Natural factors and human modifications contributing to marsh loss in Louisiana's Mississippi River Deltaic Plain

Natural factors and human modifications contribute to the estimated annual loss of 10,200 ha of coastal land in the Mississippi River Deltaic Plain Region of south Louisiana. This paper combines information on regional geology and human-induced habitat alterations to evaluate the relative importance of human and natural factors to marsh loss. Data on marsh area and habitat type for 139 7.5-min quadrangles were calculated from maps based on aerial photographs from 1955/56 and 1978, and data on regional geology obtained from published maps were used to construct multivariate model relating initial marsh area, change in urban and agricultural area, change in canal and spoil area, canal area in 1978, depth of sediment overlying the Prairie terrace, and subdelta age to marsh loss. The model indicated that between 25.0% and 39.0% of the marsh loss that occurred during the 23-year period was related to canal and spoil construction, and between 9.5% and 12.7% was related to urban and agricultural development. These are minimal estimates of loss because they do not include many secondary effects (for example, canal orientation, saltwater intrusion, and eutrophication) that can also result in indirect loss. Depth of sediment, initial marsh area, delta lobe age by 1978 canal and spoil area interaction, and indirect effects not included in the model accounted for remaining marsh loss.     

最近2000年江苏沿海风暴潮灾害的特征

根据地方志和文献记录对江苏沿海最近2000a风暴潮灾害进行了初步分析，结果表明，风暴潮灾害在时间和空间上均发生着变化。最近600a风暴潮灾害存在21a、36a和116a三个显著的周期，并且不同时间段内发生的风暴潮灾害受不同的因素控制。.     

Coastal zone development: Mitigation,marsh creation,and decision-making

Marsh creation is currently receiving wide attention in the United States as an important tool for mitigating the impacts of development in coastal wetlands. The perception that there is no net loss in valuable coastal wetlands when development is mitigated by the creation of man-made marshes can have a substantial impact on the permitting and decision-making processes. The effective result may be the trading of natural salt marshes for man-made marshes.Techniques for marsh creation were developed by the US Army Corps of Engineers to enhance and stabilize dredge spoil materials. Most research sponsored by the Corps has been directed at determining whether these goals have been accomplished. A survey of the research indicates that there is insufficient evidence to conclude that man-made marshes function like natural salt marshes or provide the important values of natural marshes. It is necessary, therefore, for decision-makers to understand the limitations of present knowledge about man-made marshes, realistically evaluate the trade-offs involved, and relegate mitigation to its proper role in the permitting process—post facto conditions imposed on developments that clearly meet state qualifications and policies.     

Regulation for environmental protection: The Nanticoke industrial complex,Ontario, Canada

This assessment of the environmental protection regulatory system for the $2.2 billion iron and steel plant, oil refinery, and thermal generating station composing the core of the greenfield Nanticoke industrial complex is based upon: the use of governmental and industrial research in project management; technology and institutional arrangements for environmental protection; evidence of environmental changes to date; analysis of government and industrial approval files; and interviews with government, industry, and interest group representatives. Planning, regulation, and management have been reasonably efficient and effective to the beginning of the operational stage for all three major industries as of spring 1980. Of major future concern, however, is management of the cumulative and synergistic impacts of the industries and associated development on air quality as well as the lands, waters, and sensitive ecosystems of the nearby Lake Erie coast. Continuous monitoring, more comprehensive research, and better overall coordination of government, industrial, and public interests are required if Nanticoke benefits are to be achieved without undue cost to pre-project resource users within and outside the Haldimand-Norfolk region.     

Land loss in coastal Louisiana (U.S.A.)

This paper examines causes and consequences of wetland losses in coastal Louisiana. Land loss is a cumulative impact, the result of many impacts both natural and artificial. Natural losses are caused by subsidence, decay of abandoned river deltas, waves, and storms. Artificial losses result from flood-control practices, impoundments, and dredging and subsequent erosion of artificial channels. Wetland loss also results from spoil disposal upon wetlands and land reclamation projects.Total land loss in Louisiana's coastal zone is at least 4,300 ha/year. Some wetlands are converted to spoil banks and other eco-systems so that wetland losses are probably two to three times higher. Annual wetland losses in the Barataria Bay basin are 2.6% of the wetland area. Human activities are the principal determinants of land loss. The present total wetland area directly lost because of canals may be close to 10% if spoil area is included. The interrelationship between hydrology, land, vegetation, substrate, subsidence, and sediment supply are complicated; however, hydrologic units with high canal density are generally associated with higher rates of land loss and the rate may be accelerating.Some cumulative impacts of land loss are increased saltwater intrusion, loss of capacity to buffer the impact of storms, and large additions of nutrients. One measure of the impact is that roughly $8–17 × 10⁶ (U.S.A.) of fisheries products and services are lost annually in Louisiana.Viewed at the level of the hydrologic unit, land loss transcends differences in local vegetation, substrate, geology, and hydrology. Land management should therefore focus at that level of organization. Proper guideline recommendations require an appreciation of the long-term interrelations of the wetland estuarine system.     

