WorldWideScience

Sample records for sand wave shoaling

  1. Sand Waves. Report 1. Sand Wave Shoaling in Navigation Channels

    Science.gov (United States)

    1992-09-01

    heights range from 0.8 m in the Minas Basin, Bay of Fundy (Dalrymple 1984) to 6.0 m in the Bahia Blanca Estuary, Argentina (Aliotta and Perillo 1987...26 PART IV: SITE-SPECIFIC SAND WAVE SHOALING PROBLEMS .. ........ 30 Columbia River Navigation Channel ........ ............... .. 30 Panama ...problem location discussed in this report is at St. Andrew Bay near Panama City, Florida. A relatively short section of the jettied inlet channel requires

  2. Kinematic criterion for breaking of shoaling waves

    Science.gov (United States)

    Liberzon, Dan; Itay, Uri

    2016-11-01

    Validity of a kinematic criterion for breaking of shoaling waves was examined experimentally. Results obtained by simultaneous measurements of water surface velocity by PTV and of the propagation velocity of a steep crest up to the point of breaking inception during shoaling will be reported. The experiments performed in a large wave tank examining breaking behavior of gentle spillers during shoaling on three different slopes suggest a validity of the recently proposed kinematic criterion. The breaking inception was found to occur when the horizontal velocity of the water surface on the steep (local steepness of 0.41-0.6) crest reaches a threshold value of 0.85-0.95 of that of the crest propagation. The exact moment and position of breaking inception detected using a Phase Time Method (PTM), characterizing a unique shape of the local frequency fluctuations at the inception. Future implementation of the PTM method for detection of breaking events in irregular wave fields will be discussed. Supported by German-Israeli Foundation for Scientific Research and Development (GIF) Grant #2019392.

  3. Shear stresses and mean flow in shoaling and breaking waves

    NARCIS (Netherlands)

    Stive, M.J.F.; De Vriend, H.J.

    1994-01-01

    We investigate the vertical, wave averaged distributions of shear stresses and Eulerian flow in normally incident, shoaling and breaking waves. It is found that shear stresses are solely due to wave amplitude variations, which can be caused by shoaling, boundary layer dissipation and/or breaking wav

  4. Shoaling Large Amplitude Internal Solitary Waves in a Laboratory Tank

    Science.gov (United States)

    Allshouse, Michael; Larue, Conner; Swinney, Harry

    2014-11-01

    The shoaling of internal solitary waves onto the continental shelf can change both the wave dynamics and the state of the environment. Previous observations have demonstrated that these waves can trap fluid and transport it over long distances. Through the use of a camshaft-based wavemaker, we produce large amplitude shoaling waves in a stratified fluid in a laboratory tank. Simulations of solitary waves are used to guide the tuning of the wave generator to approximate solitary waves; thus nonlinear waves can be produced within the 4m long tank. PIV and synthetic schlieren measurements are made to study the transport of fluid by the wave as it moves up a sloping boundary. The results are then compared to numerical simulations and analyzed using finite time Lyapunov exponent calculations. This Lagrangian analysis provides an objective measure of barriers surrounding trapped regions in the flow. Supported by ONR MURI Grant N000141110701 (WHOI).

  5. Numerical simulations of shoaling internal solitary waves of elevation

    Science.gov (United States)

    Xu, Chengzhu; Subich, Christopher; Stastna, Marek

    2016-07-01

    We present high-resolution, two- and three-dimensional direct numerical simulations of large amplitude internal solitary waves of elevation on the laboratory scale, shoaling onto and over a small-amplitude shelf. The three-dimensional, mapped coordinate, spectral collocation method used for the simulations allows for accurate modelling of both the shoaling waves and the bottom boundary layer. The shoaling of the waves is characterized by the formation of a quasi-trapped core which undergoes a spatially growing stratified shear instability at its edge and a lobe-cleft instability in its nose. Both of these instabilities develop and three-dimensionalize concurrently, leading to strong bottom shear stress. We explore significant regions of Schmidt and Reynolds number space and demonstrate that the formation of shear instabilities during shoaling is robust and should be readily observable in a number of standard laboratory setups. In the experiments with a corrugated bottom boundary, boundary layer separation is found inside each of the corrugations during shoaling. This more complex boundary layer phenomenology precludes the formation of the lobe-cleft instability almost completely and hence provides a different mechanism for fluid and material exchange across the bottom boundary layer. Our analyses suggest that all of these wave-induced instabilities can lead to enhanced turbulence in the water column and increased shear stress on the bottom boundary. Through the generation and evolution of these instabilities, the shoaling of internal solitary waves of elevation is likely to provide systematic mechanisms for material mixing, cross-boundary layer transport, and sediment resuspension.

  6. Solitary wave shoaling and breaking in a regularized Boussinesq system

    CERN Document Server

    Senthilkumar, Amutha

    2016-01-01

    A coupled BBM system of equations is studied in the situation of water waves propagating over decreasing fluid depth. A conservation equation for mass and a wave breaking criterion valid in the Boussinesq approximation is found. A Fourier collocation method coupled with a 4-stage Runge-Kutta time integration scheme is employed to approximate solutions of the BBM system. The mass conservation equation is used to quantify the role of reflection in the shoaling of solitary waves on a sloping bottom. Shoaling results based on an adiabatic approximation are analyzed. Wave shoaling and the criterion of breaking solitary waves on a sloping bottom is studied. To validate the numerical model the simulation results are compared with those obtained by Grilli et al.[16] and a good agreement between them is observed. Shoaling of solitary waves of two different types of mild slope model systems in [8] and [13] are compared, and it is found that each of these models works well in their respective regimes of applicability.

  7. Shoaling and shoreline dissipation of low‐frequency waves

    NARCIS (Netherlands)

    Van Dongeren, A.; Battjes, J.A.; Janssen, T.; Van Noorloos, J.; Steenhauer, K.; Steenbergen, G.; Reniers, A.

    2007-01-01

    The growth rate, shoreline reflection, and dissipation of low‐frequency waves are investigated using data obtained from physical experiments in the Delft University of Technology research flume and by parameter variation using the numerical model Delft3D‐SurfBeat. The growth rate of the shoaling inc

  8. A sand wave simulation model

    NARCIS (Netherlands)

    Nemeth, A.A.; Hulscher, S.J.M.H.; Damme, van R.M.J.

    2003-01-01

    Sand waves form a prominent regular pattern in the offshore seabeds of sandy shallow seas. A two dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of these sand waves has been developed. The model contains the 2DV shallow water equations, with a free water su

  9. Regeneration of dredged sand waves

    NARCIS (Netherlands)

    Hulscher, Suzanne J.M.H.; Knaapen, Michiel; Scholl, Olaf; Scholl, O.; Trenteseaux., A.; Garlan, T.

    2000-01-01

    Sand waves form a wavy pattern in the offshore sandy seabed. Since their crests reduce the navigability, it is important to know their evolution. A simple model is presented to estimate the recovery of sand wave amplitudes. This model is partially based on the similarity with sea ripples and

  10. Shoaling of internal solitary waves at the ASIAEX site in the South China Sea

    Directory of Open Access Journals (Sweden)

    K. G. Lamb

    2014-07-01

    Full Text Available The interaction of barotropic tides with Luzon Strait topography generates westward propagating internal bores and solitary waves trains which eventually shoal and dissipate on the western side of the South China Sea. Two-dimensional numerical simulations of this shoaling process at the site of the Asian Seas International Acoustic Experiment (ASIAEX have been undertaken in order to investigate the sensitivity of the shoaling process to the stratification and the underlying bathymetry, and to explore the influence of rotation. A range of wave amplitudes are considered. Comparisons with adiabatic shoaling waves are also made and the potential impact of a non-slip boundary condition are briefly explored. On the slope secondary solitary waves and mode-two wave packets are generated which propagate towards the shelf. Comparisons with observations made during the ASIAEX experiment are made.

  11. Observations of Shoaling Nonlinear Internal Waves: Formation of Trapped Cores

    Science.gov (United States)

    Lien, R.; D'Asaro, E. A.; Chang, M.; Tang, T.; Yang, Y.

    2006-12-01

    Large-amplitude nonlinear internal waves (NLIWs) shoaling on the continental slope in the northern South China Sea are observed. Observed NLIWs often reach the breaking limit, the maximum horizontal current velocity exceeding the wave speed, and trapped cores are formed with recirculating fluid. The conjugate flow does not form. The vertical position of the maximum horizontal velocity is displaced from surface to subsurface, via the formation of the trapped core. Trapped-core NLIWs are strongly dissipative and evolve rapidly into trains of NLIWs. The vertical overturning is as large as 75 m, and the turbulence kinetic energy dissipation rate is estimated as O(10^{-5}) W kg-1. We propose that the formation and the evolution of trapped cores catalyze the generation of the trains of NLIWs on the Dongsha plateau often captured by satellite images and by recent field observations. The generation, evolution, fission, dissipation, and energetics of observed trapped-core NLIWs will be discussed and compared with results of numerical models and laboratory experiments.

  12. Sediment mathematical model for sand ridges and sand waves

    Institute of Scientific and Technical Information of China (English)

    LI Daming; WANG Xiao; WANG Xin; LI Yangyang

    2016-01-01

    A new theoretical model is formulated to describe internal movement mechanisms of the sand ridges and sand waves based on the momentum equation of a solid-liquid two-phase flow under a shear flow. Coupling this equation with two-dimensional shallow water equations and wave reflection-diffraction equation of mild slope, a two-dimensional coupling model is established and a validation is carried out by observed hydrogeology, tides, waves and sediment. The numerical results are compared with available observations. Satisfactory agreements are achieved. This coupling model is then applied to the Dongfang 1-1 Gas Field area to quantitatively predict the movement and evolution of submarine sand ridges and sand waves. As a result, it is found that the sand ridges and sand waves movement distance increases year by year, but the development trend is stable.

  13. Anatomy of a shoreface sand ridge revisited using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf

    Science.gov (United States)

    Robinson, M.M.; McBride, R.A.

    2008-01-01

    Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf ???5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

  14. Anatomy of a shoreface sand ridge revisted using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf

    Science.gov (United States)

    Robinson, Marci M.; McBride, Randolph A.

    2008-01-01

    Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf not, vert, ~5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

  15. Offshore sand-shoal development and evolution of Petit Bois Pass, Mississippi-Alabama Barrier Islands, Mississippi, USA

    Science.gov (United States)

    Flocks, James G.; Kelso, Kyle W.; Twichell, Gregory C.; Buster, Noreen A.; Baehr, John N.; Rosati, Julie D.; Wang, Ping; Roberts, Tiffany M.

    2011-01-01

    Assessment of recently collected geophysical and sediment-core data identifies an extensive shoal field located off Dauphin and Petit Bois Islands. The shoals are the product of Pleistocene fluvial deposition and Holocene marine-transgressive processes, and their position and orientation oblique to the modern shoreline has been stable over the past century. The underlying stratigraphy has also influenced the evolution of the barrier platform and inlets. Buried distributary channels bisect the platform, creating erosion hotspots that breach during intense and repeated storms. Inlet growth inhibits littoral transport, and over time, reduces the down-drift sand supply. These relations demonstrate the role of the antecedent geologic framework on morphologic evolution. This study is part of the USGS Northern Gulf of Mexico Ecosystem Change and Hazard Susceptibility Project and the USACE Mississippi Coastal Improvements Program. These projects produced a wealth of information regarding coastal geology, geomorphology, and physical resources; some of the initial results are presented here.

  16. Numerical modeling of convective instabilities in internal solitary waves of depression shoaling over gentle slopes

    Science.gov (United States)

    Rivera, Gustavo; Diamessis, Peter

    2016-11-01

    The shoaling of an internal solitary wave (ISW) of depression over gentle slopes is explored through fully nonlinear and non-hydrostatic simulations based on a high-accuracy deformed spectral multidomain penalty method. As recently observed in the South China Sea, in high-amplitude shoaling ISWs, the along-wave current can exceed the wave celerity resulting in convective instabilities. If the slope is less than 3%, the wave does not disintegrate as in the case of steeper slope shoaling but, instead, maintains its symmetric shape; the above convective instability may drive the formation of a turbulent recirculating core. The sensitivity of convective instabilities in an ISW is examined as a function of the bathymetric slope and wave steepness. ISWs are simulated propagating over both idealized and realistic bathymetry. Emphasis is placed on the structure of the above instabilities, the persistence of trapped cores and their potential for particle entrainment and transport. Additionally, the role of the baroclinic background current on the development of convective instabilities is explored. A preliminary understanding is obtained of the transition to turbulence within a high-amplitude ISW shoaling over progressively varying bathymetry.

  17. A Numerical Implementation of a Nonlinear Mild Slope Model for Shoaling Directional Waves

    Directory of Open Access Journals (Sweden)

    Justin R. Davis

    2014-02-01

    Full Text Available We describe the numerical implementation of a phase-resolving, nonlinear spectral model for shoaling directional waves over a mild sloping beach with straight parallel isobaths. The model accounts for non-linear, quadratic (triad wave interactions as well as shoaling and refraction. The model integrates the coupled, nonlinear hyperbolic evolution equations that describe the transformation of the complex Fourier amplitudes of the deep-water directional wave field. Because typical directional wave spectra (observed or produced by deep-water forecasting models such as WAVEWATCH III™ do not contain phase information, individual realizations are generated by associating a random phase to each Fourier mode. The approach provides a natural extension to the deep-water spectral wave models, and has the advantage of fully describing the shoaling wave stochastic process, i.e., the evolution of both the variance and higher order statistics (phase correlations, the latter related to the evolution of the wave shape. The numerical implementation (a Fortran 95/2003 code includes unidirectional (shore-perpendicular propagation as a special case. Interoperability, both with post-processing programs (e.g., MATLAB/Tecplot 360 and future model coupling (e.g., offshore wave conditions from WAVEWATCH III™, is promoted by using NetCDF-4/HD5 formatted output files. The capabilities of the model are demonstrated using a JONSWAP spectrum with a cos2s directional distribution, for shore-perpendicular and oblique propagation. The simulated wave transformation under combined shoaling, refraction and nonlinear interactions shows the expected generation of directional harmonics of the spectral peak and of infragravity (frequency <0.05 Hz waves. Current development efforts focus on analytic testing, development of additional physics modules essential for applications and validation with laboratory and field observations.

  18. Wave shoaling and diffraction in current over a mild-slope

    Institute of Scientific and Technical Information of China (English)

    LI Yucheng; LIU Deliang; CHEN Bing; LI Linpu

    2004-01-01

    The wave relative frequency in the coordinate system moving with current and the angle between the direction of wave propagation and that of current are computed based on the wave dispersion relation. The current field is computed by solving the depth averaged shallow water equations. The wave field is computed by solving the mildslope equation which has taken the current's effect into account. A numerical model is established using a finite element method for simulating the wave shoaling and diffraction in current over a mild-slope, and the numerical results are reasonable to compare with the experimental data.

  19. Numerical studies of large-amplitude internal waves shoaling and breaking at shelf slopes

    Science.gov (United States)

    Thiem, Øyvind; Berntsen, Jarle

    2009-12-01

    Hydro carbon fields beyond the shelf break are presently being explored and developed, which has increased the scientific focus in this area. Measurements from the slopes reveal large variability in temperature and velocity, and some of the observed events are due to interactions between large-amplitude oscillations of the thermocline and the topography. The present study focuses on the strong currents that are generated near the seabed during shoaling and breaking of internal waves along shelf slopes. The parameter regime used is similar to the one for the Nordic Seas. The results show that, during shoaling of large internal waves along (gentle) slopes, the energy is transferred towards smaller scales and strong velocities (over 1 m s - 1) can be generated. To resolve all scales involved is still not feasible, and therefore, the model results are sensitive to the grid size and the subgrid scale closure.

  20. Effects of Cape-Related Shoals on the Variability of Long Gravity Waves

    Science.gov (United States)

    Paniagua-Arroyave, J. F.; Adams, P. N.; Valle-Levinson, A.; Parra, S. M.

    2016-12-01

    Inner-shelf and shoreline morphology controls the generation, shoreline reflection, dissipation, and nearshore-trapping of long gravity waves (LGWs, frequencies from 4 to 40 mHz). In turn, LGWs variability exerts control on the morphodynamics of nearshore and surfzone environments. The variability of LGWs is poorly understood close to cuspate forelands and associated shoals. In order to study the effects of cape-related shoals on LGWs variability, water level (pressure) and velocity data were collected during Fall 2013 and Spring 2014 at swales landward and seaward of an isolated shoal (Shoal E) off Cape Canaveral, Florida. Landward and seaward cross-shore LGW energy fluxes were calculated from the auto- and coincident spectra of pressure and cross-shore velocities. Bulk LGW reflection coefficients (R2) were then quantified as the ratio of seaward to landward LGW energy fluxes. In general, for sea-swell HS>1.5 m, R2 varied from 0.3 to 0.6. These values were similar to R2 from locations close to the surfzone in a gently-sloping beach. In addition, values of R2 were higher at the seaward swale, e.g. when HS≈1.8 m, R2seaward≈0.6, and R2landward≈0.3. For sea-swell conditions HS1.5 m, R2seaward>R2landward and during calmer conditions R2seaward≈R2landward, implying the generation of seaward LGWs between swales for higher sea-swell conditions. In the latter case, LGWs may be produced via the time-varying breakpoint mechanism by short wave breaking over the shoal. Additionally, partial reflection by the shoal (like a breakwater for short waves) and refractive trapping close to it (conducive to edge wave formation) may further enhance seaward LGW energy fluxes, thus making R2seaward>R2landward. Our results are in general agreement with previous studies that investigated LGW reflections on gently-sloping beaches and provide preliminary evidence regarding the effects of cape-related bathymetry on the variability of LGWs.

  1. Optical tsunamis: shoaling of shallow water rogue waves in nonlinear fibers with normal dispersion

    CERN Document Server

    Wabnitz, Stefan

    2013-01-01

    In analogy with ocean waves running up towards the beach, shoaling of prechirped optical pulses may occur in the normal group-velocity dispersion regime of optical fibers. We present exact Riemann wave solutions of the optical shallow water equations and show that they agree remarkably well with the numerical solutions of the nonlinear Schr\\"odinger equation, at least up to the point where a vertical pulse front develops. We also reveal that extreme wave events or optical tsunamis may be generated in dispersion tapered fibers in the presence of higher-order dispersion.

  2. Sand Waves along the Dutch Coast

    NARCIS (Netherlands)

    Verhagen, H.J.

    1989-01-01

    Sand waves, defined as longshore wave-like movements of the shoreline, measured in a horizontal plane, are described along several stretches of the shoreline of The Netherlands. They have a celerity in the order of 50-200 m/yr, a period of 50- 150 years and an amplitude of 30- 500 m. They are found

  3. Simulating and understanding sand wave variation: A case study of the Golden Gate sand waves

    Science.gov (United States)

    Sterlini, F.; Hulscher, S.J.M.H.; Hanes, D.M.

    2009-01-01

    In this paper we present a detailed comparison between measured features of the Golden Gate sand wave field and the results of a nonlinear sand wave model. Because the Golden Gate sand waves exhibit large variation in their characteristics and in their environmental physics, this area gives us the opportunity to study sand wave variation between locations, within one well-measured, large area. The nonlinear model used in this paper is presently the only tool that provides information on the nonlinear evolution of large-amplitude sand waves. The model is used to increase our understanding of the coupling between the variability in environmental conditions and the sand wave characteristics. Results show that the model is able to describe the variation in the Golden Gate sand waves well when both the local oscillating tidal current and the residual current are taken into account. Current and water depth seem to be the most important factors influencing sand wave characteristics. The simulation results give further confidence in the underlying model hypothesis and assumptions. Copyright 2009 by the American Geophysical Union.

  4. Defining a relationship between incident wave parameters and morphologic evolution of shoals on ebb tidal deltas using long term X-band radar observation from RIOS

    Science.gov (United States)

    Humberston, J. L.; McNinch, J.; Lippmann, T. C.

    2016-12-01

    The morphology of tidal inlet ebb-shoals varies dynamically over time, particularly in response to large wave events. Understanding which wave qualities most influence shoals' evolution would support advancements in sediment bypassing models as well as targeted maintenance dredging for hydrographic purposes. Unfortunately, shallow and rapidly changing bathymetry, turbid waters and ambiguous wave speeds resulting from multiple shoaling and de-shoaling areas limits many traditional surveying techniques from obtaining the spatial and temporal resolution necessary to effectively characterize shoal development. The Radar Inlet Observing System (RIOS) is a uniquely designed mobile X-band radar system that can be deployed to inlet environments and, using roof-mounted solar panels and an automatically triggered highly efficient diesel generator, run automated hourly collections and wirelessly stream data for up to several months at a time in nearly all weather and water conditions. During 2015 and early 2016, RIOS was deployed to St. Augustine Inlet, FL., New River Inlet, N.C., and Oregon Inlet, N.C. for periods of one to six months to allow for measureable shoal evolution. During deployments, ten minute collections (at 1 Hz) were conducted every hour and the data gridded to a 5m alongshore/cross-shore grid. Raw intensity returns were time-averaged and analyzed to define three metrics of shoal evolution: movement direction, movement velocity and inferred bathymetry. For each location and time period, wave frequencies, wave directions and significant wave heights were collected from the nearest wave-buoy. Time lapse videos of shoal positions were inspected and used in concert with cross-correlations values from each pair of shoal and wave parameters to determine the incident wave qualities most strongly relating to shoal evolution. Preliminary results suggest wave height, more than frequency, controls shoal movement. Wave direction and size collaboratively appear to direct

  5. TURBULENT COHERENT STRUCTURES IN CHANNELS WITH SAND WAVES

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Sand wave bed is one of the typical shape of complicated boundaries in hydraulics and river dynamics, and sand wave motion is the main form of the bed load motion in-rivers, thence the study of turbulent structures over sand waves is of importance both in theory and practice. In this paper turbulent coherent structures over single-and multi-sand waves were studied experimentally, the formulae for the separation length and vortex shedding period of the turbulent flow over single-sand wave were suggested, and the characteristics of turbulent coherent structures over multi-sand waves were also given.

  6. Imaging of Acoustic Waves in Sand

    Energy Technology Data Exchange (ETDEWEB)

    Deason, Vance Albert; Telschow, Kenneth Louis; Watson, Scott Marshall

    2003-08-01

    There is considerable interest in detecting objects such as landmines shallowly buried in loose earth or sand. Various techniques involving microwave, acoustic, thermal and magnetic sensors have been used to detect such objects. Acoustic and microwave sensors have shown promise, especially if used together. In most cases, the sensor package is scanned over an area to eventually build up an image or map of anomalies. We are proposing an alternate, acoustic method that directly provides an image of acoustic waves in sand or soil, and their interaction with buried objects. The INEEL Laser Ultrasonic Camera utilizes dynamic holography within photorefractive recording materials. This permits one to image and demodulate acoustic waves on surfaces in real time, without scanning. A video image is produced where intensity is directly and linearly proportional to surface motion. Both specular and diffusely reflecting surfaces can be accomodated and surface motion as small as 0.1 nm can be quantitatively detected. This system was used to directly image acoustic surface waves in sand as well as in solid objects. Waves as frequencies of 16 kHz were generated using modified acoustic speakers. These waves were directed through sand toward partially buried objects. The sand container was not on a vibration isolation table, but sat on the lab floor. Interaction of wavefronts with buried objects showed reflection, diffraction and interference effects that could provide clues to location and characteristics of buried objects. Although results are preliminary, success in this effort suggests that this method could be applied to detection of buried landmines or other near-surface items such as pipes and tanks.

  7. Variations of wave energy power in shoaling zone of Benin coastal zone

    Directory of Open Access Journals (Sweden)

    Mathias A. Houekpoheha

    2015-02-01

    Full Text Available Today, we observe at the population level, that the improvement in comfort is accompanied by an increase in the electrical energy required. The predicted exhaustion of fossil energy resources maintains some speculation. Their unequal geographical distribution justifies the energy dependence of Benin overlooked from outside. So it is urgent to explore the various sources of renewable energy available to Benin. In this work, using measurements made ​​by the Millennium Challenge Account (MCA-Benin as part of the extension of the port of Cotonou, with Boussinesq equations (Peregrine and Stokes waves dispersion relation, we characterized the variations of various swell parameters (height, wavelength, velocities in the shoaling zone on the study site and proceeded to estimate variations in wave energy power from deep waters to the bathymetric breaking point. Finally, the zone with high energy power (where the conversion of this energy into electrical energy would be profitable of these waves is highlighted on the site, the local water depth at the point of breaking waves is evaluated and results obtained allowed to justify the very energetic character take by these swells on this coast when they are close to the beach.

  8. Efficient modelling of sand wave behaviour [Powerpoint Presentation

    NARCIS (Netherlands)

    Berg, van den Joris; Damme, van Ruud

    2004-01-01

    Sand waves form a pattern of more or less parallel ridges. The wave length is about 300 meters and the height up to 10 meters, which is a considerable amount of the total water depth. Sand waves migrate with speeds of about 10 meters per year. Information on their behaviour is valuable: the larger p

  9. Infra-Gravity Wave Generation by the Shoaling Wave Groups over Beaches

    Institute of Scientific and Technical Information of China (English)

    LIN Yu-Hsien; HWUNG Hwung-Hweng

    2012-01-01

    A physical parameter,μb,which was used to meet the forcing of primary short waves to be off-resonant before wave breaking,has been considered as an applicable parameter in the infra-gravity wave generation.Since a series of modulating wave groups for different wave conditions are performed to proceed with the resonant mechanism of infragravity waves prior to wave breaking,the amplitude growth of incident bound long wave is assumed to be simply controlled by the normalized bed slope,βb.The results appear a large dependence of the growth rate,α,of incident bound long wave,separated by the three-array method,on the normalized bed slope,βb.High spatial resolution of wave records enables identification of the cross-correlation between squared short-wave envelopes and infra-gravity waves.The crossshore structure of infra-gravity waves over beaches presents the mechanics of incident bound- and outgoing free long waves with the formation of free standing long waves in the nearshore region.The wave run-up and amplification of infra-gravity waves in the swash zone appear that the additional long waves generated by the breaking process would modify the cross-shore structure of free standing long waves.Finally,this paper would further discuss the contribution of long wave breaking and bottom friction to the energy dissipation of infra-gravity waves based on different slope conditions.

  10. Modeling sheet-flow sand transport under progressive surface waves

    NARCIS (Netherlands)

    Kranenburg, W.M.

    2013-01-01

    In the near-shore zone, energetic sea waves generate sheet-flow sand transport. In present day coastal models, wave-induced sheet-flow sand transport rates are usually predicted with semi-empirical transport formulas, based on extensive research on this phenomenon in oscillatory flow tunnels. Howeve

  11. Sand Wave Migrations Within Monterey Submarine Canyon, California

    Science.gov (United States)

    Xu, J.; Wong, F. L.

    2006-12-01

    Repeated high-resolution multi-beam surveys revealed the existence of a sand wave field along the axis of the Monterey submarine canyon between 20 and 300 m water depth. These sand waves range in wave length from 20 to 70 m and 2 to 5 m in height. Comparison of sequential multi-beam grid data (months apart) indicates that the sand waves apparently migrate upcanyon at some places while the same data clearly show that the sand waves migrate downcanyon at other locations. One hypothesis is that strong internal tidal flows, whose upcanyon component is intensified by the narrow canyon, are responsible for forming the sand wave field and for migrating the sand waves upcanyon. Another hypothesis is that the sand wave field is formed by creeping (analogous to the movement within glaciers), and in general they move in the downcanyon direction. A field experiment was conducted in 2005-06 to measure the driving forces (in hypothesis #1) that form and move the sand waves, and to collect the internal sedimentological structure within the sand waves that could reveal information on hypothesis #2. A mooring designed to measure near-floor velocity profiles, temperature, salinity, and sediment concentration in the water column was deployed for one year (June 2005 -July 2006) at 250 m water depth, slightly downcanyon of the sand wave field. In addition, a mapping survey was conducted in February, 2006 for collecting multi-beam and chirp profiles in the canyon head area of the sand wave field. Preliminary examination of the ADCP (downward looking) showed some very interesting features - the near- floor current dramatically changes with the spring-neap cycle of the surface tide. The time variation of the along-canyon current during neap tides - a sudden jump of upcanyon velocity before gradually tapering down, is typical of internal tides (internal bores). The time variation during spring tides when along canyon velocities reverse directions from upcanyon to downcanyon and gradually

  12. Whales and waves: Humpback whale foraging response and the shoaling of internal waves at Stellwagen Bank

    Science.gov (United States)

    Pineda, Jesús; Starczak, Victoria; Silva, José C. B.; Helfrich, Karl; Thompson, Michael; Wiley, David

    2015-04-01

    We tested the hypothesis that humpback whales aggregate at the southern flank of Stellwagen Bank (SB) in response to internal waves (IWs) generated semidiurnally at Race Point (RP) channel because of the presence of their preferred prey, planktivorous fish, which in turn respond to zooplankton concentrated by the predictable IWs. Analysis of synthetic aperture radar (SAR) images indicates that RP IWs approach the southern flank of SB frequently (˜62% of the images). Published reports of whale sighting data and archived SAR images point to a coarse spatial coincidence between whales and Race Point IWs at SB's southern flank. The responses of whales to IWs were evaluated via sightings and behavior of humpback whales, and IWs were observed in situ by acoustic backscatter and temperature measurements. Modeling of IWs complemented the observations, and results indicate a change of ˜0.4 m/s in current velocity, and ˜1.5 Pa in dynamic pressure near the bottom, which may be sufficient for bottom fish to detect the IWs. However, fish were rare in our acoustic observations, and fish response to the IWs could not be evaluated. RP IWs do not represent the leading edge of the internal tide, and they may have less mass-transport potential than typical coastal IWs. There was large interannual variability in whale sightings at SB's southern flank, with decreases in both numbers of sightings and proportion of sightings where feeding was observed from 2008 to 2013. Coincidence of whales and IWs was inconsistent, and results do not support the hypothesis.

  13. 吸砂船施工技术在钱塘江东江嘴切滩工程中的应用%Application of Construction Technology of Inhale Sand Ships in the Dongjiangzui Shoal Cutting Projectat Qiantang River

    Institute of Scientific and Technical Information of China (English)

    王泽斌; 徐昌栋

    2012-01-01

    东江嘴切滩是解决钱塘江闻家堰弯道防洪瓶颈问题的关键。采用传统技术切滩成本较高,土方弃置场地难解决,实际工程实施中利用东江嘴高滩下蕴藏有丰富黄砂的有利条件,采用吸砂船取砂切滩施工,不仅技术上可行,且施工工期短,节省工程投资。%Dongjiangzui shoal cutting project is the key part to solve the bottleneck problem of flood control at the Wenjiayan riverbend. The cost of traditional techniques for shoal cutting is too high and the ground for discarded earth is hard to find. During engineering implementation, we found that there is lots of sands down under the Dongjiangzui Shoal. Therefore, we take theadvantage of this fact to cut the shoal by using the inhale sand ship. This measure was not only technically feasible but alsofinancially feasible, and shortened the construction stage.

  14. Investigation of guided waves propagation in pipe buried in sand

    Energy Technology Data Exchange (ETDEWEB)

    Leinov, Eli; Cawley, Peter; Lowe, Michael J.S. [NDE Group, Department of Mechanical Engineering, Imperial College London, London SW7 2AZ (United Kingdom)

    2014-02-18

    The inspection of pipelines by guided wave testing is a well-established method for the detection of corrosion defects in pipelines, and is currently used routinely in a variety of industries, e.g. petrochemical and energy. When the method is applied to pipes buried in soil, test ranges tend to be significantly compromised because of attenuation of the waves caused by energy radiating into the soil. Moreover, the variability of soil conditions dictates different attenuation characteristics, which in-turn results in different, unpredictable, test ranges. We investigate experimentally the propagation and attenuation characteristics of guided waves in pipes buried in fine sand using a well characterized full scale experimental apparatus. The apparatus consists of an 8 inch-diameter, 5.6-meters long steel pipe embedded over 3 meters of its length in a rectangular container filled with fine sand, and an air-bladder for the application of overburden pressure. Longitudinal and torsional guided waves are excited in the pipe and recorded using a transducer ring (Guided Ultrasonics Ltd). Acoustic properties of the sand are measured independently in-situ and used to make model predictions of wave behavior in the buried pipe. We present the methodology and the systematic measurements of the guided waves under a range of conditions, including loose and compacted sand. It is found that the application of overburden pressure modifies the compaction of the sand and increases the attenuation, and that the measurement of the acoustic properties of sand allows model prediction of the attenuation of guided waves in buried pipes with a high level of confidence.

