scholarly journals TIDAL SEDIMENTATION IN GROS-CACOUNA HARBOR

1978 ◽  
Vol 1 (16) ◽  
pp. 120 ◽  
Author(s):  
Georges Drapeau ◽  
Guy Fortin
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediments ◽  
Suspended Sediment Transport ◽  
Lawrence Estuary ◽  
Seismic Profiling ◽  
Reflection Seismic ◽  
High Turbidity ◽  
South Shore ◽  
Bottom Sampling ◽  
St Lawrence Estuary

The harbor of Gros-Cacouna on the South shore of the St. Lawrence Estuary has been silting at the rate of 31 cm/yr. since it was dredged at the depth of 14 meters in 1968. Measurements of temperature, salinity, turbidity, current speed and direction were carried out as well as bottom sampling and reflection seismic profiling. A model of suspended sediment transport combines the tidal volumes and the current profiles at the harbor entrance. During a period of high turbidity (Spring) in the St.Lawrence Estuary, 54.2 tons of suspended sediments entered the harbor during the flood phase, while 41.1 tons were carried out during the ebb phase of a semi-diurnal tide, leaving 13.1 tons of sediments in the harbor. The transfer coefficient is 0.24 indicating that one quarter of the suspended sediment load settles in the harbor during one tidal cycle. In September, the turbidity is low in the Estuary and the suspended sediment budget in the harbor is 4 times smaller but the ratio of deposited sediments versus the total quantity of sediments transported in suspension is the same.

scholarly journals Suspended Sediment Analysis: Case Study of Berounka Sources

Geografie ◽  
1997 ◽  
Vol 102 (2) ◽  
pp. 130-138
Author(s):  
Zdeněk Kliment ◽  
Jan Kopp
Keyword(s):  
Seasonal Variation ◽  
Sediment Transport ◽  
Suspended Sediment ◽  
Inorganic Material ◽  
Suspended Sediments ◽  
Suspended Load ◽  
Suspended Sediment Transport ◽  
Sediment Analysis ◽  
Load Characteristics

The article examines suspended sediment transport in Mže, Radbuza, and Úhlava Rivers over the period 1989-95. Data on suspended sediments was collected at five observing sites. The research has been carried out in collaboration with Czech Hydrometeorological Institute, Plzeň. Apart from the suspended load characteristics also the seasonal variation of suspended sediments, siltation of Hracholusky and České Údolí Lakes, and the share of inorganic material in suspended sediments have been examined.

Numerical Computation of Suspended Sediment Around a Marine Pipeline Close to the Flat Seabed

2011 ◽  
Author(s):  
Muk Chen Ong ◽  
Lars Erik Holmedal ◽  
Dag Myrhaug
Keyword(s):  
Suspended Sediment ◽  
Settling Velocity ◽  
Suspended Sediments ◽  
Navier Stokes ◽  
Suspended Sediment Transport ◽  
Flow Simulations ◽  
Reynolds Number Flow ◽  
Normal Distance ◽  
Number Flow ◽  
High Reynolds

The purpose of this paper is to investigate suspended sediment transport around a marine pipeline near the seabed by solving the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations with the standard k-ε model. High Reynolds number flow simulations are considered in the present study. The suspended sediments are seeded upstream of the pipeline. Particle trajectories of the suspended sediments downstream of the pipeline have been visualized by using a Lagrangian approach. Effects of the gap (i.e. the normal distance between the pipeline and the seabed) and the sediment weight (i.e. taking into account sediment settling velocity) have been investigated and discussed.

scholarly journals La mer de Goldthwait au Québec

2010 ◽  
Vol 31 (1-2) ◽  
pp. 61-80 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Quebec City ◽  
The South ◽  
Lawrence Estuary ◽  
Marine Invasion ◽  
North Shore ◽  
The North ◽  
Upper Limit ◽  
South Shore ◽  
Anticosti Island ◽  
St Lawrence Estuary

The Goldthwait Sea is defined as the late- and post-Glacial marine invasion in the St. Lawrence Estuary and Gulf east of Québec City. In Québec, this sea has submerged an area of about 25 000 km2. The largest areas submerged are the north shore of the St. Lawrence between Les Escoumins and Blanc-Sablon, the south shore between Levis and Tourelles, and the Anticosti Island. The upper limit of the Goldthwait Sea varies from place to place. The Goldthwait Sea began 14 000 years ago and land emergence is still in progress, since the pre-Wisconsin marine level has not been recovered yet. For a better chronology, this long interval needs to be subdivided. Three main periods have been recognized: Goldthwaitian I, II and III. However, a geographical subdivision is also needed. Numerous shorelines were observed at various elevations throughout the area formely submerged by the Goldthwait Sea. However, only a few shorelines are well developed and extensive, and correlations between former shorelines are difficult to establish. Only three levels are widespead and common to the Estuary and parts of the Gulf. The isostatic recovery has been rapid during the first three thousand years after déglaciation of the area: about 75%.

