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621.
湿地水环境安全及其评价指标体系研究 总被引:1,自引:0,他引:1
在提出湿地水环境安全内涵的基础上,构建了湿地水环境安全评价指标体系,重点建立了河流型湿地、湖泊型湿地和库塘型湿地水环境安全评价指标体系。 相似文献
622.
杭州西溪湿地首期工程区浮游植物群落结构及与水质关系 总被引:3,自引:1,他引:2
2007年1-12月,调查了西溪湿地(Ⅰ-Ⅳ站)浮游植物的属类组成、密度和生物多样性指数,并将水质理化参数与藻类的群落指标进行相关性分析.4个采样站中共发现8门56个属藻类,其中绿藻门和硅藻门占73.21%.Ⅰ-Ⅳ站藻类年均密度分别为2.88×10~8、0.37×10~8、0.47×10~8和0.71×10~8cells/L,其中绿藻门和隐藻门占总浮游植物密度的93.76%,优势属为小球藻属(Chlorella)、隐藻属(Cryptomonas)和衣藻属(Chamydomonas).Ⅰ-Ⅳ站藻类Margle属多样性指数分别为1.17、1.10、1.08和1.06.根据藻类各项指标值,西溪湿地已遭受污染,水体为富营养型.相关分析结果表明:Ⅰ站和Ⅲ站的浮游植物密度对数与COD_Mn指数呈极显著的正相关关系(P<0.01),Ⅰ-Ⅳ站浮游植物密度对数与水质电导率之间均有显著或极显著的正相关关系. 相似文献
623.
The rivers across Sanjiang Plain are an important path in transferring total dissolved iron (TDFe) into Okhotsk Sea. Distribution of TDFe in main rivers (Amur River, Ussuri River, and Songhua River) and marshy rivers (Yalv River, Bielahong River, and Naoli River) of Sanjiang Plain from 2005 to 2008 was investigated. TDFe concentrations ranged from 0.05 to 6.40 mg L?1 (mean 0.76 mg L?1) and the TDFe species are in the following order: Colloidal iron > ionic iron > complexed iron. Compared with the main rivers, the marshy rivers showed higher TDFe concentration and dissolved organic carbon concentration (DOC), and lower pH value. TDFe concentrations were influenced by several factors, whereas, the concentration of DOC, , and showed remarkable correlation through Spearman correlation coefficient analysis. The rivers mostly showed high TDFe concentration on May and October when the farm activities frequently occur. After 50 years' cultivation of wetlands, the free iron (Fe2+ and Fe3+) showed distinct decrease from 195 to 88.2t in Naoli River. Land use change had decreased TDFe output in rivers of Sanjiang Plain because of the changed concentration and component of DOC, which had higher affinity and selectivity with iron. 相似文献
624.
Impact of water resource exploitation on the hydrology and water storage in Baiyangdian Lake 总被引:4,自引:0,他引:4
Water resources development and exploitation are critical for a viable and sustainable modern human society. Unfortunately, however, there is a considerable water storage depletion and environmental degradation in especially (semi)‐arid river basins due to the forces of population growth, urbanization, industrialization and intensive agricultural irrigation. Addressing water storage depletion is not only a question of research, but is very much a question of developing appropriate countermeasures to preserve valuable/fragile ecological systems. As one such effort, this study analyzes the hydrology and storage in Baiyangdian Lake as affected by water resources development and exploitation in the Baiyangdian Lake Catchment of Northern China. Three models, WetSpass (Water and Energy Transfer between Soil, Plants and the Atmosphere under quasi‐Steady State), WATBUD (Water Budget) and MODFLOW (USGS three‐dimensional finite‐difference groundwater flow model) were used in combination to simulate the hydrogeologic conditions in the lake catchment for 1956–2008. The model‐calibrated values are in good agreement with the measured values, with R2 > 0·8 and RMSE < 10% of measured values. Runoff, the primary source of water for the lake storage, has steadily declined due mainly to multiple dam construction and reservoir impoundments in the headwater valleys and rivers in the catchment. In addition to dwindling runoff, groundwater levels have declined considerably due to over‐abstraction, mainly for agricultural irrigation. Additionally, evaporation or evapotranspiration is increasing in the lake catchment due to rising temperatures. The worsening hydrological conditions, amid the harsh semi‐arid climate, have resulted in considerable depletion of the storage and hydrology of Baiyangdian Lake. Sustainable countermeasures like agricultural water‐saving and infusion of external water (e.g., via by the South–North Water Transfer Project) could be a viable option for preserving not only the hydrology of the lake catchment, but also storage in Baiyangdian Lake. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
625.
