Coastal Facilities Research Articles

低天端突堤による砂礫海岸の漂砂制御の評価

A numerical simulation of the beach changes on the Seisho coast was carried out using a contour-line-change model considering changes in the grain size. The applicability of the simulation model to a gravel-sand beach with protruding rocks was verified by comparing the calculated and observed changes after storm waves generated by T0709. The sand transport controls achieved by different types of coastal facilities were estimated and compared under an imaginary wave condition that could occur in future. A newly-designed groin with a low crown height was found to be most effective in preserving a straight coastline, if a sufficient amount mount of sand will be supplied by beach nourishment.

A Review of Assessment and Adaptation Strategy to Climate Change Impacts on the Coastal Areas in South China

This paper reviews assessment of climate change impacts on economy, society and ecological environment in the coastal areas of South China based on published literatures; it also proposes suitable adaptation strategies and countermeasures. Review shows that climate change has resulted in sea level rise in the coastal areas of South China, increasing the occurrence and intensity of storm surges, aggravating the influence of saltwater intrusion, coastal erosion, urban drainage and flood control, threatening the coastal facility and infrastructures, inundating lowland areas, offsetting mudflat silting, and degrading mangroves and coral reef ecosystem. Therefore, in order to reduce the adverse effects of climate change and to support the sustainable development in the coastal areas of South China, it is critical to improve the monitoring and early warning system, enhance prevention criteria, fortify coastal protection engineering, strengthen salt tide prevention, and reinforce the ecological restoration and protection. CitationDu, Y.-D., X.-H. Cheng, X.-W. Wang, et al., 2013: A review of assessment and adaptation strategy to climate change impacts on the coastal areas in South China.Adv. Clim. Change Res., 4(4), doi: 10.3724/SP.J.1248.2013.201.

First attempt to assess the viability of bluefin tuna spawning events in offshore cages located in an a priori favourable larval habitat

Most of the Atlantic bluefin tuna caught by the purse-seine fleet in the Mediterranean Sea are transferred alive into transport cages and towed to coastal facilities where they are fattened. This major fishery is targeting aggregations of reproductive bluefin tuna that continue spawning within the transport cages. Our study is the first attempt to assess the viability of the spawning events within transport cages placed offshore in a priori favourable locations for larval survival. The study was conducted in June 2010 in the Balearic Sea, a main spawning area for bluefin tuna in the Mediterranean. The location of two transport cages, one with wild and one with captive tuna, coincide with the situation of the chlorophyll front using satellite imagery as a proxy for the salinity front between resident surface waters and those of recent Atlantic origin. The results showed that bluefin tuna eggs were spawned almost every day within the two cages but few or no larvae were found. The expected larval densities estimated after applying mortality curves to the daily egg densities observed in the cages were higher than the sampled larval densities. The trajectories of the eggs after hatching estimated from a particle tracking model based on observed geostrophic currents and a drifter deployed adjacent to the cage suggest that larvae were likely to be caught close to the cages within the sampling dates. Spawning events in captive tuna in transport cages may hatch into larvae though they may experience higher mortality rates than expected in natural populations. The causes of the larval mortality are further discussed in the text. Such studies should be repeated in other spawning areas in the Mediterranean if spawning in cages located offshore in areas favourable a priori for larval survival is likely to be considered a management measurement to minimize the impact of purse-seine fishing on tuna.

정현형 지형과 다양한 외부흐름에 의한 반사

The resonant reflection caused by sinusoidally varying submerged structure and wave could protect coastal facilities from wave attack by reducing wave energy. Water waves deform by not only bottom topography but also interaction with shear currents. In this study, a resonant reflection by a sinusoidally varying topography with various shear currents is investigated. The water depth and the slope of shear currents are represented by a finite number of tiny steps. The proper numbers of steps are proposed and the effects of evanescent modes are shown.

