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1.
Abstract

The Virginia Wetlands Act of 1972 provides the localities of Tidewater Virginia an opportunity to participate in the management of the state's coastal wetlands resources. This study attempts to analyze the effectiveness of this legislation and to examine the implications of a local management scheme for coastal resource management on a broader scale. Criteria are also established that can be used to evaluate the effectiveness of such a law. When examined in the light of these criteria, the Virginia Wetlands Act emerges, for the most part, as an effective piece of environmental quality legislation that has had a significant impact on wetlands destruction in the state of Virginia. During the two‐year period following the passage of the Act, wetlands losses through the permitting process showed an 18‐fold decrease from previous estimates. The Wetlands Act appears to have been generally accepted by the public and has resulted in consistently uniform decisions, which have reduced wetlands losses without unduly restricting the necessary and legitimate development of the state's wetlands.  相似文献   

2.
This article summarizes four integrated economic studies undertaken to contribute to resource preservation and restoration decisions for the Peconic Estuary System of Suffolk County, NY. Completed as part of the National Estuary Program, the studies apply distinct resource valuation methods to a wide range of resource issues. The principal goals of this article are to highlight different methodologies that may be used to assess nonmarket economic values in a coastal management context, and characterize differences in the results that one may expect from each approach. We also emphasize potential relationships among values estimated by different nonmarket methodologies, and comment on the implications of these relationships for the interpretation and use of economic value estimates.  相似文献   

3.
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.  相似文献   

4.
On the basis of annual expenditures by recreational participants and standard values of recreation days, as well as estimated sport and commercial harvests, the gross annual return from Michigan's 105,855 acres of coastal wetlands has been estimated. Analysis of fish, wildlife, and recreational values revealed that in 1977 these wetland areas generated an economic value of $489.69 per wetland acre, for a direct annual gross of $51.8 million. Specifically, these average return values per wetland acre/year, in descending order, are sport fishing ($286), nonconsumptive recreation ($138.24), waterfowl hunting ($31.23), trapping of furbearers ($30.44), and commercial fishing ($3.78). These gross annual return values were calculated in an effort to sensitize the general public to the diversity and possible magnitude of selected wetland functions.  相似文献   

5.
Note

This article is a short response to a critique by William Odum and Stephen Skjei of an earlier article by this author in this Journal entitled “Wetlands Preservation and Management on Chesapeake Bay: The Role of Science in Natural Resource Policy.”; It is a continuation of themes begun in that paper. It focuses on the question of determining the social value of wetlands preservation and the contradictory positions which ecologists fall into when discussing the value of wetlands.  相似文献   

6.
Abstract

Policymakers and analysts concerned with coastal issues often need economic value information to evaluate policies that affect beach recreation. This paper presents economic values associated with beach recreation in San Diego County generated from a recreation demand model that explains a beach user's choice of which beach to visit. These include estimates of the economic values of a beach day, beach closures, and beach amenities.  相似文献   

7.
Abstract

Redesign and reuse of waterfronts are a common experience today. Small cities presented with a deteriorating waterfront are faced with formidable economic and institutional impediments to their efforts to reverse the decline. This paper presents some design principles that if followed provide a framework for developing restoration plans. It also describes the efforts of the California State Coastal Conservancy to apply these principles to assist three small cities along California's coast to revitalize their waterfronts. Their experience indicates that in an era of limited budgets waterfront redevelopment can occur with substantial economic benefit where limited funds are applied to often small but crucial elements that result in creating waterside amenities.  相似文献   

8.
Land use/transport models and economic assessment   总被引:1,自引:0,他引:1  
This paper discusses the economic assessment of policies using land use/transport models. It argues that conventional forms of assessment focussing only on transport changes can underestimate the economic benefits of a policy. The paper argues that the benefits need to be measured by the changes of prices at the end of a trip and not just by the changes in travel costs. Models that do not estimate the changes of prices at the end of a trip cannot properly assess the impact of a policy.The model used in this paper is based on the MEPLAN software and estimates the location of households and employment and the interaction between them. It also estimates the cost of living for households and the production costs for employment. With these costs, it is possible to calculate the wider economic benefits beyond transport.The paper illustrates the assessment of policies for the Cambridge sub-region involving investment in public transport, orbital highway and congestion charging policies. The results forecast by the model are assessed in terms of the conventional cost-benefit using traveller’s surplus as benefits and compared with a wider assessment measure of compensation variation. It demonstrates that the last measure encompasses the wider benefits associated with transport policies which are not taken into account in conventional cost-benefit analysis.  相似文献   

