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441.
Marc Soutter Maria Alexandrescu Colin Schenk Radu Drobot 《Environmental science and pollution research international》2009,16(1):33-41
Background, aim, and scope
The need for global and integrated approaches to water resources management, both from the quantitative and the qualitative point of view, has long been recognized. Water quality management is a major issue for sustainable development and a mandatory task with respect to the implementation of the European Water Framework Directive as well as the Swiss legislation. However, data modelling to develop relational databases and subsequent geographic information system (GIS)-based water management instruments are a rather recent and not that widespread trend. The publication of overall guidelines for data modelling along with the EU Water Framework Directive is an important milestone in this area. Improving overall water quality requires better and more easily accessible data, but also the possibility to link data to simulation models. Models are to be used to derive indicators that will in turn support decision-making processes. For this whole chain to become effective at a river basin scale, all its components have to become part of the current daily practice of the local water administration. Any system, tool, or instrument that is not designed to meet, first of all, the fundamental needs of its primary end-users has almost no chance to be successful in the longer term.Materials and methods
Although based on a pre-existing water resources management system developed in Switzerland, the methodological approach applied to develop a GIS-based water quality management system adapted to the Romanian context followed a set of well-defined steps: the first and very important step is the assessment of needs (on the basis of a careful analysis of the various activities and missions of the water administration and other relevant stakeholders in water management related issues). On that basis, a conceptual data model (CDM) can be developed, to be later on turned into a physical database. Finally, the specifically requested additional functionalities (i.e. functionalities not provided by classical commercial GIS software), also identified during the assessment of needs, are developed. This methodology was applied, on an experimental basin, in the Ialomita River basin.Results
The results obtained from this action-research project consist of a set of tangible elements, among which (1) a conceptual data model adapted to the Romanian specificities regarding water resources management (needs, data availability, etc.), (2) a related spatial relational database (objects and attributes in tables, links, etc.), that can be used to store the data collected, among others, by the water administration, and later on exploited with geographical information systems, (3) a toolbar (in the ESRI environment) offering the requested data processing and visualizing functionalities. Lessons learned from this whole process can be considered as additional, although less tangible, results.Discussion
The applied methodology is fairly classical and did not come up with revolutionary results. Actually, the interesting aspects of this work are, on the one hand, and obviously, the fact that it produced tools matching the needs of the local (if not national) water administration (i.e. with a good chance of being effectively used in the day-to-day practice), and, on the other hand, the adaptations and adjustments that were needed both at the staff level and in technical terms.Conclusions
This research showed that a GIS-based water management system needs to be backed by some basic data management tools that form the necessary support upon which a GIS can be deployed. The main lesson gained is that technology transfer has to pay much attention to the differences in existing situations and backgrounds in general, and therefore must be able to show much flexibility. The fact that the original objectives could be adapted to meet the real needs of the local end-users is considered as a major aspect in achieving a successful adaptation and development of water resources management tools. Time needed to setup things in real life was probably the most underestimated aspect in this technology transfer process.Recommendations and perspectives
The whole material produced (conceptual data model, database and GIS tools) was disseminated among all river basin authorities in Romania on the behalf of the national water administration (ANAR). The fact that further developments, for example, to address water quantity issues more precisely, as envisaged by ANAR, can be seen as an indication that this project succeeded in providing an appropriate input to improve water quality in Romania on the long term.442.
通过采用ACE装置与烟气NOx分析仪器联用的实验室评价方法,可在更接近实际催化裂化反应-再生过程的条件下,评价助剂对再生烟气中NOx的催化转化性能,同时还可考察助剂的加入对催化裂化产品分布的影响。采用该方法对几种降NOx助剂的性能进行了评价,结果表明,在催化剂体系中含有Pt基CO助燃剂的情况下,加入4%的RDNO;助剂后,烟气NOx降低幅度约30%~40%,且催化裂化产品分布基本不受影响。 相似文献
443.
Yongxiang Han Xiaomin Fang Tianliang Zhao Huzhi Bai Shichang Kang Lianchun Song 《Atmospheric environment (Oxford, England : 1994)》2009,43(3):568-574
Dust aerosols play an important role in modulating the hydrologic cycle. The Tibetan Plateau (TP) is little polluted by human activities as an ideal site to study the effect of dust aerosol on precipitation. In this study, observational data of dust storms and precipitation in the TP and its vicinities as well as CALIPSO satellite data were used to analyze the distributions and vertical structure of dust storms on the plateau. The results showed that dust storms occur with high frequency and raise dust particles into the troposphere from ground level to a height of 5–9 km to modulate the hydrologic cycle in the TP. There are significant negative correlations between dust aerosol and precipitation in the dust source regions during the period of both 40 and 200 years. It is found that the role of precipitation in suppressing dust storms could be unimportant, while dust aerosol may play an important role in suppressing precipitation in the hinterland of the TP. Our study provides a potential approach to better understand the climate changes in the TP. 相似文献
444.
