海岸工程的允许越浪量

对于防护海岸陆地的护岸和海堤等,通常并不要求其顶高程在高潮大浪时完全不越浪,而是要求将其越浪量控制在一定的允许范围（允许越浪量）内。为此设计时要计算各式建筑物在不同波浪作用下的越浪量,还要制定允许越浪量的标准。根据国内外对海岸工程的两种允许越浪量的研究,综述已有允许越浪量的主要研究成果,可供工程设计参考。     

An integrated water/sediment approach to study plankton (a case study in the southern Adriatic Sea)

In marine coastal areas many planktonic species produce resting stages (cysts) that sink to the bottom. Integrated sampling from both the water column (to collect active stages), and sediments (to collect cysts), could be useful to achieve more complete information about plankton composition.In the framework of the “INTERREG II Albania-Italy Project” an oceanographic survey was carried out aboard the r/v “Italica” from 20 to 31 October 2000. The survey interested the northern Albanian coast (Gulf of Drin) and the northern Apulian coast (Gulf of Manfredonia) on the opposite sides of the South Adriatic Sea. The plankton was collected from 14 stations. A total of 188 categories were recognized in plankton samples. Among those categories, 130 species were recognized (87 of phytoplankton, 43 of microzooplankton), and only 53 (40.8%) resulted common to both the Adriatic sides. A total of 69 cyst morphotypes were recognized in sediment samples; 38 of them were classified at the level of species. A statistical analysis of the micro-zooplankton species abundance showed a segregation of the two areas better than that obtained with the phytoplankton. Cyst distribution in the sediments showed a good gulf-segregation too. In addition, they allowed us to find complementary information, particularly for dinoflagellates. The most abundant species in the water column were not equally dominant as resting stages in the sediments. Sediment sampling allowed further information about the composition of the plankton communities, and suggested us to search for a new method to enhance the yield of less abundant cysts.     

A 2D long term advection—dispersion model for the Channel and southern North Sea Part B: Transit time and transfer function from Cap de La Hague

A 2D advection-dispersion model, already described and validated, has been used to provide information about water trajectories, transit times, transfer factors and transfer functions in the Channel and North Sea, south of 57 ° N.It shows that a fast vein of water moves parallel to the coast and reaches the northern limit of the model in one year. Along the coast, a few dozen kilometers from this vein, transit times increase by 2–4 months.Tidal gyres in the Channel recirculate waters and dissolved elements for about 2 yr, and in all it generally takes 3 yr for a specific discharge made at La Hague to completely leave the area under study.The transfer factor was depicted and found to be of the order of 10⁻⁵ m.k.s.One utilization of the transfer function could be to predict the future evolution of water content in the months and years following a discharge in these coastal waters.     

Indicators for Evaluating the Impact of Artificial Islands on the Barcelona Coast

Artificial islands have been constructed next to large cities due to the need for extra space in highly populated areas. These emerged structures have been used by many countries as platforms for developing infrastructure (airports, harbors, highways, etc.), rebuilding ecological areas, and creating new spaces for tourism or residential areas. In this study, two state-of-the-art numerical models for wave propagation and nearshore circulation are used to simulate the effects of an emerged artificial island on the Barcelona coast. Several sea indicators (wave height, intensity and direction of currents, and mean water level) are analyzed to assess the changes likely to be induced by an artificial island. Three different situations are studied and the indicators are compared across the different tests to obtain information that can be used in the planning process of these structures. In two-meter wave conditions, the tests show that wave height is generally reduced in the sheltered area, which leads to improved safety for beach users (bathing is prohibited when wave height exceeds the two-meter threshold). However, the numerical models also reveal that velocities in the sheltered area usually decrease, which must be controlled to prevent stagnation in the bathing area.     

风暴潮条件下越浪水体对堤顶附加直墙的作用

为研究极端条件下浅水大波对沿海建筑物的作用,采用物理模型试验的方法,在波浪水槽中开展风暴潮条件下越浪水体对斜坡堤堤顶附加直墙的作用试验,得出波浪作用在堤顶附加直墙上压强分布的规律,并基于动量方程得出越浪量和压强、流速之间的相互关系。结果表明,不同越浪量条件下直墙作用力随时间呈不同的变化规律,当越浪量较小时呈单峰分布,越浪量较大时呈双峰分布;越浪水体对直墙的水平作用力符合韦布尔分布;越浪水体上挑角度先随越浪量增加而增加,当越浪量较大时再随越浪量增加而略微减小,最大值在75°左右。     

Measurement of ocean temperatures using instruments carried by Antarctic fur seals

