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451.
Chin A Daniels MD Urban MA Piégay H Gregory KJ Bigler W Butt AZ Grable JL Gregory SV Lafrenz M Laurencio LR Wohl E 《Environmental management》2008,41(6):893-903
This article reports a study of the public perception of large wood in rivers and streams in the United States. Large wood
is an element of freshwater aquatic ecosystems that has attracted much scientific interest in recent years because of its
value in biological and geomorphological processes. At the heart of the issue is the nature of the relationship between scientific
recognition of the ecological and geomorphological benefits of wood in rivers, management practices utilizing wood for river
remediation progress, and public perceptions of in-channel wood. Surveys of students’ perceptions of riverscapes with and
without large wood in the states of Colorado, Connecticut, Georgia, Illinois, Iowa, Missouri, Oregon, and Texas suggest that
many individuals in the United States adhere to traditionally negative views of wood. Except for students in Oregon, most
respondents considered photographs of riverscapes with wood to be less aesthetically pleasing and needing more improvement
than rivers without wood. Analysis of reasons given for improvement needs suggest that Oregon students are concerned with
improving channels without wood for fauna habitat, whereas respondents elsewhere focused on the need for cleaning wood-rich
channels for flood risk management. These results underscore the importance of public education to increase awareness of the
geomorphological and ecological significance of wood in stream systems. This awareness should foster more positive attitudes
toward wood. An integrated program of research, education, and policy is advocated to bridge the gap between scientific knowledge
and public perception for effective management and restoration of river systems with wood. 相似文献
452.
Morrice JA Danz NP Regal RR Kelly JR Niemi GJ Reavie ED Hollenhorst T Axler RP Trebitz AS Cotter AM Peterson GS 《Environmental management》2008,41(3):347-357
A better understanding of relationships between human activities and water chemistry is needed to identify and manage sources
of anthropogenic stress in Great Lakes coastal wetlands. The objective of the study described in this article was to characterize
relationships between water chemistry and multiple classes of human activity (agriculture, population and development, point
source pollution, and atmospheric deposition). We also evaluated the influence of geomorphology and biogeographic factors
on stressor-water quality relationships. We collected water chemistry data from 98 coastal wetlands distributed along the
United States shoreline of the Laurentian Great Lakes and GIS-based stressor data from the associated drainage basin to examine
stressor-water quality relationships. The sampling captured broad ranges (1.5–2 orders of magnitude) in total phosphorus (TP),
total nitrogen (TN), dissolved inorganic nitrogen (DIN), total suspended solids (TSS), chlorophyll a (Chl a), and chloride; concentrations were strongly correlated with stressor metrics. Hierarchical partitioning and all-subsets
regression analyses were used to evaluate the independent influence of different stressor classes on water quality and to
identify best predictive models. Results showed that all categories of stress influenced water quality and that the relative
influence of different classes of disturbance varied among water quality parameters. Chloride exhibited the strongest relationships
with stressors followed in order by TN, Chl a, TP, TSS, and DIN. In general, coarse scale classification of wetlands by morphology (three wetland classes: riverine, protected,
open coastal) and biogeography (two ecoprovinces: Eastern Broadleaf Forest [EBF] and Laurentian Mixed Forest [LMF]) did not
improve predictive models. This study provides strong evidence of the link between water chemistry and human stress in Great
Lakes coastal wetlands and can be used to inform management efforts to improve water quality in Great Lakes coastal ecosystems. 相似文献
453.
Kirstin Dow Richard L. Murphy Gregory J. Carbone 《Journal of the American Water Resources Association》2009,45(1):187-197
Abstract: The increasing availability of web mapping tools creates new opportunities to bridge decision‐makers’ climate information needs with technical capabilities. These new tools, however, raise familiar, unresolved issues related to cartographic representation. Using an on‐line drought mapping tool, this study seeks to understand which spatial unit best meets the desire drought managers have for “local” information, their comprehension of uncertainties introduced in mapping information at local scales, and their willingness to trade off accuracy for information at a desired unit. We found that the most useful local map information includes regional context and boundaries which present their local area of interest. Even among this experienced, well‐educated, professional group, those who had not taken a GIS or cartography class did not fully recognize the role of interpolation in creating and introducing uncertainty to some drought maps. Those who did recognize the uncertainty introduced by interpolation still strongly favored maps that provided estimated values for all areas vs. station point accuracy. Mapping poses a unique set of challenges to communicating risk and uncertainty. As more decision‐support efforts incorporate web mapping, greater attention is needed to assure that users understand the tradeoffs between accuracy and precision in creating local information, the imprecision of boundaries, as well as the limits of forecasts. Clearly conveying spatial accuracy and uncertainty is a challenge that merits greater attention in using maps to communicate drought and other environmental risk information. 相似文献
454.
