scholarly journals Seeking the Shore: Evidence for Active Submarine Canyon Head Incision Due to Coarse Sediment Supply and Focusing of Wave Energy

2018 ◽  
Vol 45 (22) ◽  
pp. 12,403-12,413 ◽  
Author(s):  
M. Elliot Smith ◽  
Samuel H. Werner ◽  
Daniel Buscombe ◽  
Noah J. Finnegan ◽  
Esther J. Sumner ◽  
...  
Keyword(s):  
Wave Energy ◽  
Submarine Canyon ◽  
Sediment Supply ◽  
Coarse Sediment

scholarly journals Wave Energy Assessment in the South Aquitaine Nearshore Zone from a 44-Year Hindcast

2020 ◽  
Vol 8 (3) ◽  
pp. 199 ◽  
Author(s):  
Ximun Lastiri ◽  
Stéphane Abadie ◽  
Philippe Maron ◽  
Matthias Delpey ◽  
Pedro Liria ◽  
...  
Keyword(s):  
Wave Energy ◽  
Unstructured Grid ◽  
Energy Resource ◽  
Wave Model ◽  
Submarine Canyon ◽  
Resource Assessment ◽  
Resource Information ◽  
Energy Assessment ◽  
Local Wave ◽  
The One

Wave resource assessment is the first step toward the installation of a wave energy converter (WEC). To support initiatives for wave energy development in the southwest of France, a coastal wave database is built from a 44-year hindcast simulation with the spectral wave model SWAN (Simulating WAve Nearshore) run on a high-resolution unstructured grid. The simulation includes shallow-water processes such as refraction, shoaling, and breaking. The model is validated against a five-year coastal wave buoy recording. The study shows that most of the resource is provided by sea states with wave heights ranging from 2 to 5 m, with wave periods from 10 and 15 s, and coming from a very narrow angular sector. The long hindcast duration and the refined unstructured grid used for the simulation allow assessment of the spatiotemporal distribution of wave energy across the coastal area. On the one hand, large longshore variations of the resource caused by steep bathymetric gradients such as the Capbreton submarine canyon are underlined. On the other hand, the study highlights that no specific long-term trend can be extracted regarding the coastal wave energy resource evolution. The provided downscaled local wave resource information may be used to optimize the location and design of a future WEC that could be deployed in the region.

scholarly journals Internal Tide Convergence and Mixing in a Submarine Canyon

2017 ◽  
Vol 47 (2) ◽  
pp. 303-322 ◽  
Author(s):  
Amy F. Waterhouse ◽  
Jennifer A. Mackinnon ◽  
Ruth C. Musgrave ◽  
Samuel M. Kelly ◽  
Andy Pickering ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Internal Wave ◽  
Wave Energy ◽  
Internal Tide ◽  
Submarine Canyon ◽  
Internal Tides ◽  
North Coast ◽  
Semidiurnal Tide ◽  
The North ◽  
Tidally Driven

AbstractObservations from Eel Canyon, located on the north coast of California, show that elevated turbulence in the full water column arises from the convergence of remotely generated internal wave energy. The incoming semidiurnal and bottom-trapped diurnal internal tides generate complex interference patterns. The semidiurnal internal tide sets up a partly standing wave within the canyon due to reflection at the canyon head, dissipating all of its energy within the canyon. Dissipation in the near bottom is associated with the diurnal trapped tide, while midwater isopycnal shear and strain is associated with the semidiurnal tide. Dissipation is elevated up to 600 m off the bottom, in contrast to observations over the flat continental shelf where dissipation occurs closer to the topography. Slope canyons are sinks for internal wave energy and may have important influences on the global distribution of tidally driven mixing.

scholarly journals Earthquakes drive large-scale submarine canyon development and sediment supply to deep-ocean basins

2018 ◽  
Vol 4 (3) ◽  
pp. eaar3748 ◽  
Author(s):  
Joshu J. Mountjoy ◽  
Jamie D. Howarth ◽  
Alan R. Orpin ◽  
Philip M. Barnes ◽  
David A. Bowden ◽  
...  
Keyword(s):  
Large Scale ◽  
Deep Ocean ◽  
Submarine Canyon ◽  
Sediment Supply

scholarly journals Detrital signals of coastal erosion and fluvial sediment supply during glacio-eustatic sea-level rise, Southern California, USA

