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.

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.

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.

scholarly journals Glacial and lake fluctuations in the area of the west Kunlun mountains during the last 45 000 years

1992 ◽  
Vol 16 ◽  
pp. 79-84 ◽  
Author(s):  
Liu Chaohai ◽  
Li Shijie ◽  
Shi Yafeng
Keyword(s):  
Lacustrine Sediments ◽  
Southern Slope ◽  
Lake Levels ◽  
Humid Climate ◽  
The West ◽  
Kunlun Mountains ◽  
West Kunlun ◽  
High Lake Levels ◽  
The Last Glacial Maximum ◽  
The Last Glacial

There appear to have been several important glacial advances on the southern slope of the west Kunlun mountains, Tibetan Plateau, since 45 000 a BP. Based on the record of alternating till and lacustrine sediments and 14C determinations, these advances are dated to 23 000–16 000, 8500–8000, and 4000–2500 a BP, and to the 16th–19th century AD, with regional variations occurring during each of the advances. The glaciation of 23 000–16 000 a BP is equivalent to the last glacial maximum (LGM) and its scope and scale were much larger than any of the others. Lake changes are a response to both tectonic uplift of the plateau and global climatic change. With regard to the latter, both changes in precipitation and changes in the extent of glaciation can affect lake levels. High lake levels occurred during interstadial conditions between 40 000 and 30 000 a BP, when the area experienced a relatively warm and humid climate, and during the LGM, between 21 000 and 15 000 a BP. During the Holocene, lakes have been shrinking gradually, coincident with the dry climate of this period of time.

scholarly journals Glacial and lake fluctuations in the area of the west Kunlun mountains during the last 45 000 years

1992 ◽  
Vol 16 ◽  
pp. 79-84 ◽  
Author(s):  
Liu Chaohai ◽  
Li Shijie ◽  
Shi Yafeng
Keyword(s):  
Lacustrine Sediments ◽  
Southern Slope ◽  
Lake Levels ◽  
Humid Climate ◽  
The West ◽  
Kunlun Mountains ◽  
West Kunlun ◽  
High Lake Levels ◽  
The Last Glacial Maximum ◽  
The Last Glacial

There appear to have been several important glacial advances on the southern slope of the west Kunlun mountains, Tibetan Plateau, since 45 000 a BP. Based on the record of alternating till and lacustrine sediments and 14C determinations, these advances are dated to 23 000–16 000, 8500–8000, and 4000–2500 a BP, and to the 16th–19th century AD, with regional variations occurring during each of the advances. The glaciation of 23 000–16 000 a BP is equivalent to the last glacial maximum (LGM) and its scope and scale were much larger than any of the others.Lake changes are a response to both tectonic uplift of the plateau and global climatic change. With regard to the latter, both changes in precipitation and changes in the extent of glaciation can affect lake levels. High lake levels occurred during interstadial conditions between 40 000 and 30 000 a BP, when the area experienced a relatively warm and humid climate, and during the LGM, between 21 000 and 15 000 a BP. During the Holocene, lakes have been shrinking gradually, coincident with the dry climate of this period of time.

Global Maps of Lake-Level Fluctuations since 30,000 yr B.P.

1979 ◽  
Vol 12 (1) ◽  
pp. 83-118 ◽  
Author(s):  
F. Alayne Street ◽  
A. T. Grove
Keyword(s):  
Lake Level ◽  
Ice Sheets ◽  
Literature Survey ◽  
Sea Surface ◽  
Lake Levels ◽  
Lake Level Fluctuations ◽  
Average Abundance ◽  
The Tropics ◽  
High Lake Levels ◽  
Precipitation And Temperature

This paper presents selected world maps of lake-level fluctuations since 30,000 yr B.P. These are based on a literature survey of 141 lake basins with radiocarbon-dated chronologies. The resulting patterns are subcontinental in scale and show orderly variations in space and time. They reflect substantial changes in continental precipitation, evaporation, and runoff, which are due to glacial/interglacial fluctuations in the atmospheric and oceanic circulations. In the tropics, high lake levels are essentially an interglacial or interstadial phenomenon, although there are important exceptions. Since extensive lakes during the Holocene corresponded with relatively high sea-surface temperatures, and therefore presumably with high evaporation rates on land, they are interpreted as the result of higher precipitation. Tropical aridity culminated in most areas at, or just after, the glacial maximum, although the present day is also characterized by a below-average abundance of surface water. In extratropical regions the mapped patterns are more complex. They vary markedly with latitude and proximity to major ice sheets. In these areas, evidence is at present insufficient to evaluate the relative contributions of precipitation and temperature to the observed lake-level record.

Holocene Fluctuations of a Meromictic Lake in Southern British Columbia

1997 ◽  
Vol 48 (1) ◽  
pp. 100-113 ◽  
Author(s):  
David J. Lowe ◽  
John D. Green ◽  
Tom G. Northcote ◽  
Ken J. Hall
Keyword(s):  
Saline Lake ◽  
Basal Layer ◽  
Climatic Changes ◽  
Depositional Environments ◽  
Laminated Sediments ◽  
Lake Depth ◽  
Lake Levels ◽  
Short Term ◽  
Northwestern North America ◽  
High Lake Levels

Holocene deposits of Mahoney Lake, a meromictic saline lake located in a closed basin in the semi-arid Okanagan Valley, contain evidence of frequent and marked changes in lake depth (up to >12 m/10014C yr) probably caused by short-term changes in effective precipitation. We studied a 5.45-m-long core comprising a basal layer of inorganic mud overlain by a succession of layers of calcareous laminated and nonlaminated organic mud, marl, and sand. We used Mazama tephra to adjust nine radiocarbon ages for the hardwater effect. Meromixis developed ca. 900014C yr B.P., and the lake has been episodically meromictic for about half the time since. Because of close linkages between sediments and depositional environments in meromictic and saline lakes, we infer that laminated sediments indicate meromictic conditions and high lake levels (>ca. 12 m water depth), whereas thick marl layers and nonlaminated sediments indicate nonmeromictic conditions and thus low lake levels (<ca. 8 m depth). Many of the inferred short-term climatic changes have not been identified in previous studies in northwestern North America, perhaps because of insensitive climatic proxies, inadequate temporal resolution, or discounting of anomalous findings.

scholarly journals A PROLONGED SEASON OF OCCURRENCE FOR SCHISTOCERCA AMERICANA

1899 ◽  
Vol 31 (2) ◽  
pp. 28-28
Author(s):  
F. M. Webster
Keyword(s):  
Lake Erie ◽  
The State ◽  
Schistocerca Americana ◽  
The South ◽  
Northern Portion ◽  
South Shore

At Wooster, Ohio, this species was observed in the fieds on May 26, and at Alliance, nearly due east, on October 24, while at Bridgeport, in the extreme eastern central part of the State, it was found, active, on November 4, all during 1898. It appears to have been more numerous of late in the vicinity of the south shore of Lake Erie than elsewhere in the northern portion of the State, and more abundant than I have formerly observed it in the same latitude in Indiana and Illinois.

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