reservoir communication. Locally, on the Pearsall arch, ash is missing, lower chalk thickens, and upper chalk thins.

  3. Austin Chalk (!) Petroleum System: Upper Cretaceous, Southeastern Texas

    SciTech Connect

    Dawson, W.C.; Katz, B.J.; Robison, V.D.

    1995-10-01

    The Austin Group (Coniacian-Santonian) is a sequence of interstratified chalk and marl deposited during a sea-level highstand as a transgressive unit. Austin Chalk deposition occurred on a southeastward-dipping carbonate ramp that exhibits distinctive onshore and offshore chalk lithofacies. Discrete intervals within offshore Austin lithofacies display good to excellent source rock potential. Organic carbon content ranges upward to 20.0 wt. % with generation potentials exceeding 45 mg HC/g of rock measured. Source potential increases basinward where offshore chalk units exhibit increases in both organic richness and net thickness. These organically rich units display an affinity for the Type II reference curve. Hydrogen index values typically exceed 300 mg HC/g TOC. Several geochemical indices suggest that the oil-window is located at relatively shallow depths (6,700 ft). Offshore chalks sourced onshore Austin reservoirs through lateral migration (along fractures and stylolites) which occurred during the middle Tertiary. Hydrocarbons may also have been sourced from the underlying Eagle Ford Shale (Turonian). Austin Shale reservoirs are characterized by low porosity/low permeability dual pore systems consisting of microporous matrix and fractures. Diagenesis (mechanical compaction, styloitization, and calcite cementation) has strongly modified Austin Chalk pore systems. Matrix porosity generally decreases with increasing depth because of progressive burial diagenesis. Austin reservoirs typically have two major sets of fractures; reservoir performance is related to fracture connectivity. Austin Chalk reservoirs are sealed by the overlying Taylor Marl (Campanian).

  4. Chalk dustfall during classroom teaching: particle size distribution and morphological characteristics.

    PubMed

    Majumdar, Deepanjan; William, S P M Prince

    2009-01-01

    The study was undertaken to examine the nature of particulate chalk dust settled on classroom floor during traditional teaching with dusting and non-dusting chalks on two types of boards viz. rough and smooth. Settling chalk particles were collected for 30 min during teaching in glass Petri plates placed in classrooms within 3 m distance from the teaching boards. Particle size distribution, scanning electron microscopic images of chalk dusts and compressive strength of two types of chalks were tested and evaluated. Results showed that a larger proportion of dusts generated from anti-dusting chalks were of <4.5 and <2.5 microm size on both smooth and rough boards, as compared to dusting chalks. Non-dusting chalks, on an average, produced about 56% and 62% (by volume) of <4.5 microm (respirable) diameter, on rough and smooth boards, respectively, while the corresponding values for dusting chalks were 36% and 45%. Also, on an average, 83% and 94% (by volume) of the particles were <11 microm (thoracic) in case of non-dusting chalks against 61% and 72% for dusting chalks on rough and smooth boards, respectively. Interestingly, taking into account the mass of chalk dust produced per unit time, which was higher in dusting chalks than non dusting chalks, the former was actually producing higher amount of PM <4.5 and <11 particles from both types of boards. Scanning electron microscope images revealed that chalk particles had random shape, although in dusting chalks prevalence of elongated particles was observed, apparently due to the longitudinal breaking of the chalks during writing, which was confirmed during compressive strength testing. We could conclude that dusting chalks could be potentially more harmful than anti dusting chalks, as they produced higher amount of potentially dangerous PM 4.5 and PM 11.

  5. Evidence of influence of regional and local heterogeneities within a chalk karst aquifer based on nitrates and chlorides analysis

    NASA Astrophysics Data System (ADS)

    El Janyani, S.; Dupont, J. P.; Massei, N.; Dörfliger, N.

    2012-04-01

    In Upper Normandy, a region located in the western Paris Basin, the main source of drinking water comes from the karst aquifer. Developing under the chalk plateaus, it is a covered aquifer overlaid by superficial formations of clay-with-flints and loess. Clay-with-flints result from chalk weathering whereas loess are wind periglacial deposits. The local geologic and hydrogelogic contexts are characterized by a mature development of sinkholes. The chalk karst is causing turbidity, often linked to the fast infiltration of surface water, carrying the products of river and slope erosion and associated contaminants into the aquifer through the sinkholes. Several authors have shown the potential of turbidity as a marker of suspended elements transport and karst conduits fast transport. In this study, we conducted monthly monitoring of 11 boreholes located in the upstream watershed near boreholes (surveyed by the French Geological Survey BRGM): Graveron-Semerville in the Southern department of Upper Normandy (Eure) and Rocquemont in the Norhtern department of Upper Normandy (Seine-Maritime). The monitoring carried out included water level and electrical conductivity (reflecting total water mineralization) measurements, and major elements analysis. In any case, the water levels are similar over time (in accordance with the reference borehole). High mineralizations are observed in the Eure boreholes with significant anomalies of nitrate (70 to 130 mg/l ) and chloride (35 to 90 mg/l). For the Seine Maritime boreholes, no anomalies in nitrates and chlorides were found. To explain such differences, the agricultural activities are not sufficiently different from the study site. The explanation would then come from different reservoirs involved in water storage: loessic formations, thicker and more spreaded in the Seine Maritime department and clay with flints, of significantly higher thickness on average in the Eure department. We also discuss the influence of the drainage

  6. Experimental formation of chalk from calcareous ooze. Technical progress report

    SciTech Connect

    Seyfried, W.E.; Johnson, T.C.

    1981-02-15

    Samples of calcareous ooze collected from the tropical and equatorial Atlantic Ocean were subjected to hydrothermal alteration in order to simulate the diagenesis of chalk. Changes in mineralogy and morphology of enclosed microfossils were measured. (ACR)

  7. Horizontal well drilled into deep, hot Austin chalk

    SciTech Connect

    Pearce, D.; Johnson, M.; Godfrey, B.

    1995-04-03

    Bent-housing steerable downhole motors helped maintain course for a deep, hot, horizontal well in the Austin chalk. The Navasota Unit No. 1 was planned as a B zone, single downdip lateral, Austin chalk horizontal well with a maximum departure from vertical of 3,767 ft and a planned total depth (TD) of 17,342 ft measured depth (MD)/14,172 ft TVD. The Austin chalk was found significantly deeper in this well than planned, which resulted in an actual TD of 17,899 ft MD/14,993 ft TVD, the deepest (TVD) horizontal well in the Austin chalk to date. The well was spudded on August 6, 1994, and took 52 days to reach TD. The static bottom hole temperature was almost 350 F. The paper describes the well plan, drilling results, and the lateral section.

  8. The invertebrate ecology of the Chalk aquifer in England (UK)

    NASA Astrophysics Data System (ADS)

    Maurice, L.; Robertson, A. R.; White, D.; Knight, L.; Johns, T.; Edwards, F.; Arietti, M.; Sorensen, J. P. R.; Weitowitz, D.; Marchant, B. P.; Bloomfield, J. P.

    2016-03-01

    The Chalk is an important water supply aquifer, yet ecosystems within it remain poorly understood. Boreholes (198) in seven areas of England (UK) were sampled to determine the importance of the Chalk aquifer as a habitat, and to improve understanding of how species are distributed. Stygobitic macro-invertebrates were remarkably common, and were recorded in 67 % of boreholes in unconcealed Chalk, although they were not recorded in Chalk that is concealed by low-permeability strata and thus likely to be confined. Most species were found in shallow boreholes (<21 m) and boreholes with deep (>50 m) water tables, indicating that the habitat is vertically extensive. Stygobites were present in more boreholes in southern England than northern England (77 % compared to 38 %). Only two species were found in northern England compared to six in southern England, but overall seven of the eight stygobitic macro-invertebrate species found in England were detected in the Chalk. Two species are common in southern England, but absent from northern England despite the presence of a continuous habitat prior to the Devensian glaciation. This suggests that either they did not survive glaciations in the north where glaciers were more extensive, or dispersal rates are slow and they have never colonised northern England. Subsurface ecosystems comprising aquatic macro-invertebrates and meiofauna, as well as the microbial organisms they interact with, are likely to be widespread in the Chalk aquifer. They represent an important contribution to biodiversity, and may influence biogeochemical cycles and provide other ecosystem services.

  9. Influence of lithofacies and diagensis on Norwegian North Sea chalk reservoirs

    SciTech Connect

    Brasher, J.E.; Vagle, K.R.

    1996-05-01

    The depositional mechanism of chalk is a key influence in the chalk`s ultimate reservoir quality. Classically, the depositional mechanism is interpreted from core descriptions. Where core data are lacking, dipmeter and borehole imagery logs have proven useful in making lithofacies assessments. Criteria for recognition of three chalk categories are established. Category III chalks correspond to those chalks that have been deposited by gravity flows or slumping and tend to have the best reservoir parameters. Category I chalks are most often affiliated with pelagic deposition and tend to have the poorest reservoir parameters. Category II chalks are intermediate between I and III. Anomalously high primary porosities have been maintained in Norwegian North Sea chalks where the effects of mechanical and chemical compaction have been limited. The diagenetic pathway of a chalk reflects changes brought about by mechanical and chemical compaction. Five factors most heavily influence the diagenetic pathway: (1) burial depth, (2) chalk type, (3) overpressuring, (4) presence of hydrocarbons, and (5) original grain size. Assessments of the sedimentological model, diagenetic pathway, and resultant reservoir quality are provided in case studies of Edda, Tor, and Eldfisk fields. Because the distribution of chalk is largely independent of existing structures, most fields have a component of stratigraphic/diagenetic trapping. Each case study shows unique examples of how petrophysical and reservoir engineering data can be incorporated in assessments of chalk type and the diagenetic pathway and how they may affect reservoir parameters and productivity.

  10. Understanding heterogeneity in UK Chalk catchments and its influence on groundwater flooding

    NASA Astrophysics Data System (ADS)

    Peach, D. W.; Vounaki, T.; Jackson, C. R.; Hughes, A. G.; Wheater, H. S.

    2008-12-01

    The numerical simulation of groundwater flooding is increasingly necessary as this problem is gaining recognition from government and regulators and climate change may bring more extreme events. The Natural Environment Research Council of the UK is funding the British Geological Survey, Imperial College, and the Centre for Ecology and Hydrology to examine the problem of groundwater flooding in the Cretaceous Chalk of Berkshire, 50 kilometres west of London. Typically regional resource issues can be examined using traditional groundwater models that do not consider in detail the influence of flow in the unsaturated zone, but the delays in recharge transmission through this zone to the water table may be very significant in terms of flood timing and prediction. The position of ground elevation relative to water table is clearly important but not often considered in groundwater resource modelling. Groundwater level and stream (and flood) flow responses are important data that may be hard to gather from typical groundwater monitoring systems. These problems have been examined in a Chalk catchment in Berkshire where good records of the 2000-1 and 2003 flooding events have been collected, including flooded extent, rainfall, groundwater levels, river and spring flows. From this analysis, it appears that two groundwater mounds develop in the upper part of the Pang and Lambourn catchments. These mounds intersect dry valleys, which flowed for several months, the consequent flooding causing considerably disruption. Modelling of these events is providing new insight into the heterogeneity of Chalk transmissivity and storage parameters, enhanced knowledge of its dual permeability and porosity and demonstrating the importance of understanding the post-depositional hydrogeological history of the aquifer.

  11. End-cretaceous brachiopod extinctions in the chalk of denmark.

    PubMed

    Surlyk, F; Johansen, M B

    1984-03-16

    The results of a detailed study of the brachiopods of the most complete Cretaceous-Tertiary boundary in Denmark, Nye Klslashed circlev, show an extinction pattern for this marine invertebrate group compatible with that reported for pelagic foraminifera and coccoliths and with the impact scenario. The extinction is abrupt, coinciding with the Maastrichtian-Danian boundary. There is no warning in the form of decreasing density, decreasing diversity, or early extinction of specialized groups. The basal few meters of the Danian are almost devoid of brachiopods, and a Danian brachiopod fauna starts almost as abruptly as the Maastrichtian fauna disappeared. The new fauna is similar to the Maastrichtian as regards density and diversity, and at maximum six species are common to both stages. The northwest European Masstrichtian chalk is composed mainly of the remains of coccoliths and pelagic foraminifera. The mass extinction of these groups led to a total cessation of chalk production. The chalk is overlain by a thin clay bed deposited partly under anoxic conditions. This combination of anoxia and clay deposition coupled with a cessation of productivity led to the extinction of specialized groups such as the chalk brachiopods. The surviving species included forms that could survive in well-aerated shallow marine waters on substrates other than chalk.

  12. End-Cretaceous Brachiopod Extinctions in the Chalk of Denmark

    NASA Astrophysics Data System (ADS)

    Surlyk, Finn; Bagge Johansen, Marianne

    1984-03-01

    The results of a detailed study of the brachiopods of the most complete Cretaceous-Tertiary boundary in Denmark, Nye Klov, show an extinction pattern for this marine invertebrate group compatible with that reported for pelagic foraminifera and coccoliths and with the impact scenario. The extinction is abrupt, coinciding with the Maastrichtian-Danian boundary. There is no warning in the form of decreasing density, decreasing diversity, or early extinction of specialized groups. The basal few meters of the Danian are almost devoid of brachiopods, and a Danian brachiopod fauna starts almost as abruptly as the Maastrichtian fauna disappeared. The new fauna is similar to the Maastrichtian as regards density and diversity, and at maximum six species are common to both stages. The northwest European Maastrichtian chalk is composed mainly of the remains of coccoliths and pelagic foraminifera. The mass extinction of these groups led to a total cessation of chalk production. The chalk is overlain by a thin clay bed deposited partly under anoxic conditions. This combination of anoxia and clay deposition coupled with a cessation of productivity led to the extinction of specialized groups such as the chalk brachiopods. The surviving species included forms that could survive in well-aerated shallow marine waters on substrates other than chalk.

  13. Homing in on sweet spots in Cretaceous Austin chalk

    SciTech Connect

    Thomas, G.E. ); Sonnenberg, F.P.

    1993-11-29

    In discussing the nature and causes of fracturing in the Cretaceous Austin chalk of south central Texas, many geologists and operators involved in horizontal drilling of the chalk consider regional rock stress as the probable main cause of the fractures. If Austin chalk fractures are mainly the result of regional extensional stress without localizing factors, then fractured sweet spots are randomly distributed and successful exploration is more or less a matter of luck, usually dependent upon the coincidental placement of a seismic line. But if local, deep-seated structure or basement topography are the main causes of sweet spots, then a successful exploration method would be to first delineate the basement paleo structure or topography and secondly, place a seismic line to confirm the delineated features. Finding localities of maximum fracturing and production would than be based on scientific logic rather than luck. It is the purpose of this article to present the results of an examination of these alternative causes for the Austin chalk fracturing in the hope of determining the most cost effective exploration method for the fractured chalk reservoir.

  14. Gas/oil capillary pressure at chalk at elevated pressures

    SciTech Connect

    Christoffersen, K.R.; Whitson, C.H.

    1995-09-01

    Accurate capillary pressure curves are essential for studying the recovery of oil by gas injection in naturally fractured chalk reservoirs. A simple and fast method to determine high-pressure drainage capillary pressure curves has been developed. The effect of gas/oil interfacial tension (IFT) on the capillary pressure of chalk cores has been determined for a methane/n-pentane system. Measurements on a 5-md outcrop chalk core were made at pressures of 70, 105, and 130 bar, with corresponding IFT`s of 6.3, 3.2, and 1.5 mN/m. The results were both accurate and reproducible. The measured capillary pressure curves were not a linear function of IFT when compared with low-pressure centrifuge data. Measured capillary pressures were considerably lower than IFT-scaled centrifuge data. It appears that the deviation starts at an IFT of about 5 mN/m. According to the results of this study, the recovery of oil by gravity drainage in naturally fractured chalk reservoirs may be significantly underestimated if standard laboratory capillary pressure curves are scaled by IFT only. However, general conclusions cannot be made on the basis on only this series of experiments on one chalk core.

  15. Cyclic sedimentation, synsedimentary volcanism, microfabrics, and fracture intensity in the Austin Chalk, Texas

    SciTech Connect

    Hovorka, S.D. )

    1992-01-01

    Pelagic depositional environments of the Austin Chalk (Coniacian-Santonian) were influenced by sea-level variation, planktonic productivity, and allochthonous detrital input. Subtle differences in chalk facies influence fracture intensity, therefore imposing stratigraphic variability on hydrologic properties of the Austin Chalk. Variations in fracture intensity may affect ground-water flow through the Superconducting Super Collider (SSC) site south of Dallas in the same way that they influence hydrocarbon production in South Texas. The lower Austin Chalk was deposited during transgression. Glauconitic sandstone is overlain by cyclic chalk containing chalk-filled channels. Meter-thick chalk/marl cycles have frequencies in the Milankovitch spectrum. Marl accumulated during episodes of decreased planktonic productivity. Maximum flooding is indicated by organic-rich marls in the upper part of the Lower Austin Chalk. Shallowing during deposition of the middle and upper Austin Chalk is indicated by increasing abundance of winnowed lag deposits and firm grounds, resulting in increased faunal diversity. Authigenic clay, a product of alteration of volcanic ash codeposited with the chalk and marl, increases ductility in the middle Austin Chalk. The stratigraphic distribution of authigenic clay corresponds to disseminated biotite, quartz, and feldspar phenocrysts in most samples of the middle Austing Chalk. Authigenic clay decreases porosity, influences porosity-permeability relationships, and provides a regionally traceable low SP log response that correlates with low fracture intensity.

  16. What are the governing processes during low-flows in a chalk catchment?

    NASA Astrophysics Data System (ADS)

    Lubega Musuuza, Jude; Coxon, Gemma; Hutton, Chris; Howden, Nicholas; Woods, Ross; Freer, Jim; Wagener, Thorsten

    2016-04-01

    Low flows are important because they lead to the prioritisation of different consumptive water usages, imposition of restrictions and bans, raising of water tariffs and higher production costs to industry. The partitioning of precipitation into evaporation, storage and runoff depends on the local variability in meteorological variables and site-specific characteristics e.g., topography, soils and vegetation. The response of chalk catchments to meteorological forcing especially precipitation is of particular interest because of the preferential flow through the weathered formation. This makes the observed stream discharge groundwater-dominated and hence, out of phase with precipitation. One relevant question is how sensitive the low flow characteristics of such a chalk catchment is to changes in climate and land use. It is thus important to understand all the factors that control low stream discharge periods. In this study we present the results from numerical sensitivity analysis experiments performed with a detailed physically-based model on the Kennet, a sub-catchment of the River Thames, in the UK during the historical drought years of the 1970's.

  17. Horizontal spacing, depletion, and infill potential in the Austin Chalk

    SciTech Connect

    Kyte, D.G.; Meehan, D.N.

    1996-12-31

    There have been more than 4500 laterals drilled in the Austin Chalk. This paper looks at estimated ultimate recoveries (EUR) on a barrels/acre basis for these Austin Chalk wells. Baffels/acre recoveries were computed by estimating ultimate per-well recoveries, drilled density and the impact of vertical production. The data were then analyzed for depletion and infill potential. Certain areas were selected for further study using an artificial neural network. The network was built and used to study the effects of parameters such as lateral length, first production date, structure of the Austin Chalk, etc. on these recoverable barrel/acre numbers. The methodology and regional results of the study are reviewed with detailed analyses shown in selected areas.

  18. Human Geophagia, Calabash Chalk and Undongo: Mineral Element Nutritional Implications

    PubMed Central

    Abrahams, Peter W.; Davies, Theo C.; Solomon, Abiye O.; Trow, Amanda J.; Wragg, Joanna

    2013-01-01

    The prime aim of our work is to report and comment on the bioaccessible concentrations – i.e., the soluble content of chemical elements in the gastrointestinal environment that is available for absorption – of a number of essential mineral nutrients and potentially harmful elements (PHEs) associated with the deliberate ingestion of African geophagical materials, namely Calabash chalk and Undongo. The pseudo-total concentrations of 13 mineral nutrients/PHEs were quantified following a nitric-perchloric acid digestion of nine different Calabash chalk samples, and bioaccessible contents of eight of these chemical elements were determined in simulated saliva/gastric and intestinal solutions obtained via use of the Fed ORganic Estimation human Simulation Test (FOREhST) in vitro procedure. The Calabash chalk pseudo-total content of the chemical elements is often below what may be regarded as average for soils/shales, and no concentration is excessively high. The in vitro leachate solutions had concentrations that were often lower than those of the blanks used in our experimental procedure, indicative of effective adsorption: lead, a PHE about which concern has been previously raised in connection with the consumption of Calabash chalk, was one such chemical element where this was evident. However, some concentrations in the leachate solutions are suggestive that Calabash chalk can be a source of chemical elements to humans in bioaccessible form, although generally the materials appear to be only a modest supplier: this applies even to iron, a mineral nutrient that has often been linked to the benefits of geophagia in previous academic literature. Our investigations indicate that at the reported rates of ingestion, Calabash chalk on the whole is not an important source of mineral nutrients or PHEs to humans. Similarly, although Undongo contains elevated pseudo-total concentrations of chromium and nickel, this soil is not a significant source to humans for any of the

  19. Completion techniques for horizontal wells in the Pearsall Austin Chalk

    SciTech Connect

    Pope, C.D.; Handren, P.J. )

    1992-05-01

    Oryx Energy Co. used three basic completion techniques and various combinations of them to complete 20 horizontal wells in the Pearsall Austin Chalk. The completion method selected is based on a general set of guidelines. In this paper additionally, equipment selection and various types of workover operations are reviewed.

  20. Why Chalk Breaks into Three Pieces When Dropped

    ERIC Educational Resources Information Center

    Cross, Rod

    2015-01-01

    It has been the author's experience over many years, no doubt shared by others, that a stick of chalk usually breaks into three pieces when accidentally dropped onto the floor. I rarely gave it any thought, apart from noting that the fundamental mode of vibration of a freely supported, rigid rod has two nodes at an equal distance from each…

  1. Chalk-microfluidic: flooding microsystems with reactive fluids

    NASA Astrophysics Data System (ADS)

    Neuville, Amélie; Dysthe, Dag Kristian; Li, Lei; Hiorth, Aksel

    2014-05-01

    Experiments on core scale and field tests that have been carried out the last decade have clearly shown that water chemistry affects the final oil recovery. However, there is generally no consensus in the scientific community of why additional oil is released. Part of the reason for this is that there are very few in-situ observations of how the water chemistry affects fluid distributions on the pore scale, and/or the pore surface characteristics. In this work, as a first step, our aim is to focus on in-situ observations of single phase flow and interactions at the pore scale. In order to work at this small scale, we first investigate how to control the flow location. We propose to use the same principle as "paper-microfluidic": some areas of the chalk are chemically treated so that no fluid flows inside while other areas let the fluids flow in the chalk pores. Since chalk and paper obviously has different mechanical behavior, we need to adapt this technique. Custom-made microsystems with chalk and calcite will be presented. We will then show experiments with reacting fluids in these microsystems. These experiments are observed using wide field fluorescence microscopy and white light vertical/phase shift interferometric microscopy.

  2. Redox conditions in the Late Cretaceous Chalk Sea: the possible use of cerium anomalies as palaeoredox indicators in the Cenomanian and Turonian Chalk of England

    NASA Astrophysics Data System (ADS)

    Jeans, Christopher V.; Wray, David S.; Williams, C. Terry

    2015-09-01

    The cerium anomalies preserved in the Chalk have been investigated as possible palaeoredox indicators of the Late Cretaceous Sea and its sediment. This has been based upon over a hundred new rare earth element analyses of selected samples and grain size fractions from the Chalk. Particular attention has been given to the methodology of differentiating between the cerium anomalies preserved in the bioclastic calcite and those in carbonate-fluorapatite preserved in the acetic acid insoluble residues of chalks. Variations in the cerium anomaly of different particle size fractions of uncemented chalks suggest that fractionation of rare earth elements between the Chalk's seawater and the various organisms that contributed skeletal material to the bioclastic calcite of the Chalk may have occurred. Post-depositional processes of calcite cementation and late diagenetic sulphidisation have had no apparent effect on the cerium anomaly of the acetic acid insoluble residues. The cerium anomalies associated with the acetic acid insoluble residues from (1) an alternating sequence of chalks and marls from Ballard Cliff (Dorset, UK) typical of Milankovitch cyclicity show a marked diagenetic pattern, whereas those from (2) non-volcanic and volcanic marls display a pattern that is best explained by the variations in the availability of phosphorus and the timing of argillisation of volcanic glass during diagenesis. The general conclusion is drawn that the cerium anomalies preserved in the Chalk can provide an insight into the changing palaeoredox conditions in the Late Cretaceous Sea as well as in the pore fluids of its sediments.

  3. Seismic geomorphology of the Danish Chalks, offshore, North Sea

    NASA Astrophysics Data System (ADS)

    Smit, Florian; van Buchem, Frans; Schmidt, Ingelise

    2014-05-01

    The Upper Cretaceous and Lowermost Paleocene chalk deposits of the North Sea Basin constitute a unique phase in the evolution of carbonate facies, through the rock-forming dominance of fine grained calcareous plankton, particularly coccolithophorids. These planktonic organisms were deposited over extensive areas and very often laid down as laterally extensive, regular dm-scale bedded packages, that locally may reach a thickness of up to 1250 m. In the Danish Graben, the depositional conditions for the chalk sedimentation changed dramatically during the middle of the Upper Cretaceous. At this time the basin topography was inverted, radically changing the position of the depocenters and the ocean floor morphology. In uplifted areas local erosion and long phases of non-deposition occurred, whereas in areas of subsidence thick packages of chalk accumulated. Along the newly created highs, mass waste deposition took place at the deca-kilometre scale. In this presentation we will document evidence for the tectonic inversion, and pay particular attention to the rich pallet of geomorphological features that characterise this tectonically active period. This study benefitted from a recently re-processed 3D seismic dataset (6000 km²), and a regional well-log and biostratigraphic dataset. In addition, the seismic interpretation applied advanced seismic interpretation software (PaleoScan™), which uses a patented model grid that links up seismic points and honours interpreted horizon constraints resulting in a seismic Relative Geological Time model. Standard seismic attributes, displayed upon horizons from a 3D RGT model of the chalk package, have shown to be very effective in the illustration and interpretation of complex chalk depositional features. Special attention has been focussed on mass waste deposits around inverted structures and salt diapirs. Several different mass waste complexes have been documented in 3D, illustrating a number of typical features such as

  4. Correction and verification of AECL Bonner Sphere response matrix based on mono-energetic neutron calibration performed at NPL.

    PubMed

    Atanackovic, J; Thomas, D J; Roberts, N J; Witharana, S; Dubeau, J; Yonkeu, A

    2014-10-01

    The AECL Bonner Sphere Spectrometer (BSS) was taken to National Physical Laboratory (NPL) for calibration in mono-energetic neutron fields and bare (252)Cf neutron fields. The mono-energetic radiations were performed using ISO-8529 prescribed neutron energies: 0.071, 0.144, 0.565, 1.2, 5 and 17 MeV. A central SP9 proportional counter was also evaluated at the NPL thermal neutron calibration facility in order to assess an effective pressure of (3)He inside the counter, i.e. number density of (3)He atoms. Based on these measurements and methods outlined by Thomas and Soochak, a new BSS response matrix was generated. The response matrix is then verified by unfolding spectra corresponding to various neutron fields. Those are NPL bare (252)Cf source, National Institute of Standards and Technology bare and heavy water moderated (252)Cf source and (241)AmBe calibration source located at National Research Council. A good agreement was observed with expected neutron fluence rates, as well as derived dosimetric quantities, such as International Commission on Radiological Protection-74 ambient dose equivalent.

  5. Movement of Water Through the Chalk Unsaturated zone

    NASA Astrophysics Data System (ADS)

    Butler, A.; Ireson, A.; Wheater, H.; Mathias, S.; Finch, J.

    2006-12-01

    Despite many decades study, quantification of water movement through the Chalk unsaturated zone has proved difficult, due to its particular properties. Chalk comprises a fine grained porous matrix intersected by a fracture network. In much of the unsaturated zone, for most of the time, matric potentials remain between -20 and -0.5 m. Thus the matrix is largely saturated by capillary action, and the fractures are largely de-watered. Therefore, debate has often focussed on the importance of the fractures, as compared with the matrix, for the movement of water. Recently, Mathias et al. (J Hydrol., in press) and Brouyère (J Contam Hydrol,82:195-219,2006) have (independently) proposed an Equivalent Continuum Model, ECM, for the Chalk. This assumes that the fractures can be treated as a porous medium and that the fracture and matrix domains can be treated as a single domain i.e. an equivalent continuum. This requires that the fractures and matrix are in pressure equilibrium, and whilst the theoretical basis for this assumption is reasonable, it has not been demonstrated empirically. In addition, Mathias et al. have demonstrated the importance of rainfall attenuation in the near surface weathered and soil zones of the Chalk for attenuating flow. As part of a national research initiative into groundwater dominated catchments, an extensive field monitoring programme has been implemented at two Chalk catchments in Berkshire (UK). This includes comprehensive soil moisture measurements (water content and matric potential), an extensive network of piezometers and observation wells measuring water table response, and the direct measurement of actual evaporation as well as standard meteorological variables, including rainfall. Using the Kosugi (WRR,32:2697-2703,1996) relationships for soil water retention and hydraulic conductivity a methodology for characterising vertical variation in hydraulic properties from competent chalk at depth through weathered rock to surface soil has

  6. Horizontal wells up odds for profit in Giddings Austin chalk

    SciTech Connect

    Maloy, W.T. )

    1992-02-17

    This paper reports on horizontal drilling in the Giddings field Austin chalk which has significantly improved average well recoveries and more than offset increased drilling costs. Although not the panacea originally promoted, horizontal drilling, in Giddings field, offers economic profits to the average investor. Economic analysis indicates that the typical investor is making money by earning returns in excess of market values. Field-wide development will, therefore, remain active unless oil prices or average well recoveries fall below $12/bbl or 112,000 bbl of oil equivalent (BOE), respectively. The application of technological innovation in the Giddings field may culminate in the drilling of over 2,000 horizontal Austin chalk wells, and has conceivably increased recoverable reserves by 400 million BOE.

  7. Maternal Geophagy of Calabash Chalk on Foetal Cerebral Cortex Histomorphology

    PubMed Central

    EKANEM, Theresa Bassey; EKONG, Moses Bassey; ELUWA, Mokutima Amarachi; IGIRI, Anozeng Oyono; OSIM, Eme Efiom

    2015-01-01

    Background: Calabash chalk, a kaolin-base substance is a common geophagic material mostly consumed by pregnant women. This study investigated its effect on the histomorphology of the foetal cerebral cortex. Methods: Twelve gestating Wistar rats were divided equally into groups 1 and 2. On pregnancy day seven (PD7), group 2 animals were administered 200 mg/kg body weight of calabash chalk suspension, while group 1 animals served as the control and received 1 ml of distilled water, by oral gavages and for 14 days (PD7-PD20). On PD21, the dams were sacrificed, and the foetuses removed, examined for gross malformations, weighed and culled to two foetuses per mother. Their whole brains were excised, weighed and preserved using 10% buffered formalin, and routinely processed by haematoxylin and eosin, and Luxol fast blue methods. Results: The foetuses showed no morphological change, but their mean body weights was higher (p=0.0001). Histomorphological sections of the cerebral cortex showed hypertrophy and hyperplasia of cells in all the cortical layers, with less demonstrated Nissl and higher (p=0.001) cellular population compared with the control group. Conclusion: Calabash chalk cause body weight increase and histomorphological changes in the cerebral cortex of foetuses. PMID:26715904

  8. Horizontal technology helps spark Louisiana`s Austin chalk trend

    SciTech Connect

    Koen, A.D.

    1996-04-29

    A handful of companies paced by some of the most active operators in the US are pressing the limits of horizontal technology to ramp up Cretaceous Austin chalk exploration and development (E and D) across Louisiana. Companies find applications in Louisiana for lessons learned drilling horizontal wells to produce chalk intervals in Texas in Giddings, Pearsall, and Brookeland fields. Continuing advances in horizontal well technology are helping operators deal with deeper, hotter reservoirs in more complex geological settings that typify the chalk in Louisiana. Better horizontal drilling, completion, formation evaluation, and stimulation techniques have enabled operators to produce oil and gas from formations previously thought to be uneconomical. Most of the improved capabilities stem from better horizontal tools. Horizontal drilling breakthroughs include dual powered mud motors and retrievable whipstocks, key links in the ability to drill wells with more than one horizontal lateral. Better geosteering tools have enabled operators to maintain horizontal wellbores in desired intervals by signaling bit positions downhole while drilling. This paper reviews the technology and provides a historical perspective on the various drilling programs which have been completed in this trend. It also makes predictions on future drilling successes.

  9. Why Chalk Breaks into Three Pieces When Dropped

    NASA Astrophysics Data System (ADS)

    Cross, Rod

    2015-01-01

    It has been the author's experience over many years, no doubt shared by others, that a stick of chalk usually breaks into three pieces when accidentally dropped onto the floor. I rarely gave it any thought, apart from noting that the fundamental mode of vibration of a freely supported, rigid rod has two nodes at an equal distance from each end. For example, a baseball bat has a node in the barrel (the sweet spot) about 15 cm from the end and another node in the handle. However, chalk is not expected to break at the node points, since maximum stress arises at the antinode in the middle of the chalk where bending is a maximum. Richard Feynman described a similar problem with long sticks of spaghetti.1 He found that they always break into three or more pieces when bent slowly beyond their breaking point, rather than simply breaking in half. He was unable to figure out why, although the problem was solved many years later2 and is nicely illustrated by Vollmer and Mollmann.3

  10. Sulfur isotope patterns of iron sulfide and barite nodules in the Upper Cretaceous Chalk of England and their regional significance in the origin of coloured chalks

    NASA Astrophysics Data System (ADS)

    Jeans, Christopher V.; Turchyn, Alexandra V.; Hu, Xu-Fang

    2016-06-01

    The relationship between the development of iron sulfide and barite nodules in the Cenomanian Chalk of England and the presence of a red hematitic pigment has been investigated using sulfur isotopes. In southern England where red and pink chalks are absent, iron sulfide nodules are widespread. Two typical large iron sulfide nodules exhibit δ34S ranging from -48.6‰ at their core to -32.6‰ at their outer margins. In eastern England, where red and pink chalks occur in three main bands, there is an antipathetic relationship between the coloured chalks and the occurrence of iron sulfide or barite nodules. Here iron sulfide, or its oxidised remnants, are restricted to two situations: (1) in association with hard grounds that developed originally in chalks that contained the hematite pigment or its postulated precursor FeOH3, or (2) in regional sulfidization zones that cut across the stratigraphy. In the Cenomanian Chalk exposed in the cliffs at Speeton, Yorkshire, pyrite and marcasite (both iron sulfide) nodules range in δ34S from -34.7‰ to +40.0‰. In the lower part of the section δ34S vary from -34.8‰ to +7.8‰, a single barite nodule has δ34S between +26.9‰ and +29.9‰. In the middle part of the section δ34S ranges from +23.8‰ to +40.0‰. In the sulfidization zones that cut across the Cenomanian Chalk of Lincolnshire the iron sulfide nodules are typically heavily weathered but these may contain patches of unoxidised pyrite. In these zones, δ34S ranges from -32.9‰ to +7.9‰. The cross-cutting zones of sulfidization in eastern England are linked to three basement faults - the Flamborough Head Fault Zone, the Caistor Fault and the postulated Wash Line of Jeans (1980) - that have affected the deposition of the Chalk. It is argued that these faults have been both the conduits by which allochthonous fluids - rich in hydrogen sulfide/sulfate, hydrocarbons and possibly charged with sulfate-reducing bacteria - have penetrated the Cenomanian Chalk as

  11. Fractal characterization of a fractured chalk reservoir - The Laegerdorf case

    SciTech Connect

    Stoelum, H.H.; Koestler, A.G.; Feder, J.; Joessang, T.; Aharony, A.

    1991-03-01

    What is the matrix block size distribution of a fractured reservoir In order to answer this question and assess the potential of fractal geometry as a method of characterization of fracture networks, a pilot study has been done of the fractured chalk quarry in Laegerdorf. The fractures seen on the quarry walls were traced in the field for a total area of {approximately}200 {times} 45 m. The digitized pictures have been analyzed by a standard box-counting method. This analysis gave a fractal dimension of similarity varying from 1.33 for fractured areas between faults, to 1.43 for the fault zone, and 1.53 for the highly deformed fault gouge. The amplitude showed a similar trend. The fractal dimension for the whole system of fractures is {approximately}1.55. In other words, fracture networks in chalk have a nonlinear, fractal geometry, and so matrix block size is a scaling property of chalk reservoirs. In terms of rock mechanics, the authors interpret the variation of the fractal dimension as follows: A small fractal dimension and amplitude are associated with brittle deformation in the elastic regime, while a large fractal dimension and amplitude are associated with predominantly ductile, strain softening deformation in the plastic regime. The interaction between the two regimes of deformation in the rock body is a key element of successful characterization and may be approached by seeing the rock as a non-Newtonian viscoelastic medium. The fractal dimension for the whole is close to a material independent limit that constrains the development of fractures.

  12. Fault zone processes in mechanically layered mudrock and chalk

    NASA Astrophysics Data System (ADS)

    Ferrill, David A.; Evans, Mark A.; McGinnis, Ronald N.; Morris, Alan P.; Smart, Kevin J.; Wigginton, Sarah S.; Gulliver, Kirk D. H.; Lehrmann, Daniel; de Zoeten, Erich; Sickmann, Zach

    2017-04-01

    A 1.5 km long natural cliff outcrop of nearly horizontal Eagle Ford Formation in south Texas exposes northwest and southeast dipping normal faults with displacements of 0.01-7 m cutting mudrock, chalk, limestone, and volcanic ash. These faults provide analogs for both natural and hydraulically-induced deformation in the productive Eagle Ford Formation - a major unconventional oil and gas reservoir in south Texas, U.S.A. - and other mechanically layered hydrocarbon reservoirs. Fault dips are steep to vertical through chalk and limestone beds, and moderate through mudrock and clay-rich ash, resulting in refracted fault profiles. Steeply dipping fault segments contain rhombohedral calcite veins that cross the fault zone obliquely, parallel to shear segments in mudrock. The vertical dimensions of the calcite veins correspond to the thickness of offset competent beds with which they are contiguous, and the slip parallel dimension is proportional to fault displacement. Failure surface characteristics, including mixed tensile and shear segments, indicate hybrid failure in chalk and limestone, whereas shear failure predominates in mudrock and ash beds - these changes in failure mode contribute to variation in fault dip. Slip on the shear segments caused dilation of the steeper hybrid segments. Tabular sheets of calcite grew by repeated fault slip, dilation, and cementation. Fluid inclusion and stable isotope geochemistry analyses of fault zone cements indicate episodic reactivation at 1.4-4.2 km depths. The results of these analyses document a dramatic bed-scale lithologic control on fault zone architecture that is directly relevant to the development of porosity and permeability anisotropy along faults.

  13. Groundwater recharge dynamics in unsaturated fractured chalk: a case study

    NASA Astrophysics Data System (ADS)

    Cherubini, Claudia; Pastore, Nicola; Giasi, Concetta I.; Allegretti, Nicolaetta M.

    2016-04-01

    The heterogeneity of the unsaturated zone controls its hydraulic response to rainfall and the extent to which pollutants are delayed or attenuated before reaching groundwater. It plays therefore a very important role in the recharge of aquifers and the transfer of pollutants because of the presence of temporary storage zones and preferential flows. A better knowledge of the physical processes in the unsaturated zone would allow an improved assessment of the natural recharge in a heterogeneous aquifer and of its vulnerability to surface-applied pollution. The case study regards the role of the thick unsaturated zone of the Cretaceous chalk aquifer in Picardy (North of France) that controls the hydraulic response to rainfall. In the North Paris Basin, much of the recharge must pass through a regional chalk bed that is composed of a porous matrix with embedded fractures. Different types of conceptual models have been formulated to explain infiltration and recharge processes in the unsaturated fractured rock. The present study analyses the episodic recharge in fractured Chalk aquifer using the kinematic diffusion theory to predict water table fluctuation in response to rainfall. From an analysis of the data, there is the evidence of 1) a seasonal behavior characterized by a constant increase in the water level during the winter/spring period and a recession period, 2) a series of episodic behaviors during the summer/autumn. Kinematic diffusion models are useful for predict preferential fluxes and dynamic conditions. The presented approach conceptualizes the unsaturated flow as a combination of 1) diffusive flow refers to the idealized portion of the pore space of the medium within the flow rate is driven essentially by local gradient of potential; 2) preferential flow by which water moves across macroscopic distances through conduits of macropore length.

  14. A geological assessment: What`s ahead for Louisiana Austin chalk

    SciTech Connect

    Maloy, W.T.

    1997-06-02

    Both noteworthy and recent, the extension of the Austin chalk horizontal drilling play into Louisiana has been as closely watched as it has been controversial. The play has been controversial for the critics who claim the Louisiana chalk boom is simply the latest chapter in the chalk`s boom and bust history. The play is closely watched by chalk enthusiasts who have seen Louisiana horizontal wells yield as much as 80,000 bbl of oil and 250 MMcf of gas in a single month. Who is right? How will the play develop? This article presents a geological assessment of the play and offers some insights into the future of horizontal drilling in Louisiana.

  15. A unique Austin Chalk reservoir, Van field, Van Zandt County, Texas

    SciTech Connect

    Lowe, J.T. )

    1990-09-01

    Significant shallow oil production from the Austin Chalk was established in the Van field, Van Zandt County, in East Texas in the late 1980s. The Van field structure is a complexly faulted domal anticline created by salt intrusion. The Woodbine sands, which underlie the Austin Chalk, have been and continue to be the predominant reservoir rocks in the field. Evidence indicates that faults provided vertical conduits for migration of Woodbine oil into the Austin Chalk where it was trapped along the structural crest. The most prolific Austin Chalk production is on the upthrown side of the main field fault, as is the Woodbine. The Austin Chalk is a soft, white to light gray limestone composed mostly of coccoliths with some pelecypods. Unlike the Austin Chalk in the Giddings and Pearsall fields, the chalk at Van was not as deeply buried and therefore did not become brittle and susceptible to tensional or cryptic fracturing. The shallow burial in the Van field was also important in that it allowed the chalk to retain primary microporosity. The production comes entirely from this primary porosity. In addition to the structural position and underlying oil source from the Woodbine, the depositional environment and associated lithofacies are also keys to the reservoir quality in the Van field as demonstrated by cores from the upthrown and downthrown (less productive) sides of the main field fault. It appears that at the time of Austin Chalk deposition, the main field fault was active and caused the upthrown side to be a structural high and a more agreeable environment for benthonic organisms such as pelecypods and worms. The resulting bioturbation enhanced the reservoir's permeability enough to allow migration and entrapment of the oil. Future success in exploration for analogous Austin Chalk reservoirs will require the combination of a favorable environment of deposition, a nearby Woodbine oil source, and a faulted trap that will provide the conduit for migration.

  16. Horizontal gas-condensate find brightens Louisiana chalk outlook

    SciTech Connect

    Petzet, G.A.

    1994-12-19

    A ray of hope may have appeared in the Louisiana portion of the Cretaceous Austin chalk trend after several years of expensive disappointment. OXY USA Inc. plans to use dual leg horizontal wells to develop a fracture chalk reservoir named Masters Creek field in Rapides Parish. The state has approved four 1,920 acre spacing units, one of which contains OXY's A1 Monroe well. The A1 Monroe flowed 6.6 MMcfd of gas with 2,162 b/d of 48[degree] gravity condensate, not oil as previously reported, through a 26/64 in. choke with 6,196 psi flowing tubing pressure from a single southward 4,000 ft horizontal leg at 14,803 ft true vertical depth. Bottomhole pressure is 13,100 psi. OXY called A1 Monroe a significant discovery and said it has additional exploration acreage blocks along the trend. Louisiana exempts production from horizontal wells from state severance tax until all project costs are returned. The paper briefly discusses OXY's program.

  17. Laboratory determination of effective stress laws for deformation and permeability of chalk

    SciTech Connect

    Teufel, L W; Warpinski, N R

    1990-01-01

    Laboratory deformation and permeability measurements have been made on chalk samples from Ekofisk area fields as a function of confining stress and pore pressure to determine the effective stress laws for chalk. An understanding of the effective stress law is essential to obtain correct reservoir-property data from core analysis and is critical for reservoir management studies and reservoir compaction models. A powerful statistical technique known as the response surface method has been used to analyze our laboratory data determine the form of the effective stress law for deformation and permeability. Experiments were conducted on chalk samples that had a range of porosities from 15% to 36%, because porosity is the dominant intrinsic property that effects deformation and permeability behavior of chalk. Deformation of a 36% porosity chalk was highly nonlinear, but the effective stress law was linear, with {alpha} equal to about unity. Lower-porosity samples showed linear strain behavior and a linear effective stress law with {alpha} as low as 0.74. Analysis of the effective stress law for permeability is presented only for the lowest porosity chalk sample because changes in permeability in the higher-porosity chalk samples due to increasing confining stress or pore pressure were not were large enough, to deduce meaningful effective stress relationships. 15 refs., 8 figs., 2 tabs.

  18. Chalk as the carrier for nitrifying biofilm in a fluidized bed reactor.

    PubMed

    Green, M; Ruskol, Y; Lahav, O; Tarre, S

    2001-01-01

    A fluidized bed reactor for nitrification with chalk as the biomass carrier and the sole buffer agent was studied. Chalk dissolution in the reactor was found to follow the stoichiometric ratio of 1 mole of CaCO3 dissolved for each mole of NH4+ oxidized. Three batches of chalk, each one having a different dissolution rate, were used to replace the dissolved chalk. The three dissolution rates resulted in three different steady state pH levels in the reactor (4.7-6.6) and nitrification rates. Nitrification was found to be limited by either the chalk dissolution rate or dissolved oxygen concentration depending on the type of chalk used. A maximal nitrification rate of 1.44 g NH4(+)-N/l reactor.d was observed. The average cell yield was 0.1 g cells/g N oxidized, similar to the cell yield during reactor start-up when the pH was 7. The specific ammonium oxidation rates varied between 0.08 and 0.15 mg NH4(+)-N oxidized/mg protein.h, values which are in the reported range for nitrification at pH 7 to 8. Oxygen update rate (OUR) results indicated that the major mechanism responsible for the high nitrification rate observed in the reactor operating at low pH seems to be the favorable microenvironment provided by the chalk.

  19. Seismic architecture of the Chalk Group from onshore reflection data in eastern Denmark

    NASA Astrophysics Data System (ADS)

    Moreau, Julien; Anderskouv, Kresten; Boldreel, Lars Ole; Boussaha, Myriam; Nielsen, Lars; Stemmerik, Lars; Surlyk, Finn; Thibault, Nicolas

    2013-04-01

    The Upper Cretaceous-Danian chalk is well exposed in the 14 km long coastal cliff of Stevns Klint (eastern Denmark). The cliff is a world renowned for its spectacular exposure of the Cretaceous-Palaeogene boundary. Based on regional geological knowledge of the field and cores, the characteristics of the Chalk Group have been well constrained. Distinct sedimentary facies have been encountered; the sedimentology, the biostratigraphy, the diagenesis and the reservoir properties have been thoroughly investigated and reported. Stimulated by the intensive geological research, the field studies have been completed with the acquisition of an extensive set of subsurface data. The data include high resolution 2D multichannel seismics onshore and offshore, a seismic refraction profile, two entirely cored boreholes including wireline logs, GPR cross-hole tomography, thermographic analysis, etc. We intend to compile and merge the geological and geophysical datasets to investigate the variation of the Chalk Group properties and their signature in the subsurface. In this communication, the seismic reflection data are being analysed. Very high resolution litho-, bio- and cyclostratigraphy can be correlated with the seismic stratigraphy. Several seismic facies are identified in the Chalk Group: the 'transparent' (white chalk), the stratified (marl-chalk alternations), the crudely stratified (flint-rich chalk) and the hummocky (bryozoan mounds). The units notably vary in thickness at a relatively small scale. The variations confirm the complex shelf organisation which was highly influenced by bottom currents. In addition to the stratigraphic observations, peculiar deformation structures can be recognised. The area has been supposedly tectonically stable since deposition as the coastal cliff lacks fault offset but the succession has been uplifted of c. 1 km. The main fracture patterns are associated with the recent unloading of the ice, opening shallow horizontal fractures

  20. Diffusive parameters of tritiated water and uranium in chalk

    SciTech Connect

    Descostes, M.; Pili, E.; Felix, O.; Frasca, B.; Radwan, J.; Juery, A.

    2012-07-15

    The Cretaceous Chalk of North-western Europe exhibits a double porosity (matrix and fracture) providing pathways for both slow and rapid flow of water. The present study aims at understanding and predicting the contaminant transfer properties through a significant section of this formation, with a particular emphasis on diffusion. This requires to study the nature of porosity and to perform diffusion experiments in representative samples using uranium and tritiated water (HTO), respectively taken as a reactive tracer and an inert one. The diffusive parameters, i.e. the accessible porosity and the effective diffusion coefficient were determined. Additional information was obtained with mercury porosimetry, gravimetric water content, textural and mineralogical characterization. The diffusion tests performed with HTO appear to be the best method to measure the total accessible porosity in any type of porous media, especially those having large pore size distributions. Our study demonstrates that classical gravimetric water content measurements are not sensitive to the reduction in pore size as opposed to HTO diffusion tests because capillary water is not extracted by conventional gravimetric method but can still be probed by diffusion experiments. We found effective diffusion coefficients D{sub e}(U(VI)) near 4 x 10{sup -10} m{sup 2}s{sup -1}). The slower migration of U(VI) compared to HTO indicates sorption, with R{sub d}(U(VI)) from 100 to 360 mL g{sup -1}. These values are one order of magnitude larger than other determinations of the U(VI) sorption coefficient because only the matrix porosity is concerned here. The migration of U(VI) in chalk is only limited by sorption on ancillary Fe-Pb-bearing minerals. Transport of HTO and U(VI) is independent of the porosity distribution. Uranium diffusion in the chalk matrix porosity is fast enough to allow the total invasion of the pore space within characteristic time scales of the order of 1000 years. This results in a

  1. Nitrogen speciation and phosphorus fractionation dynamics in a lowland Chalk catchment.

    PubMed

    Yates, C A; Johnes, P J

    2013-02-01

    A detailed analysis of temporal and spatial trends in nitrogen (N) speciation and phosphorus (P) fractionation in the Wylye, a lowland Chalk sub-catchment of the Hampshire Avon, UK is presented, identifying the sources contributing to nutrient enrichment, and temporal variability in the fractionation of nutrients in transit from headwaters to lower reaches of the river. Samples were collected weekly from ten monitoring stations with daily sampling at three further sites over one year, and monthly inorganic N and total reactive P (TRP) concentrations at three of the ten weekly monitoring stations over a ten year period are also presented. The data indicate significant daily and seasonal variation in nutrient fractionation in the water column, resulting from plant uptake of dissolved organic and inorganic nutrient fractions in the summer months, increased delivery of both N and P from diffuse sources in the autumn to winter period and during high flow events, and lack of dilution of point source discharges to the Wylye from septic tank, small package Sewage Treatment Works (STW) and urban Waste Water Treatment Works (WwTW) during the summer low flow period. Weekly data show that contributing source areas vary along the river with headwater N and P strongly influenced by diffuse inorganic N and particulate P fluxes, and SRP and organic-rich point source contributions from STW and WwTW having a greater influence in the lower reaches. Long-term data show a decrease in TRP concentrations at all three monitoring stations, with the most pronounced decrease occurring downstream from Warminster WwTW, following the introduction of P stripping at the works in 2001. Inorganic N demonstrates no statistically significant change over the ten year period of record in the rural headwaters, but an increase in the lower reaches downstream from the WwTW which may be due to urban expansion in the lower catchment.