9.
Abstract

Coastal Louisiana is currently experiencing extensive urban growth as its natural resources are exploited. Such growth is projected to continue for the foreseeable future. This article examines problems encountered in developing wetland areas for community use. The urban development process in the coastal zone is examined using a problem‐identification methodology. This methodology consists of examining each of the stages of wetlands development sequentially, determining potential problems and their results, and specifying how the regulatory system for urban development needs strengthening in order to mitigate these problems. For those development practices determined not to be regulated at all or inadequately regulated, local ordinance amendments and other restrictive measures applicable to specific development stages are proposed. The study concludes with a brief discussion of a goals‐oriented process for deriving future urban development regulations for the enhancement of regional planning efforts.  相似文献   

10.
Abstract

South Carolina has a significant stock of diked coastal wetlands, dating from the days of rice culture before the Civil War. A survey of those controlling these sites along the entire South Carolina coast reveals that many continue to be used for waterfowl hunting, with management practices becoming more intensive than they were when partial data were gathered a decade ago. It also suggests that most of the acreage involved is located in large fields, where management is more difficult and mosquito control problems are more likely. This survey also indicates that public access is limited, but that there is evidence of continuing conflict over ownership. This situation creates a persisting dilemma for coastal zone management, shaping conflicts between alternative strategies for the use of natural systems.  相似文献   

11.
This article reports the results of the travel cost model using the standard and the truncated count data models to estimate the economic value of the Similan Islands, Thailand, from SCUBA diving. The estimated consumer surplus per visit to the Similan Islands using the truncated negative binomial model was US$3,233 and the economic value of the Similan Islands from SCUBA diving was estimated to be up to US$54.96 m. This study shows that, even without non-use values, coral reefs of the Similan Islands, if properly managed and maintained, will continue to have significant value to both Thai and overseas SCUBA divers, as one of the natural treasures of the world.  相似文献   

12.
经济型数控车床自动刀架故障分析   总被引:1,自引:0,他引:1  
宋丹 《机电设备》2005,22(2):8-10
以SINUMERIK802S系统控制的经济型数控车床为例,分析了自动刀架的工作原理,介绍了其常见故障及维修方法.  相似文献   

13.
Abstract

This paper is written in response to a recent publication (Walker, 1973) which questions both the biological basis for wetlands preservation and the usefulnesss of scientific participation in the formulation of management policies. Our major points are that: (1) considerable evidence exists linking wetlands primary production to aquatic secondary production, (2) all available information suggests that large‐scale wetlands destruction results in lowered production of estuarine organisms of interest to man, (3) more than economics needs to be considered in attempts to analyze the procedures by which the wetlands controversy is to be resolved, and (4) uncertainty about the applicability of scientific findings to a particular problem situation does not destroy the usefulness of those findings in reaching a solution to a public controversy.  相似文献   

14.
The “no net wetland loss” goal has not been met in urban coastal regions where conditions continue to exacerbate wetland losses. Under the Clean Water Act (Section 404) the U.S. Army Corps of Engineers and U. S. Environmental Protection Agency share responsibility for regulating placement of fill material in wetlands. The `no discharge of fill' rules threaten coastal wetlands with continuing losses due to effects of changing climate, including rising sea levels, higher storm surges, and flooding. Where inland migration is limited by development, or where sediment accretion rates are lower than the rate of sea level rise, urban wetlands will be lost unless marsh topography is elevated. We explored regulatory and design approaches in recent Hudson-Raritan Estuary (HRE), San Francisco Bay Estuary and coastal Louisiana restorations, including creation of new marshland using dredge material. Questions related to sea level rise, ecological position within the landscape, or potential effects of extreme storm events were not addressed in the HRE restoration designs; these concerns were taken into account in other regions. We suggest benefits of marsh `replenishment' should be acknowledged in Federal regulatory policy and that consistent policies supportive of low-lying coastal marsh preservation in all regions should be enacted.  相似文献   

