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251.
A field study was conducted to assess variations in physico-chemical characteristics of water of the springs located within
the boundary of a Central Himalayan town where the springwater is used for drinking purposes. Monitoring of 12 springs was
carried out for three seasons (winter, summer and monsoon). The results indicate direct influence of unplanned sewage disposal
on the springwater quality as reflected by significant regional variations in the concentration of nitrates, chlorides, sulfates,
sulfides and electrical conductivity. Population density varies within the town from 3110 to 14 137 persons/km–2 and has direct relationship with water quality. Springs located in the densely populated area had higher concentrations of
all these compounds. Concentrations of nitrates up to 60 ppm were observed in some springs, making water unsuitable for human
consumption. No significant changes were observed in springwater quality during different seasons.
Received: 3 February 1995 · Accepted: 27 February 1996 相似文献
252.
253.
《The Professional geographer》1983,35(4):488-524
Book Reviewed in this article: Main Street: Northeastern Oregon: The Founding and Development of Small Towns . Barbara Ruth Bailey . Food Politics: The Regional Conflict . David N. Balaam and Michael J. Carey , eds. The International Economy and Industrial Development: Trade and Investment in the Third World . R. Ballance , J. Ansari and H. Singer . Neighborhoods in Urban America . Ronald H. Bayor , ed. The English Heartland . By Robert Beckinsale and Monica Beckinsale . Regional Dimensions of Industrial Policy . Michael E. Bell and Paul S. Lande , eds. Tension Areas of the World . D. Gordon Bennett , ed. Latin America: an Introductory Survey . B. W. Blouet and O. M. Blouet , eds. Integration and Division: Geographical Perspectives on the Northern Ireland Problem . Frederick W. Boal and J. Neville H. Douglas , eds. Energy and Land Use . Robert W. Burchell and David Listokin , eds. Slopes and Weathering . Michael Clarke and John Small . Alaska's Rural Development . Peter G. Cornwall and Gerald Mc Beath , eds. The Politics of Park Design: A History of Urban Parks in America . Galen Cranz . World Congress on Land Policy, 1980, Proceedings . Matthew Cullen and Sharon Woolery , eds. Oregon Divided: A Regional Geography . Samuel N. Dicken and Emily F. Dicken . Urban Food Marketing and Third World Rural Development . T. Scarlett Epstein . South Africa: Spatial Frameworks for Development . T. J. D. Fair . Institutions and Geographical Patterns . Robin Flowerdew , ed. Industrialization of U.S. Agriculture, An Interpretive Atlas . Howard F. Gregor . Planning Theory: Prospects for the 1980s . Patsy Healy , Glen Mc Dougall and Michael J. Thomas , eds. Neighborhood Mobilization: Redevelopment and Response . Jeffrey R. Henig . The American Urban System: A Geographical Perspective . R. J. Johnston . Climate, History and the Modern World . Hubert H. Lamb . Climate and History: Studies in Past Climates and Their Impact on Man . T. M. L. Wigley , M. J. Ingram and G. Farmer . China: Railways and Agricultural Development, 1875–1935 . Ernest P. Liang . A Desirable Energy Future—A National Perspective . Robert S. Livingston , T. D. Anderson , T. M. Besmann , M. Olszewski , A. M. Perry , and C. D. West . Topothesia: Essays Presented to T. S. Ó Máille . B. S. Mac Aodha , ed. Transportation for the Poor: Research in Rural Mobility . Hal S. Maggied . Land Uses in American Cities . Harold M. Mayer and Charles R. Haves . Industrial Organisation and Location . Philip Mc Dermott and Michael Taylor . Human Adaptability: an Introduction to Ecological Anthropology . Emilio F. Moran . Regional Analysis and the New International Division of Labor . Frank Moulaert and Patricia W. Salinas , eds. The Nuclear War Atlas. Victoriaville, Quebec, Canada : Urbanization and Environmental Quality . Isao Orishimo . The Garden of Eden: The Botanic Garden and the Re-Creation of Paradise . John Prest . Earthfire, The Eruption of Mount St. Helens . Charles Rosenfeld and Robert Cooke . Contest for the South China Sea . Marwyn S. Samuels . The Future of the Wetlands: Assessing Visual-Cultural Values . Richard C. Smardon , ed. Tucson: the Life and Times of An American City. C. L. Sonnichsen . The Geography of Multinationals . Michael Taylor and Nigel Thrift , eds. Impact of Marine Pollution on Society . Virginia Tippie and Dana Kester . Reviving the Industrial City: the Politics of Urban Renewal in Lyon and Birmingham . Jerry A. Webman . Andean Reflections: Letters from Carl O. Sauer While on a South American Trip under a Grant from the Rockefeller Foundation, 1942 . Robert C. West , ed. Cartographic Drawing with Computers . P. Yoeli . 相似文献
254.
