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651.
Charles T. Roman Robert A. Zampella Andrew Z. Jaworski 《Journal of the American Water Resources Association》1985,21(6):1005-1012
Wetland protection regulations and guidelines often require the delineation of precise wetland boundaries on a case-by-case basis. In this study, conducted in the New Jersey Pinelands, an ecological characterization of vegetation composition, soil and hydrologic relationships along upland to wetland Pinus rigida - dominated transittions provided the basis for a multiparameter approach to wetland boundary delineation. The transitional data set was analyzed by direct gradient analysis, cluster analysis and ordination. It is concluded that vegetation composition can be a principal factor in delineating wetland boundaries along natural upland to wetland transitions. However, where distinct vegetation changes are not observed, a feature of our study sites, a multiparameter approach should be used. 相似文献
652.
Hydrologic modeling as a predictive basis for ecological restoration of salt marshes 总被引:4,自引:0,他引:4
Roads, bridges, causeways, impoundments, and dikes in the coastal zone often restrict tidal flow to salt marsh ecosystems.
A dike with tide control structures, located at the mouth of the Herring River salt marsh estuarine system (Wellfleet, Massachusetts)
since 1908, has effectively restricted tidal exchange, causing changes in marsh vegetation composition, degraded water quality,
and reduced abundance of fish and macroinvertebrate communities. Restoration of this estuary by reintroduction of tidal exchange
is a feasible management alternative. However, restoration efforts must proceed with caution as residential dwellings and
a golf course are located immediately adjacent to and in places within the tidal wetland. A numerical model was developed
to predict tide height levels for numerous alternative openings through the Herring River dike. Given these model predictions
and knowledge of elevations of flood-prone areas, it becomes possible to make responsible decisions regarding restoration.
Moreover, tidal flooding elevations relative to the wetland surface must be known to predict optimum conditions for ecological
recovery. The tide height model has a universal role, as demonstrated by successful application at a nearby salt marsh restoration
site in Provincetown, Massachusetts. Salt marsh restoration is a valuable management tool toward maintaining and enhancing
coastal zone habitat diversity. The tide height model presented in this paper will enable both scientists and resource professionals
to assign a degree of predictability when designing salt marsh restoration programs. 相似文献
653.
654.
Brian K. Gullett William P. Linak Abderrahmane Touati Shirley J. Wasson Staci Gatica Charles J. King 《Journal of Material Cycles and Waste Management》2007,9(1):69-79
Air emissions and residual ash samples were collected and analyzed during experiments of open, uncontrolled combustion of
electronic waste (e-waste), simulating practices associated with rudimentary e-waste recycling operations. Circuit boards
and insulated wires were handled separately to simulate processes associated with metal recovery. The average emissions of
polychlorinated dibenzodioxins and dibenzofurans (PCDD/PCDFs) were 92 ng toxic equivalency (TEQ)/kg [n = 2, relative standard deviation (RSD) = 98%] and 11 900 ng TEQ/kg (n = 3, RSD = 50%) of the initial mass of the circuit boards and insulated wire, respectively. The value for the insulated wire
is about 100 times higher than that for backyard barrel burning of domestic waste. The emission concentrations of polybrominated
dibenzodioxins and dibenzofurans (PBDD/PBDFs) from the combustion of circuit boards were 100 times higher than for their polychlorinated
counterparts. Particulate matter (PM) sampling of the fly ash emissions indicated PM emission factors of approximately 15
and 17 g/kg of the initial mass for the circuit boards and insulated wire, respectively. Fly ash samples from both types of
e-waste contained considerable amounts of several metallic elements and halogens; lead concentrations were more than 200 times
the United States regulatory limits for municipal waste combustors and 20 times those for secondary lead smelters. Leaching
tests of the residual bottom ash showed that lead concentrations exceeded U.S. Environmental Protection Agency landfill limits,
designating this ash as a hazardous waste. 相似文献
655.
