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1.
The Characteristics and Formation of A High-Arctic Proglacial Icing   总被引:1,自引:0,他引:1  
Well‐known from permafrost hydrology, icings (naled or Aufeis) are also frequently encountered at the margins of high‐latitude glaciers. The morphology of a proglacial icing at Scott Turnerbreen in the Norwegian Arctic archipelago of Svalbard is described, and the process of formation is considered in detail. Ground thermal‐regime modelling indicates an equilibrium permafrost depth of at least 200 m in the studied catchment, and it appears unlikely that groundwater contributes to icing formation. Meltwater flow through ice‐marginal drainage channels is accompanied by estimated heat fluxes of up to about 190 W m?2, suggesting that stored meltwater may continue to percolate through thawed sub‐channel sediments when surface runoff is absent during winter. A hydraulic conductivity of 6.9 × 10?3 m s?1 is implied, which is consistent with other studies of glacier drainage systems. The long residence time of winter‐draining meltwater, and solute rejection by refreezing water, account for high observed concentrations of solute in interstitial water in the icing. It has often been asserted that the presence of a proglacial icing indicates that a glacier is polythermal. However, as Scott Turnerbeen is entirely non‐temperate, the presence of an icing cannot always be treated as a reliable guide to the thermal regime of a glacier.  相似文献   

2.
滇池水环境污染的工程治理综述   总被引:9,自引:1,他引:9  
滇池污染治理工作已经进行了20多年,各级政府实施了60个治理项目,投资了几十个亿,但至今滇池水质改观并不明显。这主要是由于近年来滇池流域的社会经济发展迅速,城市及经济规模的急剧扩大,各种污水及固体废弃物的产生量也急剧增加。加上滇池地处盆地最低点,污染物基本上都随水流入滇池。而滇池所处地域地貌条件,决定了其径流面积小,水资源量少,蒸发量大,使滇池富营养化及生态恶化问题日趋严重,使滇池处于严重污染与水资源短缺的双重困难之中。滇池污染治理面临十分严峻的形势,需要在加大污染治理力度的同时,采取更直接有效的措施--通过建设主城区截污工程和外流域引水工程,来改善滇池水环境质量,加快污染治理进程。  相似文献   

3.
阿拉尔垦区土壤盐渍化治理与土地持续利用   总被引:9,自引:0,他引:9  
塔里木河上游的阿拉尔垦区在开垦前主要发育着不同盐渍化程度的土壤。经过30多年的改造,垦区土壤盐渍化治理已取得了一些进展,但也还存在许多问题,解决好这些问题将是今后土壤盐渍化治理与实现土地持续利用的重点。  相似文献   

4.
常用水环境质量评价方法分析与比较   总被引:19,自引:0,他引:19  
为比较水环境质量评价方法的适用性和局限性, 在分析几种常用评价方法的基础上, 利用2008 年长江流域和淮河流域190 个国控断面水质监测数据对单因子评价法、平均污染指数法、内梅罗指数法、灰色关联分析、模糊综合评价、物元可拓评价法、综合水质标识指数法等7 种方法进行实证研究。结果表明:①指标权重的选择对评价结果影响有限, 73.7%的断面评价等级没有因权重发生变化, 但物元可拓法对权重变化较为敏感。②当评价指标污染程度相当时, 平均污染指数法较为适合;当某指标污染程度较为突出时, 内梅罗指数更为恰当。但两者评价结果吻合程度较高, 相关系数达0.94, 且水质越差, 结果越接近。③分级评分法和单因子评价法评价结果差异较大, 仅有10%左右的断面评价等级一致, 且水质越差, 各种方法所得的评价等级差别越大。④各种评价方法具有一定的关联性和互补性, 评价等级相关系数在0.7 左右。综合各种评价方法理论上的优缺点并结合环境管理需求, 单因子评价法和综合水质标识指数法是两种优选方法, 在水环境质量评价中可以组合使用。  相似文献   