Vegetation changes along the United States east coast following the great storm of march 1962

Regional-scale vegetation changes on Assateague Island following overwash from the Ash Wednesday Storm of 1962 were investigated using historical aerial photography. Grasses and dunes were more abundant in 1974 in areas that were overwashed, whereas areas that were not overwashed have been more extensively colonized by shrubs. The increase in shrubs on Assateague Island is attributed to the absence of a subsequent storm overwash.     

Flood problems in Bangladesh: Is there an indigenous solution?

Bangladesh, situated on the delta of the Ganges, the Brahmaputra, and the Meghna rivers, experiences two distinct types of inundations: (a) river floods resulting from excessive runoff contributed by monsoon precipitation and (b) coastal floods induced by storm surges of tropical cyclones. The river floods are normal annual events and human settlements and agricultural practices have adapted admirably well to their regimes. Abnormal floods that occur once in every few years cause serious damage to crops and properties. To minimize flood losses, a number of modern engineering projects have been constructed within Bangladesh. However, the successful solution of the problem would probably require some international collaboration for basinwide unified systems planning, since large parts of the drainage basins of Bangladesh lie beyond its borders. In the absence of such collaboration, internal resources should be utilized for the construction of smaller public projects, such aspolders, and for encouraging and reinforcing various types of indigenous adjustments to floods. There are very few successful indigenous adjustments to coastal floods. Most of the structural solutions, such as community shelters and higher embankments, are expensive public projects that are probably beyond the means of the internal resources of the country.     

An assessment of urban development into coastal wetlands using historical aerial photography: a case study

Like many other states in the USA, Virginia passed legislation to protect coastal wetlands with limited information on the rate and location of past wetlands conversions. This information, however, can be useful in the design of cost-effective and flexible programs for wetlands management, particularly when such information is used in combination with studies of the socioeconomic value of wetlands. This paper reports on the use of photogrammetric and interpretive methods to determine historical changes in wetlands use for Virginia Beach and Accomack counties, Virginia. Conclusions are drawn as to the use of such information in policy design and program monitoring.     

GOAL-ORIENTED AGRICULTURAL WATER QUALITY LEGISLATION1

ABSTRACT: While significant nonpoint source (NIPS) pollution control progress has been made since passage of Section 319 in the 1987 Water Quality Act, existing federal legislation does not provide for the most timely and cost-effective NIPS pollution reduction. In this paper, we use findings from the Rural Clean Water Program and other nationwide agricultural NIPS pollution control programs, building on legislative history to recommend a coordinated and efficient direction for agricultural water quality legislation. A collaborative framework should be established to accomplish the goals of the Clean Water Act (CWA), Coastal Zone Management Act (CZMA), and the Conservation Title of the Farm Bill. Valuable elements of the 1990 CZMA amendments that created a coastal NIPS program should be subsumed into the CWA. The CWA should reemphasize use of receiving water quality criteria and standards and should allow states flexibility to tailor basin-scale NPS program implementation to local needs. Implementation should involve targeting of NIPS pollution control efforts to critical land treatment areas and use of systems of best management practices to address these targeted water quality problems. The 1995 Farm Bill should reorient production incentives toward water quality to support the collaborative framework, implementing ecologically sound source reduction principles. The Farm Bill and the CWA should contain interrelated provisions for voluntary, incentive-assisted producer participation and fallback regulatory measures. Such coordinated national water quality and Farm Bill legislation that recognizes the need for flexibility in state implementation is supported as the most rational and cost-effective means of attaining water quality goals.     

Ten years of international scientific cooperation in fisheries,aquaculture and coastal zones: some preliminary lessons

The paper examines preliminary experiences with international scientific cooperation in fisheries, aquaculture and coastal zone issues through 90 projects in successive European Research Framework Programmes (FP4–FP6: 1994–2006). FPs had increasingly ambitious objectives in response to international commitments, such as the Convention on Biological Diversity, the Millennium Development Goals, the Johannesburg Plan of Implementation and dialogue with partner regions. Sustainable aquatic food production in the context of respect for ecosystems was a central concern. Engagement with different social actors and attention to investment in education, people and institutions enabled uptake of research results in education, innovation and some impact. The emphasis in several recent projects on more integrated analyses and knowledge products in the public domain is an encouraging response to the growing crisis of aquatic resource systems. It is suggested that significant up-scaling will be required. This might be done through institutional internalisation and better translation of research results into policy developments supportive of transitions towards sustainable production systems and ecosystem rehabilitation. Capacity building to use research in novel ways and other enabling mechanisms need to be put in place to increase societal and environmental benefits of the research.