  2. Towards a simple representation of chalk hydrology in land surface modelling

    NASA Astrophysics Data System (ADS)

    Rahman, Mostaquimur; Rosolem, Rafael

    2017-01-01

    Modelling and monitoring of hydrological processes in the unsaturated zone of chalk, a porous medium with fractures, is important to optimize water resource assessment and management practices in the United Kingdom (UK). However, incorporating the processes governing water movement through a chalk unsaturated zone in a numerical model is complicated mainly due to the fractured nature of chalk that creates high-velocity preferential flow paths in the subsurface. In general, flow through a chalk unsaturated zone is simulated using the dual-porosity concept, which often involves calibration of a relatively large number of model parameters, potentially undermining applications to large regions. In this study, a simplified parameterization, namely the Bulk Conductivity (BC) model, is proposed for simulating hydrology in a chalk unsaturated zone. This new parameterization introduces only two additional parameters (namely the macroporosity factor and the soil wetness threshold parameter for fracture flow activation) and uses the saturated hydraulic conductivity from the chalk matrix. The BC model is implemented in the Joint UK Land Environment Simulator (JULES) and applied to a study area encompassing the Kennet catchment in the southern UK. This parameterization is further calibrated at the point scale using soil moisture profile observations. The performance of the calibrated BC model in JULES is assessed and compared against the performance of both the default JULES parameterization and the uncalibrated version of the BC model implemented in JULES. Finally, the model performance at the catchment scale is evaluated against independent data sets (e.g. runoff and latent heat flux). The results demonstrate that the inclusion of the BC model in JULES improves simulated land surface mass and energy fluxes over the chalk-dominated Kennet catchment. Therefore, the simple approach described in this study may be used to incorporate the flow processes through a chalk unsaturated

  3. Chalk-Ex: Transport of Optically Active Particles from the Surface Mixed Layer

    DTIC Science & Technology

    2005-05-02

    dissolution , aggregation, and grazing- related "repackaging" into fecal pellets). Approach The focus of the Chalk-Ex project was a sequence of...experiment in which the production term of optically-active particles could be defined, significantly reducing the uncertainty of the net loss rates of...suspended calcite algorithm. The NASA project paid for the 26 T of chalk and some of the ship time for the November 2001 experiments. A DURIP Grant to J

  4. Rivers

    USGS Publications Warehouse

    Leopold, Luna Bergere

    1962-01-01

    Rivers are both the means and the routes by which the products of continental weathering are carried to the oceans of the world. Except in the most arid areas more water falls as precipitation than is lost by evaporation and transpiration from the land surface to the atmosphere. Thus there is an excess of water, which must flow to the ocean. Rivers, then, are the routes by which this excess water flows to the ultimate base level. The excess of precipitation over evaporation and transpiration provides the flow of rivers and springs, recharges ground-water storage, and is the supply from which man draws water for his needs.

  5. The effect of chalk on the finger-hold friction coefficient in rock climbing.

    PubMed

    Amca, Arif Mithat; Vigouroux, Laurent; Aritan, Serdar; Berton, Eric

    2012-11-01

    The main purpose of this study was to examine the effect of chalk on the friction coefficient between climber's fingers and two different rock types (sandstone and limestone). The secondary purpose was to investigate the effects of humidity and temperature on the friction coefficient and on the influence of chalk. Eleven experienced climbers took part in this study and 42 test sessions were performed. Participants hung from holds which were fixed on a specially designed hang board. The inclination of the hang board was progressively increased until the climber's hand slipped from the holds. The angle of the hang board was simultaneously recorded by using a gyroscopic sensor and the friction coefficient was calculated at the moment of slip. The results showed that there was a significant positive effect of chalk on the coefficient of friction (+18.7% on limestone and +21.6% on sandstone). Moreover sandstone had a higher coefficient of friction than limestone (+15.6% without chalk, +18.4% with chalk). These results confirmed climbers' belief that chalk enhances friction. However, no correlation with humidity/temperature and friction coefficient was noted which suggested that additional parameters should be considered in order to understand the effects of climate on finger friction in rock climbing.

  6. Reactive transport modelling of groundwater chemistry in a chalk aquifer at the watershed scale.

    PubMed

    Mangeret, A; De Windt, L; Crançon, P

    2012-09-01

    This study investigates thermodynamics and kinetics of water-rock interactions in a carbonate aquifer at the watershed scale. A reactive transport model is applied to the unconfined chalk aquifer of the Champagne Mounts (France), by considering both the chalk matrix and the interconnected fracture network. Major element concentrations and main chemical parameters calculated in groundwater and their evolution along flow lines are in fair agreement with field data. A relative homogeneity of the aquifer baseline chemistry is rapidly reached in terms of pH, alkalinity and Ca concentration since calcite equilibrium is achieved over the first metres of the vadose zone. However, incongruent chalk dissolution slowly releases Ba, Mg and Sr in groundwater. Introducing dilution effect by rainwater infiltration and a local occurrence of dolomite improves the agreement between modelling and field data. The dissolution of illite and opal-CT, controlling K and SiO(2) concentrations in the model, can be approximately tackled by classical kinetic rate laws, but not the incongruent chalk dissolution. An apparent kinetic rate has therefore been fitted on field data by inverse modelling: 1.5×10(-5) mol(chalk)L (-1) water year (-1). Sensitivity analysis indicates that the CO(2) partial pressure of the unsaturated zone is a critical parameter for modelling the baseline chemistry over the whole chalk aquifer.

  7. 3D characterization of the fracture network in a deformed chalk reservoir analogue: The Lagerdorf case

    SciTech Connect

    Koestler, A.G.; Reksten, K.

    1994-12-31

    Quantitative descriptions of the 3D fracture networks in terms of connectivity, fracture types, fracture surface roughness and flow characteristics are necessary for reservoir evaluation, management, and enhanced oil recovery programs of fractured reservoirs. For a period of 2 years, a research project focused on an analogue to fractured chalk reservoirs excellently exposed near Laegerdorf, NW Germany. Upper Cretaceous chalk has been uplifted and deformed by an underlying salt diapir, and is now exploited for the cement industry. In the production wall of a quarry, the fracture network of the deformed chalk was characterized and mapped at different scales. The wall was scraped off as chalk exploitation proceeded, continuously revealing new sections through the faulted and fractured chalk body. A 230 m long part of the 35m high production wall was investigated during its recess of 25m. The large amount of fracture data were analyzed with respect to parameters such as fracture density distribution, orientation- and length distribution, and in terms of the representativity of data sets collected from restricted rock volumes. This 3D description and analysis of a fracture network revealed quantitative generic parameters of importance for modeling chalk reservoirs with less data and lower data quality.

  8. Trace elemental analysis of school chalk using energy dispersive X-ray florescence spectroscopy (ED-XRF)

    NASA Astrophysics Data System (ADS)

    Maruthi, Y. A.; Das, N. Lakshmana; Ramprasad, S.; Ram, S. S.; Sudarshan, M.

    2015-08-01

    The present studies focus the quantitative analysis of elements in school chalk to ensure the safety of its use. The elements like Calcium (Ca), Aluminum (Al), Iron (Fe), Silicon (Si) and Chromium (Cr) were analyzed from settled chalk dust samples collected from five classrooms (CD-1) and also from another set of unused chalk samples collected from local market (CD-2) using Energy Dispersive X-Ray florescence(ED-XRF) spectroscopy. Presence of these elements in significant concentrations in school chalk confirmed that, it is an irritant and occupational hazard. It is suggested to use protective equipments like filtered mask for mouth, nose and chalk holders. This study also suggested using the advanced mode of techniques like Digital boards, marker boards and power point presentations to mitigate the occupational hazard for classroom chalk

  9. Trace elemental analysis of school chalk using energy dispersive X-ray florescence spectroscopy (ED-XRF)

    SciTech Connect

    Maruthi, Y. A.; Das, N. Lakshmana; Ramprasad, S.; Ram, S. S.; Sudarshan, M.

    2015-08-28

    The present studies focus the quantitative analysis of elements in school chalk to ensure the safety of its use. The elements like Calcium (Ca), Aluminum (Al), Iron (Fe), Silicon (Si) and Chromium (Cr) were analyzed from settled chalk dust samples collected from five classrooms (CD-1) and also from another set of unused chalk samples collected from local market (CD-2) using Energy Dispersive X-Ray florescence(ED-XRF) spectroscopy. Presence of these elements in significant concentrations in school chalk confirmed that, it is an irritant and occupational hazard. It is suggested to use protective equipments like filtered mask for mouth, nose and chalk holders. This study also suggested using the advanced mode of techniques like Digital boards, marker boards and power point presentations to mitigate the occupational hazard for classroom chalk.

  10. Colloid facilitated transport of lanthanides through discrete fractures in chalk

    NASA Astrophysics Data System (ADS)

    Tran, Emily; Klein Ben-David, Ofra; Teutsch, Nadya; Weisbrod, Noam

    2015-04-01

    Geological disposal of high-level radioactive waste is the internationally agreed-upon, long term solution for the disposal of long lived radionuclides and spent fuel. Eventually, corrosion of the waste canisters may lead to leakage of their hazardous contents, and the radionuclides can ultimately make their way into groundwater and pose a threat to the biosphere. Engineered bentonite barriers placed around nuclear waste repositories are generally considered sufficient to impede the transport of radionuclides from their storage location to the groundwater. However, colloidal-sized mobile bentonite particles eroding from these barriers have come under investigation as a potential transport vector for radionuclides sorbed to them. In addition, the presence of organic matter in groundwater has been shown to additionally facilitate the uptake of radionuclides by the clay colloids. This study aims to evaluate the transport behaviors of radionuclides in colloid-facilitated transport through a fractured chalk matrix and under geochemical conditions representative of the Negev desert, Israel. Lanthanides are considered an acceptable substitute to actinides for research on radionuclide transportation due to their similar chemical behavior. In this study, the migration of Ce both with and without colloidal particles was explored and compared to the migration of a conservative tracer (bromide). Tracer solutions containing known concentrations of Ce, bentonite colloids, humic acid and bromide were prepared in a matrix solution containing salt concentrations representative of that of the average rain water found in the Negev. These solutions were then injected into a flow system constructed around a naturally fractured chalk core. Samples were analyzed for Ce and Br using ICP-MS, and colloid concentrations were determined using spectrophotographic analysis. Breakthrough curves comparing the rates of transportation of each tracer were obtained, allowing for comparison of

  11. Current oil and gas production from North American Upper Cretaceous chalks

    USGS Publications Warehouse

    Scholle, Peter A.

    1977-01-01

    Production of oil and natural gas from North American chalks has increased significantly during the past five years, spurred by the prolific production from North Sea chalks, as well as by higher prices and improved production technology. Chalk reservoirs have been discovered in the Gulf Coast in the Austin Group, Saratoga and Annona Chalks, Ozan Formation, Selma Group, Monroe gas rock (an informal unit of Navarro age), and other Upper Cretaceous units. In the Western Interior, production has been obtained from the Cretaceous Niobrara and Greenhorn Formations. Significant, though subcommercial, discoveries of natural gas and gas condensate also have been made in the Upper Cretaceous Wyandot Formation on the Scotian Shelf of eastern Canada. All North American chalk units share a similar depositional and diagenetic history. The chalks consist primarily of whole and fragmented coccoliths with subordinate planktonic and benthonic Foraminifera, inoceramid prisms, oysters, and other skeletal grains. Most have between 10 and 35 percent HCl-insoluble residue, predominantly clay. Deposition was principally below wave base in tens to hundreds of meters of water. The diagenetic history of a chalk is critical in determining its reservoir potential. All chalk has a stable composition (low-Mg calcite) and very high primary porosity. With subsequent burial, mechanical and chemical (solution-transfer) compaction can reduce or completely eliminate pore space. The degree of loss of primary porosity in chalk sections is normally a direct function of the maximum depth to which it has been buried. Pore-water chemistry, pore-fluid pressures, and tectonic stresses also influence rates of cementation. Oil or gas reservoirs of North American chalk fall into three main groups: 1. Areas with thin overburden and significant primary porosity retention (for example, Niobrara Formation of Kansas and eastern Colorado). 2. Areas with thicker overburden but considerable fracturing. Here primary

  12. Microbial secondary succession in a chronosequence of chalk grasslands.

    PubMed

    Kuramae, Eiko E; Gamper, Hannes A; Yergeau, Etienne; Piceno, Yvette M; Brodie, Eoin L; Desantis, Todd Z; Andersen, Gary L; van Veen, Johannes A; Kowalchuk, George A

    2010-05-01

    Although secondary succession has been studied extensively, we have little knowledge of the succession of soil-borne microbial communities. In this study, we therefore examined the structures of the microbial communities across two separate chronosequences of chalk grasslands in Limburg, the Netherlands, which are at different stages of secondary succession after being abandoned for between 17 and >66 years. Arable fields were also included in the investigation as non-abandoned references. Changes in the soil-borne microbial communities, as determined by phylogenetic microarray and quantitative PCR methodologies, were correlated with the prevailing environmental conditions related to vegetation and soil biochemistry. We observed clear patterns of microbial secondary succession related to soil age, pH and phosphate status, as exemplified by the overrepresentation of Verrucomicrobia, Acidobacteria, Gemmatimonadetes, and alpha-, delta- and epsilon-Proteobacteria at late successional stages. Moreover, effects of secondary succession versus changes in soil pH could be resolved, with pH significantly altering the trajectory of microbial succession.

  13. Effects of the restoration mortar on chalk stone buildings

    NASA Astrophysics Data System (ADS)

    Ion, R. M.; Teodorescu, S.; Ştirbescu, R. M.; Dulamă, I. D.; Şuică-Bunghez, I. R.; Bucurică, I. A.; Fierăscu, R. C.; Fierscu, I.; Ion, M. L.

    2016-06-01

    The monument buildings as components of cultural heritage are exposed to degradation of surfaces and chemical and mechanical degradation, often associated to soiling and irreversible deterioration of the building. In many conservative and restorative works, a cement-based mortar was used without knowing all the adverse effects of this material on the building. This paper deals with the study of the effects of natural cement used in restorative works in the particular case of the Basarabi-Murfatlar Churches Ensemble. Cement-based materials exposed to sulfate present in the chalk stone - gypsum (CaSO4.2H2O), can induce signs of deterioration, due to ettringite ([Ca3Al (OH)612H2O]2(SO4)32H2O) or thaumasite (Ca3[Si(OH)612H2O](CO3)SO4) formation. These phases contribute to strain within the material, inducing expansion, strength loss, spalling and severe degradation. Several combined techniques (XRD, EDXRF, ICP-AES, SEM, EDS, sulphates content, FT-IR and Raman analysis were carried out to put into evidence the effects of them on the building walls.

  14. Characterization of the hydraulic properties of fractures in chalk.

    PubMed

    Nativ, Ronit; Adar, Eilon; Assaf, Lior; Nygaard, Erik

    2003-01-01

    The fracture systems intersecting Eocene chalk formations in the Negev desert, Israel, and their hydraulic properties were characterized using a variety of geologic and hydrologic techniques. These included identification of the prevailing directions of fracture systems in outcrops, in cores retrieved from inclined coreholes, in coreholes using video logs, and in trenches. The orientation and inclination of these fracture systems were determined, and evidence of ground water flow on the fracture surfaces was described and ranked. Their hydraulic conductivity was determined through slug and pumping tests performed at discrete intervals. Temperature, electrical conductivity, caliper, gamma and heat-pulse logs were conducted in the same coreholes. The results from the logs, tests, and core descriptions were compared to identify reliable and cost-effective tools for investigating the hydraulic characteristics of fracture systems. We concluded that in the study area: (1) fracture mapping in outcrops and coreholes (including downhole video and caliper logs) must be supplemented by hydraulic testing of the mapped fracture sets in the coreholes; (2) inclined coreholes provide information regarding the orientation of the hydraulically active fracture systems that cannot be obtained from vertical boreholes; (3) hydraulic testing of unpacked holes provides a reasonable estimate of the maximum hydraulic conductivity; and (4) the hydraulic conductivity distribution with depth is log normal and all significant ground water flow takes place within the upper 25 m.

  15. Subaerial Chalk Cliff Failures on the English Channel Coast, Based on Field Data From Recent Collapses

    NASA Astrophysics Data System (ADS)

    DUPERRET, A.; MARTINEZ, A.; GENTER, A.; MORTIMORE, R. N.; WATREMEZ, P.

    2001-12-01

    The chalk cliffs along the English Channel coast are currently retreating at a mean rate of 0.5 m/year. However, the erosion is not constant over time, but occurs by catastrophic collapses. For the last three years, a minimum of 40 collapses have been observed along the French chalk coastline (120 km long) and about 10 collapses along the English chalk coastline (40 km long). The observed collapsed volumes are varying from 150 000 m3 (Beachy Head, UK) to a few m3, whereas the cliff heights are varying from 20 to 200m. Two kinds of scar extension have been observed on the cliff face: either the lower part only with few volumes involved, either the whole cliff height for the largest events. Two main cases of scar shape have been evidenced: (1) scar with a vertical upper part and a curved lower part with large striations and crushed chalk (Puys, France). The rupture process is an overall sliding process, with tearing of the upper part of the cliff and shearing in its lower part. The failure is mainly controlled by rain-fall and occurred by water pressure increase on impervious marl seams of the chalk (Duperret et al., in press, JCR). (2) scar with a regular and rectilinear profile, without any striation (Birling Gap, UK). The rupture propagates along pre-existing joint sets, parallel oriented to the cliff face. Locally, pre-existing large-scale transverse fractures may bound the lateral propagation of the scar. Where the scars extend all over the cliff height, the failure is mainly controlled by continental water infiltration. However the role of water through fractured chalk may differ according to the fracture pattern. Where the scars are restrained to the lower part of the cliff, the upward extension of the scars are bounded by lithological features of the chalk, as horizontal flint bands or stratification. In this case, the role of marine parameters, as wave impact at the toe of the cliff may be invoked as a significant triggering parameter contributing to failure

  16. Reactive transport modelling of groundwater chemistry in a chalk aquifer at the watershed scale

    NASA Astrophysics Data System (ADS)

    Mangeret, A.; De Windt, L.; Crançon, P.

    2012-09-01

    This study investigates thermodynamics and kinetics of water-rock interactions in a carbonate aquifer at the watershed scale. A reactive transport model is applied to the unconfined chalk aquifer of the Champagne Mounts (France), by considering both the chalk matrix and the interconnected fracture network. Major element concentrations and main chemical parameters calculated in groundwater and their evolution along flow lines are in fair agreement with field data. A relative homogeneity of the aquifer baseline chemistry is rapidly reached in terms of pH, alkalinity and Ca concentration since calcite equilibrium is achieved over the first metres of the vadose zone. However, incongruent chalk dissolution slowly releases Ba, Mg and Sr in groundwater. Introducing dilution effect by rainwater infiltration and a local occurrence of dolomite improves the agreement between modelling and field data. The dissolution of illite and opal-CT, controlling K and SiO2 concentrations in the model, can be approximately tackled by classical kinetic rate laws, but not the incongruent chalk dissolution. An apparent kinetic rate has therefore been fitted on field data by inverse modelling: 1.5 × 10- 5 molchalk L - 1water year - 1. Sensitivity analysis indicates that the CO2 partial pressure of the unsaturated zone is a critical parameter for modelling the baseline chemistry over the whole chalk aquifer.

  17. Improving UK Chalk hydrometeorology across spatial scales using a small hydrometeorological network

    NASA Astrophysics Data System (ADS)

    Rosolem, Rafael; Iwema, Joost; Rahman, Mostaquimur; Desilets, Darin; Koltermann da Silva, Juliana

    2016-04-01

    Chalk in the UK acts as a primary aquifer providing up to 80% of the public water supply locally. Chalk outcrops are located over most of southern and eastern England. Despite its importance, the characterization of Chalk in hydrometeorological models is still very limited. There is a need for a comprehensive and coherent integration of observations and modeling efforts across spatial scales for better understanding Chalk hydrometeorology. Here we introduce the "A MUlti-scale Soil moisture-Evapotranspiration Dynamics" (AMUSED) project. AMUSED goal is to better identify the key dominant processes controlling changes in soil moisture and surface fluxes (e.g., evapotranspiration) across spatial scales by combining ground-based observations with hydrometeorological models and satellite remote sensing products. The AMUSED observational platform consists of three sites located in Upper Chalk region of the Lambourn Catchment located in southern England covering approximately 2 square-km characterized by distinct combinations of soil and vegetation types. The network includes standard meteorological measurements, an eddy covariance system for turbulent fluxes and cosmic-ray neutron sensors for integrated soil moisture estimates at intermediate scales. Here we present our initial results from our three sites.

  18. Dynamic depositional and early diagenetic processes in a deep-water shelf setting, upper cretaceous Austin Chalk, North Texas

    SciTech Connect

    Hovorka, S.D.; Nance, H.S.

    1994-12-31

    The Austin Chalk of north Texas was deposited on a deep-water shelf north of the Sea Marcos Platform during a worldwide Coniacian and Santonian sea-level highstand. Transgressive (lowermost lower Austin Chalk), highstand (uppermost lower Austin Chalk), and regressive (middle and upper Austin Chalk) phases of cyclic chalk and marl sedimentation are recognized in excavations and tunnels created in Ellis County for the Superconducting Super Collider provide new evidence of sediment transport during Austin Chalk deposition. During transgression, bottom currents syndepositionally reworked nannoplankton oozes, incising channels as much as 120 ft across and 8 ft deep. Weakly burrowed channel fills having preservation of fine lamination document rapid infilling. Channel fills are composed of pyritized and carbonized wood and Inoceramus lag deposits, pellets, echinoderm fragments, and globigerinid grainstones, and coccolith ooze. During maximum highstand, bottom reworking was suppressed. Detrital content of highstand marls is low (>20 percent); organic content is high (1.4 to 3.5 percent). Coccolith preservation is excellent because of minimal diagenetic alteration. Regression is marked by resumed channel cutting and storm-bed winnowing in the middle and upper Austin Chalk. Suppressed resistivity log response and recessive weathering characteristics of the middle Austin Chalk are not primarily related to depositional environment but rather to increased input of volcanic ash during the accumulation of this interval. Early stabilization of ash produced clay-coated microfabrics in sediments that are otherwise similar to the transgressive deposits.

  19. Persistent and emerging micro-organic contaminants in Chalk groundwater of England and France.

    PubMed

    Lapworth, D J; Baran, N; Stuart, M E; Manamsa, K; Talbot, J

    2015-08-01

    The Chalk aquifer of Northern Europe is an internationally important source of drinking water and sustains baseflow for surface water ecosystems. The areal distribution of microorganic (MO) contaminants, particularly non-regulated emerging MOs, in this aquifer is poorly understood. This study presents results from a reconnaissance survey of MOs in Chalk groundwater, including pharmaceuticals, personal care products and pesticides and their transformation products, conducted across the major Chalk aquifers of England and France. Data from a total of 345 sites collected during 2011 were included in this study to provide a representative baseline assessment of MO occurrence in groundwater. A suite of 42 MOs were analysed for at each site including industrial compounds (n=16), pesticides (n=14) and pharmaceuticals, personal care and lifestyle products (n=12). Occurrence data is evaluated in relation to land use, aquifer exposure, well depth and depth to groundwater to provide an understanding of vulnerable groundwater settings.

  20. Chalk-Ex: An Ocean Optics Manipulation Experiment on the Fate of Calcite Particles

    NASA Astrophysics Data System (ADS)

    Balch, W. M.; Plueddemann, A. J.; Pilskaln, C. H.; Dam, H. G.; McManus, G. B.; Goes, J. I.

    2002-12-01

    Large-scale manipulation experiments such as Iron-Ex have allowed the testing of fundamental hypotheses about the ocean, not easily approachable with typical bench-style experimentation. Manipulation experiments provide tremendous insight by integrating the entire biogeochemical system into the results; they arguably give some of the most valuable tests for today's complex numerical models, at relatively fine spatial scales. One poorly understood biogeochemical cycle is that of CaCO3. About one quarter of the earth's marine sediment is CaCO3, much of which is composed of small coccoliths. How these particles are transported to the sea floor is still an open question. In this talk, we will present an overview of experiments from November 2001 from Continental Shelf and Slope waters off the NE U.S., in which Cretaceous coccolith chalk was dispersed into a patch of about 1.5 km2 (dubbed "Chalk-Ex"). The chalk's extremely well-defined light scattering and stable isotope properties made it possible to monitor the patch evolution and examine the importance of physical processes (horizontal shear, vertical mixing), grazing (macro- and micro-zooplankton), aggregation, interactions with dissolved organic carbon and sinking (estimated with drifting sediment traps). Lagrangian drifters were used to follow the patch and an instrumented drifter was used to characterize T-S properties over several days. From a particle perspective, the power of Chalk-Ex was that it simplified particle turn-over calculations. That is, while most particle experiments must simultaneously quantify both the production and loss terms of the particles in question (often with limited statistical precision), in Chalk-Ex, the production term was known almost exactly, so that we could focus on subsequent loss terms. The process that appeared to be most important to the patch evolution was horizontal dispersion at the "injection density", driven by shear between the surface and the maximum injection depth

  1. Bringing mini-chalk talks to the bedside to enhance clinical teaching

    PubMed Central

    Pitt, Michael B.; Orlander, Jay D.

    2017-01-01

    ABSTRACT Chalk talks – where the teacher is equipped solely with a writing utensil and a writing surface – have been used for centuries, yet little has been written about strategies for their use in medical education. Structured education proximal to patient encounters (during rounds, at the bedside, or in between patients in clinic) maximizes the opportunities for clinical learning. This paper presents a strategy to bring mini-chalk talks (MCTs) to the bedside as a practical way to provide relevant clinical teaching by visually framing teachable moments. Grounded in adult learning theory, MCTs leverage teaching scripts to facilitate discussion, involve learners at multiple levels, and embrace the increased retention associated with visual aids. These authors provide specific recommendations for the design and implementation of MCT sessions including what topics work well, how to prepare, and how to involve and engage the learners. Abbreviations: ADHD: Attention Deficit Hyperactivity Disorder; MCT: Mini-chalk talks PMID:28178911

  2. Particle transport in unsaturated fractured chalk under arid conditions.

    PubMed

    Weisbrod, Noam; Dahan, Ofer; Adar, Eilon M

    2002-05-01

    A series of field and laboratory experiments were conducted to study the mechanisms of particle detachment and transport from fractures in vadose chalk. Experiments of intermittent flow events along fracture surfaces were carried out in the laboratory. In the field, water was percolated from land surface via a discrete fracture into a compartmental sampler installed inside a horizontal corehole located I m below the surface. The mass, size distribution, and composition of the particles drained from the fracture voids were examined along with flow rates and salt dissolution. Two boreholes penetrating the underlying saturated zone were sampled and analyzed for colloidal concentration and composition. Most of the particle and solute release at the drained effluents occurred during the first several hours of flow, but erratic pulses of particles were still observed after long periods of time. Most of the detached particles had a mean diameter of >2 microm, while the mobile colloidal phase in the groundwater had a mean diameter of approximately 1 microm. Mineralogical composition of the groundwater colloids and the particles detached from the upper vadose fracture were similar. Laboratory observations demonstrated the importance of the existence of a coating layer, made of weathered particles and salts, on particle detachment. The results of this study suggest that: (1) particle detachment causes flow-rate variability in the unsaturated fracture; (2) the mechanisms of particle detachment and salt dissolution within the fracture are linked: and (3) although most of the detached particles are large and likely to accumulate inside fractures, some colloidal particles also eroded from the fracture void and are likely to be transported to the groundwater.

  3. Factors controlling spatial and temporal patterns of multiple pesticide compounds in groundwater (Hesbaye chalk aquifer, Belgium).

    PubMed

    Hakoun, Vivien; Orban, Philippe; Dassargues, Alain; Brouyère, Serge

    2017-04-01

    Factors governing spatial and temporal patterns of pesticide compounds (pesticides and metabolites) concentrations in chalk aquifers remain unclear due to complex flow processes and multiple sources. To uncover which factors govern pesticide compound concentrations in a chalk aquifer, we develop a methodology based on time series analyses, uni- and multivariate statistics accounting for concentrations below detection limits. The methodology is applied to long records (1996-2013) of a restricted compound (bentazone), three banned compounds (atrazine, diuron and simazine) and two metabolites (deethylatrazine (DEA) and 2,6-dichlorobenzamide (BAM)) sampled in the Hesbaye chalk aquifer in Belgium. In the confined area, all compounds had non-detects fractions >80%. By contrast, maximum concentrations exceeded EU's drinking-water standard (100 ng L(-1)) in the unconfined area. This contrast confirms that recent recharge and polluted water did not reach the confined area, yet. Multivariate analyses based on variables representative of the hydrogeological setting revealed higher diuron and simazine concentrations in the southeast of the unconfined area, where urban activities dominate land use and where the aquifer lacks protection from a less permeable layer of hardened chalk. At individual sites, positive correlations (up to τ=0.48 for bentazone) between pesticide compound concentrations and multi-annual groundwater level fluctuations confirm occurrences of remobilization. A downward temporal trend of atrazine concentrations likely reflects decreasing use of this compound over the last 28 years. However, the lack of a break in concentrations time series and maximum concentrations of atrazine, simazine, DEA and BAM exceeding EU's standard post-ban years provide evidence of persistence. Contrasting upward trends in bentazone concentrations show that a time lag is required for restriction measures to be efficient. These results shed light on factors governing pesticide

  4. Chalk, What Chalk?

    ERIC Educational Resources Information Center

    Butler, Loren L.

    2004-01-01

    When it comes to technological wizardry in the classroom, interactive whiteboards stand on the cutting edge of the future. Students seem innately able to manipulate any type of computerized equipment, and, more important, they are highly motivated to engage in "techno-discovery." It is the duty of every educator to facilitate further discovery and…

  5. The surface reactivity of chalk (biogenic calcite) with hydrophilic and hydrophobic functional groups

    NASA Astrophysics Data System (ADS)

    Okhrimenko, D. V.; Dalby, K. N.; Skovbjerg, L. L.; Bovet, N.; Christensen, J. H.; Stipp, S. L. S.

    2014-03-01

    The surface properties of calcium carbonate minerals play an important role in a number of industrial and biological processes. Properties such as wettability and adsorption control liquid-solid interface behaviour and thus have a strong influence on processes such as biomineralisation, remediation of aquifers and oil recovery. We investigated how two model molecules of different polarity, namely water and ethanol, interact with reservoir and outcrop chalk samples and we compared their behaviour with that of pure, inorganically precipitated calcite. Thermodynamic quantities, such as the work of wetting, surface energy and isosteric adsorption enthalpy, were determined from vapour adsorption isotherms. The chalks were studied fresh and after extraction of organic residues that were originally present in these samples. The work of wetting correlates with the amount of organic matter present in the chalk samples but we observed a fundamental difference between the adsorption properties of chalk and pure, inorganically precipitated calcite toward the less polar, ethanol molecule. Further analysis of the chemical composition of the organic matter extracted from the chalk samples was made by gas chromatography (GC-MS). Monitoring surface composition by X-ray photoelectron spectroscopy (XPS) before and after extraction of the organic material, and with atomic force microscopy (AFM), showed that nanometer sized clay crystals observed on the chalk particle surfaces could be an important part of the reason for the differences. Removal of the extractable portion of the hydrocarbons liberates adsorption sites that have different wetting properties than the rest of the chalk and these have an energy distribution that is similar to clays. Thus, the results exemplify the complexity of biogenic calcite adsorption behaviour and demonstrate that chalk wetting in drinking water aquifers as well as oil reservoirs is controlled partly by the nanoparticles of clay that have grown on the

  6. Authigenic kaolinite and associated pyrite in chalk of the Cretaceous Niobrara Formation, Eastern Colorado.

    USGS Publications Warehouse

    Pollastro, R.M.

    1981-01-01

    Cores from the Smoky Hill Chalk Member of the Cretaceous Niobrara Formation have several zones containing authigenic kaolinite as spherical, moldic, polycrystalline aggregates that occur within single or multichambered foraminiferal tests and are commonly associated with framboidal pyrite. Such kaolinite is inferred to result from volcanic ash deposited during chalk sedimentation. Shortly after burial, a colloidal aluminous gel or solution formed from the unstable ash and moved into organic-rich foraminiferal tests, where sulfate-reducing bacteria created a favorable microenvironment for the simultaneous crystallization of kaolinite and pyrite. -Author

  7. The Effect of Magnesium Carbonate (Chalk) on Geometric Entropy, Force, and Electromyography During Rock Climbing.

    PubMed

    Kilgas, Matthew A; Drum, Scott N; Jensen, Randall L; Phillips, Kevin C; Watts, Phillip B

    2016-12-01

    Rock climbers believe chalk dries the hands of sweat and improves the static coefficient of friction between the hands and the surface of the rock. The purpose of this study was to assess whether chalk affects geometric entropy or muscular activity during rock climbing. Nineteen experienced recreational rock climbers (13 males, 6 females; 173.5 ± 7.0 cm; 67.5 ± 3.4 kg) completed 2 climbing trails with and without chalk. The body position of the climber and muscular activity of the finger flexors was recorded throughout the trial. Following the movement sequence participants hung from a standard climbing hold until they slipped from the climbing structure, while the coefficient of friction and the ratio of the vertical forces on the hands and feet were determined. Although there were no differences in the coefficient of friction (P = .748), geometric entropy (P = .359), the ratio of the vertical forces between the hands and feet (P = .570), or muscular activity (P = .968), participants were able to hang longer after the use of chalk 62.9 ± 36.7 s and 49.3 ± 25.2 s (P = .046). This is advantageous because it may allow for prolonged rests, and more time to plan the next series of climbing moves.

  8. Effective-stress-law behavior of Austin chalk rocks for deformation and fracture conductivity

    SciTech Connect

    Warpinski, N.R.; Teufel, L.W.

    1994-08-01

    Austin chalk core has been tested to determine the effective law for deformation of the matrix material and the stress-sensitive conductivity of the natural fractures. For deformation behavior, two samples provided data on the variations of the poroelastic parameter, {alpha}, for Austin chalk, giving values around 0.4. The effective-stress-law behavior of a Saratoga limestone sample was also measured for the purpose of obtaining a comparison with a somewhat more porous carbonate rock. {alpha} for this rock was found to be near 0.9. The low {alpha} for the Austin chalk suggests that stresses in the reservoir, or around the wellbore, will not change much with changes in pore pressure, as the contribution of the fluid pressure is small. Three natural fractures from the Austin chalk were tested, but two of the fractures were very tight and probably do not contribute much to production. The third sample was highly conductive and showed some stress sensitivity with a factor of three reduction in conductivity over a net stress increase of 3000 psi. Natural fractures also showed a propensity for permanent damage when net stressed exceeded about 3000 psi. This damage was irreversible and significantly affected conductivity. {alpha} was difficult to determine and most tests were inconclusive, although the results from one sample suggested that {alpha} was near unity.

  9. Maastrichtian ammonites chiefly from the Prairie Bluff Chalk in Alabama and Mississippi

    USGS Publications Warehouse

    Cobban, W.A.; Kennedy, W.J.

    1995-01-01

    The Prairie Bluff Chalk of Alabama and Mississippi yields a diverse ammonite fauna of Maastrichtian age. Twenty-eight species, of which three are new, are recorded. The bulk of the fauna can be referred to a Discoscaphites conradi assemblage zone, but some elements in the fauna are significantly older. -Authors

  10. 24. ARAIII Reactor building ARA608 interior. Camera facing south. Chalk ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. ARA-III Reactor building ARA-608 interior. Camera facing south. Chalk marks on wall indicate presence or absence of spot contamination. Ineel photo no. 3-2. - Idaho National Engineering Laboratory, Army Reactors Experimental Area, Scoville, Butte County, ID

  11. Reservoir fracture mapping using microearthquakes: Austin chalk, Giddings field, TX and 76 field, Clinton Co., KY

    SciTech Connect

    Phillips, W.S.; Rutledge, J.T.; Fairbanks, T.D.

    1996-12-31

    Patterns of microearthquakes detected downhole defined fracture orientation and extent in the Austin chalk, Giddings field, TX and the 76 field, Clinton Co., KY. We collected over 480 and 770 microearthquakes during hydraulic stimulation at two sites in the Austin chalk, and over 3200 during primary production in Clinton Co. Data were of high enough quality that 20%, 31% and 53% of the events could be located, respectively. Reflected waves constrained microearthquakes to the stimulated depths at the base of the Austin chalk. In plan view, microearthquakes defined elongate fracture zones extending from the stimulation wells parallel to the regional fracture trend. However, widths of the stimulated zones differed by a factor of live between the two Austin chalk sites, indicating a large difference in the population of ancillary fractures. Post-stimulation production was much higher from the wider zone. At Clinton Co., microearthquakes defined low-angle, reverse-fault fracture zones above and below a producing zone. Associations with depleted production intervals indicated the mapped fractures had been previously drained. Drilling showed that the fractures currently contain brine. The seismic behavior was consistent with poroelastic models that predicted slight increases in compressive stress above and below the drained volume.

  12. Reservoir fracture mapping using microearthquakes: Austin chalk, Giddings field, TX and 76 field, Clinton Co., KY

    SciTech Connect

    Phillips, W.S.; Rutledge, J.T.; Gardner, T.L.; Fairbanks, T.D.; Miller, M.E.; Schuessler, B.K.

    1996-11-01

    Patterns of microearthquakes detected downhole defined fracture orientation and extent in the Austin chalk, Giddings field, TX and the 76 field, Clinton Co., KY. We collected over 480 and 770 microearthquakes during hydraulic stimulation at two sites in the Austin chalk, and over 3200 during primary production in Clinton Co. Data were of high enough quality that 20%, 31% and 53% of the events could be located, respectively. Reflected waves constrained microearthquakes to the stimulated depths at the base of the Austin chalk. In plan view, microearthquakes defined elongate fracture zones extending from the stimulation wells parallel to the regional fracture trend. However, widths of the stimulated zones differed by a factor of five between the two Austin chalk sites, indicating a large difference in the population of ancillary fractures. Post-stimulation production was much higher from the wider zone. At Clinton Co., microearthquakes defined low-angle, reverse-fault fracture zones above and below a producing zone. Associations with depleted production intervals indicated the mapped fractures had been previously drained. Drilling showed that the fractures currently contain brine. The seismic behavior was consistent with poroelastic models that predicted slight increases in compressive stress above and below the drained volume.

  13. Probing the intrinsically oil-wet surfaces of pores in North Sea chalk at subpore resolution

    PubMed Central

    Hassenkam, T.; Skovbjerg, L. L.; Stipp, S. L. S.

    2009-01-01

    Pore surface properties control oil recovery. This is especially true for chalk reservoirs, where pores are particularly small. Wettability, the tendency for a surface to cover itself with fluid, is traditionally defined by the angle a droplet makes with a surface, but this macroscopic definition is meaningless when the particles are smaller than even the smallest droplet. Understanding surface wetting, at the pore scale, will provide clues for more effective oil recovery. We used a special mode of atomic force microscopy and a hydrophobic tip to collect matrices of 10,000 force curves over 5- × 5-μm2 areas on internal pore surfaces and constructed maps of topography, adhesion, and elasticity. We investigated chalk samples from a water-bearing formation in the Danish North Sea oil fields that had never seen oil. Wettability and elasticity were inhomogeneous over scales of 10s of nanometers, smaller than individual chalk particles. Some areas were soft and hydrophobic, whereas others showed no correlation between hardness and adhesion. We conclude that the macroscopic parameter, “wetting,” averages the nanoscopic behavior along fluid pathways, and “mixed-wet” samples have patches with vastly different properties. Development of reservoir hydrophobicity has been attributed to infiltrating oil, but these new results prove that wettability and elasticity are inherent properties of chalk. Their variability, even on single particles, must result from material originally present during sedimentation or material sorbed from the pore fluid some time later. PMID:19321418

  14. Ichnology and paleosubstrates of Austin Chalk (Cretaceous) outcrops: Southern Dallas and Ellis Counties, Texas

    SciTech Connect

    Dawson, W.C. ); Reaser, D.F. )

    1991-03-01

    Ichnofossils are abundant in outcrops of the Austin Chalk near Waxahachie, Texas (designated site of the Super-Conducting Super Collider). The abundance and diversity of ichnofossils in Austin strata contrast with the paucity of other macrofossils, except large inoceramids. The lower Austin Chalk (Coniacian) disconformably overlies the Eagle Ford Shale (Turonian). Planolites, Thalassinoides, and Chondrites are conspicuous in the lower Austin. Some lower Austin strata contain well-preserved burrows having menicus fillings. However, most lower Austin ichnofossils are poorly preserved and have compacted. The middle Austin Marl and upper Austin Chalk (Santonain) contain Planolites, Chondrites, Thalassinoides, and Pseudobilobites. Several thin, intensely burrowed, Fe-stained, horizons within the middle Austin represent omission surfaces having postomission Thalassinoides. The upper Austin disconformably underlies the Taylor Marl (Campanian). The Austin-Taylor contact is a Rhizocorallium-infested omission surface overlain by a condensed bed of phosphatic and pyritic bioclasts. Upper Austin occurrences of Rhizocorallium and Pseudobilobites are unique for North American Cretaceous chalks. Based on cross-cutting relationships and differences in morphology, diameter, and burrow-filling sediments, numerous ichnospecies of Thalassinoides are discernable throughout the Austin. Variations in preservation quality exhibited by successive generations of ichnofossils record progressive changes in substrate consistency. Earliest formed burrows have diffuse outlines representing an initial thixotropic (softground) Austin substrate. Subsequent generations of burrows have more distinct outlines recording a gradual increase in substrate firmness. Paleo-firmgrounds are common in Austin outcrops; evidence of hardgrounds is lacking. The Thalassinoides-dominated Austin ichnoassemblage represents an inner shelf paleoenvironment.

  15. Variation of Cohesion and Friction Angle With Temperature In High Porosity Chalk

    NASA Astrophysics Data System (ADS)

    Madland, M. V.; Vasshus, L.; Risnes, R.

    During the last 20 years, mechanical behaviour of porous chalk has been extensively studied in order to understand the problems concerning well instability, compaction and subsidence of North Sea chalk reservoirs. At the Ekofisk field the reservoir temperature is around 1300C and any effects of such temperatures could be quite significant. The temperature effects on the mechanical properties of the reservoir rocks have however received limited attention. So far few studies have been carried out and the results point in different directions. The objective of the present project is to investigate how high temperatures affect the different mechanical parameters of chalks. The work is a part of an ongoing PhD programme. For high porosity chalks, it has been shown (Risnes et al 2000) that the Mohr circle corresponding to the Brazilian test results fits very closely to the Mohr Coulomb line derived from conventional compressive test data. This fact makes the easily performed Brazilian test useful for estimation of the chalk cohesion. Combined with uniaxial compressive tests, estimates for friction angle may also be obtained. The chalks used in this study were high porosity outcrop chalks, which have similar mechanical properties as reservoir chalks. Several series of Brazilian, uniaxial ­and triaxial compressive tests have been performed at both ambient ­and reservoir temperature. Both water and glycol was used as the saturating fluid and in addition some test series of dry samples were performed. Glycol is fully miscible with water and this property assures no capillary effects if some water should remain in the chalk before saturation Cohesion and friction angle were determined for each series at varying temperatures and the results can be summarized as follows: 1.Tests with water saturated chalk show that the cohesion decreases with around 20 % when the temperature is increased from 200C to 1300C. The friction angle seems to be less affected but increases slightly

  16. Full-waveform Inversion of Crosshole GPR Data Collected in Strongly Heterogeneous Chalk: Challenges and Pitfalls

    NASA Astrophysics Data System (ADS)

    Keskinen, Johanna; Looms, Majken C.; Nielsen, Lars; Klotzsche, Anja; van der Kruk, Jan; Moreau, Julien; Stemmerik, Lars; Holliger, Klaus

    2015-04-01

    Chalk is an important reservoir rock for hydrocarbons and for groundwater resources for many major cities. Therefore, this rock type has been extensively investigated using both geological and geophysical methods. Many applications of crosshole GPR tomography rely on the ray approximation and corresponding inversions of first break traveltimes and/or maximum first-cycle amplitudes. Due to the inherent limitations associated with such approaches, the resulting models tend to be overly smooth and cannot adequately capture the small-scale heterogeneities. In contrast, the full-waveform inversion uses all the information contained in the data and is able to provide significantly improved images. Here, we apply full-waveform inversion to crosshole GPR data to image strong heterogeneity of the chalk related to changes in lithology and porosity. We have collected a crosshole tomography dataset in an old chalk quarry in Eastern Denmark. Based on core data (including plug samples and televiewer logging data) collected in our four ~15-m-deep boreholes and results from previous related studies, it is apparent that the studied chalk is strongly heterogeneous. The upper ~7 m consist of variable coarse-grained chalk layers with numerous flint nodules. The lower half of the studied section appears to be finer-grained and contains less flint. However, still significant porosity variations are also detected in the lower half. In general, the water-saturated (watertable depth ~2 m) chalk is characterized by high porosities, and thus low velocities and high attenuation, while the flint is essentially non-porous and has correspondingly high velocities and low attenuation. Together these characteristics form a strongly heterogeneous medium, which is challenging for the full-waveform inversion to recover. Here, we address the importance of (i) adequate starting models, both in terms of the dielectric permittivity and the electrical conductivity, (ii) the estimation of the source wavelet

  17. Occurrence of oil in the Austin Chalk at Van field, Van Zandt County, Texas: A unique geologic setting

    SciTech Connect

    Lowe, J.T.; Carrington, D.B. )

    1990-09-01

    The Austin Chalk is buried to a depth of only 2,100-2,500 ft and has retained primary microporosity unlike the typical deep fractured chalk reservoirs. The Van structure is a complexly faulted domal anticline created by salt intrusion and is approximately 2,000 ft higher than surrounding structures in the area. A major northwest-dipping fault acts as the primary trapping mechanism. The field has produced 0.5 billion BO from thick Woodbine sands since its discovery in 1929. Occurrence of oil in the Austin Chalk has been known since the field discovery, but prior completions were low rate oil producers. Recent development of a large fracture stimulation technique has resulted in increased production rates of up to 300 BOPD. The Austin Chalk reservoir limits were determined by isopaching feet of minimum productive resistivity having porosity above a cutoff value. The resistivity/porosity isopach showed a direct correlation between Austin Chalk productivity and the Austin Chalk structure and faulting pattern. Structural evidence along with oil typing indicate that the oil in the Austin Chalk has migrated upward along fault planes and through fault juxtaposition from the Woodbine sands 200 ft below the Austin Chalk. Thin-section and scanning electron microscopy work performed on conventional cores showed that the Van Austin Chalk formation is a very fine grained limestone composed primarily of coccoliths. Various amounts of detrital illite clay are present in the coccolith matrix. All effective porosity is micro-intergranular and ranges from 15 to 35%. Based on the core analyses, the main porosity reducing agent and therefore control on reservoir quality is the amount of detrital clay present filling the micropores. Permeability is very low with values ranging from 0.01 to 1.5 md. There is no evidence of significant natural fractures in the core. Artificial fractures are therefore required to create the permeability needed to sustain commercial production rates.

  18. Laboratory measurements of the electrokinetic and electrochemical potential in chalk, with application to monitoring of saline intrusion in the UK chalk aquifer

    NASA Astrophysics Data System (ADS)

    MacAllister, D.; Jackson, M.; Butler, A. P.; Vinogradov, J.

    2012-12-01

    Saline intrusion is a global phenomenon affecting the availability of freshwater in coastal aquifers. The aim of this work is to investigate whether measurements of spontaneous potential (SP) can be used to monitor the intrusion of seawater into coastal aquifers, with specific application to the chalk aquifer near Brighton on the south coast of the UK. SP arises to maintain electrical neutrality when a separation of charge occurs due to gradients in pressure (electrokinetic or streaming potential), concentration (electrochemical potential) and temperature (thermoelectric potential). Concentration gradients are a characteristic feature of saline intrusion and may give rise to a measureable electrochemical potential (EC). In addition the electrokinetic potential (EK) will arise during abstraction and up-coning of the saline front. The intruding saline front could therefore be detected and monitored continuously, with SP measurements in boreholes and at the surface providing dense monitoring in space and time. To determine the likely magnitude of EK and EC signals during saline intrusion into the chalk aquifer, we measured EK and EC potentials in samples of Seaford chalk saturated with (i) natural, potable groundwater from the aquifer and (ii) seawater sampled from the English Channel. The EK coupling coefficient, which relates the gradient in voltage to the gradient in water pressure when the total current is zero, was found to be -60 mV/MPa in samples saturated with groundwater. In seawater saturated samples it was found to be only -1 mV/MPa. This result agrees with earlier work suggesting the EK potential is suppressed in high salinity environments due to a compressed electrical double layer. The EK coupling coefficient was negative in both cases, suggesting that the surface charge of Seaford chalk is negative when in contact with groundwater and seawater. The electrochemical experiments involved establishing a concentration gradient across the chalk samples

  19. In-Situ Monitoring Of Nitrate Fluxes Through Unsaturated Zone In Chalk Aquifer

    NASA Astrophysics Data System (ADS)

    West, L. J.; Keim, D. M.; Odling, N. E.

    2013-12-01

    Diffuse source nitrate leaching from agricultural land threatens groundwater quality worldwide. In the United Kingdom the source of up to 70% of nitrate found in surface and groundwater is thought to have been leached from agricultural land. Rising concentrations approaching or exceeding the maximum permissible concentration level of 11.3 mg/l NO3-N (EC Drinking Water Directive) have been observed in UK catchments on the Cretaceous Chalk in recent decades. Prediction of future nitrate concentration trends in chalk aquifers is desirable for groundwater abstraction management, but is particularly challenging due to their complex dual porosity nature. Contaminants such as nitrate are either rapidly moved through the system via preferential fracture pathways or more slowly through the porous matrix. We report in-situ nitrate monitoring within the top 1 m of the soil zone and within the deeper chalk unsaturated zone at depths between 30 and 45 m carried out over an entire hydrological year. Observed nitrate concentrations exceeded natural baseline concentration of NO3-N expected in the Cretaceous Chalk aquifer of northern England by nearly four times and were nearly double the legislated maximum permissible drinking water concentration. Soil zone nitrate monitoring (up to 1 m depth) indicated a strong relationship between NO3-N concentration and land management, annual cropping and hydrological cycles. Annual variation in NO3-N concentration were smaller in water from the deeper unsaturated zone (at 30 - 45 m depth) than in the soil zone, i.e. fluctuations are smoothed by travel through the chalk unsaturated zone. However, observations in the deep unsaturated zone indicate water flow is focused in specific fractures or conduits, so contaminants from the surface will rapidly reach the water table, even through thick unsaturated zones in chalk. Moreover, the low permeability of the matrix coupled with fracture flow can result in an accumulation of NO3-N in the unsaturated

  20. NMR response of non-reservoir fluids in sandstone and chalk.

    PubMed

    van der Zwaag, C H; Stallmach, F; Skjetne, T; Veliyulin, E

    2001-01-01

    Transverse (T2) NMR relaxation time at 2 MHz proton resonance frequency was measured on core plug samples from two different lithologies, sandstone and chalk, before and after exposure to selected drilling fluids. The results show that NMR signal response was significantly altered after displacing 50% of the original pore fluids, crude oil and water, by drilling fluid filtrate. Relaxation spectra of the rock samples invaded by water-based filtrate shift to significantly shorter T2-values. This shift yields an underestimation of the free-fluid volumes when selecting cut-off values of 33 ms and 100 ms for sandstone and chalk, respectively. In opposite, rock samples affected by oil-based filtrate respond with a signal indicating significantly larger free-fluid volumes than present before exposure. NMR-permeability calculated based on the Timur-Coates Free Fluid model altered in some cases by one order of magnitude.

