The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform
Ping Wang - One of the best experts on this subject based on the ideXlab platform.
-
four year performance and associated controlling factors of several Beach nourishment projects along three Adjacent barrier islands west central florida usa
Coastal Engineering, 2012Co-Authors: Tiffany M Roberts, Ping WangAbstract:Abstract To quantify the performance of several Beach nourishment projects on three Adjacent barrier islands located in west-central Florida, a total of 5200 Beach and nearshore-profiles spaced at 300 m were surveyed monthly to bi-monthly from 2006 to 2010. Beach nourishment performance at annual temporal and kilometer spatial scales within the microtidal low-wave energy barrier island coast is most significantly influenced by the interruption of longshore sediment transport by complex tidal-inlet processes. The inlet processes directly influencing Adjacent Beach nourishment performance include longshore transport interruption resulting from divergence induced by wave refraction over an ebb-tidal shoal, flood-tidal currents along the Beach, and total littoral blockage by structured inlets. Secondary factors controlling the nourishment performance include project length and width, shoreline orientation, and antecedent geology. A morphologic indicator of a large longshore transport gradient within the study area is the absence of a nearshore sandbar. These non-barred Beaches are characterized by persistent shoreline erosion. The presence of a sandbar indicates the dominance of cross-shore processes, with bar migration in response to wave condition variations and a relatively stable shoreline. The entirety of a barrier island system should be considered when evaluating the performance of a nourishment.
-
comparison of the performance of three Adjacent and differently constructed Beach nourishment projects on the gulf peninsula of florida
Journal of Coastal Research, 2000Co-Authors: Richard A Davis, Ping Wang, Brad R SilvermanAbstract:Detailed Beach-profile monitoring was conducted at the three phases of Sand Key Beach nourishment on the Gulf Coast of Florida. The nourishment at Indian Rocks Beach, Indian Shores, and Redington Beach was monitored during six years, four years, and eight years respectively after nourishment. Quarterly or more frequent Beach and nearshore profile surveys were conducted in order to determine short-term (1 year) and long-term (4 to 8 years) rates of shoreline and Beach-nearshore volume changes. The overall performance of the Sand Key Beach nourishment is excellent. Redington Beach project has already exceeded the design lifetime of 7 years, and Indian Rocks Beach and Indian Shore projects are likely to exceed the design lifetime. The measured Beach-nearshore volume loss is small: 31% at Indian Rocks Beach over six years, 30% at Indian Shores over four years, and only 10% at Redington Beach during eight years. Performance of Beach nourishment is influenced by many factors. Those that are directly related to the three nourishment projects include: (1) relative location in the regional longshore sediment transport regime, (2) magnitude of wave energy, (3) sediment characteristics of the borrow material, (4) local reversal and/or gradient in longshore transport, (5) presence of hard structures, (6) Adjacent Beach nourishment, (7) variation of shoreline orientation, and (8) sand transfer and Beach-fill construction technique. The shoreline and Beach-nearshore volume change patterns at the three nourishment projects were different due to the different degrees of influence from the above factors, however, construction style is deemed to be an important contributor. The much less costly dragline and conveyor belt transfer technique used in the construction of Indian Shores project does not prove to be most cost effective for long-term performance.
Peter Squire - One of the best experts on this subject based on the ideXlab platform.
-
A mid-Holocene candidate tsunami deposit from the NW Cape (Western Australia)
Sedimentary Geology, 2016Co-Authors: Simon May, Max Engel, Simon Falvard, Maike Norpoth, Anna Pint, Dominik Brill, Anja Scheffers, Manuel Dierick, Raphael Paris, Peter SquireAbstract:Although extreme-wave events are frequent along the northwestern coast of Western Australia and tsunamis in 1994 and 2006 induced considerable coastal flooding locally, robust stratigraphical evidence of prehistoric tropical cyclones and tsunamis from this area is lacking. Based on the analyses of X-ray computed microtomography (μCT) of oriented sediment cores, multi-proxy sediment and microfaunal analyses, optically stimulated luminescence (OSL) and 14C-AMS dating, this study presents detailed investigations on an allochthonous sand layer of marine origin found in a back-barrier depression on the NW Cape Range peninsula. The event layer consists of material from the Adjacent Beach and dune, fines and thins inland, and was traced up to ~ 400 m onshore. Although a cyclone-induced origin cannot entirely be ruled out, the particular architecture and fabric of the sediment, rip-up clasts and three subunits point to deposition by a tsunami. As such, it represents the first stratigraphical evidence of a prehistoric, mid-Holocene tsunami in NW Western Australia. It was OSL-dated to 5400–4300 years ago, thus postdating the regional mid-Holocene sea-level highstand.