  15. Giant sand waves at the mouth of San Francisco Bay

    Science.gov (United States)

    Barnard, P.L.; Hanes, D.M.; Rubin, D.M.; Kvitek, R.G.

    2006-01-01

    A field of giant sand waves, among the largest in the world, recently was mapped in high resolution for the first time during a multibeam survey in 2004 and 2005 through the strait of the Golden Gate at the mouth of San Francisco Bay in California (Figure la). This massive bed form field covers an area of approximately four square kilometers in water depths ranging from 30 to 106 meters, featuring more than 40 distinct sand waves with crests aligned approximately perpendicular to the dominant tidally generated cross-shore currents, with wavelengths and heights that measure up to 220 meters and 10 meters, respectively. Sand wave crests can be traced continuously for up to two kilometers across the mouth of this energetic tidal inlet, where depth-averaged tidal currents through the strait below the Golden Gate Bridge exceed 2.5 meters per second during peak ebb flows. Repeated surveys demonstrated that the sand waves are active and dynamic features that move in response to tidally generated currents. The complex temporal and spatial variations in wave and tidal current interactions in this region result in an astoundingly diverse array of bed form morphologies, scales, and orientations. Bed forms of approximately half the scale of those reported in this article previously were mapped inside San Francisco Bay during a multibeam survey in 1997 [Chin et al., 1997].

  16. Sand Bed Morphodynamics under Standing Waves and Vegetated Conditions

    Science.gov (United States)

    Landry, B. J.; Garcia, M. H.

    2010-12-01

    Littoral processes such as sediment transport, wave attenuation, and boundary layer development are governed by the presence of bathymetric features, which include large-scale sand bars upon which smaller-scale sand ripples are superimposed, as well as the presence of submarine vegetation. Numerous studies on sand ripples and bars have aided to elucidate the dynamics in oscillatory flows; however, the effect of vegetation on the system is less understood. Recent laboratory studies have focused on quantifying wave attenuation by emergent vegetation as a natural method to mitigate storm surges. The emergent vegetation, while promising for coastal protection, alters sediment transport rates directly by the physical presence of the plants near the bed and indirectly from reduction in near-bed shear stresses due to attenuated wave energy. The experimental work herein focuses on the area near the deeply submerged vegetated canopy limit (current work has a ratio of mean still water depth to plant height, H/h, = 7.9) to minimize the effect on the surface waves and discern the direct impact vegetation has on sand bed morphodynamics. Experiments were conducted in the large wave tank (49-m long by 1.83-m wide by 1.22-m deep) in the Ven Te Chow Hydrosystems Laboratory at the University of Illinois in which a high reflection wave forcing was used over a uniform sand bed with a 0.25-mm median sediment diameter in which staggered and uniform arrangements of idealized vegetation (i.e., 6.35-mm diameter rigid wooden cylinders) were positioned along the bed (e.g., at predetermined sand bar troughs and over an entire sand bar). The resulting bathymetric evolution from the vegetated case experiments were compared to the base case of no vegetation using two optical methods: a high-resolution laser displacement sensor for three-dimensional surveys and digitized profiles via high-definition panoramic images of the entire test section. The experimental findings illustrate the profound

  17. Dynamical models for sand ripples beneath surface waves

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Chabanol, M.-L.; v. Hecke, M.

    2001-01-01

    We introduce order parameter models for describing the dynamics of sand ripple patterns under oscillatory flow. A crucial ingredient of these models is the mass transport between adjacent ripples, which we obtain from detailed numerical simulations for a range of ripple sizes. Using this mass...... transport function, our models predict the existence of a stable band of wave numbers limited by secondary instabilities. Small ripples coarsen in our models and this process leads to a sharply selected final wave number, in agreement with experimental observations....

  18. Sand Waves in Environmental Flows: Insights gained by LES

    Science.gov (United States)

    Sotiropoulos, Fotis

    2014-11-01

    In fluvial and coastal environments, sediment transport processes induced by near-bed coherent structures in the turbulent boundary layer developing over a mobile sediment bed result in the formation of dynamically rich sand waves, or bed forms, which grow and migrate continuously. Bed form migration alters streambed roughness and provides the primary mechanism for transporting large amounts of sediment through riverine systems impacting the morphology, streambank stability, and ecology of waterways. I will present recent computational advances, which have enabled coupled, hydro-morphodynamic large-eddy simulation (LES) of turbulent flow in mobile-bed open channels. Numerical simulations: 1) elucidate the role of near-bed sweeps in the turbulent boundary layer as the mechanism for initiating the instability of the initially flat sand bed; 2) show how near-bed processes give rise to aperiodic eruptions of suspended sediment at the free surface; and 3) clarify the mechanism via which sand waves migrate. Furthermore, in agreement with recent experimental observations, the computed spectra of the resolved velocity fluctuations above the bed exhibit a distinct spectral gap whose width increases with distance from the bed. The spectral gap delineates the spectrum of turbulence from that of slowly evolving coherent structures associated with sand wave migration. The talk will also present computational results demonstrating the feasibility of carrying out coupled, hydro-morphodynamic LES of large dunes migrating in meandering streams and rivers with embedded hydraulic structures and discuss future challenges and opportunities. This work was supported by NSF Grants EAR-0120914 and EAR-0738726, and National Cooperative Highway Research Program Grant NCHRP-HR 24-33.

  19. A shoreline sand wave formation event at Dungeness, UK.

    Science.gov (United States)

    Falqués, A.; Arriaga, J.; Francesca, R.; Eddie, C.

    2016-12-01

    Alongshore rhythmic morphological patterns at different length scales are quite common along sandy beaches. Well known examples are megacusps and crescentic bars/rip channel systems with alongshore wavelengths ˜ 100-1000 m. At larger scales (˜ 1-10 km or more) there are the km-scale shoreline sand waves. During the last two decades there has been much research to unravel the origin of such intriguing patterns and to get insight into their dynamics. The hypothesis that they emerge out of positive feedbacks between hydrodynamics and morphology has been amply confirmed by mathematical modelling. In particular, the potential role of high-angle waves (large incidence angles with respect to shore) in driving km-scale shoreline sand waves has been investigated (Ashton et al., 2001, van den Berg et al., 2012). However, direct tests with nature are very difficult and are inexistent to our knowledge. This is so because these tests would require detailed measurements of the bathymetry and the wave conditions at the moment of their formation from a featureless morphology. Dungeness beach is located at the English shore of the Dover straight facing northeast part of a cuspate foreland. It is a gravel beach (D50=6-10 mm) quite steep until 1 m depth (β≈0.13) and gentle until 3 m depth (β≈0.005) without shore-parallel bars. Bathymetric maps of this beach are available since 2007 and the wave conditions are also known from a wave buoy in 43 m depth. The shorelines from 2007 until 2013 show some subtle and evolving undulations. But remarkably, in 2014 a series of two undulations develop with a wavelength of about 0.5 km. They persist until 2016 and migrate to the N. This is a clear formation event that provides a unique opportunity to compare observations with the outputs of morphodynamic models for the initial formation of such features. Therefore, the objectives are: 1) Characterize the bathymetric evolution and the wave conditions prior/during the formation event, 2) run

  20. Patch behaviour and predictability properties of modelled finite-amplitude sand ridges on the inner shelf

    NARCIS (Netherlands)

    Vis-star, N.C.; de Swart, H.E.; Calvete, D.

    2008-01-01

    The long-term evolution of shoreface-connected sand ridges is investigated with a nonlinear spectral model which governs the dynamics of waves, currents, sediment transport and the bed level on the inner shelf. Wave variables are calculated with a shoaling-refraction model instead of using a paramet

  1. Laboratory monitoring of P-waves in partially saturated sand

    Science.gov (United States)

    Barrière, J.; Bordes, C.; Brito, D.; Sénéchal, P.; Perroud, H.

    2011-12-01

    Seismic data depends on a variety of hydrogeological properties of the prospected porous media such as porosity, permeability and fluid saturation. We have performed a laboratory experiment in the kiloHertz range in order to analyze the role of partial saturation on direct propagating P-waves phase velocity and attenuation. The experiment consists of a sand-filled tank 107 cm x 34 cm x 35cm equipped with accelerometers and water capacitance probes. The P-waves seismic propagation is generated by hitting a steel ball on a granite plate on the one lateral side of the container. Several imbibition/drainage cycles are performed between the water residual saturation and the gas residual saturation. The laboratory seismic data are processed by two Continuous Wavelet Transforms using one real mother wavelet (Mexican hat) and one complex (Morlet) to recover velocity and attenuation as a function of frequency. Phase velocity of direct P-wave decreases with an increase of water content and is quite consistent with the low frequency limit of the Biot's theory both for imbibition and drainage. The interpretation of the P-waves attenuation needs to go beyond the macroscopic fluid flow of Biot's theory and to introduce a viscoelastic contribution linked to the grain to grain overall losses which are described by a constant Q-model. A strong hysteresis between imbibition and drainage is observed and explained by introducing an effective permeability depending on water and gas relative permeabilities (Van Genuchten model).

  2. Effects of charged sand on electromagnetic wave propagation and its scattering field

    Institute of Scientific and Technical Information of China (English)

    HE; Qinshu; ZHOU; Youhe; ZHENG; Xiaojing

    2006-01-01

    Based on the Rayleigh's scattering theory, the effects of sandstorms on the propagation of electromagnetic wave with different visibilities are presented by solving the scattering field of charged sand particles. Because of the electric charges on the sand surface, the theoretical attenuation will be large enough to match the measured value under certain conditions. And the results show that the effect of sand with electric charges all over its surface on electromagnetic wave attenuation is the same as that of sand without charge, which proves that electric charges distribute on partial surface of the sand in fact.

  3. The role of suspended load transport in the occurrence of tidal sand waves

    NARCIS (Netherlands)

    Borsje, B.W.; Kranenburg, W.M.; Roos, P.C.; Matthieu, J.; Hulscher, S.J.M.H.

    2014-01-01

    Tidal sand waves are dynamic bed patterns which are formed by the complex interaction between hydrodynamics, sediment transport, and geomorphology. Field data from the southern North Sea reveal that sand waves are absent where suspended load transport is the dominant transport mode. In order to unde

  4. Scour at Vertical Piles in Sand-Clay Mixtures under Waves

    DEFF Research Database (Denmark)

    Dey, Subhasish; Helkjær, Anders; Sumer, B. Mutlu;

    2011-01-01

    Marine sediments often contain sand-clay mixtures in widely varying proportions. This study presents the results of equilibrium scour and time variation of scour depths at circular piles embedded vertically in clay alone and sand-clay mixed beds under waves. Experiments were conducted in a wave f...

  5. The role of suspended load transport in the occurrence of tidal sand waves

    NARCIS (Netherlands)

    Borsje, Bastiaan Wijnand; Kranenburg, Wouter; Roos, Pieter C.; Matthieu, J.; Hulscher, Suzanne J.M.H.

    2014-01-01

    Tidal sand waves are dynamic bed patterns which are formed by the complex interaction between hydrodynamics, sediment transport, and geomorphology. Field data from the southern North Sea reveal that sand waves are absent where suspended load transport is the dominant transport mode. In order to unde

  6. The influence of storms on finite amplitude sand wave dynamics: an idealized nonlinear model

    NARCIS (Netherlands)

    Campmans, G.H.P.; Roos, P.C.; de Vriend, H.J.; Hulscher, S.J.M.H.

    2017-01-01

    We investigate the effects of storms on finite amplitude sand wave growth using a new idealized nonlinear morphodynamic model. We find that the growth speed initially linearly increases with sand wave amplitude, after which nonlinear effects cause the growth to decrease. This finally leads to an

  7. Pleistocene barrier bar seaward of ooid shoal complex near Miami, Florida

    Science.gov (United States)

    Halley, Robert B.; Shinn, Eugene A.; Hudson, J. Harold; Lidz, Barbara H.

    1977-01-01

    An ooid sand barrier bar of Pleistocene age was deposited along the seaward side of an ooid shoal complex southwest of Miami, Florida. The bar is 35 km long, about 0.8 km wide, elongate parallel with the trend of the ooid shoal complex and perpendicular to channels between individual shoals. A depression 1.6 km wide, interpreted as a back-barrier channel, isolates the bar from the ooid shoals. During sea-level fall and subaerial exposure of the bar, the ooid sand was cemented in place, preventing migration of the barrier. No Holocene analogue of this sand body is recognized, perhaps because of the relative youthfulness of Holocene ooid shoals. This Pleistocene ooid shoal complex, with its reservoir-size barrier bar, may serve as a refined model for exploration in ancient ooid sand belts.

  8. Assessment of existing sediment transport models for sand barrier dynamics under wave and currents

    Digital Repository Service at National Institute of Oceanography (India)

    Thuy, T.T.V.; Nghiem, L.T.; Jayakumar, S.; Nielsen, P.

    The paper summarizes morphology changes over rippled sand barriers under wave and wave combined current of 27 laboratorial experiments. Data of 4 wave conditions (H=10cm, T=1s; H=12cm, T=1s; H=12cm, T=1.5s; H=14cm, T=1.5s) and 6 currents (Q= 10, -10...

  9. Stress Wave Propagation in Unsaturated Sands. Volume 1. Centrifuge Modeling

    Science.gov (United States)

    1993-04-01

    122 xii LIST OF TABLES 2.1 Soil properties from explosive testing in sand by Drake and Little (1983...Ottawa, Illinois (ASTM C190). A summary of the physical properties of both Tyndall and Ottawa sands is given in Tablas 3.3a and 3.3b. Grain size

  10. Numerical research on evolvement of submarine sand waves in the Northern South China Sea

    Science.gov (United States)

    Zhou, Qikun; Hu, Guanghai; Sun, Yongfu; Liu, Xiaohui; Song, Yupeng; Dong, Lifeng; Dong, Changming

    2016-05-01

    Submarine sand waves, vital to seabed stability, are an important consideration for oceanic engineering projects such as oil pipe lines and submarine cables. The properties of surface sediment and the evolvement of submarine sand waves in a specified area in the South China Sea are studied using both a hydrological model and field observational data. The bottom flow field data between 2010 and 2011 in the study area are simulated by the Regional Ocean Model System (ROMS). The migration of submarine sand waves is calculated using Rubin's formula along with typhoon data and bottom flow field data, which allows for the analysis of sand wave response under the influence of typhoons. The migration direction calculated by Rubin's formula and bottom flow are very similar to collected data. The migration distance of different positions is between 0.0 m and 21.8 m, which reciprocates cumulatively. This shows that Rubin's formula can predict the progress of submarine sand waves with the bottom flow simulated by ROMS. The migration distances of 2 sites in the study area are 2.0 m and 2.9 m during the typhoon "Fanapi". The proportion of the calculated migration distance by the typhoon is 9.17% and 26.36% of the annual migration distance, respectively, which proves that the typhoon can make a significant impact on submarine sand waves.

  11. Numerical research on evolvement of submarine sand waves in the Northern South China Sea

    Science.gov (United States)

    Zhou, Qikun; Hu, Guanghai; Sun, Yongfu; Liu, Xiaohui; Song, Yupeng; Dong, Lifeng; Dong, Changming

    2017-03-01

    Submarine sand waves, vital to seabed stability, are an important consideration for oceanic engineering projects such as oil pipe lines and submarine cables. The properties of surface sediment and the evolvement of submarine sand waves in a specified area in the South China Sea are studied using both a hydrological model and field observational data. The bottom flow field data between 2010 and 2011 in the study area are simulated by the Regional Ocean Model System (ROMS). The migration of submarine sand waves is calculated using Rubin's formula along with typhoon data and bottom flow field data, which allows for the analysis of sand wave response under the influence of typhoons. The migration direction calculated by Rubin's formula and bottom flow are very similar to collected data. The migration distance of different positions is between 0.0 m and 21.8 m, which reciprocates cumulatively. This shows that Rubin's formula can predict the progress of submarine sand waves with the bottom flow simulated by ROMS. The migration distances of 2 sites in the study area are 2.0 m and 2.9 m during the typhoon "Fanapi". The proportion of the calculated migration distance by the typhoon is 9.17% and 26.36% of the annual migration distance, respectively, which proves that the typhoon can make a significant impact on submarine sand waves.

  12. Longshore sediment transport at Golden Sands (Bulgaria

    Directory of Open Access Journals (Sweden)

    Hristo Nikolov

    2006-09-01

    Full Text Available The paper presents the results of studies on the qualitative and quantitative features of the littoral drift at Golden Sands (Bulgaria, carried out jointly by Polish and Bulgarian researchers. The mathematical modelling of physical coastal processes took wave transformation (wave diffraction and refraction; the effects of shoaling and wave breaking and longshore sediment transport into account. The computations were carried out for the mean statistical annual wave climate, determined on the basis of IO BAS wave data, simulated using the WAM method from long-term Black Sea wind data. The results of sediment transport computations clearly show that its direction off the Golden Sands shore is from north to south.

  13. Model of inner shelf shoal development, Beaufort Sea, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Lowry, P.; Nummedal, D.; Reimnitz, E.

    1985-01-01

    At least two types of inner shelf shoals exist in the Beaufort Sea, Alaska. One type is located up to 40 km from the shoreline in an average water depth of 20m and oriented obliquely to the coast. A second type of shoals occur adjacent to existing barrier islands where minimum water depth over the shoal crest may be as little as 30-50cm. The development of shallow water shoals is believed to be a result of barrier island submergence. Dinkum Sands is an example of a shallow water shoal. This linear sand body is located between Cross and Narwhal Islands, 25km northeast of Prudhoe Bay. The shoal complex is 8 km long and less than 2 km wide and has a maximum relief of 5m. Historical data reveal submergence of an island over at least a 25 year period. The proposed initial stage of shoal development occurs when longshore sediment transport between barrier islands is disrupted by numerous events of downdrift tidal inlet breaching. Reduction in the amount of available sediment to each island results in significant coastal erosion (stage 2), manifest as a landward migration of the shoreline and a reduction in barrier elevation. The final stage of the model is barrier submergence. At present the greatest accumulation of sediment on Dinkum Sands occur at the distal extremities of the shoal. These are believed to represent the location of recurved spits at either end of the island prior to submergence. Application of the submergence model to explain deepwater shoal development must await the collection of shallow (10m) whole core data.

  14. Passive millimeter-wave imagery of helicopter obstacles in a sand environment

    Science.gov (United States)

    Wikner, David A.

    2006-05-01

    Operation of military helicopters in a dusty environment challenges pilots with reduced visibility. Passive millimeter-wave (MMW) imaging has the potential to be used in these environments to image through dust cloud obscurants. The millimeter-wave phenomenology of the sand environment and the obstacles present in that environment are explored in this work. A 93 GHz polarimetric passive MMW imager was used to characterize an obstacle-rich sand environment and the results are presented. It is shown that there is a strong polarimetric signature present for both sand and cinder block between 10 and 30 degrees depression angles. Also shown is the phenomenology associated with shadows on sand. It was determined that berms and ditches can be very difficult to detect using even a sensitive MMW radiometer. The results can be used to model the performance of passive MMW imaging systems in a sandy environment.

  15. Dynamics of Nearshore Sand Bars and Infra-gravity Waves: The Optimal Theory Point of View

    Science.gov (United States)

    Bouchette, F.; Mohammadi, B.

    2016-12-01

    It is well known that the dynamics of near-shore sand bars are partly controlled by the features (location of nodes, amplitude, length, period) of the so-called infra-gravity waves. Reciprocally, changes in the location, size and shape of near-shore sand bars can control wave/wave interactions which in their turn alter the infra-gravity content of the near-shore wave energy spectrum. The coupling infra-gravity / near-shore bar is thus definitely two ways. Regarding numerical modelling, several approaches have already been considered to analyze such coupled dynamics. Most of them are based on the following strategy: 1) define an energy spectrum including infra-gravity, 2) tentatively compute the radiation stresses driven by this energy spectrum, 3) compute sediment transport and changes in the seabottom elevation including sand bars, 4) loop on the computation of infra-gravity taking into account the morphological changes. In this work, we consider an alternative approach named Nearshore Optimal Theory, which is a kind of breakdown point of view for the modeling of near-shore hydro-morphodynamics and wave/ wave/ seabottom interactions. Optimal theory applied to near-shore hydro-morphodynamics arose with the design of solid coastal defense structures by shape optimization methods, and is being now extended in order to model dynamics of any near-shore system combining waves and sand. The basics are the following: the near-shore system state is through a functional J representative of the energy of the system in some way. This J is computed from a model embedding the physics to be studied only (here hydrodynamics forced by simple infra-gravity). Then the paradigm is to say that the system will evolve so that the energy J tends to minimize. No really matter the complexity of wave propagation nor wave/bottom interactions. As soon as J embeds the physics to be explored, the method does not require a comprehensive modeling. Near-shore Optimal Theory has already given

  16. Wave Characteristics at the South Part of the Radial Sand Ridges of the Southern Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    杨斌; 冯卫兵; 张俞

    2014-01-01

    Based on one-year wave field data measured at the south part of the radial sand ridges of the Southern Yellow Sea, the wave statistical characteristics, wave spectrum and wave group properties are analyzed. The results show that the significant wave height (H1/3) varies from 0.15 to 2.22 m with the average of 0.59 m and the mean wave period (Tmean) varies from 2.06 to 6.82 s with the average of 3.71 s. The percentage of single peak in the wave spectra is 88.6 during the measurement period, in which 36.3%of the waves are pure wind waves and the rest are young swells. The percentage with the significant wave height larger than 1 m is 12.4. The dominant wave directions in the study area are WNW, W, ESE, E and NW. The relationships among the characteristic wave heights, the characteristic wave periods, and the wave spectral parameters are identified. It is found that the tentative spectral model is suitable for the quantitative description of the wave spectrum in the study area, while the run lengths of the wave group estimated from the measured data are generally larger than those in other sea areas.

  17. Extended Elliptic Mild Slope Equation Incorporating the Nonlinear Shoaling Effect

    Directory of Open Access Journals (Sweden)

    Xiao Qian-lu

    2016-10-01

    Full Text Available The transformation during wave propagation is significantly important for the calculations of hydraulic and coastal engineering, as well as the sediment transport. The exact wave height deformation calculation on the coasts is essential to near-shore hydrodynamics research and the structure design of coastal engineering. According to the wave shoaling results gained from the elliptical cosine wave theory, the nonlinear wave dispersion relation is adopted to develop the expression of the corresponding nonlinear wave shoaling coefficient. Based on the extended elliptic mild slope equation, an efficient wave numerical model is presented in this paper for predicting wave deformation across the complex topography and the surf zone, incorporating the nonlinear wave dispersion relation, the nonlinear wave shoaling coefficient and other energy dissipation factors. Especially, the phenomenon of wave recovery and second breaking could be shown by the present model. The classical Berkhoff single elliptic topography wave tests, the sinusoidal varying topography experiment, and complex composite slopes wave flume experiments are applied to verify the accuracy of the calculation of wave heights. Compared with experimental data, good agreements are found upon single elliptical topography and one-dimensional beach profiles, including uniform slope and step-type profiles. The results indicate that the newly-developed nonlinear wave shoaling coefficient improves the calculated accuracy of wave transformation in the surf zone efficiently, and the wave breaking is the key factor affecting the wave characteristics and need to be considered in the nearshore wave simulations.

  18. A LINEAR THEORY FOR DISTURBANCE OF COHERENT STRUCTURE AND MECHANISM OF SAND WAVES IN OPEN-CHANNEL FLOW

    Institute of Scientific and Technical Information of China (English)

    Yuchuan BAI; Andreas MALCHEREK; Changbo JIANG

    2001-01-01

    The formation of sand wave is such a process in which the roughness and discontinuity of the original bed surface cause the disturbance of the bottom laminar flow in an open channel,and the development of the disturbance in turn leads to instability of the flow and the appearance of the coherent structure. The evolution and development of the coherent structure further promote the undulations of bed surface and sand waves rise finally. The sand wave is explained as a result of action that the bed sediment particles are disturbed by the coherent structure. This study shows that the sand wave formation is the result of disturbance action of neutral coherent structure, and the sand wave shape obtained in computations is identical to the practical one.

  19. Introduction to special section on marine sand wave and river dune dynamics

    NARCIS (Netherlands)

    Hulscher, Suzanne J.M.H.; Dohmen-Janssen, C. Marjolein

    2005-01-01

    Marine sand waves and river dunes are rhythmic patterns, formed at the interface between a sandy bed and turbulent flows, driven by tidal and river currents. Their origin, development, and dynamics are far from being fully understood. To enhance the discussion on this topic we organized the internat

  20. On the parameterization of biological influences on offshore sand wave dynamics

    NARCIS (Netherlands)

    Borsje, B.W.; Hulscher, S.J.M.H.; Herman, P.M.J.; De Vries, M.B.

    2009-01-01

    The bed of the North Sea is covered by sand waves and houses a great number of macrobenthic animals. These bio-engineers are known to have a significant influence on the stability of the bed and thereby on the geomorphology of the seabed. This paper proposes a parameterization of these bio-geomorpho

  1. Cyclic behavior of sandy shoals on the ebb-tidal deltas of the Wadden Sea

    NARCIS (Netherlands)

    Ridderinkhof, W.; Hoekstra, P.; van der Vegt, M.; de Swart, H. E.

    2016-01-01

    Ebb-tidal deltas are bulges of sand that are located seaward of tidal inlets. Many of these deltas feature shoals that cyclically form and migrate towards the coast. The average period between successive shoals that attach to the coast varies among different inlets. In this study, a quantitative ass

  2. Release of Escherichia coli from Foreshore Sand and Pore Water during Intensified Wave Conditions at a Recreational Beach.

    Science.gov (United States)

    Vogel, Laura J; O'Carroll, Denis M; Edge, Thomas A; Robinson, Clare E

    2016-06-01

    Foreshore beach sands and pore water may act as a reservoir and nonpoint source of fecal indicator bacteria (FIB) to surface waters. This paper presents data collected at a fine sand beach on Lake Huron, Canada over three field events. The data show that foreshore sand erosion as wave height increases results in elevated Escherichia coli concentrations in surface water, as well as depletion of E. coli from the foreshore sand and pore water. E. coli initially attached to foreshore sand rather than initially residing in the pore water was found to be the main contributor to elevated surface water concentrations. Surface water E. coli concentrations were a function of not only wave height (and associated sand erosion) but also the time elapsed since a preceding period of high wave intensity. This finding is important for statistical regression models used to predict beach advisories. While calculations suggest that foreshore sand erosion may be the dominant mechanism for releasing E. coli to surface water during intensified wave conditions at a fine sand beach, comparative characterization of the E. coli distribution at a coarse sand-cobble beach suggests that interstitial pore water flow and discharge may be more important for coarser sand beaches.

  3. Wave climate, sediment supply and the depth of the sand-mud transition: A global survey

    Science.gov (United States)

    George, D.A.; Hill, P.S.

    2008-01-01

    The influences of wave climate and sediment supply on the depths of sand-mud transitions (hSMT) are investigated. Depths of sand-mud transitions (SMT) are based on published granulometric data from surface samples gathered from 14 sites in different wave-dominated coastal environments with fluvial input, including high energy (Columbia, Eel, Russian, San Lorenzo, Copper, and Nepean rivers), moderate energy (Ebro, Nile, Santa Clara, Tseng-wen and Kao-ping rivers), and low energy (Po, Pescara and Tronto rivers) regimes. Geometric mean diameter (GMD) and mud percent are compiled from samples along shore-normal transects, and significant correlation is found between these two textural descriptors. Nominally, the SMT is defined as the transition from GMD > 63????m to 25% mud. This dual definition is applied to the 14 systems, and hSMT is tabulated for each system. Correlation is found between hSMT and the depth at which wave-induced bottom shear stress equals the critical erosion shear stress of the largest mud particles and also between hSMT and significant wave height. Lack of correlation between hSMT and sediment load of nearby rivers indicates either that the influence of sediment supply on depth of the sand-mud transition is small or is not adequately represented in this study. Shelf width and slope do not correlate with residuals from a formalized linear relationship between hSMT and significant wave height. The relationship between hSMT and wave climate is useful for calibration of numerical models of erosion and deposition in wave-dominated coastal environments, for prediction of seabed properties in remote or inaccessible areas, and for reconstruction of paleodepth based on facies changes from sand to mud in ancient rocks. ?? 2008.

  4. Wave-induced ripple development in mixed clay-sand substrates

    Science.gov (United States)

    Wu, Xuxu; Parsons, Daniel; Baas, Jaco H.; Mouazé, Dominique; McLelland, Stuart; Amoudry, Laurent; Eggenhuisen, Jorris; Cartigny, Matthieu; Ruessink, Gerben

    2016-04-01

    This paper reports on a series of experiments that aim to provide a fuller understanding of ripple development within clay-sand mixture substrates under oscillatory flow conditions. The work was conducted in the Total Environment Simulator at the University of Hull and constituted 6 separate runs, in which 5 runs were conducted under identical sets of regular waves (an additional run was conducted under irregular waves, but is not discussed in present paper). The bed content was systematically varied in its composition ranging from a pure sand bed through to a bed comprising 7.4% clay. A series of state-of-the-art measurements were employed to quantify interactions of near-bed hydrodynamics, sediment transport, and turbulence over rippled beds formed by wave action, during and after, each run. The experimental results demonstrate the significant influence of the amount of cohesive clay materials in the substrate on ripple evolution under waves. Most importantly, addition of clay in the bed dramatically slowed down the rate of ripple development and evolution. The equilibrium time of each run increased exponentially from 30 minutes under the control conditions of a pure sand bed, rising to ~350 minutes for the bed with the highest fraction of clay. The paper discusses the slower ripple growth rates with higher cohesive fractions, via an influence on critical shear, but highlights that the end equilibrium size of ripples is found to be independent of increasing substrate clay fraction. The suspended particles mass (SPM) concentration indicates that clay particles were suspended and winnowed by wave action. Additionally, laser granulometry of the final substrates verified that ripple crests were composed of pure sand layers that were absent at ripple troughs, reflecting a relatively higher winnowing efficiency at wave ripples crest. The winnowing process and its efficiency is inexorably linked to wave ripple development and evolution. The implications of the results

  5. Sand ripples under sea waves. Part 4. Tile ripple formation

    NARCIS (Netherlands)

    Roos, Pieter C.; Blondeaux, P.

    2001-01-01

    We investigate the formation of small-scale three-dimensional bedforms due to interactions of an erodible bed with a sea wave that obliquely approaches the coast, being partially reflected at the beach. In this case the trajectories of fluid particles at the top of the bottom boundary layer are

  6. Sand wave migration predictor based on shape information

    NARCIS (Netherlands)

    Knaapen, M.A.F.

    2005-01-01

    [1] Migration of offshore seabed waves, which endangers the stability of pipelines and communication cables, is hard to measure. The migration rates are small compared to the measurement errors. Here, sandwave migration rates are determined from the change in the crest position deduced from long tim

  7. Coastline sand waves on a low-energy beach at El Puntal spit, Spain: Linear stability analysis

    Science.gov (United States)

    MedellíN, G.; FalquéS, A.; Medina, R.; GonzáLez, M.

    2009-03-01

    Shoreline sand waves of approximately 125-150 m of wavelength and ≈15 m of amplitude in the offshore direction (reached in a few days) are often observed at the west end of El Puntal spit, Santander, Spain. They tend to last for about 2 months and do not show an evident alongshore propagation during that time. Since wave incidence on that beach is typically very oblique, a shoreline linear stability analysis is performed to test whether those sand waves could be generated by shoreline instability. Because of the low-energy wave climate and the steep mean bathymetric profile, the predicted wavelength (100-150 m) and growth time (4-8 days) are much smaller than is typical on open ocean beaches. This provides a unique opportunity to test high-angle wave instability. Thus, the role of the instability on the growth, evolution, and subsequent destruction of the sand waves is examined. A remarkable agreement between predictions and observations regarding the wavelength and growth time is found. Furthermore, by analyzing shoreline instability for a 2 year period where sand waves sometimes occur and sometimes do not, a clear correlation is found between sand wave occurrence and predicted instability growth rate. Intriguingly, results are less satisfactory regarding alongshore migration since the model predicts some migration that is not supported by observations. However, it becomes clear that the instability caused by high-angle waves is crucial for shoreline sand wave formation at El Puntal and should be considered for any future research.