  1. Bringing mini-chalk talks to the bedside to enhance clinical teaching.

    PubMed

    Pitt, Michael B; Orlander, Jay D

    2017-01-01

    Chalk talks - where the teacher is equipped solely with a writing utensil and a writing surface - have been used for centuries, yet little has been written about strategies for their use in medical education. Structured education proximal to patient encounters (during rounds, at the bedside, or in between patients in clinic) maximizes the opportunities for clinical learning. This paper presents a strategy to bring mini-chalk talks (MCTs) to the bedside as a practical way to provide relevant clinical teaching by visually framing teachable moments. Grounded in adult learning theory, MCTs leverage teaching scripts to facilitate discussion, involve learners at multiple levels, and embrace the increased retention associated with visual aids. These authors provide specific recommendations for the design and implementation of MCT sessions including what topics work well, how to prepare, and how to involve and engage the learners.

  2. Results of blue crab studies at Chalk Point. Final report 1978-1979

    SciTech Connect

    Souza, P.A.; Polgar, T.T.; Miller, R.E.; Holland, A.F.

    1980-11-01

    This report summarizes the findings of two years of blue crab tagging studies conducted in the Patuxent estuary near the Chalk Point power plant. This report is organized in the following manner: An introduction and objectives section defines the objectives of the blue crab study, discusses the modes of interaction between blue crabs and power plant operations, and discusses the life history characteristics of blue crabs. A study methods section provides detailed information on tagging and capture operations and on analysis methods. A results section presents the major findings of the study. A discussion and conclusions section interprets and discusses major findings and defines the impacts of power plant operations at Chalk Point on blue crab populations in the Patuxent estuary. A list of references is included.

  3. Evaluation of auxiliary tempering pump effectiveness at Chalk Point Steam Electric Station

    SciTech Connect

    Wendling, L.C.; Holland, A.F.

    1989-08-01

    The effectiveness of auxiliary tempering pump operation at Chalk Point Steam Electric Station (SES) at reducing plant-induced mortality of aquatic biota was evaluated. Several Representative Important Species (RIS) and dominant benthic and zooplankton species were used in the evaluation as indicators of overall system-wide responses. Expected mortality with and without auxiliary pump operation was estimated using thermal tolerance data available from the scientific literature for blue crabs, white perch, striped bass, spot, Macoma balthica and Acartia tonsa. The evaluation led to the conclusion that the operation of auxiliary tempering pumps at Chalk Point SES increases plant-induced mortality of spot, white perch, striped bass, and zooplankton. Operation of the tempering pumps may reduce blue crab mortality slightly under certain circumstances, and Macoma balthica mortality is probably largely unaffected by their operation.

  4. Waveform analysis of crosshole GPR data collected in heterogeneous chalk deposits

    NASA Astrophysics Data System (ADS)

    Keskinen, Johanna; Nielsen, Lars; Looms, Majken C.; Moreau, Julien; Stemmerik, Lars; Klotzsche, Anja; van der Kruk, Jan; Holliger, Klaus

    2014-05-01

    Chalks are important reservoirs for groundwater production onshore Denmark and for hydrocarbons in the North Sea Basin. Therefore this rock type is studied extensively with geological and geophysical methods. Ground-penetrating radar (GPR) tomography is used to characterize fine-scale reservoir properties, e.g. subtle changes in porosity. We have conducted a range of high-resolution GPR crosshole experiments in Boesdal quarry in Eastern Denmark. The objective is to investigate the impact of fine-scale heterogeneity on reservoir properties in chalk. The studied chalk interval is c.15 m thick. It can be divided into two main units based on the traveltime analysis and interpretation of the cored material from the boreholes. The lower unit consists mainly of porous calcareous mudstone with occasional occurrences of flint nodules. The upper succession is c. 8 m thick and is fairly heterogeneous with multiple beds of wackestones and packstones with abundant flint nodules or bands. The heterogeneity of the upper layer is expressed by more complex waveforms than the lower unit. Pronounced attenuation of the transmitted wave fields is observed in the highly porous lower unit. Full-waveform inversion methods are highly dependent on the quality of the starting models (usually obtained from ray-based tomography), as well as on the assumptions made regarding the source signal. Adequate estimation of starting models and source waveform is, however, a challenging task for the strongly heterogeneous chalk material. We highlight the critical aspects regarding these tasks for the two contrasting layers. Furthermore we demonstrate how different starting models and assumptions regarding the source signal estimation affect the waveform inversion results.

  5. Intrinsic and Carrier Colloid-facilitated transport of lanthanides through discrete fractures in chalk

    NASA Astrophysics Data System (ADS)

    Weisbrod, N.; Tran, E. L.; Klein-BenDavid, O.; Teutsch, N.

    2015-12-01

    Geological disposal of high-level radioactive waste is the long term solution for the disposal of long lived radionuclides and spent fuel. However, some radionuclides might be released from these repositories into the subsurface as a result of leakage, which ultimately make their way into groundwater. Engineered bentonite barriers around nuclear waste repositories are generally considered sufficient to impede the transport of radionuclides from their source to the groundwater. However, colloidal-sized mobile bentonite particles ("carrier" colloids) originating from these barriers have come under investigation as a potential transport vector for radionuclides sorbed to them. As lanthanides are generally accepted to have the same chemical behaviors as their more toxic actinide counterparts, lanthanides are considered an acceptable substitute for research on radionuclide transportation. This study aims to evaluate the transport behaviors of lanthanides in colloid-facilitated transport through a fractured chalk matrix and under geochemical conditions representative the Negev desert, Israel. The migration of Ce both with and without colloidal particles was explored and compared to the migration of a conservative tracer (bromide) using a flow system constructed around a naturally fractured chalk core. Results suggest that mobility of Ce as a solute is negligible. In experiments conducted without bentonite colloids, the 1% of the Ce that was recovered migrated as "intrinsic" colloids in the form of carbonate precipitates. However, the total recovery of the Ce increased to 9% when it was injected into the core in the presence of bentonite colloids and 13% when both bentonite and precipitate colloids were injected. This indicates that lanthanides are essentially immobile in chalk as a solute but may be mobile as carbonate precipitates. Bentonite colloids, however, markedly increase the mobility of lanthanides through fractured chalk matrices.

  6. Development and maintenance of a telescoping debris flow fan in response to human-induced fan surface channelization, Chalk Creek Valley Natural Debris Flow Laboratory, Colorado, USA

    NASA Astrophysics Data System (ADS)

    Wasklewicz, T.; Scheinert, C.

    2016-01-01

    Channel change has been a constant theme throughout William L. Graf's research career. Graf's work has examined channel changes in the context of natural environmental fluctuations, but more often has focused on quantifying channel change in the context of anthropogenic modifications. Here, we consider how channelization of a debris flows along a bajada has perpetuated and sustained the development of 'telescoping' alluvial fan. Two-dimensional debris-flow modeling shows the importance of the deeply entrenched channelized flow in the development of a telescoping alluvial fan. GIS analyses of repeat (five different debris flows), high-resolution (5 cm) digital elevation models (DEMs) generated from repeat terrestrial laser scanning (TLS) data elucidate sediment and topographic dynamics of the new telescoping portion of the alluvial fan (the embryonic fan). Flow constriction from channelization helps to perpetuate debris-flow runout and to maintain the embryonic fan and telescoping nature of the alluvial fan complex. Embryonic fan development, in response to five debris flows, proceeds with a major portion of the flows depositing on the southern portion of the embryonic fan. The third through the fifth debris flows also begin to shift some deposition to the northern portion of the embryonic. The transfer of sediment from a higher portion of the embryonic fan to a lower portion continues currently on the embryonic fan. While channelized flow has been shown to be critical to the maintenance of the telescoping fan, the flow constriction has led to higher than background levels of sediment deposition in Chalk Creek, a tributary of the Arkansas River. A majority of the sediment from each debris flow is incorporated into Chalk Creek as opposed to being stored on the embryonic fan.

  7. Horizontal exploitation of the Upper Cretaceous Austin Chalk of south Texas

    SciTech Connect

    Borkowski, R.; Hand, L.; Dickerson, D.; Bird, S. )

    1990-05-01

    Horizontal drilling in the fractured Austin Chalk of south Texas has proven to be a viable technology for exploiting reserve opportunities in mature trends as well as in frontier areas. To date, the results of an interdisciplinary approach to the regional analysis of structure and stress regimes combined with studies of the depositional characteristics of the Austin Chalk and Eagleford Shale have been a success. Productive characteristics of the Austin Chalk indicate the influence of regional fractures on the preferential flow direction and partitioning in the Pearsall field area of the trend. Well bore orientation and inclination are designed such that multiple fracture swarms at several stratigraphic horizons are intersected with a single horizontal well bore. As a result of the greater frequency of fracture contacts with the well bore, there is a significant increase in the ultimate recovery of hydrocarbons in place. Conventional vertical drilling techniques are frequently ineffective at encountering these laterally partitioned fracture sets, resulting in lower volumes of recoverable hydrocarbons. Additionally, horizontal well bores may increase ultimate recovery of hydrocarbons by lowering the pressure gradient to the well bore and maximizing the reservoir energy.

  8. Fracture-network 3D characterization in a deformed chalk reservoir analogue -- the Laegerdorf case

    SciTech Connect

    Koestler, A.G.; Reksten, K.

    1995-09-01

    Quantitative descriptions of 3D fracture networks in terms of fracture characteristics and connectivity are necessary for reservoir evaluation, management, and EOR programs of fractured reservoirs. The author`s research has focused on an analogue to North Sea fractured chalk reservoirs that is excellently exposed near Laegerdorf, northwest Germany. An underlying salt diapir uplifted and deformed Upper Cretaceous chalk; the cement industry now exploits it. The fracture network in the production wall of the quarry was characterized and mapped at different scales, and 12 profiles of the 230-m wide and 35-m high production wall were investigated as the wall receded 25 m. In addition, three wells were drilled into the chalk volume. The wells were cored and the wellbores were imaged with both the resistivity formation micro scanner (FMS) and the sonic circumferential borehole image logger (CBIL). The large amount of fracture data was analyzed with respect to parameters, such as fracture density distribution, orientation, and length distribution, and in terms of the representativity and predictability of data sets collected from restricted rock volumes.

  9. Late Cretaceous (late Campanian-Maastrichtian) sea-surface temperature record of the Boreal Chalk Sea

    NASA Astrophysics Data System (ADS)

    Thibault, Nicolas; Harlou, Rikke; Schovsbo, Niels H.; Stemmerik, Lars; Surlyk, Finn

    2016-02-01

    The last 8 Myr of the Cretaceous greenhouse interval were characterized by a progressive global cooling with superimposed cool/warm fluctuations. The mechanisms responsible for these climatic fluctuations remain a source of debate that can only be resolved through multi-disciplinary studies and better time constraints. For the first time, we present a record of very high-resolution (ca. 4.5 kyr) sea-surface temperature (SST) changes from the Boreal epicontinental Chalk Sea (Stevns-1 core, Denmark), tied to an astronomical timescale of the late Campanian-Maastrichtian (74 to 66 Ma). Well-preserved bulk stable isotope trends and calcareous nannofossil palaeoecological patterns from the fully cored Stevns-1 borehole show marked changes in SSTs. These variations correlate with deep-water records of climate change from the tropical South Atlantic and Pacific oceans but differ greatly from the climate variations of the North Atlantic. We demonstrate that the onset and end of the early Maastrichtian cooling and of the large negative Campanian-Maastrichtian boundary carbon isotope excursion are coincident in the Chalk Sea. The direct link between SSTs and δ13C variations in the Chalk Sea reassesses long-term glacio-eustasy as the potential driver of carbon isotope and climatic variations in the Maastrichtian.

  10. Late Cretaceous (Late Campanian-Maastrichtian) sea surface temperature record of the Boreal Chalk Sea

    NASA Astrophysics Data System (ADS)

    Thibault, N.; Harlou, R.; Schovsbo, N. H.; Stemmerik, L.; Surlyk, F.

    2015-11-01

    The last 8 Myr of the Cretaceous greenhouse interval were characterized by a progressive global cooling with superimposed cool/warm fluctuations. The mechanisms responsible for these climatic fluctuations remain a source of debate that can only be resolved through multi-disciplinary studies and better time constraints. For the first time, we present a record of very high-resolution (ca. 4.5 kyr) sea-surface temperature (SST) changes from the Boreal epicontinental Chalk Sea (Stevns-1 core, Denmark), tied to an astronomical time scale of the late Campanian-Maastrichtian (74 to 66 Myr). Well-preserved bulk stable isotope trends and calcareous nannofossil palaeoecological patterns from the fully cored Stevns-1 borehole show marked changes in SSTs. These variations correlate with deep-water records of climate change from the tropical South Atlantic and Pacific oceans but differ greatly from the climate variations of the North Atlantic. We demonstrate that the onset and end of the early Maastrichtian cooling and of the large negative Campanian-Maastrichtian boundary carbon isotope excursion are coincident in the Chalk Sea. The direct link between SSTs and δ13C variations in the Chalk Sea reassesses long-term glacio-eustasy as the potential driver of carbon isotope and climatic variations in the Maastrichtian.

  11. Chemostratigraphy of Upper Cretaceous chalk sequences in Norwegian-Danish basin and North Sea Central Trough

    SciTech Connect

    Joergensen, N.O.

    1987-05-01

    Geochemical studies of subsurface sections and outcrops in the Upper Cretaceous chalk sequences from the Norwegian-Danish basin and the North Sea Central Trough have resulted in a detailed chemostratigraphy for these strata. The most applicable chemostratigraphic markers are based on the distribution of strontium, magnesium, manganese, the /sup 13/C//sup 12/C ratio, and the variations in the carbonate contents. It is demonstrated that the chemostratigraphic approach is valid at two levels: (1) a superior chemostratigraphy in which deep-sea cores from the Atlantic Ocean and sections from western Europe are correlated on the basis of significant geochemical anomalies and long-term variations most likely induced by oceanic geochemical cycles and sea level fluctuations; (2) a subordinate but detailed intrabasinal chemostratigraphic correlation which primarily reflects the physicochemical conditions in the depositional environment. The Upper Cretaceous chemostratigraphy established in the Danish area allows a detailed correlation between relatively continuous chalk sequences in the Norwegian-Danish basin and the rather condensed and hiati-influenced sections in the oil fields of the North Sea. The results emphasize the applicability of chemostratigraphy in the subsurface exploration for hydrocarbon reservoirs in chalk.

  12. Movement of leachate from beneath turkey litter sited over chalk in southern England.

    PubMed

    Gooddy, Daren C

    2002-01-01

    Farm waste stores are widespread in the UK, with many overlying the principal aquifer, the Chalk. The stores pose a threat to groundwater quality through the infiltration of high concentrations of nitrogen species and organic carbon together with pathogenic microbes. Two cored boreholes have been drilled into the unsaturated chalk to depths of 15 and 20 metres, respectively, through a site which has been used to store turkey litter for in excess of 20 years. Porewaters were extracted from the cores and analysed for a range of chemical elements. In addition, chalk core material was also taken for microbial examination. Both boreholes showed very high concentrations of nitrate-N (3000 mg/L), ammonia (5000 mg/L), organic carbon (3000 mg/L), and potassium (10,000 mg/L) in the top 5 metres of the profile. Below this depth concentrations declined dramatically. Highest concentrations were found in the borehole constructed in the middle of the site. The borehole constructed at the edge of the store showed much lower concentrations but did show a peak of nitrate around 10 metres below ground level. The apparent lack of movement beneath the centre of the store suggests the turkey litter is relatively impermeable and most leaching occurs where the covering of litter is thin or when the litter is annually cleared. If the leachate continues to migrate at this apparent rate, it will take more than 100 years to reach the water table.

  13. Oxidation and dispersion of HT in the environment: the August 1986 field experiment at Chalk River.

    PubMed

    Brown, R M; Ogram, G L; Spencer, F S

    1990-02-01

    The short-range environmental dispersion and oxidation of a release of tritiated hydrogen (HT) to the atmosphere has been studied in a field experiment. Emphasis was placed on the processes leading to the appearance of tritiated water (HTO) vapor in the atmosphere because HTO is much more radiotoxic than HT. The following conclusions were reached: No evidence was found for the rapid conversion of HT to HTO in the atmosphere; HTO observed in air, during and after the release, arose mainly from HT oxidation in the soil followed by emission of HTO; HT deposition velocities to soil ranged from 0.041 cm s-1 to 0.13 cm s-1, consistent with previous chamber measurements; the rate of HTO loss from soil, averaged over 21 d, was less than 1% h-1; and HTO concentrations in vegetation water initially increased with time after the release, then by 48 h decreased exponentially at a rate similar to soils.

  14. The influence of ionic forces on the effective diffusion coefficient in fractured, porous chalk.

    NASA Astrophysics Data System (ADS)

    Kremer, K.; Reichert, B.

    2005-12-01

    Solute transport in fractured, highly porous chalk significantly depends on the diffusive mass transfer of substances between the mobile water in the fracture and the immobile water of the rock matrix. Matrix diffusion is an important transport mechanism and a central factor for the retardation of solutes. Until now, simple estimation methods for the diffusive behavior of substances such as Archie's law can only be applied to single substances. Multi-tracer experiments proved a mutual influence on the diffusion of ionic solutes thus leading to significant deviations in respect to the theoretically estimated effective diffusion coefficient D_e. An increase of ionic forces in the aqueous phase is often accompanied by a decrease of D_e for cations and an increase for anions. However, groundwater contamination usually consists of several pollutants in different mixtures. Besides ionic forces, effects of channeling and transport of colloids can result in incorrectly estimated D_e values and, hence, high inaccuracy in the modeling of contaminant transport in fractured porous media. In the context of a current DFG-project, the impact of ionic forces on D_e as well as the interaction of the diffusion of ionic ground water solutes in fractured chalk of Denmark (Cretaceous, Sigerslev) and Israel (Eocene, Negev desert) will be quantified to develop a procedure for an improved estimation of D_e in dependence of the ionic activity. Consequently, the well established Archie's law for the prediction of diffusivities on the basis of the total porosities will be modified by an extension term a. So far series of single-tracer through-diffusion experiments have been performed with potassium bromide in six different concentrations to quantify the concentration dependence on the matrix diffusion as well as to examine the influence of the ionic strength on the effective diffusion coefficients of ionic solutes. The simultaneously injected neutral deuterium serves as a reference tracer

  15. Diagenesis of the Machar Field (British North Sea) chalk: Evidence for decoupling of diagenesis in fractures and the host rock

    SciTech Connect

    Maliva, R.G.; Dickson, J.A.D.; Smalley, P.C.; Oxtoby, N.H.

    1995-01-02

    The Chalk Group (Cretaceous/Tertiary) in the Machar Field (British North Sea) contains both fracture-filling and microcrystalline calcite cements. Modeling of fluid-rock interaction using data on light stable isotopes obtained by whole rock analyses and laser ablation analyses of calcite cements reveal that the fracture and matrix diagenetic systems were largely decoupled. The calcium and carbonate of the fracture-filling calcite cements were derived largely from the adjacent chalk matrix. The fracture diagenetic system had a high water-rock ratio, which maintained a relatively stable water {delta}{sup 18}O ratio during calcite dissolution and precipitation. The chalk matrix, on the contrary, had a low molar water-rock ratio during recrystallization, which resulted in increases in the pore-water {delta}{sup 18}O value during recrystallization at elevated temperatures. This evolution of the pore-water {delta}{sup 18}O value is manifested by highly variable cement {delta}{sup 18}O values. The present-day formation waters of the Machar Field have {sup 87}Sr/{sup 86}Sr ratios significantly higher than the whole rock and fracture-filling cement calcite values, evidence that the chemical composition of the formation waters is not representative of that of the pore waters during chalk recrystallization. Little diagenesis is therefore now occurring in the Machar Field. The diagenetic systems of the chalk matrix and fractures both had a high degree of openness with respect to carbon, because of the introduction of organically derived bicarbonate rather than advection of water through the chalk. The bulk of calcite cementation in fractures and the recrystallization and cementation of the chalk matrix occurred at temperatures in the 80--100 C range, at or just below the present-day reservoir temperature of 97 C.

  16. Effect of Calabash Chalk on the Histomorphology of the Gastro-Oesophageal Tract of Growing Wistar Rats

    PubMed Central

    Moses, B Ekong; Emma, E John; Christopher, C Mbadugha; Enobong I, Bassey; Theresa, B Ekanem

    2012-01-01

    Background: Calabash chalk is a naturally occurring mineral consumed by members of some Nigerian communities for pleasure and by pregnant women as a remedy for morning sickness. The consumption of this geophagic material motivated our interest on the effect of the chalk on the histomorphology of the gastro-oesophageal tract. Methods: Twenty-eight young Wistar rats, 4 weeks old, were divided into 4 groups of equal size. Group 1 animals served as controls and received 1 mL of distilled water. Groups 2, 3, and 4 received orally 1 mL of a Calabash chalk suspension containing 40 mg/mL for 14, 21, and 28 days, respectively. Upon completion of the treatments, the animals in groups 2, 3, and 4 were sacrificed on days 15, 22, and 29, respectively, and the control group animals were sacrificed on day 29. All animals were euthanised using chloroform anaesthesia. The oesophagus and the stomach of each animal were dissected out and routinely processed for histological studies. Results: There was oedema with haemorrhages in the mucosa of the stomach, and acanthosis, hyperkeratosis, and koilocytic changes were observed in the mucosa of the oesophagus of the groups treated with 40 mg/mL of Calabash chalk suspension. Conclusion: Calabash chalk caused histological changes to the stomach and the oesophagus that may lead to other pathophysiological conditions. PMID:22977372

  17. Caoxite-hydroxyapatite composition as consolidating material for the chalk stone from Basarabi-Murfatlar churches ensemble

    NASA Astrophysics Data System (ADS)

    Ion, Rodica-Mariana; Turcanu-Caruţiu, Daniela; Fierăscu, Radu-Claudiu; Fierăscu, Irina; Bunghez, Ioana-Raluca; Ion, Mihaela-Lucia; Teodorescu, Sofia; Vasilievici, Gabriel; Rădiţoiu, Valentin

    2015-12-01

    The development of new composition for surface conservation of some architectural monuments represents now an important research topic. The Basarabi-Murfatlar Ensemble, recognized as the first religious monument from mediaeval Dobrogea (Romania) (from 9th to 11th century), is one of the most impressive archaeological sites of Europe. This ensemble is built from amorphous calcium carbonate, very sensitive to humidity, frost, salts, etc. The aim of this paper is to test on chalk stone samples a new consolidant - hydroxyapatite (HAp) mixed with calcium oxalate trihydrate (caoxite) (COT). Some specific techniques for evaluation its impact on chalk stone surface are used, as follows: petrographical and physical-chemical techniques: SEM, OM, ICP-AES, TGA, FTIR and Raman spectroscopy, chromatic parameters changes, the accelerated weathering tests: heating, freeze-thaw, and their effects on porosity and capillary water uptake by the chalk surface. All these have been evaluated before and after treatment with COT-HAp, putting into evidence the effect of the new composition on the chalk stone surface. HAp induces COT stabilization, and their joint composition can bind weathered stone blocks providing a substantial reinforcement of chalk surface.

  18. Spatial heterogeneity of high-resolution Chalk groundwater geochemistry - Underground quarry at Saint Martin-le-Noeud, France

    NASA Astrophysics Data System (ADS)

    Barhoum, S.; Valdès, D.; Guérin, R.; Marlin, C.; Vitale, Q.; Benmamar, J.; Gombert, P.

    2014-11-01

    Chalk groundwater is an important aquifer resource in France because it accounts for a production of 12 million m3 y-1 with a large proportion reserved for drinking water. Processes occurring in the unsaturated zone (UZ) and the overlying superficial formations have a high impact on Chalk groundwater geochemistry and require better understanding. The study site is a former underground Chalk quarry located near Beauvais (France) that extends over 1200 m in length, at a depth ranging from 20 to 30 m. The water table intersects the cavity creating 15 underground “lake” that give access to the Chalk groundwater. Lakes geochemistry has been studied: water samples were collected in July 2013 and major ion concentrations were analyzed. UZ and clay-with-flints thickness above each lake were estimated qualitatively using an electromagnetic sensor (EM31) and Underground GPS. The results unexpectedly showed that groundwater quality varied widely in spatial terms for both allochthonous and autochthonous ions (e.g., HCO3- ranged from 2.03 to 4.43 meq L-1, NO3- ranged from 0.21 to 1.33 meq L-1). Principal component analysis indicated the impact of agricultural land use on water quality, with the intake of NO3- as well as SO42-, Cl- and Ca2+. Chalk groundwater geochemistry is compared with the nature and structure of the UZ. We highlight correlations (1) between thick clay-with-flints layers and the ions Mg2+ and K+, and (2) between UZ thickness and Na+. In conclusion, this paper identifies various ion sources (agriculture, clay-with-flints and Chalk) and demonstrates different processes in the UZ: dissolution, ionic exchange and solute storage.

  19. The flow mechanism in the Chalk based on radio-isotope analyses of groundwater in the London Basin

    USGS Publications Warehouse

    Downing, R.A.; Pearson, F.J.; Smith, D.B.

    1979-01-01

    14C analyses of groundwaters from the Chalk of the London Basin are re-interpreted and the age of the groundwater is revised. Radio-isotope analyses are used to examine the flow mechanism in the aquifer. The evidence supports the view that a network of micro-fissures and larger intergranular pores in the matrix provides a significant part of the water pumped from Chalk wells and the major fissures distribute the water to the wells. Most of the matrix is fine-grained and contains a very old water. This diffuses into the micro-fissures and larger pores and is carried to the wells by the major fissures. ?? 1979.

  20. AECL/US INERI - Development of Inert Matrix Fuels for Plutonium and Minor Actinide Management in Power Reactors -- Fuel Requirements and Down-Select Report

    SciTech Connect

    William Carmack; Randy D. Lee; Pavel Medvedev; Mitch Meyer; Michael Todosow; Holly B. Hamilton; Juan Nino; Simon Philpot; James Tulenko

    2005-06-01

    The U.S. Advanced Fuel Cycle Program and the Atomic Energy Canada Ltd (AECL) seek to develop and demonstrate the technologies needed to minimize the overall Pu and minor actinides present in the light water reactor (LWR) nuclear fuel cycles. It is proposed to reuse the Pu from LWR spent fuel both for the energy it contains and to decrease the hazard and proliferation impact resulting from storage of the Pu and minor actinides. The use of fuel compositions with a combination of U and Pu oxide (MOX) has been proposed as a way to recycle Pu and/or minor actinides in LWRs. It has also been proposed to replace the fertile U{sup 238} matrix of MOX with a fertile-free matrix (IMF) to reduce the production of Pu{sup 239} in the fuel system. It is important to demonstrate the performance of these fuels with the appropriate mixture of isotopes and determine what impact there might be from trace elements or contaminants. Previous work has already been done to look at weapons-grade (WG) Pu in the MOX configuration [1][2] and the reactor-grade (RG) Pu in a MOX configuration including small (4000 ppm additions of Neptunium). This program will add to the existing database by developing a wide variety of MOX fuel compositions along with new fuel compositions called inert-matrix fuel (IMF). The goal of this program is to determine the general fabrication and irradiation behavior of the proposed IMF fuel compositions. Successful performance of these compositions will lead to further selection and development of IMF for use in LWRs. This experiment will also test various inert matrix material compositions with and without quantities of the minor actinides Americium and Neptunium to determine feasibility of incorporation into the fuel matrices for destruction. There is interest in the U.S. and world-wide in the investigation of IMF (inert matrix fuels) for scenarios involving stabilization or burn down of plutonium in the fleet of existing commercial power reactors. IMF offer the

  1. Mechanical and chemical processes affecting the chalk during burial, insights from combined reflection seismics, well data and field work

    NASA Astrophysics Data System (ADS)

    Moreau, Julien; Boussaha, Myriam; Nielsen, Lars; Thibault, Nicolas; Stemmerik, Lars

    2014-05-01

    The chalk must undergo several phases of grain reorganisation and chemical reactions during its diagenetic evolution from a carbonaceous ooze to a sedimentary rock. Some of these transformations could be observed on structures from the kilometre- to the micrometre-scale with seismic reflection and cores analyses, respectively. However, few sites allow to combine all the different scale of observation for chalk diagenesis. Onshore and offshore high resolution seismics, two fully cored >350 m wells with wireline logging tools and very high quality exposures from a coastal cliff and a quarry form such an exceptional dataset in the Stevns peninsula area, eastern Danish Basin (Denmark). The studied chalk interval in the area is of Maastrichtian to Danian age. The chalk has been divided in 4 lithofacies, chalk-marl alternations, white chalk, white chalk with flint layers and bryozoan chalk. Advanced stratigraphic works have been performed with astronomical calibration based on stable isotope stratigraphy, wireline logs as well as several palaeontological proxies and detailed sedimentological analysis. Since a couple of decades, a specific kind of fractures has been described in the Chalk of Denmark, the so-called hairline fractures. They have recently been interpreted as compaction bands associated with the pore collapse of the chalk. We have observed these fractures on the field and on the cores in specific intervals. At depth, these fractures are in genetic relation with the formation of some stylolithes. The pressure-solution allows the formation of carbonate seams in the hairline fractures. At larger scale, on the field are observed faults which are sealed with flint precipitations. They slightly offset (<1 m) strata underlined by flint bands. On the onshore and offshore seismic reflection profiles, numerous strata-bound faults form noisy intervals as well as amplitude anomalies. Their normal offsets are less than 25 m. Their branching patterns, and their restriction

  2. Hydrological role of karst in the Chalk aquifer of Upper Normandy, France

    NASA Astrophysics Data System (ADS)

    El Janyani, Sanae; Dupont, Jean-Paul; Massei, Nicolas; Slimani, Smail; Dörfliger, Nathalie

    2014-05-01

    The role of karst on large-scale groundwater flow is defined for the Chalk aquifer of Upper Normandy (western Paris Basin), France. In the regional context, chalk plateaus occupy the greater part of watersheds and are the main sites of groundwater recharge. Previous studies focused on karstic output systems in the valleys and less on water-level variations in the recharge zones upstream. This study assesses the relevant hydrogeological processes using time-series data (boreholes and springs) recorded along a down-gradient hydrologeological cross-section in two selected watersheds. These hydrological data are interpreted in the framework of previous descriptions of the morphological organization of the study area's karst network. The results highlight the hydrological role of (1) the input karst (vertical conduits) which drains recharging water, (2) the output karst (sub-horizontal conduits widely developed in the vicinity of valleys in the surface watersheds) which drains the output flows, and (3) the connections between these two (input and output) networks, which control the upstream water levels and allow quick transfer to springs, particularly after strong rainfall events. A conceptual model of the hydrological functioning of this covered karst aquifer is established, which should serve for the structuring and parameterization of a numerical model.

  3. Hydrological responses of the chalk aquifer to the regional climatic signal

    NASA Astrophysics Data System (ADS)

    El Janyani, Sanae; Massei, Nicolas; Dupont, Jean-Paul; Fournier, Matthieu; Dörfliger, Nathalie

    2012-09-01

    SummaryPiezometric variability was investigated using monthly time series from 40 piezometers in different areas across the Upper Normandy region, over the 1968-2009 period. The piezometers were classified according to their hydrological behaviour. This paper aimed at characterising the dominant modes explaining piezometric variability and at investigating the causes of this variability. Significant components in the piezometric signals were identified: the annual cycle and an interannual mode (4-12 years) with different variances for each observation borehole group. The influence of the morphostructural organisation of the Upper Normandy chalk plateau on the modalities of the water level variability in the chalk aquifer was defined. The relative contributions and standard deviations of each component found in the signal time series of the groundwater level was estimated. The highest values were recorded in the Northern study area, and clay-with-flints and aquifer thicknesses influence the transfer on an annual scale, while the loess thickness influences the transfer on a multi-year scale.

  4. Nanoscale Pore Imaging and Pore Scale Fluid Flow Modeling in Chalk

    SciTech Connect

    Tomutsa, Liviu; Silin, Dmitriy

    2004-08-19

    For many rocks of high economic interest such as chalk, diatomite, tight gas sands or coal, nanometer scale resolution is needed to resolve the 3D-pore structure, which controls the flow and trapping of fluids in the rocks. Such resolutions cannot be achieved with existing tomographic technologies. A new 3D imaging method, based on serial sectioning and using the Focused Ion Beam (FIB) technology has been developed. FIB allows for the milling of layers as thin as 10 nanometers by using accelerated Ga+ ions to sputter atoms from the sample surface. After each milling step, as a new surface is exposed, a 2D image of this surface is generated. Next, the 2D images are stacked to reconstruct the 3D pore or grain structure. Resolutions as high as 10 nm are achievable using such a technique. A new robust method of pore-scale fluid flow modeling has been developed and applied to sandstone and chalk samples. The method uses direct morphological analysis of the pore space to characterize the petrophysical properties of diverse formations. Not only petrophysical properties (porosity, permeability, relative permeability and capillary pressures) can be computed but also flow processes, such as those encountered in various IOR approaches, can be simulated. Petrophysical properties computed with the new method using the new FIB data will be presented. Present study is a part of the development of an Electronic Core Laboratory at LBNL/UCB.

  5. Resolution dependence of petrophysical parameters derived from X-ray tomography of chalk

    SciTech Connect

    Müter, D.; Sørensen, H. O.; Jha, D.; Harti, R.; Dalby, K. N.; Stipp, S. L. S.; Suhonen, H.; Feidenhans'l, R.; Engstrøm, F.

    2014-07-28

    X-ray computed tomography data from chalk drill cuttings were taken over a series of voxel dimensions, ranging from 320 to 25 nm. From these data sets, standard petrophysical parameters (porosity, surface area, and permeability) were derived and we examined the effect of the voxel dimension (i.e., image resolution) on these properties. We found that for the higher voxel dimensions, they are severely over or underestimated, whereas for 50 and 25 nm voxel dimension, the resulting values (5%–30% porosity, 0.2–2 m{sup 2}/g specific surface area, and 0.06–0.34 mD permeability) are within the expected range for this type of rock. We compared our results to macroscopic measurements and in the case of surface area, also to measurements using the Brunauer-Emmett-Teller (BET) method and found that independent of the degree of compaction, the results from tomography amount to about 30% of the BET method. Finally, we concluded that at 25 nm voxel dimension, the essential features of the nanoscopic pore network in chalk are captured but better resolution is still needed to derive surface area.

  6. Chalk-calcite-microfluidic experiments: construction and flooding of microsystems with reactive fluids

    NASA Astrophysics Data System (ADS)

    Neuville, Amélie; Thuy Luu, Thi; Dysthe, Dag Kristian; Vinningland, Jan Ludvig; Hiorth, Aksel

    2015-04-01

    Direct in situ observation of the pore structure changes that occur when chalk is flooded with brines could resolve many of the open questions that remain about the interactions between mineralogical alterations and oil-liberating mechanisms. Experiments on core scale and field tests that have been carried out the last decade have clearly shown that water chemistry affects the final oil recovery. However, there is generally no consensus in the scientific community of why additional oil is released. In this work, our aim is to focus on in-situ observations of single phase flow and interactions at the pore scale. To do so, we create several types of custom-made microsystems with chalk and calcite crystals. We then do experiments with reacting fluids in these microsystems. During these experiments, we realize in-situ observations (geometrical characteristics, reaction rate) using microsopy techniques (white light vertical/phase shift interferometric microscopy, and classical microscopy), and show how they vary as function as the water chemistry. In simple systems made of calcite, we obtain reactive rates that are coherent with the litterature and with numerical simulations based on Lattice-Boltzmann methods.

  7. Mineral, chemical and textural relationships in rhythmic-bedded, hydrocarbon-productive chalk of the Niobrara Formation, Denver Basin, Colorado ( USA).

    USGS Publications Warehouse

    Pollastro, R.M.; Martinez, C.J.

    1985-01-01

    The types of hydrocarbons produced from these chalks are determined by the level of thermal maturity associated with present-day burial or paleoburial conditions. Detailed analyses of deeply-buried chalk from core of the Smoky Hill Chalk Member of the Niobrara Formation in the Champlin Petroleum 2 Boxelder Farms well combined with core data from other Niobrara wells have helped identify many depositional and diagenetic relationships. Porosity of the chalk is proportional to maximum burial depth and inversely proportional to the amount of non-carbonate material (acid- insoluble residue content) in the chalk. Total organic carbon content in the chalk is proportional to the amount of acid-insoluble residue and relative abundance of pyrite in the acid-insoluble fraction. Quartz is inversely proportional to the amount of insoluble material, and the amount of clay tends to increase as insolubles increase, suggesting that detritus in these chalks is greatly influenced by reworked, altered, volcanic products rather than siliceous clastics.-from Authors

  8. A multidisciplinary approach to reservoir subdivision of the Maastrichtian chalk in the Dan field, Danish North Sea

    SciTech Connect

    Kristensen, L.; Dons, T.; Schioler, P.

    1995-11-01

    Correlation of wireline log data from the North Sea chalk reservoirs is frequently hampered by rather subtle log patterns in the chalk section due to the apparent monotonous nature of the chalk sediments, which may lead to ambiguous correlations. This study deals with a correlation technique based on an integration of biostratigraphic data, seismic interpretation, and wireline log correlation; this technique aims at producing a consistent reservoir subdivision that honors both the well data and the seismic data. This multidisciplinary approach has been used to subdivide and correlate the Maastrichtian chalk in the Dan field. The biostratigraphic subdivision is based on a new detailed dinoflagellate study of core samples from eight wells. Integrating the biostratigraphic results with three-dimensional seismic data allows recognition of four stratigraphic units within the Maastrichtian, bounded by assumed chronostratigraphic horizons. This subdivision is further refined by adding a seismic horizon and four horizons from wireline log correlations, establishing a total of nine reservoir units. The approximate chronostratigraphic nature of these units provides an improved interpretation of the depositional and structural patterns in this area. The three upper reservoir units pinch out and disappear in a northeasterly direction across the field. We interpret this stratal pattern as reflecting a relative sea level fall or regional basinal subsidence during the latest Maastrichtian, possibly combined with local synsedimentary uplift due to salt tectonics. Isochore maps indicate that the underlying six non-wedging units are unaffected by salt tectonics.

  9. Dual FIB-SEM 3D imaging and lattice boltzmann modeling of porosimetry and multiphase flow in chalk.

    SciTech Connect

    Rinehart, Alex; Petrusak, Robin; Heath, Jason E.; Dewers, Thomas A.; Yoon, Hongkyu

    2010-12-01

    Mercury intrusion porosimetry (MIP) is an often-applied technique for determining pore throat distributions and seal analysis of fine-grained rocks. Due to closure effects, potential pore collapse, and complex pore network topologies, MIP data interpretation can be ambiguous, and often biased toward smaller pores in the distribution. We apply 3D imaging techniques and lattice-Boltzmann modeling in interpreting MIP data for samples of the Cretaceous Selma Group Chalk. In the Mississippi Interior Salt Basin, the Selma Chalk is the apparent seal for oil and gas fields in the underlying Eutaw Fm., and, where unfractured, the Selma Chalk is one of the regional-scale seals identified by the Southeast Regional Carbon Sequestration Partnership for CO2 injection sites. Dual focused ion - scanning electron beam and laser scanning confocal microscopy methods are used for 3D imaging of nanometer-to-micron scale microcrack and pore distributions in the Selma Chalk. A combination of image analysis software is used to obtain geometric pore body and throat distributions and other topological properties, which are compared to MIP results. 3D data sets of pore-microfracture networks are used in Lattice Boltzmann simulations of drainage (wetting fluid displaced by non-wetting fluid via the Shan-Chen algorithm), which in turn are used to model MIP procedures. Results are used in interpreting MIP results, understanding microfracture-matrix interaction during multiphase flow, and seal analysis for underground CO2 storage.

  10. Conference on the topic: {open_quotes}Exploration and production of petroleum and gas from chalk reservoirs worldwide{close_quotes}

    SciTech Connect

    Kuznetsov, V.G.

    1995-07-01

    More than 170 delegates from 14 countries in Europe, North America, Africa, and Asia took part in a conference on the topic: Exploration and Production of Petroleum and Gas from Chalk Reservoirs Worldwide. The conference was held in Copenhagen, Denmark in September,1994, and was a joint meeting of the American Association of Petroleum Geologists (AAPG), and the European Association of Petroleum Geoscientists and Engineers (EAPG). In addition to the opening remarks, 25 oral and nine poster reports were presented. The topics included chalk deposits as reservoir rocks, the occurrence of chalk deposits worldwide, the North Sea oil and gas fields, and other related topics.

  11. Evaluation of calabash chalk effect on femur bone morphometry and mineralization in young wistar rats: A pilot study

    PubMed Central

    Ekong, Moses B; Ekanem, Theresa B; Sunday, Abraham O; Aquaisua, Aquaisua N; Akpanabiatu, Monday I

    2012-01-01

    Background: Calabash chalk, a popularly consumed geophagic material in Nigeria has been reported to contain lead, arsenic, alpha lindane, endrin, and endosulfan 11 among other pollutants. Aim: The continuous exposure of young children to this chalk necessitated this study on the bone morphometry and mineralization in young Wistar rats. Materials and Methods: Fourteen young (weanling) Wistar rats of both sexes weighing 54-72 g were assigned into two groups of seven animals each. Group I served as control, while group II was the test group (TG). 40 mg/ml of C. chalk was administered as suspension to the test animals in group II. Animals in the control group were orally treated with 1ml of distilled water. Administration of the C. chalk in the animals lasted for 28 days, and the animals were sacrificed on day 29, using chloroform anaesthesia. The femur bones were dissected out, cleaned of flesh and sun-dried. The lengths and weights of the femur bones were measured using graphite furnace atomic mass spectrophotometer. Results: Results showed 1.6% decrease in body weight change in the TG, insignificant decreases in the weights and lengths of both the right and left femur bones, and significant decreased (P < 0.0126) organ-somatic index, and femur bones concentrations (mg/l) of zinc, phosphate, carbonate, calcium, sodium, and potassium (P < 0.05). Conclusion: In conclusion, this study showed that C. chalk may alter growth rate, and cause de-mineralization in the femur bone, hence, it may be detrimental to bone growth. PMID:23776822

  12. Tracking selenium behaviour in chalk aquifer (northern France): Sr and 34S-sulphates isotopes constraints.

    NASA Astrophysics Data System (ADS)

    Cary, Lise; Benabderraziq, Hind; Elkhattabi, Jamal; Parmentier, Marc; Gourcy, Laurence; Négrel, Philippe

    2014-05-01

    Groundwaters in parts of the Paris Basin (France) are facing increasing selenium (Se) contents that can exceed the drinking water limit of 10 μg/L according to the European Framework Directive in the field of water policy (2000/60/EC). To better understand the groundwater origins and the selenium dynamics, the water chemistry of the Chalk aquifer supplying drinkable water to Lille city was studied. This area is submitted to quantitative and qualitative pressure from industrial, urban and agriculture origins. An integrated study was settled to determine the water sources and dynamics of elements, with a focus on Se. After a large chemical characterisation of the groundwater chemistry in the four field wells, a monthly monitoring was held in four wells and in the Deûle channel. Chemical analysis of major and trace elements, stable isotopes (δ18O, δ2H), strontium isotopes, and δ34S and δ18O of sulphates were realised. The chemical composition of solids sampled at various depths at vicinity of the four wells was also analysed. The specific geochemical signature of groundwater as revealed by Sr isotopes, in addition to element concentrations ratios like Mg/Sr and Se/Sr, highlighted mixture of three main groundwaters bodies: (1) the upstream groundwaters in the recharge area with the most radiogenic 87Sr/86Sr isotopic signature; (2) the confined groundwaters with high Sr concentrations due to water-rock interactions and the lowest 87Sr/86Sr isotopic signature close to the one of the chalk in Paris and London basins; (3) the Se-rich formations of Tertiary and Quaternary. The contents of Se, mainly present as SeV I (and locally as SeIV ), displayed spatial and temporal disparities that can be explained by geological and hydrogeological conditions. Se-rich clayed sediments originating from the dismantling of Se-rich tertiary formations (i.e. Ypresian) overlay the chalk formation and can be found in saturated conditions depending of the water table level. Oxidation of

  13. Multi isotopic tools to understand selenium origins in groundwaters of the Chalk aquifer in Northern France

    NASA Astrophysics Data System (ADS)

    Cary, Lise; Gourcy, Laurence; Benabderraziq, Hind; Elkhattabi, Jamal; Laurent, Alexandra; Négrel, Philippe

    2013-04-01

    Four field wells exploiting the Chalk aquifer supply Lille city in water. The little catchment area is submitted to quantitative and qualitative pressure from industrial, urban and agriculture origins. Selenium (Se) concentrations are often higher than EU standards (0.12 µmol.L-1) for potable drinking water and can reach 0.4 μmol.L-1 leading to exploitation restrictions. An integrated study was settled to determine the water sources and dynamics of elements, with a focus on Se, with the goal of managing both water quality and quantity. After a large chemical characterisation of the system, a monthly sampling campaign was held in 2012 in four wells and in the close Deûle channel. In situ physical and chemical parameters, chemical analysis of major and trace elements with a special focus on redox-sensitive elements including SeIV, SeVI, FeII, stable water isotopes (δ18O, δ2H) and δ34S and δ18O of sulphates measures were undertaken. The chemical composition of solids sampled at various depths at vicinity of the four wells was analysed. Se concentrations in groundwaters and in the solid phase vary significantly. In the northern part of the Ansereuilles north of the Deûle channel, where the highest Se concentrations in solids was found in a 13 m alluvial clay deposit above the chalk, a first main type of waters can be defined with the variable and locally highest Se concentrations (0.19 to 0.4 µmol.L-1), relatively high and stable sulphate concentrations (2.5 µmol/L), no nitrates, dissolved Fe and Mn, negative δ34S (around -20 ‰) and δ18O typical of evaporated waters. A second main type of waters can be described at Houplin, south of the Deûle channel, where the geological profile show less than 1 mg/kg of Se, with intermediate Se concentrations (0.1 to 0.2 µmol/L), variable nitrate concentrations (0.4 to 1.2 mmol/L), not quantified dissolved Fe and Mn, sulphate concentrations close to 1.5 mmol/L, variable negative δ34S (-8 to -24 ‰) and δ18O in the

  14. Campanian ammonites from the Upper Cretaceous Gober Chalk of Lamar County, Texas

    USGS Publications Warehouse

    Cobban, W.A.; Kennedy, W.J.

    1992-01-01

    The Roxton Limestone Member at the top of the Gober Chalk in northeast Texas yields a rich fauna, dominated by Baculites haresi Reeside, 1927, and Inoceramus balticus Boehm, 1909, with sparse occurrences of pachydiscus cf. P. paulsoni (Young, 1963), Anapachydiscus sp.juv., Placenticeras placenta (DeKay, 1828), Hoplitoplacenticeras aff. H. plasticum (Paulcke, 1907), Menabites (Delawarella) delawarensis (Morton, 1830), M.(D.) danei (Young, 1963), M.(D.) aff. M.(D.) vanuxemi (Morton, 1830), Submortoniceras vandalinaense Young, 1963, Submortoniceras sp., Eubostrychoceras sp., and Scaphites hippocrepis (DeKay, 1828) III. The presence of S. hippocrepis III suggests a late early Campanian age assignment for the fauna. The assemblage includes species known from the Western Interior, Gulf Coast, Atlantic seaboard, and western Europe. -Authors

  15. Palaeoclimatic changes during the Upper Cretaceous of eastern Denmark: a study based on the Stevns-2 chalk core

    NASA Astrophysics Data System (ADS)

    Boussaha, M.; Stemmerik, L.; Thibault, N.

    2013-12-01

    The Stevns-2 core located in eastern Denmark penetrated close to 350 m of upper Campanian-Maastrichtian sediments of the upper Chalk Group (Stemmerik et al., 2006). The calcareous nannofossil biozonation spans the time interval from the UC16aBP from the upper Campanian to the NNT1 in the lowermost Danian. Carbon and Oxygen isotopes trends records climatic events occurring in the upper Cretaceous: (1) the Late Campanian warm climatic optimum, (2) the early Maastrichtian cooling event, (3) the mid-Maastrichtian warming event, and (4) the late Maastrichtian cooling event, also observed in the nearby Stevns-1 core (Thibault et al., 2011) . These climatic variations match closely those observed in the nearby Stevns-1 core and in the Atlantic, Pacific and Tethyan realms (Thibault & GARDIN, 2006; Thibault et al., 2011). Changes occurring in the number of observed Inoceramids prisms per meter of core section, in the abundance of calcareous nannofossils and in the visible trace fossils abundances seem to be linked to climatic changes as expressed in the δ18O of the bulk sediment. In addition to the sedimentological data show that the distribution of facies through time from: (1) cyclic marl alternating with mudstone-wackestone chalk and conglomerates, to (2) bioturbated white mudstone and wackestone chalk, then to (3) flint alternating with mudstone and wackestone chalk, ending with (5) bryozoans wackestone and packstone, and the sedimentation rate changes varying from 1.4 cm/kyr to 13.4 cm/kyr. Here we show how changes in the sedimentology of the chalk and abundances of different fossil group are influenced by global and regional mechanisms. Isotopic results mainly reflect global paleoclimatic changes, whereas the sedimentological record is mostly influenced by (1) local variations in paleoproductivity, (2) deep-water paleocurrents influencing the chalk deposition and the shape of the sea-floor, (3) and (4) the geodynamic activity and paleotopography of the Late

  16. Dual FIB-SEM 3D Imaging and Lattice Boltzmann Modeling of Porosimetry and Multiphase Flow in Chalk

    NASA Astrophysics Data System (ADS)

    Rinehart, A. J.; Yoon, H.; Dewers, T. A.; Heath, J. E.; Petrusak, R.

