Performance of Light Coastal Structures Under Normal and High Water Conditions

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.

1986 ◽  
Vol 21 (3) ◽  
pp. 411-421 ◽  
Author(s):  
Efraim Halfon

Abstract Perchloroethylene (PERC) is a heavier-than-water, soluble and volatile solvent used primarily in the dry cleaning business. Black puddles (popularly known the the “blob”), containing several contaminants inducing PERC, were reported in the St. Clair River bottom sediments downstream from Sarnia in 1984 and in 1985. The TOXFATE model is used to predict the fate of PERC and the relative importance of volatilization in relation to water transport. Simulations show that in the St. Clair-Detroit River system about 82% (78-87%). under a variety of temperature and wind conditions) of the PERC loading is volatilized, about 17% (12-21%) of loading enters Lake Erie (more in winter, less in summer) and only about 1% remains in the system. The residence half life of PERC being transported in the water from Sarnia to Lake Erie is 350-400 hours and the half life of PERC being volatilized is 80-85 hours. A sensitivity analysis shows the importance of knowing the daily loadings to compute, in real time, local water concentrations following a PERC spill. The high water levels in the St. Clair River system do not influence the fate of PERC. Given the high volatility of PERC low temperatures and wind speeds do not reduce significantly the rate of removal of PERC from the system through volatilize nation.


Respati ◽  
2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Andika Agus Slameto ◽  
Eko Pramono ◽  
Zainal Arifin

INTISARIBanjir adalah bencana alam yang sulit di deteksi kapan akan datang terutama di musim hujan. Meskipun sudah dilakukan upaya dengan melakukan analisis terhadap data curah hujan serta tinggi permukaan air setiap periodenya, namun upaya tersebut dirasa masih belum dapat menyelesaikan permasalahan yang ada. Selain dari sisi manusia nya sendiri, solusi dari sisi teknologi juga diharapkan dapat penyelesaian permasalahan ini. Teknologi untuk deteksi dini bencana banjir akan dibutuhkan sebagai alternatif untuk membantu menyelesaikan permasalahan serta membantu dalam proses pengambilan keputusan guna meningkatkan kinerja instansi yang bekerja untuk memantau volume air sungai sehingga memperoleh kondisi air yang lebih cepat dan akurat. Tinggi permukaan air tentu menjadi salah satu faktor yang menyebabkan potensi banjir dimana permukaan air dapat diukur. DTMF merupakan metode pensinyalan yang nantinya akan dipadukan dengan sensor yang dapat digunakan untuk mengukur ketinggian permukaan air yang hasilnya nanti akan dikirim melalui gelombang radio. Dengan pengiriman sinyal melalui gelombang radio ini maka akan lebih efektif karena tidak memerlukan biaya seperti halnya melalui sms dan IoT.Kata kunci— DTMF, Arduino, Pendeteksi Banjir, SWOT, Gelombang Radio ABSTRACTFloods are natural disasters that are difficult in the detection of when it will come mainly in the rainy season. Despite efforts by conducting an analysis of the data of rainfall and high water levels at each, but those efforts proved still unable to resolve the existing problems. Aside from the human side of his own, the solution from the tech side is also expected to be the resolution of this issue. Technology for early detection of catastrophic flooding will be required as an alternative to help solve problems as well as help in the decision-making process in order to improve the performance of agencies who work to monitor the volume of river water so obtain water conditions more quickly and accurately. High water levels would certainly be one of the factors that lead to potential flooding where water levels can be measured. DTMF signalling is a method which will be combined with sensors that can be used to measure the height of the surface of the water which results will be sent via radio waves. With the delivery of the signal via radio waves it then it will be more effective because it doesn't cost as much as through sms and IoT.Keyword — DTMF, Arduino, Flood Detection, SWOT, Radio Wave


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.


1971 ◽  
Vol 61 (3) ◽  
pp. 579-590 ◽  
Author(s):  
William Enkeboll

abstract Soil and water conditions had an effect on the degree of damage to structures. Most structures were located on alluvium with a high water table. Settlements occurred in dike and causeway fill in Chimbote harbor. Severe problems to communication occurred in some areas through embankment failures and road slides.