Wokje Abrahamse Linda Steg Charles Vlek Talib Rothengatter 《Journal of environmental psychology》2007,27(4):265-276
In this multidisciplinary study, an Internet-based tool was used to encourage households (N=189) to reduce their direct (gas, electricity and fuel) and indirect energy use (embedded in the production, transportation and disposal of consumer goods). A combination of tailored information, goal setting (5%), and tailored feedback was used. The purpose of this study was to examine whether this combination of interventions would result in (i) changes in direct and indirect energy use, (ii) changes in energy-related behaviors, and (iii) changes in behavioral antecedents (i.e. knowledge). After 5 months, households exposed to the combination of interventions saved 5.1%, while households in the control group used 0.7% more energy. Households exposed to the interventions saved significantly more direct energy than households in the control group did. No difference in indirect energy savings emerged. Households exposed to the interventions adopted a number of energy-saving behaviors during the course of the study, whereas households in the control group did so to a lesser extent. Households exposed to the interventions had significantly higher knowledge levels of energy conservation than the control group had. It is argued that if the aim is to effectively encourage household energy conservation, it is necessary to examine changes in energy use, energy-related behaviors and behavioral antecedents. 相似文献
656.
657.
Charles C. Morris Paul M. Stewart Thomas P. Simon 《Journal of the American Water Resources Association》2007,43(2):295-307
Abstract: This study evaluated biological integrity expectations of fish assemblages in wadeable streams for the Alabama portion of the Choctawhatchee River watershed using a multimetric approach. Thirty‐four randomly selected stream sites were sampled in late spring 2001 to calibrate an index of biotic integrity (IBI). Validation data were collected during the spring 2001, and summer and fall of 2003 from disturbed and least‐impacted targeted sites (n = 20). Thirty‐five candidate metrics were evaluated for their responsiveness to environmental degradation. Twelve metrics were selected to evaluate wadeable streams and four replacement metrics were selected for headwater streams. Scores that ranged from 58 to 60 were considered to be representative of excellent biotic integrity (none found in this study), scores of 48‐52 as good integrity (31% of the sites in this study), 40‐44 as fair (43%), 28‐34 as poor (21%), and 12‐22 as very poor (5%). Of the four stream condition categories (urban, cattle, row crop, and least impacted), the IBI scores for urban and cattle sites differed significantly from least‐impacted sites. Row crop sites, although not significantly different from least‐impacted, tended to have greater variability than the other categories. Lower IBI scores at both urban and cattle sites suggest that the IBI accurately reflects stream impairment in the Choctawhatchee River drainage. 相似文献
658.
Michael Greenberg Karen Lowrie Joanna Burger Charles Powers Michael Gochfeld Henry Mayer 《Journal of Environmental Planning and Management》2007,50(2):187-209
A survey of 1351 people who lived within 50 miles of one of six US Department of Energy nuclear weapon sites showed that the vast majority of residents prefer strong public health surveillance and land use controls. The sample was stratified so that the same number of responses was obtained at each site. The strongest correlates of wanting the DOE to restrict on-site activities and maintain and expand its surveillance programs were worries about DOE activities on the site, as well as how those activities could damage the off-site environment. Notably, the exceptions, that is, those who demanded less from the DOE and were not particularly worried about the DOE's activities, tended to live near the site, many worked there or knew people who did, and had high socio-economic status, and trusted the DOE. The findings are mostly, but not entirely, consistent with expectations drawn from the risk perception and organizational trust literatures. The challenge is how to establish a stewardship program that represents a consensus among state and local government, community advisory boards and the public that remediation can go on at the same time that some waste is managed on-site until suitable technologies can be safely deployed, which at some sites means 100 years or in perpetuity. 相似文献
659.
Charles Berenbrock 《Journal of the American Water Resources Association》2006,42(2):387-394
A genetic algorithm (GA) was used to reduce cross section data for a hypothetical example consisting of 41 data points and for 10 cross sections on the Kootenai River. The number of data points for the Kootenai River cross sections ranged from about 500 to more than 2,500. The GA was applied to reduce the number of data points to a manageable dataset because most models and other software require fewer than 100 data points for management, manipulation, and analysis. Results indicated that the program successfully reduced the data. Fitness values from the genetic algorithm were lower (better) than those in a previous study that used standard procedures of reducing the cross section data. On average, fitnesses were 29 percent lower, and several were about 50 percent lower. Results also showed that cross sections produced by the genetic algorithm were representative of the original section and that near‐optimal results could be obtained in a single run, even for large problems. Other data also can be reduced in a method similar to that for cross section data. 相似文献
660.