    2010-12-01

    Mercury intrusion porosimetry (MIP) is an often-applied technique for determining pore throat distributions and seal analysis of fine-grained rocks. Due to closure effects, potential pore collapse, and complex pore network topologies, MIP data interpretation can be ambiguous, and often biased toward smaller pores in the distribution. We apply 3D imaging techniques and lattice-Boltzmann modeling in interpreting MIP data for samples of the Cretaceous Selma Group Chalk. In the Mississippi Interior Salt Basin, the Selma Chalk is the apparent seal for oil and gas fields in the underlying Eutaw Fm., and, where unfractured, the Selma Chalk is one of the regional-scale seals identified by the Southeast Regional Carbon Sequestration Partnership for CO2 injection sites. Dual focused ion - scanning electron beam and laser scanning confocal microscopy methods are used for 3D imaging of nanometer-to-micron scale microcrack and pore distributions in the Selma Chalk. A combination of image analysis software is used to obtain geometric pore body and throat distributions and other topological properties, which are compared to MIP results. 3D data sets of pore-microfracture networks are used in Lattice Boltzmann simulations of drainage (wetting fluid displaced by non-wetting fluid via the Shan-Chen algorithm), which in turn are used to model MIP procedures. Results are used in interpreting MIP results, understanding microfracture-matrix interaction during multiphase flow, and seal analysis for underground CO2 storage. This work was supported by the US Department of Energy, Office of Basic Energy Sciences as part of an Energy Frontier Research Center. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

  17. Geologic models and evaluation of undiscovered conventional and continuous oil and gas resources: Upper Cretaceous Austin Chalk

    USGS Publications Warehouse

    Pearson, Krystal

    2012-01-01

    The Upper Cretaceous Austin Chalk forms a low-permeability, onshore Gulf of Mexico reservoir that produces oil and gas from major fractures oriented parallel to the underlying Lower Cretaceous shelf edge. Horizontal drilling links these fracture systems to create an interconnected network that drains the reservoir. Field and well locations along the production trend are controlled by fracture networks. Highly fractured chalk is present along both regional and local fault zones. Fractures are also genetically linked to movement of the underlying Jurassic Louann Salt with tensile fractures forming downdip of salt-related structures creating the most effective reservoirs. Undiscovered accumulations should also be associated with structure-controlled fracture systems because much of the Austin that overlies the Lower Cretaceous shelf edge remains unexplored. The Upper Cretaceous Eagle Ford Shale is the primary source rock for Austin Chalk hydrocarbons. This transgressive marine shale varies in thickness and lithology across the study area and contains both oil- and gas-prone kerogen. The Eagle Ford began generating oil and gas in the early Miocene, and vertical migration through fractures was sufficient to charge the Austin reservoirs.

  18. Mass-transport deposits and reservoir quality of Upper Cretaceous Chalk within the German Central Graben, North Sea

    NASA Astrophysics Data System (ADS)

    Arfai, Jashar; Lutz, Rüdiger; Franke, Dieter; Gaedicke, Christoph; Kley, Jonas

    2016-04-01

    The architecture of intra-chalk deposits in the `Entenschnabel' area of the German North Sea is studied based on 3D seismic data. Adapted from seismic reflection characteristics, four types of mass-transport deposits (MTDs) are distinguished, i.e. slumps, slides, channels and frontal splay deposits. The development of these systems can be linked to inversion tectonics and halotectonic movements of Zechstein salt. Tectonic uplift is interpreted to have caused repeated tilting of the sea floor. This triggered large-scale slump deposition during Turonian-Santonian times. Slump deposits are characterised by chaotic reflection patterns interpreted to result from significant stratal distortion. The south-eastern study area is characterised by a large-scale frontal splay complex. This comprises a network of shallow channel systems arranged in a distributive pattern. Several slide complexes are observed near the Top Chalk in Maastrichtian and Danian sediments. These slides are commonly associated with large incisions into the sediments below. Best reservoir properties with high producible porosities are found in the reworked chalk strata, e.g. Danish North Sea, therefore MTDs detected in the study area are regarded as potential hydrocarbon reservoirs and considered as exploration targets.

  19. Integrating geophysical and hydrochemical borehole-log measurements to characterize the Chalk aquifer, Berkshire, United Kingdom

    NASA Astrophysics Data System (ADS)

    Schürch, Marc; Buckley, David

    2002-09-01

    Geophysical and hydrochemical borehole-logging techniques were integrated to characterize hydraulic and hydrogeochemical properties of the Chalk aquifer at boreholes in Berkshire, UK. The down-hole measurements were made to locate fissures in the chalk, their spatial extent between boreholes, and to determine the groundwater chemical quality of the water-bearing layers. The geophysical borehole logging methods used were caliper, focused resistivity, induction resistivity, gamma ray, fluid temperature, fluid electrical conductivity, impeller and heat-pulse flowmeter, together with borehole wall optical-imaging. A multiparameter data transmitter was used to measure groundwater temperature, electrical conductivity, dissolved oxygen, pH, and redox potential of the borehole fluid down-hole. High permeability developed at the Chalk Rock by groundwater circulation provides the major flow horizon at the Banterwick Barn study site and represents a conduit system that serves as an effective local hydraulic connection between the boreholes. The Chalk Rock includes several lithified solution-ridden layers, hardgrounds, which imply a gap in sedimentation possibly representing an unconformity. Lower groundwater temperature, high dissolved-oxygen content, and flowmeter evidence of preferential groundwater flow in the Chalk Rock indicated rapid groundwater circulation along this horizon. By repeating the logging at different times of the year under changing hydraulic conditions, other water-inflow horizons within the Chalk aquifer were recognized. Résumé. Des techniques géophysiques et hydrochimiques de diagraphies en forage ont été mises en oeuvre pour caractériser les propriétés hydrauliques et hydrogéochimiques de l'aquifère de la craie dans des forages du Berkshire (Grande-Bretagne). Les mesures en descente ont été faites pour localiser les fissures dans la craie et leur développement spatial entre forages, et pour déterminer la qualité de l'eau souterraine des

  20. Characterization of Acid Mine Drainage Sources Using Stable and Radiogenic Isotopes, Chalk Creek, Colorado

    NASA Astrophysics Data System (ADS)

    Cordalis, D.; Michel, R.; Williams, M.; Wireman, M.

    2003-12-01

    Acid mine drainage (AMD) affects many streams throughout the western United States. Understanding flow dynamics and sources within a fractured rock setting is necessary in outlining a potential remediation strategy for AMD. Radiogenic and stable isotopes of water were used in the Mary Murphy Mine, Chalk Creek, Colorado, in order to characterize flowpaths and sourcewaters. By delineating the sources of the mine water, groundwater, and event water, we may be able to target remediation techniques for individual contamination sources. Moreover, results from this research provide insights into groundwater flow systems in mountain environments of the Colorado Rockies. Tritium, a cosmogenic isotope of hydrogen, has a half-life 12.43y and is useful for studying hydrologic processes at the decadal time scale and can be used as an effective tracer when traditional chemical tracers are non-conservative. Hydrometric information showed that discharge from the mine adit exhibited a hydrograph characteristic of snowmelt runoff. However, mixing models using stable water isotopes (D and 18O) found less than 7% of the mine's peak discharge was from snowmelt, suggesting a regional groundwater dominated system. Mine interior samples fell into two characteristic groupings: either from the extreme north side of the drift which contained most of the zinc contamination, and all other locations. The waters from the north drift, MVN-3 and MVN-4, had lower 18O values, -17.62 per mil and -17.17 per mil, respectively, than did any of the other locations, suggesting a seasonal snowmelt input. However, the tritium values associated with MVN-3 and MVN-4 suggest at least some mixing, with values of 13.4 TU and 12.5 TU, respectively. Surface water samples from Chalk Creek show average tritium values of 11.1 TU, and 18O values of -14.87 per mil. Groundwater samples were captured using monitoring wells, and plotted according to the depth of screening. Alluvial wells carried a seasonal signal similar

  1. Speciation and weathering of selenium in upper cretaceous chalk and shale from South Dakota and Wyoming, USA

    NASA Astrophysics Data System (ADS)

    Kulp, Thomas R.; Pratt, Lisa M.

    2004-09-01

    In geologic materials, petroleum, and the environment, selenium occurs in various oxidation states (VI, IV, 0, -II), mineralized forms, and organo-Se complexes. Each of these forms is characterized by specific chemical and biochemical properties that control the element's solubility, toxicity, and environmental behavior. The organic rich chalks and shales of the Upper Cretaceous Niobrara Formation and the Pierre Shale in South Dakota and Wyoming are bentoniferous stratigraphic intervals characterized by anomalously high concentrations of naturally occurring Se. Numerous environmental problems have been associated with Se derived from these geological units, including the development of seleniferous soils and vegetation that are toxic to livestock and the contamination of drinking water supplies by Se mobilized in groundwater. This study describes a sequential extraction protocol followed by speciation treatments and quantitative analysis by Hydride Generation-Atomic Absorption Spectroscopy. This protocol was utilized to investigate the geochemical forms and the oxidation states in which Se occurs in these geologic units. Organic Se and di-selenide minerals are the predominant forms of Se present in the chalks, shales, and bentonites, but distinctive variations in these forms were observed between different sample types. Chalks contain significantly greater proportions of Se in the form of di-selenide minerals (including Se associated with pyrite) than the shales where base-soluble, humic, organo-Se complexes are more prevalent. A comparison between unweathered samples collected from lithologic drill cores and weathered samples collected from outcrop suggest that the humic, organic-Se compounds in shale are formed during oxidative weathering and that Se oxidized by weathering is more likely to be retained by shale than by chalk. Selenium enrichment in bentonites is inferred to result from secondary processes including the adsorption of Se mobilized by groundwater

  2. Fault and fracture patterns in low porosity chalk and their potential influence on sub-surface fluid flow-A case study from Flamborough Head, UK

    NASA Astrophysics Data System (ADS)

    Sagi, D. A.; De Paola, N.; McCaffrey, K. J. W.; Holdsworth, R. E.

    2016-10-01

    To better understand fault zone architecture and fluid flow in mesoscale fault zones, we studied normal faults in chalks with displacements up to 20 m, at two representative localities in Flamborough Head (UK). At the first locality, chalk contains cm-thick, interlayered marl horizons, whereas at the second locality marl horizons were largely absent. Cm-scale displacement faults at both localities display ramp-flat geometries. Mesoscale fault patterns in the marl-free chalk, including a larger displacement fault (20 m) containing multiple fault strands, show widespread evidence of hydraulically-brecciated rocks, whereas clays smears along fault planes, and injected into open fractures, and a simpler fault zone architecture is observed where marl horizons are present. Hydraulic brecciation and veins observed in the marl-free chalk units suggest that mesoscale fault patterns acted as localized fault conduit allowing for widespread fluid flow. On the other hand, mesoscale fault patterns developed in highly fractured chalk, which contains interlayered marl horizons can act as localized barriers to fluid flow, due to the sealing effect of clays smears along fault planes and introduced into open fractures in the damage zone. To support our field observations, quantitative analyses carried out on the large faults suggest a simple fault zone in the chalk with marl units with fracture density/connectivity decreasing towards the protolith. Where marls are absent, density is high throughout the fault zone, while connectivity is high only in domains nearest the fault core. We suggest that fluid flow in fractured chalk is especially influenced by the presence of marls. When present, it can smear onto fault planes, forming localised barriers. Fluid flow along relatively large displacement faults is additionally controlled by the complexity of the fault zone, especially the size/geometry of weakly and intensely connected damage zone domains.

  3. Contribution of piezometric measurement to knowledge and management of low water levels: examples on the chalk aquifer in the Champagne Ardennes region

    NASA Astrophysics Data System (ADS)

    Stollsteiner, P.; Bessiere, H.; Nicolas, J.; Allier, D.; Berthet, O.

    2015-04-01

    This article is based on a BRGM study on piezometric indicators, threshold values of discharge and groundwater levels for the assessment of potentially-exploitable water resources of chalky watersheds. A method for estimating low water levels based on groundwater levels is presented from three examples representing chalk aquifers with different cycles: annual, combined and interannual. The first is located in Picardy and the two others in the Champagne-Ardennes region. Piezometers with annual cycles, used in these examples, are supposed to be representative of the aquifer hydro-dynamics. Except for multi-annual systems, the analysis between discharge measurements at a hydrometric station and groundwater levels measured at a piezometer representative of the main aquifer, leads to relatively precise and satisfactory relationships within a chalky context. These relationships may be useful for monitoring, validation, extension or reconstruction of the low water flow data. On the one hand, they allow definition of the piezometric levels corresponding to the different alert thresholds of river discharges. On the other hand, they clarify the proportions of low surface water flow from runoff or drainage of the aquifer. Finally, these correlations give an assessment of the minimum flow for the coming weeks. However, these correlations cannot be used to optimize the value of the exploitable water resource because it seems to be difficult to integrate the value of the effective rainfall that could occur during the draining period. Moreover, in the case of multi-annual systems, the solution is to attempt a comprehensive system modelling and, if it is satisfactory, using the simulated values to get rid of parasites or running the model for forecasting purposes.

  4. Temporal variability of local abundance, sex ratio and activity in the Sardinian chalk hill blue butterfly

    USGS Publications Warehouse

    Casula, P.; Nichols, J.D.

    2003-01-01

    When capturing and marking of individuals is possible, the application of newly developed capture-recapture models can remove several sources of bias in the estimation of population parameters such as local abundance and sex ratio. For example, observation of distorted sex ratios in counts or captures can reflect either different abundances of the sexes or different sex-specific capture probabilities, and capture-recapture models can help distinguish between these two possibilities. Robust design models and a model selection procedure based on information-theoretic methods were applied to study the local population structure of the endemic Sardinian chalk hill blue butterfly, Polyommatus coridon gennargenti. Seasonal variations of abundance, plus daily and weather-related variations of active populations of males and females were investigated. Evidence was found of protandry and male pioneering of the breeding space. Temporary emigration probability, which describes the proportion of the population not exposed to capture (e.g. absent from the study area) during the sampling process, was estimated, differed between sexes, and was related to temperature, a factor known to influence animal activity. The correlation between temporary emigration and average daily temperature suggested interpreting temporary emigration as inactivity of animals. Robust design models were used successfully to provide a detailed description of the population structure and activity in this butterfly and are recommended for studies of local abundance and animal activity in the field.

  5. Incrusting and boring bryozoans from the Dessau Chalk Formation (Cretaceous), Little Walnut Creek, Austin, Texas

    SciTech Connect

    Morris, P.A. )

    1990-09-01

    Four sections were measured along a 1/4 mi length of Little Walnut Creek. The first section was 165 ft north of the US. 290 bridge while the fourth was 1/4 mi upstream. Structurally, the stream follows the fault in this section. Small faults can be found perpendicular to the primary fault and apparently account not only for minor variation in local dip (8{degrees}SE, parallel to 5{degrees}NW) but also for the placement of at least one tributary. Megainvertebrate exoskeletons were found to have been inhabited by incrusting bryozoans, boring bryozoans, and sponges. These fossils were found on both interior and exterior surfaces of Exogyra laeviuscula E tigrina, and interior surfaces of Inoceramus. A low-energy environment allowed exposure of megainvertebrate exoskeletons after death but also prevented fracturing. Low siltation rates also extended exoskeleton availability after organismic death. The nonboring bryozoans are cheilostomes and at least one species, Pyripora, has been described from the Kansas Cretaceous as well as European Cretaceous sites. The boring bryozoans are primarily represented by Terebripora sp. In conclusion, this section of Dessau Chalk Formation, Upper Austin Group, was mostly a low-energy environment, shallow, limy mud platform. This substrate was probably not stable enough for bryozoan colonization as unattached colonies have not been found in sediments. Therefore, bryozoan substrates were limited to living and dead Exogyra sp. and dead Inoceramus sp. exoskeletons.

  6. Long-term reactive transport modelling of Berea and chalk core flood experiment

    NASA Astrophysics Data System (ADS)

    Souza, A. V.; Godoy, J.; Tonietto, G.

    2013-12-01

    Carbon sequestration in geological structures establishes a long-term chemical system between the dissolved gas, fluids and rocks from the injection site. Thus, the time scale used to assess the progress of chemical reactions is normally between tens and hundreds of years. Geochemical modeling is used in a variety of fields, including environmental protection and remediation, the petroleum industry, and economic geology and it is one of the best alternatives to evaluate the reactions with geochemical data possible injection sites. In this work we used data presented in a recent article (SPE165500) in different scenarios injection with three scales 50, 100, 250 and 1000 years. The experimental data used were from core flood experiment Berea and chalk in a condition similar to those found in the reservoirs of the North Sea. (340 bar and 130 C). The approach used to the lack of appropriate kinetic parameter in reservoir conditions, was the use of experimental data collected in two different conditions (340 bar and 130 C) and (2 Bar at room temperature) after the rocky core. The numerical simulations carried out using the same conditions with two different geochemical softwares PHREEQC and TOUGHREACTS. The results provide a detailed understanding of the system resulting rock-fluid-CO2 in the medium and long term. However, the accuracy of the models is strongly dependent on the mineral primary and secondary cores found in rocks.

  7. Penetration of herbicides to groundwater in an unconfined chalk aquifer following normal soil applications.

    PubMed

    Johnson, A C; Besien, T J; Bhardwaj, C L; Dixon, A; Gooddy, D C; Haria, A H; White, C

    2001-12-01

    The persistence and penetration of the herbicides isoproturon and chlorotoluron in an unconfined chalk aquifer has been monitored over a 4-year period through soil sampling, shallow coring and groundwater monitoring. Chlorotoluron was applied on plots as a marker compound, having never been used previously on that, or surrounding fields. The fieldsite had a 5 degree slope with soil depths of 0.5 to 1.5 m and a water table between 20 and 5 m from the soil surface. Where the water table was deepest (9-20 m below surface (mbs)) little or no positive herbicide detections were made. However, where the water table was at only 4-5 mbs, a regular pesticide signal of around 0.1 microg/l for isoproturon and chlorotoluron could be distinguished. Over the winter recharge period automatic borehole samplers revealed a series of short-lived peaks of isoproturon and chlorotoluron reaching up to 0.8 microg/l. This is consistent with a preferential flow mechanism operating at this particular part of the field. Such peaks were occurring over 2 years after the last application of these compounds. Shallow coring failed to uncover any significant pesticide pulse moving through the deep unsaturated zone matrix at the fieldsite.

  8. Valuing river characteristics using combined site choice and participation travel cost models.

    PubMed

    Johnstone, C; Markandya, A

    2006-08-01

    This paper presents new welfare measures for marginal changes in river quality in selected English rivers. The river quality indicators used include chemical, biological and habitat-level attributes. Economic values for recreational use of three types of river-upland, lowland and chalk-are presented. A survey of anglers was carried out and using these data, two travel cost models were estimated, one to predict the numbers of trips and the other to predict angling site choice. These models were then linked to estimate the welfare associated with marginal changes in river quality using the participation levels as estimated in the trip prediction model. The model results showed that higher flow rates, biological quality and nutrient pollution levels affect site choice and influence the likelihood of a fishing trip. Consumer surplus values per trip for a 10% change in river attributes range from pound 0.04 to pound 3.93 ( pound 2001) depending on the attribute.

  9. The effect of aging, temperature and brine composition on the mechanical strength of chalk

    NASA Astrophysics Data System (ADS)

    Korsnes, Reidar Inge; Nermoen, Anders; Stødle, Trond; Vika Storm, Eirik; Vadla Madland, Merete

    2014-05-01

    Chalk strength has been of great focus for several research communities since the 1980s when the Ekofisk subsidence problem was discovered. Sea water injection was initiated in 1987 to improve the oil production and to re-pressurize the reservoirs to halt the subsidence. The oil production was improved significantly, but the reservoir compaction in the water saturated regions continued, in contrast to the regions with no water breakthrough. This observation indicates a water weakening effect of the chalk. Extensive studies have been performed during the last decades to enlighten how the brine chemistry alters the rock mechanical properties. These studies have shown that the elastic bulk modulus, yield strength, creep and the deformation rate at constant stress conditions depend on the pore fluid composition. In general, the injected brine is in non-equilibrium with the rock surface inducing alteration of the rock mineralogy. In this study we examined two aspects of the mechanical strength, namely the bulk modulus and the onset of yield during hydrostatic stress loading with 0.7 MPa pore pressure. The test program consisted of aged and un-aged cores, ambient and 130°C test temperature, and four brine compositions: MgCl2, NaCl, Na2SO4, and synthetic sea water (SSW) at ion strengths of 0.657 M. The aging was performed by submerging saturated cores in a closed container with the respective test brine for three weeks at 130°C. Un-aged cores were saturated the same day as they were tested. For each brine composition we present four test setups; (a) aged and tested at 130°C, (b) aged and tested at ambient temperature, (c) un-aged and tested at 130°C, and (d) un-aged and tested at ambient conditions. The main results from our study are: 1. By using NaCl and MgCl2 as saturating brines, neither the test temperature nor the aging procedure affected the yield stress and bulk modulus significantly. 2. Using Na2SO4, the yield point and bulk moduli were reduced if the core

  10. Compaction of North-sea chalk by pore-failure and pressure solution in a producing reservoir

    NASA Astrophysics Data System (ADS)

    Keszthelyi, Daniel; Dysthe, Dag; Jamtveit, Bjorn

    2016-02-01

    The Ekofisk field, Norwegian North sea,is an example of compacting chalk reservoir with considerable subsequent seafloor subsidence due to petroleum production. Previously, a number of models were created to predict the compaction using different phenomenological approaches. Here we present a different approach, we use a new creep model based on microscopic mechanisms with no fitting parameters to predict strain rate at core scale and at reservoir scale. The model is able to reproduce creep experiments and the magnitude of the observed subsidence making it the first microstructural model which can explain the Ekofisk compaction.

  11. The direct determination of the masses of unstable atoms with the chalk river on-line isotope separator

    NASA Astrophysics Data System (ADS)

    Sharma, K. S.; Schmeing, H.; Evans, H. C.; Hagberg, E.; Hardy, J. C.; Koslowsky, V. T.

    1989-02-01

    A new technique has been developed to measure the spacing of atomic mass doublets of radioactive isotopes directly with an on-line isotope separator. It relies not on ion detection but on observation of the specific radioactive signature of the isotopes under study. Consequently, line shapes and centroids can be determined, free of interference and with great accuracy, even if the corresponding beams strongly overlap or if they are contaminated by unwanted isobars or isomers. In particular, it is of no consequence if one or both members of the doublet are masked by stable background peaks. Doublets are peak matched as in a conventional mass spectrometer. The technique has been evaluated with beams of radioactive nuclides whose masses are known independently. Based on careful calibrations, two new mass values have been obtained: 72Br, 71 936 340 ± 430 μu and 63Ga, 62 939 570 ± 150 μu.

  12. Draft Genome Sequence of a Thermophilic Cyanobacterium from the Family Oscillatoriales (Strain MTP1) from the Chalk River, Colorado.

    PubMed

    Hallenbeck, Patrick C; Grogger, Melanie; Mraz, Megan; Veverka, Donald

    2016-02-18

    The draft genome (57.7% GC, 7,647,882 bp) of the novel thermophilic cyanobacterium MTP1 was determined by metagenomics of an enrichment culture. The genome shows that it is in the family Oscillatoriales and encodes multiple heavy metal resistances as well as the capacity to make exopolysaccharides.

  13. The behaviour and fate of Nitrate and Phosphate present in treated wastewater when discharged to the Chalk aquifer of SE England

    NASA Astrophysics Data System (ADS)

    Phillips, Richard; Smith, Martin; Pope, David

    2013-04-01

    The Chalk aquifer of South East England is a major groundwater resource and regionally supplies up to 70% of all water abstracted for potable purposes. The two main pressures on groundwater resources are considered to be climate change and population growth. As the demand for water increases, so does the volume of wastewater that has to be treated to acceptable levels before being discharged back into the environment. Aquifer storage and recovery (ASR) is form of groundwater resource management whereby water is pumped or injected into the ground and allowed to percolate through to the saturated zone before being abstracted at a later date. By injecting water into the ground during periods of high precipitation (i.e. winter months) an increased volume of water is made available for later abstraction (i.e. during summer months) helping water resource planners better manage the supply demand balance. In the case of using treated wastewater as a source for artificial recharge, there is little published research on the behaviour and fate of the main contaminants of concern that are found in treated wastewater when they are discharged to the principal aquifer (the Chalk) of SE England. Nitrate and Phosphate are listed (amongst others) as the main contaminants of concern that are present in treated wastewater and discharged to the Chalk aquifer when this practice occurs. The CLIMAWAT project is an EU-Regional Development Fund Interreg IV funded research programme to study the impacts of climate change on groundwater resources and groundwater quality from the Chalk aquifer of SE England. The use of treated wastewater for artificial recharge has been extensively studied in both the field and laboratory to better assess how sustainable this practice is in terms of risk of pollution to the groundwater body. The results of the laboratory programme include breakthrough curves for Nitrate and Phosphate in the Chalk matrix under unsaturated and saturated conditions. Whilst

  14. Infrared spectroscopy and density functional theory investigation of calcite, chalk, and coccoliths--do we observe the mineral surface?

    PubMed

    Andersson, M P; Hem, C P; Schultz, L N; Nielsen, J W; Pedersen, C S; Sand, K K; Okhrimenko, D V; Johnsson, A; Stipp, S L S

    2014-11-13

    We have measured infrared spectra from several types of calcite: chalk, freshly cultured coccoliths produced by three species of algae, natural calcite (Iceland Spar), and two types of synthetic calcite. The most intense infrared band, the asymmetric carbonate stretch vibration, is clearly asymmetric for the coccoliths and the synthetic calcite prepared using the carbonation method. It can be very well fitted by two peaks: a narrow Lorenzian at lower frequency and a broader Gaussian at higher frequency. These two samples both have a high specific surface area. Density functional theory for bulk calcite and several calcite surface systems allows for assignment of the infrared bands. The two peaks that make up the asymmetric carbonate stretch band come from the bulk (narrow Lorenzian) and from a combination of two effects (broad Gaussian): the surface or near surface of calcite and line broadening from macroscopic dielectric effects. We detect water adsorbed on the high surface area synthetic calcite, which permits observation of the chemistry of thin liquid films on calcite using transmission infrared spectroscopy. The combination of infrared spectroscopy and density functional theory also allowed us to quantify the amount of polysaccharides associated with the coccoliths. The amount of polysaccharides left in chalk, demonstrated to be present in other work, is below the IR detection limit, which is 0.5% by mass.

  15. Albanian violets of the section Melanium, their morphological variability, genetic similarity and their adaptations to serpentine or chalk soils.

    PubMed

    Słomka, Aneta; Godzik, Barbara; Szarek-Łukaszewska, Grażyna; Shuka, Lulëzim; Hoef-Emden, Kerstin; Bothe, Hermann

    2015-02-01

    Violets of the section Melanium from Albanian serpentine and chalk soils were examined for their taxonomic affiliations, their ability to accumulate heavy metals and their colonization by arbuscular mycorrhizal fungi (AMF). The sequence analysis of the ITS1-5.8S rDNA-ITS2 region showed that all the sampled six Albanian violets grouped between Viola lutea and Viola arvensis, but not with Viola tricolor. The fine resolution of the ITS sequences was not sufficient for a further delimitation of the Albanian violets within the V. lutea-V. arvensis clade. Therefore, the Albanian violets were classified by a set of morphological characters. Viola albanica, Viola dukadjinica and Viola raunsiensis from serpentine soils as well as Viola aetolica from a chalk meadow were unambiguously identified, whereas the samples of Viola macedonica showed high morphological variability. All the violets, in both roots and shoots contained less than or similar levels of heavy metals as their harboring soils, indicating that they were heavy metal excluders. All the violets were strongly colonized by AMF with the remarkable exception of V. albanica. This violet lived as a scree creeper in shallow serpentine soil where the concentration of heavy metals was high but those of P, K and N were scarce.

  16. Initiation conditions for debris flows generated by runoff at Chalk Cliffs, central Colorado

    NASA Astrophysics Data System (ADS)

    Coe, Jeffrey A.; Kinner, David A.; Godt, Jonathan W.

    2008-04-01

    We have monitored initiation conditions for six debris flows between May 2004 and July 2006 in a 0.3 km 2 drainage basin at Chalk Cliffs; a band of hydrothermally-altered quartz monzonite in central Colorado. Debris flows were initiated by water runoff from colluvium and bedrock that entrained sediment from rills and channels with slopes ranging from about 14° to 45°. The availability of channel material is essentially unlimited because of thick channel fill and refilling following debris flows by rock fall and dry ravel processes. Rainfall exceeding I = 6.61( D) - 0.77 , where I is rainfall intensity (mm/h), and D is duration (h), was required for the initiation of debris flows in the drainage basin. The approximate minimum runoff discharge from the surface of bedrock required to initiate debris flows in the channels was 0.15 m 3/s. Colluvium in the basin was unsaturated immediately prior to (antecedent) and during debris flows. Antecedent, volumetric moisture levels in colluvium at depths of 1 cm and 29 cm ranged from 4-9%, and 4-7%, respectively. During debris flows, peak moisture levels in colluvium at depths of 1 cm and 29 cm ranged from 10-20%, and 4-12%, respectively. Channel sediment at a depth of 45 cm was unsaturated before and during debris flows; antecedent moisture ranged from 20-22%, and peak moisture ranged from 24-38%. Although we have no measurements from shallow rill or channel sediment, we infer that it was unsaturated before debris flows, and saturated by surface-water runoff during debris flows. Our results allow us to make the following general statements with regard to debris flows generated by runoff in semi-arid to arid mountainous regions: 1) high antecedent moisture levels in hillslope and channel sediment are not required for the initiation of debris flows by runoff, 2) locations of entrainment of sediment by successive runoff events can vary within a basin as a function of variations in the thickness of existing channel fill and the

  17. Comparative estimates of transpiration of ash and beech forest at a chalk site in southern Britain

    NASA Astrophysics Data System (ADS)

    Roberts, John; Rosier, Paul T. W.

    1994-11-01

    (1) During the dry summer of 1989 stomatal conductance ( gs), boundary-layer conductance ( ga), leaf water and osmotic potentials ( ψ1, ψπ) and leaf area index ( L∗) measurements were made in mature ash and beech stands growing on shallow soil over chalk near Winchester, Hampshire, UK. In addition measurements of gs and L∗ were made in the understorey layer in the ash stand, comprised mainly of dog's mercury, hazel and bramble. Automatic weather stations located (i) above the beech stand and (ii) at the understorey level (within the ash stand) provided hourly averages of weather variables. Changes in soil moisture deficit in both stands were determined from regular measurements made with a neutron probe. (2) Maximum values of gs (up to 0.3 mol m -2 s -1) were found at the top of the ash and beech canopies at the start of the day, while at the canopy base gs was about half of these values. At all canopy levels the value of gs was more closely associated with specific humidity deficit (at the time of measurement) than with any other weather variable, and there was no relationship between gs and soil mositure deficit or leaf water status, described by ψ1 and ψπ on the day of measurement. (3) Values of gs of the understorey plants were only half those of the tree species and changed less during the day. However, seasonal changes in gs of dog's mercury did seem to be associated with increased soil moisture deficit. (4) Estimates of L∗ in the ash and beech stands were made from leaf litter collections and partitioned into canopy layers using ratios determined by destructive sampling. L∗ of the beech stand was 5.3 and for the ash stand 2.7. L∗ of the understorey varied seasonally and rose to a peak of 3 in June falling gradually for the remainder of the summer period. (5) Hourly values of gs and ga in each stand for each canopy layer were scaled up to the canopy by using L∗ of the individual canopy layers (including the understorey level in the ash stand

  18. Assessment of undiscovered oil and gas resources of the Upper Cretaceous Austin Chalk and Tokio and Eutaw Formations, Gulf Coast, 2010

    USGS Publications Warehouse

    Pearson, Krystal; Dubiel, R.F.; Pearson, O.N.; Pitman, J.K.

    2011-01-01

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated means of 957 million barrels of undiscovered oil, 3.6 trillion cubic feet of undiscovered natural gas, and 363 million barrels of undiscovered natural gas liquids in the Austin Chalk and Tokio and Eutaw Formations in onshore lands and State waters of the Gulf Coast.

  19. Chalk Is Cheap: Nurturing Teachers in a Famine Culture Professional Starvation Is Gnawing Away At Teacher Motivation. Here Are Some Ways For Principals To Provide Needed Nutrition.

    ERIC Educational Resources Information Center

    Schmidt, Laurel

    2005-01-01

    Scarcity has been such a constant in education for so long that self-sufficient teachers routinely purchase classroom supplies at their own expense. Sometimes desperate measures are needed to obtain even the most basic equipment. I heard of a teacher whose chalkboard was so slick from years of use that it had become chalk-proof. Her first graders…

  20. Modelling of nitrate leaching from arable land into unsaturated soil and chalk 2. Model confirmation and application to agricultural and sewage sludge management

    NASA Astrophysics Data System (ADS)

    Andrews, R. J.; Lloyd, J. W.; Lerner, D. N.

    1997-12-01

    A layered deterministic N-leaching model, IMPACT, has been calibrated using data from two study sites on the unconfined Chalk aquilfer of East Anglia, UK. The model predicts nitrogen species movement resulting from the application of sewage sludges and fertilizers to arable land for different vegetation-soil-hydrogeological conditions. One site received sludge in the form of digested sewage cake (DSC) for the first time during the study period, whilst the other site had over 15 years history of liquid undigested sludge (LUS) applications at 3 year intervals. Site data included: 3-monthly concentration profiles at 0.3 m intervals to depths of up to 6 m for N-species and chloride; unsaturated potential measurements; water level and saturated groundwater solute concentrations, fertilizer and sludge input; daily recharge, and soil/chalk type and moisture content. The observed average movement rate for nitrate peaks in the Lower Chalk, measured at one site, was 0.2 m year -2. Leachate peaks were not observed annually but approximately every third year, being associated with large sludge applications and ploughing of grass crops. Significant correlation between observed and modelled nitrate profiles in soil and chalk were obtained which demonstrated applications. The relationship between crop demand, application times of fertilizers and sludge, nitrate availability and recharge was shown strongly to control the shape of nitrate profiles in the soil and chalk and the quantity of nitrate leached tochalk. The change in hydrogeological conditions at the soil-chalk contact and associated potential for denitrification was also shown to exert a significant control on the shape of the nitrate profile. Following calibration, different arable crop and sludge application regimes were examined for a 6 year period and ranked according to their nitrate leaching risk. Of the modelled cereal farming scenarios, the crop/sludge regime giving the least nitrate leaching was a late autumn

  1. Characteristics of pore structures in Selma Chalk using dual FIB-SEM 3D imaging and Lattice Boltzmann Modeling

    NASA Astrophysics Data System (ADS)

    Yoon, H.; Dewers, T. A.

    2012-12-01

    Accurate prediction of coupled geophysical and chemical processes at the pore scale requires realistic representation of pore structures. This is especially true for chalk materials, where pore networks are small and complex, and often characterized at sub-micron scale. Common techniques such as X-ray microtomography, microscopic imaging, or mercury intrusion porosimetry often show a limit on determining pore throat distributions and seal analysis of such fine-grained rocks. Focused ion beam-scanning electron microscope (FIB-SEM) and laser scanning confocal microscopy methods are used for 3D imaging of nanometer-to-micron scale microcrack and pore distributions in samples of the Cretaceous Selma Group Chalk. The Selma Chalk is considered the seal for oil and gas fields in the Mississippi Interior Salt Basin and a proposed regional-scale seal identified for CO2 sequestration sites. A series of image analysis techniques is used to process raw images in order to recover both nano-scale pore structure and continuous fracture networks. We apply 3D imaging techniques in interpreting FIB-SEM binary data for characterizing geometric pore body and throat distributions and other topological properties, and lattice-Boltzmann method (LBM) for obtaining permeability at several different scales. In particular, comparison of primary flow paths obtained from 3D image analysis and LBM demonstrates that image analysis results may have too many equally plausible flow paths, compared to LBM results. Upscaling of permeability and LB multiphase flow results with image dataset will be discussed with emphasis on understanding microfracture-matrix interaction during multiphase flow, and seal analysis for geologic CO2 storage. This material is based upon work supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001114

  2. High frequency seismic monitoring of debris flows at Chalk Cliffs (CO), USA

    NASA Astrophysics Data System (ADS)

    Coviello, Velio; Kean, Jason; Smith, Joel; Coe, Jeffrey; Arattano, Massimo; McCoy, Scott

    2015-04-01

    A growing number of studies adopt passive seismic monitoring techniques to investigate slope instabilities and landslide processes. These techniques are attractive and convenient because large areas can be monitored from a safe distance. This is particularly true when the phenomena under investigation are rapid and infrequent mass movements like debris flows. Different types of devices are used to monitor debris flow processes, but among them ground vibration detectors (GVDs) present several, specific advantages that encourage their use. These advantages include: (i) the possibility to be installed outside the channel bed, (ii) the high adaptability to different and harsh field conditions, and (iii) the capability to detect the debris flow front arrival tens of seconds earlier than contact and stage sensors. Ground vibration data can provide relevant information on the dynamics of debris flows such as timing and velocity of the main surges. However, the processing of the raw seismic signal is usually needed, both to obtain a more effective representation of waveforms and to decrease the amount of data that need to be recorded and analyzed. With this objective, the methods of Amplitude and Impulses are commonly adopted to transform the raw signal to a 1-Hz signal that allows for a more useful representation of the phenomenon. In that way, peaks and other features become more visible and comparable with data obtained from other monitoring devices. In this work, we present the first debris flows seismic recordings gathered in the Chalk Cliffs instrumented basin, central Colorado, USA. In May 2014, two 4.5-Hz, three-axial geophones were installed in the upper part of the catchment. Seismic data are sampled at 333 Hz and then recorded by a standalone recording unit. One geophone is directly installed on bedrock, the other one mounted on a 1-m boulder partially buried in colluvium. This latter sensor integrates a heavily instrumented cross-section consisting of a 225 cm2

  3. Porosity and permeability development in compacting chalks during flooding of nonequilibrium brines: Insights from long-term experiment

    NASA Astrophysics Data System (ADS)

    Nermoen, Anders; Korsnes, Reidar I.; Hiorth, Aksel; Madland, Merete V.

    2015-05-01

    We report the complete chemical alteration of a Liège outcrop chalk core resulting from a 1072 flow-through experiment performed during mechanical compaction at 130°C. Chemical rock-fluid interactions alter the volumetric strain, porosity, and permeability in a nontrivial way. The porosity reduced only from 41.32% to 40.14%, even though the plug compacted more than 25%. We present a novel analysis of the experimental data, which demonstrates that the geochemical alteration does not conserve the volume of the solids, and therefore, the strain is partitioned additively into a pore volume and solid volume component. At stresses beyond yield, the observed deformation can be explained by grain reorganization reducing the pore space between grains and solid volume changes from the rock-fluid interactions. The mechanical and chemical effects are discussed in relation to the observed permeability development.

  4. Mycorrhizal symbiosis effects on growth of chalk false-brome (Brachypodium pinnatum) are dependent on the environmental light regime.

    PubMed

    Füzy, Anna; Bothe, Hermann; Molnár, Edit; Biró, Borbála

    2014-03-01

    AMF (arbuscular mycorrhizal fungi) colonization of the grass chalk false-brome (Brachypodium pinnatum (L.) P. B.) was studied in selected habitats under spatially different light regimes: (a) shade condition under oak trees, (b) half shade in a shrubby area and (c) full-sun conditions on unshaded grassland. This study assessed the variations in AMF colonization of the grass dependent on the light supply in field habitats. Soil, root and shoot samples were collected four times during the vegetation period (in June, July, September and October). Root colonization, root and shoot biomass as well as soil water content were determined. The highest rate of AMF colonization was detected in June under half-sun and full-sun conditions, where about 50% of the roots were colonized. The average amount of arbuscules was less than 20% in the roots at the three sites, with the highest number of arbuscules in June, under half-sun and full-sun conditions, however, not under the trees. Overall, best mycorrhizal colonization occurred during summer, and its rate decreased in autumn. This tendency inversely correlated with the amount of precipitation, and thus with the water content of soils. The high colonization rate of the examined root samples, and also its seasonal fluctuation, might reflect the importance of the symbiosis where inorganic nutrients and water are the growth-limiting factors. The marginal AMF colonization of chalk false-brome under shade conditions indicates that plants do not use AMF under all stress conditions. When low light limits photosynthesis and thus growth of the plants, they dispense with the colonization of AMF in order to save the expenditure of organic carbon.

  5. Modeling of ground-water flow in subsurface Austin Chalk and Taylor marl in Ellis County, Texas, near the superconducting super collider site

    SciTech Connect

    Mace, R.E. . Bureau of Economic Geology)

    1993-02-01

    Numerical models are useful tools for developing an understanding of ground-water flow in sparsely characterized low-permeability aquifers. Finite-difference, cross-sectional models of Cretaceous chalk and marl formations near the Superconducting Super Collider (SSC) were constructed using MODFLOW to evaluate ground-water circulation paths and travel times. Weathered and fractured zones with enhanced permeability were included to assess the effect these features had on flow paths and times. Pump tests, slug tests, packer tests, core tests, and estimates were used to define hydraulic properties for model input. The model was calibrated with water-level data from monitor wells and from wire-line piezometers near a test shaft excavated by the SSC project. A ratio of vertical-to-horizontal permeability of 0.0085 was estimated through model calibration. A chalk-to-marl permeability ratio of 18 was needed to reproduce artesian head in a well completed in chalk beneath marl. Hydraulic head distributions and ground-water flow paths reflected local, intermediate, and regional flow systems with recharge beneath upland surface-water divides and discharge in valleys. Most of the flow (99%) occurred in the weathered zone, with average residence times of 5 to 10 years. Residence time in unweathered chalk bedrock was substantially longer, at an average of 1.7 Ma. As expected, the model demonstrated that deep and rapid ground-water circulation might occur in fracture zones. Particle paths calculated using MODPATH showed that ground-water travel times from recharge areas to the SSC subsurface facilities might be 20 to 60 years where flow is through fracture zones.

  6. River meanders

    USGS Publications Warehouse

    Leopold, Luna Bergere; Langbein, Walter Basil

    1966-01-01

    The striking geometric regularity of a winding river is no accident. Meanders appear to be the form in which a river does the least work in turning; hence they are the most probable form a river can take

  7. Area balance and strain in an extensional fault system: Strategies for improved oil recovery in fractured chalk, Gilbertown Field, southwestern Alabama. Final report, March 1996--September 1998

    SciTech Connect

    Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Carroll, R.E.; Groshong, R.H.; Jin, G.

    1998-12-01

    This project was designed to analyze the structure of Mesozoic and Tertiary strata in Gilbertown Field and adjacent areas to suggest ways in which oil recovery can be improved. The Eutaw Formation comprises 7 major flow units and is dominated by low-resistivity, low-contrast play that is difficult to characterize quantitatively. Selma chalk produces strictly from fault-related fractures that were mineralized as warm fluid migrated from deep sources. Resistivity, dipmeter, and fracture identification logs corroborate that deformation is concentrated in the hanging-wall drag zones. New area balancing techniques were developed to characterize growth strata and confirm that strain is concentrated in hanging-wall drag zones. Curvature analysis indicates that the faults contain numerous fault bends that influence fracture distribution. Eutaw oil is produced strictly from footwall uplifts, whereas Selma oil is produced from fault-related fractures. Clay smear and mineralization may be significant trapping mechanisms in the Eutaw Formation. The critical seal for Selma reservoirs, by contrast, is where Tertiary clay in the hanging wall is juxtaposed with poorly fractured Selma chalk in the footwall. Gilbertown Field can be revitalized by infill drilling and recompletion of existing wells. Directional drilling may be a viable technique for recovering untapped oil from Selma chalk. Revitalization is now underway, and the first new production wells since 1985 are being drilled in the western part of the field.

  8. Sedimentology and carbon-isotope stratigraphy of the Late Cretaceous Chalk Group in the Höllviken-1 core (SW Sweden)

    NASA Astrophysics Data System (ADS)

    Bøttger, Dorthe; Thibault, Nicolas; Anderskouv, Kresten

    2016-04-01

    The Höllviken-1 borehole is situated on the Skåne peninsula (SW Sweden) which was part of the Danish Basin in the Late Cretaceous. 1415 meters have been cored among which ca. 1100 meters cover the complete Upper Cretaceous to lower Danian Chalk Group. Besides the publication of a synthetic log and detailed foraminifer biozonation, supplemented by a number of rare macrofossil findings and description of a number of foraminifer holotypes (Brötzen, 1944), very few studies of the core have actually been performed, since the mid 1940s. A new project has thus been undertaken aiming at improving the stratigraphy of the Chalk Group in the Höllviken-1 core. The data presented here comprise the description of the interval 837-489 m covering a large part of the Campanian and the lower Maastrichtian. Two intervals with the presence of sand are noted in the Campanian and two intervals showing possibly progradational sequences of arenaceous marls to sand are present in the Maastrichtian. The purpose of this new study is to revise the foraminifer biostratigraphy of Brötzen and complement it with high-resolution carbon-isotope stratigraphy in order to establish a new age-model for the core and better constrain the timing of siliciclastic input into the Danish Basin. In addition, high-resolution sedimentological data will be used as a preliminary test for cyclostratigraphy of the chalk-marl intervals.

  9. Overview of the Government of Canada Nuclear Legacy Liabilities Program - 13551

    SciTech Connect

    Metcalfe, D.; McCauley, D.; Miller, J.; Brooks, S.

    2013-07-01

    Nuclear legacy liabilities have resulted from more than 60 years of nuclear research and development carried out on behalf of Canada. The liabilities are located at Atomic Energy of Canada Limited's (AECL) Chalk River Laboratories in Ontario and Whiteshell Laboratories in Manitoba, as well as three shutdown prototype reactors in Ontario and Quebec that are being maintained in a safe storage state. Estimated at about $7.4 billion (current day dollars), these liabilities consist of disused nuclear facilities and associated infrastructure, a wide variety of buried and stored waste, and contaminated lands. In 2006, the Government of Canada adopted a long-term strategy to deal with the nuclear legacy liabilities and initiated a five-year, $520 million start-up phase, thereby creating the Nuclear Legacy Liabilities Program (NLLP). The Government of Canada renewed the NLLP in 2011 with a $439-million three-year second phase that ends March 31, 2014. The projects and activities carried out under the Program focus on infrastructure decommissioning, environmental restoration, improving the management of legacy radioactive waste, and advancing the long-term strategy. The NLLP is being implemented through a Memorandum of Understanding between Natural Resources Canada (NRCan) and AECL whereby NRCan is responsible for policy direction and oversight, including control of funding, and AECL is responsible for implementing the program of work and holding and administering all licences, facilities and lands. (authors)

  10. Infiltration processes in karstic chalk investigated through a spatial analysis of the geochemical properties of the groundwater: The effect of the superficial layer of clay-with-flints

    NASA Astrophysics Data System (ADS)

    Valdes, Danièle; Dupont, Jean-Paul; Laignel, Benoît; Slimani, Smaïl; Delbart, Célestine

    2014-11-01

    In the Paris Basin in Upper Normandy (France), the chalk plateaus are covered with thick deposits of loess and clay-with-flints, from a few meters to approximately 40 m thick locally. A perched groundwater is sometimes observed in the superficial layers in which evapotranspiration processes seem to occur. This study's objective was to understand the effects of the thick clay-with-flints layers on the infiltration processes. To achieve this, we adopted a spatial approach comparing the maps of the geochemical properties of the Chalk groundwater and the maps of the thickness of clay-with-flints. The French national groundwater database, ADES (Accès aux Données des Eaux, BRGM), provided the mean geochemical properties in the Chalk aquifer of Upper Normandy. This database was used to prepare maps of the environmental tracers: Ca2+, HCO3-, Mg2+, Cl-, Na+, NO3-, and SO42. The data are spatially well organized. Using principal component analysis (PCA), these maps were compared with the maps of the thickness of clay-with-flints. A focus on the coastal basins (northern Upper Normandy) shows a very strong spatial correlation between the maps of clay-with-flints thickness and all of the maps of the major ions. The thickness of clay-with-flints is negatively correlated with the autochthonous ions (HCO3- and Ca2+) and is positively correlated with the allochthonous ions (Cl-, Na+, SO42-, and NO3-). These results highlight that the thickness of clay-with-flints controls recharge. Two types of infiltration processes are proposed: (1) Thicker clay-with-flints allows storage in the perched groundwater, which allows evapotranspiration, resulting in high concentrations of allochthonous ions and a decrease in the dissolution potential of water and low concentrations of autochthonous ions. The infiltration of the perched groundwater is thus delayed and concentrated. (2) Thinner clay-with-flints causes the infiltration to be more diffuse, with low evapotranspiration and thus low

  11. How spatial variations of chalk groundwater geochemistry are related to superficial formations and infiltration processes of unsaturated zone (quarry of Saint Martin le Noeud, France)

    NASA Astrophysics Data System (ADS)

    Barhoum, Sarah; Valdès-Lao, Danièle; Guérin, Roger; Gombert, Philippe

    2013-04-01

    Chalk is complex because of its dual porosity and because of superficial layers more or less thick and more or less permeable. Furthermore there is few knowledge in understanding of groundwater infiltration and dissolution processes in the chalk unsaturated zone (UZ). The role of superficial formations has to be studied especially. The experimental site is an ancient underground quarry of chalk which extends over 1200 m long and 150 m wide (30 m depth) in Saint Martin le Noeud, south of Beauvais, France. This quarry is particularly interesting to study infiltration and dissolution processes indeed this site allows to access to the interface between the unsaturated zone and the saturated zone. Water percolates from the top of the quarry more or less depending on the season. Water table outcrops in the cave and makes about 20 underground lakes. Above the quarry chalk is covered clay-with-flints (CWF) and loess, in surface there are cultivated crops fields. On the first year of the study, physicochemical parameters: temperature, depth, pH, conductivity were recorded in seven lakes with high frequency (every hour). During the same period we sampled the 20 lakes water every month to measure major ions. During this sampling period, percolation was not sufficient to collect percolated water. Results of underground GPS, electric resistivity tomography and observations of three borehole showed that thickness unsaturated zone and that the thicknesses of the superficial formations vary a lot spatially. Three interesting points (separated by less than 1 km) are presented: the above the Pedro lake (25 m of UZ, a few cm of CWF), above the Stalactites lake (30 m of UZ, more than 2.40 m of CWF); above the Blue lake (35 m depth, 60 cm of CWF). First results of chemistry showed that the temporal variation is very low during the first year but there spatial variation is very important at quarry scale. The geochemistry of the lakes are very different: HCO3- varies from 100 to 250mg

  12. Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 1, in-situ measurements of flow dynamics, tracer particle movement and video imagery from the summer of 2009

    USGS Publications Warehouse

    McCoy, Scott W.; Coe, Jeffrey A.; Kean, Jason W.; Tucker, Greg E.; Staley, Dennis M.; Wasklewicz, Thad A.