  8. Experimental and theoretical modelling of sand-water-object interaction under nonlinear progressive waves

    Science.gov (United States)

    Testik, Firat Yener

    An experimental and theoretical study has been conducted to obtain a fundamental understanding of the dynamics of the sand, water and a solid object interaction as progressive gravity waves impinge on a sloping beach. Aside from obvious scientific interest, this exceedingly complex physical problem is important for naval applications, related to the behavior of disk/cylindrical shaped objects (mines) in the coastal waters. To address this problem, it was divided into a set of simpler basic problems. To begin, nonlinear progressive waves were investigated experimentally in a wave tank for the case of a rigid (impermeable) sloping bottom. Parameterizations for wave characteristics were proposed and compared with the experiments. In parallel, a numerical wave tank model (NWT) was calibrated using experimental data from a single run, and wave field in the wave tank was simulated numerically for the selected experiments. Subsequently, a layer of sand was placed on the slope and bottom topography evolution processes (ripple and sandbar dynamics, bottom topography relaxation under variable wave forcing, etc.) were investigated experimentally. Models for those processes were developed and verified by experimental measurements. Flow over a circular cylinder placed horizontally on a plane wall was also studied. The far-flow field of the cylinder placed in the wave tank was investigated experimentally and numerical results from the NWT simulations were compared with the experimental data. In the mean time, the near-flow velocity/vorticity field around a short cylinder under steady and oscillatory flow was studied in a towing tank. Horseshoe vortex formation and periodic shedding were documented and explained. With the understanding gained through the aforementioned studies, dynamics and burial/scour around the bottom objects in the wave tank were studied. Possible scenarios on the behavior of the disk-shaped objects were identified and explained. Scour around 3D cylindrical

  9. Large submarine sand waves and gravel lag substrates on Georges Bank off Atlantic Canada

    Science.gov (United States)

    Todd, B.J.; Valentine, Page C.; Harris, Peter T; Baker, E.K.

    2012-01-01

    Georges Bank is a large, shallow, continental shelf feature offshore of New England and Atlantic Canada. The bank is mantled with a veneer of glacial debris transported during the late Pleistocene from continental areas lying to the north. These sediments were reworked by marine processes during postglacial sea-level transgression and continue to be modified by the modern oceanic regime. The surficial geology of the Canadian portion of the bank is a widespread gravel lag overlain in places by well sorted sand occurring as bedforms. The most widespread bedforms are large, mobile, asymmetrical sand waves up to 19 m in height formed through sediment transport by strong tidal-driven and possibly storm-driven currents. Well-defined curvilinear bedform crests up to 15 km long form a complex bifurcating pattern having an overall southwest–northeast strike, which is normal to the direction of the major axis of the semidiurnal tidal current ellipse. Minor fields of immobile, symmetrical sand waves are situated in bathymetric lows. Rare mobile, asymmetrical barchan dunes are lying on the gravel lag in areas of low sand supply. On Georges Bank, the management of resources and habitats requires an understanding of the distribution of substrate types, their surface dynamics and susceptibility to movement, and their associated fauna.

  10. Physical processes around a cuspate foreland:. implications to the evolution and long-term maintenance of a cape-associated shoal

    Science.gov (United States)

    McNinch, Jesse E.; Luettich, Richard A.

    2000-12-01

    Understanding across-margin transport has long been recognized as crucial for wise management of our coastline and shelf waters. Issues related to sewage outfalls, nutrient and pollutant dispersal, carbon export, and shoreline sediment budgets all require an understanding of these processes. Across-margin transport of water and sediment at cuspate foreland headlands has been largely unrecognized, and the processes responsible for this export unappreciated. We examined physical process on Cape Lookout Shoal, a cape-associated shoal on the North Carolina continental shelf, through numerical modeling and field observations of near-bottom currents. The cuspate foreland setting of the northern South Atlantic Bight has been previously characterized as wave-dominated with a principal alongshore directed sediment transport and physical circulation forced by wave and wind-driven currents along the inner and mid-shelf. Our findings instead suggest that a seaward-directed, tidal-driven headland flow many play a significant role in the direction of net sediment transport on the shoal and ultimately its location and long-term maintenance. The shoal's location relative to the promontory-induced residual eddies and the region of active deposition differs from traditionally held ideas on sedimentary processes at headland-related sand banks. In addition, the headland flows may also serve as a first-order mechanism for rapidly exporting nearshore and estuarine waters to the outer-shelf.

  11. Monomoy and its Shoals

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of the report is to show the changes — the shifting of position and growth in volume — of Monomoy and its Shoals during the last century. The discussion...

  12. Winter storm-induced hydrodynamics and morphological response of a shallow transgressive shoal complex: Northern Gulf of Mexico

    Science.gov (United States)

    Siadatmousavi, S. Mostafa; Jose, Felix

    2015-03-01

    Using extended deployments during seasons of low and high discharge from the Atchafalaya River, meteorological, hydrodynamic and bottom boundary layer parameters were monitored from Tiger and Trinity Shoal complex, off Louisiana coast, USA. During winter storms, the surface current speed measured at both shoals exceeded 0.5 m/s and the entire water column followed the prevailing wind direction. The current speed close to the bottom exceeded 0.3 m/s during high energy northerly winds. The mean water level in the shoal complex increased during southerly winds and decreased during northerly winds, such that the difference between wind set-up and set-down exceeded 0.7 m in Tiger Shoal and 0.6 m in Trinity Shoal during high energy frontal passages. The swell height was inversely correlated with mean water level, and increased during pre-frontal phase and decreased during post-frontal phase of winter storms. The sea (short waves) height responded quickly to wind direction and speed; and within a few hours after the wind shifted and blowing from the north, the sea height increased during both deployments. Bimodal wave frequency spectrum was observed during wind veering from southerly to northerly, when both sea and swell intensities were significant. The Tiger Shoal bed sediment texture transformed drastically, from mud to shell and shell hash assemblage, within a period of two weeks during the December 2008 deployment. Backscatter signal intensity from a Pulse Coherent Acoustic Doppler Profiler (PCADP) and its velocity estimates were used to determine the vertical extend and timing of mud resuspension and their eventual flushing out from the shoal environment, when exposed to high energy winter storm passages. The computed time frame for a total transformation of bottom sediment texture (from muddy bottom to shell and shell hash assemblage) was supported by the combined wave and bottom current induced shear stress at shoal bed. The bed samples collected from Tiger Shoal

  13. Geotechnical centrifuge model tests for explosion cratering and propagation laws of blast wave in sand

    Institute of Scientific and Technical Information of China (English)

    Yi-kai FAN; Zu-yu CHEN; Xiang-qian LIANG; Xue-dong ZHANG; Xin HUANG

    2012-01-01

    This paper presents the explosion cratering effects and their propagation laws of blast waves in dry standard sands using a 450 g-t geotechnical centrifuge apparatus.Ten centrifuge model tests were completed with various ranges of explosive mass,burial depth and centrifuge accelerations.Eleven accelerometers were installed to record the acceleration response in sand.The dimensions of the explosion craters were measured after the tests.The results demonstrated that the relationship between the dimensionless parameters of cratering efficiency and gravity scaled yield is a power regression function.Three specific function equations were obtained.The results are in general agreement with those obtained by other studies.A scaling law based on the combination of the r terms was used to fit the results of the ten model tests with a correlation coefficient of 0.931.The relationship can be conveniently used to predict the cratering effects in sand.The results also showed that the peak acceleration is a power increasing function of the acceleration level.An empirical exponent relation between the proportional peak acceleration and distance is proposed.The propagation velocity of blast waves is found to be ranged between 200 and 714 m/s.

  14. Cyclic behavior of sandy shoals on the ebb-tidal deltas of the Wadden Sea

    Science.gov (United States)

    Ridderinkhof, W.; Hoekstra, P.; van der Vegt, M.; de Swart, H. E.

    2016-03-01

    Ebb-tidal deltas are bulges of sand that are located seaward of tidal inlets. Many of these deltas feature shoals that cyclically form and migrate towards the coast. The average period between successive shoals that attach to the coast varies among different inlets. In this study, a quantitative assessment of the cyclic behavior of shoals on the ebb-tidal deltas of the Wadden Sea is presented. Analysis of bathymetric data and Landsat satellite images revealed that at the majority of inlets along the Wadden Sea migrating shoals occur. The average period between succeeding shoals correlates to the tidal prism and has values ranging between 4 and 130 years. A larger tidal prism favors larger periods between successive shoal attachments. However, such a relationship was not found for wide inlets with multiple channels. There is a positive relationship between the frequency with which the shoals attach to the coast and their migration velocity, and a negative relationship between the migration velocity of the shoal and the tidal prism. Finally, the data were too sparse to assess whether the longshore sediment transport has a significant effect on the period between successive shoals that attach to the coasts downdrift of the observed tidal inlets.

  15. Breaking of storm waves on sand and reef zone in the Lesser Antilles Arc

    Science.gov (United States)

    Dorville, Jean-François; Berthelot, Hugues; Zahibo, Narcisse

    2010-05-01

    The most part of the exposed coastal zone of the Lesser Antilles Arc are composed by sand and coral reef. The high frequencies of passage of cyclones near these islands and anticyclone's swell subject them to waves of large amplitude. These waves are 4 to 5 times lager to the normal conditions. The weak slopes observed on these zones are particularly sensitive to this type of waves and cause the process of surfing. The mode of dissipation of these waves influenced the run-up and the floods on the coast. The surf zones are situated in 5 in 20 meters of the line of coast. A displacement of sea water towards the coast line is provoked by the breaking of the waves. These quantities of water are held by the particularly bathymetry of these islands and provoke a raised of the sea level. The propagation of the waves are allowed by the sea elevation in the surf zone In the evaluation of the marine risk in the Lesser Antilles Arc, a model of sea state forecast are developed in the Laboratory of Geosciences and Energy (LaRGE) in the French West Indies and French Guiana University (Guadeloupe , FWI). This forecast model is based on the coupling of several numerical models. WaveWatch III and SWAN are used for the wave propagation on large and small sectors. An ocean circulation model based on POM is used to evaluate the sea current and the sea level. To improve the forecasts on the exposed coast, in the zone included between the surf and swash, the sea elevation induced by the large amplitude wave are particularly studies. The numerical model of wave propagation near the coast SWAN is used to determine the sea state before the surf zone. The dissipation and the breaking of the large amplitude waves are studied with the spectral values give by SWAN and the local conditions (bathymetry, sea level, slope, bottom friction). During the months of November and December 2009, several large amplitude waves, coming from the North Atlantic Ocean, impact the west coast of Guadeloupe. The

  16. Sensitivity of growth characteristics of tidal sand ridges and long bed waves to formulations of bed shear stress, sand transport and tidal forcing: A numerical model study

    Science.gov (United States)

    Yuan, Bing; de Swart, Huib E.; Panadès, Carles

    2016-09-01

    Tidal sand ridges and long bed waves are large-scale bedforms that are observed on continental shelves. They differ in their wavelength and in their orientation with respect to the principal direction of tidal currents. Previous studies indicate that tidal sand ridges appear in areas where tidal currents are above 0.5 m s-1, while long bed waves occur in regions where the maximum tidal current velocity is slightly above the critical velocity for sand erosion and the current is elliptical. An idealized nonlinear numerical model was developed to improve the understanding of the initial formation of these bedforms. The model governs the feedbacks between tidally forced depth-averaged currents and the sandy bed on the outer shelf. The effects of different formulations of bed shear stress and sand transport, tidal ellipticity and different tidal constituents on the characteristics of these bedforms (growth rate, wavelength, orientation of the preferred bedforms) during their initial formation were examined systematically. The results show that the formulations for bed shear stress and slope-induced sand transport are not critical for the initial formation of these bedforms. For tidal sand ridges, under rectilinear tidal currents, increasing the critical bed shear stress for sand erosion decreases the growth rate and the wavelength of the preferred bedforms significantly, while the orientation angle slightly decreases. The dependence of the growth rate, wavelength and the orientation of the preferred bedforms on the tidal ellipticity is non-monotonic. A decrease in tidal frequency results in preferred bedforms with larger wavelength and smaller orientation angle, while their growth rate hardly changes. In the case of joint diurnal and semidiurnal tides, or spring-neap tides, the characteristics of the bedforms are determined by the dominant tidal constituent. For long bed waves, the number of anticyclonically/cyclonically oriented bedforms with respect to the principal

  17. Sand-Mud Sediment Transport induced by tidal currents and wind waves in shallow microtidal basins

    Science.gov (United States)

    Carniello, L.; Defina, A.; D'Alpaos, L.

    2011-12-01

    Field data and mathematical modeling have demonstrated that the morphological evolution of shallow tidal basins is the result of the combined effect of tidal currents and wind waves. Tidal currents, in particular, drive the morphological evolution of shallow tidal systems in proximity of the inlets and within the channel network, whereas in shallow areas tidal current mainly acts enhancing the bottom shear stress due to wind waves and redistributing sediments within the basin. In this study we present a mathematical model for sediment entrainment, transport and deposition due to the combined effect of tidal currents and wind waves. The model is coupled with a hydrodynamic module based on the shallow water equations and with a module for the generation and propagation of wind waves. The sediment transport model describes the sediments by the way of a bi-granular mixtures composed by both cohesive and non-cohesive sediments thus considering the contemporary presence of clay, silt and sand which usually characterizes estuaries and tidal basins. Moreover, the model describes the bed evolution and evaluates the variation of bed sediment composition considering also the transition between cohesive and non-cohesive behavior. Attention is focused on some issues concerning the definition of a reliable initial bed composition and the incipient sediment motion which is treated following a stochastic approach for the bottom shear stress and for the critical shear stress distribution. The model is applied to the Lagoon of Venice (Italy) and the results of different simulations are compared, with good agreement, to a series of turbidity measurements collected inside the lagoon. The application of the model to the present bathymetry of the Venice lagoon allows for a first estimation of the actual net amount of sand and mud flowing through the three inlets and also gives some information on bottom evolution in terms of elevation and composition.

  18. Calibration and validation of a sand model considering the effects of wave-induced principal stress axes rotation

    Institute of Scientific and Technical Information of China (English)

    LIU Peng; WANG Zhongtao; LI Xinzhong; CHAN Andrew

    2015-01-01

    Principal stress axes rotation influences the stress-strain behavior of sand under wave loading. A constitutive model for sand, which considers principal stress orientation and is based on generalized plasticity theory, is proposed. The new model, which employs stress invariants and a discrete memory factor during reloading, is original because it quantifies model parameters using experimental data. Four sets of hollow torsion experiments were conducted to calibrate the parameters and predict the capability of the proposed model, which describes the effects of principal stress orientation on the behavior of sand. The results prove the effectiveness of the proposed calibration method.

  19. Modeling the growth and migration of sandy shoals on ebb-tidal deltas

    NARCIS (Netherlands)

    Ridderinkhof, W.; de Swart, H. E.; van der Vegt, M.; Hoekstra, P.

    2016-01-01

    Coherent sandy shoals that migrate toward the downdrift coast are observed on many ebb-tidal deltas. In this study, processes that cause the growth and migration of shoals on ebb-tidal deltas are identified. Moreover, the effect of the incident wave energy and the tidal prism of an inlet on the migr

  20. Sediment characteristics and provenance of the Taiwan Shoal in the southern Taiwan Strait

    Science.gov (United States)

    Koo, W. S.; Lin, A. T.; Kuo, L. W.; Lee, Y. H.

    2016-12-01

    The Taiwan Shoal in the southern Taiwan Strait exhibits a lobe-shaped shallow water area, with a depth less than around 40 m and an area approximately of 13,000 km2. The Shoal consists of relict sediments remnant from deltaic deposits during the last glacial period and associated with the paleo-Min River. We collected seafloor sediments in and around the Taiwan Shoal to study the sediment characteristics and provenance of the Shoal as well as Taiwanese river sediments to characterize sediment sourced from southern Taiwan. Our results help to understand possible sediment delivery pathways in a source-to-sink context from the southern Taiwan Strait to the northern South China Sea. The method of X-ray diffraction is used to identify mineral compositions for muds and mineral compositions are examined under polarized microscope for sands. Zircon grains are separated from heavy minerals for U-Pb dating in order to understand the sediment source terranes. Sediments of the Taiwan Shoal are mostly tawny-colored, medium to coarse-grained sands with abundant shell fragments and shallow-water benthic foraminifera. Sediments to the south of the Taiwan Shoal and in the outer shelf consist of dark brown-colored and fine-grained sands with rare shell fragments. Siliciclastic compositions of the Taiwan Shoal sediments are mostly quartz. The second abundant composition is rock fragments with more occurrences near the Chinese coastline and the Penghu archipelago. Slate fragments are found to occur near Taiwan, especially in the Penghu Channel area. Clay minerals from the Penghu Channels and south of the Taiwan Shoal are dominated by illite and chlorite with minor smectite and kaolinite. The sediment colors and mineral species are very different for the sediments of the Taiwan Shoal and outer shelf, revealing that these two areas featuring different oceanographic processes and sediment provenance.

  1. Mathematical model of wave transformation over radial sand ridge field on continental shelf of South Yellow Sea

    Directory of Open Access Journals (Sweden)

    Yao-zhong YANG

    2010-03-01

    Full Text Available According to a deformed mild-slope equation derived by Guang-wen Hong and an enhanced numerical method, a wave refraction-diffraction nonlinear mathematical model that takes tidal level change and the high-order bathymetry factor into account has been developed. The deformed mild-slope equation is used to eliminate the restriction of wave length on calculation steps. Using the hard disk to record data during the calculation process, the enhanced numerical method can save computer memory space to a certain extent, so that a large-scale sea area can be calculated with high-resolution grids. This model was applied to wave field integral calculation over a radial sand ridge field in the South Yellow Sea. The results demonstrate some features of the wave field: (1 the wave-height contour lines are arc-shaped near the shore; (2 waves break many times when they propagate toward the shore; (3 wave field characteristics on the northern and southern sides of Huangshayang are different; and (4 the characteristics of wave distribution match the terrain features. The application of this model in the region of the radial sand ridge field suggests that it is a feasible way to analyze wave refraction-diffraction effects under natural sea conditions.

  2. Two-dimensional vertical moisture-pressure dynamics above groundwater waves: Sand flume experiments and modelling

    Science.gov (United States)

    Shoushtari, Seyed Mohammad Hossein Jazayeri; Cartwright, Nick; Perrochet, Pierre; Nielsen, Peter

    2017-01-01

    This paper presents a new laboratory dataset on the moisture-pressure relationship above a dispersive groundwater wave in a two-dimensional vertical unconfined sand flume aquifer driven by simple harmonic forcing. A total of five experiments were conducted in which all experimental parameters were kept constant except for the oscillation period, which ranged from 268 s to 2449 s between tests. Moisture content and suction head sensor pairings were co-located at two locations in the unsaturated zone both approximately 0.2 m above the mean watertable elevation and respectively 0.3 m and 0.75 m from the driving head boundary. For all oscillation periods except for the shortest (T = 268s), the formation of a hysteretic moisture-pressure scanning loop was observed. Consistent with the decay of the saturated zone groundwater wave, the size of the observed moisture-pressure scanning loops decayed with increasing distance landward and the decay rate is larger for the shorter oscillation periods. At the shortest period (T = 268s), the observed moisture-pressure relationship was observed to be non-hysteretic but with a capillary capacity that differs from that of the static equilibrium wetting and drying curves. This finding is consistent with observations from existing one-dimensional vertical sand column experiments. The relative damping of the moisture content with distance landward is higher than that for the suction head consistent with the fact that transmission of pressure through a porous medium occurs more readily than mass transfer. This is further supported by the fact that observed phase lags for the unsaturated zone variables (i.e. suction head and moisture content) relative to the driving head are greater than the saturated zone variables (i.e. piezometric head). Harmonic analysis of the data reveals no observable generation of higher harmonics in either moisture or pressure despite the strongly non-linear relationship between the two. In addition, a phase lag

  3. Experimental study on impact-induced seismic wave propagating through quartz sand simulating asteroid regolith

    Science.gov (United States)

    Matsue, Kazuma; Arakawa, Masahiko; Yasui, Minami; Matsumoto, Rie; Tsujido, Sayaka; Takano, Shota; Hasegawa, Sunao

    2015-08-01

    Introduction: Recent spacecraft surveys clarified that asteroid surfaces were covered with regolith made of boulders and pebbles such as that found on the asteroid Itokawa. It was also found that surface morphologies of asteroids formed on the regolith layer were modified. For example, the high-resolution images of the asteroid Eros revealed the evidence of the downslope movement of the regolith layer, then it could cause the degradation and the erasure of small impact crater. One possible process to explain these observations is the regolith layer collapse caused by seismic vibration after projectile impacts. The impact-induced seismic wave might be an important physical process affecting the morphology change of regolith layer on asteroid surfaces. Therefore, it is significant for us to know the relationship between the impact energy and the impact-induced seismic wave. So in this study, we carried out impact cratering experiments in order to observe the seismic wave propagating through the target far from the impact crater.Experimental method: Impact cratering experiments were conducted by using a single stage vertical gas gun set at Kobe Univ and a two-stage vertical gas gun set at ISAS. We used quartz sands with the particle diameter of 500μm, and the bulk density of 1.48g/cm3. The projectile was a ball made of polycarbonate with the diameter of 4.75mm and aluminum, titan, zirconia, stainless steel, cupper, tungsten carbide projectile with the diameter of 2mm. These projectiles were launched at the impact velocity from 0.2 to 7km/s. The target was set in a vacuum chamber evacuated below 10 Pa. We measured the seismic wave by using a piezoelectric uniaxial accelerometer.Result: The impact-induced seismic wave was measured to show a large single peak and found to attenuate with the propagation distance. The maximum acceleration of the seismic wave was recognized to have a good relationship with the normalized distance x/R, where x is the propagation distance

  4. Electromagnetic wave attenuation due to the charged particles in dust&sand (DUSA) storms

    Science.gov (United States)

    Dou, X. Q.; Xie, L.

    2017-07-01

    In this paper, we calculated the attenuation of the electromagnetic waves (EMWs) propagating through the dust&sand (DUSA) storms using the predicting model based on Mie theory, in which the charges carried on the DUSA particles, the ambient relative humidity (RH) and the particle size distribution are considered simultaneously. It can be found that the charges carried on the DUSA particles and the RH can change the value of the absorption and scattering efficiency, but they can't change the domain attenuation mechanism caused by the DUSA storms in the EMWs frequency regions (3 GHz, 4 GHz), (8 GHz, 40 GHz) and (75 GHz, 100 GHz). Whatever the DUSA storms are formed by equal-size particles or the mixed-size particles, the charge carried on the particle surface and the RH have a significant impact on the attenuation caused by the DUSA storms, and the change ratio of the attenuation caused by the charge or RH depends on the particle size. By the comparison of the calculated attenuation with the measured one, we found that the charges carried on the particles and the RH will be important factors to affect the attenuation of the EMWs.

  5. Wave-induced flow and its influence on ridge erosion and channel deposition in Lanshayang channel of radial sand ridges

    Institute of Scientific and Technical Information of China (English)

    陈可峰; 安翔; 陆培东; 张玮; 徐卓

    2014-01-01

    Very limited modeling studies were available of the wave-induced current under the complex hydrodynamic conditions in the South Yellow Sea Radial Sand Ridge area (SYSRSR). Partly it is due to the difficulties in estimating the influence of the wave-induced current in this area. In this study, a coupled 3-D storm-surge-wave model is built. In this model, the time-dependent varying Collins coefficient with the water level method (TCL) are used. The wave-flow environment in the Lanshayang Channel (LSYC) during the “Winnie” typhoon is successfully represented by this model. According to the modelling results, at a high water level (HWL), the wave-induced current similar to the long-shore current will emerge in the shallow area of the ridges, and has two different motion trends correlated with the morphological characteristics of the ridges. The wave-induced current velocity could be as strong as 1 m/s, which is at the same magnitude as the tidal current. This result is verified by the bathymetric changes in the LSYC during the “Matsa” typhoon. Thus, the wave-induced current may be one of the driven force of the ridge erosion and channel deposition in the SYSRSR. These conclusions will help to further study the mechanism of the ridge erosion and channel deposition in the SYSRSR.

  6. Shoaling Analysis at Brazos Island, Harbor Inlet, Texas

    Science.gov (United States)

    2015-10-01

    Channel Shoaling Project, waves, currents, water levels, bathymetry, and sediment samples are being collected in and around BIH. These data will be... Texas by Ernest R. Smith, Tahirih C. Lackey, David B. King, and Richard Styles PURPOSE: This Coastal and Hydraulics Engineering Technical Note...compared to recent events. INTRODUCTION: Brazos Island Harbor (also called Brazos Santiago Pass) is located on the lower Gulf of Mexico Texas coast

  7. Transduction on Kadanoff Sand Pile Model Avalanches, Application to Wave Pattern Emergence

    CERN Document Server

    Perrot, Kévin

    2011-01-01

    Sand pile models are dynamical systems describing the evolution from $N$ stacked grains to a stable configuration. It uses local rules to depict grain moves and iterate it until reaching a fixed configuration from which no rule can be applied. The main interest of sand piles relies in their {\\em Self Organized Criticality} (SOC), the property that a small perturbation | adding some sand grains | on a fixed configuration has uncontrolled consequences on the system, involving an arbitrary number of grain fall. Physicists L. Kadanoff {\\em et al} inspire KSPM, a model presenting a sharp SOC behavior, extending the well known {\\em Sand Pile Model}. In KSPM($D$), we start from a pile of $N$ stacked grains and apply the rule: $D-1$ grains can fall from column $i$ onto the $D-1$ adjacent columns to the right if the difference of height between columns $i$ and $i+1$ is greater or equal to $D$. This paper develops a formal background for the study of KSPM fixed points. This background, resumed in a finite state word tr...

  8. Modelling of sand transport under wave-generated sheet flows with a RANS diffusion model

    NARCIS (Netherlands)

    Hassan, Wael; Ribberink, Jan S.

    2010-01-01

    A 1DV-RANS diffusion model is used to study sand transport processes in oscillatory flat-bed/sheet flow conditions. The central aim is the verification of the model with laboratory data and to identify processes controlling the magnitude and direction (‘onshore’/‘offshore’) of the net time-averaged

  9. Infragravity-wave dynamics in shallow water : energy dissipation and role in sand suspension and transport

    NARCIS (Netherlands)

    de Bakker, A.T.M.

    2016-01-01

    Infragravity waves (20-200 s) receive their energy from sea-swell waves (2-20 s), and are thought to be important to beach erosion during storms, when they can reach up to several meters in height. Numerous studies have observed that on sandy beaches infragravity waves can lose a large part of their

  10. Infragravity-wave dynamics in shallow water : energy dissipation and role in sand suspension and transport

    NARCIS (Netherlands)

    de Bakker, A.T.M.

    2016-01-01

    Infragravity waves (20-200 s) receive their energy from sea-swell waves (2-20 s), and are thought to be important to beach erosion during storms, when they can reach up to several meters in height. Numerous studies have observed that on sandy beaches infragravity waves can lose a large part of their

  11. Character of shell beds flanking Herod Point shoal, southeastern Long Island Sound, New York

    Science.gov (United States)

    Poppe, L.J.; Williams, S.J.; Babb, Ivar G.

    2011-01-01

    High biogenic productivity, strong tidal currents, shoal topography, and short transport distances combine to favor shell-bed formation along the lower flanks of a cape-associated shoal off Herod Point on Long Island, New York. This shell bed has a densely packed, clast-supported fabric composed largely of undegraded surf clam (Spisula solidissima) valves. It is widest along the central part of the western flank of the shoal where topographic gradients are steep and a stronger flood tide results in residual flow. The bed is narrower and thinner toward the landward margins where currents are too weak to transport larger valves and topographic gradients are gentle, limiting bed-load transport mechanisms by which the shells are concentrated. Reconnaissance mapping off Roanoke Point suggests that shell beds are also present at the other cape-associated shoals off northeastern Long Island, where relatively similar geomorphic and oceanographic conditions exist. These shell beds are important to the Long Island Sound ecosystem because they provide complex benthic habitats of rough and hard substrates at the boundary between the muddy basin floor and mobile sand of the shoals. ?? 2011, the Coastal Education & Research Foundation (CERF).

  12. Wave Height Distribution for Spilling Waves in and outside the Surf Zone

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The wave characteristics affecting coastal sediment transport include wave height, wave period and breaking wave direction. Wave height is a critical factor in determining the amount of sediment transport in the coastal area. The force of sediment transport is much more intense under breaking waves than under non-breaking waves. Breaking waves exhibit various patterns, principally depending on the incident wave steepness and the beach slope. Based on the equations of conservation of mass, momentum and energy, a theoretical model for wave deformation in and outside the surf zone was obtained, which is used to calculate the wave shoaling, wave set-up and setdown and wave height distributions in and outside the surf zone. The analysis and comparison were made about the breaking point location and the wave height decay caused by the wave breaking and the bottom friction. Flume experiments relating to the spilling wave height distribution across the surf zone were conducted to verify the theoretical model. Advanced wave maker, data sampling devices and data processing system were utilized in the flume experiments with a slope covered by sands of different diameters to facilitate the observation and research on the wave transformation and breaking. The agreement between the theoretical and experimental results is good.

  13. Numerical modeling of wave overwash on low-crested sand barriers

    NARCIS (Netherlands)

    Tuan, T.Q.; Verhagen, H.J.; Visser, P.J.; Stive, M.

    2006-01-01

    For management of coastal breaching hazards it is critical to be able to assess the potential of coastal barrier breaching as a result of wave actions during storm surges (wave overwash). This phenomenon is known as the breach initiation phase; the mechanisms behind this are not very well understood

  14. The Use of GPR in Delineating an Iron Sand Boundary and the Determination of Its Electromagnetic Wave Velocity: A Case Study in Jepara, Central Java

    Directory of Open Access Journals (Sweden)

    S. Bijaksana

    2005-11-01

    Full Text Available Exploring the vertical extent of iron sand deposit is challenging as conventional geophysical methods (electrical resistivity, geomagnetic, and seismic refraction are inappropriate and unsuccessful in delineating the iron sand deposit from the bedrock. Ground-penetrating radar (GPR offers a solution to the above problem as radar is not affected negatively by the physical properties of iron sand. In the year 2003, a RAMAC’s GPR survey was carried out in the coast of Bayuran in the Regency of Jepara, Central Java to map the distribution of sub-bottom iron sand. The sand is highly magnetic. The survey used 100 MHz antennas. The survey is also complimented by a novel method in determining the electromagnetic (EM wave velocity of iron sand. Combination of reflection profiling and CMP sounding was deployed. Results of CMP sounding were processed using CMP-semblance analysis that produces the RMS velocity in velocity-time spectra. The RMS velocity is then converted to interval velocity using Dix’s formula and is found to be about 135 mm/ns. Meanwhile, combination of magnetic susceptibility, relative permittivity, and dissipation factors produces radiowaves velocity of iron sand as a function of frequency. The velocities of radiowaves estimated from laboratory match that estimated from CMP analysis.

  15. Resonant interaction of acoustic waves with subaqueous bedforms: Sand dunes in the South China Sea.

    Science.gov (United States)

    Chiu, Linus Y S; Chang, Andrea Y Y; Reeder, D Benjamin

    2015-12-01

    The large subaqueous sand dunes in the South China Sea are expected to produce the coupling of energy between acoustic normal modes. In this letter, resonant interaction between acoustic propagating modes and subaqueous bedforms are numerically investigated as a function of bedform wavelength, acoustic frequency and bedform packet length. The results demonstrate that bedform wavelength impacts acoustic mode coupling behavior, with the principal transfer of energy occurring between acoustic modes whose eigenvalue difference is equal to the peak value in the bedform wavenumber spectrum. The observed effect of wavelength is greater than that of acoustic frequency and bedform packet length.

  16. Bathymetric mapping of submarine sand waves using multiangle sun glitter imagery: a case of the Taiwan Banks with ASTER stereo imagery

    Science.gov (United States)

    Zhang, Hua-guo; Yang, Kang; Lou, Xiu-lin; Li, Dong-ling; Shi, Ai-qin; Fu, Bin

    2015-01-01

    Submarine sand waves are visible in optical sun glitter remote sensing images and multiangle observations can provide valuable information. We present a method for bathymetric mapping of submarine sand waves using multiangle sun glitter information from Advanced Spaceborne Thermal Emission and Reflection Radiometer stereo imagery. Based on a multiangle image geometry model and a sun glitter radiance transfer model, sea surface roughness is derived using multiangle sun glitter images. These results are then used for water depth inversions based on the Alpers-Hennings model, supported by a few true depth data points (sounding data). Case study results show that the inversion and true depths match well, with high-correlation coefficients and root-mean-square errors from 1.45 to 2.46 m, and relative errors from 5.48% to 8.12%. The proposed method has some advantages over previous methods in that it requires fewer true depth data points, it does not require environmental parameters or knowledge of sand-wave morphology, and it is relatively simple to operate. On this basis, we conclude that this method is effective in mapping submarine sand waves and we anticipate that it will also be applicable to other similar topography types.

