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991.
Lee H. MacDonald 《Journal of the American Water Resources Association》1993,29(3):357-368
ABSTRACT: Recent assessments have emphasized the lack of a field and laboratory component in hydrologic education at the university level. Consequences of this lack include: (1) an unwarranted faith in published data; (2) lack of appreciation for the spatial and temporal variability of most hydrologic processes; (3) lack of appreciation for the difficulty of collecting good quality field data; (4) an inability to design and execute projects to collect field data; (5) a lack of field experience which can be applied when confronted with different problems or new environments; (6) an inability to evaluate published materials or models against “field reality;” (7) an excessive reliance on, and trust in, theoretical or conceptual models; and (8) reduced potential for lifelong learning through observation and analysis. Field courses need not be costly or difficult, but the instructor must be willing to adapt to the uncertainty and problems associated with field measurements. A recently updated course on watershed measurements at Colorado State University illustrates the type of field courses which can be developed if there is the necessary commitment and flexibility. The lack of a current text can be overcome by assembling selected portions of existing government documents, and a sample bibliography is included. 相似文献
992.
F. Harvey Dove Peter J. Schreuder 《Journal of the American Water Resources Association》1979,15(2):326-336
ABSTRACT: A visual selection technique can be utilized to locate potential well field sites prior to on-site testing. The technique is based upon an understanding of the regional hydrology and an appreciation for development goals such as the identification of high-yield and low-impact locations. Although the uniqueness of Pasco, Pinellas, and Hillsborough Counties in Western Florida has been incorporated into the current application, the methodology, with modifications, is transferable to other geographic regions. Overlays of each criterion used in site selection are combined to form a regional composite showing favorable site locations and further serve a useful communications role as visual aids during public presentation. Implications of direct and indirect cost savings to the public are obtained when the methodology is applied to the location of municipal well fields. 相似文献
993.
Jay R. Stauffer Kenneth L. Dickson John Cairns 《Journal of the American Water Resources Association》1974,10(5):860-876
ABSTRACT. Studies were conducted to determine the distribution of fish in the New and East Rivers in relation to thermal discharges from Appalachian Power Company's fossil fuel plant at Glen Lyn, Virginia. Over 15,300 specimens representing 41 species were collected with seines, electrogear and rotenone at six sampling locations from February, 1973 to October 1973. Sampling frequency was designed to evaluate the effects of ambient temperature upon preferred temperature. Diversity indices were calculated for each location. There was a slight decrease in the diversity indices for those stations located in the thermal discharge. Condition coefficients calculated for Notropis albeolus Jordan, Notropis rubellus Aqasaiz, Notropis spilopterus Cope, Ictalurus punctatus Rafinesque, and Etheostoma blennioides Rafuesque were found to be significantly (p =.05) lower in the thermal discharge for all species tested except E. blennioides. Temperatures were plotted against frequency of capture to determine a particular species temperature selection from field data and indicated that: (1) Some species avoided high temperatures (i.e., Curnpostoma anomalum Rafuesque). (2) Some species were attracted to high temperatures (i.e., Ictalurus punctatus). (3) Some species distribution was not effected by temperatures (i.e., Notropis spilopterus). 相似文献
994.
煤炭企业清洁生产的中/高费方案评述 总被引:1,自引:0,他引:1
简述了煤炭企业在清洁生产审核过程中如何产生中/高费方案,分析了中/高费方案所占的比例。通过3个工程实例的分析证明,中/高费方案的实施给煤炭企业带来良好的环境效益和经济效益。 相似文献
995.
J. A. Carfrae L. J. Sheppard J. A. Raven I. D. Leith W. Stein A. Crossley M. Theobald 《Water, Air, & Soil Pollution: Focus》2004,4(6):229-239
This paper reports data from a field study investigating the impacts of elevated ammonia (NH3) deposition on Calluna vulgaris growing on an ombrotrophic peat bog in S.E. Scotland. Shoot extension, foliar N concentrations, chlorophyll concentration and chlorophyll fluorescence were measured during the second growing season of exposure to a gradient of ammonia concentrations. Results indicate that NH3 increases growth between 150–200 kg N ha–1y–1 cumulative deposition. Foliar N content increased significantly in response to NH3 cumulative deposition up to 400 kg N ha–1 y–1 whereas chlorophyll a content significantly decreased. Measurements of Fv/Fm suggest that although NH3 exposure altered the growth and reduced chlorophyll a, the efficiency of photosystem II was insensitive to NH3-N deposition at this stage. 相似文献
996.
997.
998.
城市地下水流场人工调控与减灾方案 总被引:2,自引:1,他引:1
以郑州市为例,针对城市区域长期过量开采地下水导致的一系列严重的环境地质灾害,诸如地下水水位持续下降形成区域地下水降落漏斗并不断扩张、含水层疏干、供水井吊泵、泉水断流、地下建筑工程浸没、地面沉降和塌陷等,探讨了城市地下水流场人工调控的减灾方案。建立了地下水系统的准三维动态数值仿真模型,以非均质各向同性渗流模型仿真地下水流,用不规则三角网格有限差分法求解了三维数值仿真模型。先解逆问题反求参数,再解正问题计算地下水各项资源量,数值仿真预报地下水渗流场至1998年。在此基础上,通过地下水渗流场的宏观调控与优化管理,使研究区内不合理开采地下水资源所引发的环境灾害减小到最低程度,为郑州市的环境减灾工作提供了科学依据。 相似文献
999.
聚氯乙烯生产中副产高沸物的综合利用 总被引:5,自引:0,他引:5
介绍了以PVC生产中副产的高沸物精制后作溶剂,降解后的废聚苯乙烯泡沫塑料的作主料,制造塑化防腐漆的工艺流程,产品性能及经济效益。 相似文献
1000.
V890B是英国LDS公司最大推力的风冷振动台,本文就V890B振动台涉及的主要专利技术和特征进行分析叙述,供试验同行参考了解。 相似文献