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1.
对宜昌市沮漳河流域当阳段的水环境进行了调查和评价。通过区域自然环境、社会经济发展、水体功能区、水环境容量等分析以及多个断面数据的监测,表明沮漳河流域当阳段水环境质量不能满足Ⅲ类水体功能区要求,主要超标因子为高锰酸盐指数、NHrN、BOD5、TP、石油类,主要受沿岸工业废水、生活污水及农业面源污染所致。 相似文献
2.
Understanding how hydraulic factors control alluvial river meander migration can help resource managers evaluate the long-term
effects of floodplain management and bank stabilization measures. Using a numerical model based on the mechanics of flow and
sediment transport in curved river channels, we predict 50 years of channel migration and suggest the planning and ecological
implications of that migration for a 6.4-km reach (river miles 218–222) of the Sacramento River near the Woodson Bridge State
Recreation Area, California, USA.
Using four different channel management scenarios, our channel migration simulations suggest that: (1) channel stabilization
alters the future channel planform locally and downstream from the stabilization; (2) rock revetment currently on the bank
upstream from the Woodson Bridge recreation area causes more erosion of the channel bank at the recreation area than if the
revetment were not present; (3) relocating the channel to the west and allowing subsequent unconstrained river migration relieves
the erosion pressure in the Woodson Bridge area; (4) the subsequent migration reworks (erodes along one river bank and replaces
new floodplain along the other) 26.5 ha of land; and (5) the river will rework between 8.5 and 48.5 ha of land in the study
reach (over the course of 50 years), depending on the bank stabilization plan used. The reworking of floodplain lands is an
important riparian ecosystem function that maintains habitat heterogeneity, an essential factor for the long-term survival
of several threatened and endangered animal species in the Sacramento River area. 相似文献
3.
全球海洋塑料污染日益严重,河流是陆地产生的微塑料向海洋传输的重要渠道。珠江微塑料的入海通量排名处于世界前列,其中流经广州市区的虎门入海口的贡献量远高于其他入海口。为探究珠江广州段支流水体微塑料的污染现状并厘清其影响因素,文章对珠江广州段(包括支流和入海口)18个典型采样点位的表层水体微塑料进行了综合分析。结果显示,微塑料的污染丰度为0.123~25.2个/m3。微塑料的主要类型包括聚乙烯、聚丙烯、聚苯乙烯等,其占比远高于其他类型微塑料。珠江广州段接收广州市区及周边城市排放的生活、农业和工业废水,其中纤维主要来自纺织品的洗涤,聚乙烯和聚丙烯均为生活中的常用塑料,聚苯乙烯和聚丙烯多用于生产各类塑料产品(如塑料玩具、泡沫箱等)。在4类监测断面(点)中,入境断面和监控断面的微塑料丰度远高于背景点和入海口。流经人口密集、城市化程度高的区域的支流微塑料丰度远高于其他支流,入海口微塑料丰度最低。可见,人类活动是影响微塑料在不同河段分布的最主要因素。 相似文献
4.
于2020年9月在太滆运河、漕桥河、徐家大塘和竺山湾布设14个监测点位,调查入太湖河道底栖动物群落结构,并采用Goodnight修正指数(GBI)、生物学污染指数(BPI)和多样性指数(H)进行水质生物学评价。结果表明,研究区域共检出底栖动物6纲18种,霍甫水丝蚓(Limnodrilus hoffmeisteri)和中国长足摇蚊(Tanypus chinensis)为优势种,生物多样性由高到低为竺山湾(H=1.20)>徐家大塘(H=1.09)>太滆运河(H=0.67)>漕桥河(H=0.33)。典范对应分析显示,总氮、正磷酸盐等因子与寡毛类生物量呈正相关,叶绿素a、IMn与摇蚊幼虫生物量呈正相关。生物学评价表明,太滆运河处于中重度污染状态,漕桥河、徐家大塘和竺山湾处于中度污染状态。 相似文献
5.
尚勇敏;宓泽锋 《中国人口.资源与环境》2023,33(10):135-145
在碳达峰、碳中和目标下,低碳技术创新合作是优化低碳技术资源配置效率、缩小区域技术差距和实现绿色经济增长的关键途径。作者将联合研发、技术转移两种低碳技术创新合作方式纳入同一模型,分析低碳技术创新合作对绿色经济增长的作用机制;并基于空间计量模型,利用长三角地区2005—2019年低碳技术专利数据及面板数据进行实证检验。研究发现:①长三角低碳技术创新合作网络发育程度总体较低,联合研发网络呈现等级层次性,联合研发主要产生于高能级城市间,而技术转移在跨创新能级城市间相对更多;欠发达城市借助技术转移网络融入联合研发网络,是提升低碳技术创新能力、实现绿色经济增长的有效途径。②长三角低碳技术创新合作促进了绿色经济增长,但其作用效应呈现出复杂性和异质性,低碳技术联合研发更有助于促进知识内化与利用,其绿色经济增长效应高于技术转移。③长三角低碳技术创新合作促进绿色经济增长具有空间溢出效应,本地低碳技术创新合作对周边绿色经济增长具有正向作用,区域一体化是构建低碳技术创新合作网络的有效载体。④长三角低碳技术创新合作促进绿色经济增长具有区域环境依赖性,政府规制、经济水平、人口密度等对其具有显著的积极影响。作者提出以下政策:构建多层次、成体系的长三角低碳技术创新网络体系,积极支持长三角跨区域低碳技术联合研发与转移转化,合理选择低碳技术创新合作模式,积极完善长三角低碳技术创新合作生态系统等。 相似文献
6.
