海平面上升对沿海工程顶面高程确定的影响

随着海平面的上升,沿海地区的年最高水位的极值及重现期已发生变化,对沿海工程顶面高程的确定产生了重大影响。以吴淞为例,以码头顶面高程为研究对象,用纯经验曲线法计算重现期;并根据IPCC第5次评估报告假定情景下的海平面上升情况,计算各情景下港口码头顶面高程的变化。结果表明海平面上升对码头顶面高程确定的影响非常明显,对顶面高程较低的码头的影响尤为显著。     

Land use implications of sea level rise: A case study at myrtle beach,South Carolina

Abstract

the prospect of global warming and consequent sea level rise will have important implications for coastal communities. this article examines the land use implications of alternate sea level rise scenarios on the city of myrtle beach, south carolina. current trends as well as high and low sea level rise scenarios are superimposed on the city's beach profile and near shore contours to estimate the type and value of land development likely to be impacted.

It is found that losses associated with accelerated sea level rise would be particularly high in the city's hotel district and that overall property loss could range from 21 to 60% of the city's total property value. to lessen these potential losses, coastal communities such as myrtle beach must choose among one of three policy options including: (1) barricade the beach, (2) raise the land, and (3) implement a strategic retreat. specific alternatives within each of these options are explored in turn. the article concludes that successful development plans will incorporate ground rules sensitive to and consistent with dynamic coastal processes.     

Port authorities view state coastal management programs

Abstract

An estuarine sanctuary is a store of public values due to the ecological, cultural, recreational, aesthetic, historic, and economic services provided by the preserve. These values may be expected to increase over time because of (1) growth in the population demanding estuarine services, (2) growth in the willingness to pay for such services, and (3) growth in the actual quality and quantity of services which are provided by a protected natural system. Thus an estuarine sanctuary will be more valuable to future generations than to current generations. When weighing the cost and benefits of a preservation or development decision, a preservation decision which seems currently undesirable may in fact be socially beneficial when growth in the value of estuarine services is included.     

Perceptions of the performance of state coastal zone management programs in the United States. II. Regional and state comparisons

A mail survey of coastal user groups, academics, and state coastal zone management program managers was conducted to determine the perceptions of the performance of state coastal zone management programs relative to the protection of coastal resources, the management of coastal development, the improvement of public access, and the management of coastal hazards. Information on the perceived importance of the selected issues to each of the 24 states being studied was also solicited. Findings on the perceptions of various categories of interest groups, academics, and program managers with respect to the overall performance of state coastal zone management programs in the four issue areas were presented in an earlier article, “Perceptions of the Performance of State Coastal Zone Management Programs in the United States”; (Knecht et al., 1996). The present article draws on a subset of these data—the responses from the coastal user groups and the academics—and presents the findings at the regional and individual state level. In terms of perceived performance of state coastal zone management programs on a regional basis relative to the selected issue areas, the highest rating went to the Great Lakes region for its management of public access. However, the North Atlantic region received the highest performance rating for the three other issue areas: protection of coastal resources, management of coastal development, and management of coastal hazards. Looking at state performance with regard to the coastal issues judged to be of most importance to the states—the protection of coastal resources and the management of coastal development—respondents indicated that states should improve their performance in both areas, with the greatest need related to the management of coastal development. Overall, the states of the North Atlantic, Great Lakes, and South Atlantic regions were perceived to be performing somewhat better relative to the four issue areas than the states in the Pacific and Gulf of Mexico regions. While the data do not shed light on the reasons for these regional differences, we suggest that, in the case of the Pacific region at least, the differences could be associated with higher expectations among the resident population with regard to environmental quality in general and coastal management in particular.     

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.     

Greenhouse effect,sea level rise,and coastal zone management

Abstract

Increasing concentrations of carbon dioxide and other gases are expected to warm the earth several degrees in the next century by a mechanism known as the greenhouse effect. Such a warming could cause sea level to rise two to five feet by expanding ocean water, melting mountain glaciers, and perhaps eventually causing polar glaciers to melt and slide into the oceans.

A rise in sea level of even three feet could cause substantial erosion of beaches and coastal wetlands, increased flooding, and intrusion of saltwater into rivers, bays, and aquifers. Fortunately, many of the adverse consequences can be avoided by taking timely measures in anticipation of sea level rise. Nevertheless, many coastal zone managers are reluctant to take these measures until the prospect of sea level rise becomes more certain.