Geology ◽  
2021 ◽  
Author(s):  
G.R. Sharman ◽  
J.A. Covault ◽  
D.F. Stockli ◽  
Z.T. Sickmann ◽  
M.A. Malkowski ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Detrital Zircon ◽  
Coastal Erosion ◽  
Southern California ◽  
Submarine Canyon ◽  
Sediment Supply ◽  
Sediment Budgets ◽  
The Face ◽  
Sea Fan

Coastal erosion, including sea-cliff retreat, represents both an important component of some sediment budgets and a significant threat to coastal communities in the face of rising sea level. Despite the importance of predicting future rates of coastal erosion, few prehistoric constraints exist on the relative importance of sediment supplied by coastal erosion versus rivers with respect to past sea-level change. We used detrital zircon U-Pb geochronology as a provenance tracer of river and deep-sea fan deposits from the Southern California Borderland (United States) to estimate relative sediment contributions from rivers and coastal erosion from late Pleistocene to present. Mixture modeling of submarine canyon and fan samples indicates that detrital zircon was dominantly (55%–86%) supplied from coastal erosion during latest Pleistocene (ca. 13 ka) sea-level rise, with lesser contributions from rivers, on the basis of unique U-Pb age modes relative to local Peninsular Ranges bedrock sources. However, sediment that was deposited when sea level was stable at its highest and lowest points since the Last Glacial Maximum was dominantly supplied by rivers, suggesting decreased coastal erosion during periods of sea-level stability. We find that relative sediment supply from coastal erosion is strongly dependent on climate state, corroborating predictions of enhanced coastal erosion during future sea-level rise.

Width control on event scale bedload dynamics in bedrock-confined channels

2021 ◽  
Author(s):  
Kristen Cook ◽  
Jens Turowski ◽  
Niels Hovius
Keyword(s):  
Random Sequence ◽  
Bedload Transport ◽  
Sediment Supply ◽  
Sediment Flux ◽  
Channel Width ◽  
Sediment Grain Size ◽  
Event Scale ◽  
Narrow Channels ◽  
Coarse Sediment ◽  
The Impact

<p>In mixed bedrock-alluvial rivers, the response of the system to a flood event can be affected by a number of factors, including coarse sediment availability in the channel, sediment supply from the hillslopes and upstream, flood sequencing, and coarse sediment grain size distribution. However, the impact of along-stream changes in channel width on bedload transport dynamics remains largely unexplored. We combine field data, theory, and numerical modeling to address this gap. Observations from two flood events in the Daan River gorge in western Taiwan suggest that coarse sediment evacuation and re-deposition can cause intra-flood changes of up to several meters in channel bed elevation that are distinct from measured before/after bed changes. We hypothesize that this could be related to the abrupt change in width between the 1 km long bedrock gorge and the river upstream and downstream. An analysis of the theoretical relationships between discharge, channel width, and bedload transport capacity shows that for a given slope, narrow channels transport bedload more efficiently than wide ones at low discharges, while wider channels are more efficient at high discharges. We used the model sedFlow to explore this effect, running a random sequence of floods through a channel with a narrow gorge section bounded upstream and downstream by wider reaches. Channel response to imposed floods is complex, as high and low discharges drive different spatial patterns of erosion and deposition, and the channel may experience both of these regimes during the peak and recession periods of each flood. Our modeling suggests that width differences alone can drive substantial variations in sediment flux and bed response, without the need for variations in sediment supply or mobility. Further, the deposition or erosion that takes place within a flood is often not reflected in the before/after changes to the bed, and this disconnect increases with increasing flood size.</p>

WAVE ENERGY, SEDIMENT SUPPLY, AND SEA-LEVEL FALL: LATE HOLOCENE BASIN INFILLING IN SOUTHERN BRAZIL

2015 ◽  
Author(s):  
CHRISTOPHER J. HEIN ◽  
IOANNIS Y. GEORGIOU ◽  
DUNCAN M. FITZGERALD ◽  
LUIS H.P. SOUZA ◽  
ANTONIO H.F. KLEIN ◽  
...  
Keyword(s):  
Sea Level ◽  
Wave Energy ◽  
Late Holocene ◽  
Sediment Supply ◽  
Southern Brazil ◽  
And Sea Level

scholarly journals The Potential Role of Artificial Marsh on Coastal Protection in Long Island Sound

