Sedimentary processes and the evolution of the distal bayside of Long Point, Lake Erie

1994 ◽  
Vol 31 (9) ◽  
pp. 1461-1473 ◽  
Author(s):  
Robin G. D. Davidson-Arnott ◽  
Heather E. Conliffe Reid
Keyword(s):  
Lake Erie ◽  
Great Depth ◽  
Sediment Supply ◽  
Aerial Photographs ◽  
Lake Levels ◽  
Wave Refraction ◽  
The North ◽  
South Shore ◽  
High Lake Levels

Long Point spit, on the north shore of Lake Erie, is >40 km long and presently building into water that is >40 m deep. Annual sediment supply to the spit is estimated to be 1.0 × 106 m3∙a−1 and is derived from the erosion of cohesive bluffs along more than 90 km of shoreline to the west. The shoreline of the distal bayside consists of narrow barriers that connect the ends of dune ridges and enclose interdune ponds and swales. Unlike most barrier spits, the distal end shows little evidence of the formation of dune recurves, and the shoreline of the bayside, rather than fronting a protected bay, is exposed to waves generated by northeast winds blowing over a fetch >100 km. Results of wave refraction analysis indicate that because of the great depth of water at the tip, there is almost no refraction of the dominant westerly and southwesterly waves around the distal end, thus inhibiting the formation of recurves. Net sediment transport on the distal bayside is towards the distal end of the spit. The result is the development of a narrow spit platform extending the spit directly into the deepest part of Lake Erie. All sediment reaching the distal end along the exposed south shore is transported onto this platform and none reaches the distal bayside.The negative sediment budget on the distal bayside results in transgression of the shoreline through truncation of the dune ridges, and overwash and breaching of the small barriers. Historical aerial photographs show that most of the overwash and breaching occurs during periods of long-term high lake levels, with the barriers being rebuilt landward of their former position during the following periods of lower lake levels. Progradation of the south shore at the distal end is thus partly counterbalanced by the transgression of the bayside.

Toe erosion of glacial till bluffs: Lake Erie south shore

1995 ◽  
Vol 32 (7) ◽  
pp. 829-837 ◽  
Author(s):  
Shahalam M. N. Amin ◽  
Robin G. D. Davidson-Arnott
Keyword(s):  
Lake Erie ◽  
Multiple Regression Model ◽  
Lake Levels ◽  
Beach Sediment ◽  
Beach Width ◽  
The Face ◽  
Recession Rates ◽  
South Shore ◽  
High Lake Levels ◽  
Measurement Period

Toe erosion and rates of recession of the toe were measured at four sites along a 3.5 km long stretch of shoreline on the south shore of Lake Erie from April to December 1986. The shoreline consists of bluffs ranging from 5 to 12 m in height and developed in overconsolidated till. Toe erosion was measured at peg lines consisting of pins driven horizontally into the face of the bluff at 0.25 m intervals to a height of 1.75 m above the beach, and steel rods driven vertically into the beach with a spacing of 1.5 m. At each site three lines were established and monitored at 1–2 week intervals. Because of record high lake levels, beaches in front of the bluffs were generally <5 m wide, and some erosion was measured on all but three occasions. Recession of the toe during any measurement period was generally 2–6 cm, with the maximum recorded being about 12 cm. Wave action during high-magnitude storms resulted in erosion occurring much higher up the bluff face than for low-magnitude events, but the actual recession of the toe was not substantially greater. A multiple regression model shows that there is a significant relationship between toe recession and several variables that indirectly control wave energy at the bluff toe. However, factors such as beach width and thickness of beach sediment did not have a significant influence on recession rates in this study, likely because the high lake levels resulted in very narrow beaches at all four sites throughout the study period.

scholarly journals Mass mortality of Northern Map Turtles (Graptemys geographica)

2015 ◽  
Vol 129 (1) ◽  
pp. 80 ◽  
Author(s):  
Jordan Catrysse ◽  
Emily Slavik ◽  
Jonathan Choquette ◽  
Ashley E. Leifso ◽  
Christina M. Davy
Keyword(s):  
Lake Erie ◽  
Mass Mortality ◽  
Species At Risk ◽  
Long Term Effects ◽  
North Shore ◽  
The North ◽  
The Poor ◽  
Map Turtles ◽  
Graptemys Geographica

