How long are tidal channels?

2009 ◽  
Vol 643 ◽  
pp. 479-494 ◽  
Author(s):  
G. SEMINARA ◽  
S. LANZONI ◽  
N. TAMBRONI ◽  
M. TOFFOLON
Keyword(s):  
Coastal Wetlands ◽  
Characteristic Length ◽  
Flow Speed ◽  
Tidal Flats ◽  
Field Observations ◽  
Sediment Characteristics ◽  
Tidal Channels ◽  
Analytical Treatment ◽  
Equilibrium Length ◽  
Inlet Conditions

Do tidal channels have a characteristic length? Given the sediment characteristics, the inlet conditions and the degree of channel convergence, can we predict it? And how is this length affected by the presence of tidal flats adjacent to the channel? We answer the above questions on the basis of a fully analytical treatment, appropriate for the short channels typically observed in coastal wetlands. The equilibrium length of non-convergent tidal channels is found to be proportional to the critical flow speed for channel erosion. Channel convergence causes concavity of the bed profile. Tidal flats shorten equilibrium channels significantly. Laboratory and field observations substantiate our findings.

scholarly journals Continuous Change Mapping to Understand Wetland Quantity and Quality Evolution and Driving Forces: A Case Study in the Liao River Estuary from 1986 to 2018

2021 ◽  
Vol 13 (23) ◽  
pp. 4900
Author(s):  
Jianwei Peng ◽  
Shuguang Liu ◽  
Weizhi Lu ◽  
Maochou Liu ◽  
Shuailong Feng ◽  
...  
Keyword(s):  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Driving Forces ◽  
Land Reclamation ◽  
River Estuary ◽  
Tidal Flats ◽  
Liaoning Province ◽  
Coastal Zones ◽  
Continuous Change ◽  
Landsat Images

Coastal wetland ecosystems, one of the most important ecosystems in the world, play an important role in regulating climate, sequestering blue carbon, and maintaining sustainable development of coastal zones. Wetland landscapes are notoriously difficult to map with satellite data, particularly in highly complex, dynamic coastal regions. The Liao River Estuary (LRE) wetland in Liaoning Province, China, has attracted major attention due to its status as Asia’s largest coastal wetland, with extensive Phragmites australis (reeds), Suaeda heteroptera (seepweed, red beach), and other natural resources that have been continuously encroached upon by anthropogenic land-use activities. Using the Continuous Change Detection and Classification (CCDC) algorithm and all available Landsat images, we mapped the spatial–temporal changes of LRE coastal wetlands (e.g., seepweed, reed, tidal flats, and shallow marine water) annually from 1986 to 2018 and analyzed the changes and driving forces. Results showed that the total area of coastal wetlands in the LRE shrank by 14.8% during the study period. The tidal flats were the most seriously affected type, with 45.7% of its total area lost. One of the main characteristics of wetland change was the concurrent disappearance and emergence of wetlands in different parts of the LRE, creating drastically different mixtures of wetland quality (e.g., wetland age composition) in addition to area change. The reduction and replacement/translocation of coastal wetlands were mainly caused by human activities related to urbanization, tourism, land reclamation, and expansion of aquaculture ponds. Our efforts in mapping annual changes of wetlands provide direct, specific, and spatially explicit information on rates, patterns, and causes of coastal wetland change, both in coverage and quality, so as to contribute to the effective plans and policies for coastal management, preservation, and restoration of coastal ecosystem services.

Tidal Flats and Associated Tidal Channels

1982 ◽  
Author(s):  
Robert J. Weimer ◽  
James D. Howard ◽  
Donald R. Lindsay
Keyword(s):  
Tidal Flats ◽  
Tidal Channels

scholarly journals STABILITY CRITERIA FOR TIDAL BASINS

1974 ◽  
Vol 1 (14) ◽  
pp. 93 ◽  
Author(s):  
Eberhard Renger ◽  
Hans-Werner Partenscky
Keyword(s):  
Industrial Area ◽  
Offshore Structures ◽  
Tidal Flats ◽  
Relative Volume ◽  
Drainage Area ◽  
Tidal Basin ◽  
Tidal Channels ◽  
The North ◽  
Contour Level ◽  
The Stability