5.
Historical and recent changes in the nature of Lake Texcoco, a saline lake in Mexico, are described. These changes are particularly important since they significantly affect water supply, drainage and other urban issues in Mexico City, Mexico's largest city and capital located within the general boundaries of the lake basin and gradually sinking (mean annual sinking rate is 30 cm). After brief reviews of the present status of the lake and background geological, palaeolimnological and climatic features, human activities during historical and recent times are considered. Of particular note have been drainage basin activities, diversion of inflows, pollution and over-exploitation of groundwater and biological resources (especially fish and waterfowl). The major effects of these activities are water shortages, soil erosion, salinization, dust storms, sinking ground, poor water quality and decreased biological resources. Conservation measures are discussed.  相似文献   

6.
查干湖湿地水环境演变特征分析   总被引:1,自引:0,他引:1  
查干湖湿地是吉林西部重要的生态屏障,分析其水环境演变特征,可为保障其水环境安全提供科学依据。利用1982~2011年的水位资料和1985~2011年的水质资料分析其水环境演变特征,采用卡尔森指数法和模糊综合评价法对查干湖湿地进行综合营养状态和水质状况评价。结果显示引松工程通水后湿地水位得以恢复并稳定在129.8~130.3 m;20世纪80年代末湿地水环境大幅改善,水体盐碱化、富营养化、有机污染得以缓解,但2006年以来水质碱化和有机污染加剧,水质由Ⅲ类演变为IV类。现阶段农田退水缓解了主湖区的碱化且暂未加剧其水体富营养化。查干湖水受流域陆源排放、湖泊内源释放及水文情势等多重因素的交互作用,呈以磷素为限制的中营养状态,应控制区域生活污水和畜禽粪便的污染以保护其水环境健康。  相似文献   

7.
Johan Steen     
As a result of recent pedological investigations in the Okstindan Mountains, five major soil groups have been recognized and classified according to drainage characteristics and the degree of mineral horizon visual differentiation in terms of colour. Since Norwegian mountain soils have previously received no detailed classification, it has been attempted to translate the system proposed by the author into those of other northern latitude countries. The problems encountered in translation are discussed, and it is concluded that the Canadian system is perhaps the most suitable for classifying the soils in question, systems of the United States and the Soviet Union being rather less readily applicable.  相似文献   

8.
杨默远  刘昌明  潘兴瑶  梁康 《地理学报》2020,75(9):1831-1844
海绵城市建设的本质是城市水系统的重构,明晰海绵城市系统所涉及的水循环过程是海绵城市研究中最根本、最重要的问题。以海绵城市建设区为研究对象,本文定义了海绵城市系统的内涵,明确海绵城市系统的输入项与输出项,探讨了基于海绵城市系统的城市水循环过程,即海绵城市建设区“大气水—地表水—土壤水—管网水—地下水”转化过程。分别从明确海绵城市建设区的降水与污染物输入、掌握典型海绵设施的径流及污染物转化过程、重视排水管网径流监测与汇流特征参数确定、准确分析海绵城市建设区的径流及污染物外排过程、综合评估海绵城市建设的生态与地下水回补效益共5个方面,系统梳理了海绵城市系统的研究现状及未来的研究要点,以期为海绵城市建设的基础理论研究与工程实践提供启发和帮助,促进中国城镇化转型发展。  相似文献   

