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991.
Eddie L. Schwertz Bradley E. Spicer Henry T. Svehlak 《Journal of the American Water Resources Association》1977,13(1):107-115
ABSTRACT: The project described in this report was undertaken by the Louisiana State Planning Office to establish the extent of backwater flooding in Louisiana in April 1975. Band 7 Landsat imagery, enlarged to a scale of 1:250,000 was used to visually identify flooded areas. Inundated areas were delineated on overlays keyed to 1:250,000 U.S. Geological Survey topographic quadrangles. Tabular data identifying acres flooded, according to land use type, were derived by merging the flood map overlays with computerized 1972 land use data. Approximately 1.12 million acres of the state were inundated by flood waters. The total acreage and land use types affected by flooding were determined within 72 hours from the time the flood areas were imaged. Flooded maps were prepared for 26 parishes. Field observations were made by Louisiana Cooperative Extension Service county agents in order to determine the accuracy of parish flood maps and flood acreage figures by land use type. Results indicated that this was a fast, accurate, and relatively inexpensive method of compiling flood data for disaster planning and postflood analysis. 相似文献
992.
993.
PROBLEM: In the United States, teenage drivers have a higher crash risk and lower observed seat belt use than other age groups. METHOD: Seat belt use was examined for teenage (16-19 years) drivers who were fatally injured in traffic crashes occurring in the United States during the years 1995-2000. Vehicle, driver, and crash factors potentially related to belt use were examined. State differences in belt use rates among fatally injured teenage drivers were related to states' observed belt use rates for all ages and other state-level variables. RESULTS: During 1995-2000, mean belt use was 36% among fatally injured teenage drivers and 23% among fatally injured teenage passengers. One of the strongest predictors of higher belt use for both drivers and passengers was whether the crash occurred in a state with a primary seat belt law. Belt use rates for 1995-2000 for fatally injured teenage drivers ranged from 20% or less in six states to more than 60% in two states. States with the highest use rates were those with strong primary belt use laws and those with high rates of observed belt use for all ages. Lower belt use among fatally injured teenage drivers was associated with increasing age; male drivers; drivers of SUVs, vans, or pickup trucks rather than cars; older vehicles; crashes occurring late at night; crashes occurring on rural roadways; single vehicle crashes; and drivers with BACs of 0.10 or higher. Teenage driver belt use declined as the number of teenage passengers increased, but increased in the presence of at least one passenger 30 years or older. IMPACT ON TRAFFIC SAFETY: It is suggested that to increase teenage belt use, states should enact strong primary belt use laws and mount highly publicized efforts to enforce these laws. Graduated driver licensing systems should incorporate strong provisions that require seat belt use by teenage drivers and passengers. 相似文献
994.
On November 13-14, 2003, a symposium on high-visibility safety belt use enforcement in Raleigh, NC: (a) celebrated the 10th anniversary of North Carolina's Click It or Ticket program; (b) documented current knowledge regarding safety belt use; (c) proposed strategies to increase use further; and (d) discussed research to support these strategies. 相似文献
995.
Anthony W. Akpan 《The Environmentalist》2004,24(1):49-55
The water quality of some tropical fresh-water bodies in Uyo (Nigeria) was investigated for two years in relation to point and non-point source city effluents and slaughter-house washings discharged into them. Streams which received city effluents and slaughter-house washings were degraded in quality with acidic water (pH =5.26±0.83 to 6.20±0.56), low oxygenation (2.46±1.30 to 3.88±0.29 mgl–1), high biochemical oxygen demand (4.96±0.66 to 8.20±0.82 mgl–1) and chemical oxygen demand (88.60±3.50 to 146.36±9.86 mgl–1) than non-effluent receiving streams. High acidity in streams is due mainly to the acidic nature of underground water which replenishes the streams. Nutrient levels were high indicating enrichment from highly fertilized farmlands and slaughter-house washings. The concentrations of most of the hydrochemical variables were significantly lower in non-effluent than effluent-receiving streams. Some of the hydrochemical variables (total alkalinity, dissolved oxygen, nitrate, phosphate and conductivity) exhibited pronounced seasonality regimes with significant correlations with rainfall indicating its influence on the chemical hydrology of the water bodies. Land use in the catchment influenced water quality through inflow of nutrients, organic and inorganic contaminants and siltation. Pollution in the impacted streams is attributed mainly to episodic events. 相似文献
996.