Gregory D. Mueller Anita M. Thompson 《Journal of the American Water Resources Association》2009,45(5):1116-1126
Abstract: Runoff from urban catchments depends largely on the amount of impervious surface and the connectivity of these surfaces to the storm sewer drainage system. In residential areas, pervious lawns can be used to help manage stormwater runoff by intercepting and infiltrating runoff from impervious surfaces. The goal of this research was to develop and evaluate a simple method for estimating the reduction in stormwater runoff that results when runoff from an impervious surface (e.g., rooftop) is directed onto a pervious surface (e.g., lawn). Fifty‐two stormwater runoff reduction tests were conducted on six residential lawns in Madison, Wisconsin during the summer of 2004. An infiltration‐loss model that requires inputs of steady‐state infiltration rate, abstraction (defined here as surface storage, vegetation interception and cumulative total infiltration minus steady‐state infiltration during the period prior to steady‐state), and inundated area was evaluated using experimental data. The most accurate results were obtained using the observed steady‐state infiltration rates and inundated areas for each test, combined with a constant abstraction for all tests [root mean squared (RMS) difference = 1.0 cm]. A second case utilized lawn‐averaged steady‐state infiltration rates, a regression estimate of inundated area based on flow‐path length, and lawn‐specific abstractions based on infiltration rate (RMS difference = 2.2 cm). In practice, infiltration rates will likely be determined using double‐ring infiltration measurements (RMS difference = 3.1 cm) or soil texture (RMS difference = 5.7 cm). A generalized form of the model is presented and used to estimate annual stormwater runoff volume reductions for Madison. Results indicate the usefulness of urban lawns as a stormwater management practice and could be used to improve urban runoff models that incorporate indirectly connected impervious areas. 相似文献
455.
456.
Tianfeng Chai Gregory R. Carmichael Youhua Tang Adrian Sandu Andreas Heckel Andreas Richter John P. Burrows 《Atmospheric environment (Oxford, England : 1994)》2009,43(32):5046-5055
In this paper, the NOx emission scaling factors applied over the 2001 National Emissions Inventory (NEI) are estimated through a four-dimensional variational (4D-Var) approach using SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY) tropospheric NO2 columns measured during summer 2004. In the “top-down” approach, two-month average NO2 columns are assimilated into a regional chemical transport model (CTM), STEM, using different assimilation setups. In a basic setup, NOx emissions are adjusted by assimilating the NO2 columns. A more general setup of emission inversion allows the initial O3 concentrations be adjusted along with the NOx emissions. A final case is set up to assimilate both the NO2 columns and O3 measurement from various platforms while allowing adjustments of both the NOx emissions and the initial O3 concentrations. It is found that the addition of O3 measurements did not improve the NOx emission inversion. With the NOx emission at surface and upper levels being adjusted separately, results from four cases show that the elevated NOx emission reduction ranges from 8.9% to 11.4%, and the surface NOx emission reduction is up to 6.6%. All the cases show NOx emission reduction in Ohio valley and Washington, District of Columbia areas. 相似文献
457.
