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951.
本文用可持续发展观对引黄济青工程再评估后认为:水利建设和环境措施同步进行是引黄济青工程取得成功的关键。  相似文献   
952.
渤海环流对近岸海域无机氮分布特征的影响   总被引:2,自引:0,他引:2  
基于2017年渤海近岸海域无机氮监测数据和HYCOM数值模拟结果,分析了渤海环流对无机氮污染分布特征的影响,结果表明渤海无机氮的空间分布特征与其环流结构密切相关:受渤海环流的影响,在春、夏、秋季,无机氮含量高值区呈现不同的强度和范围;在辽东湾,与春季相比,夏季环流结构与春季相反、速度大于春季,盘锦、营口近岸海域夏季无机氮污染范围缩小、含量降低,在锦州近岸海域亦出现高值;在渤海湾、莱州湾,与春季相比,夏季和秋季无机氮含量高值区范围缩小,无机氮含量等值线均随环流向高值中心扩展。  相似文献   
953.
In the years 1987 and 1988 TNO and Akzo Nobel investigated the thermal safety of non-temperature-controlled sea transport of organic peroxides, by modeling and experimenting on several scales. A full-scale test was organised in the summer of 1989, in co-operation with the former Nedlloyd company, in which a sea container with palletised packages, filled with soybean oil as inert liquid and fully equipped with temperature measuring equipment, was transported from Rotterdam, The Netherlands, to Beira, Mozambique, and back. The trip took 2 months.To answer questions stated by the workgroup International Group of Experts on the Explosion Risk of Unstable Substances—subgroup on Energetic and Oxidising Substance (IGUS-EOS) during its meeting in Washington, DC, USA, April 2006, the original data of the sea-container trip were reviewed and applied in a new mathematical model of the sea-container filled with packages, and traveling through tropical sea areas.Analysis of the data from the full-scale test led to defining a worst combination of adverse temperature conditions: constant dead sailing of the wind (wind direction and speed equal to that of the ship), and sunny weather 12 h/day and a mean ambient temperature of 30 °C during 28 days.The effect of sunny weather was put into the model by assigning 24 h averaged excess temperatures to the sun-exposed surfaces. New simulations showed no runaway for the sea container, if filled with an organic peroxide having an self-accelerating decomposition temperature (SADT) of exactly 55 °C.The exaggerated worst case with an improbable mean ambient temperature of 33 °C also does not lead to a runaway.Therefore, the UN criteria for temperature control for organic peroxides are appropriate.  相似文献   
954.
可持续发展下的黄河水资源管理   总被引:1,自引:0,他引:1  
用可持续发展理论为指导。综合运用经济、环境、哲学、生态、水文等多学科知识。全面分析建国后黄河水资源管理中的制度缺陷。进而提出在可持续发展下的黄河水资源管理制度的新思路。文中在分析黄河水权、水价、水权交易的基础上。认为黄河漉域管理应是一个综合性、多中心、全面的管理模式.强调了漉域管理是一种集体行动。其中制度的作用尤为重要。  相似文献   
955.
本文指出,发挥自然地理优势,实现大江大河的网络化,是我国水利建设的总目标,而实现这个目标,科学治理黄河,积极推进水系网络化进程,决策南水北调,成为当务之急。  相似文献   
956.
In order to provide a background picture of the water quality of the Egyptian Red Sea a number of hydrological and chemical parameters have been measured bimonthly in 2000. Few data are available on this area, which is apparently subjected to an increasing human impact due to recreational (swimming and diving), industrial (mainly phosphate shipping and industry) and fishing/harbor activities. The results of the present study indicate that changes in the salinity and pH were not significant with highly oxygenated seawaters. The levels of suspended solids (as total suspended matter, TSM) and chlorophyll-a (Chl-a) were generally low and showed an homogeneous distribution in the study region. The ratio of chlorophyll-a to total suspended matter concentrations increased between November and March and decreased from May to September. Chlorophyll-a was significantly correlated with transparency and total suspended matter concentrations in July, September and November. Nitrogen, phosphorus and reactive silicate concentrations were generally low, and allowed classifying the Egyptian Red Sea coastal water as oligotrophic to mesotrophic. The middle region of the study area, which was located between Safaga and Qusair displayed relatively high phosphate contents when compared with other coastal areas. The high values of N:P ratios indicate that PO 4 -P is the limiting factor for phytoplankton growth in the Red Sea coastal waters, with the possible exception of the middle region. Significant relationships were found between chlorophyll-a concentrations and nutrient levels in different sampling periods. Spatial distribution patterns of the studied variables revealed that productivity of the Red Sea coastal waters is mostly controlled by phosphate concentrations, salinity, temperature and dissolved oxygen.  相似文献   
957.
