城市控制爆破工程的爆破事故和爆破公害研究

爆破事故和爆破公害是关于爆破工程中的安全问题 ,笔者对爆破事故中的早爆、拒爆和爆破公害中的爆破振动、爆破空气冲击波、爆破飞石进行了详细论述 ,分析了爆破事故及公害产生的原因 ,从而给出了相应的防止措施 ;进而依法采取了爆破安全管理可行办法     

ADJUSTMENT OF STREAM CHANNEL CAPACITY FOLLOWING DAM CLOSURE,YEGUA CREEK,TEXAS1

ABSTRACT: In Yegua Creek, a principal tributary of the Brazos River in Texas, surveys of a 19 km channel reach downstream of Somerville Dam show that channel capacity decreased by an average of 65 percent in a 34 year period following dam closure. The decrease corresponds with an approximately 85 percent reduction in annual flood peaks. Channel depth has changed the most, decreasing by an average of 61 percent. Channel width remained stable with an average decrease of only 9 percent, reflecting cohesive bank materials along with the growth of riparian vegetation resulting from increased low flows during dry summer months. Although large changes in stream channel geometry are not uncommon downstream of dams, such pronounced reductions in channel capacity could have long‐term implications for sediment delivery through the system.     

全面提高成人高校学报质量的思考

针对全国报刊治理整顿后多数学报由内部发行转为正式学报类期刊的新情况,本文从学报业务工作的几个方面对全面提高成人高校学报(以下简称“成高学报”)办刊质量进行了较详细的论述,旨在对成高学报的办刊工作起到一些促进作用。     

长江流域的鱼类资源及其保护对策

长江水系的鱼类约有300种,其中鲤科鱼类占半数以上,主要的经济鱼类多数属于鲤科。对不同江段的鱼类资源作了简介,并提出了相应的保护措施。上游江段以维护生物多样性,保护特有种为主,需要建立鱼类自然保护区;中游应保证主要经济鱼类的自然繁殖条件,加强珍稀鱼类的人工繁殖放流工作,同时对湖泊幼鱼资源进行保护;下游应注意保持江水质量,严格遵守工业废水排放标准;河口江段应规定幼鲟保护期,建议每年6月15日至7月31日停止一切损害幼鲟资源的渔捞作业。     

Destruction of Wetlands and Waterbird Populations by Dams and Irrigation on the Murrumbidgee River in Arid Australia

The Lowbidgee floodplain is the Murrumbidgee Rivers major wetland in southeastern Australia. From more than 300,000 ha in the early 1900s, at least 76.5% was destroyed (58%) or degraded (18%) by dams (26 major storages), subsequent diversions and floodplain development. Diversions of about 2,144,000 ML year^–1 from the Murrumbidgee River come from a natural median flow of about 3,380,000 ML year^–1 providing water for Australias capital, hydroelectricity, and 273,000 ha of irrigation. Diversions have reduced the amount of water reaching the Lowbidgee floodplain by at least 60%, from 1888 to 1998. About 97,000 ha of Lowbidgee wetland was destroyed by development of the floodplain for an irrigation area (1975–1998), including building of 394 km of channels and 2,145 km of levee banks. Over 19 years (1983–2001), waterbird numbers estimated during annual aerial surveys collapsed by 90%, from an average of 139,939 (1983–1986) to 14,170 (1998–2001). Similar declines occurred across all functional groups: piscivores (82%), herbivores (87%), ducks and small grebe species (90%), large wading birds (91%), and small wading birds (95%), indicating a similar decline in the aquatic biota that formed their food base. Numbers of species also declined significantly by 21%. The Lowbidgee floodplain is an example of the ecological consequences of water resource development. Yanga Nature Reserve, within the Lowbidgee floodplain, conserved for its floodplain vegetation communities, will lose these communities because of insufficient water. Until conservation policies adequately protect river flows to important wetland areas, examples such as the Lowbidgee will continue to occur around the world.     

Human impacts on the stream-groundwater exchange zone

Active exchanges of water and dissolved material between the stream and groundwater in many porous sand- and gravel-bed rivers create a dynamic ecotone called the hyporheic zone. Because it lies between two heavily exploited freshwater resources—rivers and groundwater—the hyporheic zone is vulnerable to impacts coming to it through both of these habitats. This review focuses on the direct and indirect effects of human activity on ecosystem functions of the hyporheic zone. River regulation, mining, agriculture, urban, and industrial activities all have the potential to impair interstitial bacterial and invertebrate biota and disrupt the hydrological connections between the hyporheic zone and stream, groundwater, riparian, and floodplain ecosystems. Until recently, our scientific ignorance of hyporheic processes has perhaps excused the inclusion of this ecotone in river management policy. However, this no longer is the case as we become increasingly aware of the central role that the hyporheic zone plays in the maintenance of water quality and as a habitat and refuge for fauna. To fully understand the impacts of human activity on the hyporheic zone, river managers need to work with scientists to conduct long-term studies over large stretches of river. River rehabilitation and protection strategies need to prevent the degradation of linkages between the hyporheic zone and surrounding habitats while ensuring that it remains isolated from toxicants. Strategies that prevent anthropogenic restriction of exchanges may include the periodic release of environmental flows to flush silt and reoxygenate sediments, maintenance of riparian buffers, effective land use practices, and suitable groundwater and surface water extraction policies.     