  17. Interactions between shoal size and conformity in guppy social foraging

    OpenAIRE

    Day, R.L.; MacDonald, T; Brown, C.; Laland, K.N.; Reader, S.M.

    2001-01-01

    Previous experimental studies have established that shoaling fish forage more effectively in large than small groups. We investigated how shoal size affects the foraging efficiency of laboratory populations of the guppy, Poecilia reticulata, exposed to different foraging tasks. Experiment 1 confirmed the prediction that in open water the first fish and focal fish of larger shoals locate food faster than in smaller shoals. However, a second experiment, in which shoals of fish were required to ...

  18. Modelling of wave propagation over a submerged sand bar using SWASH

    Digital Repository Service at National Institute of Oceanography (India)

    Jishad, M.; Vu, T.T.T.; JayaKumar, S.

    for the case of a moderately high wave energy, due to significant variations in the bed morphology, the model under-performed towards the later part of the simulation However, incorporating a modified bathymetry considering the variation in the bed morphology...

  19. Numerical modelling of wave overwash at low-crested sand barriers

    NARCIS (Netherlands)

    Tuan, T.Q.

    2005-01-01

    In overwash beaches, response of a barrier profile as a whole to storm wave attacks can be distinguished into seaward and landward parts that are associated with two respective across-shore driving processes i.e. surge erosion, and overwash. Modeling of overwash relies heavily on the specification o

  20. Airborne Lidar Bathymetry: The SHOALS System

    Science.gov (United States)

    2016-05-09

    competitive with conventional survey methods. Surveying 16 km2 per hour and collecting soundings every 4 m. SHOALS remotely measures water depths using state...1998). SHOALS standard products include a digital text file of project depths and elevations, contour maps, channel and structure cross-sections...6000N digital survey fathometer). This system meets IHO charting requirements and was extensively used by NOM to meet their charting needs. During Mt

  1. Patch behaviour and predictability properties of modelled finite-amplitude sand ridges on the inner shelf

    Directory of Open Access Journals (Sweden)

    N. C. Vis-Star

    2008-12-01

    Full Text Available The long-term evolution of shoreface-connected sand ridges is investigated with a nonlinear spectral model which governs the dynamics of waves, currents, sediment transport and the bed level on the inner shelf. Wave variables are calculated with a shoaling-refraction model instead of using a parameterisation. The spectral model describes the time evolution of amplitudes of known eigenmodes of the linearised system. Bottom pattern formation occurs if the transverse bottom slope of the inner shelf, β, exceeds a critical value βc. For fixed model parameters the sensitivity of the properties of modelled sand ridges to changes in the number (N−1 of resolved subharmonics (of the initially fastest growing mode is investigated. For any N the model shows the growth and subsequent saturation of the height of the sand ridges. The saturation time scale is several thousands of years, which suggests that observed sand ridges have not reached their saturated stage yet. The migration speed of the ridges and the average longshore spacing between successive crests in the saturated state differ from those in the initial state. Analysis of the potential energy balance of the ridges reveals that bed slope-induced sediment transport is crucial for the saturation process. In the transient stage the shoreface-connected ridges occur in patches. The overall characteristics of the bedforms (saturation time, final maximum height, average longshore spacing, migration speed hardly vary with N. However, individual time series of modal amplitudes and bottom patterns strongly depend on N, thereby implying that the detailed evolution of sand ridges can only be predicted over a limited time interval. Additional experiments show that the critical bed slope βc increases with larger offshore angles of wave incidence, larger offshore wave heights and longer wave periods, and that the corresponding maximum height of the ridges

  2. Ultrasound Wave Attenuation of Grain Refined High – Zinc Aluminium Sand-cast Alloys

    Directory of Open Access Journals (Sweden)

    Krajewski W.K.

    2015-06-01

    Full Text Available The paper presents results of measuring attenuation coefficient of the Al-20 wt.% Zn alloy (AlZn20 inoculated with different grain refiners. During experiments the melted alloys were doped with Al-Ti3-C0.15 refining master alloy. Basing on measurements performed by Krautkramer USLT2000 device with 1MHz ultrasound wave frequency it was stated that grain refinement reduces the attenuation coefficient by about 20-25%. However, the examined alloys can be still classified as the high-damping ones of attenuation greater than 150 dB/m.

  3. 76 FR 19122 - Record of Decision (ROD) for Authorizing the Use of Outer Continental Shelf (OCS) Sand Resources...

    Science.gov (United States)

    2011-04-06

    ... the Use of Outer Continental Shelf (OCS) Sand Resources in National Aeronautics and Space... Availability (NOA) of the Record of Decision. SUMMARY: BOEMRE has issued a ROD to authorize the use of OCS sand... for the purpose of making sand available from a shoal on the OCS for placement on the beach in...

  4. 77 FR 24980 - Record of Decision for Authorizing the Use of Outer Continental Shelf (OCS) Sand Resources in the...

    Science.gov (United States)

    2012-04-26

    ... (OCS) Sand Resources in the Martin County, Florida Hurricane Storm Damage Reduction Project AGENCY... Decision. SUMMARY: BOEM has issued a Record of Decision (ROD) to authorize the use of OCS sand resources by... agreement for the purpose of making sand available from a shoal on the OCS for placement on the beach...

  5. Nutritional state influences shoaling preference for familiars.

    Science.gov (United States)

    Frommen, Joachim G; Luz, Corinna; Bakker, Theo C M

    2007-01-01

    Preferences for grouping with familiar individuals are shown in many animal species, including the three-spined stickleback (Gasterosteus aculeatus). Shoaling with familiars is advantageous because of more precise anti-predator behaviours or more stable dominance hierarchies. Additionally, associations with familiar individuals facilitate the evolution of altruistic behaviour. Thus, in situations of increased competition one might expect an increased preference for familiar fish. We gave single juvenile sticklebacks of different nutritional state the choice between shoals composed either of familiar or unfamiliar individuals. Satiated fish preferred to shoal with familiar individuals. A comparative analysis of 8 stickleback studies with 15 different tests using familiars showed that all tests gave similar results, i.e. sticklebacks of all age classes preferred to shoal with familiars in a non-sexual context. In contrast, hungry test fish did not prefer to shoal with familiar fish, but even showed a preference for the unfamiliar group. Because sticklebacks use early-life familiarity to recognize kin, the results suggest the avoidance of competition with relatives. To our knowledge, this is the first study showing an impact of nutritional state on social interactions with familiar individuals.

  6. Interactions between shoal size and conformity in guppy social foraging

    NARCIS (Netherlands)

    Day, R.L.; Macdonald, T.; Brown, C.; Laland, K.N.; Reader, S.M.

    2001-01-01

    Previous experimental studies have established that shoaling fish forage more effectively in large than small groups. We investigated how shoal size affects the foraging efficiency of laboratory populations of the guppy, Poecilia reticulata, exposed to different foraging tasks. Experiment 1

  7. Effect of Low Energy Waves on the Accumulation and Transport of Fecal Indicator Bacteria in Sand and Pore Water at Freshwater Beaches.

    Science.gov (United States)

    Wu, Ming Zhi; O'Carroll, Denis M; Vogel, Laura J; Robinson, Clare E

    2017-02-24

    Elevated fecal indicator bacteria (FIB) in beach sand and pore water represent an important nonpoint source of contamination to surface waters. This study examines the physical processes governing the accumulation and distribution of FIB in a beach aquifer. Field data indicate E. coli and enterococci can be transported 1 and 2 m, respectively, below the water table. Data were used to calibrate a numerical model whereby FIB are delivered to a beach aquifer by wave-induced infiltration across the beach face. Simulations indicate FIB rapidly accumulate in a beach aquifer with FIB primarily associated with sand rather than freely residing in the pore water. Simulated transport of E. coli in a beach aquifer is complex and does not correlate with conservative tracer transport. Beaches with higher wave-induced infiltration rate and vertical infiltration velocity (i.e., beaches with higher beach slope and wave height, and lower terrestrial groundwater discharge) had greater E. coli accumulation and E. coli was transported deeper below the beach face. For certain beach conditions, the amount of FIB accumulated in sand over 5-6 days was found to be sufficient to trigger a beach advisory if eroded to surface water.

  8. Priori knowledge based a bathymetry assessment method using the sun glitter imagery:a case study of sand waves on the Taiwan Banks

    Institute of Scientific and Technical Information of China (English)

    SHAO Hao; LI Yan; LI Li

    2014-01-01

    High resolution optical satellite imageries containing the sun glitter, similar to synthetic aperture radar (SAR) imageries, are useful in identifying and mapping of bottom topography in shallow waters. The errors in the previous studies are corrected, and a method for mapping submarine bottom topography is devel-oped using the sun glitter satellite imagery. The method is established on the basis of empirical description of a sand wave using an equation with two unknowns named r and k . In order to determine r and k , a“trial and error”approach is introduced and testified by a case study on the Taiwan Banks using an ASTER imagery. The results show that the inversed water depths match well with the sounding water depths. The a-greement between the inversed results and the in situ measurements is about 78%by comparing 371 points. Moreover, this method has the advantage in keeping the original appearance of a sand wave, especially in positions around the sand wave crest. The fine agreement indicates that the imaging model is flexible and the approach developed is feasible.

  9. Data Decision Analysis: Project Shoal

    Energy Technology Data Exchange (ETDEWEB)

    Forsgren, Frank; Pohll, Greg; Tracy, John

    1999-01-01

    The purpose of this study was to determine the most appropriate field activities in terms of reducing the uncertainty in the groundwater flow and transport model at the Project Shoal area. The data decision analysis relied on well-known tools of statistics and uncertainty analysis. This procedure identified nine parameters that were deemed uncertain. These included effective porosity, hydraulic head, surface recharge, hydraulic conductivity, fracture correlation scale, fracture orientation, dip angle, dissolution rate of radionuclides from the puddle glass, and the retardation coefficient, which describes the sorption characteristics. The parameter uncertainty was described by assigning prior distributions for each of these parameters. Next, the various field activities were identified that would provide additional information on these parameters. Each of the field activities was evaluated by an expert panel to estimate posterior distribution of the parameters assuming a field activity was performed. The posterior distributions describe the ability of the field activity to estimate the true value of the nine parameters. Monte Carlo techniques were used to determine the current uncertainty, the reduction of uncertainty if a single parameter was known with certainty, and the reduction of uncertainty expected from each field activity on the model predictions. The mean breakthrough time to the downgradient land withdrawal boundary and the peak concentration at the control boundary were used to evaluate the uncertainty reduction. The radionuclide 137Cs was used as the reference solute, as its migration is dependent on all of the parameters. The results indicate that the current uncertainty of the model yields a 95 percent confidence interval between 42 and 1,412 years for the mean breakthrough time and an 18 order-of-magnitude range in peak concentration. The uncertainty in effective porosity and recharge dominates the uncertainty in the model predictions, while the

  10. 基于微观尺度的砂土剪切波速度%Shear wave velocity in sand based on microscopic size

    Institute of Scientific and Technical Information of China (English)

    黄博; 夏唐代; 周新民; 刘志军

    2016-01-01

    运用宏观等效与微观接触理论相结合的方法研究砂土剪切波速度。在宏观上将砂土看作均匀连续各向同性介质,在微观尺度上假设砂土为等效球体半径相等、材料性质相同、随机堆积的固体颗粒的集合体,结合颗粒接触理论,引入颗粒形状修正系数,推导出砂土的等效剪切模量和宏观剪切波速度公式。通过定量计算进行参数分析。研究结果表明:孔隙比、砂土颗粒弹性模量、埋深和颗粒形状修正系数对砂土剪切波速的影响显著;有效内摩擦角、砂土颗粒泊松比、砂土密度和与配位数有关的常数对剪切波速影响较小。将理论计算结果与实测值进行对比,吻合较好,验证了本方法的可行性与正确性。%Based on the macroscopic equivalent model and microscopic contact theories, the shear wave velocity was studied. Considered as a kind of homogeneous, continuous and isotropic media macroscopically, the sand was assumed microscopically as an aggregate of randomly packed uniform equivalent spheres with the same material properties. Then, the formulas of the equivalent shear modulus and shear wave velocity in sand were derived by using particle contact theory and by introducing the correcting coefficient of the granule shape. The main influencing factors were analyzed through quantitative calculations. The results indicate that the shear wave velocity is mainly influenced by void ratio, elastic modulus of sand granule, burial depth and the correcting coefficient of the granule shape, while it is hardly influenced by inner friction angle, Poisson’s ratio of sand granule, density of the sand and the constant connected with the coordination number. Through comparison, the calculation results using the present formulas agree well with measured data so as to verify the validity of the proposed method.

  11. Kin assortment in juvenile shoals in wild guppy populations.

    Science.gov (United States)

    Piyapong, C; Butlin, R K; Faria, J J; Scruton, K J; Wang, J; Krause, J

    2011-05-01

    Grouping provides many potential benefits to individuals in terms of foraging and anti-predator protection. However, it has been suggested that individuals could gain additional benefits in terms of indirect fitness by grouping with kin. Surprisingly, the genetic composition of wild fish shoals and the importance of kin-associated shoaling remain poorly understood. The Trinidadian guppy (Poecilia reticulata) has life history traits that might promote kin structure of shoals such as internal fertilisation and small brood size in contrast to many other fish species. Even though previous studies did not find any indication of kin structure in shoals of adult guppies, it is possible that related juveniles remain together in shoals, partly because of lower mobility and because the advantages of kin association may change with age. Using 10 microsatellite markers, we conducted a genetic analysis on 40 shoals from four populations. Pair-wise relatedness was inferred using a modified version of the software package COLONY and permutation tests were conducted to test the hypothesis that kin occur together in juvenile shoals more often than expected by chance. The frequency of sib dyads among juveniles within shoals was significantly larger than that between shoals in two high predation populations but not in two low predation populations. This finding contributes to the understanding of factors underlying shoal composition and highlights the potential of recent methodological advances for detecting such relationships.

  12. CMS-Wave

    Science.gov (United States)

    2014-10-27

    2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE CMS -Wave 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...Program CMS -Wave CMS -Wave is a two-dimensional spectral wind-wave generation and transformation model that employs a forward-marching, finite...difference method to solve the wave action conservation equation. Capabilities of CMS -Wave include wave shoaling, refraction, diffraction, reflection

  13. Numerical modelling of nearshore wave transformation

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Nayak, B.U.; SanilKumar, V.

    A software has been developed for numerical refraction study based on finite amplitude wave theories. Wave attenuation due to shoaling, bottom friction, bottom percolation and viscous dissipation has also been incorporated. The software...

  14. Fontainebleau Sand

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    2006-01-01

    The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand.......The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand....

  15. Eustatic and far-field tectonic control on the development of an intra-platform carbonate-shoal complex: upper tongue of the Tanglewood Member, Upper Ordovician Lexington Limestone, central Kentucky, U.S.A.

    Science.gov (United States)

    Koirala, Dibya Raj; Ettensohn, Frank R.; Clepper, Marta L.

    2016-11-01

    The Lexington or Trenton Limestone is an Upper Ordovician (Chatfieldian-Edenian; upper Sandbian-lower Katian), temperate-water unit, averaging about 60-m thick, that was deposited in relatively shallow waters across the Lexington Platform in east-central United States during the Taconian Orogeny. Lexington/Trenton shallow-water deposition ended across most of the platform in late Chatfieldian time and from that point deepened upward into the more shale-rich Clays Ferry, Point Pleasant and Kope formations due to apparent sea-level rise. In central Kentucky, however, deposition of the Lexington Limestone continued into early Edenian time and includes up to 50 m of additional coarse calcarenites and calcirudites at the top, which form the Tanglewood buildup and reflect locally regressive conditions, apparently related to local structural uplift. Consequently, in central Kentucky, the Lexington is more than 100-m thick, and Lexington deposition on the buildup continued into early Edenian time as an intra-platform shoal complex that tongues out into deeper-water units in all directions. In an attempt to understand how this shoal complex developed, we examined the last major body of coarse skeletal sands in the central Kentucky Lexington Limestone, the upper tongue of the Tanglewood Member, a 12-m-thick succession of fossiliferous calcarenite and calcirudite that occurs across an area of 5200 km2 near the center of the Lexington Platform. Although relatively homogeneous, the upper Tanglewood is divisible into five, small-scale, fining-upward, sequence-like cycles, which contain prominent, widespread deformed horizons. Facies analysis indicates that four lithofacies, which reflect distinct depositional environments, comprise the sequences across the shoal complex. Lithofacies were correlated across the shoal complex by integrating cyclicity and widespread deformed horizons in order to delineate the locations of major depositional environments. Facies analysis shows that

  16. Characteristics and mechanisms of cardiopulmonary injury caused by mine blasts in shoals: a randomized controlled study in a rabbit model.

    Directory of Open Access Journals (Sweden)

    Gengfen Han

    Full Text Available BACKGROUND: Because the characteristics of blast waves in water are different from those in air and because kinetic energy is liberated by a pressure wave at the water-air interface, thoracic injuries from mine blasts in shoals may be serious. The aim of the present study was to investigate the characteristics and mechanisms of cardiopulmonary injury caused by mine blasts in shoals. METHODS: To study the characteristics of cardiopulmonary injury, 56 animals were divided randomly into three experimental groups (12 animals in the sham group, 22 animals in the land group and 22 animals in the shoal group. To examine the biomechanics of injury, 20 animals were divided randomly into the land group and the shoal group. In the experimental model, the water surface was at the level of the rabbit's xiphoid process, and paper electric detonators (600 mg RDX were used to simulate mines. Electrocardiography and echocardiography were conducted, and arterial blood gases, serum levels of cardiac troponin I and creatine kinase-MB and other physiologic parameters were measured over a 12-hour period after detonation. Pressures in the thorax and abdomen and the acceleration of the thorax were measured. CONCLUSION: The results indicate that severe cardiopulmonary injury and dysfunction occur following exposure to mine blasts in shoals. Therefore, the mechanisms of cardiopulmonary injury may result from shear waves that produce strain at the water-air interface. Another mechanism of injury includes the propagation of the shock wave from the planta to the thorax, which causes a much higher peak overpressure in the abdomen than in the thorax; as a result, the abdominal organs and diaphragm are thrust into the thorax, damaging the lungs and heart.

  17. Stress and temperature distributions of individual particles in a shock wave propagating through dry and wet sand mixtures

    Science.gov (United States)

    Schumaker, Merit G.; Kennedy, Gregory; Thadhani, Naresh; Hankin, Markos; Stewart, Sarah T.; Borg, John P.

    2017-01-01

    Determining stress and temperature distributions of dynamically compacted particles is of interest to the geophysical and astrological research communities. However, the researcher cannot easily observe particle interactions during a planar shock experiment. By using mesoscale simulations, we can unravel granular particle interactions. Unlike homogenous materials, the averaged Hugoniot state for heterogeneous granular materials differs from the individual stress and temperature states of particles during a shock event. From planar shock experiments for dry and water-saturated Oklahoma sand, we constructed simulations using Sandia National Laboratory code known as CTH and then compared these simulated results to the experimental results. This document compares and presents stress and temperature distributions from simulations, with a discussion on the difference between Hugoniot measurements and distribution peaks for dry and water-saturated sand.

  18. Geophysical and Geotechnical Determination of Sand Resources on the Florida Atlantic Continental Shelf: Preliminary Results

    Science.gov (United States)

    Finkl, C. W.; Andrews, J. L.; Suthard, B. C.; Robertson, W.

    2007-12-01

    The State of Florida is committed to maintaining beaches to sustain beach width and protect coastal infrastructure. Nearshore sand resources must be identified and cataloged for potential beach nourishment projects in response to sea-level rise and increased tropical storm activity. Given the vast length of Florida coastline, application of a variety of remote sensing techniques are required for measuring large areas in a short amount of time. The study area encompasses a shelf area of about 2,053,220 ha (20,532 km2) from Miami to the Georgia State line (about 653 km shoreline length) and extends up to 27 km offshore to about the 45 m isobath offshore Jacksonville. The continental shelf along the east coast of the Florida peninsula contains a wide range of seafloor environments that lie above the Florida-Hatteras Slope on the shoreface and inner, middle, and outer shelf floors. This study used Airborne Laser Bathymetry (ALB), 3D digital terrain models based on reformatted NOAA bathymetric data, sidescan sonar, and seismic reflection profiling to map seafloor geomorphological conditions that range from coralline-algal reef systems to drowned karst, submerged paleo shorelines (drowned beach ridge plains), and buried paleo channels. Seatruthing of morphosedimentary features is achieved via jetprobe and vibracore surveys in the study of inter-reefal sand troughs, ebb-tidal deltas, transverse bars, shoals, sand waves, ridges, and banks. Preliminary results, which visualize seafloor topography as color-ramped morphoforms, indicate the presence of sedimentary deposits that may constitute viable sand resources for shore protection in the form of beach renourishment. Use of ALB and reformatted NOAA bathymetric data in the form of 3D terrain models permits classification of submarine landform topologies that was heretofore not possible using isobaths. The combination of multiple remote sensing methods showed the spatial distribution of morphosedimentary features and provided

  19. Speleothems and Sand Castles

    Science.gov (United States)

    Hance, Trevor; Befus, Kevin

    2015-01-01

    The idea of building sand castles evokes images of lazy summer days at the beach, listening to waves crash, enjoying salty breezes, and just unplugging for a while to let our inner child explore the wonderful natural toys beneath our feet. The idea of exploring caves might evoke feelings and images of claustrophobia or pioneers and Native…

  20. Daily variation in the shoaling behavior of zebrafish Danio rerio

    Institute of Scientific and Technical Information of China (English)

    Timothy PACIOREK; Scott MCROBERT

    2012-01-01

    Shoaling behavior provides numerous fitness benefits for fish,including enhanced access to mates,increased success in foraging and protection from predators.We were interested in determining whether shoaling intensity differed throughout the day.To do this we kept adult zebrafish Danio rerio in different lighting conditions for 10 days:“Normal” (12:12LD,lights on at 0800 hrs),“Reverse” (12:12LD,lights on at 2000 hrs),DD,or LL,and then observed the shoaling behavior at different times during the day.Our findings suggest that daily variations exist in shoaling behavior,with mean shoaling times for fish from the ‘normal' group being the lowest at the mid-point of the dark phase in the fish's subjective day (00:00 hrs),then rising significantly throughout the day,reaching their highest intensity at 20:00 lrs (lights out).Fish from the “reverse” LD cycle (lights on at 20:00 hrs) showed differences in the mean shoaling times at different times of day,but did not show a gradual increase in shoaling throughout their subjective day.Fish from the DD and LL groups did not show significant differences in the mean shoaling values at different times of day,suggesting that the differences observed in LD fish may not represent circadian rhythms.Therefore,these results demonstrate the existence of daily variations in the shoaling behavior of fish and suggest that environmental cues in the form of light/dark cycles play an important role in regulating these variations [Current Zoology 58 (1):129-137,2012].

  1. Daily variation in the shoaling behavior of zebrafish Danio rerio

    Directory of Open Access Journals (Sweden)

    Timothy PACIOREK, Scott MCROBERT

    2012-02-01

    Full Text Available Shoaling behavior provides numerous fitness benefits for fish, including enhanced access to mates, increased success in foraging and protection from predators. We were interested in determining whether shoaling intensity differed throughout the day. To do this we kept adult zebrafish Danio rerio in different lighting conditions for 10 days: “Normal” (12:12LD, lights on at 0800 hrs, “Reverse” (12:12LD, lights on at 2000 hrs, DD, or LL, and then observed the shoaling behavior at different times during the day. Our findings suggest that daily variations exist in shoaling behavior, with mean shoaling times for fish from the ‘normal’ group being the lowest at the mid–point of the dark phase in the fish’s subjective day (00:00 hrs, then rising significantly throughout the day, reaching their highest intensity at 20:00 hrs (lights out. Fish from the “reverse” LD cycle (lights on at 20:00 hrs showed differences in the mean shoaling times at different times of day, but did not show a gradual increase in shoaling throughout their subjective day. Fish from the DD and LL groups did not show significant differences in the mean shoaling values at different times of day, suggesting that the differences observed in LD fish may not represent circadian rhythms. Therefore, these results demonstrate the existence of daily variations in the shoaling behavior of fish and suggest that environmental cues in the form of light/dark cycles play an important role in regulating these variations [Current Zoology 58 (1: 129–137, 2012].

  2. Long-term morphological response to dredging including cut-across-shoal in a tidal channel-shoal system

    Science.gov (United States)

    Wang, Yu-Hai; Wang, Chong-Hao; Tang, Li-Qun; Liu, Da-Bin; Guo, Chuan-Sheng; Liu, Chun-Jing; Zhao, Hui-Ming

    2014-12-01

    This study examines long-term channel-shoal stability in the Tieshan Bay, which is located on the southwest coast of China. A large-scale channel-shoal system has historically existed in the outer Tieshan Bay. A navigation waterway is initiated by cutting and dredging a mid-channel shoal to supply coal to a power plant on the middle coast of the Tieshan Bay. Dredging of the access channel to the Tieshan Port was conducted in two stages followed by land reclamation. It is thus of practical meaning to explore how the channel-shoal system will evolve in long term afterwards. This study uses the process-based finite-volume coastal ocean model (FVCOM) to investigate long-term (centennial) morphological evolution of the channel-shoal system. After well calibration of hydrodynamics and sediment transport, the model forecasts morphodynamic evolution in hundred years. The simulations show that continuous erosion in tidal channels and accretion over shoals and intertidal flats occur. However, the cutting and access channels will be subjected to long-term siltation. A secondary channel indicating the reorientation of the access channel will emerge, and a localized channel-ridge system at the junction of the major channels will be formed. The overall erosion/accretion pattern demonstrates the combined effect of bottom friction and advective sediment transport processes to be responsible for the channel-shoal formation. Dredging of the tidal channels will stimulate the stability of the channel-shoal pattern. It suggests that the navigation waterway should be set up following the long-term morphological evolution of the channel-shoal system at a design stage and maintenance dredging volume might thus be minimized.

  3. LEGACY - EOP CRITTERCAM Deployments on French Frigate Shoals monk seals

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — CRITTERCAMs, were deployed on a 42 monk seals at French Frigate Shoals Hawaii. Sixty nine hours of video comprised of 3192 recording segments collected at...

  4. Hawaii Abandoned Vessel Inventory, French Frigate Shoals, NWHI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for French Frigate Shoals. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of...

  5. CRED REA Algal Assessment, Stingray Shoals 2003 (NODC Accession 0010352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Twelve quadrats were haphazardly collected at 2 sites at Stingray Shoals in the Commonwealth of the Northern Mariana Islands in August and September, 2003 from the...

  6. Sediment contaminant assessment for Shoal Creek, Lawrence County, Tennessee

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Sediment samples were collected from ten locations along Shoal Creek and analyzed for l9 metals and 20 organochlorine compounds. For the organic analyses,...

  7. Validation Analysis of the Shoal Groundwater Flow and Transport Model

    Energy Technology Data Exchange (ETDEWEB)

    A. Hassan; J. Chapman

    2008-11-01

    Environmental restoration at the Shoal underground nuclear test is following a process prescribed by a Federal Facility Agreement and Consent Order (FFACO) between the U.S. Department of Energy, the U.S. Department of Defense, and the State of Nevada. Characterization of the site included two stages of well drilling and testing in 1996 and 1999, and development and revision of numerical models of groundwater flow and radionuclide transport. Agreement on a contaminant boundary for the site and a corrective action plan was reached in 2006. Later that same year, three wells were installed for the purposes of model validation and site monitoring. The FFACO prescribes a five-year proof-of-concept period for demonstrating that the site groundwater model is capable of producing meaningful results with an acceptable level of uncertainty. The corrective action plan specifies a rigorous seven step validation process. The accepted groundwater model is evaluated using that process in light of the newly acquired data. The conceptual model of ground water flow for the Project Shoal Area considers groundwater flow through the fractured granite aquifer comprising the Sand Springs Range. Water enters the system by the infiltration of precipitation directly on the surface of the mountain range. Groundwater leaves the granite aquifer by flowing into alluvial deposits in the adjacent basins of Fourmile Flat and Fairview Valley. A groundwater divide is interpreted as coinciding with the western portion of the Sand Springs Range, west of the underground nuclear test, preventing flow from the test into Fourmile Flat. A very low conductivity shear zone east of the nuclear test roughly parallels the divide. The presence of these lateral boundaries, coupled with a regional discharge area to the northeast, is interpreted in the model as causing groundwater from the site to flow in a northeastward direction into Fairview Valley. Steady-state flow conditions are assumed given the absence of

  8. Channel-shoal morphodynamics in response to distinct hydrodynamic drivers at the outer Weser estuary

    Science.gov (United States)

    Herrling, Gerald; Benninghoff, Markus; Zorndt, Anna; Winter, Christian

    2017-04-01

    The interaction of tidal, wave and wind forces primarily governs the morphodynamics of intertidal channel-shoal systems. Typical morphological changes comprise tidal channel meandering and/or migration with related shoal erosion or accretion. These intertidal flat systems are likely to response to accelerated sea level rise and to potential changes in storm frequency and direction. The aim of the ongoing research project is an evaluation of outer estuarine channel-shoal dynamics by combining the analysis of morphological monitoring data with high-resolution morphodynamic modelling. A focus is set on their evolution in reaction to different hydrodynamic forcings like tides, wind driven currents, waves under fair-weather and high energy conditions, and variable upstream discharges. As an example the Outer Weser region was chosen, and a tidal channel system serves as a reference site: Availability of almost annual bathymetrical observations of an approx. 10 km long tidal channel (Fedderwarder Priel) and its morphological development largely independent from maintenance dredging of the main Weser navigational channel make this tributary an ideal study area. The numerical modelling system Delft3D (Deltares) is applied to run real-time annual scenario simulations aiming to evaluate and to differentiate the morphological responses to distinct hydrodynamic drivers. A comprehensive morphological analysis of available observations at the FWP showed that the channel migration trends and directions are persistent at particular channel bends and meanders for the considered period of 14 years. Migration trends and directions are well reproduced by one-year model simulations. Morphodynamic modelling is applied to interpolate between observations and relate sediment dynamics to different forcing scenarios in the outer Weser estuary as a whole and at the scale of local tributary channels and flats.

  9. Sea-level rise and coastal groundwater inundation and shoaling at select sites in California, USA

    Science.gov (United States)

    Hoover, Daniel J.; Odigie, Kingsley; Swarzenski, Peter W.; Barnard, Patrick

    2016-01-01

    Study regionThe study region spans coastal California, USA, and focuses on three primary sites: Arcata, Stinson Beach, and Malibu Lagoon.Study focus1 m and 2 m sea-level rise (SLR) projections were used to assess vulnerability to SLR-driven groundwater emergence and shoaling at select low-lying, coastal sites in California. Separate and combined inundation scenarios for SLR and groundwater emergence were developed using digital elevation models of study site topography and groundwater surfaces constructed from well data or published groundwater level contours.New hydrological insights for the regionSLR impacts are a serious concern in coastal California which has a long (∼1800 km) and populous coastline. Information on the possible importance of SLR-driven groundwater inundation in California is limited. In this study, the potential for SLR-driven groundwater inundation at three sites (Arcata, Stinson Beach, and Malibu Lagoon) was investigated under 1 m and 2 m SLR scenarios. These sites provide insight into the vulnerability of Northern California coastal plains, coastal developments built on beach sand or sand spits, and developed areas around coastal lagoons associated with seasonal streams and berms. Northern California coastal plains with abundant shallow groundwater likely will see significant and widespread groundwater emergence, while impacts along the much drier central and southern California coast may be less severe due to the absence of shallow groundwater in many areas. Vulnerability analysis is hampered by the lack of data on shallow coastal aquifers, which commonly are not studied because they are not suitable for domestic or agricultural use. Shallow saline aquifers may be present in many areas along coastal California, which would dramatically increase vulnerability to SLR-driven groundwater emergence and shoaling. Improved understanding of the extent and response of California coastal aquifers to SLR will help in preparing for mitigation

  10. Sediment resuspension and the generation of intermediate nepheloid layers by shoaling internal bores

    Science.gov (United States)

    Masunaga, Eiji; Arthur, Robert S.; Fringer, Oliver B.; Yamazaki, Hidekatsu

    2017-06-01

    Numerical simulations of sediment resuspension due to shoaling internal bores are performed with a nonhydrostatic model, SUNTANS. Results show strong sediment resuspension induced by internal bores and a turbidity layer intruding offshore in the interior of the water column, known as an intermediate nepheloid layer (INL). Sediment resuspension processes and INLs reproduced in the model are in good agreement with observational data from Otuschi Bay, Japan. The formation of INLs by shoaling internal waves is explained as follows: (1) strong receding currents due to a previous run-up bore cause sediment resuspension along the slope, (2) the interaction of the receding currents and a subsequent run-up bore induce horizontal flow convergence and strong upward currents, (3) the upward currents lift the suspended sediments into the interior of the water column, (4) the run-up bore intrudes below the suspended sediments and forms an INL within the pycnocline. Sediment resuspension processes are also investigated for various internal Iribarren number conditions. The internal Iribarren number represents the ratio of the topographic slope to the internal wave steepness. In low internal Iribarren number conditions, strong currents near the bottom result in sediment resuspension and INL formation. In high internal Iribarren number conditions, sediment resuspension is weak, and INLs do not form.