    2011-01-01

    Debris flows initiated by surface-water runoff during short duration, moderate- to high-intensity rainfall are common in steep, rocky, and sparsely vegetated terrain. Yet large uncertainties remain about the potential for a flow to grow through entrainment of loose debris, which make formulation of accurate mechanical models of debris-flow routing difficult. Using a combination of in situ measurements of debris flow dynamics, video imagery, tracer rocks implanted with passive integrated transponders (PIT) and pre- and post-flow 2-cm resolution digital terrain models (terrain data presented in a companion paper by STALEY et alii, 2011), we investigated the entrainment and transport response of debris flows at Chalk Cliffs, CO, USA. Four monitored events during the summer of 2009 all initiated from surface-water runoff, generally less than an hour after the first measurable rain. Despite reach-scale morphology that remained relatively constant, the four flow events displayed a range of responses, from long-runout flows that entrained significant amounts of channel sediment and dammed the main-stem river, to smaller, short-runout flows that were primarily depositional in the upper basin. Tracer-rock travel-distance distributions for these events were bimodal; particles either remained immobile or they travelled the entire length of the catchment. The long-runout, large-entrainment flow differed from the other smaller flows by the following controlling factors: peak 10-minute rain intensity; duration of significant flow in the channel; and to a lesser extent, peak surge depth and velocity. Our growing database of natural debris-flow events can be used to develop linkages between observed debris-flow transport and entrainment responses and the controlling rainstorm characteristics and flow properties.

  13. Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds

    PubMed Central

    Bell, Alyssa; Chiappe, Luis M.

    2015-01-01

    The Smoky Hill Member of the Niobrara Chalk in Kansas (USA) has yielded the remains of numerous members of the Hesperornithiformes, toothed diving birds from the late Early to Late Cretaceous. This study presents a new taxon of hesperornithiform from the Smoky Hill Member, Fumicollis hoffmani, the holotype of which is among the more complete hesperornithiform skeletons. Fumicollis has a unique combination of primitive (e.g. proximal and distal ends of femur not expanded, elongate pre-acetabular ilium, small and pyramidal patella) and derived (e.g. dorsal ridge on metatarsal IV, plantarly-projected curve in the distal shaft of phalanx III:1) hesperornithiform characters, suggesting it was more specialized than small hesperornithiforms like Baptornis advenus but not as highly derived as the larger Hesperornis regalis. The identification of Fumicollis highlights once again the significant diversity of hesperornithiforms that existed in the Late Cretaceous Western Interior Seaway. This diversity points to the existence of a complex ecosystem, perhaps with a high degree of niche partitioning, as indicated by the varying degrees of diving specializations among these birds. PMID:26580402

  14. Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds.

    PubMed

    Bell, Alyssa; Chiappe, Luis M

    2015-01-01

    The Smoky Hill Member of the Niobrara Chalk in Kansas (USA) has yielded the remains of numerous members of the Hesperornithiformes, toothed diving birds from the late Early to Late Cretaceous. This study presents a new taxon of hesperornithiform from the Smoky Hill Member, Fumicollis hoffmani, the holotype of which is among the more complete hesperornithiform skeletons. Fumicollis has a unique combination of primitive (e.g. proximal and distal ends of femur not expanded, elongate pre-acetabular ilium, small and pyramidal patella) and derived (e.g. dorsal ridge on metatarsal IV, plantarly-projected curve in the distal shaft of phalanx III:1) hesperornithiform characters, suggesting it was more specialized than small hesperornithiforms like Baptornis advenus but not as highly derived as the larger Hesperornis regalis. The identification of Fumicollis highlights once again the significant diversity of hesperornithiforms that existed in the Late Cretaceous Western Interior Seaway. This diversity points to the existence of a complex ecosystem, perhaps with a high degree of niche partitioning, as indicated by the varying degrees of diving specializations among these birds.

  15. Projecting impacts of climate change on hydrological conditions and biotic responses in a chalk valley riparian wetland

    NASA Astrophysics Data System (ADS)

    House, A. R.; Thompson, J. R.; Acreman, M. C.

    2016-03-01

    Projected changes in climate are likely to substantially impact wetland hydrological conditions that will in turn have implications for wetland ecology. Assessing ecohydrological impacts of climate change requires models that can accurately simulate water levels at the fine-scale resolution to which species and communities respond. Hydrological conditions within the Lambourn Observatory at Boxford, Berkshire, UK were simulated using the physically based, distributed model MIKE SHE, calibrated to contemporary surface and groundwater levels. The site is a 10 ha lowland riparian wetland where complex geological conditions and channel management exert strong influences on the hydrological regime. Projected changes in precipitation, potential evapotranspiration, channel discharge and groundwater level were derived from the UK Climate Projections 2009 ensemble of climate models for the 2080s under different scenarios. Hydrological impacts of climate change differ through the wetland over short distances depending on the degree of groundwater/surface-water interaction. Discrete areas of groundwater upwelling are associated with an exaggerated response of water levels to climate change compared to non-upwelling areas. These are coincident with regions where a weathered chalk layer, which otherwise separates two main aquifers, is absent. Simulated water levels were linked to requirements of the MG8 plant community and Desmoulin's whorl snail (Vertigo moulinsiana) for which the site is designated. Impacts on each are shown to differ spatially and in line with hydrological impacts. Differences in water level requirements for this vegetation community and single species highlight the need for separate management strategies in distinct areas of the wetland.

  16. Diagnosing hydrological limitations of a land surface model: application of JULES to a deep-groundwater chalk basin

    NASA Astrophysics Data System (ADS)

    Le Vine, N.; Butler, A.; McIntyre, N.; Jackson, C.

    2016-01-01

    Land surface models (LSMs) are prospective starting points to develop a global hyper-resolution model of the terrestrial water, energy, and biogeochemical cycles. However, there are some fundamental limitations of LSMs related to how meaningfully hydrological fluxes and stores are represented. A diagnostic approach to model evaluation and improvement is taken here that exploits hydrological expert knowledge to detect LSM inadequacies through consideration of the major behavioural functions of a hydrological system: overall water balance, vertical water redistribution in the unsaturated zone, temporal water redistribution, and spatial water redistribution over the catchment's groundwater and surface-water systems. Three types of information are utilized to improve the model's hydrology: (a) observations, (b) information about expected response from regionalized data, and (c) information from an independent physics-based model. The study considers the JULES (Joint UK Land Environmental Simulator) LSM applied to a deep-groundwater chalk catchment in the UK. The diagnosed hydrological limitations and the proposed ways to address them are indicative of the challenges faced while transitioning to a global high resolution model of the water cycle.

  17. The benthic macrofauna from the Lower Maastrichtian chalk of Kronsmoor (northern Germany, Saturn quarry): taxonomic outline and palaeoecologic implications

    NASA Astrophysics Data System (ADS)

    Engelke, Julia; Esser, Klaus J. K.; Linnert, Christian; Mutterlose, Jörg; Wilmsen, Markus

    2016-12-01

    The benthic macroinvertebrates of the Lower Maastrichtian chalk of Saturn quarry at Kronsmoor (northern Germany) have been studied taxonomically based on more than 1,000 specimens. Two successive benthic macrofossil assemblages were recognised: the lower interval in the upper part of the Kronsmoor Formation (Belemnella obtusa Zone) is characterized by low abundances of macroinvertebrates while the upper interval in the uppermost Kronsmoor and lowermost Hemmoor formations (lower to middle Belemnella sumensis Zone) shows a high macroinvertebrate abundance (eight times more than in the B. obtusa Zone) and a conspicuous dominance of brachiopods. The palaeoecological analysis of these two assemblages indicates the presence of eight different guilds, of which epifaunal suspension feeders (fixo-sessile and libero-sessile guilds), comprising approximately half of the trophic nucleus of the lower interval, increased to a dominant 86% in the upper interval, including a considerable proportion of rhynchonelliform brachiopods. It is tempting to relate this shift from the lower to the upper interval to an increase in nutrient supply and/or a shallowing of the depositional environment but further data including geochemical proxies are needed to fully understand the macrofossil distribution patterns in the Lower Maastrichtian of Kronsmoor.

  18. Phosphorus dynamics and productivity in a sewage-impacted lowland chalk stream

    NASA Astrophysics Data System (ADS)

    Palmer-Felgate, Elizabeth J.; Jarvie, Helen P.; Williams, Richard J.; Mortimer, Robert J. G.; Loewenthal, Matthew; Neal, Colin

    2008-03-01

    SummaryHourly in situ phosphorus, conductivity, turbidity, dissolved oxygen, pH, and chlorophyll measurements were collected from January 2004 to November 2006 for the River Kennet, 2 km downstream of a sewage effluent inlet. Excess carbon dioxide pressure (EpCO 2) was calculated from continuous pH and spot alkalinity measurements. EpCO 2 and dissolved oxygen were used to estimate rates of photosynthesis and respiration. These parameters were examined alongside flow, water temperature and solar radiation to explore controls on phosphorus dynamics and in-stream productivity. Diurnal, event and seasonal patterns were observed in phosphorus concentrations. The diurnal and seasonal variations appeared to be related to the upstream sewage treatment works. The event patterns coincided with periods of high flow, and were attributed to diffuse sources. Chlorophyll behaved independently of phosphorus concentration and returned to baseline levels before photosynthesis rate. This indicated that, during the period of study, in-stream productivity was primarily controlled by aquatic plants other than phytoplankton.

  19. Neogene paleogeography of western Snake River plain, Idaho and Oregon

    SciTech Connect

    Porter, M.L.; Middleton, L.T.

    1984-04-01

    Analysis of Miocene through Pleistocene siliciclastic and volcaniclastic sequences in the western Snake River Plain of Idaho and Oregon allows detailed paleogeographic reconstruction of sedimentation associated with the development of a rapidly subsiding continental basin. Extensional tectonism was accompanied by voluminous outpourings of basaltic and silicic volcanic material. These in turn were reworked basinward by marginal alluvial fan-braided stream networks into basin-center fluviolacustrine systems. Episodic influxes of both felsic and basaltic tephra are recorded in fossiliferous lacustrine silt and claystones of the Poison Creek and Chalk Hills Formations, radiometrically bracketed between 12.5 to 5 m.y.B.P. Basinward-fining facies indicate deposition in the large lacustrine complex fed by at least 2 major fluvial systems. Complex interfingering of coarse-grained strandline deposits with offshore fine-grained sediments suggests repeated expansion and contraction of the lake system and record the dynamic interplay between basin tectonism and sedimentation.

  20. Origin of nickel in water solution of the chalk aquifer in the north of France and influence of geochemical factors

    NASA Astrophysics Data System (ADS)

    Bernard, Daniel; El Khattabi, Jamal; Lefevre, Emilie; Serhal, Hani; Bastin-Lacherez, Sabine; Shahrour, Isam

    2008-01-01

    In the north of France, high registers of nickel are sometimes recorded within the chalk aquifer. In a confined context, the presence of pyrite in the covering clays or in the marcasite nodules encrusted in the clay may constitute a natural source of trace metals. With an objective of sanitary control, the limits of chemical contents regulating the quality of water destined for human consumption have been lowered by the European Framework Directive in the field of water policy (2000/60/EC). As a result, nickel limits have been reduced from 50 to 20 μg/l. The analyses, carried out on three water catchment fields in our area of study, were centred on variable parameters (Eh, O2(d), pH, Conductivity, T°), major elements (SO4, NO3) and metals (Fe, Ni, Mn, Co). The acquired data enabled us to identify from one hand, the conditions which are presented within the site, special thanks to the evolution of nitrate and iron contents and on the other hand, the natural origin (geological) of nickel for two of the three sites studied based essentially on the evaluation of the Nickel/Cobalt ratio. Thus, on the first site, the evolution of nickel content and nitrate content showed the influence of the phenomenon of denitrification on the re-mobilisation of the nickel. Whereas on the second site, a high variation of total iron content and oxygen dissolved in solution highlighted a particular phenomenon of oxidation of the pyrite through molecular oxygen. Finally, the correlation with the sulphates clearly showed behaviour of the nickel, once released, that was entirely dependent on the phenomenon of adsorption on the iron and manganese hydroxides.

  1. Large scale hot water migration systems around salt diapirs in the Danish Central Trough and their impact on diagenesis of chalk reservoirs

    NASA Astrophysics Data System (ADS)

    Jensenius, Jørgen; Munksgaard, Niels C.

    1989-01-01

    Fracture filling calcite from the piercement fields of East Rosa, Skjold, Rolf, North Arne, Nils and Vagn (directly underlain by salt diapirs) and the dome field Dan (overlying a deep seated salt structure) have been studied by fluorescence and cathodoluminiscence microscopy, fluid inclusion microthermometry and carbon and oxygen isotopes. The carbon and oxygen isotope compositions of the reservoir matrix chalk have also been measured. The temperature estimates obtained from fluid inclusion data suggest that the fracture filling calcite of the piercement fields precipitated during hot water flushing of the reservoirs. The flushing system only existed around the salt diapirs and was probably related to expulsion of overpressured fluid from the surrounding sediments. The thermal anomaly and the faults associated with the diapirs probably were important factors in focusing the ascending water. By combining fluid inclusion thermometry with O isotope data for the fracture filling calcites ranges of O isotopic values of the flushing water are deduced: in Skjold, Rolf, North Arne, Nils and Vagn: δ18O = - 1 to + 7%. SMOW, values typical of sedimentary porewater of sea water origin; in East Rosa: δ18O = - 4 and + 4%. SMOW, which combined with data on fluid inclusion salinities suggest that the flushing waters were responsible for substantial salt dissolution. Lower δ18O values with shallower depth of burial suggest that the porosity of chalk in the shallower fields was more severely reduced by calcite cementation during the flushing event than in the deeper fields. In the case of North Arne, Nils, Vagn and Dan, δ 13C values of the fracture filling calcites are similar to those of normal chalk (0.5 to 3.5%.). However, calcites from Rolf, Skjold and East Rosa are depleted by - 1.8, - 6.2 and - 16.7%., respectively. Only in East Rosa is the matrix chalk itself depleted in 13C (range: - 2.0 to + 0.7%.). The low δ 13C values are interpreted as the result of biodegration

  2. Charles River

    EPA Pesticide Factsheets

    Information on the efforts of the US EPA, the Commonwealth of Massachusetts, the municipalities within the Charles River Watershed and nongovernmental organizations to improve the water quality of the Charles River.

  3. Westward extension of the Devils River uplift Implications for the Paleozoic evolution of the southern margin of North America

    NASA Astrophysics Data System (ADS)

    Ewing, Thomas E.

    1985-06-01

    The Devils River uplift is inferred to continue westward into Trans-Pecos Texas. Both the known Devils River uplift and the Tascotal uplift are bounded on the north by east-west fault zones (Chalk Draw and Carta Valley fault zones) separating them from Late Pennsylvanian clastic foredeep basins (Marfa and Val Verde basins). The exposed, much-shortened Marathon thrust belt may have been emplaced in the earliest Permian by gravity gliding. Meager evidence suggests that the Devils River block represents a Cambrian or Infracambrian rift and that the uplift is an aulacogen. The early Cambrian continental margin probably continued southwest into Mexico but has been displaced by Mesozoic left-lateral movement.

  4. Amazon River

    Atmospheric Science Data Center

    2013-04-17

    article title:  Mouth of the Amazon River     View ... of the world's mightiest rivers. This image of the Amazon's mouth was captured by the Multi-angle Imaging SpectroRadiometer (MISR) ... available at JPL September 8, 2000 - Mouth of the mighty Amazon River. project:  MISR ...

  5. Area balance and strain in an extensional fault system: Strategies for improved oil recovery in fractured chalk, Gilbertown Field, southwestern Alabama. Annual report, March 1996--March 1997

    SciTech Connect

    Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Groshong, R.H.

    1997-08-01

    Gilbertown Field is the oldest oil field in Alabama and produces oil from chalk of the Upper Cretaceous Selma Group and from sandstone of the Eutaw Formation along the southern margin of the Gilbertown fault system. Most of the field has been in primary recovery since establishment, but production has declined to marginally economic levels. This investigation applies advanced geologic concepts designed to aid implementation of improved recovery programs. The Gilbertown fault system is detached at the base of Jurassic salt. The fault system began forming as a half graben and evolved in to a full graben by the Late Cretaceous. Conventional trapping mechanisms are effective in Eutaw sandstone, whereas oil in Selma chalk is trapped in faults and fault-related fractures. Burial modeling establishes that the subsidence history of the Gilbertown area is typical of extensional basins and includes a major component of sediment loading and compaction. Surface mapping and fracture analysis indicate that faults offset strata as young as Miocene and that joints may be related to regional uplift postdating fault movement. Preliminary balanced structural models of the Gilbertown fault system indicate that synsedimentary growth factors need to be incorporated into the basic equations of area balance to model strain and predict fractures in Selma and Eutaw reservoirs.

  6. Phosphorus sources, speciation and dynamics in the lowland eutrophic River Kennet, UK.

    PubMed

    Jarvi, Helen P; Neal, Colin; Williams, Richard J; Neal, Margaret; Wickham, Heather D; Hill, Linda K; Wade, Andrew J; Warwick, Alan; White, John

    2002-01-23

    This paper examines the behaviour of phosphorus (P) in a lowland chalk (Cretaceous-age) stream, the upper River Kennet in southern England, which has been subject to P remediation by tertiary treatment at the major sewage treatment works in the area. The effects of treatment are examined in relation to boron, a conservative tracer of sewage effluent and in terms of the relative contributions of soluble reactive phosphorus (SRP) loads from point and diffuse sources, and in-stream SRP loads. These results indicate a baseline reduction in in-stream SRP concentrations immediately following P-treatment of approximately 72%. Subsequent high flows result in a greater contribution of diffuse inputs and increases in SRP levels relative to the initial post-treatment period. The dynamics of SRP and particulate phosphorus (PP) are examined under a wide range of river flow conditions. Given the flashy nature of near-surface runoff in the River Kennet, sub-weekly (daily automated) sampling was used to examine the dynamics in SRP and PP concentrations in response to storm events. Simple empirical models linking weekly SRP concentrations with flow were developed. The empirical models were successfully applied to the daily data, to partition TP measurements and provide an estimate of daily SRP and PP concentrations. Mass balance studies were used to examine net gains and losses along the experimental river reach and indicate large net losses (up to 60%) during the extreme low flows and high SRP concentrations prior to P-treatment, which may be linked to extensive epiphytic growth. Phosphorus dynamics and response to P-treatment are discussed in relation to hydrological controls in permeable chalk catchments and wider implications for eutrophication management are examined.

  7. Observations and Experiments on Carbonate Secretion in "Calcite Seas": Why Massive Chalk Deposits Formed in Late Cretaceous Time

    NASA Astrophysics Data System (ADS)

    Stanley, S. M.; Ries, J. B.; Hardie, L. A.

    2003-12-01

    It is now well-established that oscillations in the Mg/Ca ratio of seawater, driven by changes in spreading rates along mid-ocean ridges, have determined the mineralogy of nonskeletal marine carbonate precipitation throughout earth history. Low-Mg calcite has formed at Mg/Ca ratios < 2 ("calcite seas"), and aragonite has formed at ratios > 2 ("aragonite seas"). High-Mg calcite (mole % Mg > 4) has formed by itself at Mg/Ca ratios of 1-2, and along with aragonite at ratios above 2. We report here on experiments rooted in the paleontological observation that the carbonate mineralogy of major reef-building and sediment-producing organisms has tended to correspond to that of nonskeletal precipitates throughout Phanerozoic time. Earlier experiments showed that, with changes in the Mg/Ca ratio of ambient seawater, the Mg content of calcite in coralline algae varies like that of nonskeletal calcite precipitates. New experiments reveal that many kinds of calcite-secreting marine animals exhibit similar mineralogical trends, but with varying partition coefficients. Other experiments address the effects of seawater chemistry on productivity. One can predict that secretion of calcium carbonate will facilitate growth of algae because it releases carbon dioxide that can be used in photosynthesis. Indeed, we found that Halimeda, a major producer of aragonite sediment in present-day aragonite seas, grows less rapidly when living at ambient Mg/Ca ratios below the modern marine level of 5.2. Conversely, calcareous nannoplankton, which secrete calcite, become much more productive when ambient Mg/Ca ratios are below unity and associated concentrations of Ca are high. Such conditons characterized the extreme calcite seas of Late Cretaceous time, when nannoplankton formed massive chalk deposits throughout the world. Thus, we attribute the formation of these deposits, which gave the Cretaceous Period its name, to seawater chemistry. Calcareous nannoplankton in modern seas are adapted to

  8. Mapping of groundwater potential zones in Salem Chalk Hills, Tamil Nadu, India, using remote sensing and GIS techniques.

    PubMed

    Thilagavathi, N; Subramani, T; Suresh, M; Karunanidhi, D

    2015-04-01

    This study proposes to introduce the remote sensing and geographic information system (GIS) techniques in mapping the groundwater potential zones. Remote sensing and GIS techniques have been used to map the groundwater potential zones in Salem Chalk Hills, Tamil Nadu, India. Charnockites and fissile hornblende biotite gneiss are the major rock types in this region. Dunites and peridodites are the ultramafic rocks which cut across the foliation planes of the gneisses and are highly weathered. It comprises magnesite and chromite deposits which are excavated by five mining companies by adopting bench mining. The thickness of weathered and fracture zone varies from 2.2 to 50 m in gneissic formation and 5.8 to 55 m in charnockite. At the contacts of gneiss and charnockite, the thickness ranges from 9.0 to 90.8 m favoring good groundwater potential. The mine lease area is underlined by fractured and sheared hornblende biotite gneiss where groundwater potential is good. Water catchment tanks in this area of 5 km radius are small to moderate in size and are only seasonal. They remain dry during summer seasons. As perennial water resources are remote, the domestic and agricultural activities in this region depend mainly upon the groundwater resources. The mines are located in gently slope area, and accumulation of water is not observed except in mine pits even during the monsoon period. Therefore, it is essential to map the groundwater potential zones for proper management of the aquifer system. Satellite imageries were also used to extract lineaments, hydrogeomorphic landforms, drainage patterns, and land use, which are the major controlling factors for the occurrence of groundwater. Various thematic layers pertaining to groundwater existence such as geology, geomorphology, land use/land cover, lineament, lineament density, drainage, drainage density, slope, and soil were generated using GIS tools. By integrating all the above thematic layers based on the ranks and

  9. Implementation of agronomical and geochemical modules into a 3D groundwater code for assessing nitrate storage and transport through unconfined Chalk aquifer

    NASA Astrophysics Data System (ADS)

    Picot-Colbeaux, Géraldine; Devau, Nicolas; Thiéry, Dominique; Pettenati, Marie; Surdyk, Nicolas; Parmentier, Marc; Amraoui, Nadia; Crastes de Paulet, François; André, Laurent

    2016-04-01

    Chalk aquifer is the main water resource for domestic water supply in many parts in northern France. In same basin, groundwater is frequently affected by quality problems concerning nitrates. Often close to or above the drinking water standards, nitrate concentration in groundwater is mainly due to historical agriculture practices, combined with leakage and aquifer recharge through the vadose zone. The complexity of processes occurring into such an environment leads to take into account a lot of knowledge on agronomy, geochemistry and hydrogeology in order to understand, model and predict the spatiotemporal evolution of nitrate content and provide a decision support tool for the water producers and stakeholders. To succeed in this challenge, conceptual and numerical models representing accurately the Chalk aquifer specificity need to be developed. A multidisciplinary approach is developed to simulate storage and transport from the ground surface until groundwater. This involves a new agronomic module "NITRATE" (NItrogen TRansfer for Arable soil to groundwaTEr), a soil-crop model allowing to calculate nitrogen mass balance in arable soil, and the "PHREEQC" numerical code for geochemical calculations, both coupled with the 3D transient groundwater numerical code "MARTHE". Otherwise, new development achieved on MARTHE code allows the use of dual porosity and permeability calculations needed in the fissured Chalk aquifer context. This method concerning the integration of existing multi-disciplinary tools is a real challenge to reduce the number of parameters by selecting the relevant equations and simplifying the equations without altering the signal. The robustness and the validity of these numerical developments are tested step by step with several simulations constrained by climate forcing, land use and nitrogen inputs over several decades. In the first time, simulations are performed in a 1D vertical unsaturated soil column for representing experimental nitrates

  10. River restoration

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen; Angermeier, Paul L.; Bledsoe, Brian; Kondolf, G. Mathias; Macdonnell, Larry; Merritt, David M.; Palmer, Margaret A.; Poff, N. Leroy; Tarboton, David

    2005-10-01

    River restoration is at the forefront of applied hydrologic science. However, many river restoration projects are conducted with minimal scientific context. We propose two themes around which a research agenda to advance the scientific basis for river restoration can be built. First, because natural variability is an inherent feature of all river systems, we hypothesize that restoration of process is more likely to succeed than restoration aimed at a fixed end point. Second, because physical, chemical, and biological processes are interconnected in complex ways across watersheds and across timescales, we hypothesize that restoration projects are more likely to be successful in achieving goals if undertaken in the context of entire watersheds. To achieve restoration objectives, the science of river restoration must include (1) an explicit recognition of the known complexities and uncertainties, (2) continued development of a theoretical framework that enables us to identify generalities among river systems and to ask relevant questions, (3) enhancing the science and use of restoration monitoring by measuring the most effective set of variables at the correct scales of measurement, (4) linking science and implementation, and (5) developing methods of restoration that are effective within existing constraints. Key limitations to river restoration include a lack of scientific knowledge of watershed-scale process dynamics, institutional structures that are poorly suited to large-scale adaptive management, and a lack of political support to reestablish delivery of the ecosystem amenities lost through river degradation. This paper outlines an approach for addressing these shortcomings.

  11. Mississippi River

    Atmospheric Science Data Center

    2014-05-15

    article title:  Mississippi River Flooding during Spring 2001   ... 794 x 390 South TIFF: 1024 x 724 The Mississippi River, from its source at Lake Itasca Minnesota to the Gulf of ... lower valley occurred in 1927 and the largest in the upper Mississippi in 1993. In April 2001 another flooding event in the upper ...

  12. Discussing spent nuclear fuel in high school classrooms: addressing public fears through early education

    SciTech Connect

    Winkel, S.; Sullivan, J.; Jones, S.; Sullivan, K.; Hyland, B.; Pencer, J.; Colton, A.

    2013-07-01

    The Inreach program combines the Deep River Science Academy (DRSA) 'learning through research' approach with state of the art communication technology to bring scientific research to high school classrooms. The Inreach program follows the DRSA teaching model where a university student tutor works on a research project with scientific staff at AECL's Chalk River Laboratories. Participating high school classes are located across Canada. The high school students learn about the ongoing research activities via weekly web conferences. In order to engage the students and encourage participation in the conferences, themed exercises linked to the research project are provided to the students. The DRSA's Inreach program uses a cost-effective internet technology to reach a wide audience, in an interactive setting, without anyone leaving their desks or offices. An example Inreach research project is presented here: an investigation of the potential of the Canadian supercritical water cooled reactor (SCWR) concept to burn transuranic elements (Np, Pu, Am, Cm) to reduce the impact of used nuclear fuel. During this project a university student worked with AECL (Atomic Energy of Canada Limited) researchers on technical aspects of the project, and high school students followed their progress and learned about the composition, hazards, and disposition options for used nuclear fuel. Previous projects included the effects of tritium on cellular viability and neutron diffraction measurement of residual stresses in automobile engines.

  13. Nutrient dynamics as indicators of karst processes: Comparison of the Chalk aquifer (Normandy, France) and the Edwards aquifer (Texas, U.S.A.)

    USGS Publications Warehouse

    Mahler, B.J.; Valdes, D.; Musgrove, M.; Massei, N.

    2008-01-01

    Karst aquifers display a range of geologic and geomorphic characteristics in a wide range of climatic and land-use settings; identification of transport dynamics representative of karst aquifers in general could help advance our understanding of these complex systems. To this end, nutrient, turbidity, and major ion dynamics in response to storms were compared at multiple sites in two karst aquifers with contrasting characteristics and settings: the Chalk aquifer (Eure Department, Normandy, France) and the Barton Springs segment of the Edwards Aquifer (Texas, U.S.A.). The Chalk aquifer is typified by high matrix porosity, thick surficial deposits (up to 30??m thick), and agricultural land use; the Barton Springs segment is typified by low matrix porosity, outcropping limestone, and urban land use. Following one to three storms, from 5 to 16 samples from springs and wells were analyzed for major ions, and specific conductance and turbidity were monitored continuously. Comparison of the chemographs indicated some generalized responses, including an increase in turbidity and potassium concentrations and a decrease in major ion and nitrate concentrations with infiltrating storm runoff. Factor analysis of major ions and turbidity revealed strikingly similar behavior of the chemical variables for the two aquifers: The first two factors, explaining more than 75% of the variability, illustrate that dynamics of most major ions (including nitrate) are opposed to those of turbidity and of potassium. The results demonstrate that potassium and nitrate are effective tracers of infiltrating storm runoff and resident ground water, respectively, and the similar results for these two highly contrasting aquifers suggest that the dynamics identified might be applicable to karst systems in general. ?? 2008 Elsevier B.V. All rights reserved.

  14. Simulated maintenance a virtual reality

    SciTech Connect

    Lirvall, P.

    1995-10-01

    The article describes potential applications of personal computer-based virtual reality software. The applications are being investigated by Atomic Energy of Canada Limited`s (AECL) Chalk River Laboratories for the Canadian deuterium-uranium (Candu) reactor. Objectives include: (1) reduction of outage duration and improved safety, (2) cost-effective and safe maintenance of equipment, (3) reduction of exposure times and identification of overexposure situations, (4) cost-effective training in a virtual control room simulator, (5) human factors evaluation of design interface, and (6) visualization of conceptual and detailed designs of critical nuclear field environments. A demonstration model of a typical reactor control room, the use of virtual reality in outage planning, and safety issues are outlined.

  15. The water quality of the River Dun and the Kennet and Avon Canal

    NASA Astrophysics Data System (ADS)

    Neal, Colin; House, W. Alan; Jarvie, Helen P.; Neal, Margaret; Hill, Linda; Wickham, Heather

    2006-10-01

    SummaryThe water quality of the River Dun and associated surface waters (a reservoir, two tributaries of the Dun, the Kennet and Avon Canal and the River Kennet to which the Dun drains) is described for a wide range of major, minor and trace elements. The water quality is determined by inputs from: (a) geologic sources (Ca, Sr concentrations and alkalinity) and (b) contaminant inputs from farming and sewage (Na, Cl, B, soluble reactive phosphorus and nitrate). As river water is mainly supplied from the Chalk aquifer and riparian areas, the water quality variation is damped, but there are occasional storms, where near surface/surface runoff delivers higher nutrient and suspended sediment concentrations, but dilutes determinands derived predominantly from geologic and point sources. River and canal water quality is also modified by in-stream biological processes in spring and summer, which remove nutrients (N, P and Si) and CO 2 from the water, bringing about precipitation of calcium carbonate and thus reductions in Ca concentrations and alkalinity. The biological effects are particularly marked for the Kennet and Avon Canal. The River Dun and Kennet and Avon Canal have been subject to episodic fish-kills and concern has been expressed about the role of event-based resuspension of bed sediments and mobilisation of dredged sediments on dissolved oxygen levels within the river. Therefore, fluvarium experiments on sediment-water interactions were undertaken to examine the potential effects of bed sediment disturbance on dissolved oxygen levels. The results of the fluvarium experiments demonstrate an ecologically-significant 30% reduction in dissolved oxygen levels following bed sediment disturbance. This reduction in DO concentrations was greater than expected from calculations using the measured sediment-oxygen demand. However, it is not clear that the bed sediments are mobilized to sufficient extent in the field for deleterious loss of DO. Indeed, much of the

  16. River Times.

    ERIC Educational Resources Information Center

    Auldridge, Teresa; And Others

    The James River is one of the most precious resources of Virginia. It was the site of the first permanent English settlement in the New World; the power of the water at the Fall Zone was a major factor in the development of Richmond; and the river served as a primary transportation route to the West via the Kanawha Canal. Both the water itself and…

  17. 27 CFR 9.66 - Russian River Valley.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Section 21 and 22 and 27 and 28 and in a straight line to the peak of Chalk Hill on the Healdsburg map. (33) Proceed west from the peak of Chalk Hill in a straight line to the point where Brooks Creek...

  18. 27 CFR 9.66 - Russian River Valley.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Section 21 and 22 and 27 and 28 and in a straight line to the peak of Chalk Hill on the Healdsburg map. (33) Proceed west from the peak of Chalk Hill in a straight line to the point where Brooks Creek...

  19. 27 CFR 9.66 - Russian River Valley.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Section 21 and 22 and 27 and 28 and in a straight line to the peak of Chalk Hill on the Healdsburg map. (33) Proceed west from the peak of Chalk Hill in a straight line to the point where Brooks Creek...

  20. Radionuclide migration in groundwater at a low-level waste disposal site: a comparison of predictive performance modeling versus field observations

    SciTech Connect

    Robertson, D.E. Myers, D.A.; Bergeron, M.P.; Champ, D.R.; Killey, R.W.D.; Moltyaner, G.L.; Young, J.L.

    1985-08-01

    This paper describes a project which is structured to test the concept of modeling a shallow land low-level waste burial site. The project involves a comparison of the actual observed radionuclide migration in groundwaters at a 30-year-old well-monitored field site with the results of predictive transport modeling. The comparison is being conducted as a cooperative program with the Atomic Energy of Canada Ltd. (AECL) at the low-level waste management area at the Chalk River Nuclear Laboratories, Ontario, Canada. A joint PNL-AECL field inviestigation was conducted in 1983 and 1984 to complement the existing extensive data base on actual radionuclide migration. Predictive transport modeling is currently being conducted for this site; first, as if it were a new location being considered for a low-level waste shallow-land burial site and only minimal information about the site were available, and second, utilizing the extensive data base available for the site. The modeling results will then be compared with the empirical observations to provide insight into the level of effort needed to reasonably predict the spacial and temporal movement of radionuclides in the groundwater enviroment. 8 refs., 5 figs.,

  1. Post-irradiation examination of prototype Al-64 wt% U{sub 3}Si{sub 2} fuel rods from NRU

    SciTech Connect

    Sears, D.F.; Primeau, M.F.; Buchanan, C.; Rose, D.

    1997-08-01

    Three prototype fuel rods containing Al-64 wt% U{sub 3}Si{sub 2} (3.15 gU/cm{sup 3}) have been irradiated to their design burnup in the NRU reactor without incident. The fuel was fabricated using production-scale equipment and processes previously developed for Al-U{sub 3}Si fuel fabrication at Chalk River Laboratories, and special equipment developed for U{sub 3}Si{sub 2} powder production and handling. The rods were irradiated in NRU up to 87 at% U-235 burnup under typical driver fuel conditions; i.e., nominal coolant inlet temperature 37{degrees}C, inlet pressure 654 kPa, mass flow 12.4 L/s, and element linear power ratings up to 73 kW/m. Post-irradiation examinations showed that the fuel elements survived the irradiation without defects. Fuel core diametral increases and volumetric swelling were significantly lower than that of Al-61 wt% U{sub 3}Si fuel irradiated under similar conditions. This irradiation demonstrated that the fabrication techniques are adequate for full-scale fuel manufacture, and qualified the fuel for use in AECL`s research reactors.

  2. Waste Management Improvement Initiatives at Atomic Energy of Canada Limited - 13091

    SciTech Connect

    Chan, Nicholas; Adams, Lynne; Wong, Pierre

    2013-07-01

    Atomic Energy of Canada Limited's (AECL) Chalk River Laboratories (CRL) has been in operation for over 60 years. Radioactive, mixed, hazardous and non-hazardous wastes have been and continue to be generated at CRL as a result of research and development, radioisotope production, reactor operation and facility decommissioning activities. AECL has implemented several improvement initiatives at CRL to simplify the interface between waste generators and waste receivers: - Introduction of trained Waste Officers representing their facilities or activities at CRL; - Establishment of a Waste Management Customer Support Service as a Single-Point of Contact to provide guidance to waste generators for all waste management processes; and - Implementation of a streamlined approach for waste identification with emphasis on early identification of waste types and potential disposition paths. As a result of implementing these improvement initiatives, improvements in waste management and waste transfer efficiencies have been realized at CRL. These included: 1) waste generators contacting the Customer Support Service for information or guidance instead of various waste receivers; 2) more clear and consistent guidance provided to waste generators for waste management through the Customer Support Service; 3) more consistent and correct waste information provided to waste receivers through Waste Officers, resulting in reduced time and resources required for waste management (i.e., overall cost); 4) improved waste minimization and segregation approaches, as identified by in-house Waste Officers; and 5) enhanced communication between waste generators and waste management groups. (authors)

  3. Multi-purpose hydrogen isotopes separation plant design

    SciTech Connect

    Boniface, H.A.; Gnanapragasam, N.V.; Ryland, D.K.; Suppiah, S.; Castillo, I.

    2015-03-15

    There is a potential interest at AECL's Chalk River Laboratories to remove tritium from moderately tritiated light water and to reclaim tritiated, downgraded heavy water. With only a few limitations, a single CECE (Combined Electrolysis and Catalytic Exchange) process configuration can be designed to remove tritium from heavy water or light water and upgrade heavy water. Such a design would have some restrictions on the nature of the feed-stock and tritium product, but could produce essentially tritium-free light or heavy water that is chemically pure. The extracted tritium is produced as a small quantity of tritiated heavy water. The overall plant capacity is fixed by the total amount of electrolysis and volume of catalyst. In this proposal, with 60 kA of electrolysis a throughput of 15 kg*h{sup -1} light water for detritiation, about 4 kg*h{sup -1} of heavy water for detritiation and about 27 kg*h{sup -1} of 98% heavy water for upgrading can be processed. Such a plant requires about 1,000 liters of AECL isotope exchange catalyst. The general design features and details of this multi-purpose CECE process are described in this paper, based on some practical choices of design criteria. In addition, we outline the small differences that must be accommodated and some compromises that must be made to make the plant capable of such flexible operation. (authors)

  4. The water quality of the River Thame in the Thames Basin of south/south-eastern England.

    PubMed

    Neal, Colin; Neal, Margaret; Hill, Linda; Wickham, Heather

    2006-05-01

    The water quality of the River Thame, a tributary of the River Thames in the Thames basin, is described in relation to point and diffuse contaminant inputs and runoff from permeable and impermeable bedrock geology with their own characteristic water quality. The data is examined to see if the market town of Aylesbury in the upper part of the catchment influences water quality. Previous studies highlighted the influence of Aylesbury sewage treatment works (STW) on soluble reactive phosphorus (SRP) concentrations in the river before and after phosphorus (P) stripping at the STW. Variations in water quality along the river are described and the study indicates that, apart from SRP, water quality determinants seem to be relatively unaffected by Aylesbury. The Thame water quality is compared with other catchment typologies and it is very similar to that of the main stem of the Thames even though the Thames is mainly Chalk groundwater fed. Differences in water quality largely link to the amount of STW effluent within the rivers and to the endmember compositions of the groundwater and near surface water sources.

  5. Niger River

    Atmospheric Science Data Center

    2013-04-15

    ... third largest river in Africa, the Niger, forms an inland delta in central Mali. This Multi-angle Imaging SpectroRadiometer (MISR) image ... the region as it appears after the rainy season, when the delta is flooded. The image covers an area measuring about 400 kilometers x 450 ...

  6. Mississippi River

    Atmospheric Science Data Center

    2014-05-15

    ... to melt and the Wapsipinicon River was 52 centimeters above flood stage at De Witt, Iowa (between Clinton and Davenport). By mid-April ... slightly below the level reached in the record-setting flood of 1993. MISR was built and is managed by NASA's Jet Propulsion ...

  7. Extra-Mediterranean glacial refugia in a Mediterranean faunal element: the phylogeography of the chalk-hill blue Polyommatus coridon (Lepidoptera, Lycaenidae)

    PubMed Central

    Kühne, Gero; Kosuch, Joachim; Hochkirch, Axel; Schmitt, Thomas

    2017-01-01

    Most warm-adapted Central European species are thought to have survived ice ages exclusively in Mediterranean refugia. During recent years, this point of view has been questioned. Therefore, we tested the hypothesis that extra-Mediterranean refugia also played a role in warm-adapted insect species and selected the chalk-hill blue, Polyommatus coridon. We sequenced two mitochondrial loci (COI, CR) in 150 individuals from 30 populations covering nearly the complete range. Minimum spanning networks and other statistical analyses concordantly revealed four genetic lineages with strong phylogeographic signal: a western group in Italy, France and western/central Germany, an eastern lineage in the Balkan Peninsula, the Carpathian Basin and eastern Central Europe, an Alpine group with populations in the Alps and southern Germany and a Pyrenean group. Our results are generally consistent with previous analyses for P. coridon based on allozymes and DNA sequences, but provide additional insights. We propose that these four lineages have evolved during allopatry in different glacial refugia, two in typical Mediterranean refugia (Apennines and Balkan Peninsulas), but two in extra-Mediterranean areas south of the Alps and Pyrenees. This supports survival of warm-adapted organisms in these regions in close geographic proximity to the refugia of high mountain species.

  8. Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 2, changes in surface morphometry from terrestrial laser scanning in the summer of 2009

    USGS Publications Warehouse

    Staley, Dennis M.; Wasklewicz, Thad A.; Coe, Jeffrey A.; Kean, Jason W.; McCoy, Scott W.; Tucker, Greg E.

    2011-01-01

    High resolution topographic data that quantify changes in channel form caused by sequential debris flows in natural channels are rare at the reach scale. Terrestrial laser scanning (TLS) techniques are utilized to capture morphological changes brought about by a high-frequency of debris-flow events at Chalk Cliffs, Colorado. The purpose of this paper is to compare and contrast the topographic response of a natural channel to the documented debris-flow events. TLS survey data allowed for the generation of high-resolution (2-cm) digital terrain models (DTM) of the channel. A robust network of twelve permanent control points permitted repeat scanning sessions that provided multiple DTM to evaluate fine-scale topographic change associated with three debris-flow events. Difference surfaces from the DTM permit the interpretations of spatial variations in channel morphometry and net volume of material deposited and eroded within and between a series of channel reaches. Each channel reach experienced erosion, deposition, and both net volumetric gains and losses were measured. Analysis of potential relationships between erosion and deposition magnitudes yielded no strong correlations with measures of channel-reach morphometry, suggesting that channel reach-specific predictions of potential erosion or deposition locations or rates cannot be adequately derived from statistical analyses of pre-event channel-reach morphometry.

  9. 33 CFR 162.90 - White River, Arkansas Post Canal, Arkansas River, and Verdigris River between Mississippi River...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Arkansas River, and Verdigris River between Mississippi River, Ark., and Catoosa, Okla.; use... White River, Arkansas Post Canal, Arkansas River, and Verdigris River between Mississippi River, Ark... apply to: (1) Waterways. White River between Mississippi River and Arkansas Post Canal, Ark.;...

  10. High concentrations of trace metals in oysters from the Patuxent River, Maryland

    SciTech Connect

    Riedel, G.; Sanders, J.; Abbe, G.

    1995-12-31

    Oyster (Crassostrea virginica) populations from the Patuxent River have been analyzed for trace metals by a number of organizations over at least the past 19 years. During that period, high concentrations of Cu (200--500 {micro}g/g dry weight), Cd (3--7 {micro}g/g) and Ag (2--8 /{micro}g/g) have been found in oysters from the oyster bars furthest up river. In particular, Cd values in oysters from this region have had concentrations approaching or exceeding current FDA warning levels throughout the period. In previous studies it was suggested that a coal-burning power plant located in that region, Chalk Point Steam Electric Station, was responsible for the copper enrichment due to the corrosion of Cu/Ni alloy condenser tubes. However, a monthly survey of trace elements in the nearby oyster populations from 1986 to the present showed only a small decline in copper concentrations after the plant switched from Cu/Ni to Ti alloy condenser tubes in 1987. Other potential sources for trace metals in the region include municipal and industrial discharges, atmospheric deposition, and biocides (anti-fouling paint in particular). The very rapid rise in trace element concentrations in oysters with position up river, and the lack of such a response by another local bivalve, the hooked mussel (Ischadium recurvum), suggests that a physiological effect of low salinity stress on oysters may be in part responsible for the high concentrations of trace metals in oysters in this region.

  11. The impact of broadleaved woodland on water resources in lowland UK: II. Evaporation estimates from sensible heat flux measurements over beech woodland and grass on chalk sites in Hampshire

    NASA Astrophysics Data System (ADS)

    Roberts, J.; Rosier, P.; Smith, D. M.

    2005-12-01

    The impact on recharge to the Chalk aquifer of substitution of broadleaved woodland for pasture is a matter of concern in the UK. Hence, measurements of energy balance components were made above beech woodland and above pasture, both growing on shallow soils over chalk in Hampshire. Latent heat flux (evaporation) was calculated as the residual from these measurements of energy balances in which sensible heat flux was measured with an eddy correlation instrument that determined fast response vertical wind speeds and associated temperature changes. Assessment of wind turbulence statistics confirmed that the eddy correlation device performed satisfactorily in both wet and dry conditions. There was excellent agreement between forest transpiration measurements made by eddy correlation and stand level tree transpiration measured with sap flow devices. Over the period of the measurements, from March 1999 to late summer 2000, changes in soil water content were small and grassland evaporation and transpiration estimated from energy balance-eddy flux measurements were in excellent agreement with Penman estimates of potential evaporation. Over the 18-month measurement period, the cumulative difference between broadleaved woodland and grassland was small but evaporation from the grassland was 3% higher than that from the woodland. In the springs of 1999 and 2000, evaporation from the grassland was greater than that from the woodland. However, following leaf emergence in the woodland, the difference in cumulative evaporation diminished until the following spring.

  12. Effect of dolomite, magnesium oxide (MgO) and chalk (CaCO3) on in vitro fermentation of amorphous and crystalline cellulose and meadow hay using inoculum from sheep.

    PubMed

    Váradyová, Zora; Baran, Miroslav; Zawadzki, Wojciech; Siroka, Peter

    2003-01-01

    Some minerals can influence some biochemical parameters of rumen fermentation. The objective of this experiment was to determine the effect of different amounts (0.1, 0.25 and 0.5 g) of dolomite and to compare the effect of dolomite, magnesium oxide (MgO) and chalk (CaCO3) upon the end products of rumen fermentation in vitro. Amorphous and crystalline cellulose as well as meadow hay were used as substrates and incubated with buffered rumen fluid in sealed fermentation bottles. In dependence on the amount of dolomite and the kind of substrate an inhibitory effect of dolomite on methane production was evident. Significant differences of methane production were found between the controls, crystalline cellulose and meadow hay with 0.5 g of dolomite. An increase of total gas production was observed for cellulose with both 0.25 and 0.5 g of dolomite and also for meadow hay with 0.5 g of dolomite. It can be concluded that there was a remarkable effect of dolomite on methane production and also a slight effect of magnesium oxide and chalk as compared to the effect of dolomite on the fermentation parameters of incubated substrates.

  13. Development and Implementation of a Comprehensive Program to Deal with Canada's Nuclear Legacy Liabilities

    SciTech Connect

    Brown, Peter; Metcalfe, Douglas; Blanchette, Marcia; Dolinar, George; Halpenny, Steven; Purdy, Chris; Smith, David; Kupferschmidt, William

    2008-01-15

    The Government of Canada nuclear legacy liabilities have resulted from 60 years of nuclear research and development (R and D) carried out on behalf of Canada by the National Research Council (1944 to 1952) and Atomic Energy of Canada Limited (AECL, 1952 to present). These liabilities are largely located at AECL research sites, and consist of shutdown research buildings (including several prototype and research reactors), a wide variety of buried and stored wastes, and contaminated lands. The shutdown buildings and contaminated lands need to be safely decommissioned to meet federal regulatory requirements, and long-term solutions need to be developed and implemented for management of the wastes. More than half of the liabilities are the result of Cold War activities during the 1940's, 50's and early 60's. The remaining liabilities stem from R and D for medical isotopes and nuclear reactor technology, as well as national science programs. About 70 percent of the liabilities are located at AECL's Chalk River Laboratories (CRL) in Ontario, and a further 20 percent are located at AECL's shutdown Whiteshell Laboratories in Manitoba. The remaining 10 percent relate largely to three shutdown prototype reactors in Ontario and Quebec, which were key to the developmental stage of Canada's CANDU reactor technology. The inventory of legacy waste includes spent fuel, high-level, intermediate-level and low-level solid and liquid radioactive waste, and wastes (largely contaminated soils) from site clean-up work across Canada. Most of the wastes are in raw, unconditioned form, and limited characterization information is available for the wastes generated in past decades. In many cases unique and potentially costly solutions will be required to recover, handle and process the wastes. In conclusion: the Government of Canada has initiated a program to deal with nuclear legacy liabilities dating back to the Cold War and the birth of nuclear technologies and medicine in Canada. The 5

  14. Mystic River Watershed

    EPA Pesticide Factsheets

    Information on the efforts of the US EPA, the Commonwealth of Massachusetts, the municipalities within the Mystic River Watershed and nongovernmental organizations to improve the water quality of the Mystic River.

  15. 33 CFR 165.510 - Delaware Bay and River, Salem River, Christina River and Schuylkill River-Regulated Navigation Area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Delaware Bay and River, Salem... Limited Access Areas Fifth Coast Guard District § 165.510 Delaware Bay and River, Salem River, Christina... Regulated Navigation Area: The navigable waters of Delaware Bay and River, Salem River, Christina River,...

  16. Flowing with Rivers

    ERIC Educational Resources Information Center

    Anderson, Heather

    2004-01-01

    This article describes a lesson in which students compare how artists have depicted rivers in paintings, using different styles, compositions, subject matter, colors, and techniques. They create a watercolor landscape that includes a river. Students can learn about rivers by studying them on site, through environmental study, and through works of…

  17. Rethinking the River.

    ERIC Educational Resources Information Center

    Tenenbaum, David

    1994-01-01

    Examines the ecological impacts of the Mississippi River flood of 1993 and the rethinking of river management practices that has resulted. Provides a map of the flood area which shows the occurrence of rare wildlife found in or near the region's rivers. (LZ)

  18. Mathematics. Rivers Curriculum Guide.

    ERIC Educational Resources Information Center

    Brueggeman, Gail; Clendenin, Donna

    The Rivers Project at Southern Illinois University began in February, 1990 as a pilot program involving eight high schools along the Mississippi and lower Illinois River. The Rivers Project network has grown through the training of teachers from across the United States and Canada. With scientific literacy as the ultimate goal, students collect…

  19. Measuring River Pollution

    ERIC Educational Resources Information Center

    Ayyavoo, Gabriel

    2004-01-01

    The Don River watershed is located within Canada's most highly urbanized area--metropolitan Toronto. Many residential and commercial uses, including alterations to the river's course with bridges, have had a significant impact on the Don's fauna and flora. Pollutants have degraded the river's water quality, a situation exacerbated by the…

  20. Evaluation of phosphorus concentrations in relation to annual and seasonal physico-chemical water quality parameters in a UK chalk stream.

    PubMed

    Hanrahan, Grady; Gledhill, Martha; House, William A; Worsfold, Paul J

    2003-09-01

    The aim of this paper was to examine historical physico-chemical water quality parameters (1990-1997) in the River Frome, East Stoke (NGR SY867868), in order to show both annual and seasonal (monthly) trends. EpCO2 (defined as the partial pressure of CO2 in natural water divided by the equilibrium partial pressure of CO2) levels ranged from mean values of 6.32+/-0.41 in spring/summer to 7.86+/-1.17 in autumn/winter. A decreasing trend in mean annual EpCO2 was also observed, with a high of 9.61 in 1990 and a low of 5.22 in 1996. The variations were attributed to changes in pH, which showed an inverse relationship with river discharge (r2=0.47). Both pH and EpCO2 levels were strongly linked to biological activity with increases caused by primary productivity. Filterable reactive phosphorus (FRP) and total phosphorus (TP) concentrations correlated with river discharge. The results showed that the majority of the phosphorus load was transported during storm events, which agrees with results from an export coefficient model predicting phosphorus loading in the Frome catchment. Recent River Frome monitoring campaigns using an in situ flow-injection (FI)-based monitor were in agreement with phosphorus concentration and related physico-chemical trends observed during historical sampling and laboratory analysis.

