共查询到13条相似文献,搜索用时 62 毫秒
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瓦埠湖位于淮河中游南岸,流经寿县、合肥市及淮南市,是安徽省五大淡水湖之一,南通大别山水源,承接江淮分水岭以北来水,下游与淮河相连。该湖流域面积4096平方公里,南北长60公里,水面最宽处6公里,正常水位18米,蓄水面积156平方公里,湖底高程15.5米,相应容积为2.2亿立方米。 相似文献
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Bruce K. Ferguson 《Journal of environmental management》1996,48(4):387-395
Land use design that recognizes the landscape attributes that characterize homeostatic health can emphasize them during land use change. The attributes of landscape health are the working mechanisms of all open systems, and can be observed in the homeostatic behavior of forests, deserts and floodplains. These attributes are openness, self-regulation, storage and diversity. The attributes of health comprise criteria for evaluating and guiding land use. To maintain landscape health, land use design can maintain and restore these mechanisms during change of moderate pace and scale. 相似文献
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早听说阿寒国立公园是日本北海道最美丽的公园之一,初春时节我来到风光秀丽的阿寒湖游览时,这片胜地让我好好地静心徜徉了一回。 相似文献
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It is characteristic to be in the midst of change and not to recognize it. In retrospect 1970–72 at Clark University presaged a successful universalization of environmental perception, but it was a high point rather than a beginning in pursuit of the higher aspirations of the then-fledgling field. These aspirations—to solve practical problems, to develop a common methodology, to bridge the disciplines, and to develop or revise a theory—have never been fully realized. Widely accepted today, environmental perception and behavior mirrors the everyday differences within and between disciplines and thus is divided by theoretical ideology, substantive focus and views as to what constitutes data. As with the individual disciplines, I have successfully integrated environmental perception into my own work, moving it from the exceptional to the everyday, and with some regret, from the magic of 1970–72 to the science of today. 相似文献
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渤海西部局地大雾变化趋势及成因分析 总被引:1,自引:0,他引:1
利用2002-2012年秦皇岛地区4个气象站大雾监测及Micaps 3.0常规资料,对比分析卢龙与沿海站大雾的时空尺度分布特征,对大雾持续时间、日数进行跨月、跨年统计,从中筛选出189个样本个例进行变化趋势分析。对典型17个过程个例按能见度大小进行3级设定,对应其同步天气背景,分析大雾偏多的成因。 相似文献
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Hearne RR 《Environmental management》2007,40(6):842-852
Institutions are the rules and norms that guide societal behavior. As societies evolve—with more diverse economies, increased
populations and incomes, and more water scarcity—new and more complex water management institutions need to be developed.
This evolution of water management institutions may also be observed across different constituencies, with different societal
needs, in the same time period. The Red River of the North basin is particularly well suited for research on water management
issues. A key feature of water management in the Red River Basin is the presence of three completely different sets of water
law. Minnesota’s water law is based upon riparian rights. North Dakota’s water law is based upon prior appropriation. Manitoba
has a system of water allocation that features provincial control. Because the basin is fairly homogeneous in terms of land
use and geographic features, its institutional diversity makes this an excellent case study for the analysis of local water
institutions. This article reviews the local water management institutions in the Red River Basin and assesses the ongoing
institutional evolution of local water management. 相似文献
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Karen A. Blocksom Bradley C. Autrey Margaret Passmore Lou Reynolds 《Journal of the American Water Resources Association》2008,44(3):577-593
Abstract: In 2003, we compared two benthic macroinvertebrate sampling methods that are used for rapid biological assessment of wadeable streams. A single habitat method using kick sampling in riffles and runs was compared to a multiple habitat method that sampled all available habitats in proportion of occurrence. Both methods were performed side‐by‐side at 41 sites in lower gradient streams of the Piedmont and Northern Piedmont ecoregions of the United States, where riffle habitat is less abundant. Differences in sampling methods were examined using similarity indices, two multimetric indices [the family‐level Virginia Stream Condition Index (VSCI) and the species‐level Macroinvertebrate Biotic Integrity Index (MBII)], their component metrics, and bioassessment endpoints based on each index. Index scores were highly correlated between single and multiple habitat field methods, and sampling method comparability, based on comparison of similarities between and within sampling methods, was particularly high for species level data. The VSCI scores and values of most of its component metrics were not significantly higher for one particular method, but relationships between single and multiple habitat values were highly variable for percent Ephemeroptera, percent chironomids, and percent Plecoptera and Trichoptera (Hydropsychidae excluded). A similar level of variability in the relationship was observed for the MBII and most of its metrics, but Ephemeroptera richness, percent individuals in the dominant five taxa, and Hilsenhoff Biotic Index scores all exhibited differences in values between single and multiple habitat field methods. When applied to multiple habitat samples, the MBII exhibited greater precision, higher index scores, and higher assessment categories than when applied to single habitat samples at the same sites. In streams with limited or no riffle habitats, the multiple habitat method should provide an adequate sample for biological assessment, and at sites with abundant riffle habitat, little difference would be expected between the single and multiple habitat field methods. Thus, in geographic areas with a wide variety of stream types, the multiple habitat method may be more desirable. Even so, the variability in the relationship between single and multiple habitat methods indicates that the data are not interchangeable, and we suggest that any change in sampling method should be accompanied by a recalibration of any existing assessment tool (e.g., multimetric index) with data collected using the new method, regardless of taxonomic level. 相似文献