  11. Sand Resources, Regional Geology, and Coastal Processes of the Chandeleur Islands Coastal System: an Evaluation of the Breton National Wildlife Refuge

    Science.gov (United States)

    Lavoie, Dawn

    2009-01-01

    Monkey Bayou at the southern end of the Chandeleur Islands. Numerical simulation of waves and sediment transport supports the geophysical results and indicates that vast areas of the lower shoreface are affected and are undergoing erosion during storm events, that there is little or no fair weather mechanism to rework material into the littoral system, and that as a result, there is a net loss of sediment from the system. Lidar surveys revealed that the island chain immediately after Hurricane Katrina lost about 84 percent of its area and about 92 percent of its prestorm volume. Marsh platforms that supported the islands' sand prior to the storm were reduced in width by more than one-half. Repeated lidar surveys document that in places the shoreline has retreated about 100 m under the relatively low-energy waves since Hurricanes Katrina and Rita; however, this retreat is nonuniform. Recent high-resolution geophysical surveys of the sea floor and subsurface within 5-6 km of the Chandeleur Islands during 2006 and 2007 show that, in addition to the sand that is rebuilding portions of the island chain, a large volume of sand is contained in Hewes Point, in an extensive subtidal spit platform that has formed at the northern end of the Chandeleur Islands. Hewes Point appears to be the depositional terminus of the alongshore transport system. In the southern Chandeleurs, sand is being deposited in a broad tabular deposit near Breton Island called the southern offshore sand sheet. These two depocenters account for approximately 70 percent of the estimated sediment volume located in potential borrow sites. An additional large potential source of sand for restoration lies in the St. Bernard Shoals, which are estimated to contain approximately 200 ? 106 m3 of sand. Successful restoration planning for the Breton National Wildlife Refuge should mimic the natural processes of early stages of barrier island evolution including lateral transport to the flanks of the island chain

  12. Numerical simulation of wind wave surface profiles with tuned phase spectra

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    to nonlinear waves with vertical and horizontal asymmetries especially in the case of breaking and shoaling waves. Hence, the inverse method of computing the surface profile from a known autospectrum using transformed (tuned) phase spectrum with coupling...

  13. Sand supply to beaches

    Science.gov (United States)

    Aagaard, Troels

    2017-04-01

    In most cases, beaches and dunes are built by sand that has been transported onshore from the shoreface. While this has been known for a long time, we are still not able to quantitatively predict onshore sediment transport and sand supply to beaches. Sediment transport processes operating during brief, high-energy stormy conditions - when beaches erode and sand moves offshore - are fairly well known and they can be modelled with a reasonable degree of confidence. However, the slower onshore sand transport leading to beach recovery under low-to-moderate energy conditions - and the reason why beaches and dunes exist in the first place - is not yet well understood. This severely limits our capability to understand and predict coastal behaviour on long time scales, for example in response to changing sea level or wave conditions. This paper will discuss issues and recent developments in sediment transport measurement and prediction on the lower and upper shoreface and into the swash zone. The focus will be on the integration and upscaling of small-scale deterministic process measurements into parametric models that may increase modelling capabilities of coastal behaviour on larger temporal and spatial scales.

  14. Approximate equations at breaking for nearshore wave transformation coefficients

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Nayak, B.U.; SanilKumar, V.

    Based on small amplitude wave theory approximate equations are evaluated for determining the coefficients of shoaling, refraction, bottom friction, bottom percolation and viscous dissipation at breaking. The results obtainEd. by these equations...

  15. Beach monitoring project Sand Key Phase II Beach nourishment program (North Redington Beach and Redington Shores) Post-Nourishment Report Part II Offshore Profiles and Wave Data

    OpenAIRE

    1989-01-01

    This study presents the third post-nourishment survey (January 1989) results for the Sand Key Phase II beach nourishment project carried out in June, 1988. The monitoring program to this beach nourishment project is a joint effort between the University of South Florida and University of Florida. The field surveys include a total of 26 profiles, encompassing approximately 3 miles of shoreline extending from DNR R-96 to R-1ll. The total calculated volume loss of sand in the n...

  16. Possible return of Acropora cervicornis at Pulaski Shoal, Dry Tortugas National Park, Florida

    Science.gov (United States)

    Lidz, Barbara H.; Zawada, David G.

    2013-01-01

    Seabed classification is essential to assessing environmental associations and physical status in coral reef ecosystems. At Pulaski Shoal in Dry Tortugas National Park, Florida, nearly continuous underwater-image coverage was acquired in 15.5 hours in 2009 along 70.2 km of transect lines spanning ~0.2 km2. The Along-Track Reef-Imaging System (ATRIS), a boat-based, high-speed, digital imaging system, was used. ATRIS-derived benthic classes were merged with a QuickBird satellite image to create a habitat map that defines areas of senile coral reef, carbonate sand, seagrasses, and coral rubble. This atypical approach of starting with extensive, high-resolution in situ imagery and extrapolating between transect lines using satellite imagery leverages the strengths of each remote-sensing modality. The ATRIS images also captured the spatial distribution of two species once common on now-degraded Florida-Caribbean coral reefs: the stony staghorn coral Acropora cervicornis, a designated threatened species, and the long-spined urchin Diadema antillarum. This article documents the utility of ATRIS imagery for quantifying number and estimating age of A. cervicornis colonies (n = 400, age range, 5–11 y) since the severe hypothermic die-off in the Dry Tortugas in 1976–77. This study is also the first to document the largest number of new colonies of A. cervicornis tabulated in an area of the park where coral-monitoring stations maintained by the Fish and Wildlife Research Institute have not been established. The elevated numbers provide an updated baseline for tracking revival of this species at Pulaski Shoal.

  17. Sex differences in a shoaling-boldness behavioral syndrome, but no link with aggression.

    Science.gov (United States)

    Way, Gregory P; Kiesel, Alexis L; Ruhl, Nathan; Snekser, Jennifer L; McRobert, Scott P

    2015-04-01

    A behavioral syndrome is observed in a population when specific behaviors overlap at the individual level in different contexts. Here, we explore boldness and aggression personality spectra, the repeatability of shoaling, and possible associated correlations between the behaviors in a population of lab-reared zebrafish (Danio rerio). Our findings describe a sex-specific boldness-shoaling behavioral syndrome, as a link between boldness and shoaling behaviors is detected. The results indicate that bold males are likely to have a stronger shoaling propensity than shy males for unfamiliar conspecifics. Conversely, bold females are more likely to shoal than shy females, but only when presented with heterospecific individuals. Additionally, aggression does not correlate with boldness or shoaling propensity for either sex. A positive relationship between boldness and shoaling that differs by sex is contrary to most of the present literature, but could help to explain population dynamics and may also have evolutionary implications.

  18. Near-bed hydrodynamics and turbulence below a large-scale plunging breaking wave over a mobile barred bed profile

    Science.gov (United States)

    van der Zanden, J.; van der A, D. A.; Hurther, D.; Cáceres, I.; O'Donoghue, T.; Ribberink, J. S.

    2016-08-01

    Detailed measurements are presented of velocities and turbulence under a large-scale regular plunging breaking wave in a wave flume. Measurements were obtained at 12 cross-shore locations around a mobile medium-sand breaker bar. They focused particularly on the dynamics of the wave bottom boundary layer (WBL) and near-bed turbulent kinetic energy (TKE), measured with an Acoustic Concentration and Velocity Profiler (ACVP). The breaking process and outer flow hydrodynamics are in agreement with previous laboratory and field observations of plunging waves, including a strong undertow in the bar trough region. The WBL thickness matches with previous studies at locations offshore from the bar crest, but it increases near the breaking-wave plunge point. This relates possibly to breaking-induced TKE or to the diverging flow at the shoreward slope of the bar. Outer flow TKE is dominated by wave breaking and exhibits strong spatial variation with largest TKE above the breaker bar crest. Below the plunge point, breaking-induced turbulence invades the WBL during both crest and trough half cycle. This results in an increase in the time-averaged TKE in the WBL (with a factor 3) and an increase in peak onshore and offshore near-bed Reynolds stresses (with a factor 2) from shoaling to breaking region. A fraction of locally produced TKE is advected offshore over a distance of a few meters to shoaling locations during the wave trough phase, and travels back onshore during the crest half cycle. The results imply that breaking-induced turbulence, for large-scale conditions, may significantly affect near-bed sediment transport processes.

  19. Sands styrke

    DEFF Research Database (Denmark)

    Jacobsen, H. Moust; Jørgensen, Mogens B.; Poulsen, H. Serup

    1975-01-01

    På grundlag af triaxialforsøg med D=7 og 20 cm og varierende højde på løse og faste lejringer af Blokhussand kan effekten af varierende højde-breddeforhold og spændingsniveau samt skalaeffekten bestemmes. Ved sammenligning med pladeforsøg med overfladelast op til 8 t/m2 kan den almindelige fremga...... fremgangsmåde ved bæreevneberegninger på sand undersøges....

  20. Effect of State of Stress on Velocity of Low-Amplitude Shear Waves Propagating along Principal Stress Directions in Dry Sand.

    Science.gov (United States)

    1982-03-01

    overconsolidation ratio, k = function of soil plasticity (k = 0 for sands), e = void ratio, Pa = atmospheric pressure in units of Gax* max K1 27 n slope of log G max...on soil Plasticity Index, w 37 j = elastic Poisson’s ratio, r 2 F(e) = function of void ratio (F(e) = 0.3 + 0.7e2), n = slope of log G - log a0...OCR = overconsolidation ratio, k = factor related to soil plasticity (for sand, k = 0), Pa = atmospheric pressure in same units as Gm e = void ratio

  1. Experimental study on influence of particle roughness on shear wave velocity of sand%砂土颗粒粗糙度对剪切波速影响的试验研究

    Institute of Scientific and Technical Information of China (English)

    刘瑜; 夏唐代

    2011-01-01

    6 sand samples are made by use of Fujian standard sand, Hangzhou sand and man-made quartz sand, respectively, with each sample composed of the single sand particle in diameter.The average particle roughness of every sample and the shear wave velocities (Vs) of each sample in different porosities are obtained by electron microscope and bender element testing equipment.The analytic results indicate that Vs is greatly influenced by the particle roughness, and the magnitude of Vs decreases with the increase of the particle roughness.The roughness coefficient is introduced to deduce the formula of Vs by means of the researches on micro fabrics and constitutive relations of granular materials, elastic contact of rough particles, etc.Moreover, the results drawn from the present method are compared with the measured data, and the calculating method of the roughness coefficient for low sands is obtained.In addition, the relationship between the roughness coefficient and the stress is discussed.%将福建标准砂、杭州黄砂和人工石英砂制备成6个砂样,每个砂样只由一种粒径的砂颗粒组成,从每个砂样中选取一定数量的颗粒进行电镜扫描并分析砂样的颗粒平均粗糙度,用弯曲元测试仪测试各砂样在不同孔隙比下的剪切波速(Vs).对比分析说明颗粒粗糙度对Vs的影响显著,Vs随着颗粒粗糙度的增大而减小.引入粗糙度修正系数,在散粒体介质细观组构与本构关系、弹性粗糙颗粒接触等研究的基础上推导了砂土Vs计算公式.将计算结果与试验实测值进行对比,得到了浅层砂土的粗糙度修正系数的计算方法,讨论了粗糙度修正系数随应力大小的变化趋势.

  2. Tar sand

    Energy Technology Data Exchange (ETDEWEB)

    McLendon, T.R.; Bartke, T.C.

    1990-01-01

    Research on tar sand is briefly discussed. The research program supported by the US Department of Energy (DOE) includes a variety of surface extraction schemes. The University of Utah has process development units (PDU) employing fluidized bed, hot, water-assisted, and fluidized-bed/heat-pipe, coupled combustor technology. Considerable process variable test data have been gathered on these systems: (1) a rotary kiln unit has been built recently; (2) solvent extraction processing is being examined; and (3) an advanced hydrogenation upgrading scheme (hydropyrolysis) has been developed. The University of Arkansas, in collaboration with Diversified Petroleum, Inc., has been working on a fatty acid, solvent extraction process. Oleic acid is the solvent/surfactant. Solvent is recovered by adjusting processing fluid concentrations to separate without expensive operations. Western Research Institute has a PDU-scale scheme called the Recycle Oil Pyrolysis and Extraction (ROPE) process, which combines solvent (hot recycle bitumen) and pyrolytic extraction. 14 refs., 19 figs.

  3. It's in the sand

    OpenAIRE

    Mitchell, Clive

    2016-01-01

    Sand is sand isn’t it? Sand gets everywhere but rather than a nuisance it is a valuable, high-purity raw material. Clive Mitchell, Industrial Minerals Specialist at the British Geological Survey (BGS), talks us through what sand is, what it can be used for and how to find it. His exploration of sand takes us from the deserts of Arabia to the damp sand pits of Mansfield!

  4. Booming Sand Dunes

    Science.gov (United States)

    Vriend, Nathalie

    "Booming" sand dunes are able to produce low-frequency sound that resembles a pure note from a music instrument. The sound has a dominant audible frequency (70-105 Hz) and several higher harmonics and may be heard from far distances away. A natural or induced avalanche from a slip face of the booming dune triggers the emission that may last for several minutes. There are various references in travel literature to the phenomenon, but to date no scientific explanation covered all field observations. This thesis introduces a new physical model that describes the phenomenon of booming dunes. The waveguide model explains the selection of the booming frequency and the amplification of the sound in terms of constructive interference in a confined geometry. The frequency of the booming is a direct function of the dimensions and velocities in the waveguide. The higher harmonics are related to the higher modes of propagation in the waveguide. The experimental validation includes quantitative field research at the booming dunes of the Mojave Desert and Death Valley National Park. Microphone and geophone recordings of the acoustic and seismic emission show a variation of booming frequency in space and time. The analysis of the sensor data quantifies wave propagation characteristics such as speed, dispersion, and nonlinear effects and allows the distinction between the source mechanism of the booming and the booming itself. The migration of sand dunes results from a complicated interplay between dune building, wind regime, and precipitation. The morphological and morphodynamical characteristics of two field locations are analyzed with various geophysical techniques. Ground-penetrating radar images the subsurface structure of the dunes and reveal a natural, internal layering that is directly related to the history of dune migration. The seismic velocity increases abruptly with depth and gradually increases with downhill position due to compaction. Sand sampling shows local

  5. Industrial sand and gravel

    Science.gov (United States)

    Dolley, T.P.

    2013-01-01

    Domestic production of industrial sand and gravel in 2012 was about 49.5 Mt (55 million st), increasing 13 percent compared with that of 2011. Some important end uses for industrial sand and gravel include abrasives, filtration, foundry, glassmaking, hydraulic fracturing sand (frac sand) and silicon metal applications.

  6. Sand swimming lizard: sandfish

    CERN Document Server

    Maladen, Ryan D; Kamor, Adam; Goldman, Daniel I

    2009-01-01

    We use high-speed x-ray imaging to reveal how a small (~10cm) desert dwelling lizard, the sandfish (Scincus scincus), swims within a granular medium [1]. On the surface, the lizard uses a standard diagonal gait, but once below the surface, the organism no longer uses limbs for propulsion. Instead it propagates a large amplitude single period sinusoidal traveling wave down its body and tail to propel itself at speeds up to ~1.5 body-length/sec. Motivated by these experiments we study a numerical model of the sandfish as it swims within a validated soft sphere Molecular Dynamics granular media simulation. We use this model as a tool to understand dynamics like flow fields and forces generated as the animal swims within the granular media. [1] Maladen, R.D. and Ding, Y. and Li, C. and Goldman, D.I., Undulatory Swimming in Sand: Subsurface Locomotion of the Sandfish Lizard, Science, 325, 314, 2009

  7. Eastern Scheldt Sand, Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Andersen, A. T; Madsen, E. B.; Schaarup-Jensen, A. L.

    The present data report contains data from 13 drained triaxial tests, performed on two different sand types in the Soil Mechanics Laboratory at Aalborg University in March, 1997. Two tests have been performed on Baskarp Sand No. 15, which has already ken extensively tested in the Soil Mechanics...... Laboratory. The remaining 11 triaxial tests have ben performed on Eastern Scheldt Sand, which is a material not yet investigated at the Soil Mechanics Laboratory. In the first pari of this data report, the characteristics of the two sand types in question will be presented. Next, a description...

  8. Locomotory transition from water to sand and its effects on undulatory kinematics in sand lances (Ammodytidae).

    Science.gov (United States)

    Gidmark, Nicholas J; Strother, James A; Horton, Jaquan M; Summers, Adam P; Brainerd, Elizabeth L

    2011-02-15

    Sand lances, fishes in the genus Ammodytes, exhibit a peculiar burrowing behavior in which they appear to swim rapidly into the substrate. They use posteriorly propagated undulations of the body to move in both water, a Newtonian fluid, and in sand, a non-Newtonian, granular substrate. In typical aquatic limbless locomotion, undulations of the body push against water, which flows because it is incapable of supporting the static stresses exerted by the animal, thus the undulations move in world space (slipping wave locomotion). In typical terrestrial limbless locomotion, these undulations push against substrate irregularities and move relatively little in world space (non-slipping wave locomotion). We used standard and X-ray video to determine the roles of slipping wave and non-slipping wave locomotion during burrowing in sand lances. We find that sand lances in water use slipping wave locomotion, similar to most aquatic undulators, but switch to non-slipping waves once they burrow. We identify a progression of three stages in the burrowing process: first, aquatic undulations similar to typical anguilliform locomotion (but without head yaw) push the head into the sand; second, more pronounced undulations of the aquatic portion of the body push most of the animal below ground; third, the remaining above-ground portion of the body ceases undulation and the subterranean portion takes over, transitioning to non-slipping wave locomotion. We find no evidence that sand lances use their body motions to fluidize the sand. Instead, as soon as enough of the body is underground, they undergo a kinematic shift and locomote like terrestrial limbless vertebrates.

  9. Runup of tsunami waves in U-shaped bays

    CERN Document Server

    Didenkulova, Ira

    2010-01-01

    The problem of tsunami wave shoaling and runup in U-shaped bays (such as fjords) and underwater canyons is studied in the framework of shallow water theory. The wave shoaling in bays, when the depth varies smoothly along the channel axis, is studied with the use of asymptotic approach. In this case a weak reflection provides significant shoaling effects. The existence of traveling (progressive) waves, propagating in bays, when the water depth changes significantly along the channel axis, is studied. It is shown that traveling waves do exist for certain bay bathymetry configurations and may propagate over large distances without reflection. The tsunami runup in such bays is significantly larger than for a plane beach.

  10. Influence green sand system by core sand additions

    OpenAIRE

    N. Špirutová; J. Beňo; V. Bednářová; J. Kříž; M. Kandrnál

    2012-01-01

    Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron) are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this co...

  11. Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Borup, Marianne; Hedegaard, Jette

    The Soil Mechanics Laboratory has started performing tests with a new sand, Baskarp No 15. Baskarp No 15 is a graded sand from Sweden. The shapes of the largest grains are round, while the small grains have sharp edges. The main part of of Baskarp No 15 is quarts, but it also contains feldspar...... and biotit. Mainly the sand will be used for tests concerning the development og the theory of building up pore pressure in sand, L. B. Ibsen 1993....

  12. Lund Sand No 0

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Jakobsen, Finn Rosendal

    During the last 15 years the Geotechnical Engineering Group (GEG) at Aalborg University has performed triaxial tests with a sand called Lund No 0. Lund No 0 is a graded sand from a gravel pit near Horsens in Denmark. For the classification of the sand the following tests have been performed: Sieve...

  13. From schooling to shoaling: patterns of collective motion in zebrafish (Danio rerio.

    Directory of Open Access Journals (Sweden)

    Noam Miller

    Full Text Available Animal groups on the move can take different configurations. For example, groups of fish can either be 'shoals' or 'schools': shoals are simply aggregations of individuals; schools are shoals exhibiting polarized, synchronized motion. Here we demonstrate that polarization distributions of groups of zebrafish (Danio rerio are bimodal, showing two distinct modes of collective motion corresponding to the definitions of shoaling and schooling. Other features of the group's motion also vary consistently between the two modes: zebrafish schools are faster and less dense than zebrafish shoals. Habituation to an environment can also alter the proportion of time zebrafish groups spend schooling or shoaling. Models of collective motion suggest that the degree and stability of group polarization increases with the group's density. Examining zebrafish groups of different sizes from 5 to 50, we show that larger groups are less polarized than smaller groups. Decreased fearfulness in larger groups may function similarly to habituation, causing them to spend more time shoaling than schooling, contrary to most models' predictions.

  14. Strength and sintering effects at ejection of explosively driven sand

    Science.gov (United States)

    Resnyansky, A. D.; Weckert, S. A.

    2014-05-01

    A description of the response of sand to extreme loads is very important for the evaluation of the sand ejecta impact effects on various targets. Sand is a complex material to simulate because of its porosity where the inter-phase equilibrium is hard to achieve under transient shock wave loading. A previously developed two-phase model with strength has been implemented in CTH and applied to sand. The shock response of the sand, including the Hugoniot abnormality known from the literature for highly porous silica, is adequately described with the material model. The sand unloading effects appearing as the ejecta are observed in the present work using dynamic flash X-ray of an aluminium target plate loaded by limestone sand ejecta from the detonation of a buried high explosive charge. The CTH modelling results compared with the flash X-ray images have demonstrated good agreement, particularly, in the description of momentum transfer to the target.

  15. Petrophysical Analysis of Oil Sand in Athabasca

    Science.gov (United States)

    cheong, S.; Lee, H.

    2013-12-01

    Oil sands are the major unconventional energy sources which have great reserves in Alberta, Canada. Recovery techniques such as CSS (Cyclic Steam Stimulation) and SAGD (Steam Assisted Gravity Drainage) enabled to develop deeper bitumen about several hundred meter depth. Before applying CSS and SAGD, reservoir heterogeneity of mud barriers or shale breccias should be clarified to establish injection and production wells successfully. We conducted the integrated petro-physical analysis for oil sands deposits in Athabasca by correlating well logs with seismic data. From 33 well logs and 3D seismic, we have made P-wave impedance by recursive inversion. Target formations of our analysis were the top of Wabiskaw member. Using inverted impedance and multi-attributes, porosity volume was derived at a target depth. Porosity of time slice 375 ms ranged 20 ~ 40 % stretching porous sand body from NE to SW direction. Characteristics of porosity distribution may be useful to design optimum oil sands recovery in Athabasca.

  16. Sand transport processes in the surf and swash zones

    NARCIS (Netherlands)

    Zanden, van der Joep

    2016-01-01

    Long-term predictions of beach morphology using numerical models contribute to cost-effective coastal protection strategies. The physics of sand transport in the wave breaking region and the swash zone are not fully understood, leading to poor predictive capability of existing sand transport models

  17. LEARNING ABOUT THE OCEANS FROM SAND

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    As a young geophysicist in the 1980s, Rob Holman attended a conference in San Francisco that included a field trip to a beach. Dr Holman, who grew up inland, stared at the ocean, assessing the strengths of the waves. But when he looked around, everyone else was studying the sand.

  18. Wave

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many t...

  19. CRED REA Coral Population Parameters at French Frigate Shoals, Northwestern Hawaiiian Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 2 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 11 sites at French Frigate Shoals...

  20. CRED REA Fish Team Belt Transect Survey at French Frigate Shoals, NW Hawaiian Islands, 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 10 sites at French Frigate Shoals...

  1. CRED REA Fish Team Stationary Point Count Surveys at Stingray Shoals, 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Stationary Point Counts at 4 stations at each survey site were surveyed as part of Rapid Ecological Assessments conducted at 2 sites at Stingray Shoals in the...

  2. CRED REA Fish Team Belt Transect Survey at Stingray Shoals, 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 2 sites at Stingray Shoals in the...

  3. Density and group size influence shoal cohesion, but not coordination in zebrafish (Danio rerio).

    Science.gov (United States)

    Shelton, Delia S; Price, Brittany C; Ocasio, Karen M; Martins, Emília P

    2015-02-01

    The formations made by gregarious animals can range from loose aggregates to highly synchronized and ordered structures. For very large, coordinated groups, both physical and social environments are important for determining the physical arrangement of individuals in the group. Here we tested whether physical and social factors are also important in determining the structure of small, loosely coordinated groups of zebrafish. We found that even though our fish were not crowded and did not use most of the available space, the distance between individual fish was explained primarily by the amount of available space (i.e., density). Zebrafish in a larger space spread out more and the total dimensions of the shoal were an additive function also of group size. We, however, did not find any impact of social or physical environment on the orientation of individual fish or shoal. Thus, both physical and social factors were important for shoal spatial arrangements, but not individual orientation and shoal alignment.

  4. CRED REA Fish Team Stationary Point Count Surveys at French Frigate Shoals, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Stationary Point Counts at 4 stations at each survey site were surveyed as part of Rapid Ecological Assessments conducted at 9 sites at French Frigate Shoals in...

  5. CRED REA Fish Team Belt Transect Surveys at French frigate Shoals, 2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at French Frigate Shoals...

  6. CRED REA Fish Team Stationary Point Count Surveys at French Frigate Shoals, 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Stationary Point Counts at 4 stations at each survey site were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at French Frigate Shoals in...

  7. CRED REA Coral Population Parameters at French Frigate Shoals, Northwestern Hawaiiian Islands, 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 2 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 12 sites at French Frigate Shoals...

  8. Gridded bathymetry of French Frigate Shoals, Hawaii, USA - Arc ASCII format

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry (5m) of the shelf environment of French Frigate Shoals, Hawaii, USA. The ASCII includes multibeam bathymetry from the Simrad EM3002d, and Reson...

  9. Legacy French Frigate Shoals (FFS) Area Landings and Standardized Bottomfish CPUE

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a legacy data set containing area landings and standardized bottomfish CPUE in the vicinity of French Frigate Shoals in the Northwestern Hawaiian Islands.

  10. CRED REA Algal Assessments, French Frigate Shoals, Northwestern Hawaiian Islands 2004 (NODC Accession 0010352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines as part of Rapid Ecological Assessments conducted at 11 sites at French Frigate Shoals...

  11. CRED REA Algal Assessments, French Frigate Shoals, Northwestern Hawaiian Islands 2003 (NODC Accession 0010352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines as part of Rapid Ecological Assessments conducted at 12 sites at French Frigate Shoals...

  12. CRED REA Algal Assessments, French Frigate Shoals, Northwestern Hawaiian Islands 2002 (NODC Accession 0010352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines as part of Rapid Ecological Assessments conducted at 12 sites at French Frigate Shoals...

  13. Hybridization threatens shoal bass populations in the Upper Chattahoochee River Basin: Chapter 37

    Science.gov (United States)

    Dakin, Elizabeth E; Porter, Brady A.; Freeman, Byron J.; Long, James M.; Tringali, Michael D.; Long, James M.; Birdsong, Timothy W.; Allen, Micheal S.

    2015-01-01

    Shoal bass are native only to the Apalachicola-Chattahoochee-Flint river system of Georgia, Alabama, and Florida, and are vulnerable to extinction as a result of population fragmentation and introduction of non-native species. We assessed the genetic integrity of isolated populations of shoal bass in the upper Chattahoochee River basin (above Lake Lanier, Big Creek, and below Morgan Falls Dam) and sought to identify rates of hybridization with non-native, illegally stocked smallmouth bass and spotted bass.

  14. Numerical Study on Breaking Criteria for Solitary Waves

    Institute of Scientific and Technical Information of China (English)

    Chung-ren CHOU; Ruey-syan SHIH; John Z. YIM

    2003-01-01

    Studies of the breaking criteria for solitary waves on a slope are presented in this paper. The boundary element method is used to model the processes of shoaling and breaking of solitary waves on various slopes. Empirical formulae that can be used to characterize the breaking of solitary waves are presented. These include the breaking index, the wave height, the water depth, and the maximum particle velocity at the point of breaking. Comparisons with the results of other researches are given.

  15. Influence green sand system by core sand additions

    Directory of Open Access Journals (Sweden)

    N. Špirutová

    2012-01-01

    Full Text Available Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?”This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition. Ratio of active betonite by Methylene blue test was also determined.

  16. A Boussinesq Equation-Based Model for Nearshore Wave Breaking

    Institute of Scientific and Technical Information of China (English)

    余建星; 张伟; 王广东; 杨树清

    2004-01-01

    Based on the wave breaking model by Li and Wang (1999), this work is to apply Dally' s analytical solution to the wave-height decay irstead of the empirical and semi-empirical hypotheses of wave-height distribution within the wave breaking zone. This enhances the applicability of the model. Computational results of shoaling, location of wave breaking, wave-height decay after wave breaking, set-down and set-up for incident regular waves are shown to have good agreement with experimental and field data.

  17. Sands cykliske styrke

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    1992-01-01

    Sands cykliske styrke kan beskrives ved Cyclic Liquefaction, Mobilisering, Stabilization og Instant Stabilization. I artiklen beskrives hvorfor Stabilization og Instant Stabilization ikke observeres, når sands udrænede styrke undersøges i triaxial celler, der anvender prøver med dobbelt prøvehøjde....

  18. Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Bødker, Lars Bødker

    The Soil Mechanics Laboratory has started performing tests with a new sand, Baskarp No 15. Baskarp No 15 is a graded sand from Sweden. The shapes of the largest grains are round, while the small grains have sharp edges. The main part of of Baskarp No 15 is quarts, but it also contains feldspar...

  19. Attenuation of Seismic Waves at Regional Distances

    Science.gov (United States)

    1984-11-27

    States (SALMON, GASBUOG, RULISON and RIO BLANCA) and in the French Sahara ( SAPHIR and RUBIS). The hard-rook ITS calibration curve, when applied to these...so that two of the explosions, SAPHIR and RUBIS, had measure- able Lg-wave amplitudes. Figure 4 gives an example of Lg waves of SAPHIR recorded at...for RUBIS and SAPHIR . Station HLW is in Egypt, and SDB in Angola. Both shots were in granite. For the Nevada explosions SHOAL and PILEDRIVER, also in

  20. The effect of progressive hypoxia on spontaneous activity in single and shoaling golden grey mullet Liza aurata.

    Science.gov (United States)

    Lefrançois, C; Ferrari, R S; Moreira da Silva, J; Domenici, P

    2009-11-01

    The hypothesis of a differential effect of hypoxia on activity in shoaling v. solitary fish was tested in golden grey mullet Liza aurata. In both solitary and shoaling fish, (1) swimming activity increased significantly at shoaling than in solitary fish, possibly due to social interactions in shoaling fish. Despite showing a higher swimming activity, shoaling individuals showed similar ventilation frequency to the less active solitary fish. This suggests that shoaling exerts a calming effect on L. aurata, probably related to increased safety while in numbers. In addition, shoaling fish spent a higher proportion of time performing aquatic surface respiration at 15% air saturation (i.e. the highest oxygen level at which aquatic surface respiration was observed) than solitary fish, possibly because of (1) synchronization of aquatic surface respiration in shoaling fish and (2) lower risk of predation perceived by shoaling fish.

  1. Factors controlling navigation-channel Shoaling in Laguna Madre, Texas

    Science.gov (United States)

    Morton, R.A.; Nava, R.C.; Arhelger, M.

    2001-01-01

    Shoaling in the Gulf Intracoastal Waterway of Laguna Madre, Tex., is caused primarily by recycling of dredged sediments. Sediment recycling, which is controlled by water depth and location with respect to the predominant wind-driven currents, is minimal where dredged material is placed on tidal flats that are either flooded infrequently or where the water is extremely shallow. In contrast, nearly all of the dredged material placed in open water >1.5 m deep is reworked and either transported back into the channel or dispersed into the surrounding lagoon. A sediment flux analysis incorporating geotechnical properties demonstrated that erosion and not postemplacement compaction caused most sediment losses from the placement areas. Comparing sediment properties in the placement areas and natural lagoon indicated that the remaining dredged material is mostly a residual of initial channel construction. Experimental containment designs (shallow subaqueous mound, submerged levee, and emergent levee) constructed in high-maintenance areas to reduce reworking did not retain large volumes of dredged material. The emergent levee provided the greatest retention potential approximately 2 years after construction.