最近10年鄱阳湖区土地利用格局的时空变化 总被引:19,自引:3,他引:16
利用1988和1998年4月份的TM遥感数据,采用最大似然法对翻阳湖区的土地利用进行机助分类。把研究区土地利用分成7种类型:林地、灌草坡、水体、湖滩洲地、耕地、城镇用地和裸地。采用空间叠加的方法得到研究区土地利用的转移短阵。结果显示,林地、水体、城镇的面积增加,灌草坡的面积减少。1998年耕地面积比1988年面积减少11.3%,湖滩洲地面积减少42.7%。对不同高程的土地利用变化分析表明,耕地、灌草坡的面积都有所减少;城镇的面积增加,林地的面积增加明显,尤其在丘陵山区。土地利用的变化受到自然和人文因子的双重影响。水体面积增加的主要因于是降水量的增大;林地、灌草坡的变化明显受到政策等因素的影响,湖滩洲地减少的主要原因是水位的升高。 相似文献
997.
Conserving genetic diversity requires an assessment of the distribution of genetic variants in relation to patterns of land
use and environmental variation at a regional scale. This assessment requires a novel approach to integrating and analyzing
the genetic and environmental data across spatial scales. To explore the integration of genetic data with other geospatial
data sets, we developed a GIS-based approach for examining patterns of genetic diversity for several species of salamanders
in southern Appalachians. The genetic data, from allozyme surveys in the genetics literature, were integrated into a GIS database
along with related attributes including population identifications and spatial locations. Using existing geospatial data,
we classified sample locations as being either protected from anthropogenic disturbance (e.g., National Parks, Wilderness
Areas) or as unprotected (e.g., private lands, multiple-use lands in National Forests). We used multidimensional scaling of
allelic frequencies and contributions of populations to interpopulation differences in allelic richness to determine which
populations had genetic characteristics most different from other populations in the sample. Measures of genetic differentiation
were integrated into the GIS database to facilitate spatial analysis and visualization of the indices in relation to land
use. This approach was useful for both identification of populations with components of genetic variation that were not well
represented at protected sites and for identifying areas of species distributions where more genetic sampling would be necessary
to make informed management decisions. Our approach could be readily adapted for use by managers and geneticists working with
other species and types of genetic markers. 相似文献
998.
Jen‐Yang Lin Shaw L. Yu Tsu‐Chuan Lee 《Journal of the American Water Resources Association》2000,36(5):989-1001
ABSTRACT: For many years, a commonly used strategy for source water protection in Taiwan has been setting up arbitrary, fixed‐width buffer zones near sensitive waters, such as water‐supply reservoirs, and prohibiting any development in their watersheds. However, such regulations are now often viewed as infringing by the government on landowners' property rights, a situation that has led to citizen protests. This paper describes a proposed strategy that is water‐quality based and uses a quantitative zoning approach. A reservoir's watershed is divided into several zones beginning from the normal water line to the divide. Different levels of best management practices (BMPs) are required for controlling runoff pollution in different zones. The layout of the management zones is based on a number of factors such as reservoir classification, water quality conditions, and physical characteristics of the watershed. The goal of promoting such an approach is to try to balance the needs of watershed development and water quality protection. A case study using the Tapu Reservoir Watershed in Northern Taiwan as an example for illustrating the proposed zoning approach is presented. 相似文献
999.
蓟运河流域地表水质时空变化特征分析 总被引:15,自引:2,他引:13
通过对不同时段和不同监测点环境监测数据的对比分析 ,研究蓟运河干流地表水质的时空变化特征 .结果发现 ,在空间上 ,蓟运河干流自上游至下游 ,地表水质总体上表现为不断恶化的趋势 ;在时间上 ,除了 NH4-N浓度有增加的趋势外 ,其它各项监测指标的浓度 ,1998年与 1995年和 1990年相比 ,没有明显的变化 .分析影响蓟运河地表水质变化的原因主要为 :土地利用结构变化 ,如耕地面积增加和林草地面积减少 ;城镇集中区大量工业废水和生活污水的排放 . 相似文献
1000.
Christopher P. Holt Paul S. Phillips Margaret P. Bates 《Resources, Conservation and Recycling》2000,30(4)
As a result of the UK Government's waste policy, which increasingly encourages sustainable development, and the realisation that water in the UK cannot be treated as an unlimited resource, there is growing interest in reducing the demand for water by industry. A series of industrial waste minimisation clubs have been set up within the country. This paper identifies the effectiveness of these clubs in reducing the demand for water. An overview of some of the clubs show how there is a major discrepancy between potential and implemented water savings, whilst a more detailed analysis of three specific examples show how water demand and cost to the company can be reduced, with the project paying for itself within around 1 year. It appears that companies are able to reduce water consumption by approximately 30%. If this level of saving was taken up by the entire industrial sector in England and Wales, water consumption could be reduced by approximately 1500 Ml/day. This reduction would be more significant in regions of lower rainfall, for example East Anglia and Southeast England. 相似文献