Evaluating environmental joint extremes for the offshore industry using the conditional extremes model

Understanding extreme ocean environments and their interaction with fixed and floating structures is critical for the design of offshore and coastal facilities. The joint effect of various ocean variables on extreme responses of offshore structures is fundamental in determining the design loads. For example, it is known that mean values of wave periods tend to increase with increasing storm intensity, and a floating system responds in a complex way to both variables.Specification of joint extremes in design criteria has often been somewhat ad hoc, being based on fairly arbitrary combinations of extremes of variables estimated independently. Such approaches are even outlined in design guidelines. Mathematically more consistent estimates of the joint occurrence of extreme environmental variables fall into two camps in the offshore industry — response-based and response-independent. Both are outlined here, with emphasis on response-independent methods, particularly those based on the conditional extremes model recently introduced by (Heffernan and Tawn, 2004), which has a solid theoretical motivation. We illustrate an application of the conditional extremes model to joint estimation of extreme storm peak significant wave height and peak period at a northern North Sea location, incorporating storm direction as a model covariate. We also discuss joint estimation of extreme current profiles with depth off the North West Shelf of Australia. Methods such as the conditional extremes model provide valuable additions to the metocean engineer's toolkit.

A new criterion and probabilistic approach to the performance assessment of coastal facilities in relation to their adaptation to global climate change

“Maximum allowable wave height” is proposed as a new criterion for assessing the performance of coastal facilities when planning a strategy for adapting these facilities to global climate change. Since it considers the prevention of wave overtopping and the structural strength of coastal facilities such as seawalls or breakwaters as measures of performance, this new criterion can represent the reduction in performance of coastal facilities due to sea level rise or of a greater frequency of tropical cyclones induced by global climate change. This study proposes a probabilistic approach to assess the performance of coastal structures. Using this approach, the time-dependent encounter probability, the return period, and modified residual life are introduced as new indices for making decisions on adaptation strategies. A useful characteristic of these indices is that they make possible the direct comparison of different physical quantities such as wave overtopping and structural strength. Case studies were conducted in order to verify the validity of this approach. The proposed approach is considered to be beneficial in planning an adaptation strategy related to global climate change. A more accurate assessment can be made through case studies of its application.

Paradigm shift in the regulatory application of safety management systems to offshore facilities

The April 2010 Deepwater Horizon tragedy and release from the Macondo Well resulted in a re-examination of the existing regulatory framework, significant modifications to the structure and function of key regulatory agencies, and the application of new Safety Management System requirements to offshore facilities in United States waters. Late-2010 witnessed the evolution of both prescriptive and performance-based regulations designed to address the direct and underlying causes of this tragedy. The objective of this article is to briefly review these new regulatory requirements and illustrate how they are related to the application of other Safety Management Systems, for both offshore and onshore facilities. The common themes, objectives, and overlaps of specific onshore and offshore Safety Management System elements was examined, and tips on how these overlaps can be used to more effectively (and sensibly) implement these programs is discussed. This article also outlined successful Safety Management System programs that are being applied by various state agencies to onshore and offshore coastal facilities, and derived lessons-learned from these programs that may assist in the implementation of related federal programs. © 2016 American Institute of Chemical Engineers Process Saf Prog 35: 317–329, 2016

Potential impact of climate change at five Japanese beaches

Yoshida, J., Udo, K., Takeda, Y., and Mano, A., 2013. Potential impact of climate change at five Japanese beachesCoastal erosion caused by sea level rise is a serious problem over the world. Future sea level rise will almost certainly accelerate through the 21st century. Although its extent remains uncertain, some predictions expect the increase to be between up to 30 and 180 cm by 2100 (Nicholls and Cazenave, 2010). Several studies show that sea level rise is responsible for long-term beach erosion. Moreover, change of wave height and non-climate-related processes such as ground subsidence amplify coastal vulnerability associated with climate change. It is a pressing issue to predict shoreline change considering the fact that 10% of the global population lives in the coastal regions within 10 m elevation. This study estimates the potential impact of climate change in terms of the effects of: sea level rise; wave height variation; and land subsidence by comparing the past coastline evolutions at five beaches in Japan. The past long-term shoreline change was found to be related to coastal protection measures according to Japan's national policy (Coast Act). Notable erosion was resulted from the construction of coastal facilities that blocked coastal sand drift and the decrease of sediment supply from rivers caused by dam building from 1950 to 1990. Since 1990, shoreline has relatively unchanged because some measures, such as beach nourishment, groins and detached breakwaters, have worked to conserve sand beaches. The estimation results showed that shoreline would retreat over 15 m due to sea level rise and up to 5 m due to wave height variation at the five beaches by 2100. Projection of ground subsidence is uncertain because its rate varies depending on natural forces and human activities. This study suggests that sea level rise would have much greater impact on beach erosion compared with wave height variation and ground subsidence.