Kock, Alison A - One of the best experts on this subject based on the ideXlab platform.
-
Summer at the Beach: spatio-temporal patterns of white shark occurrence along the inshore areas of False Bay, South Africa
'Springer Science and Business Media LLC', 2018Co-Authors: Kock, Alison A, Photopoulou Theoni, Durbach Ian, Mauff Katya, Meÿer Michael, Kotze Deon, Griffiths, Charles L, O’riain M JustinAbstract:Background Understanding white shark (Carcharodon carcharias) habitat use in coastal areas Adjacent to large cities, is an important step when formulating potential solutions to the conservation conflict that exists between humans and large predatory sharks. In this study, we present the findings of a 2.5-year study of white shark occurrence and movement patterns Adjacent to the City of Cape Town in False Bay, South Africa, with a focus on spring and summer months. Fifty-one white sharks were monitored annually at three offshore and twelve inshore sites by VR2 acoustic receivers, over 975 days from 1 May 2005 to 31 December 2007. Results Occurrence patterns at inshore sites during spring and summer were analysed using a generalized additive mixed model (GAMM) with a spatial term (longitude, latitude), time of day and year included as explanatory variables for site use. We found that sharks occurred more frequently at inshore sites along the northern and northwestern shores, compared to the rest of the bay, and they transitioned most frequently between four Adjacent Beach sites that encompass the most popular recreational water use areas in Cape Town. There was significant diel variation, with higher shark occurrence around midday, and a peak in shark occurrence in 2005, when human-shark interactions also peaked. However, we found no effect of shark size on occurrence patterns at inshore sites. Conclusions White sharks showed the highest levels of occurrence at specific inshore sites between Muizenberg and Strandfontein Beach, and thus inclusion of these sites within False Bay’s marine protected area (MPA) network or recognition as Ecological or Biological Significant Areas (EBSAs) should be a future consideration. These insights into white shark habitat use at inshore sites in False Bay are important for successfully applying the principles of marine spatial planning (MSP) and for making science-based policy decisions. Furthermore, this information can be used to reduce potential shark-human conflict by incorporating it into future shark safety education campaigns
-
Summer at the Beach : spatio-temporal patterns of white shark occurrence along the inshore areas of False Bay, South Africa
'Springer Science and Business Media LLC', 2018Co-Authors: Kock, Alison A, Photopoulou Theoni, Durbach Ian, Mauff Katya, Meÿer Michael, Kotze Deon, Griffiths Charles, O'riain M. JustinAbstract:Bursary funding for AAK was provided for her MSc research from the National Research Foundation and for her PhD research through a grant to CG from the National Research Foundation (South Africa) (www.nrf.ac.za) SEAChange Programme. The Department of Environmental Affairs provided additional research equipment and ship time. The Save Our Seas Foundation provided a grant to AAK to conduct this research.Background: Understanding white shark (Carcharodon carcharias) habitat use in coastal areas Adjacent to large cities, is an important step when formulating potential solutions to the conservation conflict that exists between humans and large predatory sharks. In this study, we present the findings of a 2.5-year study of white shark occurrence and movement patterns Adjacent to the City of Cape Town in False Bay, South Africa, with a focus on spring and summer months. Fifty-one white sharks were monitored annually at three offshore and twelve inshore sites by VR2 acoustic receivers, over 975 days from 1 May 2005 to 31 December 2007. Results: Occurrence patterns at inshore sites during spring and summer were analysed using a generalized additive mixed model (GAMM) with a spatial term (longitude, latitude), time of day and year included as explanatory variables for site use. We found that sharks occurred more frequently at inshore sites along the northern and northwestern shores, compared to the rest of the bay, and they transitioned most frequently between four Adjacent Beach sites that encompass the most popular recreational water use areas in Cape Town. There was significant diel variation, with higher shark occurrence around midday, and a peak in shark occurrence in 2005, when human-shark interactions also peaked. However, we found no effect of shark size on occurrence patterns at inshore sites. Conclusions: White sharks showed the highest levels of occurrence at specific inshore sites between Muizenberg and Strandfontein Beach, and thus inclusion of these sites within False Bay’s marine protected area (MPA) network or recognition as Ecological or Biological Significant Areas (EBSAs) should be a future consideration. These insights into white shark habitat use at inshore sites in False Bay are important for successfully applying the principles of marine spatial planning (MSP) and for making science-based policy decisions. Furthermore, this information can be used to reduce potential shark-human conflict by incorporating it into future shark safety education campaigns.Publisher PDFPeer reviewe
Irene Delgadofernandez - One of the best experts on this subject based on the ideXlab platform.