The study aimed to test the utility of instruments deployed on marine mammals for measuring physical oceanographic variation and, using this method, to examine temperature variation in the coastal waters around South Georgia. There was a significant correlation between temperature measurements made using a towed undulating oceanographic recorder (UOR) and concurrent measurements from time-depth recorders (TDRs) fitted to lactating Antarctic fur seals foraging from the coast of South Georgia. Congruence was found at horizontal spatial scales from 0.01°×0.01° to 0.5°×0.5° (degrees of latitude and longitude), and at a vertical scale of 10 m. However, there was no significant correlation between temperature measured by TDRs in the top 5 m and sea surface temperature (SST) measured by satellite remote sensing. TDR data provided information about temperature variation vertically through the water column, and through time. The UOR data were used to recalibrate the TDR data in order to correct for the slow response time of the TDR thermistor relative to the speed of seal movements through the water column. Seasonal temperature variation was apparent, and temperatures also varied between regions, and with bathymetry. These results were consistent with the current interpretation of the coastal oceanography around South Georgia. In particular, the relationship between on- and off-shelf waters showed larger amounts of warmer surface water in a region in which more run-off was to be expected. The study also showed that Antarctic fur seals concentrate their activity in regions of colder, and presumably oceanic, water. Such instrumented animals could provide near real time data for assimilation into ocean models.     

Seasonal upwelling underneath the Tsushima Warm Current along the Japanese shelf slope

Seasonal upwelling variations are examined in the eastward coastal boundary branches of the Tsushima Warm Current (TWC). The climatological pattern and the fundamental hydrographic structure of the seasonal appearance of cold water are revealed by analyzing the temperature profile data around the Japanese shelf area. Seasonal maps of temperature at the intermediate layer around 200 m depth show the rise of the main pycnocline along the Japanese coast due to seasonal subsurface cooling from May to September. The cold water areas appear around the strong curvature in the continental shelf break. These areas are confined to the south of the TWC thermal front, i.e., to the coastal boundary region. The seasonal appearance of the localized cooling areas implies that the seasonal upwelling is induced by horizontal variations in shelf topography and the intensifying TWC from May to September.     

Cultural Models of the Coast in Australia: Toward Sustainability

Cultural models of the coast affect—and are affected by—our marine ethics, frameworks for coastal ownership, and management practices. The coast can be seen as an ecosystem with intrinsic values, a commodity that can be bought and sold, a community place where people meet, a landscape with aesthetic appeal, a productive system that generates profits, a property to be managed, or a spiritual realm that relates to proper order and reverence. Each of these cultural constructions interacts with the others and this can create conflicts over rights and responsibilities. Each construction has implications for who should manage the coast, to what ends, and by what means. This article explores the negative and positive implications of seven cultural models to the Australian coast and makes suggestions about the value of Australian Indigenous and sustainability perspectives to a durable human relationship with the coast. Examples are drawn from recent coastal developments in Australia, such as Native Title debates, the marine protected area process, and Coastcare.     

斜坡堤上平均越浪量计算方法的比较

针对海岸工程中的越浪量问题,国、内外学者进行过大量研究,提出了多种计算平均越浪量的方法,但由于考虑的影响因素不同,计算结果常有较大差异.目前,在我国的海堤、护岸等海岸工程设计中,多按"允许越浪量"为控制条件初步确定堤顶高程,再由物理模型试验加以验证.本研究基于三维波浪模型试验,综合针对斜坡堤上平均越浪量的主要研究成果,...     

不同质量级配堤心石对波浪传播影响的试验研究

通过物理模型试验的方法,采用规则波研究了深水斜坡堤堤心石物理特性的变化对于波浪传播的影响。在无越浪的前提下,主要讨论了斜坡堤透浪系数与入射波周期、入射波高、质量级配等因素的关系。根据上述研究成果,拟合得到了考虑无因次参数H_i/d、gT~2/d及堤心石结构B/D_(50)等因素的透浪系数计算经验公式,为今后防波堤工程建设及科学研究提供一定的参考依据。     

直墙建筑物后不规则波越浪压力试验研究*

越浪作用直接关系到直墙建筑物的安全、顶高程的决定等问题.采用物理模型试验,研究不规则波越浪压力在不同基床肩宽、基床高度、胸墙顶端相对静水面高度与波浪要素等因素影响下的规律.通过最小二乘法和非线性多元回归分析,拟合出无因次越浪压力和各主要影响因素相互关系的计算公式,供工程设计参考与进一步研究.     