  2. Invasive Bighead and Silver Carps Form Different Sized Shoals that Readily Intermix.

    Directory of Open Access Journals (Sweden)

    Ratna Ghosal

    Full Text Available Two species of congeneric filter-feeding microphagous carps from Asia, the bighead and the silver carp, were recently introduced to North America and have become highly invasive. These species of carp have similar food habits but the silver carp has the unique habit of jumping when disturbed. Both species have complex but poorly understood social behaviors and while both are thought to aggregate (form groups and shoal (form tight social groups, this possibility has not yet been examined in these species. The present study examined the grouping tendencies of these species in the laboratory and the effects of fish density and species identity on it. Using nearest neighbor distance (NND as a metric, we showed that both juvenile bighead and juvenile silver carp grouped (aggregate strongly (P0.05 on this behavior. Within aggregations, bighead carp tended to form a single large shoal while silver carp formed shoals of 2-3 individuals. Further, when tested as mixed-species groups, bighead and silver carp readily shoaled with each other but not with the common carp, which is from Eurasia and a member of another feeding guild. Due to their similar feeding strategies, we speculate that the bighead and silver carp tend to aggregate and shoal to facilitate both their foraging efforts and to avoid predation, while the differences in the size of the shoals they form may seemingly reflect their different anti-predation strategies. These complex shoaling behaviors likely influence Asian carp distribution in rivers, and thus how they might be sampled and managed.

  3. Invasive Bighead and Silver Carps Form Different Sized Shoals that Readily Intermix.

    Science.gov (United States)

    Ghosal, Ratna; Xiong, Peter X; Sorensen, Peter W

    2016-01-01

    Two species of congeneric filter-feeding microphagous carps from Asia, the bighead and the silver carp, were recently introduced to North America and have become highly invasive. These species of carp have similar food habits but the silver carp has the unique habit of jumping when disturbed. Both species have complex but poorly understood social behaviors and while both are thought to aggregate (form groups) and shoal (form tight social groups), this possibility has not yet been examined in these species. The present study examined the grouping tendencies of these species in the laboratory and the effects of fish density and species identity on it. Using nearest neighbor distance (NND) as a metric, we showed that both juvenile bighead and juvenile silver carp grouped (aggregate) strongly (P0.05) on this behavior. Within aggregations, bighead carp tended to form a single large shoal while silver carp formed shoals of 2-3 individuals. Further, when tested as mixed-species groups, bighead and silver carp readily shoaled with each other but not with the common carp, which is from Eurasia and a member of another feeding guild. Due to their similar feeding strategies, we speculate that the bighead and silver carp tend to aggregate and shoal to facilitate both their foraging efforts and to avoid predation, while the differences in the size of the shoals they form may seemingly reflect their different anti-predation strategies. These complex shoaling behaviors likely influence Asian carp distribution in rivers, and thus how they might be sampled and managed.

  4. Effects of Building a Sand Barrier Berm to Mitigate the Effects of the Deepwater Horizon Oil Spill on Louisiana Marshes

    Science.gov (United States)

    Lavoie, Dawn; Flocks, James G.; Kindinger, Jack G.; Sallenger, A.H.; Twichell, David C.

    2010-01-01

    The State of Louisiana requested emergency authorization on May 11, 2010, to perform spill mitigation work on the Chandeleur Islands and on all the barrier islands from Grand Terre Island eastward to Sandy Point to enhance the capability of the islands to reduce the movement of oil from the Deepwater Horizon oil spill to the marshes. The proposed action-building a barrier berm (essentially an artificial island fronting the existing barriers and inlets) seaward of the existing barrier islands and inlets-'restores' the protective function of the islands but does not alter the islands themselves. Building a barrier berm to protect the mainland wetlands from oil is a new strategy and depends on the timeliness of construction to be successful. Prioritizing areas to be bermed, focusing on those areas that are most vulnerable and where construction can be completed most rapidly, may increase chances for success. For example, it may be easier and more efficient to berm the narrow inlets of the coastal section to the west of the Mississippi River Delta rather than the large expanses of open water to the east of the delta in the southern parts of the Breton National Wildlife Refuge (NWR). This document provides information about the potential available sand resources and effects of berm construction on the existing barrier islands. The proposed project originally involved removing sediment from a linear source approximately 1 mile (1.6 km) gulfward of the barrier islands and placing it just seaward of the islands in shallow water (~2-m depth where possible) to form a continuous berm rising approximately 6 feet (~2 m) above sea level (North American Vertical Datum of 1988-NAVD88) with an ~110-yd (~100-m) width at water level and a slope of 25:1 to the seafloor. Discussions within the U.S. Geological Survey (USGS) and with others led to the determination that point-source locations, such as Hewes Point, the St. Bernard Shoals, and Ship Shoal, were more suitable 'borrow

  5. Analysis of nonlinear internal waves in the New York Bight

    Science.gov (United States)

    Liu, Antony K.

    1988-01-01

    An analysis of the nonlinear-internal-wave evolution in the New York Bight was performed on the basis of current meter mooring data obtained in the New York Bight during the SAR Internal Wave Signature Experiment (SARSEX). The solitary wave theory was extended to include dissipation and shoaling effects, and a series of numerical experiments were performed by solving the wave evolution equation, with waveforms observed in the SARSEX area as initial conditions. The results of calculations demonstrate that the relative balance of dissipation and shoaling effects is crucial to the detailed evolution of internal wave packets. From an observed initial wave packet at the upstream mooring, the numerical evolution simulation agreed reasonably well with the measurements at the distant mooring for the leading two large solitons.

  6. Sand and Gravel Deposits

    Data.gov (United States)

    Vermont Center for Geographic Information — This dataset is a statewide polygon coverage of sand, gravel, and stone resources. This database includes the best data available from the VT Agency of Natural...

  7. Sand and Gravel Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes sand and gravel operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...

  8. Vestled - Hvide Sande

    DEFF Research Database (Denmark)

    Juel-Christiansen, Carsten; Hesselbjerg, Marianne; Schønherr, Torben

    2009-01-01

    Værket Vestled i Hvide Sande præsenteret i sammenhæng af 1000 nutidige landskabsarkitektoniske arbejder fra hele verden, hvor hvert værk vises på én side......Værket Vestled i Hvide Sande præsenteret i sammenhæng af 1000 nutidige landskabsarkitektoniske arbejder fra hele verden, hvor hvert værk vises på én side...

  9. MECHANICAL REGENERATION OF SAND WASTE

    Directory of Open Access Journals (Sweden)

    D. I. Gnir

    2005-01-01

    Full Text Available The experimental activation of the sand regenerator of the firm SINTO is carried out at ОАО “MZOO". It is shown that sand grains are cleared from films of binding agents, that allows to use the treated sand for preparation of agglutinant and core sands.

  10. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... Shoals; naval aircraft bombing target area. (a) The danger zone. A circular area with a radius of 500...

  11. Feeding ecology of long-tailed ducks Clangula hyemalis wintering on the Nantucket Shoals

    Science.gov (United States)

    White, Timothy P.; Veit, Richard R.; Perry, Matthew C.

    2009-01-01

    A substantial proportion, perhaps 30%, of the North American breeding population of Long-tailed Ducks (Clangula hyemalis) winter in the vicinity of Nantucket Island, Massachusetts. These birds spend the night on Nantucket Sound and commute during daylight hours to the Nantucket Shoals, which extend about 65 km offshore from the southeastern corner of Nantucket. Strip transects done from a single-engine plane in 1997 and 1998 indicated that Long-tailed Ducks foraged over the shallower (<= 20 m depth) portions of the Nantucket Shoals, up to 70 km offshore. Diet analyses of ten birds collected in February 1999 and five in December 2006 showed that they fed principally (106.6 +/- 42.0 individuals per crop) on Gammarus annulatus, a pelagic amphipod that often forms large aggregations, and is consumed by several species of fish and marine mammals. Our findings emphasize the importance of conservation of the Nantucket Shoals and the prevention of oil spills or other potentially harmful accidents.

  12. Hydrodynamic and Sediment Transport Model Application for OSAT3 Guidance: Ratio of wave- and current-induced shear stress to critical values for oil-sand ball and sediment mobilization

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey has developed a method for estimating the mobility and potential alongshore transport of heavier-than-water sand and oil agglomerates...

  13. Hydrodynamic and Sediment Transport Model Application for OSAT3 Guidance: Surf-zone integrated alongshore potential flux for oil-sand balls of varying sizes weighted by probability of wave scenario occurrence

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey has developed a method for estimating the mobility and potential alongshore transport of heavier-than-water sand and oil agglomerates...

  14. Hydrodynamic and Sediment Transport Model Application for OSAT3 Guidance: Ratio of wave- and current-induced shear stress to critical values for oil-sand ball and sediment mobilization

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey has developed a method for estimating the mobility and potential alongshore transport of heavier-than-water sand and oil agglomerates...

  15. Hydrodynamic and Sediment Transport Model Application for OSAT3 Guidance: Surf-zone integrated alongshore potential flux for oil-sand balls of varying sizes weighted by probability of wave scenario occurrence

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey has developed a method for estimating the mobility and potential alongshore transport of heavier-than-water sand and oil agglomerates...

  16. Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

    Energy Technology Data Exchange (ETDEWEB)

    K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

    2004-03-01

    Groundwater flow and radionuclide transport at the Shoal underground nuclear test are characterized using three-dimensional numerical models, based on site-specific hydrologic data. The objective of this modeling is to provide the flow and transport models needed to develop a contaminant boundary defining the extent of radionuclide-contaminated groundwater at the site throughout 1,000 years at a prescribed level of confidence. This boundary will then be used to manage the Project Shoal Area for the protection of the public and the environment.

  17. Shoreline instability under low-angle wave incidence

    NARCIS (Netherlands)

    Idier, D.; Falqués, A.; Ruessink, B.G.; Garnier, R.

    2011-01-01

    The growth of megacusps as shoreline instabilities is investigated by examining the coupling between wave transformation in the shoaling zone, longshore transport in the surf zone, cross-shore transport, and morphological evolution. This coupling is known to drive a potential positive feedback in ca

  18. Mechanic waves in sand: effect of polydispersity

    NARCIS (Netherlands)

    Luding, S.; Mouraille, O.; Peukert, W.; Schreglmann, C.

    2008-01-01

    The sound propagation mechanisms inside dense granular matter are challenging the attempts to describe it because of the discrete nature of the material. Phenomena like dissipation, scattering, and dispersion are hard to predict based on the material state and/or properties and vice-versa. We propos

  19. 福建闽江口和九龙江口外线状沉积沙体特征%The characteristics of linear sands off Minjiang Estuary and Jiulongjiang Estuary in Fujian,China

    Institute of Scientific and Technical Information of China (English)

    许艳; 蔡锋; 卢惠泉; 吴承强; 郑勇玲; 鲍晶晶

    2014-01-01

    福建沿海强潮河口闽江口和九龙江口外均发育有一定规模的线状沉积沙体,通过多波束调查采集数据和浅剖、沉积物资料的分析,对此类沙体特征进行研究,初步认为其为潮流沙脊。结果表明:在平面分布上,闽江口外潮流沙脊走向近SW-NE向,沙脊局部连片;九龙江口外沙脊走向近 ENE-WSW向,沙脊末端有分叉现象。分析现代海洋环境作用并结合沙脊规模、水深和河口相对关系的研究显示,沙脊主体规模基本稳定,现代水动力仅对沙脊表面有改造作用。在潮流、波浪和近岸余流的共同作用下沙脊脊顶部略显平滑,两翼坡度较缓,其沉积物组成以粒度较粗的古河口砂质浅滩砂为主,沉积主体为全新世海平面上升时期,近岸河口环境的古水下三角洲遭受潮流侵蚀而成。%A certain scale of linear submarine sands which are referred to as tidal sand ridges occurs off the Minjiang Estuary and the Jiulongjiang Estuary in Fujian .Based on the survey data by multi-beam acoustic sounding ,sub-bottom profile as well as sediment grain sizes analysis ,we studied the features of the tidal sand ridges .The results show that the sand ridges off the Minjiang Estuary are oriented NE -SW ,and some of them are connected .The sand ridges off the Jiulongjiang Estuary are oriented ENE -WSW ,and some appear to diverge on the end .Accord-ing to the analysis of marine hydrodynamic environment affects ,and the relation among the ridges scale ,depth and relative distance to the estuary ,the main body of the sand ridges is basically steady .They have been reformed by the recent hydrodynamics as evidenced by similar sand waves on both sides of flanks .The interaction by recent tid-al current ,wave and residual current leads to a relatively smooth surface on top and both flanks of the sand ridges . It's indicated that the tidal sands primarily originated from estuarine coarse sandy shoals on

  20. Comparison of buried sand ridges and regressive sand ridges on the outer shelf of the East China Sea

    Science.gov (United States)

    Wu, Ziyin; Jin, Xianglong; Zhou, Jieqiong; Zhao, Dineng; Shang, Jihong; Li, Shoujun; Cao, Zhenyi; Liang, Yuyang

    2016-07-01

    Based on multi-beam echo soundings and high-resolution single-channel seismic profiles, linear sand ridges in U14 and U2 on the East China Sea (ECS) shelf are identified and compared in detail. Linear sand ridges in U14 are buried sand ridges, which are 90 m below the seafloor. It is presumed that these buried sand ridges belong to the transgressive systems tract (TST) formed 320-200 ka ago and that their top interface is the maximal flooding surface (MFS). Linear sand ridges in U2 are regressive sand ridges. It is presumed that these buried sand ridges belong to the TST of the last glacial maximum (LGM) and that their top interface is the MFS of the LGM. Four sub-stage sand ridges of U2 are discerned from the high-resolution single-channel seismic profile and four strikes of regressive sand ridges are distinguished from the submarine topographic map based on the multi-beam echo soundings. These multi-stage and multi-strike linear sand ridges are the response of, and evidence for, the evolution of submarine topography with respect to sea-level fluctuations since the LGM. Although the difference in the age of formation between U14 and U2 is 200 ka and their sequences are 90 m apart, the general strikes of the sand ridges are similar. This indicates that the basic configuration of tidal waves on the ECS shelf has been stable for the last 200 ka. A basic evolutionary model of the strata of the ECS shelf is proposed, in which sea-level change is the controlling factor. During the sea-level change of about 100 ka, five to six strata are developed and the sand ridges develop in the TST. A similar story of the evolution of paleo-topography on the ECS shelf has been repeated during the last 300 ka.

  1. Comparison of buried sand ridges and regressive sand ridges on the outer shelf of the East China Sea

    Science.gov (United States)

    Wu, Ziyin; Jin, Xianglong; Zhou, Jieqiong; Zhao, Dineng; Shang, Jihong; Li, Shoujun; Cao, Zhenyi; Liang, Yuyang

    2017-06-01

    Based on multi-beam echo soundings and high-resolution single-channel seismic profiles, linear sand ridges in U14 and U2 on the East China Sea (ECS) shelf are identified and compared in detail. Linear sand ridges in U14 are buried sand ridges, which are 90 m below the seafloor. It is presumed that these buried sand ridges belong to the transgressive systems tract (TST) formed 320-200 ka ago and that their top interface is the maximal flooding surface (MFS). Linear sand ridges in U2 are regressive sand ridges. It is presumed that these buried sand ridges belong to the TST of the last glacial maximum (LGM) and that their top interface is the MFS of the LGM. Four sub-stage sand ridges of U2 are discerned from the high-resolution single-channel seismic profile and four strikes of regressive sand ridges are distinguished from the submarine topographic map based on the multi-beam echo soundings. These multi-stage and multi-strike linear sand ridges are the response of, and evidence for, the evolution of submarine topography with respect to sea-level fluctuations since the LGM. Although the difference in the age of formation between U14 and U2 is 200 ka and their sequences are 90 m apart, the general strikes of the sand ridges are similar. This indicates that the basic configuration of tidal waves on the ECS shelf has been stable for the last 200 ka. A basic evolutionary model of the strata of the ECS shelf is proposed, in which sea-level change is the controlling factor. During the sea-level change of about 100 ka, five to six strata are developed and the sand ridges develop in the TST. A similar story of the evolution of paleo-topography on the ECS shelf has been repeated during the last 300 ka.

  2. Microbes in Beach Sands: Integrating Environment, Ecology and Public Health.

    Science.gov (United States)

    Whitman, Richard; Harwood, Valerie J; Edge, Thomas A; Nevers, Meredith; Byappanahalli, Muruleedhara; Vijayavel, Kannappan; Brandão, João; Sadowsky, Michael J; Alm, Elizabeth Wheeler; Crowe, Allan; Ferguson, Donna; Ge, Zhongfu; Halliday, Elizabeth; Kinzelman, Julie; Kleinheinz, Greg; Przybyla-Kelly, Kasia; Staley, Christopher; Staley, Zachery; Solo-Gabriele, Helena M

    2014-09-01

    Beach sand is a habitat that supports many microbes, including viruses, bacteria, fungi and protozoa (micropsammon). The apparently inhospitable conditions of beach sand environments belie the thriving communities found there. Physical factors, such as water availability and protection from insolation; biological factors, such as competition, predation, and biofilm formation; and nutrient availability all contribute to the characteristics of the micropsammon. Sand microbial communities include autochthonous species/phylotypes indigenous to the environment. Allochthonous microbes, including fecal indicator bacteria (FIB) and waterborne pathogens, are deposited via waves, runoff, air, or animals. The fate of these microbes ranges from death, to transient persistence and/or replication, to establishment of thriving populations (naturalization) and integration in the autochthonous community. Transport of the micropsammon within the habitat occurs both horizontally across the beach, and vertically from the sand surface and ground water table, as well as at various scales including interstitial flow within sand pores, sediment transport for particle-associated microbes, and the large-scale processes of wave action and terrestrial runoff. The concept of beach sand as a microbial habitat and reservoir of FIB and pathogens has begun to influence our thinking about human health effects associated with sand exposure and recreational water use. A variety of pathogens have been reported from beach sands, and recent epidemiology studies have found some evidence of health risks associated with sand exposure. Persistent or replicating populations of FIB and enteric pathogens have consequences for watershed/beach management strategies and regulatory standards for safe beaches. This review summarizes our understanding of the community structure, ecology, fate, transport, and public health implications of microbes in beach sand. It concludes with recommendations for future work in

  3. Bituminous sands : tax issues

    Energy Technology Data Exchange (ETDEWEB)

    Patel, B. [PricewaterhouseCoopers LLP, Calgary, AB (Canada)

    2004-07-01

    This paper examined some of the tax issues associated with the production of bitumen or synthetic crude oil from oil sands. The oil sands deposits in Alberta are gaining more attention as the supplies of conventional oil in Canada decline. The oil sands reserves located in the Athabasca, Cold Lake and Peace River areas contain about 2.5 trillion barrels of highly viscous hydrocarbons called bitumen, of which nearly 315 billion barrels are recoverable with current technology. The extraction method varies for each geographic area, and even within zones and reservoirs. The two most common extraction methods are surface mining and in-situ extraction such as cyclic steam stimulation (CSS); low pressure steam flood; pressure cycle steam drive; steam assisted gravity drainage (SAGD); hot water flooding; and, fire flood. This paper also discussed the following general tax issues: bituminous sands definition; bituminous sands leases and Canadian development expense versus Canadian oil and gas property expense (COGPE); Canadian exploration expense (CEE) for surface mining versus in-situ methods; additional capital cost allowance; and, scientific research and experimental development (SR and ED). 15 refs.

  4. Incipient Motion of Sand and Oil Agglomerates

    Science.gov (United States)

    Nelson, T. R.; Dalyander, S.; Jenkins, R. L., III; Penko, A.; Long, J.; Frank, D. P.; Braithwaite, E. F., III; Calantoni, J.

    2016-12-01

    Weathered oil mixed with sediment in the surf zone in the northern Gulf of Mexico after the 2010 Deepwater Horizon oil spill, forming large mats of sand and oil. Wave action fragmented the mats into sand and oil agglomerates (SOAs) with diameters of about 1 to 10 cm. These SOAs were transported by waves and currents along the Gulf Coast, and have been observed on beaches for years following the spill. SOAs are composed of 70%-95% sand by mass, with an approximate density of 2107 kg/m³. To measure the incipient motion of SOAs, experiments using artificial SOAs were conducted in the Small-Oscillatory Flow Tunnel at the U.S. Naval Research Laboratory under a range of hydrodynamic forcing. Spherical and ellipsoidal SOAs ranging in size from 0.5 to 10 cm were deployed on a fixed flat bed, a fixed rippled bed, and a movable sand bed. In the case of the movable sand bed, SOAs were placed both proud and partially buried. Motion was tracked with high-definition video and with inertial measurement units embedded in some of the SOAs. Shear stress and horizontal pressure gradients, estimated from velocity measurements made with a Nortek Vectrino Profiler, were compared with observed mobility to assess formulations for incipient motion. For SOAs smaller than 1 cm in diameter, incipient motion of spherical and ellipsoidal SOAs was consistent with predicted critical stress values. The measured shear stress at incipient motion of larger, spherical SOAs was lower than predicted, indicating an increased dependence on the horizontal pressure gradient. In contrast, the measured shear stress required to move ellipsoidal SOAs was higher than predicted, even compared to values modified for larger particles in mixed-grain riverine environments. The laboratory observations will be used to improve the prediction of incipient motion, transport, and seafloor interaction of SOAs.

  5. Lund Sand No 0

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Jakobsen, Finn Rosendal

    During the last 15 years the Geotechnical Engineering Group (GEG) at Aalborg University has performed triaxial tests with a sand called Lund No 0. Lund No 0 is a graded sand from a gravel pit near Horsens in Denmark. For the classification of the sand the following tests have been performed: Sieve...... test, Grain density, ds, Maximum, emax, and minimum, emin, void ratio. The strength parameters of Lund No 0 are detennined by some drained and undrained triaxial tests in the Danish Triaxial Cell. The Danish Triaxial Cell prescribes smooth pressure heads and specimens with equal height and diameter....... Four series with Id equal to 0.92, 0.87 0.76 and 0.55 have been performed....

  6. Modelling of nonlinear shoaling based on stochastic evolution equations

    DEFF Research Database (Denmark)

    Kofoed-Hansen, Henrik; Rasmussen, Jørgen Hvenekær

    1998-01-01

    A one-dimensional stochastic model is derived to simulate the transformation of wave spectra in shallow water including generation of bound sub- and super-harmonics, near-resonant triad wave interaction and wave breaking. Boussinesq type equations with improved linear dispersion characteristics...... are recast into evolution equations for the complex amplitudes, and serve as the underlying deterministic model. Next, a set of evolution equations for the cumulants is derived. By formally introducing the well-known Gaussian closure hypothesis, nonlinear evolution equations for the power spectrum...... and bispectrum are derived. A simple description of depth-induced wave breaking is incorporated in the model equations, assuming that the total rate of dissipation may be distributed in proportion to the spectral energy density on each discrete frequency. The proposed phase-averaged model is compared...

  7. UK Frac Sand Resources

    OpenAIRE

    Mitchell, C J

    2015-01-01

    Although still just a glimmer in the gas man’s eye, the prospect of shale hydrocarbon (oil and gas) development in the UK has many companies thinking about the industrial minerals it will require. Chief amongst these is silica sand which is used as a ‘proppant’ in the hydraulic fracturing, or ‘fracking’, of shales to help release the gas. The UK has large resources of sand and sandstone, of which only a small proportion have the necessary technical properties that classify them as ‘silica san...

  8. Small Strain Behaviour and Viscous Effects on Sands and Sand-Clay Mixtures

    Science.gov (United States)

    Di Benedetto, H.

    This lecture paper focuses on sands and sand-clay mixtures behaviour in the small strain domain. Non viscous and viscous components are measured, identified and modelled within the framework of a 3 component model. Two precision prototype devices (triaxial and hollow cylinder) both equipped with piezoelectric sensors are used. Non viscous measured behaviour considering small quasi-static cycles and wave properties are compared with simulations obtained from 2 recently formulated anisotropic hypoelastic models (DBGS and DBGSP). Then, viscous experimental part is compared with the proposed model prediction. This model is an asymptotic expression, for the small strain domain, of a viscous evanescent formalism proposed by the author. It takes into account very peculiar behaviour observed on sands. Simulation for loadings with and without rotation of axes and for different rate histories, are quite satisfactory.

  9. Quantification acuity in spontaneous shoaling decisions of three-spined sticklebacks.

    Science.gov (United States)

    Mehlis, Marion; Thünken, Timo; Bakker, Theo C M; Frommen, Joachim G

    2015-09-01

    The ability to discriminate between different quantities is widespread throughout the animal kingdom, and the underlying mechanisms of quantity discrimination are currently intensely discussed. In contrast, questions elucidating the limits of quantity estimation received rather little attention so far. Here, we examined fine-tuned quantity estimation in the three-spined stickleback (Gasterosteus aculeatus) in a natural context, i.e. during shoaling decisions. Wild-caught focal fish were given the spontaneous choice between two shoals which differed in group size by 1 fish (0 vs. 1, 1 vs. 2, 2 vs. 3, 3 vs. 4, 4 vs. 5, 5 vs. 6 and 6 vs. 7), based on visual assessment. The results show that sticklebacks generally prefer to shoal with the larger group. They discriminated numerical contrasts up to 6 versus 7, equalling a numerical ratio of 0.86. Preference patterns followed Weber's law, i.e. decreased with increasing numerical ratio. This pattern was found across all numerical conditions as well as within the small number range (ranging from 1 vs. 2 to 3 vs. 4). The results suggest that wild-caught three-spined sticklebacks are spontaneously able (i.e. without prior learning) to detect subtle differences in shoal sizes. Further, they confirm findings of previous studies highlighting the contribution of the analogue magnitude system to quantity estimation in fishes.

  10. French Frigate Shoals Site P3 11/2/2002 28-29M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 28 and 29 meters along a permanent transect.

  11. Research on Diageneses of Cambrian Shoal Facies Carbonate Rocks in the Xiadong Area, Hubei Province

    Institute of Scientific and Technical Information of China (English)

    张秀莲; 蒋凌志

    2001-01-01

    With continuous outcrops, developed shoal facies rocks, complete types of diagenesis and changeable diagenetic environments, Cambrian strata are well developed in the Xiadong area, Yichang, Hubei Province. Under the combined influence of numerous diageneses, secondary pores can be formed, which result in better reservoir properties of the rock strata. The Cambrian rocks in this area consist of mainly carbonate rocks and secondarily detrital rocks. The carbonate rocks are dominated by grainstones including wormkalk, calcirudite-calcarenite, oolitic limestone and oncolitic limestone. Graded bedding and cross bedding are well developed in the strata, which indicates that the formation environment is of a high-energy shoal facies. In this area, there has developed a sequence of stable Cambrian platform carbonate deposition. The evolution trend is as follows: open sea shelf facies? intertidal low-energy restricted sea facies? intertidal high-energy shoal facies? coastal shoal facies? evaporite tidal-flat facies. The diageneses that the strata have experienced mainly include dolomitization, dedolomitization and dissolution, which are constructive diageneses for the formation of secondary pores, such as intercrystal pores, intercrystal solution pores, gypsum mold pores and caverns of dolomite. The diagenetic facies intervals can be divided into the unitary and the compound ones, totalling 22 in the area. In the early atmospheric fresh-water diagenetic environment and the late epidiagenetic environment, Cambrian rocks, especially dolomite of the Middle and Upper Cambrian, experienced extensive and profound fresh water corrosion, forming pore intervals with a porosity ranging from 5% to 15%.

  12. French Frigate Shoals Site P16 9/14/2001 45-46M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 45 and 46 meters along a permanent transect.

  13. French Frigate Shoals Site P13 10/31/2002 29-30M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 29 and 30 meters along a permanent transect.

  14. French Frigate Shoals Site P5 11/2/2002 30-31M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 30 and 31 meters along a permanent transect.

  15. French Frigate Shoals Site P3 9/11/2002 5-6M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769N, 166.261W), between 5 and 6 meters along a permanent transect.

  16. French Frigate Shoals Site P3 11/2/2002 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 14 and 15 meters along a permanent transect.

  17. French Frigate Shoals Site P16 10/4/2002 40-41M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 40 and 41 meters along a permanent transect.

  18. Long-term Monitoring Plan for the Shoal Underground Nuclear Test

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed Hassan

    2005-02-01

    The flow and transport model of Shoal is used to design a three-well monitoring network to be part of the long-term monitoring network for the site and achieve two objectives: (1) detect the presence of radionuclides in case they migrate to the monitoring well locations, and (2) provide field data to compare with model predictions as part of the model validation process. Using three different quantitative approaches and the numerical groundwater flow and transport model developed for Shoal, three new monitoring well locations were identified from 176 different networks. In addition to the quantitative analyses using the numerical model, the development of the monitoring network for Shoal will also be subject to qualitative hydrogeologic interpretation during implementation. information will only be available during the fieldwork, it will be incorporated in the monitoring well design at the time of well installation. Finally, it should be noted that the CADD-CAP for Shoal, including the compliance boundary, is not yet approved. Should the compliance boundary change from the 1,000-year MCL contaminant boundary, well locations may also need to change. However, the analysis reported here provides a number of alternatives with reasonable detection efficiency.

  19. Tidal characteristics in the Wenzhou offshore waters and changes resulting from the Wenzhou Shoal Reclamation Project

    Science.gov (United States)

    Bao, Min; Bao, Xianwen; Yu, Huaming; Ding, Yang

    2015-12-01

    The Wenzhou Shoal Reclamation Project is the core part of Wenzhou Peninsula Engineering which is a big comprehensive development project to expand the city space. The dynamics of the surrounding area was proved to suffer little effect in response to the Lingni north dyke since it was built approximately along the current direction. Therefore, this paper focuses firstly on the tidal characteristics in the Wenzhou and Yueqing bays with the Lingni north dyke being built and then on the changes resulting from the implementation of the on-going Wenzhou Shoal Reclamation Project (WSRP) which will reclaim land from the whole Wenzhou Shoal. To simulate the tidal dynamics, a high-resolution coastal ocean model with unstructured triangular grids was set up for the Wenzhou and Yueqing Bays. The model resolved the complicated tidal dynamics with the simulated tidal elevation and current in good agreement with observations. In the study area, M2 is the predominant tidal component, which means the tide is semidiurnal. The new reclamation project hardly affects the Yueqing Bay and the open ocean, but there are concentrated effects on the mouth of the southern branch of the Oujiang River and the southwest of Wenzhou Shoal. This study provides an indicative reference to the local government and helps to weigh the advantages and disadvantages of the project.

  20. Seismotectonics of Taiwan Shoal region in northeastern SCS: Insights from crustal structure

    Science.gov (United States)

    Kuiyuan, Wan; Jinlong, Sun; Shaohong, Xia; Xiaoling, Xie; Xiang, Zhang; Huilong, Xu; Jinghe, Cao

    2017-04-01

    A seismicity cluster and a great 16 September 1994 earthquake occur in the Taiwan Shoal region, outer rise of the Manila subduction zone. To understand what mechanisms control and generate the earthquake cluster, it is important to investigate the deep crustal structure of the Taiwan Shoal region. We present a 2-D seismic tomographic image of the crustal structure along the OBS2012 profile based on ocean bottom seismographic (OBS) data. The structure exhibits that a high velocity anomaly in the upper crust beneath the Taiwan Shoal is flanked by lower velocity anomalies. Based on the crustal structure, we study the 765 earthquakes, which occurred in the period 1991-2015. These epicenters, combined with the regional faults, and crustal structure, allow us to better understand the nature of the active tectonics in this region. The high velocity area is interpreted as representing stronger, defining major asperities where stress is concentrated corresponding to the location of the earthquake cluster. The earthquake cluster is influenced by the fault interactions. However, the 16 September 1994 earthquake is independents of the seismic activities but associated with the reactivation of the preexisting fault. In Taiwan region, the slab-pull was resisted by the exposed pre-collision accretionary prism and the resistive force caused the in-plane compressive stress accumulation. This condition may favor the triggering of future damaging earthquakes in this region. Key words: earthquake cluster; crustal structure; fault interactions; outer rise; Taiwan Shoal

  1. French Frigate Shoals Site P1A 11/1/2002 7-8M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 7 and 8 meters along a permanent transect.

  2. French Frigate Shoals Site P2 9/11/2002 15-16M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 15 and 16 meters along a permanent transect.

  3. French Frigate Shoals Site P16 10/4/2002 38-39M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 38 and 39 meters along a permanent transect.

  4. French Frigate Shoals Site P3 11/2/2002 29-30M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 29 and 30 meters along a permanent transect.

  5. French Frigate Shoals Site P1 7/14/2001 36-37M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1 (23.855N, 166.323W), between 36 and 37 meters along a permanent transect.