The contribution deals with the morphologic examinations and calculations for a deep-water harbour which is to be constructed in the tidal flats of the Elbe estuary near the North Sea islands of Scharhorn and Neuwerk. An attempt is made to examine the stability of tidal channels (gullies)and tidal flats which may be disturbed to a greater or lesser extent by the various proposals for the connecting dike between the industrial area near the harbour and the coastline. The underlying logic for the determination of the equilibrium of the flats and the quantitative solution for the sand-balance is as follows: It has been shown in several empirical investigations that the increase of the relative volume of the tidal basin (V/VM ), referenced to the gully volume for MLW, can be determined as a simple function to the base (a)logarithm of the geodetic elevation (z*) between MLW and any higher contour level up to MHW. Furthermore it can be shown that (VMT ) is also a function of the tidal drainage area (E). The base(a)has been related to the size of the tidal drainage area (E), because this area is subject to considerable modification by offshore structures such as dikes and causeways.

scholarly journals Biota from the coastal wetlands of Praia da Vitória (Terceira, Azores, Portugal): Part 4 – Vascular plants

2019 ◽  
Vol 7 ◽  
Author(s):  
Rui Elias ◽  
Mariana Brito ◽  
César Pimentel ◽  
Elisabete Nogueira ◽  
Paulo Borges
Keyword(s):  
Species Composition ◽  
Rare Species ◽  
Coastal Wetlands ◽  
Vascular Plants ◽  
New Records ◽  
Vascular Plant ◽  
Field Observations ◽  
Yearly Variation ◽  
Plant Richness ◽  
Juncus Maritimus

The data presented here come from field observations, carried out between 2014 and 2017, as part of a LIFE research project aiming to preserve and restore three coastal wetlands of Praia da Vitória (Terceira Island, Azores, Portugal) (LIFE-CWR). A total of 23 vascular plant species surveys were carried out in three sites: one for each semester in Paul da Praia da Vitória (PPV) and Paul da Pedreira do Cabo da Praia (PPCP); one for each semester (except in 2014) in Paul do Belo Jardim (PBJ). The main objectives were to determine the plant richness of the three sites and to monitor yearly variation on species composition. A total of 107 taxa, belonging to 50 families, were observed, many of which are new records for the area, especially in PBJ and PPCP, where 78 and 92% of species records were new. A few very rare species in the Azores were recorded in these coastal wetlands, namely Lotus creticus, Bolboschoenus maritimus, Juncus maritimus and Polygonum maritimum.

Updating global coastal wetland areas presented in Davidson and Finlayson (2018)

2019 ◽  
Vol 70 (8) ◽  
pp. 1195 ◽  
Author(s):  
Nick C. Davidson ◽  
C. Max Finlayson
Keyword(s):  
Salt Marshes ◽  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Tidal Flats ◽  
Seagrass Beds ◽  
Wetland Area

Global and regional areas and trends in area of unvegetated tidal flats, salt marshes, mangroves and seagrass beds are updated and corrected from those published in Davidson and Finlayson (2018). The global area of coastal wetlands is now estimated as a minimum of 1.42×106 km2, ~8.9–9.5% of an updated global wetland area of 15.0×106–16.0×106 km2.

scholarly journals Facies architecture of heterolithic tidal deposits: the Holocene Holland Tidal Basin

2007 ◽  
Vol 86 (4) ◽  
pp. 389-402 ◽  
Author(s):  
M.E. Donselaar ◽  
C.R. Geel
Keyword(s):  
Tidal Flats ◽  
Spatial Position ◽  
Tidal Basin ◽  
Tidal Channels ◽  
Facies Architecture ◽  
The Holocene ◽  
Architecture Model ◽  
High Data ◽  
Cone Penetration Tests ◽  
Estuarine Reservoir

AbstractThe size, shape and spatial position of lithofacies types (or facies architecture) in a tidal estuarine basin are complex and therefore difficult to model. The tidal currents in the basin concentrate sand-sized sediment in a branching pattern of tidal channels and fringing tidal flats. Away from the sandy tidal flats the sediment gradually changes to mud-dominated heterolithic deposits and clay. In this paper the facies analysis of a tidal estuarine basin, the Holocene Holland Tidal Basin (HHTB) is presented based on core data and Cone Penetration Tests (CPT). Four lithofacies associations are recognized: (1) tidal channel sand, (2) sand-dominated heterolithic inter-tidal flat, (3) mud-dominated heterolithic inter-channel and (4) fresh-water peat. The high data density allowed for the construction of a detailed facies architecture model in which the size, shape and spatial position of the tidal estuarine facies elements were established. The results can be used to improve the reservoir modelling in highly heterogeneous estuarine reservoir settings.

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