2018 ◽  
Vol 18 (4) ◽  
pp. 1247-1260 ◽  
Author(s):  
Gemma L. Franklin ◽  
Alec Torres-Freyermuth ◽  
Gabriela Medellin ◽  
María Eugenia Allende-Arandia ◽  
Christian M. Appendini

Abstract. Reefs and sand dunes are critical morphological features providing natural coastal protection. Reefs dissipate around 90 % of the incident wave energy through wave breaking, whereas sand dunes provide the final natural barrier against coastal flooding. The storm impact on coastal areas with these features depends on the relative elevation of the extreme water levels with respect to the sand dune morphology. However, despite the importance of barrier reefs and dunes in coastal protection, poor management practices have degraded these ecosystems, increasing their vulnerability to coastal flooding. The present study aims to theoretically investigate the role of the reef–dune system in coastal protection under current climatic conditions at Puerto Morelos, located in the Mexican Caribbean Sea, using a widely validated nonlinear non-hydrostatic numerical model (SWASH). Wave hindcast information, tidal level, and a measured beach profile of the reef–dune system in Puerto Morelos are employed to estimate extreme runup and the storm impact scale for current and theoretical scenarios. The numerical results show the importance of including the storm surge when predicting extreme water levels and also show that ecosystem degradation has important implications for coastal protection against storms with return periods of less than 10 years. The latter highlights the importance of conservation of the system as a mitigation measure to decrease coastal vulnerability and infrastructure losses in coastal areas in the short to medium term. Furthermore, the results are used to evaluate the applicability of runup parameterisations for beaches to reef environments. Numerical analysis of runup dynamics suggests that runup parameterisations for reef environments can be improved by including the fore reef slope. Therefore, future research to develop runup parameterisations incorporating reef geometry features (e.g. reef crest elevation, reef lagoon width, fore reef slope) is warranted.


Author(s):  
A.-L. Montreuil ◽  
M. Chen ◽  
A. Esquerré ◽  
R. Houthuys ◽  
R. Moelans ◽  
...  

<p><strong>Abstract.</strong> Sustainable management of the coastal resources requires a better understanding of the processes that drive coastline change. The coastline is a highly dynamic sea-terrestrial interface. It is affected by forcing factors such as water levels, waves, winds, and the highest and most severe changes occur during storm surges. Extreme storms are drivers responsible for rapid and sometimes dramatic changes of the coastline. The consequences of the impacts from these events entail a broad range of social, economic and natural resource considerations from threats to humans, infrastructure and habitats. This study investigates the impact of a severe storm on coastline response on a sandy multi-barred beach at the Belgian coast. Airborne LiDAR surveys acquired pre- and post-storm covering an area larger than 1 km<sup>2</sup> were analyzed and reproducible monitoring solutions adapted to assess beach morphological changes were applied. Results indicated that the coast retreated by a maximum of 14.7 m where the embryo dunes in front of the fixed dunes were vanished and the foredune undercut. Storm surge and wave attacks were probably the most energetic there. However, the response of the coastline proxies associated with the mean high water line (MHW) and dunetoe (DuneT) was spatially variable. Based on the extracted beach features, good correlations (r>0.73) were found between coastline, berm and inner intertidal bar morphology, while it was weak with the most seaward bars covered in the surveys. This highlights the role of the upper features on the beach to protect the coastline from storm erosion by reducing wave energy. The findings are of critical importance in improving our knowledge and forecasting of coastline response to storms, and also in its translation into management practices.</p>


