scholarly journals ACCURACY OF HYDROGRAPHIC SURVEYING IN AND NEAR THE SURF ZONE

2000 ◽  
Vol 1 (3) ◽  
pp. 3
Author(s):  
Thorndike Saville, Jr. ◽  
Joseph M. Caldwell
Keyword(s):  
Surf Zone ◽  
Average Rate ◽  
Significant Degree ◽  
Beach Erosion ◽  
Littoral Drift ◽  
Depth Measurement ◽  
Average Change ◽  
Sand Movement ◽  
Quantitative Changes ◽  
Dominant Direction

The analysis and solution of most beach erosion problems are based to a significant degree on the quantitative changes in the bottom hydrography as observed in successive surveys. Critical decisions as to the dominant direction of littoral drift, the average rate of this drift, and the onshore-offshore movement of material are based largely on such hydrographic surveys. As the net changes between successive surveys are usually small compared to the area being studied, the degree of accuracy or comparability of the hydrographic surveys is of considerable importance. For instance, a net change of 100,000 cubic yards over one square mile of beach represents an average change in depth of only about 0.1 feet. Thus, it can be seen that uncompensated errors in depth measurement of as little as 0.1 feet can produce indications of significant littoral sand movement which might not exist in reality.

scholarly journals APPLICATION OF FLUORESCENT COATED SAND IN LITTORAL DRIFT AND INLET STUDIES

1968 ◽  
Vol 1 (11) ◽  
pp. 19 ◽  
Author(s):  
Minze Stuiver ◽  
J.A. Purpura
Keyword(s):  
Coastal Engineering ◽  
Beach Erosion ◽  
Tracer Study ◽  
Littoral Drift ◽  
Sand Movement ◽  
Protective Structures ◽  
Coated Sand

The use of fluorescent coated sand In tracing the sand movement along beaches and around Inlets is an important tool in the field of Coastal Engineering. As a part of an extensive beach erosion study along the shore of West Palm Beach, Florida, four areas were subjected to such a "tracer study." Each area represented a particular beach configuration either with or without erosion protective structures. In this paper the procedure and results for one area is described. As a second application of sand tracers, the results of a study concerned with the sand migration in and around South Lake Worth Inlet is discussed.

scholarly journals BEACH CHANGE AROUND DETACHED BREAKWATERS DUE TO ARTIFICIAL NOURISHMENT OF BYPASSED SAND

1986 ◽  
Vol 1 (20) ◽  
pp. 115 ◽  
Author(s):  
H. Suyama ◽  
T. Uda ◽  
T. Yoshimura
Keyword(s):  
Field Experiment ◽  
Bottom Topography ◽  
Tracer Tests ◽  
Littoral Drift ◽  
Spatial Changes ◽  
Toyama Bay ◽  
Concrete Blocks ◽  
Sand Movement ◽  
Temporal And Spatial ◽  
Artificial Nourishment

Field experiment of sand bypassing was conducted on the Shimoni—ikawa Coast in Toyama Bay. The materials of 5900 m3 dredged on the updrift coast of the harbor were thrown into behind the detached breakwater. After the nourishment detailed surveys of the bottom topography around the breakwaters, wave observations and tracer tests using colored concrete blocks were carried out in order to investigate the movement of the nourished sand. Temporal and spatial changes of the shoreline positions and the sectional area of the beach in the shoreward zone of the detached breakwater are examined. It is found through the field experiment that the materials nourished behind the detached breakwater were carried slowly in the longshore direction by the westward littoral drift, dominating on the coast, without the outflow of sand through the openings of the breakwaters. It is concluded that the detached breakwater is useful to control the on—offshore sand movement and to retain the sand behind the detached breakwater.

scholarly journals SLED SYSTEM FOR PROFILING SUSPENDED LITTORAL DRIFT

1978 ◽  
Vol 1 (16) ◽  
pp. 106 ◽  
Author(s):  
J.P. Coakley ◽  
H.A. Savile ◽  
M. Pedrosa ◽  
M. Larocque
Keyword(s):  
Great Lakes ◽  
Surf Zone ◽  
Research Literature ◽  
Littoral Drift ◽  
Virtual Absence ◽  
Fast Ice ◽  
Steep Waves ◽  
Sled System ◽  
Coastal Research

There are many factors which suggest that littoral zone processes in the Great Lakes differ substantially from those of the marine coasts described in the existing coastal research literature. Among these factors are the lack of an appreciable tidal cycle; the predominance of relatively short, steep, waves; the virtual absence of swell waves; and the presence of shore fast ice in winter. As a result, many of the empirical relationships derived for marine coasts might be of questionable applicability to Great Lakes coasts. The present study, which represents only one phase of a long-term project designed to develop more specific littoral transport relationships, is aimed at obtaining accurate, direct estimates of the actual littoral transport at an experimental site located at the western end of Lake Ontario. This paper will describe a mechanical system designed to collect a series of time-averaged samples of suspended sediment for concentration determinations as well as flow velocity and water depth at locations across the surf zone. Some preliminary results of the field program using the system will also be presented and discussed.

