scholarly journals ARTIFICIAL BEACH UNITS ON LAKE MICHIGAN

1988 ◽  
Vol 1 (21) ◽  
pp. 211
Author(s):  
K.J. MacIntosh ◽  
C.D. Anglin

High water levels on Lake Michigan during 1985 and 1986 created substantial erosion of the shoreline and reduced the size and recreational potential of many of the parks and beaches. To prevent further erosion, protect existing properties and structures, and to create and improve recreational areas along the Lake Michigan shoreline, four coastal engineering projects were designed and constructed during this time. Artificial beach units stabilized by offshore breakwaters were used as the main component of each project. Physical hydraulic model studies were used to determine the orientation, size, and spacing of breakwaters and artificial beach units. Model predictions of beach profiles and plan shapes compare closely with prototype surveys. Surveys completed since construction demonstrate the stability of the beaches and support their use as effective, low maintenance shoreline protection. Prototype experience has shown that these projects are extremely successful both in their ability to withstand storms on the Great Lakes and to attract people for recreational activities.

1978 ◽  
Vol 1 (16) ◽  
pp. 58
Author(s):  
P.F. Hamblin

Storm surges in enclosed seas although generally not as large in amplitude as their oceanic counterparts are nonetheless of considerable importance when low lying shoreline profiles, shallow water depth, and favourable geographical orientation to storm winds occur together. High water may result in shoreline innundation and in enhanced shoreline erosion. Conversely low water levels are hazardous to navigation. The purpose of this paper is to discuss the problem of storm surge forecasting in enclosed basins with emphasis on automated operational procedures. In general, operational forecasting methods must be based on standard forecast parameters, require a minimum of computational effort in the preparation of the forecast, must be applicable to lakes of different geometry and to any point on the shore, and to be able to resolve water level changes on an hourly basis to 10 cm in the case of high water level excursions associated with large lakes and less than that for smaller lakes. Particular physical effects arising in lakes which make these constraints difficult to fulfill are the reflections of resurgences of water levels arising from lateral boundaries, the stability of the atmospheric boundary layer and the presence of such subsynoptic disturbances as squall lines and travelling pressure jumps.


2020 ◽  
Vol 10 (2) ◽  
pp. 44-52
Author(s):  
Sheeraz M. Ameen ◽  
Thamir M. Ahmed

The dam vertical lift gate is one of the most important operational parts that regulate the high head water flow to power plants as well as satisfying the water needs for projects and areas downstream of the dam. Due to the high water levels in the dam reservoir, the gates are subjected to many hydrostatic and dynamic pressures that affect their performance and stability. Hence, it became necessary to study all parameters that may cause excessive pressures which may lead to reduce the gate performance efficiency or even cause failure. In the current study, the pressure distribution along the bottom surface of various gate lip shapes has been measured and presented as contour maps using Surfer software. The pressure fluctuation was observed to indicate the intensity of flow separation and reattachment which, in turn, causes a vibration that may threaten the stability of the gate or impede its proper functioning. The pressures in this study are expressed as a dimensional coefficient through the integration of pressure measurements at 8 points distributed over the bottom gate surface. The high intensity of pressure attachment indicates the critical condition for hydraulic design.


1970 ◽  
Vol 1 (12) ◽  
pp. 53 ◽  
Author(s):  
James H. Saylor ◽  
Edward B. Hands

Longshore bars are permanent features of nearshore bathymetry along the windward coasts of the Great Lakes The stability and permanency of these features have been noted by numerous investigators, but movements of the bars and troughs vn relation to varying lake levels and incident wave energies are not fully understood Studies of nearshore bathymetry and sediment properties were conducted during 1967 and 1969 along a forty-five kilometer reach of the eastern coast of Lake Michigan Results show that the offshore bars migrate significantly due to changes in lake level, a rise of one-half meter in the surface of Lake Michigan between 1967 and 1969 was accompanied by a shoreward movement of bar crests and troughs over a distance averaging SO meters Elevations of the crests and troughs are also built upward toward new equiblibrium levels during rising water levels, but elevating of the crests lags the increase in stage Extensive shore erosion occurs because of the reduced effectiveness of longshore bars in dissipating incident wave energy The average crest depth was found to increase linearly in the offshore direction Average distances between crests increase exponentially These relationships are preserved during the bar growth and shifting that accompanies long term changes in lake level Bar troughs are characteristically crescent shaped, with no abrupt changes in slope Fathograms from several ranges show atypical trough configurations consisting of flat bottoms with discontinuities in slope on ascent to adoacent crests This unusual trough shape is indicative of an immobile stratum exposed along the bottom of the trough.