River systems as providers of goods and services: a basis for comparing desired and undesired effects of large dam projects

In developing countries, large dam projects continue to be launched, primarily to secure a time-stable freshwater supply and to generate hydropower. Meanwhile, calls for environmentally sustainable development put pressure on the dam-building industry to integrate ecological concerns in project planning and decision-making. Such integration requires environmental impact statements (EISs) that can communicate the societal implications of the ecological effects in terms that are understandable and useful to planners and decision-makers. The purpose of this study is to develop a basic framework for assessing the societal implications of the river ecological effects expected of a proposed large dam project. The aim is to facilitate a comparison of desired and potential undesired effects on-site and downstream. The study involves two main tasks: to identify key river goods and services that a river system may provide, and to analyze how the implementation of a large dam project may alter the on-site capacity and downstream potentials to derive river goods and services from the river system. Three river goods and six river services are identified. River goods are defined as extractable partly man-made products and river services as naturally sustained processes. By four main types of flow manipulations, a large dam project improves the on-site capacity to derive desired river goods, but simultaneously threatens the provision of desirable river goods and services downstream. However, by adjusting the site, design, and operational schedule of the proposed dam project, undesirable effects on river goods and services can be minimized.     

The Cost of Developing Site-Specific Environmental Regulations: Evidence from EPA's Project XL

The flagship of the Environmental Protection Agency's regulatory reinvention initiative, Project XL has been touted as a regulatory blueprint for a site-specific, performance-based pollution-control system, but widespread complaints about the costs of the program beg the question of whether the costs of tailoring regulations to individual facilities are manageable. To address this question, this paper presents original survey data on a sample of 11 XL projects. We find that the fixed costs of putting in place XL agreements are substantial, averaging over $450,000 per firm. While stakeholder negotiations are widely cited as the principal source for these costs, we find that they actually arise mainly from interaction between participating facilities and the EPA. Moreover, EPA management problems are perceived by our survey respondents as having inflated project development costs. Finally, we find that the key factors that explains differences in costs across XL projects are the scope and complexity of the project proposal. These findings suggest that Project XL favors large firms that can afford to pay significant project development costs, that EPA management problems must be resolved to reduce costs, and that there may be a significant economic bias against complex and innovative proposals—precisely the type of proposals that Project XL was designed to foster in order to improve the efficiency of the regulatory system.     

Monitoring, enforcement, and the choice of environmental policy instruments

How to choose among the dozen policy instruments available to environmental management agencies has been a matter of concern and debate among environmental economists for the entire life of the profession – nearly four decades. The ability, or lack of it, to measure the quantities or observe the actions made "enforceable" by particular policy instruments ought clearly to be central to this choice. However, all too often the monitoring problem has been assumed away. When it is reintroduced in realistic forms, we find, not surprisingly, that some favorite policy instruments, such as pollution charges, are not applicable to some important problems, such as runoff pollution from farms; that marginal subsidies, by changing the burden of proof, may no longer be symmetric with charges; and that the apparent freedom from monitoring requirements of the newly fashionable instrument involving the public provision of information about firms or products is "paid for" by our inability to say anything about its performance on other dimensions that are also of interest. Electronic Publication     

Reinventing Environmental Regulation from the Grassroots Up: Explaining and Expanding the Success of the Toxics Release Inventory

/ The success of the Toxics Release Inventory (TRI) stands in stark contrast to most other environmental regulations in the United States. Between its inception in 1988 and 1995, releases of chemicals listed on the TRI have declined by 45%. We argue the TRI has achieved this regulatory success by creating a mechanism of "populist maxi-min regulation." This style of regulation differs from traditional command-and-control in several ways. First, the majorrole of public agencies is not to set and enforce standards, but to establish an information-rich context for private citizens, interest groups, and firms to solve environmental problems. Second, environmental "standards" are not determined by expert analysis of acceptable risk, but are effectively set at the levels informed citizens will accept. Third, firms adopt pollution prevention and abatement measures in response to a dynamic range of public pressures rather than to formalized agency standards or governmental sanction. Finally, public pressure ruthlessly focuses on the worst polluters-maximum attention to minimum performers-to induce them to adopt more effective environmental practices. TRI has inadvertently set in motion this alternative style of regulation that has, in turn, dramatically reduced toxics emissions in the United States. By properly understanding the mechanisms that drive TRI's accomplishments, more intentional public policy designs can expand the system of populist maxi-min regulation and achieve even more rapid toxics reduction.