  1. Area balance and strain in an extensional fault system: Strategies for improved oil recovery in fractured chalk, Gilbertown Field, southwestern Alabama -- Year 2. Annual report, March 1997--March 1998

    SciTech Connect

    Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Carroll, R.E.

    1998-09-01

    Gilbertown Field is the oldest oil field in Alabama and has produced oil from fractured chalk of the Cretaceous Selma Group and glauconitic sandstone of the Eutaw Formation. Nearly all of Gilbertown Field is still in primary recovery, although waterflooding has been attempted locally. The objective of this project is to analyze the geologic structure and burial history of Mesozoic and Tertiary strata in Gilbertown Field and adjacent areas in order to suggest ways in which oil recovery can be improved. Indeed, the decline of oil production to marginally economic levels in recent years has made this type of analysis timely and practical. Key technical advancements being sought include understanding the relationship of requisite strain to production in Gilbertown reservoirs, incorporation of synsedimentary growth factors into models of area balance, quantification of the relationship between requisite strain and bed curvature, determination of the timing of hydrocarbon generation, and identification of the avenues and mechanisms of fluid transport.

  2. Study on river regulation measures of dried-up rivers of Haihe River basin, China.

    PubMed

    Peng, Jing; Li, Shaoming; Qi, Lan

    2013-01-01

    In recent years, the ecological environment of plain rivers within Haihe River basin is questionable because of severe water shortages. Most of the rivers dry up regularly and it is therefore necessary to take measures to improve the river ecological environment. Meanwhile, flood control is the principal function for most of the dried-up rivers, so river regulation works for flood control also should be undertaken. In this paper, some measures of river regulation were selected applied to the Haihe River basin, taking these measures not only ensure the river security but also realize its ecological benefit. Examples of the application of selected measures for the representative rivers, Yongding River and Hutuo River, both located within the Haihe River basin, are also assessed. These measures provide practical solutions to ecological and flood control problems of dried-up rivers, are generic in nature, and could therefore be applied to other same type rivers.

  3. Evidence for methane-subsidised secondary production in a groundwater-fed lowland river.

    NASA Astrophysics Data System (ADS)

    Trimmer, M.; Grey, J.; Hildrew, A.; Jackson, M.

    2009-04-01

    We are probably familiar with the chemosynthetic ecosystems of the deep Pacific, where life in the dark is coupled to the oxidation of sulphur from ‘black smokers' rather than the sun, but few, if any, would suspect such a mode of life in the classic chalk rivers of southern England. We measured the delta13C values of dominant primary consumers and their potential food sources in a groundwater-fed lowland river. The delta13C of most consumers, such as Gammarus and Simulium, reflected that of the dominant forms of photosynthetic production, whereas the cased larvae of two caddis flies (Agapetus and Silo) were consistently 13C-depleted throughout the year. The river water was supersaturated (50-60 times atmospheric) with methane, reflecting both supersaturation in the groundwater and local production in fine sediments. We measured significant rates of methane oxidation, which generates 13C-depleted organic carbon, in the biofilms on gravel, on the caddis fly cases, and on the bottom of larger rocks. In addition, there was a marked difference in the ratio of methane oxidising potential to chlorophyll a across those substrata. This ratio was below detection in the biofilm (i.e. no methane oxidation) on the tops of rocks, greater on the bottom of rocks, and maximal for the gravels and the caddis cases. If the caddis larvae acquire most of their carbon by grazing the tops of such rocks (where they are normally found), then they must acquire their depleted delta13C values by occasionally grazing biofilm where the ratio of methane oxidation to chlorophyll was much greater, and the most likely candidate is from their own cases. Grazing methane oxidising bacteria could provide the caddis larvae with up to 30 % of their carbon, which could represent a true subsidy from an ancient groundwater source.

  4. Ice Atlas 1985 - 1986. Monongahela River, Allegheny River, Ohio River, Illinois River and Kankakee River.

    DTIC Science & Technology

    1987-11-01

    V 0 1m =1 uvydae aury1,18 Belevlle oo Sufc MAPUNTS( MArea concentration MAP NITS(in 2 x 106) (%/) Oppen water 24.97 NA Solid ice cover 0.00 NA Solid...January 28, 1986 ideo Ta-pe 14 Lock and Dam #3 Pool.- Allegheny River: 1/1 / New Kensington Bridge 19- Lock and Dam #2 Pool Surface MArea

  5. Rivers: Nature's Wondrous Waterways.

    ERIC Educational Resources Information Center

    Harrison, David L.

    Rivers play a vital role in the life of the planet. They provide water for wildlife, plant life, and people, and they help to fertilize fields where corn and other crops grow. But how were these rivers made? This children's book takes readers/students on a journey down a river from its source at the top of a mountain to its mouth where it meets…

  6. Mountain Rivers Revisited

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2011-12-01

    Published in 2000, the original Mountain Rivers was written to provide a concise summary of the scientific understanding of the distinct subset of rivers that gave the book its name. Spurred by developments in the field in the past decade, the book's author, Ellen Wohl, produced Mountain Rivers Revisited, an updated edition aimed at graduate students and professional researchers. In this interview, Eos talks to Wohl about steep channels, climate change, and opportunities for future research.

  7. Student-Designed River Study.

    ERIC Educational Resources Information Center

    Turkall, Sheila Florian

    1996-01-01

    Describes an integrated student-designed investigation in which students explore different aspects of the Chagrin River including the river ecosystem, velocity and average depth, river flooding, water quality, and economic and political factors. (JRH)

  8. OBT/HTO ratio in agricultural produce subject to routine atmospheric releases of tritium.

    PubMed

    Korolevych, V Y; Kim, S B; Davis, P A

    2014-03-01

    The mean expected value of the OBT/HTO ratio (i.e. generic ratio) is derived in this study on the joint basis of a long-term study conducted at Atomic Energy of Canada Limited (AECL)'s Chalk River Laboratories (CRL), model simulations targeted at filling gaps in a yet incomplete timeline of CRL measurements and a reference dataset comprised of numerous experiments reported in the literature. Cultivar variability and disparity in site-specific settings are covered by the reference dataset. Dynamical variability caused by meteorology has been a specific target of the long-term experimental campaign at CRL, where the former two types of variability were eliminated. The distribution of OBT/HTO ratios observed at CRL appears to be a fairly good match to the distribution of OBT/HTO ratios from the literature. This implies that dynamical variability appears important in both cases. Dynamics of atmospheric HTO at CRL is comprised of a sequence of episodes of atmospheric HTO uptake and re-emission of plant HTO. The OBT/HTO ratio appears sensitive to the proportion of the duration of these two episodes: the lesser the frequency (and duration) of plume arrivals, the higher the expected mean OBT/HTO ratio. With the plume arrival frequency defined by the typical wind rose, one would encounter a mean OBT/HTO ratio close to 2. It is important to note that this number is seen both in the reference dataset, and in the continuous timeline of HTO and OBT reconstructed from CRL observations by dynamical interpolation (modelling). Many datasets (including that of CRL) targeted at the OBT/HTO ratio are biased high compared to the suggested number. This could be explained by scarce measurements of the low OBT/HTO ratios in the short phase of uptake of atmospheric HTO by the plant.

  9. Regulation of surface water quality in a Cretaceous Chalk catchment, UK: an assessment of the relative importance of instream and wetland processes.

    PubMed

    Prior, H; Johnes, P J

    2002-01-23

    To investigate the relative importance of instream nutrient spiralling and wetland transformation processes on surface water quality, total nitrogen (TN) and total phosphorus (TP) concentrations in a 200-m reach of the River Lambourn in the south-east of England were monitored over a 2-year period. In addition, the soil pore water nutrient dynamics in a riparian ecosystem adjacent to the river were investigated. Analysis of variance indicated that TN, TP and suspended sediment concentrations recorded upstream of the wetland were statistically significantly higher (P < 0.05) than those downstream of the site. Such results suggest that the wetland was performing a nutrient retention function. Indeed, analysis of soil pore waters within the site show that up to 85% of TN and 70% of TP was removed from water flowing through the wetland during baseflow conditions, thus supporting the theory that the wetland played an important role in the regulation of surface water quality at the site. However, the small variations observed (0.034 mg TN l(-1) and 0.031 mg P l(-1)) are consistent with the theory of nutrient spiralling suggesting that both instream and wetland retention processes have a causal effect on surface water quality.

  10. One river, many stories

    EPA Science Inventory

    Interactive exhibition elements include opportunity to add stories, drawings, and place names to maps of the river; record & share your vision for the river with public television. The Duluth Art Institute will present the kick-off event for the month-long media focus around ...

  11. Umpqua River Entrance, Oregon.

    DTIC Science & Technology

    In a letter from the Portland District dated 28 March 1975, subject: ’Tidal Hydraulics Committee Services - Umpqua River Entrance, Oregon,’ the...Committee on Tidal Hydraulics was requested to assist in the evaluation of navigation problems at the entrance to the Umpqua River. As a result, the 80th

  12. Alaska Glaciers and Rivers

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image on October 7, 2007, showing the Alaska Mountains of south-central Alaska already coated with snow. Purple shadows hang in the lee of the peaks, giving the snow-clad land a crumpled appearance. White gives way to brown on the right side of the image where the mountains yield to the lower-elevation Susitna River Valley. The river itself cuts a silver, winding path through deep green forests and brown wetlands and tundra. Extending from the river valley, are smaller rivers that originated in the Alaska Mountains. The source of these rivers is evident in the image. Smooth white tongues of ice extend into the river valleys, the remnants of the glaciers that carved the valleys into the land. Most of the water flowing into the Gulf of Alaska from the Susitna River comes from these mountain glaciers. Glacier melt also feeds glacier lakes, only one of which is large enough to be visible in this image. Immediately left of the Kahiltna River, the aquamarine waters of Chelatna Lake stand out starkly against the brown and white landscape.

  13. Mississippi River. [Lesson Plan].

    ERIC Educational Resources Information Center

    Buchberg, Wendy

    Based on novels and books about the Mississippi River, this lesson plan presents activities designed to help students understand that the Mississippi River has made its mark on America's geography, commerce, and literature; and that booktalks provide a summary, explains what kind of reader the book will appeal to, and may also contain a oral…

  14. 76 FR 51887 - Safety Zone; Patuxent River, Patuxent River, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-19

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Patuxent River, Patuxent River, MD AGENCY... safety zone during the ``NAS Patuxent River Air Expo '11,'' which consists of aerial practices, performance demonstrations and air shows, to be held over certain waters of the Patuxent River adjacent...

  15. 36 CFR 7.89 - New River Gorge National River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false New River Gorge National River. 7.89 Section 7.89 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.89 New River Gorge National River....

  16. Uranium in river water

    SciTech Connect

    Palmer, M.R. ); Edmond, J.M. )

    1993-10-01

    The concentration of dissolved uranium has been determined in over 250 river waters from the Orinoco, Amazon, and Ganges basins. Uranium concentrations are largely determined by dissolution of limestones, although weathering of black shales represents an important additional source in some basins. In shield terrains the level of dissolved U is transport limited. Data from the Amazon indicate that floodplains do not represent a significant source of U in river waters. In addition, the authors have determined dissolved U levels in forty rivers from around the world and coupled these data with previous measurements to obtain an estimate for the global flux of dissolved U to the oceans. The average concentration of U in river waters is 1.3 nmol/kg, but this value is biased by very high levels observed in the Ganges-Brahmaputra and Yellow rivers. When these river systems are excluded from the budget, the global average falls to 0.78 nmol/kg. The global riverine U flux lies in the range of 3-6 [times] 10[sup 7] mol/yr. The major uncertainty that restricts the accuracy of this estimate (and that of all other dissolved riverine fluxes) is the difficulty in obtaining representative samples from rivers which show large seasonal and annual variations in runoff and dissolved load.

  17. Nile River Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The Nile River Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population. The capital city of Cairo is at the apex of the delta. Just across the river from Cairo can be seen the ancient three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

  18. Hood River Production Master Plan.

    SciTech Connect

    O'Toole, Patty

    1991-07-01

    The Northwest Power Planning Council's 1987 Columbia River Fish and Wildlife Program authorizes the development of artificial production facilities to raise chinook salmon and steelhead for enhancement in the Hood, Umatilla, Walla Walla, Grande Ronde and Imnaha rivers and elsewhere. On February 26, 1991 the Council agreed to disaggregate Hood River from the Northeast Oregon Hatchery Project, and instead, link the Hood River Master Plan (now the Hood River Production Plan) to the Pelton Ladder Project (Pelton Ladder Master Plan 1991).

  19. Mackenzie River Delta, Canada

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The Mackenzie River in the Northwest Territories, Canada, with its headstreams the Peace and Finley, is the longest river in North America at 4241 km, and drains an area of 1,805,000 square km. The large marshy delta provides habitat for migrating Snow Geese, Tundra Swans, Brant, and other waterfowl. The estuary is a calving area for Beluga whales. The Mackenzie (previously the Disappointment River) was named after Alexander Mackenzie who travelled the river while trying to reach the Pacific in 1789.

    The image was acquired on August 4, 2005, covers an area of 55.8 x 55.8 km, and is located at 68.6 degrees north latitude, 134.7 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  20. Santa Cruz River Options

    EPA Science Inventory

    This presentation summarizes qualitative research insights gained during development of a nonmarket valuation survey for changes to the Santa Cruz River in Southern Arizona. Qualitative research provides an important avenue for understanding how the public interprets valuation s...

  1. Merrimack River Watershed Communities

    EPA Pesticide Factsheets

    Listing of all communities included in each of the hydrologic unit code (HUC) 8, 10, and 12 boundaries for the Merrimack River Watershed and city locations for the EPA water quality monitoring stations.

  2. River basin management

    SciTech Connect

    Newsome, D.H.; Edwards, A.M.C.

    1984-01-01

    The quality of water is of paramount importance in the management of water resources - including marine waters. A quantitative knowledge of water quality and the factors governing it is required to formulate and implement strategies requiring an inter-disciplinary approach. The overall purpose of this conference was to bring together the latest work on water quality aspects of river basin management. These proceedings are structured on the basis of five themes: problems in international river basins; the contribution of river systems to estuarial and marine pollution; the setting of standards; monitoring; and practical water quality management including use of mathematical models. They are followed by papers from the workshop on advances in the application of mathematical modelling to water quality management, which represent some of the current thinking on the problems and concepts of river basin management.

  3. Detroit River habitat inventory

    USGS Publications Warehouse

    Manny, Bruce A.

    2003-01-01

    This inventory complements a previous survey of habitat in Ontario waters of the Detroit River (OMNR,1993). It is a starting point for balanced and sustained use of the river for natural resource conservation and economic development. The objectives of the inventory were to: (1) locate candidate sites for protection and restoration of fish and wildlife habitat in Michigan waters of the Detroit River; (2) describe the ownership and size of each site, as well as its potential for habitat protection and restoration; and (3) subjectively assess the extent to which existing habitat along the river is productive of fish and wildlife and protected from land uses that have degraded or destroyed such habitat.

  4. Colorado River Delta

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Colorado River ends its 2330 km journey in the Gulf of Mexico in Baja California. The heavy use of the river as an irrigation source for the Imperial Valley has dessicated the lower course of the river in Mexico such that it no longer consistently reaches the sea. Prior to the mid 20th century, the Colorado River Delta provided a rich estuarine marshland that is now essentially desiccated, but nonetheless is an important ecological resource.

    The image was acquired May 29, 2006, covers an area of 44.3 x 57.5 km, and is located at 32.1 degrees north latitude, 115.1 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  5. New England: Hudson River

    Atmospheric Science Data Center

    2014-05-15

    ... and recreation area. The Catskills are part of the Appalachian chain. MISR was built and is managed by NASA's Jet Propulsion ... River location:  United States region:  Eastern United States Order:  13 ...

  6. The rivers of civilization

    NASA Astrophysics Data System (ADS)

    Macklin, Mark G.; Lewin, John

    2015-04-01

    The hydromorphic regimes that underpinned Old World river-based civilizations are reviewed in light of recent research. Notable Holocene climatic changes varied from region to region, whilst the dynamics of floodplain environments were equally diverse, with river channel changes significantly affecting human settlement. There were longer-term trends in Holocene hydroclimate and multi-centennial length 'flood-rich' and 'flood-poor' episodes. These impacted on five identified flooding and settlement scenarios: (i) alluvial fans and aprons; (ii) laterally mobile rivers; (iii) rivers with well-developed levees and flood basins; (iv) river systems characterised by avulsions and floodouts; and (v) large river-fed wetlands. This gave a range of changes that were either more or less regular or incremental from year-to-year (and thus potentially manageable) or catastrophic. The latter might be sudden during a flood event or a few seasons (acute), or over longer periods extending over many decades or even centuries (chronic). The geomorphic and environmental impacts of these events on riparian societies were very often irreversible. Contrasts are made between allogenic and autogenic mechanism for imposing environmental stress on riverine communities and a distinction is made between channel avulsion and contraction responses. Floods, droughts and river channel changes can precondition as well as trigger environmental crises and societal collapse. The Nile system currently offers the best set of independently dated Holocene fluvial and archaeological records, and the contrasted effects of changing hydromorphological regimes on floodwater farming are examined. The persistence of civilizations depended essentially on the societies that maintained them, but they were also understandably resilient in some environments (Pharaonic Egypt in the Egyptian Nile), appear to have had more limited windows of opportunity in others (the Kerma Kingdom in the Nubian Nile), or required

  7. Synthetic River Valleys

    NASA Astrophysics Data System (ADS)

    Brown, R.; Pasternack, G. B.

    2011-12-01

    The description of fluvial form has evolved from anecdotal descriptions to artistic renderings to 2D plots of cross section or longitudinal profiles and more recently 3D digital models. Synthetic river valleys, artificial 3D topographic models of river topography, have a plethora of potential applications in fluvial geomorphology, and the earth sciences in general, as well as in computer science and ecology. Synthetic river channels have existed implicitly since approximately the 1970s and can be simulated from a variety of approaches spanning the artistic and numerical. An objective method of synthesizing 3D stream topography based on reach scale attributes would be valuable for sizing 3D flumes in the physical and numerical realms, as initial input topography for morphodynamic models, stream restoration design, historical reconstruction, and mechanistic testing of interactions of channel geometric elements. Quite simply - simulation of synthetic channel geometry of prescribed conditions can allow systematic evaluation of the dominant relationships between river flow and geometry. A new model, the control curve method, is presented that uses hierarchically scaled parametric curves in over-lapping 2D planes to create synthetic river valleys. The approach is able to simulate 3D stream geometry from paired 2D descriptions and can allow experimental insight into form-process relationships in addition to visualizing past measurements of channel form that are limited to two dimension descriptions. Results are presented that illustrate the models ability to simulate fluvial topography representative of real world rivers as well as how channel geometric elements can be adjusted. The testing of synthetic river valleys would open up a wealth of knowledge as to why some 3D attributes of river channels are more prevalent than others as well as bridging the gap between the 2D descriptions that have dominated fluvial geomorphology the past century and modern, more complete, 3D

  8. Rationing a river

    SciTech Connect

    Boslough, J.

    1981-06-01

    The emerging water crisis in the southwestern U.S. is examined. The Colorado River, a major water source for this region, has been allocated and diverted for irrigation, domestic, and other applications. Tunnels and aqueducts carry the water across deserts to various cities, which could not exist without this imported resource. By 1985, water demand in this region is expected to exceed supply. The river's increasing salt content further threatens the value of this dwindling resource. (2 maps, 7 photos)

  9. Paying for healthy rivers.

    PubMed

    Pigram, J J J

    2002-01-01

    Concerted efforts are being made at state and federal levels to restore Australia's rivers and waterways to a healthy condition. Yet, there is little consensus on what constitutes a "healthy river" and even less on how to achieve this, or how far to go towards restoration. Some advocate removal of storages and weirs along rivers to revert to some natural state. Others, particularly water users, question the trade-offs involved in leaving more water in the rivers and how the costs of restoration are to be met. At present it seems that the major share of the costs is borne by irrigators, with the wider community essentially enjoying a "free-ride". This situation is justified on the basis of the impactor pays principle whereby water diversions, primarily for irrigation, are held to have contributed most to degradation of the river systems. The altemative-beneficiary pays principle--is of more relevance where demands are made on resource users to mitigate environmental impacts or bring about environmental improvements, eg. healthy rivers, where the beneficiaries are the wider public and the general community. Many resource users are voluntarily undertaking action on private land to conserve biodiversity and achieve sustainability. In these circumstances, the cost-sharing principle should apply, with governments, interest groups and the community contributing to the investment required to attain the desired resource condition objectives.

  10. Long-term channel adjustment and geomorphic feature creation by vegetation in a lowland, low energy river

    NASA Astrophysics Data System (ADS)

    Grabowski, Robert; Gurnell, Angela

    2016-04-01

    Physical habitat restoration is increasingly being used to improve the ecological status of rivers. This is particularly true for lowland streams which are perceived to lack sufficient energy to create new features or to flush out fine sediment derived from agricultural and urban sources. However, this study has found that even in low-energy, base-flow dominated chalk streams, physical habitat improvement can happen naturally without direct human intervention. Furthermore this positive change is achieved by components of the river that are often regarded as management problems: in-stream macrophytes (i.e. weed), riparian trees, woody debris, and most importantly fine sediment. This project investigated the long-term changes in channel planform for the River Frome (Dorset, UK) over the last 120 years and the role of aquatic and riparian vegetation in driving this change. Agricultural census data, historical maps, recent aerial images and field observations were analysed within a process-based, hierarchical framework for hydromorphological assessment, developed in the EU FP7 REFORM project, to investigate the source and timing of fine sediment production in the catchment, to quantify the reach-scale geomorphic response, and to identify vegetation-related bedforms that could be responsible for the adjustment. The analysis reveals that the channel has narrowed and become more sinuous in the last 50-60 years. The timing of this planform adjustment correlates with substantial changes in land use and agricultural practices (post-World War II) that are known to increase soil erosion and sediment connectivity. The field observations and recent aerial images suggest that the increased delivery of fine sediment to the channel has been translated into geomorphic adjustment and diversification though the interactions between vegetation, water flow and sediment. Emergent aquatic macrophytes are retaining fine sediment, leading to the development of submerged shelves that aggrade

  11. [Health assessment of river ecosystem in Haihe River Basin, China].

    PubMed

    Hao, Li-Xia; Sun, Ran-Hao; Chen, Li-Ding

    2014-10-01

    With the development of economy, the health of river ecosystem is severely threatened because of the increasing effects of human activities on river ecosystem. In this paper, the authors assessed the river ecosystem health in aspects of chemical integrity and biological integrity, using the criterion in water quality, nutrient, and benthic macroinvertebrates of 73 samples in Haihe River Basin. The research showed that the health condition of river ecosystem in Haihe River Basin was bad overall since the health situation of 72. 6% of the samples was "extremely bad". At the same time, the health situation in Haihe River Basin exhibited obvious regional gathering effect. We also found that the river water quality was closely related to human activities, and the eutrophication trend of water body was evident in Haihe River Basin. The biodiversity of the benthic animal was low and lack of clean species in the basin. The indicators such as ammonia nitrogen, total nitrogen and total phosphorus were the key factors that affected the river ecosystem health in Haihe River Basin, so the government should start to curb the deterioration of river ecosystem health by controlling these nutrients indicators. For river ecosystem health assessment, the multi-factors comprehensive evaluation method was superior to single-factor method.

  12. 33 CFR 207.380 - Red Lake River, Minn.; logging regulations for portion of river above Thief River Falls.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Red Lake River, Minn.; logging regulations for portion of river above Thief River Falls. 207.380 Section 207.380 Navigation and Navigable... Red Lake River, Minn.; logging regulations for portion of river above Thief River Falls. (a)...

  13. 50 CFR 226.205 - Critical habitat for Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook salmon. 226.205 Section... Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook... River salmon (except reaches above impassable natural falls, and Dworshak and Hells Canyon...

  14. The Colorado River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Moderate-resolution Imaging Spectroradiometer (MODIS) true-color image shows the passage of the Colorado River through several southwestern states. The river begins, in this image, in Utah at the far upper right, where Lake Powell is visible as dark pixels surrounded by the salmon-colored rocks of the Colorado Plateau. The Colorado flows southwest through Glen Canyon, to the Glen Canyon Dam, on the Utah-Arizona border. From there it flows south into Arizona, and then turns sharply west where the Grand Canyon of the Colorado cuts through the mountains. The Colorado flows west to the Arizona-Nevada (upper left) border, where it is dammed again, this time by the Hoover Dam. The dark-colored pixels surrounding the bend in the river are Lake Mead. The river flows south along the border of first Nevada and Arizona and then California and Arizona. The Colorado River, which begins in Rocky Mountain National Park in Colorado, empties into the Gulf of California, seen at the bottom center of this image.

  15. Sharing the rivers. Overview.

    PubMed

    Postel, S

    1996-01-01

    Globally, water use has more than tripled since 1950, and the answer to this rising demand generally has been to build more and bigger water supply projects, particularly dams and river diversions. As population and consumption levels grow, more and more rivers are being dammed, diverted, or overtapped to supply increasing volumes of water to cities, industries, and farms. Among these rivers are the Nile in northeast Africa, the Ganges in south Asia, the Amu Dar'ya and Syr Dar'ya in the Aral Sea basin, the Huang He (Yellow River) in China, and the Colorado. Subsequently, such massive change in the global aquatic environment generated deterioration, decline, and in some cases, collapse in aquatic systems. In addition, competition for water is increasing not only between the human economy and the natural environment, but also between and within countries. Water scarcity is a potential source of conflict. Forces such as the depletion of resources; population growth; and unequal distribution or access can create political conflicts. Achieving more sustainable patterns of water use, restoring and maintaining the integrity of river systems, and cooperation within and between countries will not only protect the aquatic environment, but also avert conflict.

  16. 76 FR 36447 - Safety Zone; Patuxent River, Patuxent River, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Patuxent River, Patuxent River, MD AGENCY... a temporary safety zone during the ``NAS Patuxent River Air Expo '11'', which consists of aerial practices, performance demonstrations and air shows, to be held over certain waters of the Patuxent...

  17. 33 CFR 117.734 - Navesink River (Swimming River).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Navesink River (Swimming River). 117.734 Section 117.734 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... (Swimming River). The Oceanic Bridge, mile 4.5, shall open on signal; except that, from December 1...

  18. 33 CFR 117.734 - Navesink River (Swimming River).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Navesink River (Swimming River). 117.734 Section 117.734 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... (Swimming River). The Oceanic Bridge, mile 4.5, shall open on signal; except that, from December 1...

  19. 33 CFR 117.734 - Navesink River (Swimming River).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Navesink River (Swimming River). 117.734 Section 117.734 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... (Swimming River). The Oceanic Bridge, mile 4.5, shall open on signal; except that, from December 1...

  20. 33 CFR 117.734 - Navesink River (Swimming River).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Navesink River (Swimming River). 117.734 Section 117.734 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... (Swimming River). The Oceanic Bridge, mile 4.5, shall open on signal; except that, from December 1...

  1. 33 CFR 117.734 - Navesink River (Swimming River).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Navesink River (Swimming River). 117.734 Section 117.734 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... (Swimming River). The Oceanic Bridge, mile 4.5, shall open on signal; except that, from December 1...

  2. The Nile River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of the northern portion of the Nile River was captured by MISR's nadir camera on January 30, 2001 (Terra orbit 5956). The Nile is the longest river in the world, extending for about 6700 kilometers from its headwaters in the highlands of eastern Africa. At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids of Giza. North of here the Nile branches into two distributaries, the Rosetta to the west and the Damietta to the east. Also visible in this image is the Suez Canal, a shipping waterway connecting Port Said on the Mediterranean Sea with the Gulf of Suez. The Gulf is an arm of the Red Sea, and is located on the righthand side of the picture. Image credit: NASA/GSFC/LaRC/JPL, MISR Team.

  3. Delaware River Basin

    USGS Publications Warehouse

    Fischer, Jeffrey M.

    1999-01-01

    Assessing the quality of water in every location of the Nation would not be practical. Therefore, NAWQA investigations are conducted within 59 selected areas called study units (fig. 1). These study units encompass important river and aquifer systems in the United States and represent the diverse geographic, waterresource, land-use, and water-use characteristics of the Nation. The Delaware River Basin is one of 15 study units in which work began in 1996. Water-quality sampling in the study unit will begin in 1999. This fact sheet provides a brief overview of the NAWQA program, describes the Delaware River Basin study unit, identifies the major water-quality issues in the basin, and documents the plan of study that will be followed during the study-unit investigation.

  4. Osmium in the rivers

    SciTech Connect

    Sharma, M. |; Wasserburg, G.J.

    1997-12-01

    There is a large uncertainty in our understanding of the behavior of osmium during weathering and transport into deep oceans and the osmium budget of the oceans. The problem stems chiefly from the lack of osmium data on the dissolved load in the rivers and in the estuaries. In this study, the concentration and isotopic composition of osmium have been determined in three North American rivers (the Mississippi, the Columbia, and the Connecticut) and one river draining central Europe and flowing into the Baltic Sea (the Vistula). Osmium concentration in the Mississippi and the Vistula is about 45 femto mol kg{sup -1}; it is about 14 and 15 femto mol kg{sup -1} for the Connecticut and the Columbia, respectively. The {sup 187}Os/{sup 186}Os ratios estimated for the Mississippi and the Vistula are 10.4 and 10.7, respectively. For the Connecticut and the Columbia {sup 187}Os/{sup 186}Os = 8.8 and 14.4, respectively. Of all the rivers examined, the Mississippi is by far the largest, supplying {approximately}1.6% of the total annual world river flow. Its osmium isotopic composition is identical to the upper Mississippi valley loesses indicating (1) congruent dissolution of the bedrock and (2) little or no impact of anthropogenic sources on the osmium isotopic composition of the dissolved load. The latter observation indicates that the upper limit of the anthropogenic input in the dissolved osmium load of the Mississippi outflow is about 250 g yr{sup -1}. While the osmium concentration of the Vistula is high the isotopic composition does not appear to have been affected by substantial pollution. The river data can be used to put limits on the mean residence time of osmium in the oceans ({bar {tau}}{sub Os}) and on the osmium budget of the oceans. 17 refs., 1 fig., 1 tab.

  5. Regional river sulfur runoff

    SciTech Connect

    Husar, R.B.; Husar, J.D.

    1985-01-20

    The water and sulfur runoff data for 54 large river basins were assembled, covering 65% of the nondesert land area of the world. The sulfur concentration ranges from 0.5 mg S/L for the West African rivers Niger and Volta to 100 mg S/L in the Colorado River; the world average is 3.2 mg S/L. The concentrations in central and eastern Europe as well as central and eastern North America exceed 8 mg S/L. The sulfur runoff density is also highest in the river basins over these industrialized regions, exceeding 2 g S/m/sup 2//yr. However, high sulfur runoff density in excess of 3 g S/m/sup 2//yr is also measured over the Pacific islands New Zealand and New Guinea and the archipelagos of Indonesia and the Philippines. The natural background sulfur runoff was estimated by assuming that South America, Africa, Australia, and the Pacific Islands are unperturbed by man and that the average river sulfur concentration is in the range 1--3 mg S/L. Taking these background concentration values, the man-induced sulfur runoff for Europe ranges between 2 and 8 times the natural flow, and over North America, man's contribution ranges between 1 and 5 times the natural runoff. The global sulfur flow from nondesert land to the oceans and the Caspian Sea is estimated as 131 Tg S/yr, of which 46--85 Tg S/yr is attributed to natural causes. The regional river sulfur runoff pattern discussed in this paper does not have enough spatial resolution to be directly applicable to studies of the environmental effects of man-induced sulfur flows. However, it points to the continental-size regions where those perturbations are most evident and to the magnitude of the perturbations as expressed in units of the natural flows.

  6. Regional river sulfur runoff

    NASA Astrophysics Data System (ADS)

    Husar, Rudolf B.; Husar, Janja Djukic

    1985-01-01

    The water and sulfur runoff data for 54 large river basins were assembled, covering 65% of the nondesert land area of the world. The sulfur concentration ranges from 0.5 mg S/L for the West African rivers Niger and Volta to 100 mg S/L in the Colorado River; the world average is 3.2 mg S/L. The concentrations in central and eastern Europe as well as central and eastern North America exceed 8 mg S/L. The sulfur runoff density is also highest in the river basins over these industrialized regions, exceeding 2 g S/m2/yr. However, high sulfur runoff density in excess of 3 g S/m2/yr is also measured over the Pacific islands New Zealand and New Guinea and the archipelagos of Indonesia and the Philippines. The natural background sulfur runoff was estimated by assuming that South America, Africa, Australia, and the Pacific Islands are unperturbed by man and that the average river sulfur concentration is in the range 1-3 mg S/L. Taking these background concentration values, the man-induced sulfur runoff for Europe ranges between 2 and 8 times the natural flow, and over North America, man's contribution ranges between 1 and 5 times the natural runoff. The global sulfur flow from nondesert land to the oceans and the Caspian Sea is estimated as 131 Tg S/yr, of which 46-85 Tg S/yr is attributed to natural causes. The regional river sulfur runoff pattern discussed in this paper does not have enough spatial resolution to be directly applicable to studies of the environmental effects of man-induced sulfur flows. However, it points to the continental-size regions where those perturbations are most evident and to the magnitude of the perturbations as expressed in units of the natural flows.

  7. Charles River Crossing

    DTIC Science & Technology

    2012-04-06

    piled shaft or precast concrete caissons can be used to construct the foundation. The pylons are then constructed in-situ using the slip form system...Bridge and River S treet Bridge (Figure 4) are e arth-filled, r einforced concrete arch bridges that cross over the Charles River, which flows between... concrete piers and spread footings set i nto gr anular s oils a nd c lay found unde rneath t he r iver be d s ettlement. It c arries bot h vehicular

  8. Interlaboratory Comparison of Organically Bound Tritium Measurements in Environmental Samples

    SciTech Connect

    Workman, W.J.G.; Kim, S.B.; Kotzer, T.G.

    2005-07-15

    The measurement of organically bound tritium in environmental samples is essential for assessing the impact of tritium releases in terms of doses to the general public and a growing number of laboratories are now required to make them. Interlaboratory comparisons provide one way for laboratories to practice and check their analytical methods and procedures. At AECL's Chalk River Laboratories, two organic matrices with tritium concentrations less than 1.5 kBq/g were developed and distributed to seven laboratories in Canada, Europe and Russia for measurement. Some participants experienced difficulties in analysing the samples, especially with the lower concentrations, where results varied by more than an order of magnitude. Laboratories incorporating procedures such as rinsing to remove tritium from exchangeable sites, using standardized combustion methods and purifying the combustion water obtained more reliable, consistent results. The preparation of the standard reference material must be carefully executed in order to produce a homogeneous sample of uniform size. The tritium measurement community would benefit if standard reference materials in the environmental concentration range were available.

  9. Qualification of Programmable Electronic System (PES) equipment based on international nuclear I and C standards

    SciTech Connect

    De Grosbois, J.; Hepburn, G. A.; Olmstead, R.; Goble, W.; Kumar, V.

    2006-07-01

    Nuclear power plants (NPPs) are increasingly faced with the challenge of qualifying procured equipment, sub-components, and systems that contain digital programmed electronics for use in safety-related applications. Referred to as a 'programmable electronic system' (PES), such equipment typically contains both complex logic that is vulnerable to systematic design faults, and low voltage electronics hardware that is subject to random faults. Procured PES products or components are often only commercial grade, yet can offer reliable cost effective alternatives to custom-designed or nuclear qualified equipment, provided they can be shown to meet the quality assurance, functional safety, environmental, and reliability requirements of a particular application. The process of confirming this is referred to as application-specific product qualification (ASPQ) and can be challenging and costly. This paper provides an overview of an approach that has been developed at Atomic Energy Canada Limited (AECL) and successfully applied to PES equipment intended for use in domestic Candu R 6 nuclear power plants and special purpose reactors at Chalk River Laboratories. The approach has evolved over the past decade and has recently been adapted to be consistent with, and take advantage of new standards that are applicable to nuclear safety-related I and C systems. Also discussed are how recognized third-party safety-certifications of PES equipment to International Electrotechnical Commission (IEC) standards, and the assessment methods employed, may be used to reduce ASPQ effort. (authors)

  10. 3. ENVIRONMENT, FROM SOUTH, SHOWING RIVER ROAD RIDGE CARRYING CASSELMAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. ENVIRONMENT, FROM SOUTH, SHOWING RIVER ROAD RIDGE CARRYING CASSELMAN RIVER ROAD OVER CASSELMAN RIVER - River Road Bridge, Crossing Casselman River on Casselman River Road, Grantsville, Garrett County, MD

  11. Discover the Nile River

    ERIC Educational Resources Information Center

    Project WET Foundation, 2009

    2009-01-01

    Bordering on the Fantastic. As the longest river on earth, the Nile passes through 10 countries. Presented through a wide range of activities and a winning array of games, it's also unsurpassed at taking young minds into exploring the world of water, as well as natural and man made wonders.

  12. River on Trial

    ERIC Educational Resources Information Center

    Carney, Thomas R.

    1972-01-01

    Presents controversy over damming of Wyoming's Upper Green River to supply water to the arid basins of eastern Wyoming. Possibilities of wildlife destruction, flooding of valley lands, and opposition to the construction of the Kendall Dam itself are enumerated together with legislative action to date. (BL)

  13. Savannah River Site Robotics

    SciTech Connect

    2010-01-01

    Meet Sandmantis and Frankie, two advanced robotic devices that are key to cleanup at Savannah River Site. Sandmantis cleans hard, residual waste off huge underground storage tanks. Frankie is equipped with unique satellite capabilities and sensing abilties that can determine what chemicals still reside in the tanks in a cost effective manner.

  14. Savannah River Site Robotics

    ScienceCinema

    None

    2016-07-12

    Meet Sandmantis and Frankie, two advanced robotic devices that are key to cleanup at Savannah River Site. Sandmantis cleans hard, residual waste off huge underground storage tanks. Frankie is equipped with unique satellite capabilities and sensing abilties that can determine what chemicals still reside in the tanks in a cost effective manner.

  15. The River Rock School.

    ERIC Educational Resources Information Center

    Gereaux, Teresa Thomas

    1999-01-01

    In the early 1920s, the small Appalachian community of Damascus, Virginia, used private subscriptions and volunteer labor to build a 15-classroom school made of rocks from a nearby river and chestnut wood from nearby forests. The school building's history, uses for various community activities, and current condition are described. (SV)

  16. Amu Darya River

    Atmospheric Science Data Center

    2013-04-16

    ... are losing arable land to soil salinization as a result of rising groundwater levels that accompany crop irrigation. As a consequence ... the Amu Darya and Syr Darya rivers, water volume in the Aral Sea has dropped by more than 80% since 1960. Increases in water input near the ...

  17. River Pollution: Part I.

    ERIC Educational Resources Information Center

    Openshaw, Peter

    1983-01-01

    Describes a unit on river pollution and analytical methods to use in assessing temperature, pH, flow, calcium, chloride, dissolved oxygen, biochemical oxygen demand, dissolved nitrogen, detergents, heavy metals, sewage pollution, conductivity, and sediment cores. Suggests tests to be carried out and discusses significance of results. (JM)

  18. Colwater fish in rivers

    EPA Science Inventory

    A standard sampling protocol to assess the fish assemblages and abundances in large, coldwater rivers is most accurate and precise if consistent gears and levels of effort are used at each site. This requires thorough crew training, quality control audits, and replicate sampling...

  19. Nissitissit River Investigation.

    ERIC Educational Resources Information Center

    Sweatman, Jon

    Prepared for the student participant, this manual guides a day's exploration of the Nissitissit River. The unit, one of several developed in conjunction with Project Exploration, has the broad goals of promoting--through experiential learning in a variety of environments outside the classroom--the student's self-confidence and ability to work…

  20. The Nation's Rivers

    ERIC Educational Resources Information Center

    Wolman, M. Gordon

    1971-01-01

    Illustrates difficulties in measuring long term changes in water temperature and content of dissolved oxygen, inorganic ions, radiation, pesticides, and trash and debris by reference to selected U. S. river systems. Concludes that observations to detect polluters may not provide data for assessing trends and trend reversals. (AL)

  1. Ecological River Basin Management.

    ERIC Educational Resources Information Center

    Smith, Anthony Wayne

    Addressing the Seventh American Water Resources Conference, Washington, D. C., October, 1971, Anthony Wayne Smith, President, National Parks and Conservation Association, presents an expose on how rivers should be managed by methods which restores and preserve the natural life balances of the localities and regions through which they flow. The…

  2. Variation of dissolved organic carbon transported by two Chinese rivers: The Changjiang River and Yellow River.

    PubMed

    Liu, Dong; Pan, Delu; Bai, Yan; He, Xianqiang; Wang, Difeng; Zhang, Lin

    2015-11-15

    Real-time monitoring of riverine dissolved organic carbon (DOC) and the associated controlling factors is essential to coastal ocean management. This study was the first to simulate the monthly DOC concentrations at the Datong Hydrometric Station for the Changjiang River and at the Lijin Hydrometric Station for the Yellow River from 2000 to 2013 using a multilayer back-propagation neural network (MBPNN), along with basin remote-sensing products and river in situ data. The average absolute error between the modeled values and in situ values was 9.98% for the Changjiang River and 10.84% for the Yellow River. As an effect of water dilution, the variations of DOC concentrations in the two rivers were significantly negatively affected by discharge, with lower values reported during the wet season. Moreover, vegetation growth status and agricultural activities, represented by the gross primary product (GPP) and cropland area percent (CropPer) in the river basin, respectively, also significantly affected the DOC concentration in the Changjiang River, but not the Yellow River. The monthly riverine DOC flux was calculated using modeled DOC concentrations. In particular, the riverine DOC fluxes were affected by discharge, with 71.06% being reported for the Changjiang River and 90.71% for the Yellow River. Over the past decade, both DOC concentration and flux in the two rivers have not shown significant changes.

  3. Atmospheric rivers in Antarctica?

    NASA Astrophysics Data System (ADS)

    Tsukernik, M.; Lynch, A. H.

    2013-12-01

    Changes and variability in the surface mass balance signify one of the most puzzling questions of the present and future changes in Antarctica. In particular, understanding accumulation in the Eastern part of Antarctic continent presents a great challenge due to sparse and erratic observational network. Several previous publications reported an anomalously high precipitation in May 2009 in Dronning Maud Land, East Antarctica. This anomaly, supported by weather station data from the Princess Elisabeth station, 71°057' S, 23°021' E, 1392m asl, 173 km inland, also corresponded to anomalously high meridional moisture transport across the Southern Ocean inland. Using data from the ERA-Interim reanalysis project and a modified definition for the polar regions, May 2009 event has been classified as an atmospheric river event. Atmospheric river events, traditionally defined in the midlatitudes, are particularly strong and narrow corridors of moisture in middle atmosphere that can result in intense precipitation events once they reach the coast. May 2009 event was the first atmospheric river identified as far south as the Antarctic continent. In this study we perform a detailed analysis of the May 2009 atmospheric river event utilizing data from ERA -Interim and Weather Research and Forecasting (WRF) model simulations. We assess the role of the large-scale atmospheric circulation, particularly the role of the Zonal Wave 3 anomaly. We also investigate the synoptic-scale development of a storm that led to anomalous precipitation event in East Antarctica. We assess the role of upper and lower level forcing with the help of the quasi-geostrophic omega equation. We believe that such in-depth analysis of the dynamics of an atmospheric river event is crucial for better understanding present and future accumulation in the East Antarctica.

  4. Dynamic reorganization of river basins.

    PubMed

    Willett, Sean D; McCoy, Scott W; Perron, J Taylor; Goren, Liran; Chen, Chia-Yu

    2014-03-07

    River networks evolve as migrating drainage divides reshape river basins and change network topology by capture of river channels. We demonstrate that a characteristic metric of river network geometry gauges the horizontal motion of drainage divides. Assessing this metric throughout a landscape maps the dynamic states of entire river networks, revealing diverse conditions: Drainage divides in the Loess Plateau of China appear stationary; the young topography of Taiwan has migrating divides driving adjustment of major basins; and rivers draining the ancient landscape of the southeastern United States are reorganizing in response to escarpment retreat and coastal advance. The ability to measure the dynamic reorganization of river basins presents opportunities to examine landscape-scale interactions among tectonics, erosion, and ecology.

  5. Organic Compounds in Truckee River Water Used for Public Supply near Reno, Nevada, 2002-05

    USGS Publications Warehouse

    Thomas, Karen A.

    2009-01-01

    Organic compounds studied in this U.S. Geological Survey (USGS) assessment generally are man-made, including, in part, pesticides, solvents, gasoline hydrocarbons, personal care and domestic-use products, and refrigerants and propellants. Of 258 compounds measured, 28 were detected in at least 1 source water sample collected approximately monthly during 2002-05 at the intake of the Chalk Bluff Treatment Plant, on the Truckee River upstream of Reno, Nevada. The diversity of compounds detected indicate various sources and uses (including wastewater discharge, industrial, agricultural, domestic, and others) and different pathways (including point sources from treated wastewater outfalls upstream of the sampling location, overland runoff, and groundwater discharge) to drinking-water supply intakes. Three compounds were detected in more than 20 percent of the source-water intake samples at low concentrations (less than 0.1 microgram per liter), including caffeine, p-cresol (a wood preservative), and toluene (a gasoline hydrocarbon). Sixteen of the 28 compounds detected in source water also were detected in finished water (after treatment, but prior to distribution; 2004-05). Additionally, two disinfection by-products not detected in source water, bromodichloromethane and dibromochloromethane, were detected in all finished water samples. Two detected compounds, cholesterol and 3-beta-coprostanol, are among five naturally occurring biochemicals analyzed in this study. Concentrations for all detected compounds in source and finished water generally were less than 0.1 microgram per liter and always less than human-health benchmarks, which are available for about one-half of the compounds. Seven compounds (toluene, chloroform, bromodichloromethane, dibromodichloromethane, bisphenol A, cholesterol, and 3-beta-coprostanol) were measured at concentrations greater than 0.1 microgram per liter. On the basis of this screening-level assessment, adverse effects to human health are

  6. River-Corridor Habitat Dynamics, Lower Missouri River

    USGS Publications Warehouse

    Jacobson, Robert B.

    2010-01-01

    Intensive management of the Missouri River for navigation, flood control, and power generation has resulted in substantial physical changes to the river corridor. Historically, the Missouri River was characterized by a shifting, multithread channel and abundant unvegetated sandbars. The shifting channel provided a wide variety of hydraulic environments and large areas of connected and unconnected off-channel water bodies. Beginning in the early 1800s and continuing to the present, the channel of the Lower Missouri River (downstream from Sioux City, Iowa) has been trained into a fast, deep, single-thread channel to stabilize banks and maintain commercial navigation. Wing dikes now concentrate the flow, and revetments and levees keep the channel in place and disconnect it from the flood plain. In addition, reservoir regulation of the Missouri River upstream of Yankton, South Dakota, has substantially changed the annual hydrograph, sediment loads, temperature regime, and nutrient budgets. While changes to the Missouri River have resulted in broad social and economic benefits, they have also been associated with loss of river-corridor habitats and diminished populations of native fish and wildlife species. Today, Missouri River stakeholders are seeking ways to restore some natural ecosystem benefits of the Lower Missouri River without compromising traditional economic uses of the river and flood plain.

  7. Missouri River, Gavins Point Dam - Lewis and Clark Lake, Nebraska and South Dakota, Embankment Criteria and Performance Report.

    DTIC Science & Technology

    1982-05-01

    powerhouse substructure. Embankment materials included chalk and shale excavated from the structure area, over- burden soils from the diversion...the compacted chalk section. The specimens, therefore, were not uniform and were classified as CH, ML, and CL soil types with dry densiti[cs of about 95...casing. The lower 5 feet of pipe is uncased and is embedded in concrete. The space between the pipe and the casing is filled with vermiculite . Markers

  8. 77 FR 30589 - SteelRiver Infrastructure Partners LP, SteelRiver Infrastructure Associates LLC, SteelRiver...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-23

    ... Surface Transportation Board SteelRiver Infrastructure Partners LP, SteelRiver Infrastructure Associates LLC, SteelRiver Infrastructure Fund North America LP, and Patriot Funding LLC--Control Exemption--Patriot Rail Corp., et al. SteelRiver Infrastructure Partners LP (SRIP LP), SteelRiver...

  9. River networks as biodiversity hotlines.

    PubMed

    Décamps, Henri

    2011-05-01

    For several years, measures to insure healthy river functions and to protect biodiversity have focused on management at the scale of drainage basins. Indeed, rivers bear witness to the health of their drainage basins, which justifies integrated basin management. However, this vision should not mask two other aspects of the protection of aquatic and riparian biodiversity as well as services provided by rivers. First, although largely depending on the ecological properties of the surrounding terrestrial environment, rivers are ecological systems by themselves, characterized by their linearity: they are organized in connected networks, complex and ever changing, open to the sea. Second, the structure and functions of river networks respond to manipulations of their hydrology, and are particularly vulnerable to climatic variations. Whatever the scale considered, river networks represent "hotlines" for sharing water between ecological and societal systems, as well as for preserving both systems in the face of global change. River hotlines are characterized by spatial as well as temporal legacies: every human impact to a river network may be transmitted far downstream from its point of origin, and may produce effects only after a more or less prolonged latency period. Here, I review some of the current issues of river ecology in light of the linear character of river networks.

  10. Hood River Passive House

    SciTech Connect

    Hales, D.

    2013-03-01

    The Hood River Passive Project was developed by Root Design Build of Hood River Oregon using the Passive House Planning Package (PHPP) to meet all of the requirements for certification under the European Passive House standards. The Passive House design approach has been gaining momentum among residential designers for custom homes and BEopt modeling indicates that these designs may actually exceed the goal of the U.S. Department of Energy's (DOE) Building America program to reduce home energy use by 30%-50% (compared to 2009 energy codes for new homes). This report documents the short term test results of the Shift House and compares the results of PHPP and BEopt modeling of the project.

  11. Ancient River revealed

    NASA Astrophysics Data System (ADS)

    Recent flights of the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) mission aboard the space shuttle Endeavour discovered a previously unknown branch of an ancient river. The images, released at AGU's Spring Meeting, show the river channel buried under thousands of years worth of windblown sand in a region of North Africa's Sahara Desert near the Kufra Oasis in southeast Libya, centered at 23.3°N latitude, 22.9°E longitude. The image from the flight last October reveals a system of old, now inactive stream valleys, called “paleodrainage systems,” which carried running water northward across the Sahara during periods of wetter climate.