M. Dassenakis F. Botsou V. Paraskevopoulou C. Chikviladge K. Kachiasvili 《Chemistry and Ecology》2006,22(5):379-393
The aim of the present study was to examine the distribution of pollutants in two coastal systems in Georgia: (1) Kubitskali river which flows into the Black sea through the city of Batumi and is polluted mainly from the effluents of an oil refinery; (2) Paliastomi lake, which is a shallow water body at the south-east of the city of Poti. During 2000-2001, two samplings took place in each system, one in the low-flow period and one in the high-flow period. During these samplings, pH, temperature, dissolved oxygen, and salinity were measured in situ, whereas water samples were collected for the analysis of trace metals, nutrients, and organic pollutants with standard methods. The results of the measurements indicate the significant pollution of both systems by ammonia and in the case of Kubitskali River also by oil products. The need for a sustainable management plan of the activities taking place in the river basin is urgent. 相似文献
7.
8.
Joie C. Taylor Nick van de Giesen Tammo S. Steenhuis 《Journal of the American Water Resources Association》2006,42(4):1113-1126
ABSTRACT: Water resource management in West Africa is often a complicated process due to inadequate resources, climatic extremes, and insufficient hydrological information. Insufficient data hinder sustainable watershed management practices, one of the top priorities in the Volta River Basin. This research properly fills in missing data by modeling the hydrological distribution in the Volta River Basin. On average, discharge gages across the basin are missing 20 percent of their monthly data over 20 years. Two methods were used to supplement missing data: a statistically linear model and a conceptual hydrological model. A linear equation, developed from the regression of precipitation and runoff, was used to evaluate the quality of existing data. The hydrological model separates the system into root and groundwater zones. Measured values were used to calibrate the hydrological model and to validate the statistical model. The quality of existing data was analyzed and organized for usability. Accuracy of the hydrological model was also evaluated for its effectiveness using R2 and standard error. It was found that the hydrological model was an improvement from the linear model on a monthly basis; R2 values improved by as much as 0.5 and monthly error decreased. Monthly predictions of the hydrological model were used to fill gaps of measured data sets. 相似文献
9.
David Brandes Gregory J. Cavallo Michael L. Nilson 《Journal of the American Water Resources Association》2005,41(6):1377-1391
Rapid land development is raising concern regarding the ability of urbanizing watersheds to sustain adequate base flow during periods of drought. Long term streamflow records from unregulated watersheds of the lower to middle Delaware River basin are examined to evaluate the impact of urbanization and imperviousness on base flow. Trends in annual base flow volumes, seven‐day low flows, and runoff ratios are determined for six urbanizing watersheds and four reference watersheds across three distinct physiographic regions. Hydrograph separation is used to determine annual base flow and stormflow volumes, and nonparametric trend tests are conducted on the resulting time series. Of the watersheds examined, the expected effects of declining base flow volumes and seven‐day low flows and increasing stormflows are seen in only one watershed that is approximately 20 percent impervious and has been subject to a net water export over the past 15 years. Both interbasin transfers and hydrologic mechanisms are invoked to explain these results. The results show that increases in impervious area may not result in measurable reductions in base flow at the watershed scale. 相似文献
10.
ABSTRACT: Thames Water is one of ten regional Water Authorities established in 1974 to manage all water services in England and Wales. This paper looks back at water reorganization and reviews the achievements and highlights of the last three years. Constitutionally, Water authorities are a combination of a nationalized industry and local authority. This has advantages and disadvantages. Freedom of action, particularly in financial matters, is constrained by Government and official agencies. A severe pollution of the upper Thames and the drought of 1976 tested Thames Water's ability to deal with emergencies. Thames Water does not have an operational monopoly. Private Water Companies supply one third of the water demand and local authorities manage nearly all the sewers. But Thames Water's control over planning and investment ensures that the river basin is managed in a coordinated fashion. Tariff structure changes have led the Authority to bill all its consumers direct. The Thames is a small but intensively used river and vigilance is needed to maintain water quality. Thames Water is proud of the restoration of the tidal Thames from a typical grossly polluted metropolitan estuary to its present excellent condition. The British Government intends to establish a national water industry strategic planning organization but at the same time they affirm that there can be no departure from the principle of integrated river basin management. 相似文献