既設港湾・海岸構造物の維持管理の視点にもとづく安全率の確率評価手法－波力および土圧に対する外的安定問題－

既設港湾・海岸構造物の維持管理の視点にもとづく安全率の確率評価手法－波力および土圧に対する外的安定問題－

Buried and Submerged Greek Archaeological Coastal Structures and Artifacts as Gauges to Measure Late Holocene Seafloor Subsidence off Calabria, Italy

This synthesis integrates recently acquired archaeological and geological data with earlier documented observations to shed light on the subsidence of ancient Greek coastal facilities in southern Italy. These are now positioned between former shorelines and inner shelf sectors at five Calabrian margin localities. Submergence of coastal to inner shelf facilities has resulted in part from sea‐level rise by about 2 m associated with glacio‐hydro‐isostatic factors since archaic to classic Greek time. This phenomenon alone, however, does not explain the wide variation of measured subsidence rates from site‐to‐site. The marked lowering of coastal site substrates by seismo‐tectonic activity (including extensional fault motion), stratal readjustments at depth, and compaction of underlying sediment sequences is significant. Four of the subsided facilities are positioned near emerged Calabrian areas where prevailing Holocene average annual land uplift rates range to ˜1.0 mm/yr; at the fifth, near Hipponion, terrains have risen by nearly 2 mm/yr. In marked contrast, submerged and/or buried structures record the following late Holocene long‐term average rates of coastal margin subsidence: Sybaris‐Thuri on the Taranto Gulf margin (˜0.5–1.0 mm/yr); Hipponion‐Vibo Valentia along the Tyrrhenian coast (˜0.8 to ˜3.2 mm/yr); and Locri‐Epizefiri, Kaulonia, and Capo Colonna on Calabria's Ionian margin (˜1.6, ˜1.6–2.4, and ˜4.0 mm/yr, respectively). © 2012 Wiley Periodicals, Inc.

Merging tsunamis of the 2011 Tohoku‐Oki earthquake detected over the open ocean

Tsunamis often travel long distances without losing power and severely devastate some coastal areas while leaving others with little damage. This unpredictable situation has been a major challenge for accurate and timely tsunami forecasting to facilitate early‐warning and possible evacuations of affected coastal communities without disturbing the lives of others. Here we show evidence from satellite altimetry observations of the 2011 Tohoku‐Oki earthquake‐induced tsunami that sheds light on this issue. Three satellites observed the same tsunami front, and for the first time, one of them recorded a tsunami height about twice as high as that of the other two. Model simulations, based on the GPS‐derived earthquake source and constrained by measurements of seafloor motions near the hypocenter, confirm that the amplified tsunami is one of several jets formed through topographic refraction when tsunamis travel along ocean ridges and seamount chains in the Pacific Ocean. This process caused the tsunami front to merge as it propagates, resulting in the doubling of the wave height and destructive potential in certain directions. We conclude that the potential of merging tsunamis should be emphasized in mapping tsunami hazards and assessing risk levels at key coastal facilities.

Oil Spill Response Information System and Contingency Planning for Guinean Waters

Abstract Over the years there has been many well documented cases of major oil pollution from leaked offshore oil rigs, ships in distress and from coastal oil facilities. In response to concerns about the possibility of a major oil spillage occurring along the coast of Guinea, the Guinean government drew up a plan and organisation. The purpose of this research was to develop Guinean Marine Oil Spill Response Information System. To do this, we simulated an oil spill concentration transport. The results show that the numerical model in oil spill accident simulation is important in allowing setting up of possible response and contingency planning. From the results we conclude that, the search strategies for futures responses and contingency planning to possible oil spill case in Guinean coasts has been clarified. Implications of research findings allow international community to consider reasonable estimation of spilled oil trajectory with limited environmental input data.