We report a mass mortality of Northern Map Turtles (Graptemys geographica [LeSueur, 1817]) on the north shore of Lake Erie, Ontario, Canada. Thirty-five dead adult females were recovered from a nesting area over a period of four weeks. Predation and boat strikes were both excluded as potential cause of death, but the actual cause could not be determined because of the poor condition of the carcasses. Other possible explanations for the mortality include poisoning, drowning, and infection with an unidentified pathogen. Mass mortality in long-lived species, such as turtles, can have long-term effects on population growth and is a cause for concern in a species at risk.

scholarly journals Holocene shoreline progradation and coastal evolution at Guichen and Rivoli Bays, southern Australia

The Holocene ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 106-124 ◽  
Author(s):  
Thomas SN Oliver ◽  
Colin V Murray-Wallace ◽  
Colin D Woodroffe
Keyword(s):  
Sea Level ◽  
South Australia ◽  
Narrow Channel ◽  
Sediment Supply ◽  
Osl Dating ◽  
Sea Levels ◽  
Wave Refraction ◽  
The North ◽  
Ground Penetrating ◽  
Shoreline Progradation

Prograded barrier systems record shoreline behaviour and palaeoenvironmental information. The Guichen Bay Holocene embayment fill succession in South Australia has been subject to several prominent studies; however, several important unanswered questions remained regarding the timing of the older ridge sets at this site. Additional Optically Stimulated Luminescence (OSL) dating indicates that progradation commenced in the southeastern corner of the plain ~7300 years ago and was rapid between ~5800 and ~5000 years ago. To augment this record, three OSL dating transects were constructed at nearby Rivoli Bay in the north, central and south. Rapid progradation occurred in the south and then north of the Rivoli plain until ~5000 years ago. Steady progradation occurred in the centre of the plain between ~5000 years ago and present. Rapid shoreline progradation at Guichen and Rivoli Bays before ~5000 years ago was due to the input of sediment from the erosion of Robe and Woakwine Ranges and the inner continental shelf as sea levels rose to present. Raised beach strata imaged with Ground Penetrating Radar (GPR) at Rivoli Bay suggest a sea-level highstand of +2 m above present ~3500 years ago, steadily falling and reaching the present ~1000 years ago. This concurs with evidence from Guichen Bay and may have promoted shoreline progradation. Sediment infilling of Guichen and Rivoli Bays and the fall in sea level restricted the marine corridor between the Woakwine and Robe Ranges to a narrow channel by ~4000 and ~2000 years in the north and south, respectively. Holocene shoreline behaviour was influenced by changing sediment supply and shoreline reorientation with changing wave refraction patterns.

scholarly journals LONG-TERM SHORELINE CHANGES ON MARGINAL COAST OF TIDAL FLAT IN TOKYO BAY AND RAPID DEFORMATION OF SAND BARS OWING TO TSUNAMI

2017 ◽  
pp. 1
Author(s):  
Yasumitsu Mikami
Keyword(s):  
Tidal Flat ◽  
River Mouth ◽  
Aerial Photographs ◽  
Tokyo Bay ◽  
Shoreline Changes ◽  
The North ◽  
Sand Bars ◽  
Sand Supply ◽  
Rapid Deformation

Long-term shoreline changes on the marginal coast of the Banzu tidal flat in Tokyo Bay were investigated using aerial photographs. In the area immediately north of the Obitsu River mouth, the beach was eroded owing to the decrease in sand supply from the river, resulting in the exposure of a layer composed of cohesive material in the previous tidal flat, and sand was transported northward to form a sand spit at the mouth of the north tributary. In 2011, the giant tsunami generated by the Great East Japan Earthquake propagated deep into Tokyo Bay, and sand bars were pushed landward by 7 m parallel to the shoreline owing to the tsunami overflow.

scholarly journals PROTOTYPE APPLICATIONS OF A GENERALIZED SHORELINE CHANGE NUMERICAL MODEL

1988 ◽  
Vol 1 (21) ◽  
pp. 94
Author(s):  
Hans Hanson Krueger ◽  
Mark B. Gravens ◽  
Nicholas C. Kraus
Keyword(s):  
Numerical Model ◽  
Lake Erie ◽  
Shoreline Change ◽  
Response Model ◽  
Shore Protection ◽  
The Third ◽  
The North ◽  
Design Alternatives ◽  
Wide Range