Zhi-Ping Wang Yang Song Jay Gulledge Qiang Yu Hong-Sheng Liu Xing-Guo Han 《Atmospheric environment (Oxford, England : 1994)》2009,43(13):2148-2153
A budget for the methane (CH4) cycle in the Xilin River basin of Inner Mongolia is presented. The annual CH4 budget in this region depends primarily on the sum of atmospheric CH4 uptake by upland soils, emission from small wetlands, and emission from grazing ruminants (sheep, goats, and cattle). Flux rates for these processes were averaged over multiple years with differing summer rainfall. Although uplands constitute the vast majority of land area, they consume much less CH4 per unit area than is emitted by wetlands and ruminants. Atmospheric CH4 uptake by upland soils was ?3.3 and ?4.8 kg CH4 ha?1 y?1 in grazed and ungrazed areas, respectively. Average CH4 emission was 791.0 kg CH4 ha?1 y?1 from wetlands and 8.6 kg CH4 ha?1 y?1 from ruminants. The basin area-weighted average of all three processes was 6.8 kg CH4 ha?1 y?1, indicating that ruminant production has converted this basin to a net source of atmospheric CH4. The total CH4 emission from the Xilin River basin was 7.29 Gg CH4 y?1. The current grazing intensity is about eightfold higher than that which would result in a net zero CH4 flux. Since grazing intensity has increased throughout western China, it is likely that ruminant production has converted China's grazed temperate grasslands to a net source of atmospheric CH4 overall. 相似文献
445.
There are two principal strategies for managing climate change risks: mitigation and adaptation. Until recently, mitigation
and adaptation have been considered separately in both climate change science and policy. Mitigation has been treated as an
issue for developed countries, which hold the greatest responsibility for climate change, while adaptation is seen as a priority
for the South, where mitigative capacity is low and vulnerability is high. This conceptual divide has hindered progress against
the achievement of the fundamental sustainable development challenges of climate change. Recent attention to exploring the
synergies between mitigation and adaptation suggests that an integrated approach could go some way to bridging the gap between
the development and adaptation priorities of the South and the need to achieve global engagement in mitigation. These issues
are explored through a case study analysis of climate change policy and practice in Bangladesh. Using the example of waste-to-compost
projects, a mitigation-adaptation-development nexus is demonstrated, as projects contribute to mitigation through reducing
methane emissions; adaptation through soil improvement in drought-prone areas; and sustainable development, because poverty
is exacerbated when climate change reduces the flows of ecosystem services. Further, linking adaptation to mitigation makes
mitigation action more relevant to policymakers in Bangladesh, increasing engagement in the international climate change agenda
in preparation for a post-Kyoto global strategy. This case study strengthens the argument that while combining mitigation
and adaptation is not a magic bullet for climate policy, synergies, particularly at the project level, can contribute to the
sustainable development goals of climate change and are worth exploring. 相似文献
446.
The fate and transport processes of a toxic chemical such as atrazine, an herbicide, in a reservoir are significantly influenced
by hydrodynamic regimes of the reservoir. The two-dimensional (2D) laterally-integrated hydrodynamics and mass transport model,
CE-QUAL-W2, was enhanced by incorporating a submodel for toxic contaminants and applied to Saylorville Reservoir, Iowa. The
submodel describes the physical, chemical, and biological processes and predicts unsteady vertical and longitudinal distributions
of a toxic chemical. The simulation results from the enhanced 2D reservoir model were validated by measured temperatures and
atrazine concentrations in the reservoir. Although a strong thermal stratification was not identified from both observed and
predicted water temperatures, the spatial variation of atrazine concentrations was largely affected by seasonal flow circulation
patterns in the reservoir. In particular, the results showed the effect of flow circulation on spatial distribution of atrazine
during summer months as the river flow formed an underflow within the reservoir and resulted in greater concentrations near
the surface of the reservoir. Atrazine concentrations in the reservoir peaked around the end of May and early June. A good
agreement between predicted and observed times and magnitudes of peak concentrations was obtained. The use of time-variable
decay rates of atrazine led to more accurate prediction of atrazine concentrations, while the use of a constant half-life
(60 days) over the entire period resulted in a 40% overestimation of peak concentrations. The results provide a better understanding
of the fate and transport of atrazine in the reservoir and information useful in the development of reservoir operation strategies
with respect to timing, amount, and depth of withdrawal. 相似文献
447.
Understanding how setting attributes influence the nature of the visitor experience is crucial to effective recreation management.
Highly influential attributes are useful indicators to monitor within a planning framework, such as Limits of Acceptable Change.
This study sought to identify the setting attributes perceived to have the most profound effect on the ability to have “a
real wilderness experience” and to assess the degree to which attribute importance varied with situational context and visitor
characteristics. To this end, exiting hikers were surveyed at moderate and very high use trailheads in Alpine Lakes Wilderness,
WA (USA), and Three Sisters Wilderness, OR (USA). They were asked about the degree to which encountering varying levels of
different setting attributes would add to or detract from their experience. Attributes with the largest range of effect on
experience, based on evaluations of different levels, were considered most important. The most influential attributes were
litter and several types of campsite interaction—people walking through camp and number of other groups camping close by.
