Tidal-current control of submarine morphology at the mouth of the Miramichi estuary, New Brunswick

1977 ◽  
Vol 14 (11) ◽  
pp. 2524-2532 ◽  
Author(s):  
G. E. Reinson
Keyword(s):  
New Brunswick ◽  
Tidal Current ◽  
Barrier Island ◽  
Current Control ◽  
Tidal Range ◽  
Tidal Prism ◽  
Artificial Channel ◽  
Ebb Tidal Delta ◽  
Island System ◽  
Natural Channel

The mouth of the microtidal Miramichi estuary, New Brunswick, is enclosed by a barrier-island system which is cut by two major tidal inlets. The submarine morphology adjacent to these inlets indicates the presence of large tidal deltas which formed predominantly by tidal-current processes. The extensive shoal water on the landward side of the barrier is due to the landward transport of sand through the inlets and the deposition of this sand as coalescing flood-tidal delta deposits. The creation of an artificial channel inside the main inlet in the late 19th century, and its maintenance since that time, have resulted in substantial channel-flow bypassing of the natural channel seaward of the barrier. This promoted the scouring of a new channel through the ebb-tidal delta shoal.Large tidal deltas apparently are not common morphological features of estuaries on microtidal, barrier-island coastlines, but they do occur at the entrances of very large microtidal estuaries such as the Miramichi. In such cases they are usually completely subtidal, and much larger than tidal deltas of mesotidal estuaries reported in the literature. Rather than tidal range, the tidal prism, which takes into account both tidal range and estuary surface area, may play the major role in the formation of tidal deltas in both mesotidal and microtidal estuaries.

scholarly journals SEDIMENTATION PROCESSES ALONG THE EAST FRIESIAN ISLANDS, WEST GERMANY

1984 ◽  
Vol 1 (19) ◽  
pp. 203 ◽  
Author(s):  
Duncan M. FitzGerald ◽  
Shea Penland ◽  
Dag Nummedal
Keyword(s):  
Barrier Island ◽  
High Energy ◽  
Tidal Flats ◽  
Main Channel ◽  
West Germany ◽  
Tidal Range ◽  
Erosion And Deposition ◽  
Longshore Sediment Transport ◽  
Longshore Transport ◽  
Ebb Tidal Delta

The East Friesian Islands are located on a high energy shoreline. The average deepwater significant wave height exceeds 1.0 m and the spring tidal range varies from 2.7 to 2.9 m. A large easterly net longshore transport rate has caused eastward growth of the barrier islands. Reclamation of tidal flats has significantly reduced the backbarrier area and has resulted in a decrease in the ratio of inlet width to barrier island length from 42% to 16% during the past 300 years. The headwaters of the major channel dissecting the tidal flats erode in an eastward direction in response to tidal and wave driven currents, wave suspension, and eastward barrier island elongation. Consequently, the drainage systems of most of the inlets are highly asymmetric with 70-80% of the tidal prism coming from the east. This pattern results in a hooked main channel. The location of the channel at the inlet throat is controlled by the westward ebb flow in the main channel, the inertia of ebb flow in the tributary creeks, eastward longshore sediment transport, and the regional stratigraphy. The position and orientation of the main ebb channel controls the symmetry of the ebb-tidal delta about the inlet shoreline. This, in turn, affects the location of swash bar attachment to the beach and overall trends of erosion and deposition along the downdrift barrier.

scholarly journals BEACH CHANGES AND WAVE CONDITIONS, NEW BRUNSWICK

1972 ◽  
Vol 1 (13) ◽  
pp. 65
Author(s):  
S. Brian McCann ◽  
Edward A. Bryant
Keyword(s):  
New Brunswick ◽  
Barrier Island ◽  
Energy System ◽  
Wave Refraction ◽  
Additional Information ◽  
Coastal Province ◽  
Wave Trains ◽  
Wave Conditions ◽  
Island System ◽  
Realistic Appraisal

The coast line of Kouchibouguac Bay, New Brunswick, within the southern Gulf of St. Lawrence coastal province, consists of a barrier island system of sand beaches and low dunes. It is a relatively low energy system in a protected location with the important waves entering the bay through a narrow fetch window from the northeast. The behaviour of these wave trains and their refraction patterns within the S. Gulf of St. Lawrence and Kouchibouguac Bay were simulated by the construction of a series of refraction diagrams, from which it is possible to obtain a realistic appraisal of wave conditions at the shore. Waves entering the bay from N and NE directions are concentrated on the southern part of the barrier island system,, and those entering from the ENE and E are concentrated on the northern part. In greater detail, a series of wave refraction diagrams, based on former conditions of nearshore bathymetry at Richiboucto Inlet, help to explain the changes which have occurred there in the past 80 years. The simulation of wave behaviour in Kouchibouguac Bay has provided useful additional information which helps to explain the recent evolution of the barrier island system.

scholarly journals Morphodynamic Evolution of a Nourished Beach with Artificial Sandbars: Field Observations and Numerical Modeling