This article examines the implications of future sea level rise and identifies anticipatory measures that may be appropriate today in spite of current uncertainties.     

Evolution of coastal hazards policies in the United States

The ocean and Great Lakes coasts of the United States are experiencing widespread economic and environmental damage from coastal flooding and erosion. During this century, public response to such coastal hazards has evolved haphazardly in response to particular disasters. Over time, however, the range of response has broadened as research has helped to refine public understanding of physical coastal processes, and specific disasters have been studied before longer term forms of institutional response have been formulated. Earlier reliance on engineered shoreline protection has been supplemented by beach nourishment, flood insurance, building and land use regulations, coastal zone planning, and other approaches. This article interprets the evolution of such public policy innovations in terms of a model that depicts the interaction of spatially differentiated systems of physical, legal, and cultural phenomena in the coastal context.     

The status of coastal zone management in South Africa

Abstract

In this article, an overview of the status of coastal zone management (CZM) in South Africa is presented. Firstly, it provides background to the development of various initiatives to promote sustainable use of coastal resources within the context of sociopolitical changes in South Africa. Thereafter, it examines the progress made with respect to key attributes underpinning most CZM programs. Finally, it identifies obstacles to achieving effective CZM in South Africa and makes recommendations to address these shortcomings. The review reveals that whilst considerable progress has been made in certain areas of program development, such as resource conservation and pollution control, there are several gaps and inadequacies within existing efforts. These include the absence of a clear policy to guide efforts, lack of coordination amongst government departments involved in CZM, as well as inadequacies in our legal and administrative system. The promulgation of a Coastal Zone Management Act and the establishment of a Coastal Unit charged with the coordination and review of all activities impinging on coastal resources are amongst the recommendations made.     

Assessment of coastal zone issues in the Republic of Korea

Abstract

The physical characteristics of Korea have had a profound impact on the uses of the coastal zone that have, in turn, been determined by and reinforced the nation's economic development strategy. While coastal zone management in many developed economies is more heavily oriented toward environmental protection and the resolution of user conflicts, policies for coastal zone management in Korea have emphasized the role of coastal space and other resources for economic development and industrial needs. Increasing demand for land reclamation to provide ever‐increasing industrial sites and human settlements, traditional and future needs of the fishery, and concern for the environment have led to a vast array of competition and, finally, often to conflicts. The basic pattern of coastal zone use in Korea has changed from the linear expansion of coastal zone to integrated coastal uses. An increased number of critical coastal zone issues and interactions was reflected in the creation of new governance that dealt with coastal zone resources and environment.     

Policy considerations for wetland wastewater treatment in the coastal zone: A case study for Louisiana

Two major environmental problems currently affecting the Louisiana coastal zone are a high rate of wetland loss and high levels of surface water pollution. The application of secondarily treated wastewater to wetlands can be a means of dealing with both of these problems. The benefits of wetland wastewater treatment include improved surface water quality, increased accretion rates to balance a high relative water level rise due mainly to subsidence, improved plant productivity and habitat quality, and decreased capital outlays for conventional engineering treatment systems. Wetland treatment systems can, therefore, be designed and operated to restore deteriorating wetlands. Hydrologically altered wetlands, which are common in the Louisiana coastal zone, are appropriate for receiving municipal and some types of industrial effluent. While the U.S. Environmental Protection Agency has determined wetland wastewater treatment is effective in treating municipal effluent, it has discouraged the use of natural wetlands for this purpose. At the same time, funds are being used for the construction of artificial wetlands to treat municipal effluent. In the Louisiana coastal zone, however, wetlands are deteriorating and disappearing due to hydrological alteration and a high rate of relative sea level rise. If no action is taken, these trends will continue. Effluent discharge to existing wetlands should be incorporated into a comprehensive management plan designed to increase sediment and nutrient input into subsiding wetlands in the Louisiana coastal zone, improve water quality, and result in more economical waste‐water treatment. The authors believe that the Louisiana example serves as a model for other coastal areas especially in light of projections of accelerated sea level rise.     