  6. French Frigate Shoals Site P2 7/15/2001 35-36M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 35 and 36 meters along a permanent transect.

  7. Evaluation of groundwater flow and transport at the Shoal underground nuclear test: An interim report

    Energy Technology Data Exchange (ETDEWEB)

    Pohll, G.; Chapman, J.; Hassan, A.; Papelis, C.; Andricevic, R.; Shirley, C.

    1998-07-01

    Since 1962, all United States nuclear tests have been conducted underground. A consequence of this testing has been the deposition of large amounts of radioactive materials in the subsurface, sometimes in direct contact with groundwater. The majority of this testing occurred on the Nevada Test Site, but a limited number of experiments were conducted in other locations. One of these is the subject of this report, the Project Shoal Area (PSA), located about 50 km southeast of Fallon, Nevada. The Shoal test consisted of a 12-kiloton-yield nuclear detonation which occurred on October 26, 1963. Project Shoal was part of studies to enhance seismic detection of underground nuclear tests, in particular, in active earthquake areas. Characterization of groundwater contamination at the Project Shoal Area is being conducted by the US Department of Energy (DOE) under the Federal Facility Agreement and Consent Order (FFACO) with the State of Nevada Department of Environmental Protection and the US Department of Defense (DOD). This order prescribes a Corrective Action Strategy (Appendix VI), which, as applied to underground nuclear tests, involves preparing a Corrective Action Investigation Plan (CAIP), Corrective Action Decision Document (CADD), Corrective Action Plan, and Closure Report. The scope of the CAIP is flow and transport modeling to establish contaminant boundaries that are protective of human health and the environment. This interim report describes the current status of the flow and transport modeling for the PSA.

  8. French Frigate Shoals Site P4 10/4/2002 7-8M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 7 and 8 meters along a permanent transect.

  9. French Frigate Shoals Site P3 7/16/2001 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 14 and 15 meters along a permanent transect.

  10. French Frigate Shoals Site P1A 9/13/2002 32-33M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 32 and 33 meters along a permanent transect.

  11. French Frigate Shoals Site P5 11/2/2002 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 14 and 15 meters along a permanent transect.

  12. French Frigate Shoals Site P1 7/14/2001 2-3M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1 (23.855N, 166.323W), between 2 and 3 meters along a permanent transect.

  13. French Frigate Shoals Site P16 10/4/2002 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 14 and 15 meters along a permanent transect.

  14. French Frigate Shoals Site P3 9/11/2002 6-7M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769N, 166.261W), between 6 and 7 meters along a permanent transect.

  15. French Frigate Shoals Site P3 9/11/2002 15-16M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769N, 166.261W), between 15 and 16 meters along a permanent transect.

  16. French Frigate Shoals Site P14 11/1/2002 21-22M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 21 and 22 meters along a permanent transect.

  17. French Frigate Shoals Site P14 11/1/2002 37-38M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 37 and 38 meters along a permanent transect.

  18. French Frigate Shoals Site P5 11/2/2002 16-17M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 16 and 17 meters along a permanent transect.

  19. French Frigate Shoals Site P16 10/4/2002 23-24M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 23 and 24 meters along a permanent transect.

  20. CRED Gridded Bathymetry of French Frigate Shoals (100-019) in the Northwestern Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — File 100-019b is a 60-m ASCII grid of depth data collected near French Frigate Shoals in the Northwestern Hawaiian Islands as of May 2003. This grid has been...

  1. French Frigate Shoals Site P3 7/16/2001 5-6M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 5 and 6 meters along a permanent transect.

  2. French Frigate Shoals Site P3 9/11/2002 11-12M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769N, 166.261W), between 11 and 12 meters along a permanent transect.

  3. French Frigate Shoals Site P11 10/30/2002 15-16M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 15 and 16 meters along a permanent transect.

  4. French Frigate Shoals Site P12 10/31/2002 1-2M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 1 and 2 meters along a permanent transect.

  5. French Frigate Shoals Site P16 9/14/2001 8-9M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 8 and 9 meters along a permanent transect.

  6. French Frigate Shoals Site P5 7/17/2001 36-37M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 36 and 37 meters along a permanent transect.

  7. French Frigate Shoals Site P12 10/31/2002 16-17M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 16 and 17 meters along a permanent transect.

  8. French Frigate Shoals Site P2 9/11/2002 11-12M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 11 and 12 meters along a permanent transect.

  9. French Frigate Shoals Site P5 11/2/2002 28-29M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 28 and 29 meters along a permanent transect.

  10. French Frigate Shoals Site P4 7/16/2001 8-9M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 8 and 9 meters along a permanent transect.

  11. French Frigate Shoals Site P5 11/2/2002 26-27M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 26 and 27 meters along a permanent transect.

  12. French Frigate Shoals Site P4 7/16/2001 10-11M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 10 and 11 meters along a permanent transect.

  13. French Frigate Shoals Site P5 11/2/2002 32-33M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 32 and 33 meters along a permanent transect.

  14. French Frigate Shoals Site P2 7/15/2001 27-28M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 27 and 28 meters along a permanent transect.

  15. French Frigate Shoals Site P4 10/4/2002 48-49M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 48 and 49 meters along a permanent transect.

  16. French Frigate Shoals Site P4 7/16/2001 28-29M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 28 and 29 meters along a permanent transect.

  17. French Frigate Shoals Site P12 10/31/2002 3-4M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 3 and 4 meters along a permanent transect.

  18. French Frigate Shoals Site P14 11/1/2002 26-27M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 26 and 27 meters along a permanent transect.

  19. French Frigate Shoals Site P5 11/2/2002 39-40M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 39 and 40 meters along a permanent transect.

  20. French Frigate Shoals Site P1A 11/1/2002 28-29M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 28 and 29 meters along a permanent transect.

  1. French Frigate Shoals Site P3 9/11/2002 4-5M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769N, 166.261W), between 4 and 5 meters along a permanent transect.

  2. French Frigate Shoals Site P1A 9/13/2002 49-50M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 49 and 50 meters along a permanent transect.

  3. French Frigate Shoals Site P16 9/14/2001 6-7M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 6 and 7 meters along a permanent transect.

  4. French Frigate Shoals Site P3 9/11/2002 12-13M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769N, 166.261W), between 12 and 13 meters along a permanent transect.

  5. French Frigate Shoals Site P4 7/16/2001 33-34M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 33 and 34 meters along a permanent transect.

  6. French Frigate Shoals Site P16 10/4/2002 37-38M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 37 and 38 meters along a permanent transect.

  7. French Frigate Shoals Site P5 11/2/2002 47-48M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 47 and 48 meters along a permanent transect.

  8. French Frigate Shoals Site P11 10/30/2002 32-33M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 32 and 33 meters along a permanent transect.

  9. French Frigate Shoals Site P1 7/14/2001 31-32M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1 (23.855N, 166.323W), between 31 and 32 meters along a permanent transect.

  10. French Frigate Shoals Site P16 10/4/2002 13-14M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 13 and 14 meters along a permanent transect.

  11. French Frigate Shoals Site P5 7/17/2001 3-4M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 3 and 4 meters along a permanent transect.

  12. French Frigate Shoals Site P16 9/14/2001 31-32M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 31 and 32 meters along a permanent transect.

  13. French Frigate Shoals Site P3 11/2/2002 3-4M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 3 and 4 meters along a permanent transect.

  14. French Frigate Shoals Site P13 10/31/2002 33-34M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 33 and 34 meters along a permanent transect.

  15. French Frigate Shoals Site P2 7/15/2001 16-17M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 16 and 17 meters along a permanent transect.

  16. French Frigate Shoals Site P5 7/17/2001 28-29M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 28 and 29 meters along a permanent transect.

  17. French Frigate Shoals Site P2 7/15/2001 10-11M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 10 and 11 meters along a permanent transect.

  18. French Frigate Shoals Site P4 10/4/2002 13-14M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 13 and 14 meters along a permanent transect.

  19. French Frigate Shoals Site P4 10/4/2002 37-38M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 37 and 38 meters along a permanent transect.

  20. French Frigate Shoals Site P5 7/17/2001 25-26M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 25 and 26 meters along a permanent transect.

  1. French Frigate Shoals Site P5 7/17/2001 13-14M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 13 and 14 meters along a permanent transect.

  2. French Frigate Shoals Site P13 10/31/2002 16-17M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 16 and 17 meters along a permanent transect.

  3. French Frigate Shoals Site P16 9/14/2001 23-24M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 23 and 24 meters along a permanent transect.

  4. French Frigate Shoals Site P1A 11/1/2002 23-24M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 23 and 24 meters along a permanent transect.

  5. French Frigate Shoals Site P5 7/17/2001 26-27M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 26 and 27 meters along a permanent transect.

  6. French Frigate Shoals Site P14 11/1/2002 5-6M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 5 and 6 meters along a permanent transect.

  7. French Frigate Shoals Site P13 10/31/2002 12-13M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 12 and 13 meters along a permanent transect.

  8. French Frigate Shoals Site P16 9/14/2001 18-19M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 18 and 19 meters along a permanent transect.

  9. French Frigate Shoals Site P4 7/16/2001 11-12M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 11 and 12 meters along a permanent transect.

  10. French Frigate Shoals Site P5 7/17/2001 2-3M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 2 and 3 meters along a permanent transect.

  11. French Frigate Shoals Site P4 10/4/2002 5-6M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 5 and 6 meters along a permanent transect.

  12. French Frigate Shoals Site P14 11/1/2002 20-21M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 20 and 21 meters along a permanent transect.

  13. French Frigate Shoals Site P12 10/31/2002 29-30M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 29 and 30 meters along a permanent transect.

  14. French Frigate Shoals Site P11 10/30/2002 30-31M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 30 and 31 meters along a permanent transect.

  15. French Frigate Shoals Site P16 9/14/2001 48-49M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 48 and 49 meters along a permanent transect.

  16. French Frigate Shoals Site P5 11/2/2002 33-34M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 33 and 34 meters along a permanent transect.

  17. French Frigate Shoals Site P4 10/4/2002 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 14 and 15 meters along a permanent transect.

  18. French Frigate Shoals Site P3 7/16/2001 3-4M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 3 and 4 meters along a permanent transect.

  19. Influence of Inlet / Shoal Complex on Adjacent Shorelines via Inlet Sink Method

    Science.gov (United States)

    2012-07-01

    placing dredged material onto adjacent beaches in moderate quantities (~200-500K cu yd) since the 1970 ’s (Dredging Information System (DIS...southward to Matanzas Inlet. Analysis of the ebb shoal volume change between surveys was made within a GIS framework using an area mask (Fig. 6

  20. French Frigate Shoals Site P14 11/1/2002 0-1M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 0 and 1 meters along a permanent transect.

  1. French Frigate Shoals Site P11 10/30/2002 46-47M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 46 and 47 meters along a permanent transect.

  2. French Frigate Shoals Site P11 10/30/2002 13-14M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 13 and 14 meters along a permanent transect.

  3. French Frigate Shoals Site P12 10/31/2002 8-9M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 8 and 9 meters along a permanent transect.

  4. French Frigate Shoals Site P12 10/31/2002 4-5M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 4 and 5 meters along a permanent transect.

  5. French Frigate Shoals Site P13 10/31/2002 17-18M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 17 and 18 meters along a permanent transect.

  6. French Frigate Shoals Site P4 10/4/2002 42-43M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 42 and 43 meters along a permanent transect.

  7. French Frigate Shoals Site P5 7/17/2001 8-9M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 8 and 9 meters along a permanent transect.

  8. French Frigate Shoals Site P2 7/15/2001 31-32M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 31 and 32 meters along a permanent transect.

  9. French Frigate Shoals Site P12 10/31/2002 11-12M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 11 and 12 meters along a permanent transect.

  10. French Frigate Shoals Site P11 10/30/2002 33-34M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 33 and 34 meters along a permanent transect.

  11. French Frigate Shoals Site P5 7/17/2001 10-11M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 10 and 11 meters along a permanent transect.

  12. French Frigate Shoals Site P4 7/16/2001 24-25M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 24 and 25 meters along a permanent transect.

  13. French Frigate Shoals Site P16 10/4/2002 11-12M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 11 and 12 meters along a permanent transect.

  14. French Frigate Shoals Site P3 11/2/2002 44-45M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 44 and 45 meters along a permanent transect.

  15. French Frigate Shoals Site P3 11/2/2002 23-24M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 23 and 24 meters along a permanent transect.

  16. French Frigate Shoals Site P14 11/1/2002 38-39M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 38 and 39 meters along a permanent transect.

  17. French Frigate Shoals Site P12 10/31/2002 23-24M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 23 and 24 meters along a permanent transect.

  18. French Frigate Shoals Site P3 11/2/2002 49-50M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 49 and 50 meters along a permanent transect.

  19. French Frigate Shoals Site P1 7/14/2001 0-1M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1 (23.855N, 166.323W), between 0 and 1 meters along a permanent transect.

  20. French Frigate Shoals Site P12 10/31/2002 28-29M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 28 and 29 meters along a permanent transect.

  1. French Frigate Shoals Site P5 11/2/2002 45-46M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 45 and 46 meters along a permanent transect.

  2. French Frigate Shoals Site P5 7/17/2001 40-41M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 40 and 41 meters along a permanent transect.

  3. French Frigate Shoals Site P4 7/16/2001 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 14 and 15 meters along a permanent transect.

  4. French Frigate Shoals Site P4 10/4/2002 40-41M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 40 and 41 meters along a permanent transect.

  5. French Frigate Shoals Site P16 10/4/2002 24-25M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 24 and 25 meters along a permanent transect.

  6. French Frigate Shoals Site P4 7/16/2001 38-39M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 38 and 39 meters along a permanent transect.

  7. French Frigate Shoals Site P4 10/4/2002 46-47M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 46 and 47 meters along a permanent transect.

  8. French Frigate Shoals Site P12 10/31/2002 26-27M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 26 and 27 meters along a permanent transect.

  9. French Frigate Shoals Site P5 11/2/2002 2-3M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 2 and 3 meters along a permanent transect.

  10. French Frigate Shoals Site P1A 11/1/2002 1-2M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 1 and 2 meters along a permanent transect.

  11. French Frigate Shoals Site P5 7/17/2001 31-32M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 31 and 32 meters along a permanent transect.

  12. French Frigate Shoals Site P11 10/30/2002 16-17M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 16 and 17 meters along a permanent transect.

  13. French Frigate Shoals Site P3 11/2/2002 30-31M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 30 and 31 meters along a permanent transect.

  14. French Frigate Shoals Site P14 11/1/2002 46-47M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 46 and 47 meters along a permanent transect.

  15. French Frigate Shoals Site P11 10/30/2002 48-49M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 48 and 49 meters along a permanent transect.

  16. French Frigate Shoals Site P12 10/31/2002 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 14 and 15 meters along a permanent transect.

  17. French Frigate Shoals Site P1A 11/1/2002 16-17M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 16 and 17 meters along a permanent transect.

  18. French Frigate Shoals Site P13 10/31/2002 7-8M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 7 and 8 meters along a permanent transect.

  19. French Frigate Shoals Site P4 10/4/2002 43-44M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 43 and 44 meters along a permanent transect.

  20. Response of Mediterranean circulation to Miocene shoaling and closure of the Indian Gateway : A model study

    NARCIS (Netherlands)

    De La Vara, Alba; Meijer, Paul

    2016-01-01

    In this regional ocean model study, we explore the effect of the Early to Middle Miocene shoaling and closure of the Indian Gateway on Mediterranean circulation and its exchange with the adjacent oceans. For this we use the regional ocean circulation model "sbPOM" and a collection of bathymetries cr

  1. French Frigate Shoals Site P1A 11/1/2002 39-40M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 39 and 40 meters along a permanent transect.

  2. French Frigate Shoals Site P14 11/1/2002 15-16M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 15 and 16 meters along a permanent transect.

  3. French Frigate Shoals Site P5 11/2/2002 19-20M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 19 and 20 meters along a permanent transect.

  4. French Frigate Shoals Site P4 7/16/2001 17-18M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 17 and 18 meters along a permanent transect.

  5. French Frigate Shoals Site P14 11/1/2002 24-25M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 24 and 25 meters along a permanent transect.

  6. French Frigate Shoals Site P1A 11/1/2002 41-42M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 41 and 42 meters along a permanent transect.

  7. French Frigate Shoals Site P1A 11/1/2002 32-33M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 32 and 33 meters along a permanent transect.

  8. French Frigate Shoals Site P5 11/2/2002 6-7M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 6 and 7 meters along a permanent transect.

  9. French Frigate Shoals Site P4 10/4/2002 45-46M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 45 and 46 meters along a permanent transect.

  10. French Frigate Shoals Site P16 9/14/2001 28-29M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 28 and 29 meters along a permanent transect.

  11. French Frigate Shoals Site P1A 11/1/2002 2-3M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 2 and 3 meters along a permanent transect.

  12. French Frigate Shoals Site P1A 11/1/2002 3-4M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 3 and 4 meters along a permanent transect.

  13. French Frigate Shoals Site P4 10/4/2002 27-28M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 27 and 28 meters along a permanent transect.

  14. French Frigate Shoals Site P4 10/4/2002 26-27M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 26 and 27 meters along a permanent transect.

  15. French Frigate Shoals Site P14 11/1/2002 16-17M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 16 and 17 meters along a permanent transect.

  16. French Frigate Shoals Site P12 10/31/2002 33-34M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 33 and 34 meters along a permanent transect.

  17. French Frigate Shoals Site P4 10/4/2002 33-34M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 33 and 34 meters along a permanent transect.

  18. French Frigate Shoals Site P14 11/1/2002 11-12M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 11 and 12 meters along a permanent transect.

  19. French Frigate Shoals Site P5 11/2/2002 20-21M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 20 and 21 meters along a permanent transect.

  20. French Frigate Shoals Site P12 10/31/2002 21-22M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 21 and 22 meters along a permanent transect.

  1. French Frigate Shoals Site P5 11/2/2002 8-9M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 8 and 9 meters along a permanent transect.

  2. French Frigate Shoals Site P14 11/1/2002 22-23M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 22 and 23 meters along a permanent transect.

  3. French Frigate Shoals Site P14 11/1/2002 13-14M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 13 and 14 meters along a permanent transect.

  4. French Frigate Shoals Site P11 10/30/2002 39-40M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 39 and 40 meters along a permanent transect.

  5. French Frigate Shoals Site P1 7/14/2001 32-33M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1 (23.855N, 166.323W), between 32 and 33 meters along a permanent transect.

  6. French Frigate Shoals Site P16 10/4/2002 18-19M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 18 and 19 meters along a permanent transect.

  7. French Frigate Shoals Site P4 10/4/2002 32-33M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 32 and 33 meters along a permanent transect.

  8. French Frigate Shoals Site P16 10/4/2002 9-10M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 9 and 10 meters along a permanent transect.

  9. French Frigate Shoals Site P14 11/1/2002 50-51M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 50 and 51 meters along a permanent transect.

  10. French Frigate Shoals Site P12 10/31/2002 15-16M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 15 and 16 meters along a permanent transect.

  11. French Frigate Shoals Site P1A 11/1/2002 9-10M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 9 and 10 meters along a permanent transect.

  12. French Frigate Shoals Site P1A 11/1/2002 5-6M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 5 and 6 meters along a permanent transect.

  13. French Frigate Shoals Site P4 7/16/2001 35-36M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 35 and 36 meters along a permanent transect.

  14. French Frigate Shoals Site P3 7/16/2001 9-10M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 9 and 10 meters along a permanent transect.

  15. French Frigate Shoals Site P3 11/2/2002 27-28M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 27 and 28 meters along a permanent transect.

  16. French Frigate Shoals Site P11 10/30/2002 35-36M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 35 and 36 meters along a permanent transect.

  17. French Frigate Shoals Site P11 10/30/2002 40-41M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 40 and 41 meters along a permanent transect.

  18. French Frigate Shoals Site P2 9/11/2002 0-1M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 0 and 1 meters along a permanent transect.

  19. French Frigate Shoals Site P1A 11/1/2002 42-43M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 42 and 43 meters along a permanent transect.

  20. French Frigate Shoals Site P4 7/16/2001 40-41M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 40 and 41 meters along a permanent transect.

  1. French Frigate Shoals Site P2 7/15/2001 18-19M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 18 and 19 meters along a permanent transect.

  2. French Frigate Shoals Site P16 9/14/2001 2-3M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 2 and 3 meters along a permanent transect.

  3. French Frigate Shoals Site P1A 11/1/2002 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 14 and 15 meters along a permanent transect.

  4. French Frigate Shoals Site P16 10/4/2002 6-7M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 6 and 7 meters along a permanent transect.

  5. French Frigate Shoals Site P4 10/4/2002 36-37M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 36 and 37 meters along a permanent transect.

  6. French Frigate Shoals Site P1A 11/1/2002 51-52M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 51 and 52 meters along a permanent transect.

  7. French Frigate Shoals Site P3 7/16/2001 33-34M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 33 and 34 meters along a permanent transect.

  8. French Frigate Shoals Site P3 11/2/2002 0-1M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 0 and 1 meters along a permanent transect.

  9. French Frigate Shoals Site P16 10/4/2002 30-31M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 30 and 31 meters along a permanent transect.

  10. French Frigate Shoals Site P2 7/15/2001 37-38M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 37 and 38 meters along a permanent transect.

  11. French Frigate Shoals Site P4 10/4/2002 9-10M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 9 and 10 meters along a permanent transect.

  12. French Frigate Shoals Site P3 11/2/2002 46-47M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 46 and 47 meters along a permanent transect.

  13. French Frigate Shoals Site P5 7/17/2001 32-33M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 32 and 33 meters along a permanent transect.

  14. French Frigate Shoals Site P3 11/2/2002 19-20M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 19 and 20 meters along a permanent transect.

  15. French Frigate Shoals Site P16 10/4/2002 1-2M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 1 and 2 meters along a permanent transect.

  16. French Frigate Shoals Site P4 7/16/2001 4-5M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 4 and 5 meters along a permanent transect.

  17. French Frigate Shoals Site P1 7/14/2001 11-12M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1 (23.855N, 166.323W), between 11 and 12 meters along a permanent transect.

  18. French Frigate Shoals Site P2 7/15/2001 36-37M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 36 and 37 meters along a permanent transect.

  19. French Frigate Shoals Site P16 10/4/2002 12-13M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 12 and 13 meters along a permanent transect.

  20. French Frigate Shoals Site P16 9/14/2001 4-5M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 4 and 5 meters along a permanent transect.

  1. French Frigate Shoals Site P14 11/1/2002 28-29M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 28 and 29 meters along a permanent transect.

  2. French Frigate Shoals Site P5 11/2/2002 46-47M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 46 and 47 meters along a permanent transect.

  3. French Frigate Shoals Site P1 7/14/2001 3-4M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1 (23.855N, 166.323W), between 3 and 4 meters along a permanent transect.

  4. French Frigate Shoals Site P5 11/2/2002 12-13M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 12 and 13 meters along a permanent transect.

  5. French Frigate Shoals Site P2 7/15/2001 15-16M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 15 and 16 meters along a permanent transect.

  6. French Frigate Shoals Site P14 11/1/2002 32-33M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 32 and 33 meters along a permanent transect.

  7. French Frigate Shoals Site P2 7/15/2001 9-10M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 9 and 10 meters along a permanent transect.

  8. French Frigate Shoals Site P1A 9/13/2002 48-49M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 48 and 49 meters along a permanent transect.

  9. French Frigate Shoals Site P13 10/31/2002 1-2M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 1 and 2 meters along a permanent transect.

  10. French Frigate Shoals Site P14 11/1/2002 39-40M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 39 and 40 meters along a permanent transect.

  11. French Frigate Shoals Site P13 10/31/2002 0-1M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 0 and 1 meters along a permanent transect.

  12. French Frigate Shoals Site P3 11/2/2002 35-36M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 35 and 36 meters along a permanent transect.

  13. French Frigate Shoals Site P16 10/4/2002 4-5M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 4 and 5 meters along a permanent transect.

  14. French Frigate Shoals Site P11 10/30/2002 31-32M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P11 (23.864N, 166.211W), between 31 and 32 meters along a permanent transect.

  15. French Frigate Shoals Site P16 9/14/2001 42-43M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 42 and 43 meters along a permanent transect.

  16. French Frigate Shoals Site P12 10/31/2002 13-14M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 13 and 14 meters along a permanent transect.

  17. French Frigate Shoals Site P4 7/16/2001 12-13M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 12 and 13 meters along a permanent transect.

  18. French Frigate Shoals Site P14 11/1/2002 35-36M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 35 and 36 meters along a permanent transect.

  19. French Frigate Shoals Site P4 10/4/2002 22-23M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 22 and 23 meters along a permanent transect.

  20. French Frigate Shoals Site P4 7/16/2001 31-32M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 31 and 32 meters along a permanent transect.

  1. French Frigate Shoals Site P2 7/15/2001 25-26M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 25 and 26 meters along a permanent transect.

  2. French Frigate Shoals Site P14 11/1/2002 10-11M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 10 and 11 meters along a permanent transect.

  3. French Frigate Shoals Site P4 10/4/2002 12-13M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 12 and 13 meters along a permanent transect.

  4. French Frigate Shoals Site P16 9/14/2001 47-48M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 47 and 48 meters along a permanent transect.

  5. French Frigate Shoals Site P3 11/2/2002 12-13M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 12 and 13 meters along a permanent transect.

  6. French Frigate Shoals Site P5 11/2/2002 27-28M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 27 and 28 meters along a permanent transect.

  7. French Frigate Shoals Site P5 11/2/2002 36-37M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 36 and 37 meters along a permanent transect.

  8. French Frigate Shoals Site P12 10/31/2002 30-31M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P12 (23.871N, 166.281 W), between 30 and 31 meters along a permanent transect.

  9. French Frigate Shoals Site P4 7/16/2001 37-38M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 37 and 38 meters along a permanent transect.

  10. French Frigate Shoals Site P13 10/31/2002 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 14 and 15 meters along a permanent transect.

  11. French Frigate Shoals Site P14 11/1/2002 30-31M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P14 (23.866 N, 166.290 W), between 30 and 31 meters along a permanent transect.

  12. French Frigate Shoals Site P1A 9/13/2002 44-45M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 44 and 45 meters along a permanent transect.

  13. French Frigate Shoals Site P16 9/14/2001 10-11M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 10 and 11 meters along a permanent transect.

  14. French Frigate Shoals Site P1A 9/13/2002 50-51M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 50 and 51 meters along a permanent transect.

  15. French Frigate Shoals Site P5 11/2/2002 9-10M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 9 and 10 meters along a permanent transect.

  16. French Frigate Shoals Site P5 11/2/2002 1-2M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 1 and 2 meters along a permanent transect.

  17. French Frigate Shoals Site P5 11/2/2002 24-25M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P5 (23.880 N, 166.273 W), between 24 and 25 meters along a permanent transect.

  18. French Frigate Shoals Site P1A 11/1/2002 30-31M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 30 and 31 meters along a permanent transect.

  19. French Frigate Shoals Site P2 7/15/2001 2-3M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 2 and 3 meters along a permanent transect.

  20. French Frigate Shoals Site P16 9/14/2001 33-34M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 33 and 34 meters along a permanent transect.

  1. French Frigate Shoals Site P3 7/16/2001 10-11M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 10 and 11 meters along a permanent transect.

  2. French Frigate Shoals Site P1A 11/1/2002 10-11M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P1A (23.854N, 166.323 W), between 10 and 11 meters along a permanent transect.

  3. French Frigate Shoals Site P4 7/16/2001 34-35M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P4 (23.864 N, 166.211 W), between 34 and 35 meters along a permanent transect.

  4. French Frigate Shoals Site P3 7/16/2001 26-27M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P3 (23.769 N, 166.261 W), between 26 and 27 meters along a permanent transect.

  5. French Frigate Shoals Site P16 9/14/2001 22-23M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 22 and 23 meters along a permanent transect.

  6. French Frigate Shoals Site P16 9/14/2001 27-28M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 27 and 28 meters along a permanent transect.

  7. French Frigate Shoals Site P16 9/14/2001 38-39M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 38 and 39 meters along a permanent transect.

  8. French Frigate Shoals Site P2 7/15/2001 14-15M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 14 and 15 meters along a permanent transect.

  9. French Frigate Shoals Site P2 7/15/2001 40-41M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 40 and 41 meters along a permanent transect.

  10. French Frigate Shoals Site P2 9/11/2002 13-14M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P2 (23.645N, 166.175W), between 13 and 14 meters along a permanent transect.

  11. French Frigate Shoals Site P16 10/4/2002 10-11M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P16 (23.857 N, 166.271 W), between 10 and 11 meters along a permanent transect.

  12. French Frigate Shoals Site P13 10/31/2002 21-22M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at French Frigate Shoals, site P13 (23.271 N, 166.284W), between 21 and 22 meters along a permanent transect.

  13. Building with Sand

    Science.gov (United States)

    Ashbrook, Peggy

    2010-01-01

    Children playing in damp sand invariably try to make a tower or a tunnel. By providing experiences with a variety of materials, alone and together, teachers set up the conditions for children to learn through their senses and ensure that a class approaches a topic with a common set of experiences to build on. Learning about the properties of…

  14. Faraday, Jets, and Sand

    NARCIS (Netherlands)

    Sandtke, M.; van der Meer, Roger M.; Versluis, Andreas Michel; Lohse, Detlef

    2003-01-01

    When a 6-mm layer of fine sand with an average grain size of 40 µm is poured into a cylindrical container and shaken vertically, thin jets are seen to emerge from an airy cloud of grains, almost like protuberances from the corona of the sun. A quasi two-dimensional setup reveals the jet-formation

  15. Building with Sand

    Science.gov (United States)

    Ashbrook, Peggy

    2010-01-01

    Children playing in damp sand invariably try to make a tower or a tunnel. By providing experiences with a variety of materials, alone and together, teachers set up the conditions for children to learn through their senses and ensure that a class approaches a topic with a common set of experiences to build on. Learning about the properties of…

  16. Virksomhedens sande ansigt

    DEFF Research Database (Denmark)

    Lundholt, Marianne Wolff

    2017-01-01

    Er modhistorier en byrde eller en styrke i forandringsprocesser? Hvad stiller vi op, når adgangen til organisationens sande identitet går gennem medarbejdernes modhistorier? Når vi sammenholder denne erkendelse med vores viden om, at medarbejdere helt naturligt afholder sig fra at videregive disse...

  17. Sand (CSW4)

    CSIR Research Space (South Africa)

    Estuarine and Coastal Research Unit

    1982-12-01

    Full Text Available This report is one of a series on Cape Estuaries being published under the general title "The Estuaries of the Cape, Part 2". The report provides information on sand estuary: historical background, abiotic and biotic characteristics. It is pointed...

  18. Ontogenetic changes in feeding and food preferences of the dog conch Laevistrombus canarium Linnaeus 1758 (Mollusca: Gastropoda) from Merambong shoal, Malaysia

    Science.gov (United States)

    Husna, Wan Nurul Wan Hassan; Mazlan, Abd Ghaffar; Cob, Zaidi Che

    2017-09-01

    Laevistrombus canarium is one of the marine gastropod mollusks that have high commercial value, particularly in the aquaculture sector in Malaysia. This study was conducted to determine the feeding and food items of L. canarium at different ontogenetic stages (juveniles, sub-adults and adults) from Merambong shoals, Malaysia. Field observations on feeding activity were conducted, followed by detailed laboratory analysis on the stomach content. Five-minutes observations on randomly selected individuals were conducted at the field sampling site and their feeding activities were recorded with reference to age stage. Various shell sizes from each ontogenetic stage were randomly collected and quickly anaesthetized with ice and preserved in 10% formalin before being transported to the laboratory for stomach content analyses. Field observations showed that L. canarium mainly grazed on epiphytes occurring on seagrass (46.67%), followed by sediment surface (40%) and epiphytes occurring on macroalgae (13.33%). Stomach content analyses showed a significant difference ( P Food items found in the conch stomach include diatoms, detritus, foraminifera, seagrass and macroalgae fragments, sand particles and shell fragments. The Index of Relative Importance (%IRI) indicates three main types of food dominated the three ontogenetic stages namely diatoms, sand particles and detritus. However, no significant difference ( P >0.05) was detected between the three main food items (diatoms, sand particles and detritus) among the ontogenetic stages. Therefore, feeding activity revealed the role of the dog conch in the marine food network. While, classification of the types of food consumed by L. canarium through stomach content analysis determines the particular position of the gastropod in the food chain. Further studies are needed to provide a better insight between trophic relationships of L. canarium with marine ecosystem.