2020 ◽  
Author(s):  
Kevin A. Kincare ◽  
◽  
Monica Palaseanu-Lovejoy ◽  
Richard Becker ◽  
John A. Yellich

Shore & Beach ◽  
2021 ◽  
pp. 46-55
Author(s):  
Ethan Theuerkauf ◽  
C. Robin Mattheus ◽  
Katherine Braun ◽  
Jenny Bueno

Coastal storms are an important driver of geomorphic change along Great Lakes shorelines. While there is abundant anecdotal evidence for storm impacts in the region, only a handful of studies over the last few decades have quantified them and addressed system morphodynamics. Annual to seasonal lake-level fluctuations and declining winter-ice covers also influence coastal response to storms, yet relationships between hydrodynamics and geomorphology are poorly constrained. Given this, the Great Lakes region lags behind marine coasts in terms of predictive modeling of future coastal change, which is a necessary tool for proactive coastal management. To help close this gap, we conducted a year-long study at a sandy beach-dune system along the western shore of Lake Michigan, evaluating storm impacts under conditions of extremely high water level and absent shorefast ice. Drone-derived beach and dune topography data were used to link geomorphic changes to specific environmental conditions. High water levels throughout the year of study facilitated erosion during relatively minor wave events, enhancing the vulnerability of the system to a large storm in January 2020. This event occurred with no shorefast ice present and anomalously high winter water levels, resulting in widespread erosion and overwash. This resulted in 20% of the total accretion and 66% of the erosion documented at the site over the entire year. Our study highlights the importance of both antecedent and present conditions in determining Great Lakes shoreline vulnerability to storm impacts.


2007 ◽  
Vol 158 (1-2) ◽  
pp. 14-21
Author(s):  
Vasyl Sabadosh ◽  
Oleg Suprunenko

The upper Theresian Valley lies along the southwest-facing ridge of the Ukrainian Carpathians. Despite expansive forestation high water levels are frequent. The forest belongs to the state and is centrally administrated. Felling is sometimes outsourced to private companies and private companies have also been founded to process the timber. Job opportunities have become fewer and illegal work is increasing. A new democratic awareness has emerged since the «Orange Revolution» in 2004. With foreign investors, however, new risks emerge. The authors recommend giving monies from forest management to the communities, the founding of new wood processing enterprises and more transparent information.


The Holocene ◽  
2020 ◽  
pp. 095968362098168
Author(s):  
Christian Stolz ◽  
Magdalena Suchora ◽  
Irena A Pidek ◽  
Alexander Fülling

The specific aim of the study was to investigate how four adjacent geomorphological systems – a lake, a dune field, a small alluvial fan and a slope system – responded to the same impacts. Lake Tresssee is a shallow lake in the North of Germany (Schleswig-Holstein). During the Holocene, the lake’s water surface declined drastically, predominately as a consequence of human impact. The adjacent inland dune field shows several traces of former sand drift events. Using 30 new radiocarbon ages and the results of 16 OSL samples, this study aims to create a new timeline tracing the interaction between lake and dunes, as well, as how both the lake and the dunes reacted to environmental changes. The water level of the lake is presumed to have peaked during the period before the Younger Dryas (YD; start at 10.73 ka BC). After the Boreal period (OSL age 8050 ± 690 BC) the level must have undergone fluctuations triggered by climatic events and the first human influences. The last demonstrable high water level was during the Late Bronze Age (1003–844 cal. BC). The first to the 9th century AD saw slightly shrinking water levels, and more significant ones thereafter. In the 19th century, the lake area was artificially reduced to a minimum by the human population. In the dunes, a total of seven different phases of sand drift were demonstrated for the last 13,000 years. It is one of the most precisely dated inland-dune chronologies of Central Europe. The small alluvial fan took shape mainly between the 13th and 17th centuries AD. After 1700 cal. BC (Middle Bronze Age), and again during the sixth and seventh centuries AD, we find enhanced slope activity with the formation of Holocene colluvia.


1975 ◽  
Vol 2 (4) ◽  
pp. 381-391 ◽  
Author(s):  
J. W. Kamphuis

A number of lightweight coastal protection structures, built on the Lake Erie shore are discussed in this paper. There were two constraints on the design; limited funds and a very precarious downdrift beach. Thus the structures were inexpensive and the protection was low-key to prevent damage downdrift. In 1972–1974 these structures were subjected to a combination of large waves and high water levels and thus they were tested well beyond their design limits.The paper discusses the structures, their performance under normal conditions, and their performance during and after the abnormally high water levels. It is found that inexpensive, low-key structures are sufficiently strong to survive normal conditions, but fail by overtopping and flanking under conditions beyond their low design limits.


1999 ◽  
Vol 45 (150) ◽  
pp. 201-213 ◽  
Author(s):  
E.M. Shoemaker

AbstractThe effect of subglacial lakes upon ice-sheet topography and the velocity patterns of subglacial water-sheet floods is investigated. A subglacial lake in the combined Michigan–Green Bay basin, Great Lakes, North America, leads to: (1) an ice-sheet lobe in the lee of Lake Michigan; (2) a change in orientations of flood velocities across the site of a supraglacial trough aligned closely with Green Bay, in agreement with drumlin orientations; (3) low water velocities in the lee of Lake Michigan where drumlins are absent; and (4) drumlinization occurring in regions of predicted high water velocities. The extraordinary divergence of drumlin orientations near Lake Ontario is explained by the presence of subglacial lakes in the Ontario and Erie basins, along with ice-sheet displacements of up to 30 km in eastern Lake Ontario. The megagrooves on the islands in western Lake Erie are likely to be the product of the late stage of a water-sheet flood when outflow from eastern Lake Ontario was dammed by displaced ice and instead flowed westward along the Erie basin. The Finger Lakes of northern New York state, northeastern U.S.A., occur in a region of likely ice-sheet grounding where water sheets became channelized. Green Bay and Grand Traverse Bay are probably the products of erosion along paths of strongly convergent water-sheet flow.


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