海岸地区长周期地貌模型研究进展

海岸地区的长周期地貌演变关系到了人类对海岸带资源的合理开发、保护及可持续利用。研究者不断改进和提高了海岸地区长周期地貌模型的适用性和可靠性。文章从发展概况、时空尺度、计算原理、信息约减技术以及模型应用等方面简述了海岸地区长周期地貌模型的研究进展,并认为模型的理论、技术还可进一步提高,模型的应用范围还可拓展到更大尺度。     

Western Australia's nonstatutory approach to coastal zone management: An evaluation

Abstract

Western Australia is fortunate that there have been few natural disasters on the coast. However, low levels of coastal erosion during the 1970s demonstrated the need to establish coastal zone management in that state of Australia. The erosion was quickly contained because private ownership to the high water mark is almost nonexistent, private property being set back behind coastal reserves along most of the coast. The provision of coastal reserves has been part of a deliberate nonstatutory coastal planning and management approach. As a result Western Australia has been able to use existing acts, coordination between existing government agencies, and coastal policies rather than enact specific coastal legislation to manage the coast.     

Natural Coast Protection and Use in China: Implications of Resource Protection “Redline” Policies

A significant proportion of China's coast has been developed for aquaculture, salt industry, ports and harbors, industry, reclamation, and so on. The stated target, of keeping at least 35% mainland coast in natural status until 2020, in the National Marine Functional Zoning Plan (2011–2020) is unlikely to be realized. This article analyzes the current protection and utilization of mainland coast and discusses effects of coastal over-development. The use of the “redline” policy in natural resources protection, including forests, cultivated land, freshwater and marine ecology is reviewed, and the “redline” policy is advised to be adopted in natural coast protection through such measures as total length control, buffer zones, regional control, inter-region engagement, and efficient artificial coastal areas use and restoration.     

Managing Beach Amenities to Reduce Exposure to Coastal Hazards: Storm Water Pollution

Despite posted warnings and educational campaigns warning about the health risks associated with storm water pollution, swimmers continue to swim in coastal areas polluted by storm water runoff. This study uses a simple spatial model of beach visitation to show how beach amenities and storm drains influence the way in which beach goers choose to locate themselves at beaches in Santa Monica Bay, California. The estimated models indicate that passive means of preventing exposure to marine pollution (e.g., posted signs) could be made significantly more effective if combined with the active management of other beach amenities. Similar methods also could be used to reduce risks to swimmers from other hazards including riptides and boat traffic.     

Tributyltin in marine sediments and Philippine green mussels (Perna viridis) in Manila Bay

Tributyltin (TBT) is a pollutant, mainly introduced to the environment as insecticides, fungicides, bactericides, wood preservatives and marine antifouling agent. Concentrations of TBT and its degradation products were isolated from the bivalve Perna viridis and marine sediments collected from selected coastal areas along Manila Bay. In all samples, the extremely toxic TBT compound was detected, calculated as Sn. In sediments, measured concentration ranged from the limit of detection of 0.5 to 9.0 ng Sn g^?1. Highest levels of TBT were observed at the inner and northern part of the bay, adjacent to coastal areas of varying land and water use (i.e., aquaculture, fishpond, mangrove forests, industrial establishments, and ports). However, the levels decrease near the bay entrance. Accumulation in this area can also be deduced from the movement of the prevailing wind and hydrodynamic behavior of the bay during the time of sampling, which transports suspended sediments from the eastern coast of Manila to the northern coast of Bulacan. In green mussels, the levels of TBT ranged from 2.1 to 8.9 ng Sn g^?1. While these values are relatively low, concentrations as low as 0.659 ng Sn g^?1 have been reported to be toxic to molluscs. The environmental levels of organotin species determined in the samples are comparatively low by global standards. Nevertheless, there is a need to estimate the levels of TBT in coastal waters and its associated uses, to evaluate the effectiveness of imposed regulation prohibiting the application of organotin compounds (OTs) as biocides in antifouling agents on ships and aquaculture facilities.     

Vulnerability of Caribbean Island Cemeteries to Sea Level Rise and Storm Surge

The Intergovernmental Panel on Climate Change reports that rising seas by the end of this century will increase the severity of coastal flooding and erosion. The Caribbean region is home to many small islands that are vulnerable to sea level rise and storm surge. Much of the literature examining impacts of sea level rise in the Caribbean focuses on ecosystems, infrastructure, and recreation. Few studies have examined how sea level rise will impact historic and culturally important places. In an effort to address this research gap, geographic information systems and crowd-sourced, georeferenced photographs were used to build a first-of-its-kind database of 542 Caribbean small island cemeteries. Vulnerable cemeteries were then identified based upon elevation, proximity to the ocean, and the coastal profile. Over one-fifth of the cemeteries surveyed are within 100 m of the coast. The highest concentrations of vulnerable cemeteries are on flat islands such as the Cayman Islands. Yet, some mountainous islands such as Saint Martin also have potentially vulnerable cemeteries. These findings suggest that the bereaved, cemetery managers, and managers of coastal areas that have cemeteries may have additional considerations when making long-term decisions about where and how to bury the deceased.     