scholarly journals BATHYMETRY INVERSION IN THE SURF ZONE VIA ASSIMILATION OF REMOTELY SENSED WAVE BREAKING ENERGY DISSIPATION

2020 ◽  
pp. 26
Author(s):  
Francisco Soto ◽  
Patricio Catalan
Keyword(s):  
Wave Breaking ◽  
Surf Zone ◽  
Remote Sensing Data ◽  
Depth Measurement ◽  
Unique Data ◽  
Uncertain Model ◽  
Data Source ◽  
Breaking Energy ◽  
Spurious Signals

In this work, a data assimilation approach treating bathymetry as an uncertain model parameter, is introduced where direct dissipation estimates from remote sensing data are the unique data source. Two dimensional wave breaking dissipation fields are retrieved on a wave-by-wave basis with the algorithms of Daz et al. (2018), who were able to reliably estimate breaking dissipation by removing spurious signals affecting electro-optical and microwave data. After a six hour application, the system was able to retrieve improved bathymetric estimates, without any in situ depth measurement. A prominent feature of this approach is its ability to reliably capture the amplitude and position of nearshore sandbars.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/Y7mgiSvmRYc

scholarly journals Conformational change in individual enzyme molecules

2015 ◽  
Vol 93 (6) ◽  
pp. 611-618 ◽  
Author(s):  
Jeremie J. Crawford ◽  
Frannie Itzkow ◽  
Joanna MacLean ◽  
Douglas B. Craig
Keyword(s):  
Heat Shock ◽  
Electrophoretic Mobility ◽  
Conformational Changes ◽  
Average Rate ◽  
Electrophoretic Mobilities ◽  
Significant Difference ◽  
Average Change ◽  
Before And After ◽  
Enzyme Molecules ◽  
Individual Enzyme

Single β-galactosidase molecule assays were performed using a capillary electrophoresis based protocol, employing post-column laser-induced fluorescence detection. In a first set of experiments, the distribution of single β-galactosidase molecule catalytic rates and electrophoretic mobilities were determined from lysates of Escherichia coli strains containing deletions for different heat shock proteins and grown under normal and heat shock conditions. There was no clear observed pattern of effect of heat shock protein expression on these distributions. In a second set of experiments, individual enzyme molecule catalytic rates were determined at 21 °C before and after 2 sequential brief periods of incubation at 50, 28, and 10 °C. The brief incubations at 50 °C caused a change in the enzyme molecules resulting in a different catalytic rate. Any given molecule was just as likely to show an increase in rate as a decrease, resulting in no significant difference in the average rate of the population. The average change in individual molecule rate was dependent upon the temperature of the brief incubation period, with a lesser average change occurring at 28 °C and negligible change at 10 °C. A third set of experiments was similar to that of the second with the exception that it was electrophoretic mobility that was considered. This provided a similar result. Incubation at higher temperature resulted in a change in electrophoretic mobility. The probability of an individual molecules switching to a higher mobility was approximately equal to that of switching to a lower mobility, resulting in no net average change in the population. The magnitude of the changes in electrophoretic mobilities suggest that the associated conformational changes are subtle.

scholarly journals PHYSICAL MODELLING OF BEACH EROSION AND LITTORAL DRIFT

1988 ◽  
Vol 1 (21) ◽  
pp. 134 ◽  
Author(s):  
Otavio J. Sayao ◽  
Robert B. Nairn
Keyword(s):  
Grain Size ◽  
Physical Model ◽  
Scale Effects ◽  
Physical Modelling ◽  
Beach Erosion ◽  
Model Design ◽  
Littoral Drift ◽  
Sedimentary Processes ◽  
Dynamic Similarity ◽  
Proposed Model

A new procedure for physical modelling of beach sedimentary processes is presented. It is shown that the modelling requirements proposed by Dean (1985) are necessary but not sufficient for dynamic similarity. Quantification of scale effects due to slope and relative grain size scaling conditions enables extrapolation of the physical model results to prototype situations. Selected examples of the application of the proposed model design are also given.

scholarly journals A Class of Probability Models for Littoral Drift

1970 ◽  
Vol 1 (12) ◽  
pp. 52
Author(s):  
William R. James
Keyword(s):  
Average Rate ◽  
Accurate Method ◽  
Sediment Flux ◽  
Transport Rate ◽  
Constant Thickness ◽  
Burial Depth ◽  
Tracer Transport ◽  
Probability Models ◽  
Littoral Drift ◽  
Tracer Concentration