Targeted Therapies Take Aim Against Lung Cancer and Melanoma

More than 300 staff from the Centers for Disease Control and Prevention (CDC) and the Agency for Toxic Substance and Disease Registry (ATSDR) are monitoring health threats from the oil spill in five Gulf states through the National Poison Data System, which has taken 651 calls related to exposure to the oil spill as of July 8, and BioSense, which reports that there have been no increases in specific syndromes at 86 coastal health care facilities. The CDC’s National Institute for Occupational Safety and Health (NIOSH) is providing technical assistance in training clean-up workers, creating rosters of workers to track them for illnesses later if necessary, and coordinating the collection of analysis of injury and illness data BP is required to report. CDC is also reviewing the results of the EPA’s daily environmental samples to determine whether the level of detected pollutants constitutes a health hazard. BP has pledged $500 million to the Gulf of Mexico Research Initiative to study the impact of the spill on the environment and public health. And the National Institutes of Health announced it will devote $10 million to support research on potential human health effects. Research and surveillance can’t start soon enough, stressed John C. Bailar III, MD, PhD, professor emeritus in the Department of Health Studies at the University of Chicago. “Every day matters. People will move away, memories will fade or change, and environmental samples will be altered with the passage of time.” Also crucial, Bailar said, is for a single organization to direct the research efforts “so that all the data can be assembled to tell a convincing story.” And research needs to be coordinated locally, said Maureen Y. Lichtveld, MD, MPH, professor and chair of the department of environmental health sciences at Tulane University School of Public Health and Tropical Medicine. “What we don’t need, frankly, is a repeat of Hurricane Katrina where researchers descended on New Orleans and did all sorts of studies, but the community was left without the answers it needed. We need meaningful data that will let communities take the next steps.”

Biomass logistics as a determinant of second‐generation biofuel facility scale, location and technology selection

AbstractFeedstock logistics, as dictated by biomass physical properties, location, and distribution, as well as transportation infrastructure, were shown to be a primary determinant of the scale, location, and technology selection of any future biorefineries. The maximum capacity of both biochemical‐ and thermochemical‐based second‐generation biofuel facilities was established based on feedstock logistics including delivery mode (road, rail, or ship), maximum number of deliveries by mode, feedstock type (whole logs, chips, pellets, or bio‐oil), and biofuel yield from those feedstocks. The world's largest ethanol plant, pulp mill, coal‐based power plant, and oil refinery were used to approximate maximum plant size for different technologies, and to set an upper limit on the number of deliveries logistically possible for each transport mode. It was apparent that thermochemical conversion to transportation biofuels was favored for large, multimodal coastal facilities that are able to receive imported biomass in the form of feedstock intermediates, such as pellets and bio‐oil (maximum capacities of 2844 and 6001 million liters gasoline equivalent (MLGE) respectively). Biochemically‐based conversion processes, primarily due to smaller economies of scale and the typical use of higher moisture content and undensified feedstocks, such as whole logs and chips, are better suited for smaller facilities (maximum 1405 and 1542 MLGE, respectively) that rely on local feedstocks delivered by truck and/or rail. It was also apparent that optimization of the feedstock‐intermediate‐product chain, including biomass densification for transportation and high conversion yield, is essential if the scale of the any second‐generation biofuels facility is to be maximized. Copyright © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd

A New Index for Performance Assessment of Coastal Facilities for Adaptation to the Global Warming

A New Index for Performance Assessment of Coastal Facilities for Adaptation to the Global Warming

Hazard assessment of underwater landslide-generated tsunamis: a case study in the Padang region, Indonesia

Submarine landslides can generate local tsunamis with high run-ups, posing a hazard to human lives and coastal facilities. Both ancient (giant Storegga slide off Norwegian coast, 8200 B. P.) and recent (Papua New Guinea, 1998) events show high potential danger of tsunamigenic landslides and the importance of mitigation efforts. This contribution presents newly discovered landslides 70 km off Padang (Western Sumatra, Indonesia) based on recent bathymetry measurements. This highly populated city with over 750,000 inhabitants exhibits high tsunami vulnerability due to its very low elevation. We model tsunamis that might have been induced by the detected landslide events. Estimations of run-up heights extrapolated from offshore tsunami amplitudes for Padang and other locations in the northern Mentawai fore-arc basin yield maximum values of about 3 m. We also provide a systematic parametric study of landslide-induced tsunamis, which allows us to distinguish potentially dangerous scenarios for Padang. Inside the fore-arc basin, scenarios involving volumes of 0.5–25 km³ could endanger Padang. Apart from slide volume, the hazard distribution mainly depends on three landslide parameters: distance to Padang, water depth in the generation region, and slide direction.