Study on urban construction planning based on karst landscape protection contributes to sustainable development of urban construction in karst area. Jinan is a city famous for karst spring water. Karst landscape plays a decisive role in urban construction. Through hydrogeological analysis, the distribution characteristics of karst mountain, cave, gully and flat dam in Jinan are analyzed. It is revealed that various karst landforms are involved in the spring circulation process to varying degrees. Some karst landforms have been destroyed in the process of urban construction and the karst landscape has been overexploited resulting in the direct or indirect weakening of spring water recharge and infiltration capacity and the decrease of spring water flow. Through the study of the principle of organic combination of karst landscape and urban construction planning, on the basis of protecting the ecological environment of the south, paying attention to the overall protection of the karst geomorphology system and the principle of accessibility of the karst landscape, the development countermeasures guided by urban planning are put forward based on karst landforms protection. On the basis of fully considering the special karst landform conditions in Jinan, the countermeasures are that the ecological control red line of urban construction planning should be set up based on karst mountains and valleys in southern of Jinan City. It is suggested that the bare carbonate rock continuous mountain foot line in the direct recharge area should be taken as the south control red line of urban development and included in the overall planning. The urban landscape is mainly displayed in the main axis based on karst mountains and springs, constructing East-West Axis-characteristic Landscape Belt along the Wufeng Mountain-Langmao Mountain-Hero Mountain-Qianfo Mountain-Long cave-Panlong cave-Jinping Mountain line and North-South Axis Landscape Belt along the Baotu Spring- Qianfo Mountain line, Baiquan-Panlong cave line, Baimai spring-Dajian Mountain line. Based on the karst river valleys and the river system, the urban spatial pattern is constructed, forming ecological corridor, restoring infiltration function of river. The form of urban construction should be shaped based on karst landform and the river system. The main form is semi-star like radiation type and the combination of central intensive type and zonal type. Based on the whole protection of karst geomorphology system and the scientific molding of karst landscape, the ecological landscape city with the symbiosis of spring and urban can be built. 相似文献
255.
针对基于出行的时空特征分析在解释老年人不同活动出行行为差异上的不足,根据昆明城市老年人407份有效问卷调查和54份追踪访谈,对基于活动的出行行为特征进行分析。采用结构方程模型分析方法,对出行行为特征参数间的关系进行建模计算,得到了属性、活动因素与出行行为以及出行行为各参数间的关联性。研究结果显示:老年人不同活动的出行特征差异显著,与活动密切相关的出行行为特征参数间有较强的关联性,表现为活动对出行方式和出行强度、出发时刻对出行方式、出行方式对出行强度具有较强的影响。 相似文献
256.
《Chemie der Erde / Geochemistry》2015,75(3):287-300
The chemical and isotopic characteristics (oxygen, hydrogen, and strontium) of spring waters and isotopic compositions of helium (He) and neon (Ne) in gases escaping from spring waters in the Lanping–Simao Basin are studied. A total of twenty-one spring water samples (twelve hot springs, four cold springs, and five saline springs) and eleven gas samples were collected from the study area, including one spring and one gas sample from northern Laos. It is found that saline spring waters in the study area are of chloride type, cold spring waters are of carbonate type or sulfate type, and hot spring waters are of various types. High total dissolved solids levels in saline springs are significantly related to Upper Cretaceous–Paleocene salt-bearing strata. On the basis of hydrochemical geothermometry, the reservoir temperatures (Tr) for hot springs, cold springs, and saline springs are 65.5–144.1, 37.8–64.4, and 65.1–109.0 °C, respectively, and the circulation depths of saline springs are much larger than those of hot and cold springs. The oxygen and hydrogen isotopic compositions of springs in the Lanping–Simao Basin and northern Laos are primarily controlled by meteoric waters with obvious latitude and altitude effects, and are also influenced by δ18O exchange to some extent. Most Sr2+ in spring waters of the study area is derived from varied sources (carbonate, evaporite, and silicate mineral dissolution), and the Sr isotopic compositions are greatly influenced by volcanic rocks. Wide distribution of crust-derived He in the Lanping–Simao Basin and northern Laos reveal that faults in these areas may not descend to the upper mantle. It is concluded that water circulation in the study area may be limited above the upper mantle, while saline springs may originate from the Upper Cretaceous–Paleocene evaporites. Hydrochemical characteristics demonstrate affinities among the Lanping–Simao Basin, northern Laos, and Yanjing, eastern Tibet, while disaffinities are observed between these areas and Tengchong on the basis of the hydrochemical characteristics and noble gas isotopic compositions. 相似文献
257.
地震射线走时的求取方法是叠前时间偏移研究的核心问题之一,也是影响计算时间域角道集角度精确性的关键因素之一.本文基于Kirchhoff叠前时间偏移,应用第一类切比雪夫多项式,对弯曲射线对称走时加以改进,引进非对称项,优化后得到切比雪夫非对称走时方程,与高精度走时进行比较和误差分析,再将该走时求取方法应用于时间域角道集的求取中,得到地下较真实的入射角.通过模型计算和实际地震资料处理证明,此种非对称走时及其角道集的求取方法具有精度高、计算量少的优点. 相似文献
258.
Abstract The instantaneous unit hydrograph (IUH) of a watershed is the result of one instantaneous unit of rainfall excess distributed uniformly over the watershed. Although the geomorphological characteristics of the basin remain relatively constant, the variable characteristics of storms cause variations in the shape of the resulting hydrographs. It is, therefore, inadequate to use one typical IUH to represent the hydrological response generated from any specific storm. In this study, a variable IUH was derived that directly reflects the time-varying rainfall intensity during storms. The rainfall intensity used to generate the variable IUH at time t is the mean rainfall intensity occurring from the time t—T c to t in which T c is the watershed time of concentration. Hydrological records from three watersheds in Taiwan were used to demonstrate the applicability of the proposed model. The results show that better simulations can be obtained by using the proposed model than by using the conventional unit hydrograph method, especially for concentrated rainstorm cases. 相似文献
259.
Abstract The time of concentration is a primary parameter for a variety of modern hydrological models adopted in professional and scientific communities. Nevertheless, a universally accepted working definition of this parameter is currently lacking and several definitions can be found in the technical literature along with related estimation procedures. This study brings to light the inherent variability of these definitions through the empirical analysis of four small basins. These case studies demonstrate that available approaches for the estimation of the time of concentration may yield numerical predictions that differ from each other by up to 500%. Editor D. Koutsoyiannis Citation Grimaldi, S., Petroselli, A., Tauro, F. and Porfiri, M., 2012. Time of concentration: a paradox in modern hydrology. Hydrological Sciences Journal, 57 (2), 217–228. 相似文献
260.