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231.
Donald Rundquist Gene Murray Lloyd Queen 《Journal of the American Water Resources Association》1985,21(6):989-994
The Sandhills region represents a tremendous water resource for the State of Nebraska. Small shallow lakes, marshes, and subirrigated meadows are abundant due to interactions between ground water and surface water. One theory relating ground water to lake-flow systems in the Sandhills has been termed the “flow-through” concept. Thermal-infrared remotely acquired images document the flow-through model for a test site in Western Nebraska. 相似文献
232.
Graham Hadley 《Journal of Environmental Planning and Management》1984,27(1):34-38
Enterprise Zones have been in operation as part of government policy for over three years. They contain a special form of planning procedures whereby a general planning permission is given for development subject to certain exclusions and conditions. This article summarises and compares the planning schemes operating in all 25 Enterprise Zones in Britain and considers what have been the results of this planning approach to date in the zones. The operation of these planning schemes has not led to a feared lowering of development standards but nevertheless is not regarded as being suitable for wider application in the planning system. 相似文献
233.
John D. Hewlett James C. Fortson 《Journal of the American Water Resources Association》1982,18(6):983-988
ABSTRACT: A paired watershed experiment on the southeastern Piedmont to determine the effect of clearcutting loblolly pine on water quantity, quality, and timing has shown that stream water temperatures we increased as much as 20°F even though a partial buffer strip of trees and shrubs were left in place to shade the stream. Water time minimum stream temperatures were lowered as much as 10°F by the same treatment. A stream temperature model now in use did not predict such elevated temperatures. The authors suggest that forest cover reductions in areas of gentle land relief may elevate the temperature of shallow ground water moving to the stream, even with a substantial buffer strip Ln place. 相似文献
234.
本文根据中国光温生态试验资料及四川水稻品比试验与气象观测的历史资料,讨论了早、中稻感温性和对温度的适应性,分析了播期、纬度、海拔等因素与稻种需求积温量的关系,以水稻品种类型对热量的适应性指标为依据,考虑四川水稻气候生态的差异性,划分出水稻综合气候生态类型区。 相似文献
235.
Williams GM Pickup RW Thornton SF Lerner DN Mallinson HE Moore Y White C 《Journal of contaminant hydrology》2001,53(3-4):175-197
The distillation of acidified coal tars for up to 50 years has given rise to a phenol plume approximately 500 m long, 50 m deep and containing up to 15 g l(-1) dissolved organic carbon (DOC) in the Triassic Sandstones aquifer. A conceptual biogeochemical model based on chemical and microbiological analysis of groundwater samples has been developed as a preliminary to more detailed studies of the controls on natural attenuation. While the development of redox zones and the production of methane and carbon dioxide provide evidence of natural attenuation, it appears that degradation is slow. The existence of sulphate in the plume indicates that this electron acceptor has not been depleted and that consequently methanogenesis is probably limited. Based on a simple estimate of sulphate input concentration, a half-life of about 15 years has been estimated for sulphate reduction. Geochemical modelling predicts that increased alkalinity within the plume has not led to carbonate precipitation, and thus within the limits of accuracy of the measurement, alkalinity may reflect the degree of biodegradation. This implies a loss of around 18% of the DOC over a 30-year period. Despite limited degradation, microbial studies show that there are diverse microbial communities in the aquifer with the potential for both anaerobic and aerobic biodegradation. Microbial activity was found to be greatest at the leading edge of the plume where DOC concentrations are 60 mg l(-1) or less, but activity could still be observed in more contaminated samples even though cells could not be cultured. The study suggests that degradation may be limited by the high phenol concentrations within the core of the plume, but that once diluted by dispersion, natural attenuation may proceed. More detailed studies to confirm these initial findings are identified and form the basis of associated papers. 相似文献
236.
Xi Chen Xunhong Chen Clinton Rowe Qi Hu Mark Anderson 《Journal of the American Water Resources Association》2003,39(1):217-228
ABSTRACT: This paper presents hydrological characteristics of the streamflow of the Dismal, Middle Loup, North Loup, and Cedar Rivers in the Nebraska Sand Hills and their relation to climate and ground water variation. Time series of streamflow, precipitation, temperature, and ground water levels from 1976 to 1998 were used to analyze trends and fluctuations of streamflow and to determine relationships among streamflow, climate, and the ground water system. An increase of precipitation and a decrease of maximum temperature over the period resulted in higher ground water levels and increased streamflow in the region. The high permeability of the soil and the thick unsaturated zone enhance precipitation recharge, limit surface runoff, and prevent ground water losses through evapotranspiration. Thus, an abundance of ground water is stored, supplying more than 86 percent of streamflow in the four rivers. Streamflow is generally more constant in the Sand Hills than elsewhere in the region. The four rivers present different hydrologic characteristics because of the spatial heterogeneity in hydrogeologic conditions. Streamflow of the Dismal and Middle Rivers, which are less sensitive to climatic variation, is much steadier than that of the North Loup and Cedar Rivers. 相似文献
237.
238.
我国城镇可持续发展实验区建设的理论与实践 总被引:1,自引:0,他引:1
迟计 《中国人口.资源与环境》1999,9(4):27-31
可持续发展综合实验区是我国实施可持续发展战略的重要行动。本文在分析、总结我国城镇可持续发展实验区实践的基础上,提出了建设城镇可持续发展实验区的基本思路 相似文献
239.
“十二五”时期,我国环境服务业将迎来大发展.在这一背景下环境服务业发展的重要模式和载体一服务业集聚区的建设在我国刚刚起步.本文在借鉴环境规划、服务业集聚区规划编制方法的基础上,提出了环境服务业集聚区的规划方法和步骤,并对优势分析、功能定位、主导产业、建设目标、建设思路等八个规划关键性问题进行了分析.以环境保护部批准试点建设的第一个环境服务业集聚区—华南环境服务业集聚区建设规划为例,详细探讨了上述规划方法在该案例中的具体应用,以期为环境服务业集聚区规划方法的研究提供借鉴. 相似文献
240.