A Floating Backbone for Internet over the Ocean

Satellite-based Internet access, the preferred solution for remote locations on the ocean, either offers a low-bandwidth connection or is very expensive to deploy. A backbone structure that provides ocean-wide Internet coverage could provide an alternative to satellite uplinks. With a wide-area network forming a mesh of nodes using floating and moving objects as well as coastal facilities, the network would use next-generation long-range surface radio technology to provide medium- to high-bandwidth Internet access. To achieve high-bandwidth Internet access under these circumstances, the backbone must leverage state-of-the-art sensor network technology, autonomous routing mechanisms, and self-organizing abilities.

Impact between fluids and solids. Comparison between analytical and FEA results

Abstract Theoretical and numerical analyses of the dynamic force acted on structures by fluid-like debris flows (d.f.) or fluids are presented. Current analyses of the interaction between d.f. and structures usually take into account a modified hydrodynamic pressure or a multiple of the hydrostatic pressure, to determine the impact force. A close examination of analytical and experimental results, mainly pertaining to hydraulic and coastal engineering, regarding the impact of water waves against coastal facilities, however, reveals that these simplified assumptions are not supported by rational presumptions. Numerical (FE) analyses have been therefore carried out and their results compared to the available theoretical and numerical results in the literature. The importance of the impulsive phase of the impact phenomenon, especially if a planar d.f. front face is parallel to the impacted structure, is put into evidence. Proposed FEA results highlight the role of fluid's speed, density and compressibility in the general problem of the impact of fluids against structures.

Developing an effective tsunami warning system: Lessons from the 1960 Chile earthquake tsunami for New Zealand coastal communities

The magnitude 9.5 earthquake on 22 May 1960 in southern Chile was the largest instrumentally recorded earthquake in the 20th century. It generated a tsunami that swept the shores of Chile and radiated out across the Pacific, with the major loss of life in Chile and, despite warnings being issued, in both Hawai'i and Japan. The absence of a Pacific‐wide tsunami warning system at the time meant that the tsunami struck New Zealand without an official warning being issued. Fortunately, there was no loss of life despite widespread damage to coastal facilities. A large aftershock occurred in Chile 3 days later (25 May) and fears about a tsunami from this event resulted in the broadcasting of a nationwide warning on radio in New Zealand. Newspapers of the day reported that thousands of people around the country were evacuated, making this the largest and most widespread evacuation in New Zealand's history. Almost the entire population of Whitianga, Waihi Beach, Whakatane, Ohope, and Opotiki were moved to high ground for several hours and, in many other communities, people self‐evacuated from coastal fringes. After the event, there was much discussion in the newspapers of the need to improve both warnings and public awareness of the hazard, and of the appropriate response to warnings. Over the 40 years from 1960 up to the 26 December 2004 Indian Ocean tsunami, public awareness of New Zealand's tsunami risk and preparedness had waned. Since 2004, the renewed focus on tsunami has built on a range of improvements in emergency management policies and practices, and the lessons identified from the event paved the way for a number of new initiatives to get underway to enhance the New Zealand's tsunami warning capacity and capability.

Prediction of 3-D Beach Changes using BG-Model after Beach Nourishment in Lake Kasumigaura

In Lake Kasumigaura, lakeshore vegetations and sandy beach have been devastated in recent years. To recover the sandy beach in Okisu Area in this lake, beach nourishment has been planned with coastal facilities to stabilize the beach, such as groins, detached breakwaters, artificial reefs and artificial headlands. To evaluate the effect of these facilities, BGmodel proposed by Serizawa et al.(2006) was applied for predicting the three dimensional topographic changes after the nourishment. It is concluded that the most appropriate method is to stabilize the beach using a headland.