15.
This article introduces a theme issue of the Coastal Management Journal comprising a set of articles on the potential economic benefits from new investments in coastal ocean observing systems. We describe a methodology to estimate these benefits, and apply this methodology to generate preliminary estimates of such benefits. The approach focuses on coastal ocean observing information within ten geographic regions encompassing all coastal waters of the United States, and within a wide range of industrial and recreational activities including recreational fishing and boating, beach recreation, maritime transportation, search and rescue operations, spill response, marine hazards prediction, offshore energy, power generation, and commercial fishing. Our findings suggest that annual benefits to users are likely to run in the multiple $100s of millions of dollars. The project results should be considered first-order estimates that are subject to considerable refinement as the parameters of regional observing systems are better defined, and as our understanding of user sectors improves.  相似文献   

16.
A review of seven large landlord port authorities around the world reveals a notable diversity of pricing structures. While port authorities increasingly act as commercial undertakings, port pricing often seems to be not driven by commercial considerations. In this paper, we argue that ports can be regarded as “business ecosystems” with multiple users. This provides a valuable perspective on pricing and raises the question of whether ports can be regarded as two-sided markets. We argue this is not the case. The business ecosystem perspective provides a basis for deducing seven pricing principles for port authorities that are detailed in the paper and illustrated with cases these principles. These pricing principles are broadly follow a direct user pays approach; capture value from “non-core” tenants; price aggressively for activities with a high strategic value; differentiate pricing based on price elasticity and connectivity improvements; maximize revenue from long-term lease agreements, price port dues competitively; critically consider differentiation of charges based on environmental performance; and finally use incentives to align interests of terminal operators and shipping lines. We conclude that the ecosystem perspective is central to the understanding of pricing decisions of port authorities and that various pricing issues deserve more attention.  相似文献   

17.
Abstract

The Duplin River Estuarine Sanctuary was dedicated by Governor George Busbee of Georgia in December 1976. The sanctuary includes the entire Duplin river, related wetlands, and much of the contributing uplands, which extend over 7500 acres. Much of the upland lies on Sapelo Island, neighboring a state wildlife management area, a state natural area, and a community of black families that have lived and worked on the island for many generations. The sanctuary was acquired, in part, with funds from the National Oceanic and Atmospheric Administration, and will be managed for research and educational purposes. The management policy will be designed to avoid artificial or manipulative management control, to protect natural processes and systems, and to promote attainment of scientific objectives.  相似文献   

18.
唐浩 《上海造船》2014,(4):43-49
随着燃油价格的日益上升及废气排放的环保法规不断细化,采用双燃料发动机作为船舶动力已成为当今新船型开发中关注的焦点。液化天然气(LNG)作为船舶燃料,对减排和环保的贡献及经济实效是无可非议的。采用DF发动机作为双燃料供给系统的探讨基础,结合有关规则规范和相应的设备资料,分析DF发动机的LNG供给系统在设计中应关注的关键点,详细阐述了燃气系统各组成部分的工作原理及机舱内应采取的安全防务措施。  相似文献   

19.
Coastal areas are experiencing high levels of development, largely driven by a number of aesthetic and recreational factors, increased mobility, availability of disposable income for middle and upper income groups and the promise of job opportunities and improved economic well-being for lower income groups. As existing coastal urban nodes expand development “shifts” to less developed areas and places increasing pressure on the surrounding natural environment. This article considers the coastal zone of two municipalities in the Eastern Cape, South Africa, with similar environmental characteristics but disparate socioeconomic and governance histories. It identifies and integrates the drivers of development and land use change in the coastal zone of these municipalities by means of an adapted Driver-Pressure-State-Impact-Response (DPSIR) Framework. Development and land use change are driven by a combination of social, economic, and legislative factors that need to be considered for future management and planning in this unique dynamic system.  相似文献   

20.
Dune systems are essential to the ecological balance and sediment inputs of coastal environments and they provide numerous environmental services; however, their existence is threatened by natural and human stressors that contribute to their degradation. Future impacts are expected to be greater because of global climate change in association with further rises in sea level. Beaches and dune systems occupy large areas along the coastline of the state of Veracruz on the Gulf of Mexico. The aim of this study is to establish the intrinsic vulnerability of nine dune fields in Veracruz to current and future impacts and to assess their integrated management status. These dune–beach systems are more vulnerable to the effects of economic activities and land use change than to those induced by natural forces. Results show that six of these dune systems have medium vulnerability and an ecological conservation policy should be adopted; the other three, with high or very high vulnerability, are candidates for a restoration policy.  相似文献   

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