2021 ◽  
Vol 9 (3) ◽  
pp. 245
Author(s):  
Cuiping Kuang ◽  
Xuejian Han ◽  
Jiabo Zhang ◽  
Qingping Zou ◽  
Boling Dong
Keyword(s):  
Sediment Transport ◽  
Tidal Current ◽  
Model Simulation ◽  
Morphological Changes ◽  
Current Model ◽  
Beach Nourishment ◽  
Tidal Range ◽  
Coastal Protection ◽  
Field Observations ◽  
One Year

Beach nourishment, a common practice to replenish an eroded beach face with filling sand, has become increasingly popular as an environmentally friendly soft engineering measure to tackle coastal erosion. In this study, three 200 m long offshore submerged sandbars were placed about 200 m from the shore in August 2017 for both coastal protection and beach nourishment at Shanhai Pass, Bohai Sea, northeastern China. A series of 21 beach profiles were collected from August 2017 to July 2018 to monitor the morphological changes of the nourished beach. Field observations of wave and tide levels were conducted for one year and tidal current for 25 h, respectively. To investigate the spatial-temporal responses of hydrodynamics, sediment transport, and morphology to the presence of three artificial submerged sandbars, a two-dimensional depth-averaged (2DH) multi-fraction sediment transport and morphological model were coupled with wave and current model and implemented over a spatially varying nested grid. The model results compare well with the field observations of hydrodynamics and morphological changes. The tidal range was around 1.0 m and the waves predominately came from the south-south-east (SSE) direction in the study area. The observed and predicted beach profiles indicate that the sandbars moved onshore and the morphology experienced drastic changes immediately after the introduction of sandbars and reached an equilibrium state in about one year. The morphological change was mainly driven by waves. Under the influences of the prevailing waves and the longshore drift toward the northeast, the coastline on the leeside of the sandbars advanced seaward by 35 m maximally while the rest adjacent coastline retreated severely by 44 m maximally within August 2017–July 2018. The model results demonstrate that the three sandbars have little effect on the tidal current but attenuate the incoming wave significantly. As a result, the medium-coarse sand of sandbars is transported onshore and the background silt is mainly transported offshore and partly in the longshore direction toward the northeast. The 2- and 5-year model simulation results further indicate that shoreline salient may form behind the sandbars and protrude offshore enough to reach the sandbars, similar to the tombolo behind the breakwater.

Wave and tidal power

2007 ◽  
Author(s):  
Dean L. Millar
Keyword(s):  
Wave Energy ◽  
Tidal Current ◽  
High Efficiency ◽  
Energy Resource ◽  
Energy Difference ◽  
Tidal Range ◽  
Tidal Power ◽  
Floating Structures ◽  
Wave Energy Converters ◽  
High Tidal Range

This chapter reviews how electricity can be generated from waves and tides. The UK is an excellent example, as the British Isles have rich wave and tidal resources. The technologies for converting wave power into electricity are easily categorized by location type. 1. Shoreline schemes. Shoreline Wave Energy Converters (WECs) are installed permanently on shorelines, from where the electricity is easily transmitted and may even meet local demands. They operate most continuously in locations with a low tidal range. A disadvantage is that less power is available compared to nearshore resources because energy is lost as waves reach the shore. 2. Nearshore schemes. Nearshore WECs are normally floating structures needing seafloor anchoring or inertial reaction points. The advantages over shoreline WECs are that the energy resource is much larger because nearshore WECs can access long-wavelength waves with greater swell, and the tidal range can be much larger. However, the electricity must be transmitted to the shore, thus raising costs. 3. Offshore schemes. Offshore WECs are typically floating structures that usually rely on inertial reaction points. Tidal range effects are insignificant and there is full access to the incident wave energy resource. However, electricity transmission is even more costly. Tidal power technologies fall into two fundamental categories:1. Barrage schemes. In locations with high tidal range a dam is constructed that creates a basin to impound large volumes of water. Water flows in and out of the basin on flood and ebb tides respectively, passing though high efficiency turbines or sluices or both. The power derives from the potential energy difference in water levels either side of the dam. 2. Tidal current turbines. Tidal current turbines (also known as free flow turbines) harness the kinetic energy of water flowing in rivers, estuaries, and oceans. The physical principles are analogous to wind turbines, allowing for the very different density, viscosity, compressibility, and chemistry of water compared to air. Waves are caused by winds, which in the open ocean are often of gale force (speed >14 m/s).

Impacts of human interventions on the evolution of the Ria Formosa barrier island system (S. Portugal)

Geomorphology ◽  
2019 ◽  
Vol 343 ◽  
pp. 129-144 ◽  
Author(s):  
Katerina Kombiadou ◽  
Ana Matias ◽  
Óscar Ferreira ◽  
A. Rita Carrasco ◽  
Susana Costas ◽  
...  
Keyword(s):  
Barrier Island ◽  
Ria Formosa ◽  
Human Interventions ◽  
Island System
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