The major goal in the development of sediment tracer technology is to produce an accurate method for the field measurement of short term volume littoral rate Many of the technical difficulties involved in tagging, injecting, and sensing the movement of radioisotope sand tracers in the littoral zone have been overcome by the RIST project However, quantitative determination of volume drift rate requires more than knowledge of tracer position in time and space A mathematical model is required to relate the flux of tracer material to the sediment flux A linear (or average) rate of tracer transport along the coastline can be measured to a fair degree of accuracy with tracers These measurements, when determined from tracers injected along a line source which span the transport zone, can be used to provide an estimate of an areal transport rate However, it is not obvious how to measure the third dimension, depth of transport This, of course, is needed to provide the desired estimate of volume transport rate This problem arises, even if the relation of tracer concentration to burial depth is everywhere known without error Sediment transport does not occur as a sheet of constant thickness moving at a constant rate If this were so tracer concentration would rapidly attain a uniform concentration over a fixed depth and no tracers would appear below that depth In fact no observations of the relation between tracer concentration and burial depth support this model as even a first approximation Studies such as those of Courtois and Monaco (1969) and Hubble and Sayre (1964) suggest that the concentration of tracers is related to burial depth in a complex fashion The concentration on the surface is finite, but not maximal The concentration increases with depth to some point where a maximum is reached and diminishes in a "long tailed" fashion.

scholarly journals Three-dimensional modelling of wave-induced current from the surf zone to the inner shelf

2011 ◽  
Vol 8 (6) ◽  
pp. 2417-2478 ◽  
Author(s):  
H. Michaud ◽  
P. Marsaleix ◽  
Y. Leredde ◽  
C. Estournel ◽  
F. Bourrin ◽  
...  
Keyword(s):  
Surf Zone ◽  
Transport Model ◽  
Spatial Scales ◽  
Three Dimensional ◽  
Circulation Model ◽  
Good Representation ◽  
Depth Range ◽  
Littoral Drift ◽  
Inner Shelf ◽  
The Impact

Abstract. We develop and implement a new method to take into account the impact of waves into the 3-D circulation model SYMPHONIE (Marsaleix et al., 2008, 2009a), following the simplified equations of Bennis et al. (2011) which use glm2z-RANS theory (Ardhuin et al., 2008b). These adiabatic equations are completed by additional parameterizations of wave breaking, bottom friction and wave-enhanced vertical mixing, making the forcing valid from the surf zone through to the open ocean. The wave forcing is performed by wave generation and propagation models WAVEWATCH III® (Tolman, 2008, 2009; Ardhuin et al., 2010) and SWAN (Booij et al., 1999). The model is tested and compared with other models for a plane beach test case, previously tested by Haas and Warner (2009) and Uchiyama et al. (2010). A comparison is also made with the laboratory measurements of Haller et al. (2002) of a barred beach with channels. Results fit with previous simulations performed by other models and with available observational data. Finally, a realistic case of energetic waves travelling over a coast of the Gulf of Lion (in the northwest of the Mediterranean Sea) for which currents are available at different depths as well as an accurate bathymetric database of the 0–10 m depth range, is then simulated. A grid nesting approach is used to account for the different forcings acting at different spatial scales. The simulation coupling the effects of waves and currents is successful to reproduce the powerful northward littoral drift in the 0–15 m depth zone. More precisely, two distinct cases are identified: when waves have a normal angle of incidence with the coast, they are responsible for complex circulation cells and rip currents in the surf zone, and when they travel obliquely, they generate a northward littoral drift. These features are more complicated than in the test cases, due to the complex bathymetry and the consideration of wind and non-stationary processes. Wave impacts in the inner shelf are less visible since wind and regional circulation seem to be the predominant forcings. Besides, a discrepancy between model and observations is noted at that scale, possibly linked to an underestimation of the wind stress. Lastly, this three-dimensional method allows a good representation of vertical current profiles and permits to calculate the shear stress associated with wave and current. Future work will focus on the combination with a sediment transport model.

scholarly journals MODE AND PERIOD OF SAND TRANSPORT IN THE SURF ZONE

1974 ◽  
Vol 1 (14) ◽  
pp. 47 ◽  
Author(s):  
Benno M. Brenninkmeyer
Keyword(s):  
Deep Water ◽  
Water Wave ◽  
Surf Zone ◽  
Sediment Concentration ◽  
Sand Transport ◽  
Bed Load ◽  
Measuring Devices ◽  
Load Movement ◽  
Sand Movement ◽  
Deep Water Wave

Three almometers-water opacity measuring devices-emplaced perpendicular to the beach, measure instantaneously and continuously the sediment concentration across the surf zone. Most of the variance of the sand movement is centered in frequencies of less than 0.25 Hz and between 1.15 and 1.25 Hz. Modes and frequency of sand transport differ within each of the dynamic zones of the surf. The motion of sediment in the inner and outer surf zones is small and virtually independent of the deep water wave periods. Outside the breaker zone, bed load movement is somewhat coincident with the prevailing swell period. Lighter concentrations move predominantly with a 0.8-0.9 second periodicity. In the breaker zone, sand moves along the bottom with frequencies equal to that of both the swell and sea, but most of the power is in lower frequencies. In the breaker zone sand is rarely thrown into suspension. In the transition zone, sediment motion is largely by suspension with a period a little longer than the swell.

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