Radioactive tracers as a tool in coastal oceanography: An overview of the MAST-52 project

Radionuclides (⁹⁹Tc, ¹²⁵Sb, ⁹⁰Sr, ¹³⁷Cs) discharged from La Hague in France have been used to trace advection and dispersion of water masses in the “European Coastal Current” from the English Channel to the Baltic. Time-series of radionuclide measurements in water samples taken in the English Channel, at the Netherlands coast, in the German North Sea sector and in Danish waters have been compared with reported discharge values. The prospects for using ¹²⁹I measured by accelerator mass spectrometry (AMS) as an oceanographic tracer have been evaluated as positive. The ⁹⁹Tc analytical procedure have been improved and background levels of ⁹⁹Tc, ¹³⁷Cs and ⁹⁰Sr in open North Atlantic seawater without influence from European discharges have been determined. An intercomparison programme have documented the quality of the measured ⁹⁹Tc and ¹²⁵Sb data. Transit times and transfer factors from La Hague to different locations in the study area have been estimated. It is concluded, that 10% of the La Hague discharge is transported through Kattegat and that 1/3 of the inflowing Kattegat bottom water originates from the coastal current. Three fundamentally different numeric models have been further developed under the project. The measured data have then been compared with values simulated by the three models. Models as well as measured data indicate, that a close coastal transport with longer transit times and often higher concentrations than seen in the open water main current is taking place. This coastal transport is important when contaminant transport is monitored. It is concluded, that the collected data gives a unique opportunity to evaluate models on advection and dispersion of coastal water masses and contaminants. The database will be made available as a tool for the evaluation of such models.     

Classification of Beach Erosion Vulnerability on the Yucatan Coast

Beach erosion can have important socioeconomic and environmental consequences, particularly in tropical regions where tourism is a significant source of income. Although caused by natural processes, erosion is often aggravated by disorderly anthropogenic modification of the coast and extreme events. In Yucatan, Mexico, increasing urban development and deficient coastal management strategies as well as hurricanes have affected beach stability. This has highlighted the need for adequate coastal planning and policies that ensure the protection of key coastal ecosystems, such as beaches and sand dunes. To address this, a methodology to classify the coast according to its vulnerability is presented in this work. This methodology assumes that morphological features are indicators of beach evolution and the processes driving it and that these can be associated with different levels of vulnerability. The features considered are beach width, dune vegetation, anthropogenic pressure, and shoreline orientation, which were analyzed through aerial images and a multicriteria evaluation. It was observed that the most vulnerable areas are found near the most developed parts of the coast, where narrow beaches with little dune vegetation dominate. It is expected that this index will be of use to coastal planners and decision makers, particularly in the identification of critical zones.     

Managing Shoreline Change Under Increasing Sea-Level Rise in Ghana

Relative sea-level rise will affect vulnerable coastal communities globally. Quantifying this effect on the coastal environment and infrastructure provides critical information that enables coastal managers to develop sustainable mitigation and adaptation measures. Modeling applications have enabled the past, present, and future trends in shoreline morphology to be investigated in detail. Predictive numerical models depend largely on the reliability of the input data. This article reports on using the Soft Cliff and Platform Erosion (SCAPE) numerical model to simulate future shoreline evolution trend in the central Accra coast in Ghana. The model input parameters include historic shoreline recession rates, wave data, tidal data, bathymetry, beach volume, beach topography, historic relative sea-level rise rates, and the shoreline orientation. The data fed the SCAPE numerical model which simulated the emergence of soft rock shore profiles over timescale of decades to centuries, to project future positions of the central Accra shoreline for the next 100 years under different scenarios of climate change. Simulated future shoreline positions overlaid on a 2005 orthophoto map of Accra enabled vulnerable areas and infrastructure at risk to be identified. It emerged that a highly populated community in central Accra will be inundated by 2065, while the Rivera beach resort will be eroded from 2035. A natural fish landing site in Osu (suburb in Accra) will be lost from 2045. The study has demonstrated that considerable ecological, economic, social, and national losses should be expected within the next century. Shoreline change management options should be explored to help mitigate the expected impact of the sea-level rise.