Recent studies have identified the need to adapt to climate change by allowing landforms and habitats to migrate landward, although implementation of actual adaptation responses is limited. Removing the barriers that shore protection structures create between coastal and upland habitats can reestablish exchanges of sediment and the ecological functions of the natural ecotone. The potential for removing these structures was evaluated in 12 national parks managed by the U.S. National Park Service. Criteria for removal included condition of structures, influence of natural processes, environmental benefits, public safety, and visitor access and use.We found that 145 structures out of a total of 407 could be removed or allowed to deteriorate. We highlight three adaptation projects that are currently being conducted, two of which involve removing structures. Reasons for not taking a more pro-active approach to removing protection structures include (1) conflicting policy directives; (2) presence of key access roads and critical archaeological and historic sites; (3) lack of data; (4) lack of funds and human resources; (5) reluctance to replace known problems with an unknown set of problems; (6) consideration of visitor desires; and (7) reluctance to allow erosion to occur. Demonstration projects are needed to provide information about adaptation strategies that promote enhancement of ecosystem functions. Projects to remove protection structures are likely to be viewed as successful only if results are specified as a positive product, and the distinction between the concept of loss (erosion of existing landforms and habitats) and the concept of gain (evolution of new landforms and habitats) is made clear.  相似文献   
958.
This work focuses on four marine sites of the Mediterranean Sea, north of the Nile Delta, Egypt. Surface-water samples were collected seasonally during 2003. The aim of this study is to assess the levels of some dissolved trace metals (Fe, Mn, Zn, Cu, and Pb) in two environmental conditions. The metal concentrations in the coastal zone were in the following ranges: 11.92-30.45 μg l-1 for Fe, 5.79-17.36 μg l-1 for Mn, 0.87-7.80 μg l-1 for Zn, 0.40-1.87 μg l-1 for Cu, and 1.53-10.31 μg l-1 for Pb. In the sites with continental water input (mixing zone), the metals were scattered in the following ranges: Fe (19.72-60.33 μg l-1), Mn (12.63-35.60 μg l-1), Zn (2.67-22.00), Cu (0.83-8.10 μg l-1), and Pb (1.72-29.7 μg l-1). The results for the metal concentrations showed a remarkable decrease in the levels of the different metals going from the estuaries and outlets into the coastal sea water. Generally, the levels of the metals in the two zones are higher than the background levels of the unpolluted area. A comparison of the trace-metal levels in the coastal zone of the Mediterranean Sea north of Nile Delta with the minimal risk concentration (reported by water-quality criteria, WQC) showed a significantly lower content at the coastal area of the Mediterranean sea of Egypt. The study also indicated that the impact of anthropogenic inputs was limited in the distribution of the metals, except that the Pb content was slightly higher in the area of the mixing zone than that reported for WQC. The relationships between the different trace-metal concentrations and the other parameters (salinity, chlorophyll a and suspended particulate matter) were discussed, and the simple regressions between them were evaluated.  相似文献   
959.
To examine whether U.S. public opinion may become as sharply polarized on adaptation responses as it has been on mitigation policies, we surveyed a sample of urban coastal residents in Maryland (n = 378). We then tested the impact of a community deliberative event (n = 40) with small-group sea level rise discussions as a depolarization strategy. Cultural worldviews which contribute to politically polarized beliefs about climate were predictive of perceptions of sea level rise risk. Living close to flooding hazards also significantly predicted respondents’ perceptions of household or neighborhood risks, but not of risks to the entire county. The event significantly increased topic knowledge among all participants and, among those with a worldview predisposing them to lower risk perceptions, significantly increased problem identification and concern about impacts. These results suggest small-group deliberation focused on local problem-solving may be an effective tool for reducing the polarizing effects of cultural worldviews on decision-making.  相似文献   
960.
黄河小浪底水库水沙调控对DOC输送的影响   总被引:1,自引:1,他引:0  
张永领  王明仕  董玉龙 《环境科学》2015,36(4):1249-1255
于2011年11月至2012年10月在黄河中游的三门峡、小浪底和花园口3个水文站进行每月1次的周期性采样观测以及在调水调沙期间进行连续采样观测,分析了小浪底水库水沙调控对溶解有机碳(DOC)输送的影响.结果表明,在小浪底水库和三门峡水库正常调度期间,三门峡站、小浪底站和花园口站的DOC含量分别为1.97~2.71 mg·L-1、1.87~2.76 mg·L-1和2.07~2.93 mg·L-1,并且均有明显的季节变化;在调水调沙期间,三门峡站、小浪底站和花园口站的DOC含量分别为2.14~3.32 mg·L-1、2.21~2.84 mg·L-1和2.11~2.84 mg·L-1,并且水库排沙阶段的DOC含量明显高于水库泄水阶段的DOC含量.无论是在水库正常调度期间还是在调水调沙期间,DOC含量与TSS含量及流量均没有表现出显著的相关性,而在水库正常调度期间DOC含量与水温呈现显著的正相关关系.11月~次年3月三门峡站和小浪底站的DOC输送量比较接近,4~7月三门峡的DOC输送量明显低于小浪底站,而8~10月三门峡站的DOC输送量又明显高于小浪底站,表明小浪底水库在8~10月大量拦蓄DOC,而在4~7月又将拦蓄下来的DOC排出水库.三门峡站、小浪底站和花园口站DOC年输送量分别为8.6×1010、9.0×1010和9.7×1010g,其中三门峡站9月DOC输送量最多,约占全年DOC输送量的22.0%,小浪底站6月DOC输送量最多,约占全年DOC输送量的17.6%,花园口站7月DOC输送量最多,约占全年DOC输送量的16.7%.在2012年调水调沙期间小浪底站和花园口站的DOC输送量占全年DOC输送量的比例分别为14.7%和13.8%,而三门峡站DOC输送量仅占全年DOC输送量的3.6%.  相似文献   
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