Armoring Against Coastal Climate Adaptation in the US: A Massachusetts Perspective

Massachusetts, like many coastal states in the US, stands to be impacted from climate-induced sea level rise. As a result, climate-sensitive coastal policy instruments are critical for providing adequate adaptation options, including an option to allow coastal features to migrate inland. But the migration of coastal features is under threat due to extensive private armoring. This essay highlights specific regulatory instruments at the federal and state level dealing with hard armoring using Massachusetts as an example. It argues specific federal and state regulations legitimize and incentivize hard armoring over other coastal land use planning methods. The current level of armoring in Massachusetts is highlighted and implications under current federal and state policy frameworks are explained. Suggestions for coastal states planning for sea level rise are discussed, including the need for state planning to take the lead. Recommendations for changes at the federal level are also highlighted.     

Vulnerability of Coastal Resort Cities to Mean Sea Level Rise in the Mexican Caribbean

We evaluated the potential economic impacts of increasing sea level rise (SLR) along the Mexican Caribbean where there are major gaps in our understanding of the mechanisms controlling flooding duration and frequency associated to future ecological and economic impacts. We determined the negative economic impact of SLR on infrastructure in the largest urban centers (Cancun, Isla Mujeres, Playa del Carmen, Puerto Morelos and Cozumel) in the state of Quintana Roo (Mexico) that are considered the largest tourism “hot spots” (resort cities) in the country. The tourism industry in this coastal area injects >8 billion dollars year^?1 to the Mexican economy. Our conservative economic assessment regarding the impact of SLR, under a 1?m scenario for all coastal cities is $330 million USD. Further projections for worst scenarios (SLR >2 m) show a non-linear trend where the cost of inaction can reach up to $1.4 billion USD (2?m SLR scenario) and $2.3 billion USD (3?m SLR scenario). This potential loss of infrastructure, as construction cost, is staggering and represents a robust baseline to start evaluating with more detail future impacts of climate variability and change on the Mexican Caribbean coastline.     

Integrating visual management into the coastal zone planning process: The Massachusetts experience

Abstract

This paper concerns the limitations on integrating visual management into the coastal zone planning process as exemplified by the Commonwealth of Massachusetts, a state with a strong tradition of “home rule”; and a CZM implementation program based on a “networking”; of existing state authorities. The implications of the Massachusetts experience are that: (a) management of esthetic resources at the state level continues to be much less of a priority than management of ecological resources such as wetlands or floodplains; (b) visual management has yet to engender a strongly supportive constituency beyond that concerned with historic preservation; (c) project review focusing on visual impacts may be a more appropriate activity for local rather than state government; and (d) the technical aspects of visual management or impact assessment are far more advanced than their political acceptability. Political realities, together with the decision that implementation of the program should be based on a networking of existing authorities, thus determined the degree to which visual management could be incorporated into the state's program. As a result, the program's principal instruments of visual management became a strengthening of existing programs such as Wild and Scenic Rivers, reliance on wetland protection statutes to indirectly protect natural scenic values, and the use of the federal consistency provisions of the Coastal Zone Management Act to foster focused growth patterns through provision of publicly funded infrastructures. Esthetically oriented project review, with the exception of potential impacts on historic sites, was left to the discretion of local government, and a technical assistance program was created to provide funding or professional skills to communities interested in developing their own esthetic controls or design review processes. Maine, Rhode Island, and other New England states have followed a similar course.     

The cost of not holding back the sea: Toward a national sample of economic vulnerability

Abstract

National and regional estimates of U.S. economic vulnerability to greenhouse‐induced sea‐level rise are produced from a sample of 30 discrete regions scattered evenly along the coastline. Scenarios that envision 50 cm, 100 cm, and 200 cm of greenhouse‐induced sea‐level rise are considered. They can be expected to place $39.2, $65.6, and $133.3 billion, respectively, (1989 dollars) of existing development in jeopardy through 2050, and $133.3, $308.7, and $909.4 billion through 2100. Sampling error and consideration of the uncertainty with which we currently view future greenhouse‐induced sea‐level rise places the 25th and 75th percentile values of expected cumulative vulnerability at $38.5 and $76.7 billion through 2050 and $132.6 and $362.4 billion through 2100. Not surprisingly, the southeast displays the largest potential vulnerability, with the northeast ranking second above both the Gulf coast and the west coast.     