The food and feeding of common eiders in the St. Lawrence estuary in summer

1974 ◽  
Vol 52 (3) ◽  
pp. 319-334 ◽  
Author(s):  
M. Cantin ◽  
J. Bédard ◽  
H. Milne
Keyword(s):  
Intertidal Zone ◽  
Maximum Growth ◽  
Somateria Mollissima ◽  
Lawrence Estuary ◽  
Common Eiders ◽  
Feeding Activities ◽  
Food And Feeding ◽  
South Shore ◽  
Natural Foods ◽  
St Lawrence Estuary

The study was conducted in the St. Lawrence estuary during 1969 and 1970. The food abundance in the intertidal zone was measured in four Sampling stations located on the south shore of the river; the measurements revealed that over 95% of the available food of the common eider (Somateria mollissima) consisted of Littorina spp., Mytilus edulis, and Gammarus oceanicus. Both adult and young birds showed a distinct rhythm of feeding activities associated with tidal level. During the prenesting period, herring eggs and Nereis virens made up most of the food of adult common eiders. When accompanying ducklings, females ate mostly Littorina spp. and amphipods. Littorina spp. made up between 30 and 97% of the diet of the ducklings, the importance of this gastropod growing with age of the bird. Energy requirements during maximum growth were evaluated at about 460 kcal/bird per day on ducklings (age 54 days) fed natural foods, while between week 3 and week 8 it stood at about 520 kcal/bird per day in ducklings fed "turkey starter." These figures were used to assess the importance of the food removed by the eiders from the intertidal zone during the summer. We conclude that between 10 and 30% (according to the area) of the standing-crop biomass of Littorina alone (in July) is removed by the ducklings and the females accompanying them. At various moments through the season, these birds remove between 40 and 100 metric tons of mollusks per day from the intertidal zone.

scholarly journals Indirect Estimation of Flow and Suspended-sediment Concentration and Load in Small Mountain Streams: an Exploratory Study in Ribeira Seca Stream, Madeira Island

2021 ◽  
Vol 16 ◽  
Keyword(s):  
Suspended Sediment ◽  
Exploratory Study ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Suspended Sediment Transport ◽  
Measurement Campaign ◽  
Indirect Determination ◽  
Madeira Island ◽  
The North

The aim of this study was to assess the applicability of indirect techniques for streamflow and suspended sediment concentration estimation and their use in the calculation of suspended sediment transport rate in the small mountain watersheds of Madeira Island, Portugal. Emphasis was given to the application of salt dilution gauging to the indirect determination of the flow rate and the use of water turbidity data to estimate the concentration of suspended sediments. The field and laboratory work carried out are briefly described, and the main experimental results and the field data from the short measurement campaign performed in the Ribeira Seca stream in Faial, on the north side of the island, are presented and discussed. Whilst the measurement campaign carried out was temporally and spatially limited, it was pioneering for Madeira and allowed to verify the applicability of the indirect hydrometric and sedimentometric techniques used in this exploratory study.

Observations in the turbidity maximum of the St. Lawrence Estuary

1979 ◽  
Vol 16 (4) ◽  
pp. 939-950 ◽  
Author(s):  
Norman Silverberg ◽  
Bjørn Sundby
Keyword(s):  
Bottom Sediments ◽  
Suspended Matter ◽  
Detailed Examination ◽  
Lawrence Estuary ◽  
The North ◽  
Suspended Particulate ◽  
High Turbidity ◽  
St Lawrence Estuary ◽  
Maximum Turbidity Zone ◽  
Maximum Turbidity

A series of 13 and 25 h anchor stations and individual stations were occupied along the axis of the North Channel of the St. Lawrence Estuary during periods of both high and low river runoff. The data collected have permitted a detailed examination of the variations in salinity, suspended matter concentrations, and the size distributions of the suspended matter and the bottom sediments of the maximum turbidity zone. The high turbidity appears to be maintained by a complex density-driven circulation in combination with the resuspension of bottom sediments near the head of the estuary. The phenomenon may be aided by the breaking of internal waves. A longitudinal structure, which is only slightly influenced by changes in river discharge, is discernible for the zone. The highest concentrations of suspended matter occur in a well mixed region at the head of the estuary and suspended particulate matter levels decrease seaward as a two-layer estuarine circulation becomes better developed.