  19. Ontogenetic changes in feeding and food preferences of the dog conch Laevistrombus canarium Linnaeus 1758 (Mollusca: Gastropoda) from Merambong shoal, Malaysia

    Science.gov (United States)

    Husna, Wan Nurul Wan Hassan; Mazlan, Abd Ghaffar; Cob, Zaidi Che

    2016-10-01

    Laevistrombus canarium is one of the marine gastropod mollusks that have high commercial value, particularly in the aquaculture sector in Malaysia. This study was conducted to determine the feeding and food items of L. canarium at different ontogenetic stages (juveniles, sub-adults and adults) from Merambong shoals, Malaysia. Field observations on feeding activity were conducted, followed by detailed laboratory analysis on the stomach content. Five-minutes observations on randomly selected individuals were conducted at the field sampling site and their feeding activities were recorded with reference to age stage. Various shell sizes from each ontogenetic stage were randomly collected and quickly anaesthetized with ice and preserved in 10% formalin before being transported to the laboratory for stomach content analyses. Field observations showed that L. canarium mainly grazed on epiphytes occurring on seagrass (46.67%), followed by sediment surface (40%) and epiphytes occurring on macroalgae (13.33%). Stomach content analyses showed a significant difference (P Food items found in the conch stomach include diatoms, detritus, foraminifera, seagrass and macroalgae fragments, sand particles and shell fragments. The Index of Relative Importance (%IRI) indicates three main types of food dominated the three ontogenetic stages namely diatoms, sand particles and detritus. However, no significant difference (P >0.05) was detected between the three main food items (diatoms, sand particles and detritus) among the ontogenetic stages. Therefore, feeding activity revealed the role of the dog conch in the marine food network. While, classification of the types of food consumed by L. canarium through stomach content analysis determines the particular position of the gastropod in the food chain. Further studies are needed to provide a better insight between trophic relationships of L. canarium with marine ecosystem.

  20. Erosion phenomena in sand moulds

    Directory of Open Access Journals (Sweden)

    A. Chojecki

    2008-03-01

    Full Text Available Authors studicd the erosion phcnorncna in sand moulds pured with cast iron. Thc study comprises an evaluation of erosionresistance of thc three sands: grccn sand. sand bondcd with inorganic or organic bindcr. It was concluded that thc most resistant is [heclassic green sand with thc addition of 5 B coal dust. Resistance of the sand with organic binder is generally weak and dcvnds onkind of used raisin. Spccinl nztcntion was paid to the sands with no organic bindcr watcr glass and phospha~c. It was Sound that thcirrcsistance depends on dehydratation conditions. When the mould is stored in law humidity of atmosphcrc the very strong crosion canbe expected. It rcsul ts hrn thc micro fractures in the bridges of binders, joining the grains of the sable. This phcnomcna facilitates thetearing away of fragments of sand [tom the surface

  1. A Three-Point Method for Separating Incident and Reflected Waves over A Sloping Bed

    Institute of Scientific and Technical Information of China (English)

    CHANG Hsien-Kuo

    2002-01-01

    This study presents a three-point method for separating incident and reflected waves to explain normally incident waves' propagating over a sloping bed. Linear wave shoaling is used to determine changes in wave amplitude and phase in response to variations of bathymetry. The wave reflection coefficient and incident amplitude are estimated from wave heights measured at three fixed wave gauges with unequal spacing. Sensitivity analysis demonstrates that the proposed method can predict the reflection and amplitude of waves over a sloping bed more accurately than the two-point method.

  2. On Pluvial Compaction of Sand

    DEFF Research Database (Denmark)

    Jacobsen, Moust

    At the Institute of Civil Engineering in Aalborg model tests on dry sand specimens have been carried out during the last five years. To reduce deviations in test results, the sand laying technique has been carefully studied, and the sand mass spreader constructed. Preliminary results have been...

  3. DISSIPATION OF WAVE ENERGY ON VERY MILD SLOPE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper presents the analysis and calculation of wave attenuation when waves travel on sand bed, sand ripple bed and muddy bed, respectively. The study shows that (1) The dissipation of wave energy due to bottom percolation may be neglected on sand bed; (2) The wave attenuation due to the friction of sand ripples is one order higher than that of flat sand bed and (3) The energy loss of waves propagating on muddy bed is the largest. Then, the equivalent coefficients of friction are calculated in order to compare with the solution by the bottom-friction model. Wave attenuation are also computed by the Bingham-model and the principle of conservation of wave energy flux on very mild muddy slope. The results coincide well with the wave information from the Lianyungang Wave Observation Station. Theoretical prediction proves that the equivalent coefficients of friction strongly rely on water depth, which inerease with decreasing depth.

  4. Assessment of Enterococcus Levels in Recreational Beach Sand Along the Rhode Island Coast.

    Science.gov (United States)

    Coakley, Eugenie; Parris, Amie L; Wyman, Al; Latowsky, Gretchen

    2016-04-01

    Recent studies have shown that coastal beach sand as well as coastal ocean water can be contaminated with fecal indicator Enterococcus bacteria (ENT). A study of sand ENT concentrations over a four-week period at 12 Rhode Island beaches was conducted during the summer of 2009. While average contamination was low relative to water quality standards, every beach had at least one day with very high sand ENT readings. On 10 of the 12 beaches, a statistically significant gradient occurred in geometric mean ENT concentrations among tidal zones, with dry (supratidal, or above high tide mark) sand having the highest level, followed by wet (intratidal, or below high tide mark) and underwater sand. Beaches with higher wave action had significantly lower ENT levels in wet and underwater sand compared to beaches with lower wave action.

  5. Analysis of seafloor change at Breton Island, Gosier Shoals, and surrounding waters, 1869–2014, Breton National Wildlife Refuge, Louisiana

    Science.gov (United States)

    Flocks, James G.; Terrano, Joseph F.

    2016-08-01

    Characterizing bathymetric change in coastal environments is an important component in understanding shoreline evolution, especially along barrier island platforms. Bathymetric change is a function of the regional sediment budget, long-term wave and current patterns, and episodic impact from high-energy events such as storms. Human modifications may also cause changes in seafloor elevation. This study, conducted by the U.S. Geological Survey in collaboration with the U.S. Fish and Wildlife Service, evaluates bathymetric and volumetric change and sediment characteristics around Breton Island and Gosier Shoals located offshore of the Mississippi River Delta in Louisiana. This area has been affected by significant storm events such as Hurricane Katrina in 2005. Sedimentation patterns at Breton Island and offshore have also been modified by the excavation of a shipping channel north of the island. Four time periods are considered that encompass these episodes and include long-term change and short-term storm recovery: 1869–2014, 1869–1920, 1920–2014, and 2007–2014. Finally, sediment characteristics are reported in the context of seafloor elevation.

  6. LARGE EDDY SIMULATION FOR PLUNGING BREAKER WAVE

    Institute of Scientific and Technical Information of China (English)

    Bai Yu-chuan; Wang Zhao-yin

    2003-01-01

    As wave propagates into shallow water, the shoaling effect leads to increase of wave height, and at a certain position, the wave will be breaking. The breaking wave is powerful agents for generating turbulence, which plays an important role in most of the fluid dynamical processes in the surf zone, so a proper numerical model for describing the turbulent effect is needed urgently. A numerical model is set up to simulate the wave breaking process, which consists of a free surface model using the surface marker method and the vertical two-dimensional model that solves the flow equations. The turbulence is described by Large Eddy Simulation (LES) method where the larger turbulent features are simulated by solving the flow equations, and the small-scale turbulence that is represented by a sub-grid model. A dynamic eddy viscosity sub-grid scale stress model has been used for the present simulation. The large eddy simulation model, which we presented in this paper, can be used to study the propagation of a solitary wave in constant water depth and the shoaling of a non-breaking solitary wave on a beach. To track free-surface movements, The TUMMAC method is employed. By applying the model to wave breaking problem in the surf zone, we found that these model results compared very well with experimental data. In addition, this model is able to reproduce the complicated flow phenomena, especially the plunging breaker.

  7. Sand hazards on tourist beaches.

    Science.gov (United States)

    Heggie, Travis W

    2013-01-01

    Visiting the beach is a popular tourist activity worldwide. Unfortunately, the beach environment is abundant with hazards and potential danger to the unsuspecting tourist. While the traditional focus of beach safety has been water safety oriented, there is growing concern about the risks posed by the sand environment on beaches. This study reports on the death and near death experience of eight tourists in the collapse of sand holes, sand dunes, and sand tunnels. Each incident occurred suddenly and the complete burial in sand directly contributed to the victims injury or death in each case report.

  8. PROCESSING OF MONAZITE SAND

    Science.gov (United States)

    Calkins, G.D.; Bohlmann, E.G.

    1957-12-01

    A process for the recovery of thorium, uranium, and rare earths from monazite sands is presented. The sands are first digested and dissolved in concentrated NaOH, and the solution is then diluted causing precipitation of uranium, thorium and rare earth hydroxides. The precipitate is collected and dissolved in HCl, and the pH of this solution is adjusted to about 6, precipitating the hydroxides of thorium and uranium but leaving the rare earths in solution. The rare earths are then separated from the solution by precipitation at a still higher pH. The thorium and uranium containing precipitate is redissolved in HNO/sub 3/ and the two elements are separated by extraction into tributyl phosphate and back extraction with a weakly acidic solution to remove the thorium.

  9. Application Documents for the Cape Wind Associates, LLC, Horseshoe Shoal, Nantucket Sound (Offshore Renewable Energy Project/OCS Air Permit)

    Science.gov (United States)

    List of application documents for the Cape Wind Associates, LLC, Horseshoe Shoal, Nantucket Sound (Offshore Renewable Energy Project/OCS Air Permit: Massachusetts Plan Approval including nonattainment NSR Appendix A requirements).

  10. Comments for the Cape Wind Associates, LLC, Horseshoe Shoal, Nantucket Sound (Offshore Renewable Energy Project/OCS Air Permit)

    Science.gov (United States)

    List of comments for the Cape Wind Associates, LLC, Horseshoe Shoal, Nantucket Sound (Offshore Renewable Energy Project/OCS Air Permit: Massachusetts Plan Approval including nonattainment NSR Appendix A requirements).

  11. Shallow-water Marine Invertebrates French Frigate Shoals, Northwestern Hawaiian Islands 2000 and 2002, (NODC Accession 0001083)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset focuses on marine surveys used to obtain a more in depth record of the marine fauna from French Frigate Shoals and includes a note on nonindigenous...

  12. Nantucket Shoals Flux Experiment, Data Report I, Hydrography; 04 October 1976 to 19 November 1985 (NODC Accession 8700242)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Nantucket Shoals Flux Experiment (1979 - 1980) was a multi-institutional effort to measure the flux of shelf water along the continental shelf south of Nantucket...

  13. Moving sand dunes

    CERN Document Server

    Sparavigna, Amelia Carolina

    2011-01-01

    In several desert areas, the slow motion of sand dunes can be a challenge for modern human activities and a threat for the survival of ancient places or archaeological sites. However, several methods exist for surveying the dune fields and estimate their migration rate. Among these methods, the use of satellite images, in particular of those freely available on the World Wide Web, is a convenient resource for the planning of future human settlements and activities.

  14. Velocity flow field and water level measurements in shoaling and breaking water waves

    CSIR Research Space (South Africa)

    Mukaro, R

    2010-01-01

    Full Text Available and creates micro-environments for the small creatures that form the basis for life in the oceans. For the above Seventh South African Conference on Computational and Applied Mechanics SACAM10 Pretoria, 10?13 January 2010 ? SACAM 2 reasons...

  15. Leadership emergence in a data-driven model of zebrafish shoals with speed modulation

    Science.gov (United States)

    Zienkiewicz, A.; Barton, D. A. W.; Porfiri, M.; Di Bernardo, M.

    2015-11-01

    Models of collective animal motion can greatly aid in the design and interpretation of behavioural experiments that seek to unravel, isolate, and manipulate the determinants of leader-follower relationships. Here, we develop an initial model of zebrafish social behaviour, which accounts for both speed and angular velocity regulatory interactions among conspecifics. Using this model, we analyse the macroscopic observables of small shoals influenced by an "informed" agent, showing that leaders which actively modulate their speed with respect to their neighbours can entrain and stabilise collective dynamics of the naïve shoal. Supplementary material in the form of two mp4 files available from the Journal web page at http://dx.doi.org/10.1140/epjst/e2015-50093-5

  16. Multiple S-isotopic evidence for episodic shoaling of anoxic water during Late Permian mass extinction.

    Science.gov (United States)

    Shen, Yanan; Farquhar, James; Zhang, Hua; Masterson, Andrew; Zhang, Tonggang; Wing, Boswell A

    2011-02-22

    Global fossil data show that profound biodiversity loss preceded the final catastrophe that killed nearly 90% marine species on a global scale at the end of the Permian. Many hypotheses have been proposed to explain this extinction and yet still remain greatly debated. Here, we report analyses of all four sulphur isotopes ((32)S, (33)S, (34)S and (36)S) for pyrites in sedimentary rocks from the Meishan section in South China. We observe a sulphur isotope signal (negative δ(34)S with negative Δ(33)S) that may have resulted from limitation of sulphate supply, which may be linked to a near shutdown of bioturbation during shoaling of anoxic water. These results indicate that episodic shoaling of anoxic water may have contributed to the profound biodiversity crisis before the final catastrophe. Our data suggest a prolonged deterioration of oceanic environments during the Late Permian mass extinction.

  17. Seafloor integrity down the harbor waterfront: the coralligenous shoals off Vado Ligure (NW Mediterranean

    Directory of Open Access Journals (Sweden)

    Giulia Gatti

    2012-06-01

    Full Text Available In the last ten years, European Directives stressed the necessity to assess the ecological status of marine habitats by means of ecosystem or landscape indicators, rather than just species or chemical ones. In this paper, the seascape approach to characterise and assess the ecological quality of coralligenous rocky shoals of Vado Ligure (Savona, Italy is introduced. This approach integrates biological, mesological and geomorphological information collected with a Rapid Visual Assessment technique (RVA. The RVA also optimised underwater operations in deep waters where coralligenous reefs usually develop and provided a sufficient amount of data collected by direct inspection. The seascape approach results are appropriate for the characterisation of the coralligenous shoals studied and for the assessment of their ecological quality. The quality of the assemblages was in general low, mainly due to high sedimentary stress; however, some exceptions showing a high ecological quality indicate that, with proper manage- ment tools, they would still have good potentialities of recovery.

  18. Interactions between aggression, boldness and shoaling within a brood of convict cichlids (Amatitlania nigrofasciatus).

    Science.gov (United States)

    Moss, Sarah; Tittaferrante, Stephanie; Way, Gregory P; Fuller, Ashlei; Sullivan, Nicole; Ruhl, Nathan; McRobert, Scott P

    2015-12-01

    A behavioral syndrome is considered present when individuals consistently express correlated behaviors across two or more axes of behavior. These axes of behavior are shy-bold, exploration-avoidance, activity, aggression, and sociability. In this study we examined aggression, boldness and sociability (shoaling) within a juvenile convict cichlid brood (Amatitlania nigrofasciatus). Because young convict cichlids are social, we used methodologies commonly used by ethologists studying social fishes. We did not detect an aggression-boldness behavioral syndrome, but we did find that the aggression, boldness, and possibly the exploration behavioral axes play significant roles in shaping the observed variation in individual convict cichlid behavior. While juvenile convict cichlids did express a shoaling preference, this social preference was likely convoluted by aggressive interactions, despite the small size and young age of the fish. There is a need for the development of behavioral assays that allow for more reliable measurement of behavioral axes in juvenile neo-tropical cichlids.

  19. Sand Resources and Geological Character of Long Island Sound.

    Science.gov (United States)

    1981-05-01

    Ashraf (1973a, 1973b), Coch (1974), and Williams (1976) identified deeply buried stream channels which are pre-Pleistocene but acted as conduits for...Migration of Sand Waves in a Large Estuary, Long Island Sound," Marine Geology, Vol. 24, 1977, pp. 185-199. COCH , N., "Morphology and Sediment

  20. Advancements in the U.S. Army Corps of Engineers Hydrographic Survey Capabilities: The SHOALS System

    Science.gov (United States)

    2016-05-12

    Advancements in the U.S. Army Corps of Engineers Hydrographic Survey Capabilities: The SHOALS System JEFF LILLYCROP U.S. Army Corps...the U. S. Army Corps of Engineers has undertaken a joint development program with Canada to construct and field test an operational prototype...hydrographic survey, airborne lidar. Introduction The U.S. Army Corps of Engineers is responsible for surveying over 40,000 kilometers of federally

  1. Earth-strength magnetic field affects the rheotactic threshold of zebrafish swimming in shoals.

    Science.gov (United States)

    Cresci, Alessandro; De Rosa, Rosario; Putman, Nathan F; Agnisola, Claudio

    2017-02-01

    Rheotaxis, the unconditioned orienting response to water currents, is a main component of fish behavior. Rheotaxis is achieved using multiple sensory systems, including visual and tactile cues. Rheotactic orientation in open or low-visibility waters might also benefit from the stable frame of reference provided by the geomagnetic field, but this possibility has not been explored before. Zebrafish (Danio rerio) form shoals living in freshwater systems with low visibility, show a robust positive rheotaxis, and respond to geomagnetic fields. Here, we investigated whether a static magnetic field in the Earth-strength range influenced the rheotactic threshold of zebrafish in a swimming tunnel. The direction of the horizontal component of the magnetic field relative to water flow influenced the rheotactic threshold of fish as part of a shoal, but not of fish tested alone. Results obtained after disabling the lateral line of shoaling individuals with Co(2+) suggest that this organ system is involved in the observed magneto-rheotactic response. These findings constitute preliminary evidence that magnetic fields influence rheotaxis and suggest new avenues for further research.

  2. Continuous wide area monitoring of fish shoaling behavior with acoustic waveguide sensing and bioclutter implications

    Science.gov (United States)

    Makris, Nicholas C.; Ratilal, Purnima; Symonds, Deanelle T.; Nero, Redwood W.

    2001-05-01

    Field measurements are used to show that the detailed behavior of fish shoals can be continuously monitored at roughly 1-min intervals over wide areas spanning hundreds of square kilometers by long range acoustic waveguide sensing. The technique was used on the New Jersey Continental Shelf to produce unprecedented video images of shoal formation, fragmentation, and migration. Simultaneous line-transect measurements show the imaged shoals to contain pelagic fish with densities of at least one individual per meter3. The technique relies upon acoustic waveguide propagation in the continental shelf. Here, trapped modes dominate propagation and suffer only cylindrical spreading loss rather than the spherical loss suffered in free-space transmission or short-range propagation in the ocean. In contrast, standard methods for fish surveyance involve line transect measurements from slow moving research vessels that significantly under-sample fish distributions in time and space, leaving an incomplete behavioral picture. The implications of this bioclutter phenomenon on the Navy's long range active sonar operations in continental shelf environments are discussed.

  3. Evaluation of dredged material proposed for ocean Disposal from Shoal Harbor/Compton Creek Project Area

    Energy Technology Data Exchange (ETDEWEB)

    Gardiner, W.W.; Borde, A.B.; Nieukirk, S.L.; Barrows, E.S.; Gruendell, B.D.; Word, J.Q.

    1996-10-01

    The objective of the Shoal Harbor/Compton Creek Project was to evaluate proposed dredged material from the Shoal harbor/Compton Creek Project Area in Belford and Monmouth, New Jersey to determine its suitability for unconfined ocean disposal at the Mud Dump Site. This was one of five waterways that the US Army Corps of Engineers- New York District requested the Battelle Marine Sciences Laboratory (MSL) to sample and evaluate for dredging and disposal in May 1995. The evaluation of proposed dredged material from the Shoal Harbor/Compton Creek Project area consisted of bulk chemical analyses, chemical analyses of dredging site water and elutriate, benthic and water-column acute toxicity tests and bioaccumulation studies. Eleven core samples were analyzed or grain size, moisture content, and total organic carbon. Other sediments were evaluated for bulk density, specific gravity, metals, chlorinated pesticides, polychlorinated biphenyl (PCB) congers, polynuclear aromatic hydrocarbons, and 1,4- dichlorobenzene. Dredging site water and elutriate water were analyzed for metals, pesticides, and PCBs.

  4. Feasibility of Acoustic Remote Sensing of Large Herring Shoals and Seafloor by Baleen Whales

    Directory of Open Access Journals (Sweden)

    Dong Hoon Yi

    2016-08-01

    Full Text Available Recent research has found a high spatial and temporal correlation between certain baleen whale vocalizations and peak herring spawning processes in the Gulf of Maine. These vocalizations are apparently related to feeding activities with suggested functions that include communication, prey manipulation, and echolocation. Here, the feasibility of the echolocation function is investigated. Physical limitations on the ability to detect large herring shoals and the seafloor by acoustic remote sensing are determined with ocean acoustic propagation, scattering, and statistical theories given baleen whale auditory parameters. Detection is found to be highly dependent on ambient noise conditions, herring shoal distributions, baleen whale time-frequency vocalization spectra, and geophysical parameters of the ocean waveguide. Detections of large herring shoals are found to be physically feasible in common Gulf of Maine herring spawning scenarios at up to 10 ± 6 km in range for humpback parameters and 1 ± 1 km for minke parameters but not for blue and fin parameters even at zero horizontal range. Detections of the seafloor are found to be feasible up to 2 ± 1 km for blue and humpback parameters and roughly 1 km for fin and minke parameters, suggesting that the whales share a common acoustic sensation of rudimentary features of the geophysical environment.

  5. Compressive behavior of fine sand.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Bradley E. (Air Force Research Laboratory, Eglin, FL); Kabir, Md. E. (Purdue University, West Lafayette, IN); Song, Bo; Chen, Wayne (Purdue University, West Lafayette, IN)

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  6. Sand dollar sites orogenesis

    Science.gov (United States)

    Amos, Dee

    2013-04-01

    The determinology of the humble sand dollars habitat changing from inception to the drastic evolution of the zone to that of present day. Into the cauldron along the southern Californian 'ring of fire' lithosphere are evidence of geosynclinals areas, metasedimentary rock formations and hydrothermal activity. The explanation begins with 'Theia' and the Moon's formation, battles with cometary impacts, glacial ages, epochs with evolutionary bottlenecks and plate tectonics. Fully illustrated the lecture includes localised diagrams and figures with actual subject photographic examples of plutonic, granitic, jade and peridodite. Finally, the origins of the materials used in the lecture are revealed for prosecution by future students and the enjoyment of interested parties in general.

  7. Sand Storms Trigger Alarm

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ After an unusually humid winter with at least 10 snowfalls in Beijing, a severe andstorm blown by strong winds bringing with it thousands of tons of desert sand took many residents of the city by surprise.On the morning of March 20, Beijingers woke up to see clouds of yellow dust in the air and a sky that was an ominous orange in color.The loose soil and dust that had traveled htmdreds of miles from deserts in Mongolia and China's northwest blanketed Beijing's streets, covering parked vehicles, bikes, roofs and even plant life,as well as making its way into people's homes.

  8. Fortune Cookie Sand Dunes

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-432, 25 July 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a field of small barchan sand dunes in the north polar region near 71.7oN, 51.3oW. Some of them are shaped like fortune cookies. The message these dunes provide: winds blow through this region from the lower right toward the upper left. The steep slip face slopes of these dunes, which point toward the upper left, indicate the wind direction. The scene is illuminated by sunlight from the upper right. The image is 3 km (1.9 mi) wide.

  9. Numerical study on water waves and wave-induced longshore currents in Obaköy coastal water

    Institute of Scientific and Technical Information of China (English)

    TANG Jun; LYU Yigang; SHEN Yongming

    2014-01-01

    In this paper, the water waves and wave-induced longshore currents in Obaköy coastal water which is lo-cated at the Mediterranean coast of Turkey were numerically studied. The numerical model is based on the parabolic mild-slope equation for coastal water waves and the nonlinear shallow water equation for the wave-induced currents. The wave transformation under the effects of shoaling, refraction, diffraction and breaking is considered, and the wave provides radiation stresses for driving currents in the model. The numerical results for the water wave-induced longshore currents were validated by the measured data to demonstrate the efficiency of the numerical model. Then the water waves and longshore currents induced by the waves from main directions were numerically simulated and analyzed based on the numerical re-sults. The numerical results show that the movement of the longshore currents was different while the wave propagated to a coastal zone from different directions.

  10. A family of sand automata

    CERN Document Server

    Faulkner, Nicholas

    2012-01-01

    We study some dynamical properties of a family of two-dimensional cellular automata: those that arise from an underlying one dimensional sand automaton whose local rule is obtained using a latin square. We identify a simple sand automaton G whose local rule is algebraic, and classify this automaton as having equicontinuity points, but not being equicontinuous. We also show it is not surjective. We generalise some of these results to a wider class of sand automata.

  11. Dilatometric Characterization of Foundry Sands

    Directory of Open Access Journals (Sweden)

    M. Břuska

    2012-04-01

    Full Text Available The goal of this contribution is summary of physical – chemistry properties of usually used foundry silica and no – silica sands in Czech foundries. With the help of dilatometry analysis theoretical assumptions of influence of grain shape and size on dilatation value of sands were confirmed. Determined was the possibility of dilatometry analysis employment for preparing special (hybrid sands with lower and/or more linear character of dilatation.

  12. Triaxial tests in Fontainebleau sand

    DEFF Research Database (Denmark)

    Latini, Chiara; Zania, Varvara

    2016-01-01

    The purpose of this internal report is to examine the influence of relative density on the strength and deformation characteristics of Fontainebleau sand. Compression triaxial tests were performed on saturated sand samples with different densities and initial confining pressure. Note that the tes......The purpose of this internal report is to examine the influence of relative density on the strength and deformation characteristics of Fontainebleau sand. Compression triaxial tests were performed on saturated sand samples with different densities and initial confining pressure. Note...... that the testing procedure and the data processing were carried out according to the specifications of ETCS-F1.97....

  13. Geometry and dynamics of wave ripples in the nearshore zone of a coarse sandy beach

    Science.gov (United States)

    Masselink, G.; Austin, M. J.; O'Hare, T. J.; Russell, P. E.

    2007-10-01

    Extensive measurements of ripple characteristics and dynamics along with associated suspended sediment fluxes and hydrodynamic conditions were made in the shoaling and surf zones of a macrotidal coarse grained beach at Sennen Cove, Cornwall, England (median grain diameter 0.69 mm). Suborbital vortex ripples were observed during the majority of the study period with height ˜5 cm and length ˜35 cm. The scale and shape of the ripples did not vary significantly as the bed shear stress increased during wave shoaling and breaking. However, ripple migration rates (onshore directed) were strongly dependent on their location relative to the breakpoint, increasing from ˜0.1 cm min-1 under shoaling waves to 2 cm min-1 in the outer surf zone during low-energy conditions. Farther inside the surf zone, ripples persisted but migration rates slowed, probably owing to the presence of the offshore-directed mean flow which impedes landward migration of the ripples. Under low-wave conditions (during which measured sediment fluxes peaked around the outer surf zone and decreased through the saturated surf zone), bed form transport rates under shoaling waves were of the same magnitude as net suspended sediment fluxes but at least an order of magnitude smaller in the outer surf zone. Under high-energy conditions (during which suspended sediment fluxes in the surf zone were offshore directed owing to the presence of the seaward directed mean flow), bed form transport rates were several orders of magnitude smaller than suspended fluxes.

  14. Pullout capacity of batter pile in sand.

    Science.gov (United States)

    Nazir, Ashraf; Nasr, Ahmed

    2013-03-01

    Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21-31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18-75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  15. Pullout capacity of batter pile in sand

    Directory of Open Access Journals (Sweden)

    Ashraf Nazir

    2013-03-01

    Full Text Available Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21–31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18–75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  16. Sand Fences in the Coastal Zone: Intended and Unintended Effects

    Science.gov (United States)

    Grafals-Soto, Rosana; Nordstrom, Karl

    2009-09-01

    Sand-trapping fences modify the character of the coastal landscape and change its spatial structure, image, and meaning. This paper examines the relationship between these changes and fence usage at the municipal level, where most decisions about fence deployment are made. Use of fences in 29 municipalities on the developed coast of New Jersey is examined over a 6-year period. Interviews with municipal officers indicate that wooden slat sand-trapping fences are used primarily to build dunes to provide protection against wave uprush and flooding, but they are also used to control pedestrian traffic and demarcate territory. These uses result in changes in landforms and habitats. An aerial video inventory of fences taken in 2002 indicates that 82% of the shoreline had fences and 72% had dunes. Single and double straight fence rows are the most commonly used. Fences are often built to accomplish a specific primary purpose, but they can cause many different and often unanticipated changes to the landscape. The effects of a sand fence change through time as the initial structure traps sand, creates a dune that is colonized by vegetation, and becomes integrated into the environment by increasing topographic variability and aesthetic and habitat value. Sand fences can be made more compatible with natural processes by not placing them in locations where sources of wind blown sand are restricted or in unnatural shore perpendicular orientations. Symbolic fences are less expensive, are easy to replace when damaged, are less visually intrusive, and can be used for controlling pedestrian access.

  17. Hyperbolic Mild Slope Equations with Inclusion of Amplitude Dispersion Effect: Regular Waves

    Institute of Scientific and Technical Information of China (English)

    JIN Hong; ZOU Zhi-li

    2008-01-01

    A new form of hyperbolic mild slope equations is derived with the inclusion of the amplitude dispersion of nonlinear waves. The effects of including the amplitude dispersion effect on the wave propagation are discussed. Wave breaking mechanism is incorporated into the present model to apply the new equations to surf zone. The equations are solved numerically for regular wave propagation over a shoal and in surf zone, and a comparison is made against measurements. It is found that the inclusion of the amplitude dispersion can also improve model's performance on prediction of wave heights around breaking point for the wave motions in surf zone.

  18. The Relationship Between Shoreline Change and Surf Zone Sand Thickness

    Science.gov (United States)

    Miselis, J. L.; McNinch, J. E.

    2002-12-01

    There is a lack of information concerning surf zone geologic processes and their relationship to shoreline behavior despite the consensus that the two are intimately linked. Variations in sand thickness over a highly irregular migration surface close to the shoreline may influence wave dynamics and sediment transport and thus may be connected to hotspot formation. A nearshore survey, spanning 40km from north of the USACE-FRF pier in Duck, NC to just north of Oregon Inlet, was conducted using an interferometric swath bathymetry system and a chirp sub-bottom profiler. The study was conducted within 1km of the shore (in the surf zone) to investigate the processes that may be responsible for the behavior of shoreline hotspots in the area. The topmost reflector and the seafloor of the seismic profile were digitized and the depth difference between them was calculated. Though no ground truths were done in the survey area, cores collected from just north of the site suggest that the topmost reflector is a pre-modern ravinement surface (cohesive muds with layers of sand and gravel) upon which the Holocene sands migrate. An isopach map was generated and shows that the layer of sand above the first sub-bottom reflector is very thin and in some places, exposed. There are many variables that may influence hotspot behavior, including bar position and wave conditions, however, the purpose of this study is to determine if there is a spatial correlation between a thin or absent (exposed reflector) nearshore sand layer and the presence of a shoreline hotspot. In an area associated with a hotspot approximately 14km south of the USACE-FRF pier in Duck, the maximum thickness of Holocene sands was less than 2.5m. The average thickness was less than 1m (0.705m). Thicknesses that were less than 0.2m were classified as areas where the reflector was exposed and accounted for 5 percent of those calculated. It seems the thin layer of sand may represent a deficient nearshore sand source

  19. Namibia : triaxial test on sand

    DEFF Research Database (Denmark)

    Steenfelt, Jørgen S.; Jacobsen, Kim P.

    In connection with a harbour project the friction angle of a fine sand is required. On Friday 13 March 1998 the Danish Geotechnical Institute (DGI) delivered app. 2.5 kg sand for testing at the Geotechnical Engineering Laboratory, Aalborg University. The present Data Report summarises the results...

  20. 2010 oil sands performance report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    With the depletion of traditional energy resources and the rising demand for energy, oil sands have become an important energy resource for meeting energy needs. Oil sands are a mixture of water, sand, clay and bitumen which is recovered either through open pit mining or in situ drilling techniques. The bitumen is then converted into syncrude or sold to refineries for the production of gasoline, diesel or other products. Shell has oil sands operations in Alberta and the aim of this report is to present its 2010 performance in terms of CO2, water, tailings, land, and reclamation and engagement. This document covers several of Shell's operations in the Muskeg River and Jackpine mines, Scotford upgrader, Peace River, Orion, Seal, Cliffdale and Chipmunk. It provides useful information on Shell's oil sands performance to governments, environmental groups, First Nations, local communities and the public.