2020 ◽  
Author(s):  
Amin Ilia
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Wave Energy ◽  
Salt Marshes ◽  
Hurricane Sandy ◽  
Sediment Supply ◽  
Coastal Protection ◽  
Climate Change Effects ◽  
Data Assessment ◽  
Accretion Rates

Connecticut marshes, like other marshes in the world, are vulnerable to anthropogenic and climate change effects. However, assessment of current sea level rise and average marsh accretion rates in Connecticut demonstrate sea level rise is not the main vulnerable factor for salt marshes loss. The study on the feasibility of developing an ecosystem-based on two coastlines in Connecticut, Guilford and Stratford, shows that both coastlines, like other coastlines in Connecticut, have limited wave energy, which is a positive factor for marsh growth. The available data assessment represents that sediment supply is the most important parameter to guarantee the resilience and sustainability of a newly developed salt marsh system in Connecticut. In Stratford, conditions for establishing a new ecosystem seem to be better, as the fetch length is pretty small, and there is some sediment supply for the ecosystem. In Guilford, wave energy is limited, but it is more than in Stratford case. Besides, sediment availability is low and the coastline experienced considerable erosion during hurricane Sandy and has not recovered yet.

scholarly journals SEDIMENT TRANSPORT PROCESSES AND COASTAL VARIABILITY ON THE ALASKAN NORTH SLOPE

1980 ◽  
Vol 1 (17) ◽  
pp. 81
Author(s):  
E.H. Owens ◽  
J.R. Harper ◽  
D. Nummedal
Keyword(s):  
Sediment Transport ◽  
Wave Energy ◽  
Energy Levels ◽  
Transport Processes ◽  
Sediment Supply ◽  
North Slope ◽  
Storm Events ◽  
Shore Zone ◽  
Ice Content ◽  
Alaskan North Slope

Shoreline development and shore-zone sediment transport on the Alaskan North Slope are dependent upon levels of wave energy, sea ice conditions, and the ice-sediment characteristics of eroding tundra cliffs. Considerable variation exists between the coastal processes and the shore-zone morphology of the Chukchi and Beaufort Sea beaches, (respectively west and east of Point Barrow). The supply of coarse sediments (sands or gravels) and the volumes of material eroded from tundra cliffs are a function of the initial character of the cliff sediments and of the ice content of the exposed cliffs. As cliff heights decrease, the ice content of the cliff increases, erosion rates increase but the sediment supply rates decrease. Wave-energy levels are relatively high and maintain a constant level on the Chukchi coast. The transport system on this coast is continuous and is augmented by storm events. On the Beaufort coast, energy levels are much lower, transport processes discontinuous, and storm events are therefore more significant. Sediments supplied to the coastal zone on the Chukchi coast are derived largely from the erosion of tundra cliffs and the barriers are continuous, linear, and stable. Rivers are the primary source of coastal sediments on the Beaufort coast and the more variable energy levels produce unstable barriers that are subject to aperiodic transport processes.

scholarly journals MECHANISM OF OFFSHORE SAND DISCHARGE INTO SUBMARINE CANYON TRIGGERED BY CONSTRUCTING DETACHED BREAKWATER CLOSE TO SHORELINE

2011 ◽  
Vol 1 (32) ◽  
pp. 18
Author(s):  
Koji Yamada ◽  
Takaaki Uda ◽  
Yoshio Suwa ◽  
Toshiro San-nami ◽  
Kou Furuike ◽  
...  
Keyword(s):  
Survey Data ◽  
Submarine Canyon ◽  
Sediment Supply ◽  
Beach Erosion ◽  
Aerial Photographs ◽  
Sand Transport ◽  
Submarine Canyons ◽  
Bathymetric Survey ◽  
Bed Slope

Several submarine canyons have developed offshore of the Aramata region of the Shimoni-ikawa coast in Toyama Bay, which is one of the three deep bays in Japan. The Kurobe River with a steep bed slope flows into the sea immediately north of this region, and a large amount of sediment has been supplied to this area, which has been transported by southward longshore sand transport. However, beach erosion has occurred owing to the decrease in sediment supply from the Kurobe River. Furthermore, since the construction of detached breakwaters as a measure against beach erosion, offshore sand transport has accelerated and beach erosion has become more severe. In this study, aerial photographs and bathymetric survey data were analyzed, then the mechanism of offshore sand transport was investigated using the BG model proposed by Serizawa et al. (2007).

Sign in / Sign up

Export Citation Format

Share Document