Suspended Sediment Transport and Deposition Modeling in the Bay of Fundy, Nova Scotia — a Region of Potential Tidal Power Development

1983 ◽  
Vol 40 (S1) ◽  
pp. s20-s34 ◽  
Author(s):  
D. A. Greenberg ◽  
C. L. Amos
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Gulf Of Maine ◽  
Suspended Sediments ◽  
Open Boundary ◽  
Suspended Sediment Transport ◽  
Bay Of Fundy ◽  
Tidal Power ◽  
Tidal Model ◽  
Critical Stresses

Two recent independent studies of the Minas Basin have been combined to produce a numerical simulation of suspended sediments. One study devised a numerical, barotropic tidal model of the Bay of Fundy and Gulf of Maine, which produced a good simulation of the tides and currents in the Minas Basin. The second, an extensive program of sediment sampling and monitoring addressed the nature of suspended sediments, bottom sediments, their various sediment sources and the postglacial evolution of the system. The only significant source of suspended sediment was from the open boundary to the Minas Basin and was of relatively uniform concentration through the water column. Consequently, the barotropic tidal model was well suited to modeling this material. Sediment laws describing sediment settling, resuspension, and the critical stress for entrainment were obtained from the literature and evaluated. The settling velocity of the suspended sediment was obtained by experimentation using actual water/sediment samples. Because the various parameters and critical stresses show a considerable variation among experimenters, runs were planned to examine a range of parameters. A close fit to existing conditions was obtained with the model generating mudflats in those regions where indeed they exist. Using the various parameters and critical stresses reflecting maximum sedimentation, the model was run to include the effects of a tidal power barrage off Economy Point. It is concluded that suspended sediment would not inhibit the operation of such a barrage through siltation directly in front of or behind the barrier. Increased siltation can be expected in the intertidal areas behind the barrage. Sediment budget considerations further limit the degree of post barrier siltation, insofar as the resident volume of suspended material (30 × 106 m3) is not enough to significantly reduce the headpond area.Key words: suspended sediment, sediment transport, numerical model, tide

scholarly journals Densité agricole et charge humaine des terroirs : Essai méthodologique avec application à quatre comtés au sud de l’estuaire du Saint-Laurent

2005 ◽  
Vol 9 (17) ◽  
pp. 11-23
Author(s):  
Jean Raveneau
Keyword(s):  
Physical Environment ◽  
Population Based ◽  
Population Pressure ◽  
Direct Proportion ◽  
Lawrence Estuary ◽  
Real Population ◽  
Two Factors ◽  
Part Time ◽  
South Shore ◽  
St Lawrence Estuary

The density of agricultural population based on cleared land does not necessarily express the real population pressure in a given agricultural region. Two factors can upset the significance of this measure of density : (1) differences in the intensity of exploitation within a single territory ; and (2), variations in the proportion of part-time farmers. The author bas developed an index of the pressure of population on the land by making various calculations for jour counties in Québec, on the south shore of the St. Lawrence estuary. He bas found that the population pressure on the land varies in nearly direct proportion to the agricultural density based on cleared land, in spite of the lack of uniformity of the physical environment in question. The author concludes that the agricultural density retains its validity for expressing the population pressure on the land.

Mud Cracks and Polygons on Ice Push Ridges, in Tidal Flats of the St. Lawrence Estuary

1974 ◽  
Vol 11 (3) ◽  
pp. 489-494 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Water Level ◽  
Tidal Flats ◽  
The South ◽  
Lawrence Estuary ◽  
Waves And Currents ◽  
South Shore ◽  
Break Up ◽  
St Lawrence Estuary

Mud cracks and polygons form during summer in tidal flats of the south shore of the St. Lawrence Estuary. They occur near mean low water level at the top surface of ice push mud ridges formed during winter and break-up. They are a source of mud clasts which settle in the surroundings when carried away by waves and currents.

Sign in / Sign up

Export Citation Format

Share Document