  12. River Mileages and Drainage Areas for Illinois Streams. Volume 2. Illinois River Basin.

    DTIC Science & Technology

    1979-12-01

    FOREST 50.2 MADISON STREET RIVER FOREST 50.5 IL PT 56 RIVER FOREST 51.0 C & NW RR RIVER FOREST 51.1 LAKE STREET RIVER FOREST 51.6 CHICAGO AVENUE RIVER ... FOREST 51.9 SILVER CREEK R RIVER FOREST 53.9 DAM S35v40NoRI2E RIVER FOREST 54.2 NORTH PUEBLO AVENUE RIVER FOREST 55.1 GRAND AVENUE RIVER FOREST 55.1...USGS GAGE 05530600 AT RIVER GROVE 451 415546 O75040 RIVER

  13. Red River of the North, Reconnaissance Report: Wild Rice River.

    DTIC Science & Technology

    1980-12-01

    Stations Along the Wild Rice River, October, 1977 to September, 1977 ... 30 7 Groundwater Quality of Eight Communities Within the Wild Rice River Subbasin...impair fish propagation (Upper Mississippi River Basin Commission, 1977; North Dakota Statewide 208 Water Quality Management Plan, 1978). The groundwater ...given to this reach not because of its stream fisheries, which only provide moderate amounts of northern pike, yellow perch , crappie, and several

  14. Chesapeake Bay, Potomac River

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The nation's capital lies astride the Potomac River (38.5N, 77.5W) at the head of the Potomac Estuary. Baltimore, MD, also in the scene, is connected to Washington by the Baltimore-Washington Parkway. The suburbs of both cities tend to cluster around the Washington and Baltimore Beltways. Most of the countryside in the eastern two-thirds of this scene is either heavily forested or is in farming, dairy operations or poultry production.

  15. Onilahy River, Madagascar

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Near the southern tip of Madagascar, the Onilahy River (23.5S, 44E) drains a near barren landscape, the result of rapid deforestation for quick profits from the lumber industry with no regard to the environmental impact. At the turn of the century, the island was a lush tropical paradise with about 90 percent of the surface forested. Now, at the close of the century, only about 10 percent of the forests remain in inaccessible rugged terrain.

  16. Flooding on Elbe River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Heavy rains in Central Europe over the past few weeks have led to some of the worst flooding the region has witnessed in more than a century. The floods have killed more than 100 people in Germany, Russia, Austria, Hungary, and the Czech Republic and have led to as much as $20 billion in damage. This false-color image of the Elbe River and its tributaries was taken on August 20, 2002, by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. The floodwaters that inundated Dresden, Germany, earlier this week have moved north. As can be seen, the river resembles a fairly large lake in the center of the image just south of the town of Wittenberg. Flooding was also bad further downriver in the towns of Maqgdeburge and Hitzacker. Roughly 20,000 people were evacuated from their homes in northern Germany. Fifty thousand troops, border police, and technical assistance workers were called in to combat the floods along with 100,000 volunteers. The floodwaters are not expected to badly affect Hamburg, which sits on the mouth of the river on the North Sea. Credit:Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  17. 33 CFR 125.06 - Western rivers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... VESSELS § 125.06 Western rivers. The term western rivers as used in the regulations in this subchapter shall include only the Red River of the North, the Mississippi River and its tributaries above the Huey... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Western rivers. 125.06...

  18. 33 CFR 125.06 - Western rivers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... VESSELS § 125.06 Western rivers. The term western rivers as used in the regulations in this subchapter shall include only the Red River of the North, the Mississippi River and its tributaries above the Huey... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Western rivers. 125.06...

  19. 33 CFR 125.06 - Western rivers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... VESSELS § 125.06 Western rivers. The term western rivers as used in the regulations in this subchapter shall include only the Red River of the North, the Mississippi River and its tributaries above the Huey... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Western rivers. 125.06...

  20. 33 CFR 125.06 - Western rivers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... VESSELS § 125.06 Western rivers. The term western rivers as used in the regulations in this subchapter shall include only the Red River of the North, the Mississippi River and its tributaries above the Huey... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Western rivers. 125.06...

  1. 33 CFR 125.06 - Western rivers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... VESSELS § 125.06 Western rivers. The term western rivers as used in the regulations in this subchapter shall include only the Red River of the North, the Mississippi River and its tributaries above the Huey... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Western rivers. 125.06...

  2. Tsunami Impacts in River Environments

    NASA Astrophysics Data System (ADS)

    Tolkova, E.; Tanaka, H.; Roh, M.

    2014-12-01

    The 2010 Chilean and the 2011 Tohoku tsunami events demonstrated the tsunami's ability to penetrate much farther along rivers than the ground inundation. At the same time, while tsunami impacts to the coastal areas have been subject to countless studies, little is known about tsunami propagation in rivers. Here we examine the field data and conduct numerical simulations to gain better understanding of the tsunami impacts in rivers.The evidence which motivated our study is comprised of water level measurements of the aforementioned tsunamis in multiple rivers in Japan, and the 2011 Tohoku and some other tsunamis in the Columbia River in the US. When the available tsunami observations in these very different rivers are brought together, they display remarkably similar patterns not observed on the open coast. Two phenomena were discovered in the field data. First, the phase of the river tide determines the tsunami penetration distance in a very specific way common to all rivers. Tsunami wave progressively disappears on receding tide, whereas high tide greatly facilitates the tsunami intrusion, as seen in the Figure. Second, a strong near-field tsunami causes substantial and prolonged water accumulation in lower river reaches. As the 2011 tsunami intruded rivers in Japan, the water level along rivers rose 1-2 m and stayed high for many hours, with the maximum rise occurring several km from the river mouth. The rise in the water level at some upstream gaging stations even exceeded the tsunami amplitude there.Using the numerical experiments, we attempt to identify the physics behind these effects. We will demonstrate that the nonlinear interactions among the flow components (tsunami, tide, and riverine flow) are an essential condition governing wave dynamics in tidal rivers. Understanding these interactions might explain some previous surprising observations of waves in river environments. Figure: Measurements of the 2010/02/27 tsunami along Naruse and Yoshida rivers

  3. Establishing river basin organisations inVietnam: Red River, Dong Nai River and Lower Mekong Delta.

    PubMed

    Taylor, P; Wright, G

    2001-01-01

    River basin management is receiving considerable attention at present. Part of the debate, now occurring worldwide, concerns the nature of the organisations that are required to manage river basins successfully, and whether special-purpose river basin organisations (RBOs) are always necessary and in what circumstance they are likely to (i) add to the management of the water resources and (ii) be successful. The development of river basin management requires a number of important elements to be developed to a point where the river basin can be managed successfully. These include the relevant laws, the public and non-government institutions, the technical capabilities of the people, the understanding and motivation of people, and the technical capacity and systems, including information. A river basin organisation (or RBO) is taken to mean a special-purpose organisation charged with some part of the management of the water resources of a particular river basin. Generally speaking, such organisations are responsible for various functions related to the supply, distribution, protection and allocation of water, and their boundaries follow the watershed of the river in question. However, the same functions can be carried out by various organisations, which are not configured on the geographical boundaries of a river basin. This paper outlines recent work on river basin organisation in Vietnam, and makes some comparisons with the situation in Australia.

  4. Rehabilitating China's largest inland river.

    PubMed

    Li, Yiqing; Chen, Yaning; Zhang, Yaoqi; Xia, Yang

    2009-06-01

    Wetlands are particularly important for conserving China's biodiversity but riparian wetlands in the Tarim River basin in western China have been reduced by 46% during the last 3 decades. The world's largest habitat for Populus euphratica, which is in the Tarim River basin, significantly shrank. To protect and restore the deteriorated ecosystems along the Tarim River and its associated wetlands, China's government initiated a multimillion dollar river restoration project to release water from upper dams to the dried-up lower reaches of the Tarim River starting in 2000. We monitored the responses of groundwater and vegetation to water recharge in the lower reaches of the river from 2000 to 2006 by establishing nine 1000-m-long transects perpendicular to the river at intervals of 20-45 km along the 320-km river course below the Daxihaizi Reservoir, the source of water conveyance, to Lake Taitema, the terminus of the Tarim River. Water recharges from the Daxihaizi Reservoir to the lower reaches of the Tarim River significantly increased groundwater levels and vegetation coverage at all monitoring sites along the river. The mean canopy size of the endangered plant species P. euphratica doubled after 6 years of water recharge. Some rare migrating birds returned to rest on the restored wetlands in summer along the lower reaches of the Tarim River. The biggest challenge facing decision makers, however, is to balance water allocation and water rights between agricultural and natural ecosystems in a sustainable way. A large number of inhabitants in the Tarim Basin depend on these limited water resources for a living. At the same time, the endangered ecosystems need to be protected. Given the ecological, socioeconomic, and sociopolitical realities in the Tarim Basin, adaptive water policies and strategies are needed for water allocation in these areas of limited water resources.

  5. Wild, scenic, and transcendental rivers

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    “A more lovely stream than this has never flowed on Earth,” 19th century American author Nathaniel Hawthorne wrote about the confluence of the Assabet and Concord Rivers, streams that meander about 40 km west of Boston, Massachusetts.Segments of these streams as well as the Assabet River became the newest additions to the U.S. National Wild and Scenic Rivers System, when President Bill Clinton signed into law the “Sudbury, Assabet, and Concord Wild and Scenic River Act” on April 9.

  6. 36 CFR 7.89 - New River Gorge National River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... valid West Virginia State hunting license or permit, or are exempt under provisions of West Virginia law... Superintendent for reasons of public safety, resource protection, or other management considerations. (2) Do West Virginia state hunting laws apply within New River Gorge National River? Yes, non-conflicting State...

  7. Methane Emission from Tropical Rivers

    NASA Astrophysics Data System (ADS)

    Sawakuchi, H. O.; Rasera, M. F. F. L.; Krusche, A. V.; Ballester, M. V. R.

    2012-04-01

    Inland water is already known as an important source of methane to atmosphere. Methane is produced in anaerobic environments usually find in lakes and floodplain bottom sediment. It is the main reason that almost all information regarding methane flux come from this environments. However, while floodplain dries during low water season reducing methanogenesis, rivers keep the capacity to emit methane throughout the year. Here we present preliminary results of CH4 flux measurements done in 6 large tropical rivers within the Amazon basin. We measured 17 areas using floating chamber during dry (low water) season, between September and November of 2011, in Amazon river mainstem, Araguaia, Xingu, Tapajós, Madeira, and Negro Rivers. Measured fluxes of all rivers ranged from 59.3 to 2974.4 mmol m-2 yr-1. Geomorphologic structure of channels is one important factor that contributes to this high heterogeneity due to development of low flow velocity depositional settings allowing formation of anoxic zones in rivers. Hydraulic and sediment barriers in the confluence of river channels promote the generation of natural dams which function as a trap for the suspension load favoring the deposition of organic rich muds. This kind of environment is very different from common river channels and has a stronger potential of methane emission. Average values of our flux measurements for this two river environments show that depositional areas can have much higher fluxes than the main channel, 1089.6 and 163.1 mmol m-2 yr-1, respectively. Hence, CH4 flux from these depositional zones is similar to some tropical floodplain lakes and reservoirs. Although the low flux from channel, the area covered by water is very large resulting in a significant contribution to the regional methane emission to the atmosphere. Moreover, mapping the area of these depositional river zones will give us a better idea of the magnitude of methane flux from tropical rivers.

  8. River Capture in Disequilibrium Landscapes

    NASA Astrophysics Data System (ADS)

    McCoy, S. W.; Perron, J.; Willett, S.; Goren, L.

    2013-12-01

    The process of river piracy or river capture has long drawn interest as a potential mechanism by which drainage basins large and small evolve towards an equilibrium state. River capture transfers both drainage area and drainage lines from one river basin to another, which can cause large, abrupt shifts in network topology, drainage divide positions, and river incision rates. Despite numerous case studies in which river capture has been proposed to have occurred, there is no general, mechanistic framework for understanding the controls on river capture, nor are there quantitative criteria for determining if capture has occurred. Here we use new metrics of landscape disequilibrium to first identify landscapes in which drainage reorganization is occurring. These metrics are based on a balance between an integral of the contributing drainage area and elevation. In an analysis of rivers in the Eastern United States we find that many rivers are in a state of disequilibrium and are experiencing recent or ongoing area exchange between basins. In these disequilibrium basins we find widespread evidence for network rearrangement via river capture at multiple scales. We then conduct numerical experiments with a 2-D landscape evolution model to explore the conditions in which area exchange among drainage basins is likely to occur as discrete capture events as opposed to continuous divide migration. These experiments indicate that: (1) capture activity increases with the degree of disequilibrium induced by persistent spatial gradients in tectonic forcing or by temporal changes in climate or tectonic forcing; (2) capture activity is strongly controlled by the initial planform drainage network geometry; and (3) capture activity scales with the fluvial incision rate constant in the river power erosion law.

  9. Taunton River basin

    USGS Publications Warehouse

    Williams, John R.; Willey, Richard E.

    1970-01-01

    This report presents in tabular form selected records of wells, test wells, and borings collected during a study of the basin from 1966 to 1968 in cooperation with the Massachusetts Water Resources Commission, and during earlier studies. This report is released in order to make available to the public and to local, state, and federal agencies basic ground-water information that may aid in planning water-resources development. Basic records contained in this report will complement an interpretative report on the Taunton River basin to be released at a later date.

  10. River Ice Data Instrumentation

    DTIC Science & Technology

    1997-06-01

    measurement of river ice velocity. USA Cold Re- gions Research and Engineering Laboratory, CRREL Report 95-21. Ford, J.S., S . Beltaos , W.J. Moody...moke the measurements. Existing end cBvelcpinginstrumeTtoticnv^ s edudedfain-situend remote sensing ccpcälities. Methods of Ironsmitting storing end...rrril häp@dicnnil rr6acB" s @dicnril WWW http/AMMA/cScdarril/ Al alhas rrcy ace repcrls lacughlheNalicnd Technicd Infarrdicn Sevice NTIS 5285 PCRT

  11. 7. SANDY RIVER BRIDGE AT TROUTDALE, PERSPECTIVE LOOKING EAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. SANDY RIVER BRIDGE AT TROUTDALE, PERSPECTIVE LOOKING EAST. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  12. 2. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 20 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 20 DEGREES NORTH. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  13. 6. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION, LOOKING 306 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION, LOOKING 306 DEGREES NORTHWEST. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  14. 1. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 18 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 18 DEGREES NORTH. SAME PHOTO AS OR-36-1. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  15. 5. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION DETAIL, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION DETAIL, LOOKING 6 DEGREES NORTH. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  16. 3. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 184 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 184 DEGREES SOUTH. SAME PHOTO AS OR-36-2. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  17. 4. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 224 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 224 DEGREES SOUTHWEST. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  18. River meanders and vorticity theorem

    USGS Publications Warehouse

    Leopold, Luna Bergere

    1953-01-01

    The serpentine windings of rivers, which in certain reaches attain a remarkable symmetry and are then called meanders, must represent one aspect of the tendency for establishment of quasi-equilibrium in natural streams. With the increase in knowledge of the interaction of forces operating in rivers, this tendency toward equilibrium has assumed a greater significance.

  19. Flooding on Russia's Lena River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nearly every year in the late spring, ice blocks the flow of water at the mouth of the Lena River in northeastern Russia and gives rise to floods across the Siberian plains. This year's floods can be seen in this image taken on June 2, 2002, by the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard the Terra satellite. The river runs down the left side of the image, and its delta is shrouded in ice (red) at the top of the image. Normally, the river would resemble a thin black line in MODIS imagery. The river, which is Russia's longest, flows 2,641 miles (4,250 kilometers) south to north through Siberia and into the Laptev Sea. In the winter, the river becomes nearly frozen. In the spring, however, water upstream thaws earlier than water at the mouth of the river. As the southern end of the river begins to melt, blocks of ice travel downstream to the still frozen delta, pile up, and often obstruct the flow of water. Flooding doesn't always occur on the same parts of the river. The floods hit further south last year. If the flooding grows severe enough, explosive charges are typically used to break up the ice jams. In these false-color images land areas are a dull, light green or tan, and water is black. Clouds appear pink, and ice comes across as bright red. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  20. 33 CFR 165.510 - Delaware Bay and River, Salem River, Christina River and Schuylkill River-Regulated Navigation Area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Schuylkill River, in an area bounded on the south by a line drawn across the entrance to the Delaware Bay... Cape Henlopen, and bounded on the north by a line drawn across the Delaware River between Trenton, NJ... propulsion; (7) While moored within the regulated navigation area, ensure that at least two wire...

  1. Treasure Along the Parker River.

    ERIC Educational Resources Information Center

    Fitzpatrick, Ann-Marie; And Others

    Designed so that 100 to 125 heterogeneously grouped 7th and 8th grade students and a team of 5 core teachers might experience and discover the natural and historical "treasure" in the Parker River area of Massachusetts, this interdisciplinary unit centers on a hike to Parker River (6.7 miles) and visits to a cemetery, a monument, and Old…

  2. Niagara River Toxics Management Plan

    EPA Pesticide Factsheets

    This 2007 Progress Report of the Niagara River Toxics Management Plan (NRTMP) summarizes progress made by the four parties in dealing with the 18 “Priority Toxics” through reductions in point and non-point sources to the Niagara River.

  3. Coccolithophore Cell Biology: Chalking Up Progress

    NASA Astrophysics Data System (ADS)

    Taylor, Alison R.; Brownlee, Colin; Wheeler, Glen

    2017-01-01

    Coccolithophores occupy a special position within the marine phytoplankton because of their production of intricate calcite scales, or coccoliths. Coccolithophores are major contributors to global ocean calcification and long-term carbon fluxes. The intracellular production of coccoliths requires modifications to cellular ultrastructure and metabolism that are surveyed here. In addition to calcification, which appears to have evolved with a diverse range of functions, several other remarkable features that likely underpin the ecological and evolutionary success of coccolithophores have recently been uncovered. These include complex and varied life cycle strategies related to abiotic and biotic interactions as well as a range of novel metabolic pathways and nutritional strategies. Together with knowledge of coccolithophore genetic and physiological variability, these findings are beginning to shed new light on species diversity, distribution, and ecological adaptation. Further advances in genetics and functional characterization at the cellular level will likely to lead to a rapid increase in this understanding.

  4. Getting Chalk: Distant Reflections on Deaning.

    ERIC Educational Resources Information Center

    Kirk, Stuart A.

    1997-01-01

    Although the job of a professional school dean is complex and demanding and the skills it requires are varied, it is important for the dean to acknowledge the limitations of both the job and the individual in it. Only time tells whether innovations, programs, customs, and direction created and nurtured by the dean reflect true leadership by…

  5. Coccolithophore Cell Biology: Chalking Up Progress.

    PubMed

    Taylor, Alison R; Brownlee, Colin; Wheeler, Glen

    2017-01-03

    Coccolithophores occupy a special position within the marine phytoplankton because of their production of intricate calcite scales, or coccoliths. Coccolithophores are major contributors to global ocean calcification and long-term carbon fluxes. The intracellular production of coccoliths requires modifications to cellular ultrastructure and metabolism that are surveyed here. In addition to calcification, which appears to have evolved with a diverse range of functions, several other remarkable features that likely underpin the ecological and evolutionary success of coccolithophores have recently been uncovered. These include complex and varied life cycle strategies related to abiotic and biotic interactions as well as a range of novel metabolic pathways and nutritional strategies. Together with knowledge of coccolithophore genetic and physiological variability, these findings are beginning to shed new light on species diversity, distribution, and ecological adaptation. Further advances in genetics and functional characterization at the cellular level will likely to lead to a rapid increase in this understanding.

  6. Tolerating Tolerance in the Classroom. Chalk Talk.

    ERIC Educational Resources Information Center

    Journal of Law and Education, 1996

    1996-01-01

    Many parents demand the right to instruct their children at home regarding sexual issues, while educators want the right to be honest and forthright with their students. Homosexuality is a highly emotional issue, and people are divided as to whether discussions about it have a place in the classroom. Examines several court battles. (MLF)

  7. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... where the north fork of Barnes Creek intersects such line in section 34, T. 9 N., R. 8 W.; (16) Then continuing along the north fork of Barnes Creek, approximately 0.5 mile, in a generally westerly direction...

  8. Whatever Happened to "Talk and Chalk".

    ERIC Educational Resources Information Center

    Aston, Mike

    1982-01-01

    The Microelectronics Education Programme (MEP) has focused its attentions on the classroom teacher as the agent of educational change by providing computer based learning coordinators to implement teacher training programs to support all aspects of the school curriculum. Discusses computer training before MEP, with MEP involvement, and after…

  9. Geomorphology and River Dynamics of the Lower Copper River, Alaska

    USGS Publications Warehouse

    Brabets, Timothy P.; Conaway, Jeffrey S.

    2009-01-01

    Located in south-central Alaska, the Copper River drains an area of more than 24,000 square miles. The average annual flow of the river near its mouth is 63,600 cubic feet per second, but is highly variable between winter and summer. In the winter, flow averages approximately 11,700 cubic feet per second, and in the summer, due to snowmelt, rainfall, and glacial melt, flow averages approximately 113,000 cubic feet per second, an order of magnitude higher. About 15 miles upstream of its mouth, the Copper River flows past the face of Childs Glacier and enters a large, broad, delta. The Copper River Highway traverses this flood plain, and in 2008, 11 bridges were located along this section of the highway. The bridges cross several parts of the Copper River and in recent years, the changing course of the river has seriously damaged some of the bridges. Analysis of aerial photography from 1991, 1996, 2002, 2006, and 2007 indicates the eastward migration of a channel of the Copper River that has resulted in damage to the Copper River Highway near Mile 43.5. Migration of another channel in the flood plain has resulted in damage to the approach of Bridge 339. As a verification of channel change, flow measurements were made at bridges along the Copper River Highway in 2005-07. Analysis of the flow measurements indicate that the total flow of the Copper River has shifted from approximately 50 percent passing through the bridges at Mile 27, near the western edge of the flood plain, and 50 percent passing through the bridges at Mile 36-37 to approximately 5 percent passing through the bridges at Mile 27 and 95 percent through the bridges at Mile 36-37 during average flow periods. The U.S. Geological Survey's Multi-Dimensional Surface-Water Modeling System was used to simulate water-surface elevation and velocity, and to compute bed shear stress at two areas where the Copper River is affecting the Copper River Highway. After calibration, the model was used to examine the

  10. Hood River Passive House

    SciTech Connect

    Hales, David

    2014-01-01

    The Hood River Passive Project was developed by Root Design Build of Hood River Oregon using the Passive House Planning Package (PHPP) to meet all of the requirements for certification under the European Passive House standards. The Passive House design approach has been gaining momentum among residential designers for custom homes and BEopt modeling indicates that these designs may actually exceed the goal of the U.S. Department of Energy's (DOE) Building America program to "reduce home energy use by 30%-50% (compared to 2009 energy codes for new homes). This report documents the short term test results of the Shift House and compares the results of PHPP and BEopt modeling of the project. The design includes high R-Value assemblies, extremely tight construction, high performance doors and windows, solar thermal DHW, heat recovery ventilation, moveable external shutters and a high performance ductless mini-split heat pump. Cost analysis indicates that many of the measures implemented in this project did not meet the BA standard for cost neutrality. The ductless mini-split heat pump, lighting and advanced air leakage control were the most cost effective measures. The future challenge will be to value engineer the performance levels indicated here in modeling using production based practices at a significantly lower cost.

  11. Hood River Passive House

    SciTech Connect

    Hales, D.

    2014-01-01

    The Hood River Passive Project was developed by Root Design Build of Hood River Oregon using the Passive House Planning Package (PHPP) to meet all of the requirements for certification under the European Passive House standards. The Passive House design approach has been gaining momentum among residential designers for custom homes and BEopt modeling indicates that these designs may actually exceed the goal of the U.S. Department of Energy's (DOE) Building America program to reduce home energy use by 30%-50% (compared to 2009 energy codes for new homes). This report documents the short term test results of the Shift House and compares the results of PHPP and BEopt modeling of the project. The design includes high R-Value assemblies, extremely tight construction, high performance doors and windows, solar thermal DHW, heat recovery ventilation, moveable external shutters and a high performance ductless mini-split heat pump. Cost analysis indicates that many of the measures implemented in this project did not meet the BA standard for cost neutrality. The ductless mini-split heat pump, lighting and advanced air leakage control were the most cost effective measures. The future challenge will be to value engineer the performance levels indicated here in modeling using production based practices at a significantly lower cost.

  12. River network routing in all rivers of the Texas Gulf

    NASA Astrophysics Data System (ADS)

    David, C. H.; Maidment, D. R.; Hong, S.; Niu, G.; Yang, Z.

    2009-12-01

    The mapped rivers and streams of the contiguous United States are available in a high resolution geographic information system (GIS) dataset called NHDPlus. This hydrographic dataset has about 3 million river and water body reaches along with information on how they are connected into networks. A river network model called RAPID is developed for the NHDPlus river network and applied to the 68,143 river reaches of the entire Texas Gulf, whose lateral inflow to the river network is calculated by a land surface model. RAPID allows for a matrix-based calculation of flow and volume of water in all reaches of a river network, with many thousands of reaches. Gages from the USGS National Water Information System are used to assess the quality of model calculations and to automatically determine optimal model parameters with about 1 gage available for each 160 reaches simulated. RAPID is adapted for parallel computing and has been tested on the Lonestar supercomputer (http://www.tacc.utexas.edu/resources/hpcsystems/) although challenges related to parallel computing are significant. The first author was awarded the 2008 Horton (Hydrology) Research Grant for this work.

  13. River-Based Experiential Learning: the Bear River Fellows Program

    NASA Astrophysics Data System (ADS)

    Rosenberg, D. E.; Shirley, B.; Roark, M. F.

    2012-12-01

    The Department of Civil and Environmental Engineering, Outdoor Recreation, and Parks and Recreation programs at Utah State University (USU) have partnered to offer a new, unique river-based experiential learning opportunity for undergraduates called the Bear River Fellows Program. The program allows incoming freshmen Fellows to experience a river first hand during a 5-day/4-night river trip on the nearby Bear River two weeks before the start of their first Fall semester. As part of the program, Fellows will navigate the Bear River in canoes, camp along the banks, interact with local water and environmental managers, collect channel cross section, stream flow, vegetation cover, and topological complexity data, meet other incoming freshmen, interact with faculty and graduate students, develop boating and leadership skills, problem solve, and participate as full members of the trip team. Subsequently, Fellows will get paid as undergraduate researchers during their Fall and Spring Freshman semesters to analyze, synthesize, and present the field data they collect. The program is a collaborative effort between two USU academic units and the (non-academic) division of Student Services and supports a larger National Science Foundation funded environmental modelling and management project for the lower Bear River, Utah watershed. We have advertised the program via Facebook and emails to incoming USU freshmen, received 35 applications (60% women), and accepted 5 Fellows into the program (3 female and 2 male). The river trip departs August 14, 2012. The poster will overview the Bear River Fellows Program and present qualitative and preliminary outcomes emerging from the trip and Fellows' work through the Fall semester with the field data they collect. We will also undertake more rigorous and longer longitudinal quantitative evaluation of Program outcomes (for example, in problem-solving and leadership) both in Spring 2013 and in subsequent 2013 and 2014 offerings of the

  14. 33 CFR 207.380 - Red Lake River, Minn.; logging regulations for portion of river above Thief River Falls.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... wishing to run logs on Red Lake River must provide storage booms near the head of the river to take care of said logs. (b) No one will be permitted to turn into the river at any time more logs than he can receive at his storage boom. (c) Tows arriving at the head of the river shall turn their logs into...

  15. 75 FR 51938 - Drawbridge Operation Regulation; Taunton River, Fall River and Somerset, MA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-24

    ... SECURITY Coast Guard 33 CFR Part 117 RIN 1625-AA09 Drawbridge Operation Regulation; Taunton River, Fall...) Bridge at mile 1.8, across the Taunton River between Fall River and Somerset, Massachusetts. This final..., across the Taunton River between Fall River and Somerset, Massachusetts, has a vertical clearance in...

  16. 78 FR 49918 - Drawbridge Operation Regulation; Taunton River, Fall River and Somerset, MA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ... SECURITY Coast Guard 33 CFR Part 117 RIN 1625-AA09 Drawbridge Operation Regulation; Taunton River, Fall... across the Taunton River, mile 2.1, between Fall River and Somerset, Massachusetts. The bridge owner...) entitled, ``Drawbridge Operation Regulation: Taunton River, Fall River and Somerset, MA'' in the...

  17. 29 CFR 1917.126 - River banks.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false River banks. 1917.126 Section 1917.126 Labor Regulations...) MARINE TERMINALS Terminal Facilities § 1917.126 River banks. (a) This section applies to temporary installations or temporary operations near a river bank. (b) Where working surfaces at river banks slope...

  18. 29 CFR 1917.126 - River banks.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false River banks. 1917.126 Section 1917.126 Labor Regulations...) MARINE TERMINALS Terminal Facilities § 1917.126 River banks. (a) This section applies to temporary installations or temporary operations near a river bank. (b) Where working surfaces at river banks slope...

  19. 27 CFR 9.164 - River Junction.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false River Junction. 9.164... River Junction. (a) Name. The name of the viticultural area described in this section is “River Junction.” (b) Approved maps. The appropriate maps for determining the boundaries of the River...

  20. 29 CFR 1917.126 - River banks.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false River banks. 1917.126 Section 1917.126 Labor Regulations...) MARINE TERMINALS Terminal Facilities § 1917.126 River banks. (a) This section applies to temporary installations or temporary operations near a river bank. (b) Where working surfaces at river banks slope...

  1. 27 CFR 9.164 - River Junction.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false River Junction. 9.164... River Junction. (a) Name. The name of the viticultural area described in this section is “River Junction.” (b) Approved maps. The appropriate maps for determining the boundaries of the River...

  2. 29 CFR 1917.126 - River banks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false River banks. 1917.126 Section 1917.126 Labor Regulations...) MARINE TERMINALS Terminal Facilities § 1917.126 River banks. (a) This section applies to temporary installations or temporary operations near a river bank. (b) Where working surfaces at river banks slope...

  3. PCBs in the Harlem River

    NASA Astrophysics Data System (ADS)

    Wang, J.

    2012-12-01

    Polychlorinated biphenyls (PCBs) are persistent, toxic and bioaccumulated contaminants of great environmental concern. PCB is a tracer of wastewater, stormwater and CSOs inputs; PCBs contamination of fish is a main environmental concern for the Harlem River. PCBs in the Harlem River are from combined sewer overflows (CSOs), stormwater runoff, wastewater, as well as upper Hudson GE (General Electric at Fort Edward)'s release. PCBs affect human health mostly from contaminated fish consumption. Many research focused on PCBs in the Hudson River and New York/New Jersey Harbor. However, PCBs source, transport and environmental impact in the Harlem River-a natural straight that connects the Hudson River and the East River, had not been well studied. In this research, water sample were collected from the Harlem River and analyzed PCBs by HR GC/MS (High resolution gas chromatography mass spectrophotometer). Preliminary results showed that certain PCBs congeners in the water column. Results also indicated that nutrients (phosphorus and ammonia) as well as bacteria levels exceeded EPA standards: Total phosphorus-10μg/L, total nitrogen-0.38mg/L; E.Coli-126 MPN/100ml, Enterococcus- 104MPN/100ml, Fecal Coliform-200 MPN/100ml. This research is under process, and more results could give further detail in near future. This research will help improve water quality of the Harlem River, improve environmental health and raise environmental awareness.SO tank Nutrient and bacterial levels of selected sites in the Harlem RiverCSO: Combined Sewer OverflowWWTP: Waste Water Treatment Plant

  4. Ice Jams the Ob River

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Russia's Ob River flows from south to north, and each summer, it thaws in the same direction. The result is that an ice jam sits downstream from thawed portions of the river, which is laden with heavy runoff from melted snow. On June 29, 2007, the Moderate Resolution Imaging Spectroradiometer (MODIS) flying on NASA's Terra satellite captured this image of the almost completely thawed Ob River. The scene is typical for early summer. South of the ice jam, the Gulf of Ob is swollen with pent-up run-off, and upstream from that, the river is widened as well. Unable to carve through frozen land, the river has little choice but to overflow its banks. For a comparison of early summer and autumn conditions, see Flooding on the Ob River in the Earth Observatory's Natural Hazards section. Besides the annual overflow, this image captures other circumstances of early summer. Sea ice is retreating from the Kara Sea. A lingering line of snow cover snakes its way along the Ob River, to the west. And while the land is lush and green in the south, it appears barren and brown in the north. Near the mouth of the river and the Kara Sea, the land is cold-adapted tundra, with diminutive plants and a short growing season. Just as the ice plugging the river had yet to thaw in the Far North's short summer, the tundra had not yet to greened up either. In this image it still appears lifeless beige. NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center

  5. Lena River, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This pair of true- and false-color images from the Moderate Resolution Imaging Spectroradiometer (MODIS) from June 28, 2002, shows numerous burn scars dotting the northern Siberian landscape along the Lena River. In the true-color image, the burn scars appear dark grayish-brown, while in the false-color image they appear red, as does the bare exposed soil of the Verkhoyansk Mountain Range to the east of the north-flowing Lena. A tinge of blue along the mountains in the false-color image means there is some lingering snow or ice, and that the bare soil is due to spring's late arrival there, and not to burn scars. At the top, sea ice still fills the Laptev Sea. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  6. River history and tectonics.

    PubMed

    Vita-Finzi, C

    2012-05-13

    The analysis of crustal deformation by tectonic processes has gained much from the clues offered by drainage geometry and river behaviour, while the interpretation of channel patterns and sequences benefits from information on Earth movements before or during their development. The interplay between the two strands operates at many scales: themes which have already benefited from it include the possible role of mantle plumes in the breakup of Gondwana, the Cenozoic development of drainage systems in Africa and Australia, Himalayan uplift in response to erosion, alternating episodes of uplift and subsidence in the Mississippi delta, buckling of the Indian lithospheric plate, and changes in stream pattern and sinuosity along individual alluvial channels subject to localized deformation. Developments in remote sensing, isotopic dating and numerical modelling are starting to yield quantitative analyses of such effects, to the benefit of geodymamics as well as fluvial hydrology.

  7. [Characteristics of absorption and fluorescence spectra of dissolved organic matter from confluence of rivers: case study of Qujiang River-Jialing River and Fujiang River-Jialing River].

    PubMed

    Yan, Jin-Long; Jiang, Tao; Gao, Jie; Wei, Shi-Qiang; Lu, Song; Liu, Jiang

    2015-03-01

    Three-dimensional fluorescence spectroscopy combined with ultraviolet-visible (UV-Vis) absorption spectra was used to investigate the change characteristics of dissolved organic matter (DOM) in confluences water of Qujiang River-Jialing River and Fujiang River-Jialing River, respectively. The results suggested that DOM showed a significant terrestrial input signal in all the sampling sites, FI < 1.4, HIX > 0.8, possibly representing remarkable signals of humus resulted from humic-like component. Moreover, the mixing zone of this study showed a non-conservative mixed behavior, which had a limited contribution, and was not the dominant factor to interpret the change characteristics of DOM in confluences zones. Different land-use types along all the rivers had an obvious impact on DOM inputs. Results of cluster analysis showed that a higher degree of aromaticity and humification components was observed as the predominant contributor to DOM when the land-use type was forest and farmland ecosystem, for example the confluences of Qujiang River-Jialing River. On the other hand, high concentrations of DOM with relative simple structures were found in the water when the urban land-use type was predominant, for example the confluences of Fujiang River-Jialing River. Meanwhile, a new fluorescent signal of protein-like components (peak T) appeared, which manifested a significant effect on the water quality resulted from anthropogenic activities.

  8. Arctic River organic matter transport

    NASA Astrophysics Data System (ADS)

    Raymond, Peter; Gustafsson, Orjan; Vonk, Jorien; Spencer, Robert; McClelland, Jim

    2016-04-01

    Arctic Rivers have unique hydrology and biogeochemistry. They also have a large impact on the Arctic Ocean due to the large amount of riverine inflow and small ocean volume. With respect to organic matter, their influence is magnified by the large stores of soil carbon and distinct soil hydrology. Here we present a recap of what is known of Arctic River organic matter transport. We will present a summary of what is known of the ages and sources of Arctic River dissolved and particulate organic matter. We will also discuss the current status of what is known about changes in riverine organic matter export due to global change.

  9. Nitrate Trends in Minnesota Rivers

    USGS Publications Warehouse

    Wall, Dave; Christopherson, Dave; Lorenz, Dave; Martin, Gary

    2013-01-01

    The objective of this study was to assess long-term trends (30 to 35 years) of flow-adjusted concentrations of nitrite+nitrate-N (hereinafter referred to as nitrate) in a way that would allow us to discern changing trends. Recognizing that these trends are commonly different from one river to another river and from one part of the state to another, our objective was to examine as many river monitoring sites across the state as possible for which sufficient long term streamflow and concentration data were available.

  10. Status of river herring stocks in large rivers

    USGS Publications Warehouse

    Schmidt, R.E.; Jessop, B.M.; Hightower, J.E.

    2003-01-01

    We examined long-term data sets from large rivers in the northern, central, and southern parts of the ranges of anadromous river herring (alewife Alosa pseudoharengus and blueback herring A. aestivalis) to assess the current status of these species and for evidence of fishery-induced effects on their demographic characteristics. Both species show signs of overexploitation in all rivers examined, such as reductions in mean age, decreases in percentage of returning spawners, and decreases in abundance. These two species should be managed separately since exploitation within a given river is often biased toward one or the other and there are enough differences in their biology so that a single management option will affect them differently. These species are not distinguished in commercial catches, which hinders understanding of their exploitation. ?? 2003 by the American Fisheries Society.

  11. Red River of the North Reconnaissance Report: Turtle River Subbasin.

    DTIC Science & Technology

    1980-12-01

    formed by glacial Lake Agassiz . The major streamwater features are the Turtle River and its two branches: the North Branch and the South Branch. The...spread out over the nearly level, south-sloping Elk River delta (formed in glacial Lake Agassiz ). The area around Manvel is an essentially flat...transected by a series of elevated geological features called beach ridges, or strandlines, which are associated with the formation of glacial Lake Agassiz

  12. Red River of the North, Reconnaissance Report: Main Stem Subbasin.

    DTIC Science & Technology

    1980-12-01

    different from Report) IS. SUPPLEMENTARY NOTES Bois de Sious-Mustinka Rivers; Buffalo River; Devils Lake; Elm River ; Forest River; Goose River; Maple River...corridor for animals moving north and south along the Red River . Forests afford breeding and nesting areas for birds and rank second only 2to wetlands

  13. Flooding on California's Russian River: Role of atmospheric rivers

    USGS Publications Warehouse

    Ralph, F.M.; Neiman, P.J.; Wick, G.A.; Gutman, S.I.; Dettinger, M.D.; Cayan, D.R.; White, A.B.

    2006-01-01

    Experimental observations collected during meteorological field studies conducted by the National Oceanic and Atmospheric Administration near the Russian River of coastal northern California are combined with SSM/I satellite observations offshore to examine the role of landfalling atmospheric rivers in the creation of flooding. While recent studies have documented the characteristics and importance of narrow regions of strong meridional water vapor transport over the eastern Pacific Ocean (recently referred to as atmospheric rivers), this study describes their impact when they strike the U.S. West Coast. A detailed case study is presented, along with an assessment of all 7 floods on the Russian River since the experimental data were first available in October 1997. In all 7 floods, atmospheric river conditions were present and caused heavy rainfall through orographic precipitation. Not only do atmospheric rivers play a crucial role in the global water budget, they can also lead to heavy coastal rainfall and flooding, and thus represent a key phenomenon linkingweather and climate. Copyright 2006 by the American Geophysical Union.

  14. Elwha River dam removal-Rebirth of a river

    USGS Publications Warehouse

    Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

    2011-01-01

    After years of planning for the largest project of its kind, the Department of the Interior will begin removal of two dams on the Elwha River, Washington, in September 2011. For nearly 100 years, the Elwha and Glines Canyon Dams have disrupted natural processes, trapping sediment in the reservoirs and blocking fish migrations, which changed the ecology of the river downstream of the dams. All five Pacific salmon species and steelhead-historically present in large numbers-are locally extirpated or persist in critically low numbers. Upstream of the dams, more than 145 kilometers of pristine habitat, protected inside Olympic National Park, awaits the return of salmon populations. As the dams are removed during a 2-3 year project, some of the 19 million cubic meters of entrapped sediment will be carried downstream by the river in the largest controlled release of sediment into a river and marine waters in history. Understanding the changes to the river and coastal habitats, the fate of sediments, and the salmon recolonization of the Elwha River wilderness will provide useful information for society as future dam removals are considered.

  15. Quaternary Morphodynamics for two large rivers: the Fly River, PNG, and the Mekong River, Cambodia.

    NASA Astrophysics Data System (ADS)

    Aalto, R. E.; Lauer, J. W.; Darby, S. E.; Goni, M. A.; Dietrich, W. E.

    2014-12-01

    During glacial marine transgressions, sediment & carbon are deposited due to the infilling of lowland fluvial systems, material that is then largely removed during ensuing regressions. Measuring & modelling these processes would help quantify the amount, timing, & preservation of these materials, providing insight into the morphodynamics of lowland fluvial systems in response to sea level change. We investigated the infilling dynamics of the Fly and Strickland Rivers, Papua New Guinea. Field data include: 14C dated deep cores recording base level evolution over the Holocene, sonar imaging of floodbasin stratigraphy, and the observations of blocked valley lakes and weathered erosional remnants from LGM conditions. Similar research was conducted on the Mekong River, Cambodia, where we have imaged basin fill stratigraphy and recorded the extent of blocked valley lakes. Such field data provide tantalizing empirical glimpses into the landscapes & flux buffering exhibited by large tropical rivers during glacial-interglacial transitions. We upscale our observations by modelling river system evolution, employing a GpU Lowland Landscape Evolution Model (GULLEM) to predict the evolution of the entire basin. A novel & powerful (>10 Tflops on an inexpensive computer) simulator, GULLEM models morphodynamics and estimates the accommodation space subsequently infilled during marine transgressions by representing a range of geomorphic processes, including: river & tributary incision, non-linear diffusion, sea level and isostatic change, hydraulic geometry, tectonic deformation, sediment production, transport & deposition, & tracking of the resulting stratigraphy. GULLEM's vectorized approach allows for massively parallel operation on GPUs (Graphics Processing Unit), making it practical to model coupled fluvial-landscape evolution for complex lowland river systems over large temporal and spatial scales. Our combined approach affords estimates for the timing and budgets of sediment

  16. National Rivers and Streams Assessment

    EPA Pesticide Factsheets

    The NRSA is a collaborative, statistical survey of the nation's rivers and streams. It is one of four national surveys that EPA and its partners conduct to assess the condition and health of the nation's water resources.

  17. Remote sensing at Savannah River

    SciTech Connect

    Corey, J.C.

    1986-01-01

    The paper discusses remote sensing systems used at the Savannah River Plant. They include three ground-based systems: ground penetrating radar, sniffers, and lasers; and four airborne systems: multispectral photography, lasers, thermal imaging, and radar systems. (ACR)

  18. Missouri River, Natural Resources Bibliography.

    DTIC Science & Technology

    1997-07-01

    Dissertation Abstracts, UnCover, Agricola , and terrestrial habitats adjacent to the river resulted in a variety of bibliographies available on the Internet...106- 232. BUSINESS RESEARCH BUREAU. 1960. 16. Recreational survey of Lewis and Clark Lake and Fort Randall Reservoir. Bus. Res. Bur., 224. BURGESS RL...and 834. HORNER AND SHIFRIN I. 1987. Flood protection zoogeography of the Missouri River Valley in for Missouri Bottoms. Prepared for Business North

  19. 9. LOOKING NW FROM EAST BANK OF SCHUYLKILL RIVER. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. LOOKING NW FROM EAST BANK OF SCHUYLKILL RIVER. - Philadelphia & Reading Railroad, Schuylkill River Viaduct, Spanning Schuylkill River, southeast of Roosevelt Boulevard Bridge, Philadelphia, Philadelphia County, PA

  20. 17. OVERVIEW FROM WEST BANK OF SCHUYLKILL RIVER, LOOKING EAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. OVERVIEW FROM WEST BANK OF SCHUYLKILL RIVER, LOOKING EAST - Philadelphia & Reading Railroad, Schuylkill River Viaduct, Spanning Schuylkill River, southeast of Roosevelt Boulevard Bridge, Philadelphia, Philadelphia County, PA

  1. 11. OVERVIEW FROM WEST BANK OF SCHUYLKILL RIVER, LOOKING EAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. OVERVIEW FROM WEST BANK OF SCHUYLKILL RIVER, LOOKING EAST. - Philadelphia & Reading Railroad, Schuylkill River Viaduct, Spanning Schuylkill River, southeast of Roosevelt Boulevard Bridge, Philadelphia, Philadelphia County, PA

  2. Ecosystem Services of Rivers: The Don River (Russian Federation) and the Roanoke River (USA)

    EPA Science Inventory

    The concept of ecosystem services recognizes the services, and benefits, provided to people by ecosystems. River systems provide many services to people, including freshwater provisioning, carbon storage, fisheries, recreation, transportation, and biodiversity. Here, we review th...

  3. From eutrophic lake to river: phytoplankton composition changes in river-lake system (Tanglangchuan River, China)

    NASA Astrophysics Data System (ADS)

    Yu, Qian; Chen, Yongcan; Liu, Zhaowei; Zhu, Dejun; van de Giesen, Nick

    2014-05-01

    Due to the fact that the Dianchi Lake is a hypereutrophic lake, we assume it is a potential source of cyanobacteria seed contributing to harmful algal blooms in the upper reach of the Tanglangchuan River (China). However, cyanobacteria, unlikely to survive in the short-retention-time river, are possibly replaced by other fast-growing algae along the river. To determine longitudinal changes of phytoplankton structures from Dianchi Lake to downstream Tanglangchuan River, samplings were carried out in June and September 2013 at 7 different stations. Among these stations, two of them are located in the mouth of Dianchi Lake (D1~D2) while the remaining five are along the main stream of the Tanglangchuan River (T1~T5). Then phytoplankton species were defined. We found that in June cyanobacteria dominated with more than 95% of the total cells in D1 and D2. The cyanobacteria sustained a long distance from T1 to T4 with a clear dominance of the total cells from 85.6% to 90.4%. However, in the last station (T5) which is located about 100km downstream the mouth of the Dianchi Lake, chlorophytes and bacillariophytes took the place of cyanobacteria and dominated (56.3% of the cells were chlorophytes and 27.1% were bacillariophytes). In autumn, the cyanobacteria dominated from D1 to T5 but the percentage and biomass of the cyanobacteria decreased along the river. The dominance of the cyanobacteria in the upper reach of the river indicates that the Dianchi Lake provides the cyanobacteria seed to the downstream river. Additionally, the transition of the algae dominance in the lower reach suggests that longitudinal changes in phytoplankton composition do exist. In view of the high concentration of total nitrogen and total phosphorus, changes of flow velocity and residence time should be key factors causing spatial succession.

  4. Valley evolution by meandering rivers

    NASA Astrophysics Data System (ADS)

    Limaye, Ajay Brian Sanjay

    Fluvial systems form landscapes and sedimentary deposits with a rich hierarchy of structures that extend from grain- to valley scale. Large-scale pattern formation in fluvial systems is commonly attributed to forcing by external factors, including climate change, tectonic uplift, and sea-level change. Yet over geologic timescales, rivers may also develop large-scale erosional and depositional patterns that do not bear on environmental history. This dissertation uses a combination of numerical modeling and topographic analysis to identify and quantify patterns in river valleys that form as a consequence of river meandering alone, under constant external forcing. Chapter 2 identifies a numerical artifact in existing, grid-based models that represent the co-evolution of river channel migration and bank strength over geologic timescales. A new, vector-based technique for bank-material tracking is shown to improve predictions for the evolution of meander belts, floodplains, sedimentary deposits formed by aggrading channels, and bedrock river valleys, particularly when spatial contrasts in bank strength are strong. Chapters 3 and 4 apply this numerical technique to establishing valley topography formed by a vertically incising, meandering river subject to constant external forcing---which should serve as the null hypothesis for valley evolution. In Chapter 3, this scenario is shown to explain a variety of common bedrock river valley types and smaller-scale features within them---including entrenched channels, long-wavelength, arcuate scars in valley walls, and bedrock-cored river terraces. Chapter 4 describes the age and geometric statistics of river terraces formed by meandering with constant external forcing, and compares them to terraces in natural river valleys. The frequency of intrinsic terrace formation by meandering is shown to reflect a characteristic relief-generation timescale, and terrace length is identified as a key criterion for distinguishing these

  5. Rivers, runoff, and reefs

    USGS Publications Warehouse

    McLaughlin, C.J.; Smith, C.A.; Buddemeier, R.W.; Bartley, J.D.; Maxwell, B.A.

    2003-01-01

    The role of terrigenous sediment in controlling the occurrence of coral reef ecosystems is qualitatively understood and has been studied at local scales, but has not been systematically evaluated on a global-to-regional scale. Current concerns about degradation of reef environments and alteration of the hydrologic and sediment cycles place the issue at a focal point of multiple environmental concerns. We use a geospatial clustering of a coastal zone database of river and local runoff identified with 0.5?? grid cells to identify areas of high potential runoff effects, and combine this with a database of reported coral reef locations. Coastal cells with high runoff values are much less likely to contain reefs than low runoff cells and GIS buffer analysis demonstrates that this inhibition extends to offshore ocean cells as well. This analysis does not uniquely define the effects of sediment, since salinity, nutrients, and contaminants are potentially confounding variables also associated with runoff. However, sediment effects are likely to be a major factor and a basis is provided for extending the study to higher resolution with more specific variables. ?? 2003 Elsevier B.V. All rights reserved.

  6. Stratigraphic cross sections of the Niobrara interval of the Cody Shale and associated rocks in the Wind River Basin, central Wyoming

    USGS Publications Warehouse

    Finn, Thomas M.

    2017-02-07

    The Wind River Basin in Wyoming is one of many structural and sedimentary basins that formed in the Rocky Mountain foreland during the Laramide orogeny. The basin is nearly 200 miles long, 70 miles wide, and encompasses about 7,400 square miles in central Wyoming. The basin is bounded by the Washakie Range, Owl Creek uplift, and southern Bighorn Mountains on the north, the Casper arch on the east, the Granite Mountains on the south, and Wind River Range on the west.Many important conventional oil and gas fields producing from reservoirs ranging in age from Mississippian through Tertiary have been discovered in this basin. In addition, an extensive unconventional overpressured basin-centered gas accumulation has been identified in Cretaceous and Tertiary strata in the deeper parts of the basin. It has long been suggested that various Upper Cretaceous marine shales, including the Cody Shale, are the principal hydrocarbon source rocks for many of these accumulations. With recent advances and success in horizontal drilling and multistage fracture stimulation, there has been an increase in exploration and completion of wells in these marine shales in other Rocky Mountain Laramide basins that were traditionally thought of only as hydrocarbon source rocks.The two stratigraphic cross sections presented in this report were constructed as part of a project carried out by the U.S. Geological Survey to characterize and evaluate the undiscovered continuous (unconventional) oil and gas resources of the Niobrara interval of the Upper Cretaceous Cody Shale in the Wind River Basin in central Wyoming. The primary purpose of the cross sections is to show the stratigraphic relationship of the Niobrara equivalent strata and associated rocks in the lower part of the Cody Shale in the Wind River Basin. These two cross sections were constructed using borehole geophysical logs from 37 wells drilled for oil and gas exploration and production, and one surface section along East Sheep Creek

  7. Yazoo River Basin (Lower Mississippi River) Hydrologic Observatory

    NASA Astrophysics Data System (ADS)

    Cheng, A.; Davidson, G.; Altinakar, M.; Holt, R.