9.
Oceanographic data covering the period 1950–1998 are used to determine interannual variations in the convection intensity and water mass structure in the Greenland Sea and adjacent areas. Extremely cold winters throughout 1965–1970 assisted intensification of the water vertical exchange in the Greenland and Norwegian seas. As a result, cold and fresh Greenland Sea Deep Water (GSDW) production was extremely high in the central Greenland Sea while in the southern Norwegian Sea warm and salty water spread downwards. The recent rapid warming in the Greenland Sea Gyre interior from 1980 originates, we argue, from an increase in the Atlantic Water (AW) temperature due to the advection of warm waters into the region with the Return Atlantic Current. The negative water temperature and salinity trends in the upper 300 m layer of the Atlantic Water in the Norwegian Sea prevailed during 1950–1990, whereas during 1980–1990 the water temperature trends are indicative of warming of that layer. Observation series obtained onboard the Ocean Weather Ship Mike confirmed the existence of layers with advectiondriven high oxygen concentrations in intermediate and deep layers. The depth of oxygen maxima and the values of oceanographic parameters at this horizon can be regarded as indicators of the convection intensity in the Arctic domain. A simultaneous rise in NAO index and GSDW temperature points to a link between atmospheric and thermohaline circulation. Weakening in water exchange with the North Atlantic could be the reason for the Polar Water recirculation increase within the Nordic seas.  相似文献   

10.
博斯腾湖的水环境保护与可持续利用对策   总被引:14,自引:1,他引:13  
本文通过实地调查和对1999~2001年的监测资料的分析,从水环境污染物特性、水环境质量变化、排污源分布及排污量计算等方面探讨了博斯腾湖水环境问题及其成因。提出建立博斯腾湖保护区,加大管理检查和执法力度,加强对农田排污水的控制,强化重点排污口和重点城镇生活污水的排污管理,并通过湖滨湿地生态恢复工程、增源节水工程、加速湖水循环工程等措施,保护和改善博斯腾湖水环境  相似文献   

11.
郑连生 《地理研究》1985,4(2):18-25
水利工程设施对防治旱涝及人民生活起了重要作用,但也出现了对环境不良影响的环境水利问题并指出了解决这些问题的措施和意见。  相似文献   

12.
黑河流域水资源动态变化与绿洲发育及发展演变的关系   总被引:4,自引:4,他引:4  
通过探讨流域及绿洲发育及其发展演变的水资源动态变化的特征,阐明它们之间的独特关系,并以此来揭示绿洲系统发育的河流流域地带性问题及特征。研究表明,本区水资源动态变化主要在径流形成、利用和消失三个区域内具有依次性体现的特征。其中占总流域面积10%左右的河川径流形成区,对全流域的水资源动态变化具有先决性作用,并在各个区域水动态变化体现上又受到系统对水的吞吐、留存、蒸散和转化能力大小的影响。因此,河流流域是地域分异现象中通过水流作用所体现出的水平地带性与垂直地带性的一种交汇,同时也是地带性与非地带性系统分异的主要区域。作为河流流域地带发育的绿洲系统,其发展演变规律和特征是相当独特的,如开放性、动态性、脆弱性以及资源有限性等。其中有限的水土资源及其动态变化是制约区域内各层次流域发展及绿洲系统发育的关键,并在不同区段上存在着显著差异性,且彼此间常体现出互为依存、互为消长的依次性制约关系。如水资源量的多寡、质的优劣和时空动态变化及分布、以及人为作用等决定着绿洲类型体现和规模分布、发育层次及阶段或发展演变过程及趋势、和社会经济价值体现等。  相似文献   

13.
This paper compiles new and previously published data on recent calcareous benthic foraminifera (dead and living assemblages) in surface sediment samples from the northern North Sea area, focussing on the dead benthic foraminifera and their relation to the environment. Five dead benthic foraminiferal assemblages have been identified. In Scottish coastal areas Cibicides lobatulus and Rosalina sp. dominate in areas with strong current activity and coarse-grained sediments, whereas C. lobatulus and Trifarina angulosa dominate at similar conditions in the Norwegian coastal areas. Cassidulina laevigata assemblages occur in areas influenced by inflow of Atlantic water into the northern North Sea. In the central part of the Norwegian Channel Uvigerina mediterranea prevails in fine-grained sediments with high organic content and possibly low oxygen content. This species' restricted distribution to the Norwegian Channel could possibly be related to the availability of food. Bulimina marginata and Hyalinea balthica dominate on the Fladen Ground where seasonal stratification is pronounced. This presumably leads to a decrease in the oxygen content in the bottom-waters during part of the year.  相似文献   