The perceived importance of setting attributes did not vary much between wilderness locations with substantially different
use levels, suggesting that conclusions are robust and generalizable across wilderness areas. There also was little difference
in the perceptions of day and overnight visitors. In contrast, we found substantial variation in the perceived importance
of setting attributes with variation in wilderness experience, knowledge, attachment, and motivation. Our results validate
the emphasis of many wilderness management plans on indicators of social interaction, such as number of encounters. 相似文献
448.
The Effect of Water Harvesting Techniques on Runoff,Sedimentation, and Soil Properties 总被引:1,自引:0,他引:1
This study addressed the hydrological processes of runoff and sedimentation, soil moisture content, and properties under the
effect of different water harvesting techniques (treatments). The study was conducted at three sites, representing environmental
condition gradients, located in the southern part of the West Bank. For each treatment, the study evaluated soil chemical
and physical properties, soil moisture at 30 cm depth, surface runoff and sedimentation at each site. Results showed that
runoff is reduced by 65–85% and sedimentation by 58–69% in stone terraces and semi-circle bunds compared to the control at
the semi-humid site. In addition, stone terraces and contour ridges significantly reduced the amount of total runoff by 80%
and 73%, respectively, at the arid site. Soil moisture content was significantly increased by water harvesting techniques
compared to the control in all treatments at the three study sites. In addition, the difference between the control and the
water harvesting structures were higher in the arid and semi-arid areas than in the semi-humid area. Soil and water conservation,
via utilization of water harvesting structures, is an effective principle for reducing the negative impact of high runoff
intensity and subsequently increasing soil moisture storage from rainfall. Jessour systems in the valley and stone terraces
were effective in increasing soil moisture storage, prolonging the growing season for natural vegetation, and decreasing the
amount of supplemental irrigation required for growing fruit trees. 相似文献
449.
Diversity of Soil Nematodes in Areas Polluted with Heavy Metals and Polycyclic Aromatic Hydrocarbons (PAHs) in Lanzhou,China 总被引:1,自引:0,他引:1
This study investigated the soil nematode community structure along the Yellow River in the Lanzhou area of China, and analyzed
the impact of heavy metals (Cd, Pb, Cr, Cu, and Zn) and polycyclic aromatic hydrocarbons (PAHs) on the nematode community.
Soil samples from five locations (named A–E), which were chosen for soil analysis, showed significant differences in their
heavy metal content (p < 0.01), as well as in the variety of nematodes (up to 41 genera) and families (up to 20) that were present. The different
samples also differed significantly in the total PAH content (p < 0.05), as well as the six types of PAH present. Sites A–C showed the most severe contamination with heavy metals and PAHs;
these sites had the lowest abundance of fungivores and omnivore/predators, but the proportion of bacteriovores was the highest
(p < 0.05). Site E, in contrast, showed only minor pollution with heavy metals and PAHs, and it contained the highest abundance
of plant parasites (p < 0.05). Several nematode ecological indicators were found to correlate with concentration of soil pollutants at all the
sites tested: the maturity index (MI, in addition to plant parasites), plant parasite index (PPI), ΣMI (including all the
soil nematodes), Shannon-Wiener diversity index (H′′), and Wasilewska index (WI). Disturbance to the soil environment was more severe when MI, ΣMI, and H′ values were lower. The results of the study show that the abundance and structure of the soil nematode communities in the
sampling locations were strongly influenced by levels of heavy metals and PAHs in the soil. They also show that the diversity
index H′ and the maturity index can be valuable tools for assessing the impact of pollutants on nematodes. 相似文献
450.
Frank Merry Britaldo Soares-Filho Daniel Nepstad Gregory Amacher Hermann Rodrigues 《Environmental management》2009,44(3):395-407
Logging has been a much maligned feature of frontier development in the Amazon. Most discussions ignore the fact that logging
can be part of a renewable, environmentally benign, and broadly equitable economic activity in these remote places. We estimate
there to be some 4.5 ± 1.35 billion m3 of commercial timber volume in the Brazilian Amazon today, of which 1.2 billion m3 is currently profitable to harvest, with a total potential stumpage value of $15.4 billion. A successful forest sector in
the Brazilian Amazon will integrate timber harvesting on private lands and on unprotected and unsettled government lands with
timber concessions on public lands. If a legal, productive, timber industry can be established outside of protected areas,
it will deliver environmental benefits in synergy with those provided by the region’s network of protected areas, the latter
of which we estimate to have an opportunity cost from lost timber revenues of $2.3 billion over 30 years. Indeed, on all land
accessible to harvesting, the timber industry could produce an average of more than 16 million m3 per year over a 30-year harvest cycle—entirely outside of current protected areas—providing $4.8 billion in returns to landowners
and generating $1.8 billion in sawnwood sales tax revenue. This level of harvest could be profitably complemented with an
additional 10% from logging concessions on National Forests. This advance, however, should be realized only through widespread
adoption of reduced impact logging techniques. 相似文献