    2004-12-01

    The proposed Yazoo River Basin Hydrologic Observatory consists of the 34,000 square km Yazoo River watershed in northwestern Mississippi and a 320 km segment of the Mississippi River separated from the watershed by a manmade levee. Discharge from the basin flows from the Yazoo River into the Mississippi River north of Vicksburg, MS. Major streams within the basin include the Yazoo, Tallahatchie, Yalobusha, Coldwater, Yocona, and Big Sunflower Rivers. Four large flood control reservoirs (Arkabutla, Enid, Sardis, and Grenada) and two national forests (Delta and Holly Springs) are also located within the basin. The watershed is divided between upland forested hills and intensively cultivated lowlands. The lowland area, locally known as the "Delta", lies on the ancestral floodplain of the Mississippi River. Flooding by the Mississippi River was once a common event, but is now limited by the levee system. Abundant wetlands occupy abandoned stream channels throughout the Delta. The Yazoo River Basin has many unique features that make it an attractive site for an Hydrologic Observatory. Example features and issues of scientific interest include: 1) Extensive system of levees which have altered recharge to the regional aquifer, shifted population centers, and created backwater flooding areas. 2) Abundant wetlands with a century-long history of response to agricultural sediment and chemical fluxes. 3) Erosion of upland streams, and stream sediment loads that are the highest in the nation. 4) Groundwater mining in spite of abundant precipitation due to a regional surface clay layer that limits infiltration. 5) A history of agricultural Best Management Practices enabling evaluation of the effectiveness of such measures. 6) Large scale catfish farming with heavy reliance on groundwater. 7) Near enough to the Gulf coast to be impacted by hurricane events. 8) Already existing network of monitoring stations for stream flow, sediment-load, and weather, including complete coverage

  8. Turbulent forces within river plumes affect spread

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Atreyee

    2012-08-01

    When rivers drain into oceans through narrow mouths, hydraulic forces squeeze the river water into buoyant plumes that are clearly visible in satellite images. Worldwide, river plumes not only disperse freshwater, sediments, and nutrients but also spread pollutants and organisms from estuaries into the open ocean. In the United States, the Columbia River—the largest river by volume draining into the Pacific Ocean from North America—generates a plume at its mouth that transports juvenile salmon and other fish into the ocean. Clearly, the behavior and spread of river plumes, such as the Columbia River plume, affect the nation's fishing industry as well as the global economy.

  9. The economic value of Trinity River water

    USGS Publications Warehouse

    Douglas, A.J.; Taylor, J.G.

    1999-01-01

    The Trinity River, largest tributary of the Klamath River, has its head-waters in the Trinity Alps of north-central California. After the construction of Trinity Dam in 1963, 90% of the Trinity River flow at Lewiston was moved to the Sacramento River via the Clear Creek Tunnel, a manmade conduit. Hydropower is produced at four installations along the route of Trinity River water that is diverted to the Sacramento River, and power production at three of these installations would diminish if no Trinity River water were diverted to the Sacramento River. After Trinity River water reaches the Sacramento River, it flows toward the Sacramento-San Joaquin Delta and San Francisco Bay. Trinity River water is pumped via Bureau of Reclamation canals and pumps to the northern San Joaquin Valley, where it is used for irrigated agriculture. The social cost of putting more water down the Trinity River is the sum of the value of the foregone consumer surplus from hydropower production as well as the value of the foregone irrigation water. Sharply diminished instream flows have also severely affected the size and robustness of Trinity River salmon, steelhead, shad and sturgeon runs. Survey data were used to estimate the non-market benefits of augmenting Trinity River instream flows by letting more water flow down the Trinity and moving less water to the Sacramento River. Preservation benefits for Trinity River instream flows and fish runs are $803 million per annum for the scenario that returns the most water down the Trinity River, a value that greatly exceeds the social cost estimate.The Trinity River, largest tributary of the Klamath River, has its headwaters in the Trinity Alps of north-central California. After the construction of Trinity Dam in 1963, 90% of the Trinity River flow at Lewiston was moved to the Sacramento River via the Clear Creek Tunnel, a manmade conduit. Hydropower is produced at four installations along the route of Trinity River water that is diverted to the

  10. Flood trends and river engineering on the Mississippi River system

    USGS Publications Warehouse

    Pinter, N.; Jemberie, A.A.; Remo, J.W.F.; Heine, R.A.; Ickes, B.S.

    2008-01-01

    Along >4000 km of the Mississippi River system, we document that climate, land-use change, and river engineering have contributed to statistically significant increases in flooding over the past 100-150 years. Trends were tested using a database of >8 million hydrological measurements. A geospatial database of historical engineering construction was used to quantify the response of flood levels to each unit of engineering infrastructure. Significant climate- and/or land use-driven increases in flow were detected, but the largest and most pervasive contributors to increased flooding on the Mississippi River system were wing dikes and related navigational structures, followed by progressive levee construction. In the area of the 2008 Upper Mississippi flood, for example, about 2 m of the flood crest is linked to navigational and flood-control engineering. Systemwide, large increases in flood levels were documented at locations and at times of wing-dike and levee construction. Copyright 2008 by the American Geophysical Union.

  11. Sacramento River Water Treatment Plant Intake Pier & Access Bridge, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA

  12. 8. Detail view of girders and Southernmost river pier, Southernmost ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Detail view of girders and Southernmost river pier, Southernmost deck-girder span, underside of deck, looking North - Elk River Bridge, Spanning Elk River at Main Street, Elk River, Sherburne County, MN

  13. 1. SNAKE RIVER VALLEY IRRIGATION DISTRICT DAM, VIEW OF NORTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. SNAKE RIVER VALLEY IRRIGATION DISTRICT DAM, VIEW OF NORTH ELEVATION OF INTAKE ON EAST SIDE OF DAM - Snake River Valley Irrigation District, East Side of Snake River (River Mile 796), Shelley, Bingham County, ID

  14. Past, present, and future concepts in large river ecology

    USGS Publications Warehouse

    Johnson, B.L.; Richardson, W.B.; Naimo, T.J.

    1995-01-01

    How rivers function and how human activities influence river processes. Many important questions are likely to require natural experiments or large-scale manipulations that compare rivers or river reaches.

  15. Intermittent ephemeral river-breaching

    NASA Astrophysics Data System (ADS)

    Reniers, A. J.; MacMahan, J. H.; Gallagher, E. L.; Shanks, A.; Morgan, S.; Jarvis, M.; Thornton, E. B.; Brown, J.; Fujimura, A.

    2012-12-01

    In the summer of 2011 we performed a field experiment in Carmel River State Beach, CA, at a time when the intermittent natural breaching of the ephemeral Carmel River occurred due to an unusually rainy period prior to the experiment associated with El Nino. At this time the river would fill the lagoon over the period of a number of days after which a breach would occur. This allowed us to document a number of breaches with unique pre- and post-breach topographic surveys, accompanying ocean and lagoon water elevations as well as extremely high flow (4m/s) velocities in the river mouth during the breaching event. The topographic surveys were obtained with a GPS-equipped backpack mounted on a walking human and show the evolution of the river breaching with a gradually widening and deepening river channel that cuts through the pre-existing beach and berm. The beach face is qualified as a steep with an average beach slope of 1:10 with significant reflection of the incident waves (MacMahan et al., 2012). The wave directions are generally shore normal as the waves refract over the deep canyon that is located offshore of the beach. The tide is mixed semi-diurnal with a range on the order of one meter. Breaching typically occurred during the low-low tide. Grain size is highly variable along the beach with layers of alternating fine and coarse material that could clearly be observed as the river exit channel was cutting through the beach. Large rocky outcroppings buried under the beach sand are also present along certain stretches of the beach controlling the depth of the breaching channel. The changes in the water level measured within the lagoon and the ocean side allows for an estimate of the volume flux associated with the breach as function of morphology, tidal elevation and wave conditions as well as an assessment of the conditions and mechanisms of breach closure, which occurred on the time scale of O(0.5 days). Exploratory model simulations will be presented at the

  16. Colloids in the River Inn

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Baumann, Thomas

    2014-05-01

    In the light of an increasing number of technical applications using nanoparticles and reports of adverse effects of engineered nanoparticles, research on the occurrence and stability of particles in all compartments has to be intensified. Colloids in river water represent the geologic setting, environmental conditions, and the anthropogenic use in its catchment. The river not only acts as a sink for nanoparticles but also as the source term due to exchange in the hyporheic zone and in bank filtration setups. The concentration, size distribution and elemental composition of particles in the River Inn were studied from the source in the Swiss Alps to the river mouth at Passau. Samples were collected after each tributary from a sub-catchment and filtered on-site. The elemental composition was determined after acid digestion with ICP/MS. SEM/EDX analyses provided morphological and elemental information for single particles. A complementary chemical analysis of the river water was performed to assess the geochemical stability of indvidual particles. Particles in the upper, rural parts mainly reveal changes in the geological setting of the tributary catchments. Not unexpectedly, particles originating from crystalline rocks, were more stable than particles originating from calcareous rocks. Anthropogenic and industrial influences increase in the lower parts. This went together with a change of the size distribution, an increase of the number of organic particles, and a decrease of the microfauna. Interestingly, specific leisure activities in a sub-catchment, like extensive downhill skiing, manifest itself in the particle composition.

  17. Towards a sociogeomorphology of rivers

    NASA Astrophysics Data System (ADS)

    Ashmore, Peter

    2015-12-01

    While human impacts on rivers and other landforms have long been a component of geomorphic research, little of this work explicitly includes insights into human agency from social science or recognises that in many cases rivers can be considered to be hybrid co-productions or 'socio-natures'. A socio-geomorphic approach proposed here has parallels with some aspects of sociohydrology and can extend and enrich existing geomorphic explanations of the morphology of, for example, urban rivers by explicitly recognising and working with the co-evolution of the human and natural systems. Examples from recent literature illustrate ways in which these relationships can be understood and analyzed, showing a range of socio-natural influences in particular contexts that have material consequences for river morphology and recognising that events in the system have many forms. The approach recognises the importance of contingency in time and place together with the role and nature of both local and global knowledge. An important element of this approach is that it provides ways for understanding the nature, position and intention of geomorphic and other scientific interventions as part of the system, for example in the case of river restoration. This also leads to the need for reflexivity by geomorphologists and reconsideration of the nature of geomorphological knowledge by those involved in such work and with respect to sociogeomorphology as a whole.

  18. Morphodynamics: Rivers beyond steady state

    NASA Astrophysics Data System (ADS)

    Church, M.; Ferguson, R. I.

    2015-04-01

    The morphology of an alluvial river channel affects the movement of water and sediment along it, but in the longer run is shaped by those processes. This interplay has mostly been investigated empirically within the paradigm of Newtonian mechanics. In rivers, this has created an emphasis on equilibrium configurations with simple morphology and uniform steady flow. But transient adjustment, whether between equilibrium states or indefinitely, is to be expected in a world in which hydrology, sediment supply, and base level are not fixed. More fundamentally, water flows and all the phenomena that accompany them are inherently unsteady, and flows in natural channels are characteristically nonuniform. The morphodynamics of alluvial river channels is the striking consequence. In this paper, we develop the essential connection between the episodic nature of bed material transport and the production of river morphology, emphasizing the fundamental problems of sediment transport, the role of bar evolution in determining channel form, the role of riparian vegetation, and the wide range of time scales for change. As the key integrative exercise, we emphasize the importance of physics-based modeling of morphodynamics. We note consequences that can be of benefit to society if properly understood. These include the possibility to better be able to model how varying flows drive morphodynamic change, to understand the influence of the sediments themselves on morphodynamics, and to recognize the inherent necessity for rivers that transport bed material to deform laterally. We acknowledge pioneering contributions in WRR and elsewhere that have introduced some of these themes.

  19. Tsunami Bores in Kitakami River

    NASA Astrophysics Data System (ADS)

    Tolkova, Elena; Tanaka, Hitoshi

    2016-12-01

    The 2011 Tohoku tsunami entered the Kitakami river and propagated there as a train of shock waves, recorded with a 1-min interval at water level stations at Fukuchi, Iino, and the weir 17.2 km from the mouth, where the bulk of the wave was reflected back. The records showed that each bore kept its shape and identity as it traveled a 10.9-km-path Fukuchi-Iino-weir-Iino. Shock handling based on the cross-river integrated classical shock conditions was applied to reconstruct the flow velocity time histories at the measurement sites, to estimate inflow into the river at each site, to evaluate the wave heights of incident and reflected tsunami bores near the weir, and to estimate propagation speed of the individual bores. Theoretical predictions are verified against the measurements. We discuss experiences of exercising the shock conditions with actual tsunami measurements in the Kitakami river, and test applicability of the shallow-water approximation for describing tsunami bores with heights ranging from 0.3 to 4 m in a river segment with a depth of 3-4 m.

  20. The River Danube: An Examination of Navigation on the River

    NASA Astrophysics Data System (ADS)

    Cooper, R. W.

    One of the definitions of Navigation that gets little attention in this Institute is (Oxford English Dictionary), and which our French friends call La Navigation. I have always found this subject fascinating, and have previously navigated the Rivers Mekong, Irrawaddy, Hooghly, Indus, Shatt-al-Arab, Savannah and RhMainKanal (RMDK) and the River Danube, a distance of approximately 4000 km. This voyage has only recently become possible with the opening of the connecting RMDK at the end of 1992, but has been made little use of because of the civil war in the former Yugoslavia.

  1. Mighty Microbes Where Rivers Run

    ScienceCinema

    Stegen, James

    2016-07-12

    Microbes and their influential role in Earth’s climate take center stage in the area where river water and groundwater mix – an area known as the hyporheic zone. PNNL ecologist James Stegen discusses his team’s research in his “laboratory” – the zone along the Columbia, one of the nation’s largest rivers. It’s a squishy, porous lab, better known for soaking feet than serving as the “river’s liver.” Read more: http://www.pnl.gov/news/release.aspx?...

  2. Nelson River and Hudson Bay

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Rivers that empty into large bodies of water can have a significant impact on the thawing of nearshore winter ice. This true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from May 18, 2001, shows the Nelson River emptying spring runoff from the Manitoba province to the south into the southwestern corner of Canada's Hudson Bay. The warmer waters from more southern latitudes hasten melting of ice near the shore, though some still remained, perhaps because in shallow coastal waters, the ice could have been anchored to the bottom. High volumes of sediment in the runoff turned the inflow brown, and the rim of the retreating ice has taken on a dirty appearance even far to the east of the river's entrance into the Bay. The sediment would have further hastened the melting of the ice because its darker color would have absorbed more solar radiation than cleaner, whiter ice. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  3. Grays River Watershed Geomorphic Analysis

    SciTech Connect

    Geist, David R

    2005-04-30

    This investigation, completed for the Pacific Northwest National Laboratory (PNNL), is part of the Grays River Watershed and Biological Assessment commissioned by Bonneville Power Administration under project number 2003-013-00 to assess impacts on salmon habitat in the upper Grays River watershed and present recommendations for habitat improvement. This report presents the findings of the geomorphic assessment and is intended to support the overall PNNL project by evaluating the following: The effects of historical and current land use practices on erosion and sedimentation within the channel network The ways in which these effects have influenced the sediment budget of the upper watershed The resulting responses in the main stem Grays River upstream of State Highway 4 The past and future implications for salmon habitat.

  4. 33 CFR 117.755 - Shrewsbury River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.755 Shrewsbury River. The draw of the Monmouth County highway bridge at mile 4.0, across the Shrewsbury River at Sea Bright, New Jersey,...

  5. 33 CFR 117.755 - Shrewsbury River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.755 Shrewsbury River. The draw of the Monmouth County highway bridge at mile 4.0, across the Shrewsbury River at Sea Bright, New Jersey,...

  6. 33 CFR 117.755 - Shrewsbury River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.755 Shrewsbury River. The draw of the Monmouth County highway bridge at mile 4.0, across the Shrewsbury River at Sea Bright, New Jersey,...

  7. 33 CFR 117.755 - Shrewsbury River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.755 Shrewsbury River. The draw of the Monmouth County highway bridge at mile 4.0, across the Shrewsbury River at Sea Bright, New Jersey,...

  8. Savannah River Site Environmental Implentation Plan

    SciTech Connect

    Not Available

    1989-08-01

    This report describes the organizational responsibilities for the Savannah River Site Environmental program. Operations, Engineering and projects, Environment, safety, and health, Quality assurance, and the Savannah River Laboratory are described.

  9. Siletz River nutrients: Effects of biosolids application

    EPA Science Inventory

    Stream water nutrients were measured in the Siletz River, Oregon, with the goal of comparing dissolved nutrient concentrations, primarily the nitrogenous nutrients nitrate and ammonium, with previously collected data for the Yaquina and Alsea Rivers for the nutrient criteria prog...

  10. 77 FR 45653 - Yakima River Basin Conservation Advisory Group; Yakima River Basin Water Enhancement Project...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-01

    ... Conservation Advisory Group; Yakima River Basin Water Enhancement Project, Yakima, WA AGENCY: Bureau of... Committee Act, the Yakima River Basin Conservation Advisory Group, Yakima River Basin Water Enhancement... River Basin Water Conservation Program. DATES: The meeting will be held on Tuesday, August 21,...

  11. 33 CFR 117.353 - Atlantic Intracoastal Waterway, Savannah River to St. Marys River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Savannah River to St. Marys River. 117.353 Section 117.353 Navigation and Navigable Waters COAST GUARD....353 Atlantic Intracoastal Waterway, Savannah River to St. Marys River. (a) General. Public vessels of... Bridge, SR 204, mile 592.9 near Savannah. The draw will open as necessary on the hour from 7 a.m. to 9...

  12. 33 CFR 117.911 - Atlantic Intracoastal Waterway, Little River to Savannah River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Atlantic Intracoastal Waterway, Little River to Savannah River. 117.911 Section 117.911 Navigation and Navigable Waters COAST GUARD... § 117.911 Atlantic Intracoastal Waterway, Little River to Savannah River. (a) General. Public vessels...

  13. 33 CFR 100.732 - Annual River Race Augusta; Savannah River, Augusta GA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...; Savannah River, Augusta GA. 100.732 Section 100.732 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... River Race Augusta; Savannah River, Augusta GA. (a) Definitions: (1) Regulated Area. The regulated area is formed by a line drawn directly across the Savannah River at the U.S. Highway 1 Bridge at...

  14. 33 CFR 117.353 - Atlantic Intracoastal Waterway, Savannah River to St. Marys River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., Savannah River to St. Marys River. 117.353 Section 117.353 Navigation and Navigable Waters COAST GUARD....353 Atlantic Intracoastal Waterway, Savannah River to St. Marys River. (a) General. Public vessels of... Bridge, SR 204, mile 592.9 near Savannah. The draw will open as necessary on the hour from 7 a.m. to 9...

  15. 33 CFR 100.732 - Annual River Race Augusta; Savannah River, Augusta GA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...; Savannah River, Augusta GA. 100.732 Section 100.732 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... River Race Augusta; Savannah River, Augusta GA. (a) Definitions: (1) Regulated Area. The regulated area is formed by a line drawn directly across the Savannah River at the U.S. Highway 1 Bridge at...

  16. 33 CFR 100.732 - Annual River Race Augusta; Savannah River, Augusta GA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...; Savannah River, Augusta GA. 100.732 Section 100.732 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... River Race Augusta; Savannah River, Augusta GA. (a) Definitions: (1) Regulated Area. The regulated area is formed by a line drawn directly across the Savannah River at the U.S. Highway 1 Bridge at...

  17. 33 CFR 100.732 - Annual River Race Augusta; Savannah River, Augusta GA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...; Savannah River, Augusta GA. 100.732 Section 100.732 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... River Race Augusta; Savannah River, Augusta GA. (a) Definitions: (1) Regulated Area. The regulated area is formed by a line drawn directly across the Savannah River at the U.S. Highway 1 Bridge at...

  18. 33 CFR 117.353 - Atlantic Intracoastal Waterway, Savannah River to St. Marys River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., Savannah River to St. Marys River. 117.353 Section 117.353 Navigation and Navigable Waters COAST GUARD....353 Atlantic Intracoastal Waterway, Savannah River to St. Marys River. (a) General. Public vessels of... Bridge, SR 204, mile 592.9 near Savannah. The draw will open as necessary on the hour from 7 a.m. to 9...

  19. 33 CFR 100.732 - Annual River Race Augusta; Savannah River, Augusta GA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...; Savannah River, Augusta GA. 100.732 Section 100.732 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... River Race Augusta; Savannah River, Augusta GA. (a) Definitions: (1) Regulated Area. The regulated area is formed by a line drawn directly across the Savannah River at the U.S. Highway 1 Bridge at...

  20. 33 CFR 117.353 - Atlantic Intracoastal Waterway, Savannah River to St. Marys River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Savannah River to St. Marys River. 117.353 Section 117.353 Navigation and Navigable Waters COAST GUARD....353 Atlantic Intracoastal Waterway, Savannah River to St. Marys River. (a) General. Public vessels of... Bridge, SR 204, mile 592.9 near Savannah. The draw will open as necessary on the hour from 7 a.m. to 9...

  1. 33 CFR 117.353 - Atlantic Intracoastal Waterway, Savannah River to St. Marys River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., Savannah River to St. Marys River. 117.353 Section 117.353 Navigation and Navigable Waters COAST GUARD....353 Atlantic Intracoastal Waterway, Savannah River to St. Marys River. (a) General. Public vessels of... Bridge, SR 204, mile 592.9 near Savannah. The draw will open as necessary on the hour from 7 a.m. to 9...

  2. 33 CFR 117.911 - Atlantic Intracoastal Waterway, Little River to Savannah River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Atlantic Intracoastal Waterway, Little River to Savannah River. 117.911 Section 117.911 Navigation and Navigable Waters COAST GUARD... § 117.911 Atlantic Intracoastal Waterway, Little River to Savannah River. (a) General. Public vessels...

  3. 78 FR 22423 - Drawbridge Operation Regulations; Taunton River, Fall River and Somerset, MA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-16

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 117 Drawbridge Operation Regulations; Taunton River, Fall River and... Brightman Street Bridge across the Taunton River, mile 1.8, between Fall River and Somerset,...

  4. 75 FR 32351 - Drawbridge Operation Regulation; Taunton River, Fall River and Somerset, MA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-08

    ... SECURITY Coast Guard 33 CFR Part 117 RIN 1625-AA09 Drawbridge Operation Regulation; Taunton River, Fall...) Bridge at mile 1.8, between Fall River and Somerset, Massachusetts, to help relieve the bridge owner from... Taunton River between Fall River and Somerset, Massachusetts, has a vertical clearance in the...

  5. 78 FR 31457 - Drawbridge Operation Regulation; Taunton River, Fall River and Somerset, MA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-24

    .... USCG-2013-0291] RIN 1625-AA09 Drawbridge Operation Regulation; Taunton River, Fall River and Somerset..., mile 2.1, between Fall River and Somerset, Massachusetts. The bridge owner, Massachusetts Department of... between Somerset and Fall River, Massachusetts, has a vertical clearance of 60 feet at mean high water...

  6. ALWAYS A RIVER - SUPPLEMENTAL ENVIRONMENTAL EDUCATION CURRICULUM ON THE OHIO RIVER AND WATER GRADES K - 12

    EPA Science Inventory

    This curriculum was developed as a significant component of the project, Always a River: The Ohio River and the American Experience, a six-state collaboration devoted to exploring the historical and cultural development of the Ohio River. The Always a River project is being joint...

  7. Aerial view of the entire bridge crossing the Tennessee River ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Aerial view of the entire bridge crossing the Tennessee River looking up river. The swing bridge, when open, permits river navigational traffic to ply the river. Construction of a replacement bridge, to be located 93.27 feet down river, has now started. - Bridgeport Swing Span Bridge, Spanning Tennessee River, Bridgeport, Jackson County, AL

  8. 4. ENVIRONMENT, FROM NORTH, SHOWING RIVER ROAD BRIDGE CARRYING CASSELMAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. ENVIRONMENT, FROM NORTH, SHOWING RIVER ROAD BRIDGE CARRYING CASSELMAN RIVER ROAD OVER CASSELMAN RIVER, WITH MARYLAND GEOLOGICAL SURVEY STREAM-GAUGING STATION AT NORTHEAST CORNER OF BRIDGE - River Road Bridge, Crossing Casselman River on Casselman River Road, Grantsville, Garrett County, MD

  9. Advances in river ice hydrology

    NASA Astrophysics Data System (ADS)

    Beltaos, Spyros

    2000-06-01

    River ice is present in nearly all Canadian rivers, for periods ranging from days to many months. Whether moving or stationary, it interacts with the river flow in various ways, resulting in multiple impacts on the economy and ecosystem, and posing a major flood threat to riverside communities. In the past 4 years, Canadian research and development efforts have been directed at a variety of problems. A strong focus on ice breakup and ice jam processes resulted in improved understanding of the salient geomorphological and hydroclimatic factors, enhanced modelling and prediction capabilities, and development of techniques for in situ measurement of ice jam properties. Key contributions in the area of ecological impacts of river ice and ice jams have led not only to solid advances in knowledge, but also to an appreciation of the vast scope of this subject and its numerous links to environmental science. A closely related topic, the flux of suspended sediment in ice-laden rivers was studied for the first time, in order to delineate the effects of the ice on sediment and associated contaminant loads. In response to growing concern about climate change and variability, several studies addressed implications to ice regime, and thence, to ecology and economy. Although not fully explored, the potential impacts appear to be numerous and significant, owing to the high sensitivity of river ice processes to climatic factors. In the foreseeable future, research is likely to continue along the above noted lines, although an increased emphasis on climatic and ecological aspects is probable. Insights gained on the mechanisms of breakup and jamming may lead to increased modelling applications and testing of theoretical concepts.

  10. River Sinuosity Classification - The method

    NASA Astrophysics Data System (ADS)

    Petrovszki, J.; Székely, B.; Timár, G.

    2012-04-01

    We introduced a new evaluation method, the classification of multiple window-size based sinuosity spectrum. If the river is long enough for the analysis, the classification could be as useful, as the sinuosity spectrum, but sometimes it is more straightforward. Furthermore, for the classification, we did not need the main parameters of the river, e.g. the bankfull discharge. Each sinuosity calculation that was performed for a given window size, has been considered as one band (one channel) of a multichannel "image". Then, the sinuosity spectrums became multichannel images are of size 1 X N where N represents the length of the actual river in pixels. Using this multichannel input unsupervised ISOCLASS classification was carried out on these data, using ER Mapper software. The requested number of classes was set to 5. The results of the sinuosity calculations are scalars. Earlier, it was a subjective decision to divide the sinuosity values into the categories (low, medium-low, medium, medium-high, and high), while the new method provides integer numbers (1 to 5) itself. These numbers are calculated from the sinuosity values, but are not equal to them. Analysing the results of the classification, it is important to note that the method typically splits the river course into contiguous sections that belong to the same class. Boundaries of these classes can be considered as points of considerable change in the river course, because the method uses statistically relevant amount of data of the river course in a robust way to detect changes. Some specific classes or their boundaries seem to be correlated to tectonically active zones. The research is made in the frame of project OTKA-NK83400 (SourceSink Hungary). The European Union and the European Social Fund also have provided financial support to the project under the grant agreement no. TÁMOP 4.2.1./B-09/1/KMR-2010-0003.

  11. Nile River, Lake Nasser, Aswan Dam, Egypt

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Egypt's High Aswan Dam on the Nile River at the first cataracts, Nile River, (24.0N, 33.0E) was completed in 1971 to provide cheap hydroelectric power and to regulate the historically uneven flow of the Nile River. The contrast between the largely base rock desert east of the Nile versus the sand covered desert west of the river and the ancient irrigated floodplain downstream from the damsite is clearly shown.

  12. Columbia River Component Data Evaluation Summary Report

    SciTech Connect

    C.S. Cearlock

    2006-08-02

    The purpose of the Columbia River Component Data Compilation and Evaluation task was to compile, review, and evaluate existing information for constituents that may have been released to the Columbia River due to Hanford Site operations. Through this effort an extensive compilation of information pertaining to Hanford Site-related contaminants released to the Columbia River has been completed for almost 965 km of the river.

  13. American River Watershed Investigation, California. Reconnaisance Report

    DTIC Science & Technology

    1988-01-01

    River, and sometimes from the American River via the Sacramento Weir. When the combined flow of the Sacramento and Feather Rivers and the Sutter Bypass...goods and services in the American River watershed will continue as currently projected. The population growth rate in the City of Sacramento and...Sacramento, El Dorado, and Placer Counties is projected to exceed the growth rate for the State of California through the year 2020. lable 6 shows the

  14. Floods in the Raccoon River basin, Iowa

    USGS Publications Warehouse

    Heinitz, Albert J.

    1980-01-01

    Evaluation of flood hazards, and the planning, design, and operation of various facilities on flood plains requires information on floods. This report provides information on flood stages and discharges, flood magnitude and frequency, bench mark data, and flood profiles for the Raccoon River and some of its tributaries. Ir covers the Raccoon River, the North Raccoon River to the northern boundary of Sac County and the lower reaches of the Middle and South Raccoon Rivers.

  15. Polarimetric Backscattering Behavior of River Ice Cover

    NASA Astrophysics Data System (ADS)

    Mermoz, S.; Gherboudj, I.; Allain, S.; Bernier, M.; Pottier, E.

    2009-04-01

    In many northern rivers of Canada, the formation of the ice covers leads to important situations: ice jamming, and then flooding of large areas. Thus, the monitoring of river ice is necessary. Gherboudj has developed a model in order to understand the interactions of the radar signal with the river ice cover. The model is improved to simulate the fully polarimetric response of a river ice cover. The aim of this work is to analyse the results of the simulations.

  16. Columbia River Impact Evaluation Plan

    SciTech Connect

    Weiss, S.G.

    1994-03-01

    A preliminary impact evaluation was conducted to assess the adequacy of existing data and proposed data collection programs for evaluating cumulative health and environmental impacts to the Columbia River due to past practices at the Hanford Site. The results of this evaluation were used to develop this plan to ensure collection of sufficient data for adequate characterization of the Columbia River along the 100 Area for CERCLA purposes. The evaluation used to develop the plan is not a risk assessment; the plan presented here is only a mechanism to collect additional data to support a future risk assessment.

  17. Mighty Microbes Where Rivers Run

    SciTech Connect

    Stegen, James

    2016-04-07

    Microbes and their influential role in Earth’s climate take center stage in the area where river water and groundwater mix – an area known as the hyporheic zone. PNNL ecologist James Stegen discusses his team’s research in his “laboratory” – the zone along the Columbia, one of the nation’s largest rivers. It’s a squishy, porous lab, better known for soaking feet than serving as the “river’s liver.” Read more: http://www.pnl.gov/news/release.aspx?...

  18. River enhancement in the Upper Mississippi River basin: Approaches based on river uses, alterations, and management agencies

    USGS Publications Warehouse

    O'Donnell, T. K.; Galat, D.L.

    2007-01-01

    The Upper Mississippi River is characterized by a series of locks and dams, shallow impoundments, and thousands of river channelization structures that facilitate commercial navigation between Minneapolis, Minnesota, and Cairo, Illinois. Agriculture and urban development over the past 200 years have degraded water quality and increased the rate of sediment and nutrient delivery to surface waters. River enhancement has become an important management tool employed to address causes and effects of surface water degradation and river modification in the Upper Mississippi River Basin. We report information on individual river enhancement projects and contrast project densities, goals, activities, monitoring, and cost between commercially non-navigated and navigated rivers (Non-navigated and Navigated Rivers, respectively). The total number of river enhancement projects collected during this effort was 62,108. Cost of all projects reporting spending between 1972 and 2006 was about US$1.6 billion. Water quality management was the most cited project goal within the basin. Other important goals in Navigated Rivers included in-stream habitat improvement and flow modification. Most projects collected for Non-navigated Rivers and their watersheds originated from the U.S. Department of Agriculture (USDA). The U.S. Army Corps of Engineers and the USDA were important sources for projects in Navigated Rivers. Collaborative efforts between agencies that implement projects in Non-navigated and Navigated Rivers may be needed to more effectively address river impairment. However, the current state of data sources tracking river enhancement projects deters efficient and broad-scale integration. ?? Journal compilation ?? 2007 Society for Ecological Restoration International.

  19. Home on the Big River: Great River Habitat Quality Indices

    EPA Science Inventory

    EPA’s Environmental Monitoring and Assessment Program sampled the Upper Mississippi, Missouri and Ohio Rivers from 2004 through 2006 as part of an integrated assessment of ecological condition. We developed fish habitat indices by dividing the components of habitat into four ca...

  20. Red River of the North Reconnaissance Report: Ottertail River Subbasin.

    DTIC Science & Technology

    1980-12-01

    32 8 Possible Sediment and Nutrient Source Types in the Ottertail River Subbasin ...... .................. ... 34 9 Groundwater ... groundwater quality, high iron and manganese concentrations have bea reported in certain areas (Minnesota Pollution Control Agency, 1975; Minnesota Water...contains 1.5 million acre feet of water in storage; however, only a relatively small amount is economically recoverable. Some groundwater supplies are

  1. Red River of the North Reconnaissance Report: Buffalo River Subbasin.

    DTIC Science & Technology

    1980-12-01

    October 1977 and April 1978 .... .............. . . . 35 10 Groundwater Quality Data from Comuunities in the Buffalo River Subbasin...weed and insect control. Groundwater quality problems are related to high concentrations of iron and manganese, dissolved solids, and sulfate (Upper...unable to meet water supply needs g(because of inadequate storage potentials). Communities in the subbasin 14 use groundwater for all municipal needs

  2. River flow regimes and vegetation dynamics along a river transect

    NASA Astrophysics Data System (ADS)

    Doulatyari, Behnam; Basso, Stefano; Schirmer, Mario; Botter, Gianluca

    2014-11-01

    Ecohydrological processes occurring within fluvial landscapes are strongly affected by natural streamflow variability. In this work the patterns of vegetation biomass in two rivers characterized by contrasting flow regimes were investigated by means of a comprehensive stochastic model which explicitly couples catchment-scale hydroclimatic processes, morphologic attributes of the river transect and in-stream bio-ecological features. The hydrologic forcing is characterized by the probability distribution (pdf) of streamflows and stages resulting from stochastic precipitation dynamics, rainfall-runoff transformation and reach scale morphologic attributes. The model proved able to reproduce the observed pdf of river flows and stages, as well as the pattern of exposure/inundation along the river transect in both regimes. Our results suggest that in persistent regimes characterized by reduced streamflow variability, mean vegetation biomass is chiefly controlled by the pattern of groundwater availability along the transect, leading to a marked transition between aquatic and terrestrial environments. Conversely, erratic regimes ensure wider aquatic-terrestrial zones in which optimal elevation ranges for species with different sensitivity to flooding and access to groundwater are separated. Patterns of mean biomass in erratic regimes were found to be more sensitive to changes in the underlying hydroclimatic conditions, notwithstanding the reduced responsiveness of the corresponding flow regimes. The framework developed highlights the important role played by streamflow regimes in shaping riverine environments, and may eventually contribute to identifying the influence of landscape, climate and morphologic features on in-stream ecological dynamics.

  3. Rivers Run Through It: Discovering the Interior Columbia River Basin.

    ERIC Educational Resources Information Center

    Davis, Shelley; Wojtanik, Brenda Lincoln; Rieben, Elizabeth

    1998-01-01

    Explores the Columbia River Basin, its ecosystems, and challenges faced by natural resource managers. By studying the basin's complexity, students can learn about common scientific concepts such as the power of water and effects of rain shadows. Students can also explore social-scientific issues such as conflicts between protecting salmon runs and…

  4. 33 CFR 117.391 - Chicago River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Chicago River. 117.391 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Illinois § 117.391 Chicago River. The draws of the bridges operated by the City of Chicago over the Main Branch of Chicago River, the bridges on the...

  5. River as a part of ground battlefield

    NASA Astrophysics Data System (ADS)

    Vračar, Miodrag S.; Pokrajac, Ivan; Okiljević, Predrag

    2013-05-01

    The rivers are in some circumstances part of the ground battlefield. Microseisms induced at the riverbed or ground at the river surrounding might be consequence of military activities (military ground transports, explosions, troop's activities, etc). Vibrations of those fluid-solid structures are modeled in terms of solid displacement and change of fluid pressure. This time varying fluid pressure in river, which originates from ground microseisms, is possible to detect with hydrophones. Therefore, hydroacoustic measurements in rivers enables detecting, identification and localization various types of military noisy activities at the ground as and those, which origin is in the river water (hydrodynamics of water flow, wind, waves, river vessels, etc). In this paper are presented river ambient noise measurements of the three great rivers: the Danube, the Sava and the Tisa, which flows in north part of Serbia in purpose to establish limits in detection of the ground vibrations in relatively wide frequency range from zero to 20 kHz. To confirm statement that the river is a part of ground battlefield, and that hydroacoustic noise is possible to use in detecting and analyzing ground microseisms induced by civil or military activities, some previous collected data of hydroacoustic noise measurement in the rivers are used. The data of the river ambient noise include noise induced by civil engineering activities, that ordinary take place in large cities, noise that produced ships and ambient noise of the river when human activities are significantly reduced. The poly spectral method was used in analysis such events.

  6. 33 CFR 117.570 - Sassafras River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Sassafras River. 117.570 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.570 Sassafras River. The draw of the Sassafras River (Route 213) bridge, mile 10.0 at Georgetown, Maryland, shall open on signal; except...

  7. 33 CFR 117.570 - Sassafras River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Sassafras River. 117.570 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.570 Sassafras River. The draw of the Sassafras River (Route 213) bridge, mile 10.0 at Georgetown, Maryland, shall open on signal; except...

  8. 33 CFR 117.570 - Sassafras River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Sassafras River. 117.570 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.570 Sassafras River. The draw of the Sassafras River (Route 213) bridge, mile 10.0 at Georgetown, Maryland, shall open on signal; except...

  9. 33 CFR 117.570 - Sassafras River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Sassafras River. 117.570 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.570 Sassafras River. The draw of the Sassafras River (Route 213) bridge, mile 10.0 at Georgetown, Maryland, shall open on signal; except...

  10. 33 CFR 117.570 - Sassafras River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Sassafras River. 117.570 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.570 Sassafras River. The draw of the Sassafras River (Route 213) bridge, mile 10.0 at Georgetown, Maryland, shall open on signal; except...

  11. 33 CFR 117.300 - Manatee River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Manatee River. 117.300 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.300 Manatee River. The draw of the CSX Railroad Bridge across the Manatee River, mile 4.5 Bradenton, operates as follows: (a) The bridge is...

  12. 33 CFR 117.189 - Sacramento River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Sacramento River. 117.189 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.189 Sacramento River. (a) The draws of each bridge from Isleton to American River junction shall open on signal from May 1...

  13. 33 CFR 117.391 - Chicago River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Chicago River. 117.391 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Illinois § 117.391 Chicago River. The draws of the bridges operated by the City of Chicago over the Main Branch of Chicago River, the bridges on the...

  14. 33 CFR 117.118 - Tombigbee River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Tombigbee River. 117.118 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Alabama § 117.118 Tombigbee River. The draw of the Meridian and Bigbee Railroad (MNBR) vertical lift span bridge across the Tombigbee River, mile 128.6...

  15. 46 CFR 90.10-33 - Rivers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Rivers. 90.10-33 Section 90.10-33 Shipping COAST GUARD... Terms Used in This Subchapter § 90.10-33 Rivers. Under this designation shall be included all vessels whose navigation is restricted to rivers and/or canals exclusively, and to such other waters as may...

  16. 33 CFR 117.397 - Wabash River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Wabash River. 117.397 Section 117... OPERATION REGULATIONS Specific Requirements Illinois § 117.397 Wabash River. The draws of the bridges across the Wabash River need not be opened for the passage of vessels. Indiana...

  17. 33 CFR 117.424 - Belle River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Belle River. 117.424 Section 117... OPERATION REGULATIONS Specific Requirements Louisiana § 117.424 Belle River. The draw of the S70 bridge, mile 23.8 (Landside Route) near Belle River, shall open on signal; except that, from 10 p.m. to 6...

  18. 33 CFR 117.337 - Trout River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Trout River. 117.337 Section 117... OPERATION REGULATIONS Specific Requirements Florida § 117.337 Trout River. The draw of the CSX Railroad Bridge across the Trout River, mile 0.9 at Jacksonville, operates as follows: (a) The bridge is...

  19. 46 CFR 151.03-45 - Rivers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Rivers. 151.03-45 Section 151.03-45 Shipping COAST GUARD... HAZARDOUS MATERIAL CARGOES Definitions § 151.03-45 Rivers. A designation for all vessels whose navigation is restricted to rivers and/or canals, exclusively....

  20. 33 CFR 117.424 - Belle River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Belle River. 117.424 Section 117... OPERATION REGULATIONS Specific Requirements Louisiana § 117.424 Belle River. The draw of the S70 bridge, mile 23.8 (Landside Route) near Belle River, shall open on signal; except that, from 10 p.m. to 6...

  1. 33 CFR 117.411 - Missouri River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Missouri River. 117.411 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Kansas § 117.411 Missouri River. The draws of the bridges across the Missouri River shall open on signal; except during the winter season between the...

  2. 33 CFR 117.411 - Missouri River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Missouri River. 117.411 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Kansas § 117.411 Missouri River. The draws of the bridges across the Missouri River shall open on signal; except during the winter season between the...

  3. 33 CFR 117.359 - Chattahoochee River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Chattahoochee River. 117.359... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Georgia § 117.359 Chattahoochee River. See § 117.107, Chattahoochee River, listed under Alabama....

  4. 33 CFR 117.183 - Old River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Old River. 117.183 Section 117... OPERATION REGULATIONS Specific Requirements California § 117.183 Old River. The draw of the California... notice is given to the drawtender at the Rio Vista bridge across the Sacramento River, mile 12.8....

  5. 33 CFR 117.175 - Mokelumne River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Mokelumne River. 117.175 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.175 Mokelumne River. (a) The draw of the California Department of Transportation highway bridge, the Mokelumne River Bridge, mile 3.0,...

  6. 33 CFR 117.175 - Mokelumne River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Mokelumne River. 117.175 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.175 Mokelumne River. (a) The draw of the California Department of Transportation highway bridge, the Mokelumne River Bridge, mile 3.0,...

  7. 33 CFR 117.258 - Apalachicola River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Apalachicola River. 117.258... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.258 Apalachicola River. The draw of the CSX Railroad bridge, mile 105.9, at River Junction shall open on signal Monday through Friday from 8...

  8. 33 CFR 117.359 - Chattahoochee River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Chattahoochee River. 117.359... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Georgia § 117.359 Chattahoochee River. See § 117.107, Chattahoochee River, listed under Alabama....

  9. 46 CFR 90.10-33 - Rivers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Rivers. 90.10-33 Section 90.10-33 Shipping COAST GUARD... Terms Used in This Subchapter § 90.10-33 Rivers. Under this designation shall be included all vessels whose navigation is restricted to rivers and/or canals exclusively, and to such other waters as may...

  10. 33 CFR 117.407 - Missouri River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Missouri River. 117.407 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Iowa § 117.407 Missouri River. See § 117.691, Missouri River listed under Nebraska. Kansas...

  11. 33 CFR 117.189 - Sacramento River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Sacramento River. 117.189 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.189 Sacramento River. (a) The draws of each bridge from Isleton to the American River junction except for the Sacramento County...

  12. 46 CFR 188.10-61 - Rivers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Rivers. 188.10-61 Section 188.10-61 Shipping COAST GUARD... Terms Used in This Subchapter § 188.10-61 Rivers. Under this designation shall be included all vessels whose navigation is restricted to rivers and/or canals exclusively, and to such other waters as may...

  13. 33 CFR 117.299 - Loxahatchee River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Loxahatchee River. 117.299... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.299 Loxahatchee River. The draw of the Florida East Coast Railway bridge across the Loxahatchee River, mile 1.2 at Jupiter, operates as...

  14. 33 CFR 117.337 - Trout River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Trout River. 117.337 Section 117... OPERATION REGULATIONS Specific Requirements Florida § 117.337 Trout River. The draw of the CSX Railroad Bridge across the Trout River, mile 0.9 at Jacksonville, operates as follows: (a) The bridge is...

  15. 33 CFR 117.258 - Apalachicola River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Apalachicola River. 117.258... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.258 Apalachicola River. (a) The draw of..., mile 105.9, at River Junction shall open on signal if at least eight hours notice is given....

  16. 33 CFR 117.527 - Kennebunk River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Kennebunk River. 117.527 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maine § 117.527 Kennebunk River. The Dock Square drawbridge at mile 1.0, across the Kennebunk River, between Kennebunk and Kennebunkport, Maine, need not...

  17. 33 CFR 117.527 - Kennebunk River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Kennebunk River. 117.527 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maine § 117.527 Kennebunk River. The Dock Square drawbridge at mile 1.0, across the Kennebunk River, between Kennebunk and Kennebunkport, Maine, need not...

  18. 33 CFR 117.397 - Wabash River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Wabash River. 117.397 Section 117... OPERATION REGULATIONS Specific Requirements Illinois § 117.397 Wabash River. The draws of the bridges across the Wabash River need not be opened for the passage of vessels. Indiana...

  19. 33 CFR 117.424 - Belle River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Belle River. 117.424 Section 117... OPERATION REGULATIONS Specific Requirements Louisiana § 117.424 Belle River. The draw of the S70 bridge, mile 23.8 (Landside Route) near Belle River, shall open on signal; except that, from 10 p.m. to 6...

  20. 33 CFR 117.424 - Belle River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Belle River. 117.424 Section 117... OPERATION REGULATIONS Specific Requirements Louisiana § 117.424 Belle River. The draw of the S70 bridge, mile 23.8 (Landside Route) near Belle River, shall open on signal; except that, from 10 p.m. to 6...

  1. 33 CFR 117.299 - Loxahatchee River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Loxahatchee River. 117.299... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.299 Loxahatchee River. The draw of the Florida East Coast Railway bridge across the Loxahatchee River, mile 1.2 at Jupiter, operates as...

  2. 33 CFR 117.337 - Trout River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Trout River. 117.337 Section 117... OPERATION REGULATIONS Specific Requirements Florida § 117.337 Trout River. The draw of the CSX Railroad Bridge across the Trout River, mile 0.9 at Jacksonville, operates as follows: (a) The bridge is...

  3. 46 CFR 188.10-61 - Rivers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Rivers. 188.10-61 Section 188.10-61 Shipping COAST GUARD... Terms Used in This Subchapter § 188.10-61 Rivers. Under this designation shall be included all vessels whose navigation is restricted to rivers and/or canals exclusively, and to such other waters as may...

  4. 33 CFR 117.411 - Missouri River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Missouri River. 117.411 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Kansas § 117.411 Missouri River. The draws of the bridges across the Missouri River shall open on signal; except during the winter season between the...

  5. 33 CFR 117.300 - Manatee River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Manatee River. 117.300 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.300 Manatee River. The draw of the CSX Railroad Bridge across the Manatee River, mile 4.5 Bradenton, operates as follows: (a) The bridge is...

  6. 33 CFR 117.359 - Chattahoochee River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Chattahoochee River. 117.359... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Georgia § 117.359 Chattahoochee River. See § 117.107, Chattahoochee River, listed under Alabama....

  7. 33 CFR 117.118 - Tombigbee River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Tombigbee River. 117.118 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Alabama § 117.118 Tombigbee River. The draw of the Meridian and Bigbee Railroad (MNBR) vertical lift span bridge across the Tombigbee River, mile 128.6...

  8. 33 CFR 117.397 - Wabash River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Wabash River. 117.397 Section 117... OPERATION REGULATIONS Specific Requirements Illinois § 117.397 Wabash River. The draws of the bridges across the Wabash River need not be opened for the passage of vessels. Indiana...

  9. 33 CFR 117.189 - Sacramento River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Sacramento River. 117.189 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.189 Sacramento River. (a) The draws of each bridge from Isleton to American River junction shall open on signal from May 1...

  10. 33 CFR 117.527 - Kennebunk River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Kennebunk River. 117.527 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maine § 117.527 Kennebunk River. The Dock Square drawbridge at mile 1.0, across the Kennebunk River, between Kennebunk and Kennebunkport, Maine, need not...

  11. 46 CFR 90.10-33 - Rivers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Rivers. 90.10-33 Section 90.10-33 Shipping COAST GUARD... Terms Used in This Subchapter § 90.10-33 Rivers. Under this designation shall be included all vessels whose navigation is restricted to rivers and/or canals exclusively, and to such other waters as may...

  12. 33 CFR 117.527 - Kennebunk River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Kennebunk River. 117.527 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maine § 117.527 Kennebunk River. The Dock Square drawbridge at mile 1.0, across the Kennebunk River, between Kennebunk and Kennebunkport, Maine, need not...

  13. 33 CFR 117.547 - Bush River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bush River. 117.547 Section 117... OPERATION REGULATIONS Specific Requirements Maryland § 117.547 Bush River. The draw of the Amtrak bridge... Superintendent at 301-291-4278 by an authorized representative of the Bush River Yacht Club by noon on the...

  14. 46 CFR 151.03-45 - Rivers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Rivers. 151.03-45 Section 151.03-45 Shipping COAST GUARD... HAZARDOUS MATERIAL CARGOES Definitions § 151.03-45 Rivers. A designation for all vessels whose navigation is restricted to rivers and/or canals, exclusively....

  15. 33 CFR 117.299 - Loxahatchee River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Loxahatchee River. 117.299... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.299 Loxahatchee River. The draw of the Florida East Coast Railway bridge across the Loxahatchee River, mile 1.2 at Jupiter, operates as...

  16. 33 CFR 117.175 - Mokelumne River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Mokelumne River. 117.175 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.175 Mokelumne River. (a) The draw of the California Department of Transportation highway bridge, the Mokelumne River Bridge, mile 3.0,...

  17. 33 CFR 117.359 - Chattahoochee River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Chattahoochee River. 117.359... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Georgia § 117.359 Chattahoochee River. See § 117.107, Chattahoochee River, listed under Alabama....

  18. 33 CFR 117.299 - Loxahatchee River.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Loxahatchee River. 117.299... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.299 Loxahatchee River. The draw of the Florida East Coast Railway bridge across the Loxahatchee River, mile 1.2 at Jupiter, operates as...

  19. 33 CFR 117.258 - Apalachicola River.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Apalachicola River. 117.258... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.258 Apalachicola River. (a) The draw of..., mile 105.9, at River Junction shall open on signal if at least eight hours notice is given....

  20. 33 CFR 117.397 - Wabash River.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Wabash River. 117.397 Section 117... OPERATION REGULATIONS Specific Requirements Illinois § 117.397 Wabash River. The draws of the bridges across the Wabash River need not be opened for the passage of vessels. Indiana...