-
investigation of three dimensional wind flow behaviour over coastal dune morphology under offshore winds using computational fluid dynamics cfd and ultrasonic anemometry
Earth Surface Processes and Landforms, 2011Co-Authors: Derek Jackson, J H M Beyers, Kevin Lynch, J A G Cooper, Andreas Baas, Irene DelgadofernandezAbstract:The behaviour of offshore‐directed winds over coastal dune and Beach morphology was examined using a combination of modelling (3‐D computational fluid dynamics (CFD)) and field measurement. Both model simulations and field measurements showed reversal of offshore flows at the back Beach and creation of an onshore sediment transport potential. The influence of flow reversals on the Beach‐dune transport system and foredune growth patterns has previously received little attention. Detailed wind flow measurements were made using an extensive array of mast‐mounted, 3‐D ultrasonic anemometers (50 Hz), arranged parallel to the dominant incident wind direction. Large eddy simulation (LES) of the offshore wind flow over the dune was conducted using the open‐source CFD tool openFOAM. The computational domain included a terrain model obtained by airborne LiDAR and detailed ground DGPS measurements. The computational grid (~22 million cells) included localized mesh refinement near the complex foredune terrain to capture finer details of the dune morphology that might affect wind flows on the Adjacent Beach. Measured and simulated wind flow are presented and discussed. The CFD simulations offer new insights into the flow mechanics associated with offshore winds and how the terrain steering of wind flow impacts on the geomorphological behaviour of the dune system. Simulation of 3‐D wind flows over complex terrain such as dune systems, presents a valuable new tool for geomorphological research, as it enables new insights into the relationship between the wind field and the underlying topography. The results show that offshore and obliquely offshore winds result in flow reversal and onshore directed winds at distances of up to 20m from the embryo dune toe. The potential geomorphological significance of the findings are discussed and simple calculations show that incoming offshore and obliquely offshore winds with mean velocities over 13m s−1 and 7m s−1, respectively, have the potential to create onshore‐directed winds at the back Beach with mean velocities above 3.3m s−1. These are above the threshold of movement for dry sand and support previous conclusions about the significance of offshore winds in dune and Beach budget calculations.
Simon May - One of the best experts on this subject based on the ideXlab platform.
-
A mid-Holocene candidate tsunami deposit from the NW Cape (Western Australia)
Sedimentary Geology, 2016Co-Authors: Simon May, Max Engel, Simon Falvard, Maike Norpoth, Anna Pint, Dominik Brill, Anja Scheffers, Manuel Dierick, Raphael Paris, Peter SquireAbstract:Although extreme-wave events are frequent along the northwestern coast of Western Australia and tsunamis in 1994 and 2006 induced considerable coastal flooding locally, robust stratigraphical evidence of prehistoric tropical cyclones and tsunamis from this area is lacking. Based on the analyses of X-ray computed microtomography (μCT) of oriented sediment cores, multi-proxy sediment and microfaunal analyses, optically stimulated luminescence (OSL) and 14C-AMS dating, this study presents detailed investigations on an allochthonous sand layer of marine origin found in a back-barrier depression on the NW Cape Range peninsula. The event layer consists of material from the Adjacent Beach and dune, fines and thins inland, and was traced up to ~ 400 m onshore. Although a cyclone-induced origin cannot entirely be ruled out, the particular architecture and fabric of the sediment, rip-up clasts and three subunits point to deposition by a tsunami. As such, it represents the first stratigraphical evidence of a prehistoric, mid-Holocene tsunami in NW Western Australia. It was OSL-dated to 5400–4300 years ago, thus postdating the regional mid-Holocene sea-level highstand.