626.
鄱阳湖人工控制与湿地生态保护 总被引:2,自引:0,他引:2
从考察鄱阳湖湿地生态特征入手,探讨鄱阳湖控制工程对湖区湿地生态环境的影响,认为只要水位运行调度得当,控湖工程不仅不会破坏湖区湿地生态环境,反而会使湖滩草洲及候鸟越冬环境得到稳定和改善.同时提出了保护鄱阳湖湿地的相关对策. 相似文献
627.
628.
生态补水是维持和改善白洋淀生态环境的重要途径.为研究生态补水对白洋淀水环境的影响,分别在补水前与补水后采集淀水、河水及地下水样品,分析区域地表水和地下水水化学特征.结果表明:(1)白洋淀补水前、后地表水与地下水的水化学组成中Na+为主要阳离子,补水后阴离子以HCO3-为主,淀区南部地表水电导率高;补水后地表水与地下水Ca2+、Mg2+和HCO3-浓度显著增加,水体电导率降低.(2)补水前地下水为Na-HCO3型水,地表水主要为Na-Cl·SO4及Na-Cl·HCO3类型;补水后地表水与浅层地下水向Ca·Mg-HCO3型演化,深层地下水水化学类型基本保持不变.(3)生态补水使白洋淀水位升高,淀区水面积增大,缓解了水资源短缺的问题;同时也使浅层地下水水化学组成发生改变,而深层地下水暂未受到影响.生态补水后,受稀释和混合作用的影响,水体Na+、Cl-和SO42-浓度显著下降,Ca2+、Mg2+及HCO3-浓度增加.在白洋淀生态补水中应"先治污,后补水",以减少补水过程中污染物向淀区的运移,还应注意区域地下水位上升过程中的阳离子交换及水岩相互作用,为合理调配生态补水及改善白洋淀生态环境提供科学依据. 相似文献
629.
630.
淡水湿地水文过程控制着湿地植被景观的形成与演变.基于Landsat TM/ETM+遥感影像数据,利用决策树分类法提取鄱阳湖湿地1992、1999、2006、2012年4期景观信息,通过景观格局指数、转移矩阵和质心迁移法对苔草景观的空间变化及其与水文过程关系进行分析.结果表明:研究期间,鄱阳湖湿地秋、冬季苔草景观分布面积受到水位和退水过程的影响,低水位年的中滩位缓慢退水与低滩位快速出露更有利于苔草景观的扩张;苔草景观的空间格局与水位关系密切,在低水位年份,低位洲滩提前出露,苔草景观分布高程较低,部分低位光滩被苔草所侵占,原苔草分布的部分洲滩转变为芦荻景观,景观的破碎化程度较重,在高水位年份,低位洲滩长期被水体淹没,苔草景观分布高程相对较高,部分芦荻分布区被苔草所侵占,而原苔草景观的部分区域转变为水体和光滩,由于该期间苔草主要集中分布在湖周和入湖河口地带的高位洲滩上,其景观破碎化程度较轻;水位年际间的升降变化会影响苔草景观质心位置,年均水位上升引起景观质心发生向湖岸方向推进,而年均水位下降则会导致苔草景观质心向湖心方向转移. 相似文献