Imad El Haddad Nicolas Marchand Julien Dron Brice Temime-Roussel Etienne Quivet Henri Wortham Jean Luc Jaffrezo Christine Baduel Didier Voisin Jean Luc Besombes Gregory Gille 《Atmospheric environment (Oxford, England : 1994)》2009,43(39):6190-6198
A study to characterize primary particulate matter (PM2.5 and PM10) from the French vehicular fleet was conducted during winter 2008, in a tunnel in Marseille, France. The carbonaceous fraction represents 70% of the aerosol mass and elemental carbon fraction (EC) represent 60% of the carbonaceous fraction. The organic carbon OC was characterized in term of its water soluble fraction, functionalization rate and HULIS content. Seventy trace organic compounds including alkanes, polycyclic aromatic hydrocarbons (PAH), petroleum biomarkers and carboxylic acids were also quantified, in order to determine an organic emission profile for chemical mass balance modeling studies. Such source profiles were still missing in Europe and particularly in France. The profile obtained in this study is consistent with profiles determined in tunnel or dynamometer studies performed in other countries during the last ten years. These results suggest that organic compounds profiles from vehicular exhaust emissions are not significantly influenced by the geographic area and are thus suitable for use in aerosol source apportionment modeling applied across extensive regions. The chemical profile determined here is very similar to those obtained for diesel emissions with high concentrations of EC relative to OC (EC/OC = 1.8) and low concentrations of the higher molecular weight PAH. These results are consistent with the high proportion of diesel vehicles in the French fleet (49%). 相似文献
458.
Bruland GL Osborne TZ Reddy KR Grunwald S Newman S DeBusk WF 《Environmental monitoring and assessment》2007,129(1-3):379-395
We assessed recent changes in the distribution of soil total phosphorus (TP) in Water Conservation Area 3 (WCA-3) of the Everglades.
Soil cores were collected in 1992 and 2003 at 176 sites. To reflect hydrologic boundaries within the system, WCA-3 was divided
into three zones (3AN, 3AS, and 3B). Total P was mapped on both a mass (TPm) and a volumetric basis (TPv) to determine if
spatial distributions varied depending on the choice of units. Interpolated maps for both years showed that the highest levels
of TPm were located in 3AN and in boundary areas of all zones that received surface water inputs of P from canals. Increases
in TPm were greatest in central 3AN in an area adjacent to the Miami Canal that received inputs from a water control structure.
Interpolated maps for TPv illustrated that a hotspot present in 1992 had disappeared by 2003. The highest levels of TPv in
2003 were located in northwestern 3AN, a region of WCA-3 that has been chronically overdrained and burned in 1999. From 1992
to 2003, increases in TPm were observed for 53% of the area of WCA-3, while only 16% of WCA-3 exhibited increases in TPv.
In 1992, approximately 21% of WCA-3 had TPm concentrations in the 0–10 cm layer >500 mg kg−1, indicating P enrichment beyond historic levels. Eleven years later, 30% of the area of WCA-3 had TPm >500 mg kg−1. This indicated that during this period, the area of WCA-3 with enriched TPm concentrations increased about one % year−1. 相似文献
459.
Gregory S. Douglas Jeffery H. Hardenstine Roopa Kamath Deyuan Kong Robert E. Hoffmann Sara McMillen 《补救:环境净化治理成本、技术与工艺杂志》2020,30(4):27-37
Bioremediation is a proven alternative for remediating petroleum‐impacted soils at exploration and production (E&P) sites. Monitoring remediation performance can involve detection and quantification of biodegradation resistant compounds such as C3017α(H),21β(H)‐hopane, which requires the use of gas chromatography with mass spectrometry detection (GC/MS). Due to the remoteness of many E&P sites, this technology is not always available, and alternative methods are needed to provide reliable quantitative measurements of petroleum remediation efficiency. This study provides a detailed chemical characterization of lacustrine‐sourced crude oils and a technical basis for measuring the effectiveness of bioremediation efforts for soil impacted by those crudes. We show that the novel isoprenoid hydrocarbon botryococcane is relatively stable in lacustrine‐sourced crude oils compared with C3017α(H),21β(H)‐hopane under moderate biodegradation conditions generally observed in field samples. We have also demonstrated that, due to the stability and relatively elevated concentration of botryococcane in lacustrine oils, it can be reliably measured using the more cost‐effective and available GC/FID methodology, and thereby be used to monitor the progress of ongoing soil bioremediation activities at remote sites. 相似文献
460.
Electrical resistance heating (ERH) is a common method of remediation for volatile organic compounds in unconsolidated soils, both above and below the water table. In the past eight years, ERH has been used to successfully treat 10 or more contaminated sedimentary bedrock sites. Sedimentary bedrock treatment has recently expanded to greater depths and into karst limestone environments. This article describes the implementation issues for rock remediation and provides case studies of three sites remediated by ERH in Pennsylvania and Alabama. With proper design, the remediation of sedimentary bedrock can be completed as effectively as the remediation of overburden materials. © 2014 Wiley Periodicals, Inc. 相似文献