Three case studies are described in which long-term shoreline response was simulated using a numerical model. One project was along Kachemak Bay, Alaska and involved evaluation of design alternatives that included a detached breakwater, beach fill, and a revetment. The second project was on the north New Jersey coast and characterized by a long seawall and numerous groins. The third project was a model test of shoreline change behind three detached breakwaters Lake Erie. The shoreline response model used, called GENESIS, is demonstrated to have applicability to a wide range of commonly encountered shore protection situations.

scholarly journals A DETACHED BREAKWATER SYSTEM FOR BEACH PROTECTION

1980 ◽  
Vol 1 (17) ◽  
pp. 119
Author(s):  
James R. Walker ◽  
Denton Clark ◽  
Joan Pope
Keyword(s):  
Aerial Photography ◽  
Lake Erie ◽  
Summer Season ◽  
Shore Protection ◽  
Lake Levels ◽  
Design Procedures ◽  
Natural Processes ◽  
Adverse Impacts ◽  
Second Year ◽  
High Lake Levels

Three segmented, detached breakwaters were constructed In the fall of 1977 at Lakeview Park, Ohio, on Lake Erie, to protect a beachfill to be used for recreation and shore protection. This paper documents the design procedures which established the configuration of the breakwaters and the beachfill, and determined the need for a terminal groin. The beachfill has been monitored by aerial photography and bathymetric profiling. During the second year, a storm of near design intensity generated severe waves concurrently with high Lake levels and eroded the updrift beach; however, the initial beach configuration was partially restored by natural processes during the following summer season. The project has functioned well, with very little loss of sand from the system and without adverse impacts on the downdrift coast.

Conservation genetics of the wood turtle (Glyptemys insculpta) in Quebec, Canada

2005 ◽  
Vol 83 (6) ◽  
pp. 765-772 ◽  
Author(s):  
Nathalie Tessier ◽  
Sébastien Rioux Paquette ◽  
François-Joseph Lapointe
Keyword(s):  
Phylogenetic Analyses ◽  
Population Declines ◽  
Conservation Units ◽  
The North ◽  
Glyptemys Insculpta ◽  
South Shore ◽  
Two Populations ◽  
St Lawrence River ◽  
Wood Turtle

Throughout its range, the long-term persistence of the wood turtle (Glyptemys insculpta Le Conte, 1830) is jeopardized by habitat perturbations and commercial collection. The main objective of this study was to acquire knowledge on the genetic structure of wood turtle populations within Quebec, where the species reaches the northernmost limit of its range, to identify proper conservation units. The six known populations in Quebec were genetically characterized using five microsatellite loci. Genetic analyses revealed high variability among all populations (HO ranging from 0.561 to 0.886), suggesting that past population declines have not yet affected their genetic diversity. Since populations are located on both shores of the St. Lawrence River, two colonization hypotheses were tested to determine whether the River acted as a dispersal route or as a barrier. Results of AMOVA tests, phylogenetic analyses, and assignment tests demonstrated the clear distinction between populations from both shores, and three genetically different units were identified: the two populations on the north shore and a single homogenous group on the south shore.

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

Mafias on the Move

2011 ◽  
Author(s):  
Federico Varese
Keyword(s):  
United States ◽  
New York ◽  
Organized Crime ◽  
The United States ◽  
The West ◽  
Market Expansion ◽  
The North ◽  
Economic Transformations ◽  
At Will

Organized crime is spreading like a global virus as mobs take advantage of open borders to establish local franchises at will. That at least is the fear, inspired by stories of Russian mobsters in New York, Chinese triads in London, and Italian mafias throughout the West. As this book explains, the truth is more complicated. The author has spent years researching mafia groups in Italy, Russia, the United States, and China, and argues that mafiosi often find themselves abroad against their will, rather than through a strategic plan to colonize new territories. Once there, they do not always succeed in establishing themselves. The book spells out the conditions that lead to their long-term success, namely sudden market expansion that is neither exploited by local rivals nor blocked by authorities. Ultimately the inability of the state to govern economic transformations gives mafias their opportunity. In a series of matched comparisons, the book charts the attempts of the Calabrese 'Ndrangheta to move to the north of Italy, and shows how the Sicilian mafia expanded to early twentieth-century New York, but failed around the same time to find a niche in Argentina. The book explains why the Russian mafia failed to penetrate Rome but succeeded in Hungary. A pioneering chapter on China examines the challenges that triads from Taiwan and Hong Kong find in branching out to the mainland. This book is both a compelling read and a sober assessment of the risks posed by globalization and immigration for the spread of mafias.

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