2021 ◽  
Vol 869 (1) ◽  
pp. 012030
Author(s):  
W B Setyawan ◽  
E Wulandari

Abstract Meulaboh is coastal city that has tourism potential. The city has been facing coastal erosion hazard since a long time from high energy wave activity coming from Indian Ocean. To protect the coast from the erosion hazard, a coastal defence structures were built along the city’s coast overlooking the Indian Ocean. Before the 2004 tsunami, hard structures built on the coast that open to waves from the Indian Ocean were damaged by daily wave activity. This study assess effectiveness of the current coastal protection structures protect coastline in the three coastal segments of the city, namely the Padang Seurahet, Ujung Karang and Kampung Pasir, in order to find out if the construction of the structures is the right choice. Related to the tourism potential of Meulaboh City also studied the possibility to expand the function of the structures. The coastal protection structures data for this study were mainly obtained from field observations in June 2021. Effectiveness of the structures protecting coastline were analysed based on technical criteria. Meanwhile, possibility to expand the function of the structures were analysed according to environmental condition of the coastal segments and types of tourism activity. The results of this study show that the hard structure that now exists on Meulaboh coast can protect the city’s coast from the hazard of erosion without negatively impacting the surrounding coastline. In addition, the structure is considered to be expandable to support the development of tourism potential of Meulaboh City. Thus it can be conclude that the choice of hard structure for coastal protection in most of Meulaboh coastline is appropriate.


2020 ◽  
Vol 9 (10) ◽  
pp. e4479108555
Author(s):  
Josué Ribeiro da Silva Nunes ◽  
Carolina Joana da Silva ◽  
Solange Kimie Ikeda-Castrillon ◽  
Nilo Leal Sander

The Pantanal wetland Mato Grosso, Brazil is among the largest floodplains in the world, with a mosaic of different habitats and rich aquatic and terrestrial biota. The habitat mosaics are found in the Chacororé and Sinhá Mariana lake System. These parental lakes of the Cuiabá River, a left tributary of the Upper Paraguay River, are known for their aquatic productivity and scenic beauty. The characteristics of these lakes and their floodplains are showed through the difference between their waters, the diversity of the aquatic macrophytes communities, fish communities and aquatic birds. Our study looked at changes in limnological variables as well as diversity of aquatic birds, during high water or flooded phase; medium water or receding phase; and the low water or dry phase. We used a temporary small lagoon in the floodplain of this system as our study area. The flood pulse is the main ecological factor affecting the Pantanal; it modifies ecological process and species composition. The water depth decreases during the season, decreasing electrical conductivity, dissolved phosphate and nitrate, water transparency, dissolved oxygen and biomass of aquatic macrophyte; and increasing calcium, total phosphorus and total nitrogen. We also observed increase in species richness and abundance of aquatic birds during the receding phase. Results show that the number of species (density) of aquatic birds increased from 10 to 30 species and the numbers of individuals from 40 to 936. The maximum richness and abundance of aquatic birds was registered during the receding phase.


1986 ◽  
Vol 32 (110) ◽  
pp. 101-119 ◽  
Author(s):  
Almut Iken ◽  
Robert A. Bindschadler

AbstractDuring the snow-melt season of 1982, basal water pressure was recorded in 11 bore holes communicating with the subglacial drainage system. In most of these holes the water levels were at approximately the same depth (around 70 m below surface). The large variations of water pressure, such as diurnal variations, were usually similar at different locations and in phase. In two instances of exceptionally high water pressure, however, systematic phase shifts were observed; a wave of high pressure travelled down-glacier with a velocity of approximately 100 m/h.The glacier-surface velocity was measured at four lines of stakes several times daily. The velocity variations correlated with variations in subglacial water pressure. The functional relationship of water pressure and velocity suggests that fluctuating bed separation was responsible for the velocity variations. The empirical functional relationship is compared to that of sliding over a perfectly lubricated sinusoidal bed. On the basis of the measured velocity-pressure relationship, this model predicts a reasonable value of bed roughness but too high a sliding velocity and unstable sliding at too low a water pressure. The main reason for this disagreement is probably the neglect of friction from debris in the sliding model.The measured water pressure was considerably higher than that predicted by the theory of steady flow through straight cylindrical channels near the glacier bed. Possible reasons are considered. The very large disagreement between measured and predicted pressure suggests that no straight cylindrical channels may have existed.


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