浙江沿海特征潮位与工程设计水位关系

针对岛屿地区长期潮位资料缺乏,给工程设计水位确定带来一定困难的问题,利用浙江沿海16个潮位站一年的潮位资料,推算本海域各站特征潮位及设计水位,并采用线性相关分析法对特征潮位与设计水位间关系进行研究,得到两者间规律性的成果,可为浙江沿海港口工程前期规划、设计等阶段估算工程设计水位提供参考。     

Coastal erosion and sea level rise: Implications for ocean beach and San Francisco's westside transport project

Abstract

One of the consequences of sea level rise resulting from the greenhouse effect is increased coastal erosion. This article discusses a model of erosion that can be used to estimate the response of beaches to sea level rise. The model is applied to Ocean Beach, California, with particular attention to the consequences of accelerated erosion for the San Francisco Westside Sewer Transport. Results obtained show that erosion produced by accelerated sea level rise could cause substantial damage to the structure. Large expenditures on beach nourishment will be required to protect the transport and the recreational value of the beach.     

不同期验潮数据用于余水位差分水位推算的可行性分析

利用中短期验潮资料调和分析获得11个主要分潮的调和常数实现水位推算的方法,已在海洋测绘、疏浚工程测量等领域得到推广。但不进行全部站点的同步验潮测量,仅收集不同期历史验潮数据进行分析,获得的潮汐调和常数难以满足水深测量水位改正的精度要求。提出2种调和常数优化方法,通过增强不同期验潮数据调和常数的相关性,提高水位推算的精度,并以实例验证不同期验潮数据用于余水位差分水位推算的可行性。     

广东省沿海地区年最高设计潮位计算与分析*

选取广东省沿海28个潮位站(或水位站)作为计算基本站,对基本站潮位资料进行了可靠性、一致性和代表性检验,资料系列均满足有关规范规定的要求。根据情况对各站潮位资料进行了极大值处理,对基本站按极值Ⅰ型和PⅢ型分布律进行了频率计算,通过适线对比选用适当的线型。广东省沿海年最高潮位均值变化趋势总体上呈自东向西增大的趋势,与潮差大小的变化趋势基本一致。广东省沿海Cv值的大小受风暴潮的影响较大,因此,沿海站位Cv值一般大于河口站位,多大于0.20。广东省沿海年最高设计潮位总体上呈东低西高的态势,以潮差最大,遭受风暴潮影响最多的粤西地区年最高设计潮位最高,以潮差较小的港口、汕尾站年最高设计潮位最低。     

国内外港口工程水位确定方法对比

按照国内港口工程规范工程水位计算的要求,需要使用长短期实测水位资料。而海外工程项目实测数据匮乏,资料深度不满足工程水位的计算要求。以埃及苏赫纳项目为依托,对港口工程水位进行计算,阐明国内外港口工程水位计算方法的异同。     

The use of digital filter initialization to diagnose the mesoscale circulation and vertical motion in the California coastal transition zone

A dynamical method of initializing the primitive equations is tested and used to diagnose the three-dimensional circulation associated with jets and eddies as found in the California coastal transition zone (CTZ). The initialization method, referred to as digital filter initialization (DFI), was recently developed by [Monthly Weather Review 120 (1992) 1019] for use in an intermittent data assimilation system in the atmosphere. The ability of DFI to recover the mesoscale ageostrophic circulation associated with finite amplitude jets and eddies in the ocean is first demonstrated using control data produced by simulations with a primitive equation model. The DFI method is then applied to synoptic hydrographic data collected during several California CTZ surveys in the summer of 1988. The diagnostic results indicate the existence of jets, eddies, and filaments in the CTZ domain with maximum horizontal currents of the order of 0.6 m/s at the surface. Currents associated with such jets and filaments are coherent to a depth of over 500 m. The surface currents associated with a prominent cool filament are generally confluent, and weakly convergent on average, along the 270 km offshore extent of the filament. Meanders in the jet display convergence and downwelling upstream of pressure troughs and divergence and upwelling downstream of the troughs. Maximum vertical velocities at 100 m are of the order of 10 m/day. This result is consistent with independent estimates of subduction rates made from biological studies in this and similar coastal filaments in the CTZ program.