14.
Iron mining in the Schefferville, Quebec, area has resulted in the disruption of some small surface drainage systems and the discharge of large amounts of pumped groundwater into them. Major ion concentrations in surface waters is controlled by the occurrence of the Denault (dolomite) formation, and little change is caused by the mining activities. Acidification of some of the waters by acid precipitation is a potential problem, but no health hazards are likely to accrue from the effects of iron mining on the surface water quality.  相似文献   

15.
河湖水系连通特征及其利弊   总被引:9,自引:0,他引:9  
随着水资源以及水环境健康的恶化,河湖水系连通性作为河流健康以及提高水资源利用的一个重要指标在国家"十二五"战略规划中被着重提出。目前,中国对河湖水系连通特征及其对河流健康的影响缺乏足够的认识,本文主要对河湖水系连通的定义、分类、评判指标、影响因素及其对水环境健康的影响进行了一一阐述。分析表明:维持水系连通可以明显地改善...  相似文献   

16.
IntroductionThe karate runoff produchon process is a hydrO-geological process dependent on the shape and bining ofrainfall hydropoh and the spatial vacation Pattern Of landfonns, which is represented by the peak-forestdepression and peak-forest pci ie. It is also affected by tile unique chacterishcs and spatial pattern ofsurface and underground channel netWork exiSted in the karshc catChmellt, where the surface drainagedivide is different from the underground dlainage divide. Along with rese…  相似文献   

17.
本文简要分析了南水北调东线输水工程实施后可能引起黄淮海平原土壤次生盐渍化的原因,并提出了相应的防止措施。  相似文献   

18.
海河流域河流季节化对地下水及生态环境的影响   总被引:7,自引:3,他引:7  
本文在分析海河流域河流季节化趋势的基础上 ,着重探讨河流断流给下游平原地区地下水及生态环境所带来的深刻影响。研究认为 :河流季节化与下游平原地区地下水之间存在着相互影响、互为因果的密切关系 ,河流季节化因地下水超采的日趋严重而愈演愈烈 ;反过来 ,愈演愈烈的河流季节化又极其深刻地影响着地下水的时空分布、补给条件及运动流场等方面 ,同时也给下游平原地区带来一系列的生态环境问题 ,如地下水降落漏斗、地面沉降、海咸水入侵、河流功能衰退、湿地生态退化和水质恶化等。  相似文献   

19.
以SWMM 模型为平台构建已建城市区域排涝模型,以广州市芳村高尔夫地块为研究区域,基于研究区域实测降雨、径流等资料对模型进行参数率定和验证,模拟在不同暴雨重现期下已建城市区域雨水管网的排涝能力。研究结果表明:该区域遭遇2 a 一遇暴雨时,J14、J15 和J31 等3 个排水节点出现积水;当遭遇5 a 一遇时,J15 片区和J31 节点出现较为严重的积水,其中J15 和J31 节点积水量分别达到1 674、546 m³;积水时间分别为0.5、0.4 h。针对研究区域排水管网排涝能力偏低的现状,建议结合LID(Low Impact Development)措施,削减暴雨洪峰流量,提高区域排涝能力。文章构建的已建城市排水管网排涝能力评估方法,可识别区域主要积水黑点及管道满流管段,提供了一种动态、定性和定量评估排水管网能力的方法。  相似文献   

20.
快速城市化进程改变了城市地区原有下垫面,不透水层面积增加,暴雨期间汇流时间缩短,洪峰流量加大,进而导致城市内涝加剧,严重影响城市的防洪安全.本研究以广州市南沙区万顷沙网河区为研究对象,基于水量平衡的调蓄演算方法,对研究区域蓄排设施的规模进行分析;构建MIKE11一维网河模型,对涝区水情进行模拟,校核排涝工程规模,并对工...  相似文献   

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